apparatus and process for packaging a product arranged in a support

专利摘要:
APPARATUS AND PROCESS TO PACK A PRODUCT. Process and apparatus for packaging a product disposed on a support. The apparatus comprises a packaging assembly (8) configured to tightly fix one or more sheets of film (18) on one or more supports (4). The packaging assembly includes a lower tool (22) comprising an inner wall (23) that defines a pre-fixed number of seats (23b) for receiving the supports (4), and an upper tool (21) facing the tool bottom (22) and comprising a film retaining plate (36) configured to hold one or more sheets of film, the film retaining plate (36) having a respective active surface (37) configured to receive one or more sheets of film film (18) .. The film retaining plate (36) has a lateral surface that extends substantially perpendicular to a plane defined by the active surface (37), the film retaining plate (36) comprising a plurality of ejectors ( 36c) arranged on the side surface The process includes the step of activating the ejection of a plurality of gas flows around a perimeter of the film holder and on a peripheral portion of the cut film sheets in a direction substantially parallel to a plane defined by the cut and distant film sheet (...).
公开号:BR112016018223B1
申请号:R112016018223-5
申请日:2015-02-10
公开日:2021-02-17
发明作者:Stefano Capitani
申请人:Cryovac, Inc.；
IPC主号:

专利说明:

[0001] [001] The present invention relates to an apparatus and a process for packaging a product. According to certain aspects, the invention relates to an apparatus and a process that improve the configuration and positioning of a film when providing tray cover and wrapping with film. According to other aspects, the invention relates to an apparatus and a process for packaging a product with film. According to other aspects, the invention relates to an apparatus and a process for packaging a product under a controlled atmosphere or under a vacuum. BACKGROUND TECHNIQUE
[0002] [002] Containers are commonly used for packaging food and for a wide variety of other items where a cover is adhered to the container, for example, through the application of heat. Containers and covers can be formed of a number of materials, for example, plastic, metal, or combinations thereof, while the cover is typically supplied in the form of a continuous film and subsequently cut into a suitable shape, either before or after to be adhered to. In some instances, a plastic cover is pre-cut to a suitable shape and subsequently adhered to heat in a plastic tray.
[0003] [003] A method of adhering the cover to the tray involves the use of a laminated plastic cover featuring a layer of metal foil. A power supply provides an electrical current for a nearby induction coil, which induces an electrical current in the metal sheet to develop heat, which melts portions of the cover and the container, and fuses the cover to the edge of the container. For example, EP0469296 describes an induction seal assembly that uses a single coil coil to seal a plastic cover in a plastic container. The assembly includes a nest having a recess for holding a container to be sealed, and a movable sealing head for retaining a cover or sheet membrane and for positioning the cover relative to an opening in the container. Means are provided for securing a portion of the sealing head against a portion of the nest to form a watertight chamber between a lower portion of the sealing head and an upper portion of the nest. The induction seal assembly uses a vacuum source and an inert gas source to discharge air from the container prior to sealing. An induction coil mounted on the sealing head seals the cover on the container by heating some portions of the cover in contact with the container. This solution uses a pre-cut cover, so that it is necessary a means to transport and load the cover to a suitable position for sealing, compromising the efficiency of the packaging process. In addition, document EP0469296 suggests, in general, the use of a roll stock sheet membrane to seal the container while inoperative in relation to the specific way in which the membrane should be cut from the roll in order to form a tray cover with precise fit.
[0004] [004] In order to package products, in particular food products, a vacuum packaging has been developed and refined in the past. Among the known vacuum packaging processes, vacuum film packaging is commonly used to package food products, such as fresh and frozen meat and fish, cheese, processed meat, ready-to-eat meals and the like. Vacuum film packaging is described, for example, in FR 1258357, FR 1286018, AU 3491504, US RE 30009, US 3574642, US 3681092, US 3713849, US 4055672 and US 5346735.
[0005] [005] Vacuum film packaging is basically a thermoforming process. In particular, the product is typically placed on a rigid or semi-rigid support (such as a tray, bowl or bowl). The support with the product placed in it is placed in a vacuum chamber, where a film of thermoplastic material, maintained by a local vacuum in a position above the product placed in the support, is heated to make it more malleable. The space between the support and the film is evacuated. The film is then sealed at the perimeter of the tray to fix its position in relation to the tray and the local vacuum above the film is blocked, releasing the film. When the vacuum inside the chamber is decreased, the vacuum inside the tray will cause the film to be draped downwardly around the product and to be sealed on the surface of the support not covered with the product, thus forming an impermeable film around the product and in the Support.
[0006] [006] US 2007/0022717 describes a machine for packaging a gas-tight object using a film material. The machine features a lower tool to hold two trays and an upper tool featuring cutting devices housed within the upper tool and facing the lower tool. A film is interposed between the upper tool and the lower tool. The upper and lower tools are first closed against each other and then the film is cut to the size of the peripheral edges of the trays by the cutting devices operating inside the upper tool. Sealing tools heat-seal the film cutting regions on the peripheral edge of the tray. A vacuum is located in the region surrounding the tray to cause a deep drawing of the film. In the document, it is also mentioned that the same device can be used to seal trays with films that are not formed by deep drawing to form a film on the product.
[0007] [007] Document 2005/0257501 describes a machine for packaging a product arranged in a tray. The machine features a lower tool for holding the tray and an upper tool with a cutting device. During operation, the film is attached along an edge that surrounds the tray and is deformed by the upper tool in a direction that extends away from the product. The space surrounding the product is then evacuated, the film and the edge of the tray are sealed, and the film is subsequently cut by the cutting device.
[0008] [008] In relation to the machines described in the documents US 2007/0022717 and US 2005/0257501, the film is cut to the size of the tray inside the chamber formed by the upper tool and the lower tool, by means of cutting devices provided in the upper tool. . Firstly, this disadvantageously requires the provision of a somewhat complex and bulky top tool. In addition, this disadvantageously requires the provision of surplus film with respect to the size of the support, the surplus film having to be quoted from the packaging and discarded during the packaging process or at the end of it. Certainly, the film is presented in the form of a continuous sheet wound on a roll (as shown, for example, in Figure 3 of the document US 2005/0257501). Therefore, the excess film material is necessary to allow the film to be pulled from the roll and to be held in place above the sustained product. In addition, in US 2007/0022717 more than one product-loaded support (ie, two) is packaged in each cycle, so that surplus film is also present between adjacent supports.
[0009] [009] WO2011 / 012652 shows an apparatus for packaging a product in a tray. The machine comprises a first film transfer plate configured to hold a film sheet, heat the film sheet, bring the film sheet to a position above a tray with the product disposed in it, and fix the film sheet to the watertightly. A second film transfer plate is also present. With respect to the first film transfer plate, the second film transfer plate is also configured to hold a film sheet, heat the film sheet, bring the film sheet to a position above a tray with the product disposed in the and attach the film sheet to the tray in a watertight manner. During a first stage of operation of the machine, the first film transfer plate retains a first film sheet and heats the first film sheet, while the second film transfer plate releases a second film sheet, thus allowing the second sheet is directed to a first tray, and, during a second operating step of the machine, the second film transfer plate retains a third film sheet and heats the third film sheet, while the first film transfer plate releases the first sheet of film, thus allowing the first sheet of film to be directed to a second tray. The machine additionally comprises a rotating cylinder suitable for rotating about its X axis, the first film transfer plate and the second film transfer plate being connected to the rotating cylinder so that the positions of the first film transfer plate and of the second film transfer plate are changed when the rotating cylinder rotates around its X axis. A vacuum arrangement allows the removal of air from inside the tray below the film sheet (positioned either by the first or the second film plate). transfer) through at least one hole in the tray. The film transfer plates are configured to release the film sheet, thus allowing the film sheet to be directed to the tray while the vacuum arrangement is removing air from inside the tray.
[0010] [0010] As can be seen from the description above, the use of pre-cut film provides an improvement over known methods and apparatus for packaging products, which rely on cutting excess film from the packaged products, after packaging and sealing the products. themselves. If the dimensions of the film - in particular, the width of the film - and those of the trays are carefully adapted to each other, product packaging using the tray cover provision and film packaging can be carried out effectively without excess film material that it has to be cut from the packaged products. This leads to substantial advantages in terms of minimizing material consumption.
[0011] [0011] However, as shown in some examples above, the excess film material can be used in terms of positioning the film so that the requirements regarding the positioning accuracy of the film can be much less stringent. In addition, in terms of handling the film, surplus portions around the packaged product allow for easy manipulation of the film by the fact that the surplus portions are driven by the packaging apparatus. For example, excess portions of the film can be secured in order to pull the film into position. In other examples, the amount of material in the excess portions may provide a stiffness to the excess portions preventing unwanted bending or other deformations and / or movements that could be detrimental to the packaging process and / or that could lead to imperfections in the packaging (for example, compromised seal or uneven appearance).
[0012] [0012] Consequently, minimizing or eliminating the amount of excess material required for the packaging process can lead to one or more of the following harmful effects.
[0013] [0013] In the tray cover provision, a pre-cut cover is positioned on a film holder above a tray to be sealed, so that the pre-cut film extends beyond the film holder. This facilitates the actuation of a sealing tool on the portions of the film that extend beyond the film holder in order to seal the film in the tray. However, portions of the pre-cut film that extend beyond the film holder are prone to deformation due to numerous factors related to the packaging process: the heat emitted from the sealing tool or other components, the turbulence of the gas or air created with the evacuation and / or creation of the inert atmosphere, the mechanical movement of components of the packaging tool, the mechanical resistance and / or stiffness of the material at certain temperatures related to the process, etc. When such deformation occurs, the quality of the seal may be compromised, possibly leading to a seal of mediocre quality or a defective seal.
[0014] [0014] In film packaging, portions of pre-cut film that extend beyond the sealing tool will typically extend from the corners of the tool, in particular, when the pre-cut film has a rectangular outline and pointed corners, while the tray has a curved outline and curved corners. Here, too, the film can be deformed and have an impact on the quality of the seal and packaging.
[0015] [0015] Therefore, an objective of the invention is to design a process and an apparatus that can efficiently and accurately position and configure a film when providing tray cover or wrapping with film. In particular, an objective of the invention is to position and configure peripheral portions of the film.
[0016] [0016] An additional objective of the invention is to provide a packaging process and apparatus that facilitate effective control of the temperature of a film and / or peripheral portions thereof in order to prevent or eliminate unwanted shrinkage of the film material. SUMMARY OF THE INVENTION
[0017] [0017] One or more of the objectives specified above are substantially achieved by a process and an apparatus according to any of the appended claims. Aspects of the invention are described below.
[0018] [0018] According to the invention, in a first aspect, an apparatus is provided for packaging a product arranged in a support, said support having a base wall and a side wall, said apparatus comprising a packaging assembly configured for sealingly fasten one or more sheets of film to said or more supports. The packaging assembly includes a lower tool comprising at least one inner wall that defines a pre-fixed number of seats for receiving said or more supports, and an upper tool facing the lower tool and comprising a film retaining plate configured for retaining one or more sheets of film, the film retaining plate having a respective active surface configured to receive one or more sheets of film, at least the upper and lower tools cooperating to define a packaging chamber. The packaging assembly is configured to operate at least in a first operating condition, where said packaging chamber is opened to receive one or more sheets of film and, in a second operating condition, where said packaging chamber it is optionally hermetically sealed. The apparatus additionally comprises a film supply assembly configured to supply a continuous film, an active film cut assembly on the continuous film and configured to cut film sheets of pre-fixed length from said continuous film, optionally where the assembly of film cut is located outside said packaging chamber, and a control unit connected to the packaging assembly and configured to command the packaging assembly to move from the first to the second operating condition and vice versa, where the retaining plate film has a lateral surface that extends substantially perpendicular to a plane defined by the active surface, the film retaining plate comprising a plurality of ejectors disposed on the lateral surface, each ejector of the plurality of ejectors being configured to eject a gas flow in a direction substantially parallel to said plane and substantially away from a center of the surface active.
[0019] [0019] In a second aspect according to the first aspect, the apparatus additionally comprises at least one transfer device configured to position the cut film sheets within the packaging chamber and above the respective support, the transfer device including a structure support with a flat retaining surface adapted to receive at least one or more sheets of film cut by the cutting assembly, and one selected from the group of an active mechanism in the packaging assembly and configured to move the upper tool between a first position, when the upper tool is positioned in correspondence with the support structure and configured to retrieve one or more sheets of film from the support structure, and at least a second position, where the upper tool is aligned to the lower tool and configured to position at least a sheet of film above said support, and an active mechanism in the structure - support structure and configured for the relative movement of the support structure with respect to the packaging assembly between a first position, where the support structure is positioned in the cutting assembly, and at least a second position, where the support structure is positioned within said packaging chamber and configured to place at least one sheet of film above said support. The control unit is additionally configured to activate the transfer device to position the cut film sheets inside the packaging chamber and above the respective support, and to synchronize the activation of the transfer device with the passage of the packaging assembly from the first to the second operating condition.
[0020] [0020] In a third aspect according to any one of the first and second aspects, the apparatus additionally comprises a transport assembly configured to move one or more supports along a predefined path for the packaging assembly, the transportation assembly including a conveyor configured to move a pre-fixed number of supports per time, where the control unit is configured to control the conveyor to move the pre-fixed number of supports from a region outside the packaging chamber to a region within the packaging chamber where the support or supports of said pre-fixed number are in vertical alignment with the respective sheets of film, and to synchronize the conveyor in such a way that the movement of the pre-fixed support number from the region outside the packaging chamber to the region inside of the packaging chamber is forced to happen when the packaging chamber is open.
[0021] [0021] In a fourth aspect according to any of the previous aspects, the apparatus additionally comprises at least one vacuum arrangement connected to the packaging chamber and configured to remove gas from said packaging chamber, the vacuum arrangement optionally comprising at least one vacuum pump and at least one evacuation tube that connects the inside of said packaging chamber to the vacuum pump, said control unit being additionally configured to control the vacuum arrangement to withdraw gas from said packaging chamber packaging at least when the packaging assembly is in said second operating condition with said packaging chamber tightly closed, and a controlled atmosphere arrangement connected to the packaging chamber and configured to inject a controlled gas flow into said packaging chamber, the optionally controlled atmosphere arrangement comprising at least one injection device and at least and an injection tube that connects the inside of said packaging chamber to the injection device, said control unit being additionally configured to control said controlled atmosphere arrangement to inject said controlled gas flow at least when assembling packaging is in said second operating condition with said hermetically sealed packaging chamber, where the controlled atmosphere arrangement is configured to inject gas into the packaging chamber including an amount of one or more of N2, O2 and CO2 which is different from the amount of these same gases present in the atmosphere at 20 ° C and at sea level (1 atmospheric pressure).
[0022] [0022] In a fifth aspect according to the fourth aspect, the apparatus includes both the vacuum arrangement and the controlled atmosphere arrangement, where the control unit is configured to control said controlled atmosphere arrangement to start the injection of said controlled gas flow, either after a pre-set delay of activating said vacuum arrangement, or after a pre-set vacuum level has been reached within said packaging chamber, optionally where said control unit is configured to control said controlled atmosphere arrangement to initiate the injection of said controlled gas flow, while said withdrawal of gas from the packaging chamber tip is still in progress. The pump is preferably a type compatible with the type or composition of gas that is used (for example, suitable for a gas mixture having a high oxygen content and, therefore, which is highly flammable).
[0023] [0023] In a sixth aspect according to any of the fourth and fifth aspects, the control unit is configured to operate the vacuum arrangement to remove gas from said packaging chamber and create a pressure vacuum level in the packaging chamber between 10 and 30 kPa (100 and 300 mbar), optionally between 15 and 25 kPa (150 and 250 mbar).
[0024] [0024] In a seventh aspect according to any of the previous aspects, the packaging assembly additionally comprises a main actuator active in at least one tool, said upper tool or said lower tool, the main actuator being controlled by the control unit control. The control unit is configured to act on the main actuator and cause the relative movement of the upper and lower tools, along a main direction, between said first operating condition, where the upper tool is spaced from the lower tool and said packaging chamber is opened to receive one or more of said sheets of film, and said second operating condition, where a closing surface of the upper tool seals against a closing surface of the lower tool to tightly close said chamber packaging with respect to an atmosphere outside the device.
[0025] [0025] In an eighth aspect according to any of the foregoing aspects, the film retaining plate comprises a means for retaining one or more sheets of film in correspondence with said active surface, said means for retaining comprising a or more in the group of a vacuum source controlled by the control unit, the control unit being configured to activate the vacuum source and cause the film retaining plate to receive and retain one or more sheets of film in correspondence with the active surface, mechanical supports associated with the active surface, adhesive portions associated with the active surface, heatable portions associated with the retaining plate and controlled by the control unit to cause heating of the active surface and, therefore, of the film sheet in order to increase the adhesiveness of the film sheet to the active surface, electrical systems associated with the retaining plate and controlled by the control unit to load the active surface with a predetermined polarity.
[0026] [0026] In a ninth aspect according to the eighth aspect, the apparatus additionally comprises a heating structure peripherally associated with the film retaining plate and having a respective heating surface that extends radially outside with respect to the active surface of the retaining plate, where at least when the packaging assembly is in said second operating condition, the heating surface of the heating structure will face an end surface of said inner wall that delimits a respective seat of said seats in the tool bottom, the heating structure and the film retaining plate being relatively mobile with each other along said main direction (A5) in such a way that the heating surface of the heating structure can be selectively positioned in a position where it does not enter in contact with the film sheet and in a position where it comes in contact with the film sheet lm positioned above a support located in one of said seats, and the control unit is configured to control the heating of the heating structure in such a way that the heating surface is brought at least to a first temperature.
[0027] [0027] In a tenth aspect according to any of the previous aspects, the apparatus additionally comprises a heating medium integrated in the film retaining plate and controlled by the control unit, the control unit being configured to control the heating medium such that the active surface of the film retaining plate is brought at least to a second temperature comprised between 150 ° C and 260 ° C, optionally between 180-240 ° C, more optionally between 200-220 ° C. The aforementioned temperatures are at least suitable for materials, such as PET. If PE is used, the temperature range is preferably between 130 ° C and 160 ° C.
[0028] [0028] In an eleventh aspect according to the ninth and eleventh aspects, the control unit is configured to independently control the heating medium and the heating structure and to independently adjust the first and second temperatures.
[0029] [0029] In a twelfth aspect according to any aspect from the ninth to the eleventh, the heating structure comprises one of the following: a metallic body that incorporates at least one resistive and / or inductive element connected to a power supply and the control unit that is configured to control the energy supply to supply current to the resistive or inductive element in such a way as to maintain the temperature of the heating surface within a pre-fixed range around said first temperature; a metallic wire directly conducted through the heating surface of the heating structure, the metallic wire being connected to a power supply and the control unit that is configured to control the power supply to supply current to the metallic wire during discrete time intervals followed by time intervals where no current supply to the metal wire occurs, in particular, where the control unit is configured to control the power supply to supply current to the metal wire, when the film sheet seal on the holder happens ; and a printed circuit formed on said heating surface of the heating structure, the printed circuit being connected to a power supply and to the control unit which is configured to control the power supply to supply current to the printed circuit during time intervals discrete followed by time intervals where no current supply to the printed circuit takes place exclusively, in particular, where the control unit is configured to control the power supply to supply current to the printed circuit, when the sealing of the film sheet takes place on the stand.
[0030] [0030] In a thirteenth aspect according to any aspect of the new to the twelfth, the film retaining plate is rigidly coupled to the upper tool and mounted on it in such a way that the film retaining plate is not relatively mobile with respect to the upper tool at least along said main direction (A5), the active surface is flush with the lower surface of the lower tool, and said active surface of the retaining plate is sufficiently dimensioned to overlap, optionally overlapping completely , to an end surface of said inner wall which delimits a respective seat from said seats in the lower tool.
[0031] [0031] In a fourteenth aspect according to any of the previous aspects, the film retaining plate has a substantially rectangular shape comprising four corners, and where the plurality of ejectors comprises at least one ejector disposed in each of the four corners of the retaining plate. The corners preferably have a rounded shape.
[0032] [0032] In a fifteenth aspect according to one of the previous aspects, the plurality of ejectors is arranged around a perimeter of the film retaining plate defined by the lateral surface, optionally where the plurality of ejectors is spaced in a substantially position equidistant from each other.
[0033] [0033] In a sixteenth aspect according to any of the previous aspects, the plurality of ejectors is in fluid communication with a common pipe configured to supply the gas flow to each ejector of the plurality of ejectors.
[0034] [0034] In a seventeenth aspect according to any of the previous aspects, the plurality of ejectors is angularly arranged with respect to the center of the active surface at substantially the same angular distance with respect to each other.
[0035] [0035] In an eighteenth aspect according to one of the previous aspects, the apparatus additionally comprises a film positioning arrangement connected to the plurality of ejectors and configured to supply the gas flow to the plurality of ejectors, optionally the positioning arrangement of film comprising at least one supply device and at least one supply tube that connects the supply device with the plurality of ejectors.
[0036] [0036] In a nineteenth aspect according to the eighteenth aspect, the control unit is additionally configured to control said film positioning arrangement to supply said gas flow comprising one or more of the following steps: start the supply gas flow, increase the supply of the gas flow, decrease the supply of the gas flow, and interrupt the supply of the gas flow.
[0037] [0037] In a twentieth aspect according to the eighteenth or nineteenth aspect, and according to the fourth or fifth aspect, the gas flow has the same composition as the controlled gas flow injected by the controlled atmosphere arrangement , optionally where the film positioning arrangement comprises a supply switch configured to controllably select a first gas supply source and a second gas supply source from the gas stream, the first gas supply source being configured to supply gas featuring the same composition as the controlled gas flow injected by the controlled atmosphere arrangement, the second source of gas supply being configured to supply air.
[0038] [0038] In a twenty-first aspect according to the eighteenth or nineteenth aspect, the gas flow comprises air.
[0039] [0039] In a twenty-second aspect according to any of the aspects from eighteenth to twenty-first, and according to the fifth aspect, the control unit is configured to perform the steps of controlling said film positioning arrangement for start supplying the gas flow to the ejectors, control said vacuum arrangement to withdraw gas from said packaging chamber, control said controlled atmosphere arrangement to initiate injection of the controlled gas flow, control said disposal arrangement controlled atmosphere to interrupt the injection of the controlled gas flow, and to control said film positioning arrangement to retain the supply of the gas flow to the ejectors.
[0040] [0040] In a twenty-third aspect according to the twenty-second and twenty-third aspects, the step of controlling said vacuum arrangement to remove gas from said packaging chamber additionally comprises controlling the film positioning arrangement to decrease or interrupt supplying gas flow to the ejectors during withdrawal of gas from the packaging chamber, optionally further comprising controlling the film positioning arrangement to restart or increase the supply of gas flow to the ejectors while withdrawing gas from the chamber packaging is still ongoing.
[0041] [0041] In a twenty-fourth aspect according to the twenty-second or twenty-third aspect, and according to the twenty-fourth aspect, the step of controlling the controlled atmosphere disposition to initiate the injection of the controlled gas flow additionally comprises the control of the film positioning arrangement to start supplying a gas to the ejectors having the same composition as the controlled gas flow.
[0042] [0042] In a twenty-fifth aspect according to any of the previous aspects, the packaging assembly additionally comprises at least one side wall movably associated with a tool, the upper tool or the lower tool, where the side wall has a front surface configured to rest against a support surface of the other tool, said top tool or said bottom tool, the side wall is mounted on the packaging assembly in such a way that when the packaging assembly moves from said first operating condition to in said second operating condition, the side wall will correspondingly move from a first position, where the front surface of the side wall is spaced from said support surface so that the packaging chamber is left open to receive one or more of said sheets film, to a second position, where the front surface of the side wall seals tightly there is said support surface in such a way that said packaging chamber is hermetically closed with respect to an atmosphere outside the apparatus.
[0043] [0043] In a twenty-sixth aspect according to the twenty-fifth aspect, and according to the seventh aspect, the control unit is configured, after the packaging assembly has reached the second operating condition, to act on the actuator main and cause a relative additional movement of the upper and lower tools, along the main direction (A5), in such a way that the film sheet held in position by the retaining plate is pressed against the edge of the support and where the relative additional movement it causes a retraction of the side wall against the reaction of a contrast element, which optionally comprises one or more elastic elements.
[0044] [0044] In a twenty-seventh aspect according to one of the previous aspects, the lower tool is provided with multiple seats, each one to host a corresponding support and where the upper tool is provided with a corresponding plurality of retaining plates, each one to retain a respective sheet of film.
[0045] [0045] In a twenty-eighth aspect according to twenty-seventh aspect, the apparatus additionally comprises a plurality of distinct support structures, each comprising a flat retaining surface adapted to receive a respective film sheet from said film sheets, each the supporting structures being movable between at least the cutting assembly, to collect the respective film sheet, and the inside of the chamber, to position the cut film sheet in correspondence with the respective upper tool retaining plate, and a transfer actuator that is active on the support surfaces to allow the movement of the support structures and, therefore, the cut film sheets of the cutting assembly into the packaging chamber, the transfer actuator being controlled by the control unit such a way as to increase a mutual spacing between the support structures before, when or subsequent to the movement of the support structures of the cutting assembly into the packaging chamber.
[0046] [0046] In a twenty-ninth aspect according to any of the previous aspects, the packaging assembly comprises, for each of said seats, numerous impeller elements adapted to move from a release position, where the active portions of the impeller elements are spaced from the active surface of the retaining plate, to a latching position, where active portions of the pusher elements press the edge portions of the cut film sheet against said active surface of the retention plate, where said pusher elements include a selected of the group of tongue-shaped stops pivotally mounted on the upper tool and active in correspondence with the corners of said seats, tongue-shaped stops mounted on the lower tool, configured to be vertically moved, and active in correspondence with the corners of said seats , oscillating bars pivotally mounted on the top tool and active in correspondence with the lateral edges of said seats, and oscillating bars mounted on the lower tool, configured to be vertically moved, and active in correspondence with the lateral edges of said seats. Optionally, at least one pusher actuator is active on said pusher elements under the control of said control unit which is configured to activate said pusher actuator and move the pusher elements from said release position to said engagement position and vice versa .
[0047] [0047] In a thirtieth aspect according to any of the preceding aspects, the apparatus additionally comprises a frame that conducts the transport assembly, the packaging assembly, the film supply assembly, which comprises a sustained roll of film by a roll holder driven by said frame, and the film cutting assembly, which comprises at least one blade driven by said frame and active in a position located between said packaging assembly and said film supply assembly. The control unit is configured to execute the following cycle: command the transport assembly to move said support to said packaging chamber; command the film cut assembly to cut at least one sheet of film; controlling the transfer device to position the cut film sheet inside the packaging chamber and above the respective support; commanding the upper tool to retain the cut sheet of film above, and at a distance from said support; commanding the packaging assembly to move from the first to the second operating condition (optionally commanding the vacuum arrangement to remove air from said hermetically sealed packaging chamber and / or commanding the controlled atmosphere arrangement to inject a gas or mixture gases in the packaging chamber); and commanding the packaging assembly to tightly fix the film sheet on said support.
[0048] [0048] According to the invention, in a thirty-first aspect, there is provided a process for packaging a product disposed in a support, said support having a base wall and a side wall, said process optionally using an apparatus according to any of the preceding embodiments, the process comprising the steps of unwinding a film from the roll, transversely cutting the unwound portion of film and preparing a cut film sheet, moving the cut film sheet into a packaging chamber of a packaging assembly and in the vicinity of a film holder disposed within the packaging chamber, the film holder having an active surface, activate the ejection of a plurality of gas streams around a perimeter of the film holder, the plurality of streams of gas being ejected over a peripheral portion (18b, 18c) of the cut film sheet in a direction substantially parallel to a plane defined by the film sheet c upright and away from a center of the cut film sheet, in order to position the peripheral portion (18b, 18c) substantially within the plane of the cut film sheet, move a support for the packaging chamber and below the film support, substantially in superposition with the cut film sheet, optionally the cut film sheets being kept at a sufficient distance to allow gas to circulate within the support, move the support to a position substantially in contact with the cut film sheet, disable the ejection the plurality of gas flows, and heat seal the film sheet on the support.
[0049] [0049] Optionally, the process comprises the steps of tightly closing the packaging chamber with the cut film sheet held above the holder after moving the holder in the packaging chamber and below the film holder, and opening the packaging chamber hermetically closed, and to move the support with the sealingly cut film sheet attached to it outside the packaging chamber after the heat sealing of the film sheet to the support.
[0050] [0050] In a thirty-second aspect according to the thirty-first aspect, the cutting of the film into sheets of film takes place outside the packaging chamber at a station removed from the location where the sheets of film are attached to the supports, and where the support comprises a horizontal edge that radially emerges from said side wall, optionally where the sheet of film is cut to a size identical to that of the outer edge of the edge or to a size radially smaller than the outer edge of the edge, but sufficient to seal tightly the mouth of the tray and sealingly engage the upper surface of the rim.
[0051] [0051] In a thirty-third aspect according to the thirty-first or the thirty-second aspects, the process additionally comprises the evacuation of the hermetically sealed packaging chamber, and / or the injection of a controlled gas flow, the controlled gas flow being configured to create a modified atmosphere within the chamber.
[0052] [0052] In a thirty-fourth aspect according to the thirty-first or the thirty-second aspects, the process additionally comprises the steps of evacuating the hermetically closed packaging chamber until a pressure comprised between 100 and 300 mbar, optionally between 150 and 250 mbar, is reached inside said packaging chamber and then - while the film sheet is kept at a distance from the mouth of a support - inject a controlled gas flow into the packaging chamber, the controlled gas flow being configured to creating a modified atmosphere, optionally where the injection of said controlled gas flow to create a modified atmosphere is performed while the evacuation step is still in progress; and uniformly heating the film sheet if the film sheet is not heat shrinkable or heating a peripheral portion of the film sheet if the film is heat shrinking; and approaching the film sheet to the support and sealingly attaching it to the support rim, preferably the step of heating the film sheet or the step of heating the peripheral portion of the film sheet being performed substantially at the same time as the step of bring the film sheet close to the support.
[0053] [0053] In a thirty-fifth aspect according to aspects of the thirty-first to the thirty-third, the process additionally comprises the steps of heating a peripheral portion of the film sheet at a first temperature suitable for heat sealing, and heating a central portion at a second temperature suitable to make the film sheet deformable, optionally the second temperature being equal to or greater than the first temperature. BRIEF DESCRIPTION OF THE DRAWINGS
[0054] [0054] The present invention will be clearer by reading the following detailed description, provided by way of example and not by way of limitation, to be read with reference to the attached drawings, in which:
[0055] [0055] Figure 1 is a layout of a schematic side view of an apparatus according to the aspects of the invention, the layout of the apparatus of Figure 1 being able to be present in all embodiments described here;
[0056] [0056] Figures 2-11 are schematic side views referring to a first embodiment of a packaging apparatus according to the aspects of the invention, in which views are shown consecutive phases of a packaging process operated by the apparatus of the first embodiment, the apparatus and the process according to these figures being destined for the tray cover;
[0057] [0057] Figures 12-16 are schematic side views referring to a second embodiment of a packaging apparatus according to the aspects of the invention, in which figures, consecutive stages of a packaging process operated by the apparatus of the second embodiment are shown, the apparatus and the method according to these figures being intended to form a film package;
[0058] [0058] Figure 17 is a schematic plan view showing a support and a sheet of film in relation to the overlap in correspondence with the packaging apparatus; and
[0059] [0059] Figure 18 is a view taken according to the XVIII plane of Figure 17 and shows a cross section of the packaging apparatus referring to the effectors, according to certain aspects of the invention. DEFINITIONS AND CONVENTIONS
[0060] [0060] It should be noted that, in the present detailed description, corresponding parts shown in the various figures are indicated with the same reference numerals through the figures. In addition, it is further noted that the figures are not shown to scale and the parts and components shown therein are schematic representations.
[0061] [0061] In the following description and in the claims, the apparatus and the process refer to the packaging of a product inside a support or tray. The product can be a food product or another product.
[0062] [0062] As used here, support 4 indicates a container of the type having a base wall 4a, a side wall 4b and optionally an upper rim 4c which emerges radially from the side wall 4b. It will also be noted that, for the purposes of the present description, the terms "tray" and "support" have the same meaning and can be used interchangeably. The tray or support 4 can have a rectangular shape or any other suitable shape, such as round, square, elliptical, etc. Trays can be manufactured by thermoforming or injection molding. TRAYS OR SUPPORTS
[0063] [0063] The trays or supports 4 described and claimed herein can be formed from a single-layer or, preferably, multiple-layer polymeric material. In some examples, the supports are substantially flat and / or formed of foam material.
[0064] [0064] In the case of a single layer material, suitable polymers include, for example, polystyrene, polypropylene, polyesters, high density polyethylene, poly (lactic acid), PVC, and the like, whether foam or solids.
[0065] [0065] Preferably, tray 4 is provided with gas barrier properties. As used here, this term refers to a film or sheet of material that has an oxygen transmission rate of less than 200 cm3 / m2diaatm, less than 150 cm3 / m2diaatm, less than 100 cm3 / m2diaatm, as measured according to the ASTM D-3985 standard at 23 ° C and 0% relative humidity. Suitable materials for gas barrier monolayer 4 thermoplastic trays are, for example, polyesters, polyamides and the like.
[0066] [0066] If tray 4 is formed of a multi-layer material, suitable polymers are, for example, ethylene homo- and copolymers, propylene homo- and copolymers, polyamides, polystyrene, polyesters, (poly) lactic acid , PVC and the like. Part of the multilayer material can be solid and part can be foam.
[0067] [0067] For example, tray 4 may comprise at least one layer of a polymeric foam material chosen from the group consisting of polystyrene, polypropylene, polyesters and the like.
[0068] [0068] Multilayer material can be produced either by coextrusion of all layers using coextrusion techniques or by glue or heat lamination, for example, from a rigid foam or solid substrate with a thin film, usually called " coating".
[0069] [0069] The thin film can be laminated on the side of tray 4 in contact with product P or on the far side of product P, or on both sides. In the latter case, the laminated films on both sides of tray 4 can be the same or different. A layer of an oxygen barrier material, for example, copolymer (ethylene-co-vinyl alcohol) is optionally present to increase the shelf life of the P packaging process.
[0070] [0070] Gas barrier polymers that can be used for the gas barrier layer are PVDC, EVOH, polyamides, polyesters and mixtures thereof. The thickness of the gas barrier layer will be adjusted in order to provide the tray with an adequate oxygen transmission rate for the specific packaged product.
[0071] [0071] The tray may also comprise a heat sealable layer. In general, the heat sealable layer will be selected from polyolefins, such as ethylene homo- or copolymers, propylene homo- or copolymers, ethylene / vinyl acetate copolymers, ionomers, and homo- or copolyesters, for example, PETG, a glycol modified polyethylene terephthalate. Additional layers, such as adhesive layers, to better adhere the gas barrier layer to the adjacent layers, may be present in the gas barrier material for the tray and are preferably present depending, in particular, on the specific resins used for the coating layer. gas barrier.
[0072] [0072] In the case of a multilayer material used to form tray 4, part of this structure may be foam and part may not be. For example, tray 4 may comprise (from the outermost layer to the innermost food contact layer) one or more structural layers, typically of a material, such as foam polystyrene, foam polyester or foam polypropylene, or a molten sheet of, for example, polypropylene, polystyrene, poly (vinyl chloride), polyester or cardboard; a gas barrier layer and a heat sealable layer.
[0073] [0073] Tray 4 can be obtained from a sheet of polymeric foam material with a film comprising at least one oxygen barrier layer and at least one laminated surface layer on the side facing the packaged product. so that the surface sealing layer of the film is the food contact layer of the tray. A second film, whether barrier or not, can be laminated to the outer surface of the tray.
[0074] [0074] Four specific tray formulations are used for food products that require heating in a conventional oven or microwave oven before consumption. The surface of the container in contact with the product, that is, the surface involved in forming the seal with the covering film, comprises a polyester resin. For example, the container can be formed of cardboard coated with a polyester resin or it can be integrally formed of a polyester resin. Examples of suitable containers for the packaging of the invention are CPET, APET or APET / CPET containers. Such containers may or may not be foam.
[0075] [0075] Trays 4 used in tray cover or film wrapping applications containing foam parts have a total thickness of less than 8 mm, and can, for example, be between 0.5 mm and 7.0 mm. most often between 1.0 mm and 6.0 mm.
[0076] [0076] In the case of a rigid tray containing no foam parts, the total thickness of the single-layer or multi-layer thermoplastic material is preferably less than 2 mm, which can, for example, be between 0.1 mm and 1 , 2 mm, most often between 0.2 mm and 1.0 mm. THE FILM OR FILM MATERIAL
[0077] [0077] The film or film material 10a described herein can be applied to the tray or support 4 to form a cover on the tray (for example, for modified atmosphere packaging (MAP)) or a cover similar to a film in contact with the tray and the product, and corresponding to the outline of the product.
[0078] [0078] The film for film packaging applications can be formed of a flexible multilayer material comprising at least a first heat sealable outer layer, an optional gas barrier layer and a second heat resistant outer layer. The heat-sealable outer layer may comprise a polymer capable of being welded to the inner surface of the supports that carry the products to be packaged, for example, ethylene homo- or copolymers, such as LDPE, ethylene / alpha-olefin copolymers, ethylene copolymers / acrylic acid, ethylene / methacrylic acid copolymers, and ethylene / vinyl acetate copolymers, ionomers, copolyesters (for example, PETG).
[0079] [0079] The optional gas barrier layer preferably comprises oxygen impermeable resins such as PVDC, EVOH, polyamides and mixtures of EVOH and polyamides. The heat-resistant outer layer may be formed of ethylene homo- or copolymers, ethylene / cyclic olefin copolymers, such as ethylene or norbornene copolymers, propylene homo- or copolymers, ionomers, (co) polyesters, (co) polyamides .
[0080] [0080] The film can also comprise other layers, such as adhesive layers or bulky layers to increase the thickness of the film and improve its properties regarding strength and deep drawing. In particular, ionomers, ethylene / vinyl acetate copolymers, polyamides and polyesters are used in bulky layers. In all layers of the film, the polymer components can contain appropriate amounts of additives normally included in such compositions. Some of these additives are preferably included in the outer layers or in one of the outer layers, while some others are preferably added to the inner layers. These additives include slip and anti-blocking agents, such as talc, waxes, silica and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, cross-linked inhibitors, cross-linked stimulators, UV absorbers, odor absorbers, eliminators of oxygen, bactericides, antistatic agents and similar additives known to those skilled in the art of packaging films.
[0081] [0081] One or more layers of the film can be cross-linked to improve the film's resistance and / or its heat resistance. Cross-linking can be achieved with the use of chemical additives or by subjecting the film layers to an energetic radiation treatment. Films for wrapping with film are typically manufactured in order to show low shrinkage when heated during the packaging cycle. These films generally shrink less than 15% at 160 ° C, more often less than 10%, even more often less than 8%, both in the longitudinal and in the transverse direction (ASTM D2732). The films generally have a thickness between 20 microns and 200 microns, more often between 40 and 180 microns, and even more frequently between 50 microns and 150 microns.
[0082] [0082] Film packs are generally "easy to open", that is, they are easily opened with manual separation of the two membranes, usually starting from a point like a corner of the package where the top membrane was not purposely sealed in the support. In order to achieve this characteristic, the film or the tray can be provided with a suitable composition, allowing an easy opening of the package, as is known in the art. Typically, the sealing composition and / or the composition of the adjacent layer of the tray and / or the film are adjusted in order to achieve the easy opening characteristic.
[0083] [0083] Several mechanisms can occur while opening an easy-to-open package.
[0084] [0084] In the first one ("easy detachable opening"), the packaging is opened with the separation of the film and the tray at the sealing interface.
[0085] [0085] In the second mechanism ("adhesive failure"), the opening of the packaging is achieved through an initial rupture through the thickness of one of the sealing layers followed by the delamination of this layer from the underlying support or film.
[0086] [0086] The third system is based on the "cohesive failure" mechanism. The easy opening characteristic is achieved by the internal rupture of a sealing layer that, during the opening of the package, breaks along a plane parallel to the layer itself.
[0087] [0087] Specific mixtures are known in the art to obtain such opening mechanisms, to ensure the release of the film from the surface of the tray, such as those described in EP1084186.
[0088] [0088] On the other hand, in case the film 10a is used to create a cover on the tray or support 4, the film material can be obtained by coextrusion or lamination processes. The cover films can have a symmetrical or asymmetric structure and can be of the single layer or multiple layers type.
[0089] [0089] Multilayer films have at least 2, more often at least 5, and even more often at least 7 layers.
[0090] [0090] The total thickness of the film can vary from 3 to 100 microns, more often from 5 to 50 microns, even more often from 10 to 30 microns.
[0091] [0091] The films can be optionally cross-linked. Cross-linking can be performed by irradiation with high-energy electrons at an appropriate dosage level, as known in the art. The cover films described above can be heat-shrinkable or heat-cured. Heat shrink films typically show a free shrinkage value measured at 120 ° C according to ASTM D2732 in the range of 2 to 80%, more often from 5 to 60%, even more often from 10 to 40%, both in the longitudinal and in the longitudinal direction. in the transverse direction. Heat-cured films have free shrinkage values less than 10% at 120 ° C, preferably less than 5%, both in the longitudinal and in the transverse direction (ASTM D2732).
[0092] [0092] The cover films comprise at least one heat sealable layer and an outer film layer, which is generally formed of polyolefin or heat resistant polymers. The sealing layer typically comprises a heat sealable polyolefin which, in turn, comprises a single polyolefin or a mixture of two or more polyolefins, such as polyethylene or polypropylene or a mixture thereof. The sealing layer can be additionally provided with anti-fog properties by incorporating one or more anti-fog additives in its composition or by coating or spraying one or more anti-fog additives on the surface of the sealing layer by a technician known in the art. technical.
[0093] [0093] The sealing layer may additionally comprise one or more plasticizers. The film layer may comprise polyesters, polyamides or polyolefin. In some structures, a mixture of polyamide and polyester can be advantageously used for the film layer. In some cases, the cover films comprise a barrier layer. Barrier films typically have an OTR (rated at 23 ° C and 0% R.H. according to the ASTM D-3985 standard) below 100 cm3 / (m2diaatm) and more often below 80 cm3 / (m2diaatm). The barrier layer is generally formed from a thermoplastic resin selected from a saponified or hydrolyzate product of ethylene-vinyl acetate copolymer (EVOH), an amorphous polyamide and a vinyl-vinylidene chloride and mixtures thereof. Some materials comprise an EVOH barrier layer sandwiched between two polyamide layers. The film layer typically comprises polyesters, polyamides or polyolefin.
[0094] [0094] In some packaging applications, the covering films do not comprise any barrier layer. Such films generally comprise one or more polyolefins defined herein. Non-barrier films typically have an OTR (rated at 23 ° C and 0% RH according to ASTM D-3985) from 100 cm3 / (m2diaatm) to 10000 cm3 / (m2diaatm), more typically up to 6000 cm3 / (m2diaatm ).
[0095] [0095] Compositions peculiar to the polyester base are those used for the provision of cover for ready-to-eat meal packaging. These films are typically used in combination with polyester-based substrates.
[0096] [0096] For example, the container can be formed of cardboard coated with a polyester resin or it can be integrally formed of a polyester resin. Examples of suitable containers for packaging are CPET, APET or APET / CPET containers, whether foamed or not.
[0097] [0097] Generally, biaxially oriented PET is used as the coating film due to its high thermal stability at heating / cooking temperatures of standard foods. Often, biaxially oriented polyester films are heat-cured, that is, non-heat-shrinkable. To improve the heat sealability of the PET cover film in the container, a heat sealable layer of a material with a lower melting point is generally provided in the film. The heat sealable layer can be coextruded with the PET base layer (as described in EP-A-1529797 and WO2007 / 093495) or can be coated by solvent or extrusion onto the base film (as described in US 2,762. 720 and EP-A-1252008).
[0098] [0098] Particularly in the case of fresh meat packaging, double-coated film comprising an oxygen-permeable inner covering film and an oxygen-impermeable outer covering film are advantageously used. The combination of these two films significantly prevents the discoloration of the meat also when the packaged meat extends upwards with respect to the height of the tray walls, which is a more critical situation in the fresh meat barrier packaging. These films are described, for example, in EP1848635 and EP0690012, the descriptions of which are hereby incorporated by reference. In some instances, the double-coated film can be formed by sealing two suitable films in the corner region by means of very small connection or sealing points. In this way, the double-coated film can be more easily manipulated at different stages of the packaging process.
[0099] [0099] The covering film can be monolayer. The typical composition of monolayer films comprises polyesters, as defined herein, and mixtures thereof, or polyolefins, as defined, and mixtures thereof.
[0100] [00100] In all film layers described herein, the polymer components may contain appropriate amounts of additives normally included in such compositions. Some of these additives are preferably included in the outer layers or in one of the outer layers, while some others are preferably added to the inner layers. These additives include slip and anti-blocking agents, such as talc, waxes, silica and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, cross-linked inhibitors, cross-linked stimulators, UV absorbers, odor absorbers, eliminated - oxygen resins, bactericides, antistatic agents, antifogging agents or compositions, and similar additives known to those skilled in the art of packaging films.
[0101] [00101] Films suitable for coating applications can advantageously be perforated in order to allow the packaged food to breathe.
[0102] [00102] These films can be perforated with the use of different technologies available in the technique, through laser or mechanical means, such as rolls provided with different needles.
[0103] [00103] The number of perforations per unit area of the film and its dimensions affect the permeability of the film to gas.
[0104] [00104] Microperforated films are generally characterized by an OTR value (rated at 23 ° C and 0% R.H. according to the ASTM D-3985 standard) from 2500 cm3 / (m2diaatm) to 1000000 cm3 / (m2diaatm).
[0105] [00105] Macroperforated films are generally characterized by OTR (rated at 23 ° C and 0% R.H. according to ASTM D-3985) higher than 1000000 cm3 / (m2diaatm).
[0106] [00106] In addition, the films described here for coating applications can be formulated to provide a resistant or detachable seal on the support. A method of measuring the strength of a detachable seal, referred to herein as "detachment force", is described in the ASTM F-88-00 standard. Acceptable release force values are provided in the range of 100 g / 25 mm to 850 g / 25 mm, from 150 g / 25 mm to 800 g / 25 mm, from 200 g / 25 mm to 700 g / 25 mm.
[0107] [00107] The desired sealing resistance is achieved specifically by designing the tray and cover formulations.
[0108] [00108] In general, one or more layers of the covering film can be printed in order to provide useful information for the consumer, a pleasant image and / or trademark or other advertising information to enhance the retail sale of the packaged product . The film can be printed by any suitable method, such as rotating screen, engraving or flexographic techniques, as known in the art. DEFINITIONS AND CONVENTIONS RELATING TO MATERIALS
[0109] [00109] PVDC is any vinylidene chloride copolymer where a major amount of the copolymer comprises vinylidene chloride and a minor amount of the copolymer comprises one or more unsaturated monomers copolymerizable with the same, typically vinyl chloride, and alkyl acrylates or methacrylates ( for example, methyl acrylate or methacrylate) and mixtures thereof in different proportions. Generally, a PVDC barrier layer will contain plasticizers and / or stabilizers, as known in the art.
[0110] [00110] As used herein, the term EVOH includes saponified or hydrolyzed ethylene-vinyl acetate copolymers, and refers to ethylene / vinyl alcohol copolymers having an ethylene comonomer content preferably comprised from about 28 to about 48 mol%, more preferably, from about 32 to about 44 mol% of ethylene, and even more preferably, a degree of saponification of at least 85%, preferably at least 90%.
[0111] [00111] The term "polyamides", as used here, is intended to refer to both homopolyamides and copolyamides or ter-polyamides. This term specifically includes aliphatic polyamides or copolyamides, for example, polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 69, polyamide 610, polyamide 612, copolyamide 6/9, copolyamide 6/10, copolyamide 6/12, copolyamide 6 / 66, copolyamide 6/69, aromatic and partially aromatic polyamides or copolyamides, such as polyamide 6I, polyamide 6I / 6T, polyamide MXD6, polyamide MXD5 / MXDI, and mixtures thereof.
[0112] [00112] As used herein, the term "copolymer" refers to a polymer derived from two or more types of monomers, and includes terpolymers. Ethylene homopolymers include high density polyethylene (HDPE) and low density polyethylene (LDPE). Ethylene copolymers include ethylene / alphaolefin copolymers and unsaturated ester ethylene copolymers. Ethylene / alphaolefin copolymers generally include copolymers of ethylene and one or more selected co-monomers of alphaolefins having from 3 to 20 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl -1-pentene and the like.
[0113] [00113] Ethylene / alphaolefin copolymers generally have a density in the range of about 0.86 to about 0.94 g / cm3. The term "linear low density polyethylene" (LLDPE) is generally understood to include that group of ethylene-alphaolefin copolymers that are within the density range of about 0.915 to about 0.94 g / cm3 and particularly about 0.915 to about 0.925 g / cm3. Linear polyethylene in the density range of about 0.926 to about 0.94 g / cm3 is sometimes referred to as linear medium density polyethylene (LMDPE). Lower density ethylene / alphaolefin copolymers can be referred to as very low density polyethylene (VLDPE) and ultra low density polyethylene (ULDPE). Ethylene / alphaolefin copolymers can be obtained by heterogeneous or homogeneous polymerization processes.
[0114] Another suitable ethylene copolymer is an ethylene / unsaturated ester copolymer, which is the ethylene copolymer and one or more monomers of unsaturated esters. Suitable unsaturated esters include vinyl esters of aliphatic carboxylic acids, where the esters have 4 to 12 carbon atoms, such as vinyl acetate, and esters of that of acrylic or methacrylic acid, where the esters have 4 to 12 atoms of carbon.
[0115] [00115] Ionomers are copolymers of an ethylene and an unsaturated monocarboxylic acid having carboxylic acid neutralized by a metal ion, such as zinc, or, preferably, sodium.
[0116] [00116] Useful propylene copolymers include propylene / ethylene copolymers, which are propylene and ethylene copolymers having a majority weight percentage content of propylene, and propylene / ethylene / butene terpolymers, which are propylene, ethylene and 1 copolymers. -butene.
[0117] [00117] As used herein, the term "polyolefin" refers to any polymerized olefin, which may be linear, branched, cyclic, aliphatic, aromatic, substituted, or unsubstituted. More specifically, included in the term "polyolefin" are olefin homopolymers, olefin copolymers, olefin copolymers and a non-olefinic comonomer copolymerizable with olefin, such as vinyl monomers, modified polymers thereof, and the like. Specific examples include polyethylene homopolymer, polypropylene homopolymer, polybutene homopolymer, ethylene-alpha-olefin copolymer, propylene-alpha-olefin copolymer, butene-alpha-olefin copolymer, unsaturated ethylene-ester copolymer, ethylene-unsaturated acid copolymer (for example, unsaturated acid, eg unsaturated acid copolymer) , ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-methacrylic acid copolymer), ethylene-vinyl acetate copolymer, resin resin ionomer, polymethylpentene, etc.
[0118] [00118] The term "polyester", as used here, refers to both homopolyesters and copolyesters, where homopolyesters are defined as polymers obtained from the condensation of a dicarboxylic acid with a diol and copolyesters are defined as polymers obtained from the condensation of one or more dicarboxylic acids with one or more diols. Suitable polyester resins are, for example, ethylene glycol polyesters and terephthalic acid, i.e., poly (ethylene terephthalate) terephthalate (PET). Preference is given to polyesters which contain ethylene units and include, based on the dicarboxylate units, at least 90 mol%, more preferably at least 95 mol%, of terephthalate units. The remaining monomer units are selected from other dicarboxylic acids or diols. Other suitable aromatic dicarboxylic acids are preferably isophthalic acid, pphthalic acid, 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid. Of cycloaliphatic dicarboxylic acids, mention should be made of cyclohexanedicarboxylic acids (in particular, cyclohexa-no-1,4-dicarboxylic acid). Of the aliphatic dicarboxylic acids, alkanedioic acids (C3-C9) are particularly suitable, in particular, succinic acid, sebacic acid, adipic acid, azelaic acid, subteric acid or pyelic acid. Suitable diols are, for example, aliphatic diols, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, neopentylglycol and 1,6-hexanediol, and cycloaliphatic diols, such as 1,4-cyclohexanedimethanol and 1,4-cyclohexanediol, optionally heteroatom containing diols having one or more rings.
[0119] [00119] Copolyester resins derived from one or more dicarboxylic acids or their diesters thereof (up to 14 carbon atoms) with one or more glycols, particularly an aliphatic or cycloaliphatic glycol, can also be used as the polyester resins for the base film. Suitable dicarboxylic acids include aromatic dicarboxylic acids, such as terephthalic acid, isophthalic acid, phthalic acid, or 2,5-, 2,6-, 2,7-naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids, such as succinic acid, sebacic acid, adipic acid, azelaic acid, submeric acid or pyelic acid. Suitable glycol (s) includes aliphatic (cluem) diols, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl -1,3-propanediol, neopentylglycol and 1,6-hexanediol, and cycloaliphatic diols, such as 1,4-cyclohexanedimethanol and 1,4-cyclohexanediol. Examples of such copolyesters are (i) copolyesters of azelaic acid and terephthalic acid with an aliphatic glycol, preferably ethylene glycol; (ii) copolyesters of adipic acid and terephthalic acid with an aliphatic glycol, preferably ethylene glycol; and (iii) sebacic and terephthalic acid copolyesters with an aliphatic glycol, preferably butylene glycol; (iv) copolyesters of ethylene glycol, terephthalic acid and isophthalic acid. Suitable amorphous copolesters are those derived from an aliphatic diol and a cycloaliphatic diol with one or more dicarboxylic acids, preferably an aromatic dicarboxylic acid. Typical amorphous copolyesters include terephthalic acid copolyesters with an aliphatic diol and a cycloaliphatic diol, especially ethylene glycol and 1,4-cyclohexanedimethanol. DETAILED DESCRIPTION First implementation of the device 1
[0120] [00120] Figures 1-11 show an apparatus for packaging a product P arranged in a support or tray 4 according to an embodiment of the present invention. Apparatus 1 is adapted for packaging in a modified atmosphere, where a plastic film, such as a film sheet 18 described below, is applied to the upper edge 4c of a support or tray 4 after a modified gas atmosphere has been created within the support 4, and / or for vacuum film packaging of product P, where a thin film of plastic material, such as a film sheet 18 described below, is draped downwardly over the product and closely adhered to an upper edge and the surface inside the support as well as the product surface, thus leaving a minimal amount, even any, of modified air or gas inside the packaging. Apparatus 1 can also be used in the case of a sheet of film applied to a tray or support and no vacuum or modified atmosphere is created.
[0121] [00121] The apparatus 1 comprises a frame 2, a transport assembly 3 for moving the support or tray 4, a film supply assembly 5, a film cutting assembly 6, a transfer device 7 and a packaging assembly 8.
[0122] [00122] The tray 4 shown in the attached figures has a base wall 4a, a side wall 4b that emerges from the base wall and delimits a space where a product P can be housed, and an upper edge 4c that protrudes radially from the side wall 4b; in the example shown, the upper lip 4c has a flat horizontal portion that defines a sealing surface suitable for sealing a plastic film.
[0123] [00123] The frame 2 defines a basic body of the device 1 and serves to guide or support various parts of the device 1, as described here.
[0124] [00124] The transport assembly 3 comprises a displacement plane 20 (which can be a physical plane (for example, a conveyor belt) that leads and moves the trays or supports or an ideal plane along which the trays are guided, for example, by means of rails or guides). The plane 20 is defined in an upper area of the frame and a conveyor 46 is arranged in correspondence with the sliding plane 20. In the example shown, the transport assembly 3 is guided by the frame 2, for example, fixed in it, so that the sliding plane 20 is substantially horizontal and the conveyor 46 moves the trays or supports 4 according to the horizontal direction indicated by the arrow A1 shown in Figure 1. The transport assembly 3 arranged on the frame 2 is configured to move the support or tray 4 along a predefined path of a loading station, where the supports or trays 4 that may already be filled with the respective product (s) P are positioned, for the packaging assembly 8 where a sheet of film 18 is tightly attached to each support or tray 4, as explained in detail below. The conveyor 46 moves the trays (for example, a pre-set number of trays at a time) towards and towards the packaging chamber, to the proper position to receive the cut film sheets. For example, a control unit 100 (which is further described below) can control conveyor 46 to move a pre-fixed number of trays or supports 4 at a time from a region outside the packaging assembly to a region within the packaging assembly. packaging where the tray or trays are in vertical alignment with the film sheets (for example, directly below or overlapping them). The conveyor may, for example, include a first transfer device 46a (such as the belt shown in Figure 1) configured to bring the trays in close proximity to the packaging assembly and a second transfer device 46b adapted to collect one or more more of said trays and bring them to the packaging assembly 8. The second transfer device may, for example, include actuators or arms that act on the sides of the trays or holders in such a way as to collect the holders of the first holding device transfer, to bring them to the packaging station, and then to return to the first transfer device to collect a new set of trays or supports 4. Alternatively, conveyor 46 may include impellers (for example, in the form of bars that extend transversal to the said direction A1) that act on the trays and push the trays for the packaging assembly 8. The impellers can be moved by chains or belts and can be moved to the packaging assembly to properly position numerous trays, and then be retracted from the packaging assembly, once the trays have reached their proper position within the packaging assembly. In some instances, impellers can be integrated into the packaging assembly in a way that does not interfere with the process that takes place within the packaging assembly. In these examples, the impellers are extended in order to retrieve numerous trays and move them to the packaging assembly, in which the impellers are fully retracted and where they subsequently remain until the packaging assembly is opened after the execution of the process that takes place inside. packing assembly. According to an additional alternative, the conveyor 46 may include housings (for example, in the form of plates provided with cavities for receiving numerous trays) which are moved along said direction A1 and which are movable within the packaging station together with the supports or trays 4. According to this alternative, the housings have a suitable shape in order to be accommodated inside the packaging station during the application of the film 10a in the tray or in the support 4.
[0125] [00125] It is noted that the P products can be positioned on the support or in tray 4, either upstream of the loading station, or at any location between the loading station and the packaging assembly 8. The transportation assembly 3 additionally comprises a motor 9 (for example, a stepper motor unit) for operating the conveyor belt 46 with a continuous or stepping motion.
[0126] [00126] The film supply assembly 5 may comprise a roll of film 10 that supplies a continuous film 10a. The film supply assembly 5 may additionally comprise an arm 11 (shown in dashed lines in Figure 1) attached to the frame 2 and suitable for supporting the roll 10. In addition, the film supply assembly 5 may comprise punching devices film (not shown, as these are known in the art) essentially configured to provide the correct profile for the edges of the film to match (when cut transversely in the cut assembly 6) to the shape of the opening of tray 4 with rounded corners. Punching devices can also help to keep an unwound portion of film pulled from the film roll 10 aligned in a pre-fixed direction. The film supply assembly 5 also comprises clamping rollers 12 and / or other means for pulling the film from the roll 10 and properly positioning it in correspondence with the film cutting assembly 6 (for example, said means may comprise clamps that act on the side of the film and / or tweezers that act on an edge of the film (for example, the front edge or the lateral edges) and configured to pull the film).
[0127] [00127] The type of film 10a wound on the film roll 10 and supplied to the device 1 may correspond to one of the types of film described above, depending on the specific application.
[0128] [00128] The film cut assembly 6 shown in the figures is an exemplary cut assembly illustrating one of several alternatives for supplying film sheets 18. In general, film sheets 18 could be pre-cut at another location and provided in the form of stacks of film sheets 18 ready for heat sealing. In addition, the film sheets 18 can be cut locally, for example, by a cutting assembly (such as cutting assembly 6) located external to the packaging chamber. In both cases, the film sheets 18, whether pre-cut or cut online, are supplied to the packaging apparatus 1 by a corresponding transfer device which collects the film sheets 18 and transfers them to the packaging chamber 24 or some component of the packaging apparatus (for example, a retaining plate, such as the retaining plate 36) is driven to an operating position within the packaging assembly or packaging chamber in order to properly position the packaging sheet. film 18 to be heat sealed on a support 4. As an additional alternative, the cutting assembly can be located within the packaging assembly in such a way that the film sheets 18 are instantly cut and collected by a component (for example, a sealing head or a retaining plate) directly inside the packaging assembly or the packaging chamber, in such a way that the film sheets 18 do not need to be transferred to the packaging assembly packing chamber (in which case no separate transfer device is required). It is noted that the individual manner in which the film sheets 18 are supplied can be carried out according to any of the mechanisms described above or any other suitable method.
[0129] [00129] The film cutting assembly 6 comprises a cutting device 13 with a blade 14 and a blade piston 15. This piston 15 can be replaced by any type of (linear) electric, pneumatic or hydraulic actuator. The blade piston 15 is preferably attached to the frame 2 and is connected to the cutting device 13 in order to push and pull it in a direction transverse to the uncoiled portion of the film 10a, as indicated by the double arrow A2 shown in Figure 1. The film cut assembly 6 is described here, illustrating a possibility of supplying the film to the packaging device. In some instances, however, the film material can be supplied in a manner where the film is pre-cut and supplied, for example, on a sheet-by-sheet basis, dispensed from a stack of pre-cut sheets of film.
[0130] [00130] Figures 2 to 11 show a more detailed view of the transfer device 7 and the packaging assembly 8 of the packaging apparatus 1 according to a first embodiment.
[0131] [00131] In general, the packaging assembly 8 is configured to tightly secure the film sheets 18 to said supports 4 and includes a lower tool 22 and an upper tool 21. The lower tool 22 has numerous internal walls 23 that define a pre-fixed number of seats 23b. In one embodiment, the lower tool 22 is provided with multiple seats 23b, each to host a corresponding support 4. In this case, the upper tool 21 is provided with a corresponding plurality of retaining plates 36, each to retain a respective sheet. of film 18.
[0132] [00132] Each of the seats 23b is configured to receive a support 4. For example, in the embodiment of Figures 2-11, the seat 23b is peripherally bounded by the inner wall 23 and the support or tray 4 is received inside the seat 23b such that the upper edge 4c can be supported above the end surface 23a of the inner wall 23. The upper tool 21 faces the lower tool 22 and is configured to retain one or more of said film sheets 18; in the example shown in Figures 2-11, the upper tool 21 is configured to retain a cut film sheet 18. As shown in Figures 2-11, the upper and lower tools 21, 22 cooperate to define a packaging chamber 24. In a first operating condition of the packaging assembly 8 - shown in Figures 2-6 and 11 - the upper and lower tools 21 and 22 are spaced apart and the packaging chamber 24 is opened, thus allowing one or more of the said film sheets 18 move from the cutting assembly 6 to the packaging chamber 24, as further detailed below. In a second operating condition of the packaging assembly 8 - shown in Figures 7-10, the packaging chamber 24 is hermetically closed with respect to an atmosphere outside the apparatus 1.
[0133] [00133] It is noted that, within the scope of this document, the term "hermetically sealed" indicates that the inside of the packaging chamber 24 cannot communicate freely with the atmosphere outside the chamber and the gas can be supplied or removed from the chamber only via supply or discharge channels under the control of the device 1.
[0134] [00134] The aforementioned transfer device 7 is configured to position the cut film sheets 18 within the packaging chamber 24 and above the respective support 4. The transfer device 7 includes a support structure 16 having a flat retaining surface 17 adapted to receive at least one or more sheets of film 18 cut by the blade 12. While the support structure 16 is described here and shown in the figures as having a substantially flat retention surface 17, it is noted that the retention surface 17 does not it has to be flat, but it can have any suitable shape (for example, concave, convex, corrugated, showing some texture, showing protrusions and / or recesses, etc.). Figure 1 shows that the blade 14 is configured to cut the continuous film 10a in such a way that a separate film sheet 18 can be positioned in correspondence with the flat retention surface 17. The support structure 16 can retain the film sheet cut 18 using one or more of the following:
[0135] [00135] - a vacuum system connected to one or more channels present in the support structure and leading to openings located on the retaining surface 17,
[0136] [00136] - mechanical supports, such as tweezers, clamps or similar,
[0137] [00137] - adhesive systems, for example, comprising adhesive portions associated with the retention surface 17,
[0138] [00138] - heating systems, for example, comprising heatable portions (controlled by the control unit 100) associated with the support structure that cause heating of the retention surface 16 and, therefore, of the film sheet 18 in order to increase the adhesiveness of the film sheet to the retention surface 17,
[0139] [00139] - electrical systems, for example, the retaining surface can be charged with a different polarity than that typical of the plastic sheet 18. In this case, the control unit can be connected to a voltage generator and can control the electrical loading of the surface 17.
[0140] [00140] In the embodiments shown in Figures 2 to 17, the support structure 16 is shown to employ a vacuum system that is configured to create negative pressure on the side of the flat retention surface 17 with the evacuation of air or gas through the channels 16a (shown in Figure 2) present in the support structure 16, channels 16a defining openings located on the flat retention surface 17. Again, while the support structure 16 and the retention surface 17 are described here and shown in the figures as being substantially flat, it is noted that the respective elements could have any suitable non-flat shape (for example, concave, convex, with some texture, showing protrusions and / or recesses, etc.). The channels 16a, schematically shown in Figures 2 to 17, and / or the corresponding openings can be arranged, sized and / or formed in a manner suitable for the given application and depending on the material or type of film 10 used. For example, the size, shape and number, as well as the individual distribution of channels 16a over the area of the support structure 16 can be adapted, as desired. For thicker, more resistant and / or heavier film materials, for example, channels 16a and / or corresponding openings may be larger in size (for example, larger in diameter) and / or distributed more densely, whereas , for thinner, weaker and / or lighter file materials, channels 16a and / or corresponding openings may be smaller in size (for example, a smaller diameter) and / or be distributed more sparingly.
[0141] [00141] Channels 16a are in fluid communication with a suitable vacuum source or evacuation medium (not shown), as known in the art. In addition to the type and distribution of channels and / or openings, the vacuum source or the evacuation medium can be controlled appropriately for the individual film materials used, in a manner known in the art. For the sake of clarity, additional individual components known in the art, for example, the vacuum source or evacuation medium, piping, connection channels, lines, valves, etc., are not shown in all figures.
[0142] [00142] The transfer device 7 also includes a mechanism, for example, driven by the frame 2, active in the support structure 16 and configured to relatively move the support structure 16 with respect to the packaging assembly 8 between a first position, shown in Figure 2, where the support structure 16 is positioned close to the cutting device, for example, immediately downstream of the blade 14 with respect to the movement imposed on the film 10a, and at least a second position, where the support structure 16 is positioned within the packaging chamber 24. In the examples shown in the attached figures, the mechanism includes a transfer actuator 47a active on the support structure 16 via a side support 47b and configured to move the support structure 16 along a suitable path to achieve the displacement between said first and second positions. It is noted that, for the sake of clarity, the transfer actuator 47a and side support 47b are not shown to scale in the figures, but merely illustrate the possibility of a rotary actuator, giving movement to the support plate 17 between a retracted position, where the backing plate can collect sheets of film 18, and a transfer position, where the backing plate can supply sheets of film 18 for packaging assembly. For example, the transfer mechanism and actuator can move and rotate the support structure along a circular path, as indicated by the dashed arrow in Figure 3. The rotation range of the transfer actuator 47a is configured in such a way that the the support structure can position at least one sheet of film 18 above said support 4 inside the chamber 24, below and / or in superposition with a central portion of the upper tool 21, as shown in Figure 3. The transfer actuator 47a can be any type of electric, pneumatic or hydraulic actuator known in the art and suitable for operating the support structure in the required manner. For the sake of clarity, the transfer mechanism and / or transfer actuator 47a and side support 47b are not shown in all figures.
[0143] [00143] As an alternative, instead of moving the support structure 16, the upper tool 21 can be movable with respect to the frame 2 and be configured to pick up the cut film sheets 18 from the area immediately downstream of the cutting device 13 In this case, the transfer device 7 would include a mechanism 25, for example, driven by the frame 2, active in the packaging assembly 8 and configured to move the upper tool 21 between a first position, where the upper tool 21 is positioned in correspondence with the support structure 16 and configured to collect from the support structure 16 one or more cut film sheets 18, and at least a second position, where the upper tool 21 is aligned with respect to the lower tool 22 and configured to position at least one sheet of film 18 above said support 4. In order to achieve the above movement, the mechanism can move the upper tool 21 along any suitable path. For example, Figure 1 schematically shows that the mechanism 25 can include a transfer actuator 26 configured to move the upper tool 21 along a direction parallel to said horizontal direction A1, as indicated by the double arrow A4 in Figure 1, as well as to rotate the upper tool 21 so that its lower end faces the support structure 16 in order to collect the film sheets 18. Alternatively, the mechanism 25 can exclusively cause the upper tool to rotate about an axis pivoting or translational displacement in order to move the upper tool between the respective positions. The transfer actuator 26 can comprise any type of electric, pneumatic or hydraulic actuator or combinations thereof known in the art. Figure 1 illustrates both mechanisms described above.
[0144] [00144] The apparatus 1 also includes at least one control unit 100, which is connected to the transport assembly 3, the film supply assembly 5, the film cut assembly 6, the transfer device 7 and the assembly of packaging 8. The control unit 100, which is schematically shown in Figure 1, is configured to activate the transfer device 7 in order to control the movement of the support structure 16 (or the upper tool 21, as described above), to the different operating positions described above. The control unit 100 is also configured to synchronize the activation of the transfer device 7 with the passage of the packaging assembly 8 from the first to the second operating condition so that the movement of the support structure 16 takes place when the packaging chamber 24 is open while the packaging chamber 24 is closed. only once the support structure 16 has transferred the cut film sheet 18 to the upper tool 21 and has been retracted from the packaging chamber 24. The control unit can also be configured to synchronize the conveyor 46 in such a way that the moving a pre-fixed number of trays or supports 4 from a region outside the packaging chamber 24 to a region inside the packaging chamber 24 happens when the packaging chamber 24 is open while the packaging chamber 24 is closed, only once said pre-fixed number of trays or supports 4 is in the appropriate position with respect to the upper tool 21.
[0145] [00145] Apparatus 1 may also comprise a vacuum arrangement 27 connected to the packaging chamber 24 and configured to remove gas from said packaging chamber. The vacuum arrangement comprises at least one vacuum pump 28 and at least one evacuation tube 29 that connects the inside of said chamber 24 to the vacuum pump. The control unit 100 controls the vacuum pump 28 to draw gas from said packaging chamber 24 at least when the packaging assembly is in said second operating condition, that is, with said packaging chamber hermetically closed. Apparatus 1 may additionally or alternatively include a controlled atmosphere arrangement 30 connected to the packaging chamber 24 and configured to inject a gas flow into said packaging chamber, the controlled atmosphere arrangement comprising at least one injection device including a pump injection valve and / or an injection valve 31 that act on at least one injection tube 32 that connects the inside of said chamber to a controlled gas source (not shown) that can be disposed external to the device 1. The unit control valve 100 can be configured to control the opening and closing of the injection valve (or the activation of the injection pump) 31 to inject said controlled gas flow at least when the balloon assembly 8 is in said second condition of operation, that is, with said packing chamber 24 hermetically closed.
[0146] [00146] The control unit 100 can also be configured to control the composition of the modified atmosphere generated within the chamber 24. For example, the control unit 100 can regulate the composition of the flow of gas injected into the packaging chamber. Mixtures of gases injected into the packaging chamber to generate a modified atmosphere may vary depending on the nature of the product P. In general, mixtures of a modified atmosphere include a volumetric amount of one or more of N2, O2 and CO2 that differs from the amount of the same. gases, as present in the atmosphere at 20 ° C and at sea level (1 atmospheric pressure). If product P is a product, such as meat, chicken, fish, cheese, cooked food, or pasta, the following gas mixtures can be used (quantities are expressed as percentages of volume at 20 ° C, 1 atm of pressure) :
[0147] [00147] - Red meat, skinless chicken: O2 = 70%, CO2 = 30%
[0148] [00148] - Chicken with skin, cheese, pasta, cooked food: CO2 = 50%, N2 = 50%
[0149] [00149] - Fish: CO2 = 70%, N2 = 30% or CO2 = 40%, N2 = 30%, O2% = 30
[0150] [00150] - Processed meat: CO2 = 30%, N2 = 70%
[0151] [00151] According to one aspect, the control unit 100 can be configured to control said injection pump or said injection valve 31 to start the injection of said controlled gas flow, either after a pre-fixed delay activation of said vacuum pump 28 or after a pre-set level of vacuum has been reached inside said packaging chamber 24. In an additional aspect, the control unit 100 can cause the injection of said gas flow controlled to create a modified atmosphere while said vacuum pump 28 is still active in order to shorten the time to create the modified atmosphere. It is noted, however, that the high oxygen content in the evacuated and / or supplied or otherwise processed gases can carry a substantial risk of explosion in some of the components (for example, the pump or pumps). Consequently, suitable components must be used. In addition, since it is preferable to prevent a very strong vacuum in the packaging chamber 24 and at the same time it is desirable to ensure a suitable atmosphere within the chamber, it is advantageous to stop the vacuum pump after opening the gas injection. In this way, the pressure inside the packaging chamber can be controlled in order not to drop below a desired value. During the simultaneous operation of the vacuum pump 28 and the injection of said controlled gas flow, the injected gas is mixed with residual air and the vacuum pump 28 continues to remove the mixture so that the amount of gas and / or air initially present in the packaging chamber is continually decreased. This gas discharge and the mixture of gas and residual air are very important in order to achieve the desired controlled atmosphere in an effective and efficient manner, while ensuring that the desired pressure (ie, the vacuum level) is obtained.
[0152] [00152] In accordance with an additional aspect, it is noted that the control unit 100 is configured to control said injection pump 31 in such a way that the gas flow is not injected at a speed that is too high and that can impair the firm retention of the cut film by the upper tool. The control unit 100 can control the gas injection at a gas pressure set below a limit to prevent the film from shedding from the upper tool 21 or imprecise positioning of the film in correspondence with the upper tool 21. In one example, the injection pressure is maintained between 0.13 and 0.4 MPa (1.3 and 4.0 bar), or preferably between 0.15 and 0.3 MPa (1.5 and 3.0 bar).
[0153] [00153] It is noted that, in the examples shown, the evacuation tube 29 and the injection tube 32 communicate with a lower portion of the packaging chamber that is separated from an upper portion of the packaging chamber due to the presence of said wall or inner walls 23 that define a type of separation septum. In order to allow adequate gas circulation within the entire packaging chamber, the upper and lower portions of the packaging chamber 8 are fluidly connected by openings or channels located in the vicinity or on the inner wall 23. These openings or channels (see, for example, Figures 3-5) are positioned in such a way that they are not obstructed by the walls of the tray when the tray is positioned on seats 23b.
[0154] [00154] Although the apparatus 1 may have the vacuum arrangement 27 or the controlled atmosphere arrangement 30, or both, it will be understood that the control unit 100 of the apparatus 1 may also be configured to tightly engage the film sheets 18 with the trays without activating the vacuum arrangement or the controlled atmosphere arrangement, thus leaving the normal ambient atmosphere inside the tray. This may, for example, be the case for non-perishable products. In another embodiment, the apparatus 1 can be designed without the vacuum arrangement and the modified atmosphere arrangement.
[0155] [00155] Now entering into a more detailed description of the packaging assembly 8, it will be noted that this additionally comprises a main actuator 33 active in at least one of said upper and lower tools 21 and 22. In the example of Figures 2-11, the first actuator 33 is driven by frame 2 and acts on the lower tool 22 under the control of the control unit 100. The main actuator 33 can include a piston (the piston can be replaced by any type of (linear) electric, pneumatic or hydraulic) configured to raise and lower the lower tool 22 along a direction transverse to said horizontal direction A1. In the example in Figures 1-16, the lower tool can be raised and lowered vertically by the main actuator 33, as indicated by the double arrow A5 shown in Figure 1. The control unit 100 is configured to control the main actuator 33 and to cause the movement of the lower tool 22, along the pre-fixed main direction indicated by the arrow A5, between said first operating condition (Figures 2 to 6), where the upper tool 21 is spaced from the lower tool 22 and said chamber packaging 24 is opened to receive one or more of said sheets of film 18, and said second operating condition (Figures 7 to 10), where a closing surface 34 of the upper tool 21 seals against a closing surface 35 of the lower tool 22 to tightly close said packaging chamber 24 with respect to an atmosphere outside the apparatus. A gasket or other element to facilitate a gas-tight closure can be positioned on said closing surfaces 34 and 35. As mentioned above, the control unit synchronizes the opening and closing of the packaging chamber with the movement of the support structure 16 .
[0156] [00156] Once the chamber 24 has been closed, and after the operation of the vacuum arrangement and / or the controlled atmosphere arrangement, the control unit is configured to act on the main actuator 33 to impose an additional vertical movement to the lower tool and therefore also the upper tool, since it now rests against the lower tool (Figure 9), in such a way that the film sheet 18 is brought into contact with the edge 4c of tray 4. It is noted that the elastic elements 55 can be interposed between the upper tool and the frame (such as one or more compression springs and / or one or more pneumatic actuators) to elastically push the upper tool against the lower tool.
[0157] [00157] It is also noted that each seat 23b operates at least one internal element 50, which, in the apparatus of Figures 1-16, includes a rod 51 and an end plate 52, configured to hold at least the base 4a, the tray or support 4. The inner element is movable with respect to the lower tool 22 at least along the main direction of the direction of the double arrow A5. In the shown embodiment (see, for example, Figure 2), the rod 51 can slide through an opening 53 in the bottom 54 of the lower tool 22 in order to allow the relative movement between said inner element 50 and the lower tool 22. It is noted that the internal element can be controlled by a respective actuator (not shown) or can be directly guided by frame 2. In the examples shown, in the case where the lower tool is movable up and down, as described above, the element The inner element 50 can remain vertically fixed at least until the end plate reaches the bottom 54 of the lower tool (see Figures 7-10), in which case the inner element 50 is configured to move further upwards along with the bottom 54 of the tool. bottom tool and optionally driven by it.
[0158] [00158] In additional details, the upper tool 21 has at least one retaining plate 36 having a respective active surface 37 configured to receive one or more sheets of film 18 and a means 38 to retain one or more sheets of film 18 in correspondence with said active surface 37. The retention means 38 may comprise a vacuum source 39, for example, in the form of a pump, controlled by the control unit 100 and connected to a plurality of suction holes 48 present in correspondence with the active surface 37. The control unit 100 can be configured to activate the vacuum source 39 and cause the film retainer plate 36 to receive and retain one or more sheets of film 18 in correspondence with the active surface 37. In In particular, the control unit 100 can be configured to coordinate the activation of the vacuum source 39 with proper positioning of the cut film sheet 18 by the backing plate 16. For example, the joint of control 100 can activate the vacuum source 39 and cause the film retainer plate 36 to receive and retain said film sheets 18 or more in correspondence with the active surface 37, when the support structure 16 leading the cut film 18 is properly positioned within the packaging chamber below the retaining plate 36. It is noted that, in addition to or alternatively to the vacuum source 39, the retaining means 38 may include one or more of the following:
[0159] [00159] - mechanical supports, such as tweezers, clamps or similar,
[0160] [00160] - adhesive systems, for example, comprising adhesive portions associated with the active surface 37,
[0161] [00161] - heating systems, for example, comprising heatable portions - controlled by the control unit 100 - associated with the retaining plate to cause heating of the active surface 37 and, therefore, of the film sheet 18 in order to increase adhesiveness from the film sheet to the active surface 37,
[0162] [00162] - electrical systems, for example, the active surface 37 can be charged with a different polarity than that typical of the plastic sheet 18. In this case, the control unit can be connected to a voltage generator and can control the electrical loading of the surface 37.
[0163] [00163] Similar to the lower tool 22 and the controlled atmosphere arrangement 30, the upper tool 21 may comprise or be connected to a film positioning arrangement 30a, which comprises an injection device 31a similar to the injection device 31, as described above. The injection device 31a is configured to selectively supply a flow of pressurized air or gas 31b (see, for example, Figure 6A) to the retainer plate 36 and is connected to a plurality of ejectors 36c present on the retainer plate 36 in in a similar manner, since the vacuum source 39 is connected to the suction ports 48, as described above. The air or gas supply can be controlled via the control unit 100, which can be configured to control, for example, a corresponding valve (or valves)). Alternatively or in addition, the control unit 100 can be configured to control the activation of the injection device 31a (for example, starting, stopping, increasing or decreasing its activity, intermittent pulses, etc.). The injection device 31a is additionally connected to a suitable source of air or gas, as indicated by the dashed line in Figure 2. For clarity, all individual connections, channels, pipes and / or valves, etc. they are not shown in Figure 2. It is understood that such connections are known in the art and can be adapted for the respective purpose (for example, supply of pressurized air / gas or a vacuum).
[0164] [00164] As mentioned above, the retainer plate 36 comprises a plurality of ejectors 36c disposed on the sides and / or corners of the retainer plate 36. Figure 2, for example, shows a cross-sectional view of the retainer plate 36 to the along a plane perpendicular to the plane of the active surface 37 (see dashed line II in Figure 6C). In the example shown in Figure 2, the ejectors 36c are arranged on both side sides of the retaining plate 36 in such a way that also a cross section of the ejectors 36c is shown. It is understood that, in this example, additional ejectors 36c are also arranged on the front and rear sides of the retaining plate 36. Preferably, the ejectors are placed along the edge region in such a way that the ejectors 36c are arranged along the entire length. periphery of the retainer plate 36 and evenly spaced from each other (for example, the ejectors are spaced at the same distances from each other around the retainer plate 36). In general, the side walls of the retainer plate 36 define a side surface thereof, which is substantially perpendicular to the active surface 37 of the retainer plate 36. The retainer plate 36 typically has, as seen from the top (see, for example, example, Figure 6C) is generally rectangular in shape, while the side surface delimits the perimeter of the retainer plate 36 in all directions as it extends around the entire periphery of the retainer plate 36.
[0165] [00165] Figure 6C shows a cross-sectional view of an exemplary arrangement of ejectors 36c on the retaining plate 36. Here, a cross-sectional view along a plane parallel to the active surface 37 is shown. In this example, the ejectors 36c are substantially evenly spaced from each other, whereas one of the ejectors 36c is arranged at each corner of the retaining plate 36 and three ejectors 36c are arranged on each side of the retaining plate 36c, such that the plate retainer 36 has 16 ejectors in total. It is understood that, in general, the retainer plate 36 can comprise any number of ejectors depending on the individual application (for example, depending on the material used for the film sheet 18 or the dimensions and / or the shape of the retainer plate 36) . In some embodiments, the retaining plate 36 may comprise 8, 12, 16, 20, 24 ejectors. It is further understood that the ejectors can be uniformly arranged around the retaining plate 36 or in an irregular manner, where, for example, the distances between the ejectors 36c are different and / or where one side has more ejectors 36c than the other side of the retainer plate 36. In some examples, the ejectors 36a are placed more concentrated in the corner regions of the retainer plate 36. In addition, the retainer plate may have a rectangular cross-sectional shape than a substantially square shape, as shown in Figure 6C. In such cases, the numerous ejectors 36c arranged on the longer sides of the retaining plate 36 can be larger than the numerous ejectors 36c arranged on the shorter sides of the retaining plate 36, regardless of whether the ejectors 36c are uniformly arranged with each other.
[0166] [00166] Figure 6C additionally shows an exemplary piping arrangement comprising a channel 36d, peripherally extending around the retaining plate 36 and in fluid communication with the ejectors 36c. The injection device 31a can be connected to channel 36d in any suitable manner in such a way that the flow of air or gas 31b can be supplied to the ejectors 36c. The piping arrangement 36d is preferably configured in such a way that the flow of air or gas 31b can be substantially uniformly supplied to the ejectors 36c arranged around the retaining plate 36.
[0167] [00167] With reference now to Figure 6A, each ejector 36c is arranged and formed in such a way as to facilitate the ejection of a flow of air or gas 31b in a substantially parallel manner with respect to the plane of the active surface 37 such that the air or gas flow 31b is configured to flow from the retaining plate 36 close to the plane defined by the active surface 37 in a direction substantially parallel to it, in particular, having a major movement component substantially parallel to said plane. It is noted that the flow of air or gas 31b presents, with the exit of an ejector 36c, essentially an unlimited number of components of movement, due to the turbulence that occurs in and around the ejector 36c, regardless of the presence of gas or vacuum in the environment inside the chamber 24. In the context of the present description, the term "main movement component" is defined as the main direction of the air or gas flow 31b with the ejector outlet 36c, which is composed of many movement components very similar that eventually deviate more and more from the initial direction that the air or gas flow 31b has while it is still inside the ejector 36c. Such deviation increases with the distance of the ejector 36c after the air or gas flow 31b leaves it. Within the context of the present description, an air or gas flow 31b will have a major movement component parallel to the plane of the active surface 37, if the main direction of the air or gas flow does not change substantially before the air or gas flow has a distance traveled substantially corresponding to the lateral extension of the heating surface 41 and / or substantially corresponding to the width of the cut film 18 that extends beyond the retaining plate 36 (see Figure 6A).
[0168] [00168] At least some or all of the ejectors 36c are additionally arranged in proximity to the active surface 37, preferably being spaced from the heating surface 41 of the heating structure 40 by a distance that is greater than that of the active surface 37. In In general, the ejectors 36c can be arranged in any suitable manner to ensure an unobstructed ejection of air or gas 31b from the retainer plate 36 when the retainer plate 36 and the heating structure 40 are in a spaced configuration, as shown in Figures 2 or 6A. This spaced-apart configuration is defined in contrast to a configuration in which the heating structure 40 will essentially house the retaining plate 36, when the position of the retaining plate 36 has been displaced, as shown in Figure 10, in which some or all ejectors 36c are blocked by heating structure 40.
[0169] [00169] Ejectors 36c can be configured, sized and / or appropriately formed to facilitate the ejection of a flow of air or gas 31b substantially parallel to the active surface 37, as shown in Figures 6, 6a and 7 to 9. For example, ejectors 36c may have a substantially cylindrical shape (e.g., a regular tube shape; the corresponding openings being substantially circular), as shown in Figures 2 to 17. Alternatively, ejectors 36c may have a tapered shape ( for example, conical; the diameter increasing, either outward or inward), an elliptical shape (for example, a flattened cylinder), a slit shape (for example, vertical or horizontal slit), a combination of those mentioned above, or any other way that allows air or gas to be ejected substantially parallel to the active surface 37.
[0170] [00170] As can be seen, for example, from Figures 6A and 6C, the ejectors 36c define a channel that opens into the space around the retaining plate 36 in such a way that the ejected air or gas flows 31b by the ejectors 36c can enter said space and be dispersed, preferably evenly, around the retaining plate 36. Figures 5 to 9 show that the air or gas flows 31b ejected from the ejectors 36c can leave the retaining plate 36 in a largely unrestricted manner and air or gas can escape from chamber 24 when they are in the open configuration, or be dispersed throughout the chamber 24 when they are in the closed configuration. In general, the ejectors can have any suitable shape that allows for the ejection and flow of gas, as desired in the context of the present invention. In this way, the ejector properties shown here can be modified for some applications. In some examples, the ejectors exhibit an inclination, either upward or downward, that is, away from the film retained by or in the direction of the retention plate. Other properties can also vary, for example, diameter, size, orientation, etc., as also further described below.
[0171] [00171] As further discussed below, when describing the operation of the device 1, the control unit can be configured to create a vacuum in the packaging chamber 24 (with the control of the vacuum pump 28 to remove the gas from said chamber) packaging 24) until a pressure between 100 and 300 mbar, optionally between 150 and 250 mbar, is reached. This pressure level is low enough, but not too low so that the film sheet from the retention plate 36 is prevented, as the control unit also creates a pressure level in correspondence with the suction holes 48, with action on the vacuum source 39, below the pressure level in the packaging chamber.
[0172] [00172] As shown in Figures 2-11, the balloon assembly 8 has a heating structure 40 peripherally associated with the film retaining plate 36 and having a respective heating surface 41 that extends radially on the outside with relative to the active surface 37 of the retainer plate 36. In practice, the retainer plate 36 is sized to cover only a central portion 18a of the cut film sheet 18 while the heating surface 41 of the heating structure 40 is designed to heat a peripheral portion 18b of the cut film sheet 18 surrounding said central portion. The term "peripheral portion", as used herein, generally indicates the portion or portions of the cut film sheet 18 that comprise one or more edge regions or optionally one or more corner regions, as well as part of the adjacent film material (e.g. example, a region including between about 3 mm to about 10 mm (preferably between about 4 mm to about 8 mm) of material around the edges of the cut film sheet 18). The peripheral portion 18b may be continuous (for example, comprising all edges and corners) or not continuous (for example, comprising only one or more edges without the corners). The packaging assembly 8 and particularly the heating structure 40 are positioned and configured in such a way that at least when the packaging assembly 8 is in said second operating condition, the heating surface 41 of the heating structure 40 will face the end surface 23a of said inner wall 23 that delimits one of said seats 23b in the lower tool 22. It is noted that, in the example of Figures 2-11, the heating structure 40 and the film retaining plate 36 are initially positioned such that the heating surface 41 is retracted with respect to the active surface 37 (see Figures 2-6). This ensures that, in this initial relative position of the heating structure 40 and the retaining plate 36, the ejectors 36c are not covered by the heating structure 40 (see above) As described, and as can be seen, in particular, from the series of Figures 9, 10 and 11, also the heating structure 40 and the retaining plate 36 are relatively mobile with each other along said main (vertical) direction represented by the double arrow A5. In detail, the retaining plate 36 is terminally driven by a shaft 36a slidably coupled with respect to the heating structure 40 and having a back portion 36b designed to cooperate with the upper tool and the heating structure, as explained below. An elastic element 60 (which can be, for example, a spring or a pneumatic actuator) can be interposed between the retaining plate and the heating structure. The elastic element 60 allows the positioning of the retaining plate 36, as shown in Figures 2-9, since the elastic element 60 tends to push the retaining plate down (the downward stroke of the retaining plate 36 with respect to the structure heating element 40 is limited by the stop portion 36a which interferes with the heating structure 40).
[0173] [00173] The control unit 100 is connected to the heating structure 40 and configured to control the heating of the heating structure 40 in such a way that the heating surface 41 is brought at least to a first temperature (selected based on the materials used) for film sheet 18 and tray 7 to be suitable for sealing at least the peripheral portion of the cut film sheet in relation to the rim of the tray).
[0174] [00174] It is noted, according to a variant, that the second heating medium can also be integrated in the film retaining plate 36 which can be configured to heat the active surface 37 in such a way as to bring it to the second temperature . The heating medium can be connected with the control unit 100 and the control unit can be configured to control the heating medium in such a way that the active surface 37 of the film retaining plate 36 is brought at least to said second temperature. Depending on the circumstances, the first and second temperatures can be the same or different.
[0175] [00175] Advantageously, the control unit 100 is configured to independently control the (first and second, if present) heating medium and heating structure 40 and to independently adjust the first and second temperatures. In this way, the control unit 100 can allow an operator to adequately adjust the temperature of the heated parts of the upper tool 21 (active surface 37 and heating surface 41). The control of these temperatures by the control unit 100 allows to improve the connection between the film sheet 18 and the support or tray 7. In particular, the control unit 100 can be configured to control the first and second temperatures, as follows:
[0176] [00176] - in the case of shrink films 10 that are used, then the control unit can only cause the heating surface 41 to heat up, optionally only when the latter is pressed against the edge 4c of tray 4,
[0177] [00177] - in the case of non-heat-shrink films 10 that are used, then, the control unit can cause the entire film sheet to heat up with the first and second temperatures being, for example, equal,
[0178] [00178] - in the case of packaging with film (see, for example, Figures 12 to 17), the control unit can cause the entire film sheet to heat up, for example, with the second temperature being higher than than the first temperature.
[0179] [00179] It is noted that, in the case of film packaging, in some instances, the temperature of the gas flow ejected from the ejectors 36c (and / or the temperature of the component that defines the ejectors 36c, for example, the retaining plate 36 ) can be kept at a low temperature of about 50 ° C to 60 ° C such that the unwanted shrinkage of the film material can be partially or substantially recovered over a period after packaging (for example, typically within 24 hours after packing).
[0180] [00180] From a construction point of view, the heating structure 40 may include a metallic body that incorporates at least one resistive and / or inductive element connected to a power supply; in this case, the control unit 100 is configured to control the power supply to continuously supply current to the resistive or inductive element in such a way as to maintain the temperature of the heating surface 41 within a pre-fixed range around said first temperature.
[0181] [00181] Alternatively or in addition to this, the heating structure 40 may include at least one metallic wire directly guided by the heating surface 41 of the heating structure 40, the metallic wire being connected to a power supply and to the control unit 100 which is configured to control the power supply to supply current to the metal wire during discrete time intervals. In practice, the thermal inertia of the wire is so small that the control unit can be programmed to cause the power supply to supply current for short periods of time, for example, when the sealing of the film sheet 18 in the holder needs to happen . During the rest of the cycle described above, the power supply does not supply current to the wire, which is basically at room temperature. This is useful when it comes to shrink films.
[0182] [00182] Alternatively or in addition to this, the heating structure 40 may include a printed circuit formed on said heating surface 41 of the heating structure 40, the printed circuit being connected to a power supply and to the control unit 100 which is configured to control the power supply to supply current to the printed circuit for short periods of time, for example, when the sealing of the film sheet 18 in the holder needs to happen. During the rest of the cycle described above, the power supply does not supply current to the wire, which is basically at room temperature. This is useful when it comes to shrink films.
[0183] [00183] As for the heating medium, which can be associated with the retaining plate 36, also the heating medium can include at least one resistive and / or inductive element embedded in the body of the retaining plate and connected to a power supply. In this case, the control unit 100 is configured to control the power supply to supply current to the resistive or inductive element in such a way as to maintain the temperature of the active surface 37 of the retaining plate 36 within a pre-fixed range around of said second temperature.
[0184] [00184] Additionally or independently of this, the retaining plate can include at least one metallic wire directly guided by the active surface 37 of the retaining plate 36 and connected to a power supply and to the control unit 100 that is configured to control the supply of energy to supply current to the metallic wire during discrete time intervals. In practice, the thermal inertia of the wire is so small that the control unit can be programmed to cause the power supply to supply current for a short time. During the rest of the cycle described above, the power supply does not supply current to the wire, which is basically at room temperature.
[0185] [00185] Alternatively or in addition to this, the heating medium may include a printed circuit formed on said active surface 37 of the retaining plate 36 and connected to a power supply and to the control unit 100, which is configured to control the supply of energy to the printed circuit for short periods of time. During the rest of the cycle described above, the power supply does not supply current to the printed circuit, which is basically at room temperature.
[0186] [00186] It is noted that, when the film is heat shrinkable, the use of the heating medium can serve to increase the tension in the central portion of the film 18, after having fixed the perimeter of the film on the edge 4c.
[0187] [00187] As an additional variant, an ultrasound generator can be used in place of or in addition to the heating structure and / or heating medium. The ultrasound generator - if present - is configured to conduct pressure energy (in the form of high frequency acoustic waves) in correspondence with the area occupied by the peripheral surface 18b of the film sheet 18 and the edge 4c of the support 4. The control unit can be programmed to control the ultrasound generator to cause the emission of acoustic waves at least when the film sheet and tray 4 are brought into contact with each other, as shown in Figure 7.
[0188] [00188] As another variant, a magnetic wave generator can be used in place of or in addition to the heating structure and / or heating medium. The electromagnetic generator - if present - is configured to focus electromagnetic energy (in the form of high frequency electromagnetic waves) in correspondence with the area occupied by the peripheral surface 18b of the film sheet 18 and the edge 4c of the support 4. The control can be programmed to control the generator to cause the emission of electromagnetic waves at least when the film sheet and tray 4 are brought into contact with each other, as shown in Figure 10.
[0189] [00189] Figure 6A shows a detailed view of the heating structure 40 and the retaining plate 36, as well as of the film 18. Figure 6A is discussed in view of the comparative Figure 6B, which shows a prior art arrangement of corresponding components that do not employ ejectors 36c, as described above.
[0190] [00190] The prior art arrangement shown in Figure 6B has a heating structure 40 'with a heating surface 41', a retaining plate 36 'with an active surface 37' and suction holes 48 'in it, largely corresponding the respective elements 40, 41, 36, 37 and 48 according to the embodiments described herein. For comparison, the cut film shown in Figure 6B is indicated by the reference numeral 18 ', comprising a central portion 18a' and a peripheral portion 18b '.
[0191] [00191] The effect of supplying a controlled air or gas flow 31b to the ejectors 36c is now described with respect to both Figure 6A and Figure 6B. With the activation of suction (for example, evacuation, vacuum, etc.) through suction holes 48 'and with the deactivation of suction through channels of the backing plate (both not shown in Figures 6A and 6B), the cut film sheet 18 'remains substantially in contact with the active surface 37' of the retention plate 36 ', in a similar manner as described here with respect to the retention plate 36 and the cut film 18. With the retraction of the backing plate, chamber 24 is closed and packaging of the cut film sheet 18 'would be started with a corresponding tray or support (not shown).
[0192] [00192] However, a common problem that occurs with the cut film sheet 18 ', in particular, when using a film 10 having a thickness of 33 microns or less, is that, with the retraction of the backing plate , the peripheral portion 18b 'of the cut film sheet 18' can be curved or folded from a position suitable for packaging (corresponding to the dashed line 18d 'of Figure 6B, which substantially extends within the main plane of the cut film sheet 18 ') to a position highly unsuitable for packaging, shown in Figure 6B as the peripheral portion hanging 18b' from the cut film sheet 18 '. It is noted that the peripheral portion 18b 'can assume numerous (intermediate) positions that do not extend substantially within the main plane of the cut film sheet 18', most of which has a detrimental effect on the packaging and on the sealing of the tray or support. For example, at least part of the peripheral portion 18b 'is at risk of tipping down to a point (for example, as shown in Figure 6B), which, upon the assumption that the heating surface 41' of the heating structure 40 'is in contact with the peripheral portion 18b' of the cut film sheet 18 'positioned above the tray or support, the cut film sheet 18' cannot be sealed on the tray or support, as further described below, because the said part of the peripheral portion 18b 'which is in the downward position cannot be actuated on the heating surface 41', since it comes in direct contact with the tray or support, without any part of the peripheral portion 18b 'positioned between they. Consequently, the packaging cannot be sealed and the defective packaging must be discarded. While Figures 6A and 6B, together with the description above, focus on the situation in which the peripheral portion of the cut film sheet disadvantageously moves downward, away from the heating surface, similar problems may occur when said peripheral portion moves. move up and / or onto the heating surface. These situations may incur similar problems, when a seal cannot be reliably created, as described above, and / or when the peripheral portion of the cut film sheet is damaged or deformed due to premature contact with the heating surface or mechanical action of the heating structure and / or the retaining plate 36. The present apparatus and method are designed to address any type of folding, bending or poor positioning of the peripheral portion of a cut film sheet.
[0193] [00193] Another common problem that occurs with the cut film sheet 18 ', in particular, when using a film 10 having a thickness of 33 microns or less, is that, with the retraction of the backing plate, the The temperature of the peripheral portion 18b 'of the cut film sheet 18' may rise undesirably above a threshold where initial shrinkage and / or folding may occur. In particular, if the temperature of the film rises above a level that initiates heat shrinkage of the peripheral portion 18b 'of the film, the resulting deformation (including folding, bending, shrinking, etc.) may make it impossible to obtain a seal the packaging.
[0194] [00194] It is noted that the downward turning of the peripheral portion 18b 'of the cut film sheet 18' may occur under several different circumstances, for example, when the film 10 has a thickness of 33 microns or less and, therefore, would be more prone to deformation due to the lower inherent stiffness of the very thin film. However, the downward turn can also be caused or additionally aggravated by other factors. For example, the heat emitted from the heating surface 41 'can soften the peripheral portion 18b' of the cut film sheet 18 ', because of the initial proximity of the peripheral portion to the heating surface, which can be in the range of 3 mm to 6 mm. mm, in some preferred embodiments, in the range of 4 mm to 5 mm, which is subsequently decreased further. Another example includes deformation of the peripheral portion 18b 'of the cut film sheet 18' during injection of the controlled atmosphere or evacuation of the camera 24. In both cases, turbulence of air or gas can act on the peripheral portion 18b ', from such that the corresponding air or gas flow 30a, as shown in Figure 6B, can cause movement and / or upward / downward movement of at least part of the peripheral portion 18b '.
[0195] [00195] In order to address the problems described above, in particular, preventing any deformation (including folding, bending, shrinking, etc.) of the peripheral portion of a film, the supply of air or gas to the ejectors 36c is controlled by the control unit 100 to selectively provide an air or gas stream 31b to be ejected from the ejectors 36c in the manner described above. In particular, the flow of gas ejected through the ejectors can serve to cool the peripheral portion or portions of a film in order to prevent it from shrinking. Figure 6A shows an arrangement of components according to the first embodiment of the present invention. As shown in Figures 2 to 11, the upper tool 21 has a heating structure 40 with a heating surface 41, a retaining plate 36 with an active surface 37, and suction holes 48 as well as ejectors 36c provided therein. Except for effectors 36c, these elements largely correspond to the respective elements 40 ', 41', 36 ', 37'and 48', as shown in Figure 6B. For comparison, the cut film sheet shown in Figure 6A is indicated by reference numeral 18, comprising a central portion 18a and a peripheral portion 18b. In addition, a poorly positioned peripheral portion 18c is shown schematically as a dashed line, for comparison purposes only.
[0196] [00196] A flow of air or gas 31b ejected from the ejectors 36c runs along the upper surface of the peripheral portion 18b of the cut film sheet 18 and thus creates a pressure differential on the upper side thereof such that the peripheral portion 18b is maintained in substantially the same plane as the central portion 18a of the cut film sheet 18. Due to the flow of air or gas 31b (e.g., pressure and / or velocity of the fluid flow) ejected from the ejectors 36c along the upper surface of the peripheral portion 18b, peripheral portion 18b cannot be deformed (i.e., curved or turned) too much in the direction of air or gas flow 31b. In the event of such a deformation, the flow of air or gas 31b would exert a positive pressure on it, thus forcing the peripheral portion back (for example, downwards) to the desired position parallel to the flow of air or gas. Likewise, the film cannot be deformed (i.e., curved or turned) too far from the air or gas stream 31b. In the event of such a deformation, the flow of air or gas 31b would create a negative pressure on the upper surface of the peripheral portion 18b, thus also forcing the peripheral portion back (for example, upwards) to the desired position parallel to the air flow. or gas 31b. As described, the peripheral portion 18b is prevented from being overturned or otherwise moved downwards. The peripheral portion is additionally prevented from being turned upwards towards the heating surface 41, such that, due to the combination of the air or gas flow pressure 31b and the pressure differential created by the air or gas flow flow 41 along the peripheral portion 18b with respect to the lower side thereof, the position of the peripheral portion 18b is substantially maintained in the plane of the central portion 18a of the cut film sheet 18. The ejection of air or gas can be maintained as long as necessary, for example, until the closing of the chamber 24 and / or until the sealing of the cut film sheet 18 with the tray or the support 4 is performed. The ejection of air or gas can alternatively be intermittent, for example, allowing evacuation of the chamber 24, in which case the ejection of air or gas can be reduced or prevented until the desired level of vacuum within the chamber is reached.
[0197] [00197] Since the ejectors 36c can be arranged around the peripheral portion 18b of the entire cut film sheet 18, as required (depending, for example, on the size, shape, thickness or materials used for the film) , the entire peripheral portion 18b of the cut film sheet 18 can be maintained substantially in the plane of the central portion 18a of the film, 18, essentially corresponding to that of the active surface 37. In this way, the poor positioning of the peripheral portion 18b is substantially reduced, if not entirely prevented.
[0198] [00198] Additionally, the flow of air or gas 31b ejected from ejectors 36c can serve to regulate a desired temperature of the peripheral portion 18b of the cut film sheet 18. Due to the proximity to the heating surface 41, the temperature of the peripheral portion 18b can increase to an inappropriate temperature, for example, a temperature that affects the material properties of the cut film sheet 18. An inadequately high temperature of film 18 can result, for example, in less stiffness and / or greater softness, a shrinkage, a change in adhesive properties, deformation (for example, corrugations or curlings), compromised structural integrity, or combinations thereof. In order to reduce or prevent such harmful effects, the flow of air or gas 31b ejected from the ejectors 36c can be configured to maintain a desired temperature of the peripheral portion 18b of the cut film sheet 18.
[0199] [00199] Additionally or alternatively, the air or gas supplied by the film positioning arrangement 30a can be additionally configured to also supply the same gas or mixture of gases as the controlled atmosphere arrangement 30. In such an embodiment, the creation of an atmosphere controlled inside the chamber 24, as described above, can be assisted by the gas flow 31b supplied through the ejectors 36c. This can result in a more effective creation of the controlled atmosphere within the chamber 24, for example, due to the time that is reduced to create the desired controlled atmosphere and / or due to a more uniform distribution of the gas or mixture of gases used to create the controlled atmosphere.
[0200] [00200] In view of the structural description above of the first embodiment of the apparatus 1 below, the operation of the first embodiment is described. The operation takes place under the control of the control unit 100 and reaches a product packaging process in a tray. In this case, the described process allows packaging under a modified atmosphere. In any case, the apparatus 1 can also carry out the film packaging of the product. In addition, apparatus 1 can be used to apply a cover to the tray and, therefore, to pack in a normal ambient atmosphere.
[0201] [00201] The trays are progressively moved to the packaging assembly 8 by the transport assembly 3. At the same time, the clamping rolls allow the unwinding of the film from the roll 10 and the cutting assembly prepares the cut film sheets in number and size corresponding, preferably, exactly to the trays to be closed. In practice, the film sheets can be cut to a size that mimics that of the outer edge of the edge 4c, or they can be cut to a size radially smaller than the outer edge of the edge 4c, but sufficient to tightly close the mouth. from tray 4 and sealingly engage flange 4c with the upper surface. In some instances, the cut film sheets may be somewhat larger than required to cover the entire edge 4c, thus allowing some surplus material to extend beyond the edge 4c. In some instances, this can reduce requirements regarding the accuracy of placing cut film sheets in trays 4.
[0202] [00202] In the apparatus 1 of Figures 2-11, the packaging assembly includes, as described above, a main actuator 33. In the embodiment shown, the main actuator is guided by the frame 2 and acts on the lower tool 22 under the control of the control unit 100 for raising and lowering the lower tool 22 along the main direction A5, which is typically vertical.
[0203] [00203] Figure 2 shows a prepared cut film sheet 18 positioned on the backing plate 16 of the transfer device 7. In the present embodiment, the backing plate 16 has a vacuum retaining means in the form of channels 16a, as described above, which actively retains the cut film sheet 18 during transfer towards and towards the camera 24. It is understood that the backing plate 16 could comprise an alternative retaining means than those illustrated in Figures 2-11.
[0204] [00204] In Figure 3, the backing plate 16 was moved by the transfer device 7 to the space between the upper tool 21 and the lower tool 22 (that is, to the chamber 24), in particular, directly below the transfer plate. retention 36 and directly above and in superposition with the tray or support 4. In this embodiment, the tray or support 4 that leads to the product to be packaged is already present inside the chamber 24. However, it is understood that the movement of the tray or from the support 4 and that of the cut film sheet 18 to the chamber 24 can be executed sequentially in any order or, preferably, at the same time. At this stage, the vacuum retention medium 16a is still being supplied with a vacuum, thereby retaining the cut film sheet 18 in place.
[0205] [00205] In Figure 4, the backing plate 16 is raised towards the retention plate 36 in such a way that the cut film sheet 18 is substantially in the vicinity of the active surface 37 of the retention plate 36 or in contact with it . As shown in Figure 3, the backing plate 16 still holds the cut film sheet 18 in place.
[0206] [00206] In Figure 5, the film positioning arrangement 30a has been activated and the flow of air or gas 31b is ejected by the ejectors 36c, as described above, in order to maintain the peripheral portion 18b of the cut film sheet 18 in the present position, that is, substantially in the plane of the central portion 18a and / or in the plane of the active surface of the support plane 16. Subsequently, the vacuum retaining means 16a of the support plate 16 is deactivated.
[0207] [00207] Then, as shown in Figure 6, the retaining means 48 of the retaining plate 36 is activated and, subsequently, the backing plate 16 is moved away from the retaining plate 36. Due to the switching in the retention, the sheet of cut film 18 is now retained by the retention plate 36 and the backing plate 16 can be entirely retracted by the transfer device 7 from the space between the upper tool 21 and the lower tool 22.
[0208] [00208] After the transfer device 7 has moved the cut film sheet 18 into the packaging chamber 24 and the retaining plate 36 has received the cut film sheet (see Figures 2 to 6), the control unit 100 controls the main actuator 33 to close the packaging chamber 24 (see Figure 7) with the lifting of the lower tool 22 in such a way that the inner wall 33 intercepts the support 4 which is raised and separated from the inner element 50.
[0209] [00209] A retaining gasket (not shown) is configured to engage and retain the four corners of the cut film sheet 18 in the packaging assembly configuration 8 shown in Figure 7. In this way, the deformation and or mispositioning of the film sheet cut film 18 in the region of the corners of the same are reduced or entirely prevented. The retaining gasket is positioned so as to prevent any interference with the trays. This can be achieved, for example, by ensuring that the retaining gasket has a greater extension than the tray.
[0210] [00210] It is also noted, during the phases shown in Figures 2 to 6, that the back portion 36b interferes with an integral part with the heating structure so that the elastic pressure exerted by the element 60 can cause only a relative stroke limited descent of the retaining plate with respect to the heating surface. At this point, the packaging chamber is hermetically closed and the film sheet is retained by the retention plate 36 at some distance from the mouth of the tray or holder 4. As shown in Figure 7, the vacuum arrangement is activated and a certain amount is created vacuum degree.
[0211] [00211] As described above, the flow of air or gas 31b can be reduced or temporarily eliminated during the creation of the vacuum and evacuation of the chamber 24. Preferably, the supply of air or gas is reduced to a point that allows the efficient creation of the desired degree of vacuum.
[0212] [00212] Then, immediately after or with a certain time overlap during the creation of a vacuum, the controlled atmosphere arrangement is activated (see Figure 8) and a controlled atmosphere created inside the packaging chamber. As described above, ejectors 36c can additionally or alternatively be used in creating the controlled atmosphere. In certain variants, only the vacuum arrangement or only the controlled atmosphere arrangement can be activated. It is noted that, if it is desired to operate the apparatus 1 to simply apply a cover to the tray 4, then the vacuum arrangement and the modified atmosphere arrangement cannot be activated in any way.
[0213] [00213] An additional vertical movement imposed on the lower tool 22 by the main actuator 33 overcomes the reaction of the elastic elements 55 (see Figure 9) and brings the film sheet retained by the retaining plate to the contact with the edge 4c of the support 4 In this position, the upper tool 21 interacts with the stop portion 36b. In the example in Figures 2-11, a protrusion 21a attached to the upper tool touches the stop portion 36b so that the additional vertical movement of the lower tool would cause the vertical movement of the upper tool, the stop portion 36b and, therefore, the plate retention 36.
[0214] [00214] The control unit 10 is then configured to operate the main actuator 33 to additionally lift the lower tool 22, overcoming the reaction of the elastic element 60 and, therefore, causing the retaining plate 36 to be raised and the active surface 37 and the heating surface 41 are aligned with each other (Figure 10). In a coordinated manner, the flow of air or gas 31b ejected by the ejectors 36c is eliminated so as to correspond to the relative movement of the retaining plate 36 and the heating structure 40. Preferably, the flow of air or gas 31b is maintained, provided that the heating structure 40 does not obstruct the ejectors 36c. It is noted that the flow of air or gas 31b can be eliminated immediately at a certain point in time. Preferably, the flow of air or gas 31b can be reduced gradually over a certain amount of time (for example, in the range of a few seconds), such that the position of the peripheral portion 18b of the cut film sheet 18 is maintained in the desired manner , as described above.
[0215] [00215] In some cases, it may be desirable to keep the flow of air or gas 31b active as much as possible in order to maintain the temperature of the film, as described above. In some embodiments, the heating structure 40 can function as a part of a master valve which, in combination with the retaining plate 36 and the relative movement between the two components, can substantially block the flow of air or gas 31b from all ejectors 36c at substantially the same time and / or at the last possible moment before contact is made between the heating surface 41 and the rim 4c of the support 4, the peripheral portion 18b of the cut film sheet 18 being positioned between them. In a preferred embodiment, there is a small gap between the heating structure 40 and the retaining plate 36. In some examples, the gap is between 0.1 mm and 5 mm in size, preferably between 0.5 mm and 3 mm mm.
[0216] [00216] At this point, when the heating surface 41 of the heating structure 40 comes into contact with the peripheral portion 18b of the film sheet 18 positioned above a support 4, the control unit 100 will cause heating of the heating structure 40 such that the heating surface 41 at least partially melts the plastic material of the peripheral portion of the film sheet 18 and / or the rim 4c, thereby sealing the cut film sheet in the tray. Then, the control unit 100 then lowers the lower tool 22, and therefore opens the packaging chamber 24 to allow the tray to proceed downstream of the packaging assembly (see Figure 11). The cycle can then be repeated. In an alternative to controlled heating of the heating surface 41, the temperature of the heating surface can be kept constant, such that the seal with the contact of the heating surface 41 and the film sheet 18 is obtained. Second embodiment of the device 1
[0217] [00217] In Figures 12-16, a second embodiment of apparatus 1 is shown. For the sake of brevity, only the aspects and components of this second embodiment that differ from those of the first embodiment will be described. The remaining aspects and components are substantially the same as in the first embodiment and have been identified with the same reference numerals. The differences with respect to the first embodiment refer to the packaging assembly. In the case of Figures 12-16, the upper tool 21 has at least one retaining plate 36 having a respective active surface 37. The retaining plate 36 is terminally guided by the axis 36a and covers the entire radial extension of the end surface 23a and therefore, also of the rim 4c. The axis of the retaining plate is coupled to the upper tool 21 to allow at least movement along the direction of the double arrow A5, as described below. The holding means 38 can comprise a vacuum source 39, for example, in the form of a pump, controlled by the control unit 100 and connected to a plurality of suction holes 48 present in correspondence with the active surface 37. It is noted that , in addition to or alternatively to the vacuum source 39, the retaining means 38 may include one or more of the following:
[0218] [00218] - mechanical supports, such as tweezers, clamps or the like,
[0219] [00219] - adhesive systems, for example, comprising adhesive portions associated with the active surface 37,
[0220] [00220] - heating systems, for example, comprising heatable portions associated with the retaining plate to cause heating of the active surface 37 and, therefore, of the film sheet 18 in order to increase the adhesiveness of the film sheet to the active surface 37 ,
[0221] [00221] - electrostatic systems, for example, the active surface 37 can be charged with a different polarity than that which is typical of the plastic sheet 18.
[0222] [00222] Control unit 100 can be configured to activate medium 28, for example, vacuum source 39, and to make film retainer plate 36 receive and retain said film or sheets 18 in correspondence with the active surface 37. In particular, the control unit 100 can be configured to coordinate the activation of the medium 28, for example, of the vacuum source 39, with proper positioning of the cut film sheet 18 by the backing plate 16. For example, the control unit 100 can activate medium 28, for example, the vacuum source 39, and cause the film retaining plate 36 to receive and retain said film or sheets 18 in correspondence with the surface active 37, when the support structure 16 leading to the cut film 18 is properly positioned inside the packaging chamber below the retention plate 36. The heating means can be integrated into the film retention plate 36 which can be configured to heat the surface ie active 37. No heating structure 40 analogous to that of the first embodiment is present in the second embodiment. In some examples, the heating structure 40 may coincide with the active surface 37 (for example, when the heating surface 41 and the active surface 37 have substantially the same plane). The heating medium can be connected with the control unit 100 and the control unit can be configured to control the heating medium in such a way that the active surface 37 of the film retaining plate 36 is brought to the desired temperature . The heating means can be of the type described for the first embodiment.
[0223] [00223] The control unit can control the heating medium to generate a first temperature in the peripheral portion of surface 37 and a second temperature in the central portion of surface 37. In particular, control unit 100 can be configured to control the first and the second temperature, as follows:
[0224] [00224] - in the case of heat-shrink films 10 that are used, then, the control unit can only cause the peripheral portion of the active surface 37 to heat up, optionally only when it is pressed against the edge 4c of tray 4,
[0225] [00225] - in the case of non-heat-shrink films 10 that are used, then, the control unit can cause the heating of the entire surface 37 and, therefore, of the entire film sheet with the first and second temperatures being, for example, example, equals,
[0226] [00226] - in the case of packaging with film, then, the control unit can cause the heating of the entire active surface 37 and, therefore, of the entire film sheet, for example, with the second temperature being higher than the first temperature.
[0227] [00227] The retaining plate 36 of the second embodiment of the apparatus 1 comprises ejectors 36c similar to those described above with respect to the first embodiment. However, while in the first embodiment the ejectors 36c can be arranged around the perimeter of the retaining plate 36, in the second embodiment, the ejectors 36c are arranged exclusively in the corners of the retaining plate 36c.
[0228] [00228] Figures 17 and 18 illustrate an exemplary configuration of ejectors around the retaining plate 36 in line with the second embodiment of the apparatus 1. Figure 17 shows a top view of a tray 4 showing a sheet of film cut 18 positioned at the top and substantially in superposition with it. As can be seen in Figure 17, tray 4 is substantially rectangular in shape with rounded corner regions. The cut film sheet 18 has a correspondingly substantially rectangular shape and comprises corner portions 18e that extend beyond the rounded corner regions of tray 4. Film holding plate 36 is not shown in Figure 17, as it would also be substantially overlapping with tray 4 and cut film sheet 18.
[0229] [00229] Figure 18 shows a cross-sectional view of the arrangement shown in Figure 17, taken along line XVIII. Figure 18 also shows the cross section of the film holding plate 36 with tray 4 positioned below, substantially in contact with the active surface 37 of the film holding plate 36 and with the cut film 18 positioned between tray 4 and the active surface 37. In this embodiment, only the corner portions 18e of the cut film sheet 18 extend beyond the corner regions of tray 4 so that most of the peripheral portions of the cut film sheet 18, that is, of the portions peripherals that extend parallel and along the edges of tray 4, do not extend beyond the edge 4c of tray 4 and therefore cannot be folded or curved downwards, as described above with respect to the first embodiment. However, corner portions 18e of the cut film sheet 18 extend beyond the corner regions of tray 4, and are therefore subjected to the above-described problem of film material that is folded or curved (for example, downward) out of position substantially parallel to a plane defined by most of the cut film sheet 18, which is substantially parallel to the active surface 37 of the film retaining plate 36.
[0230] [00230] In order to prevent folding or bending of the corner portions 18e of the cut film sheet 18, the ejectors 36c are arranged in the corner regions and configured to eject a flow of air or gas 31b in a similar manner to the ejectors 36c , as described above with respect to the first embodiment. In the second embodiment, however, the ejection of air or gas flows 31b is only necessary in the corner portions 18e of the cut film sheet 18 where folding or bending out of position is possible, as described above. Other characteristics, functions and / or details (for example, the supply of air or gas to the ejectors, lines or pipes leading to them, the positioning of the film, etc.) largely correspond to those already described in detail with respect to to the first embodiment.
[0231] [00231] The operation of the second embodiment takes place under the control of the control unit 100 and reaches a process of packaging a product in a tray. In this case, the described process allows the product to be packaged with film. In any case, the apparatus 1 is also capable of packaging under a modified atmosphere.
[0232] [00232] In the apparatus 1 of Figures 12-16, after the transfer device has moved the cut film sheet 18 into the packaging chamber 24 and the retaining plate 36 has received the cut film sheet (see Figure 12) , the control unit 100 controls the film positioning arrangement 30a to supply the air or gas flow 31b to the ejectors 36c (in a manner substantially corresponding to that described above with respect to the first embodiment). The air or gas flow creates an air or gas flow in the corner regions of the film retaining plate 36 and therefore prevents the corner portions 18e from bending or bending (not shown in Figures 12-16; see, instead, for example, Figures 20 and 21) of the cut film sheet 18 while the backing plate 16 is retracted from the chamber 24. The air or gas flow 31b is supplied in substantially the same manner, as described above with respect to to the first embodiment. For example, the flow of air or gas 31b is supplied and maintained in the same manner as described above and can be started, stopped, increased or decreased in the same way. In particular, the flow of air or gas 31b can be supplied in a manner adapted to the evacuation of the chamber 24 and flow 31b can comprise air or gas (for example, the same controlled gas flow, as supplied by the controlled atmosphere arrangement) .
[0233] [00233] The control unit 100 controls the main actuator 33 to close the packaging chamber 24 (Figure 13) with the lifting of the lower tool 22 in such a way that the inner wall 33 intercepts the support 4 while the flow of air or gas 31b is supplied for ejectors 36c. At this point, the packaging chamber is hermetically closed and the film sheet 18 is held by the retaining plate 36 at some distance from the mouth of the tray or holder 4. As shown in Figure 13, the vacuum arrangement can be activated , thus creating a certain degree of vacuum. An additional vertical movement imposed on the lower tool 22 by the main actuator 33 overcomes the reaction of the elastic elements 55 (see Figure 14) and brings the film sheet retained by the retaining plate in contact with the edge 4c of the support 4. Substantially the same time (for example, at the same time or well before or just after), the supply of air or gas flow 31b to the ejectors 36c is diminished or interrupted as the corner portions 18e of the cut film sheet 18 are positioned , as desired. In this configuration, the corner portions 18e of the cut film sheet 18 are prevented from having a detrimental effect on the placement of the cut film sheet 18 or on its subsequent attachment (for example, by heat treatment) to it in tray 4.
[0234] [00234] The heating medium causes the heating of the film sheet 18 positioned above a support 4. Since the material of the cut film sheet 18 is suitable for vacuum packaging, the heating surface is heated to a temperature that allows subsequent desired deformation of the central portion 18a of the cut film sheet 18, which typically expands or stretches and thus adapts to the contours of the product inside the tray 4. Then, the control unit causes the pump 39 to pump gas to chamber 24 (for example, instead of operating as a vacuum source), thus causing the film sheet to drape downward over the product. Alternatively, the control unit can simply connect the suction holes 48 to the environment (e.g., surrounding atmosphere), as it is typically sufficient to establish normal pressure within the chamber 24. Since the cut film sheet 18 is in watertight contact with the rim 4c of tray 4 or tray 4 itself and has been substantially adapted to the contours of the product present in tray 4, the remaining space between the cut film sheet 18 and the product and / or tray 4 still corresponds to the vacuum established before . With the establishment of normal pressure in chamber 24, the cut film sheet 18 is tightly pressed against the contours of the product and tray 4, such that a minimum amount of controlled air or gas remains inside the package.
[0235] [00235] The additional heating generated by the heat medium can facilitate the sealing of the peripheral portion of the film sheet to the edge 4c (see Figure 15). The control unit 100 operates the main actuator to lower the lower tool 22, and therefore the packaging chamber 24 can be opened to allow the tray to proceed downstream of the packaging assembly. The cycle can then be repeated.
[0236] [00236] It is noted that the cut film sheet 18 can be either adhered to the tray 4 and the edge 4c thereof by the heat treatment described above and / or by the heat sealing of the peripheral portion of the cut film sheet 18 along the edge 4c of tray 4, as also described above. Device control unit 1
[0237] [00237] The device according to the invention has at least one control unit. The control unit 100 (schematically shown in Figure 1) can comprise a digital processor (CPU) with memory (or memories), an analog type circuit, or a combination of one or more digital processing units with one or more processing circuits analog. In the present description and the claims, it is indicated that the control unit 100 is "configured" or "programmed" to perform certain steps. This can be achieved, in practice, by any means that allows the configuration or programming of the control unit. For example, in the case of a control unit 100 comprising one or more CPUs, one or more programs are stored in an appropriate memory. The program or programs containing instructions that, when executed by the control unit, cause the control unit 100 to perform the steps described and / or claimed in connection with the control unit. Alternatively, if the control unit 100 is of an analog type, then the control unit circuits will be designed to include circuits configured, in use, to process electrical signals, in such a way as to perform the control unit steps described here. .
[0238] [00238] In general terms, the control unit 100 acts on the transport assembly 3, the film cut assembly 6, the transfer device 7, the packaging assembly 8 and particularly the upper and / or lower tools 21, 22, the vacuum arrangement 27, the controlled atmosphere 30, and controls the same. In particular, the control unit 100 can be configured to control the execution of the following cycle:
[0239] [00239] command the transport assembly 3 to move said support along the predefined path and to the packaging chamber 24 so that each support 4 to be packed is housed in the respective seat 23b;
[0240] [00240] control the film cutting assembly 6 to cut at least one sheet of film 18 exactly dimensioned to cover the upper opening of the support 4 bounded by the edge 4c and at least part of the upper surface of the edge or the entire upper surface of the edge ,
[0241] [00241] command the transfer device 7 to position the cut film sheet 18 inside the packaging chamber 24 and above the respective support 4,
[0242] [00242] command the upper tool 21 to retain the cut film sheet 18 above and at a distance from said support 4,
[0243] [00243] commanding the film positioning arrangement to position the peripheral portion 18b, if the cut film sheet 18 is substantially within the plane of the cut film sheet 18,
[0244] [00244] command the packaging assembly 8 to move from the first to the second operating condition in order to tightly close the packaging chamber 24,
[0245] [00245] to control the vacuum arrangement 27 to remove air from the said hermetically sealed packaging chamber,
[0246] [00246] to control the controlled atmosphere arrangement 30 to inject a gas or a mixture of gases into the packaging chamber,
[0247] [00247] command the packaging assembly 8 to tightly fix the film sheet 18 on said support 4,
[0248] [00248] command the packaging assembly 8 from the second to the first operating condition,
[0249] [00249] command the transport assembly 3 to move the support 4 with the film sheet tightly fixed 18 outside the packaging chamber 24, then repeating the above cycle.
[0250] [00250] The control unit can also be configured to control the apparatus 1 in order to perform any of the packaging processes described below or claimed in the attached claims. Packing processes
[0251] [00251] Packing processes according to the aspects of the invention will now be described.
[0252] [00252] The following processes can be performed by the apparatus according to any of the above embodiments and variants under the supervision of the control unit 100. According to one aspect of the invention, it is the control unit 100 that is controlled and programmed to execute the processes described below using an apparatus 1, as described in one of the above embodiments or as claimed in any of the appended claims.
[0253] [00253] The trays (or supports) 4 are progressively moved to the packaging assembly 8, for example, by the transport assembly 3. At the same time, the film 10a is unwound from the roll 10 and the cutting assembly 6 that acts outside of the packaging chamber 8 prepares the cut film sheets 18 in number and size corresponding to the trays to be closed. In practice, the film sheets can be cut into a shape and size that largely corresponds to those on the outer edge of the edge 4c (for example, substantially identical in size or slightly larger than those on the outer edge of the edge 4c, and covering the opening of tray 4) or they can be cut to a size radially smaller than the outer edge of the flange 4c, but large enough to tightly close the opening of the tray 4 and to effectively engage the upper surface of the flange 4c. In other words, the radial width of the cut film sheets can be comprised between the maximum radial width and the minimum radial width of the edge 4c of the tray or support 4. In some examples, the cut film sheets may be somewhat larger than what is necessary to cover the entire edge 4c, thus allowing certain surplus material to extend beyond the edge 4c.
[0254] [00254] The preparation of the tray can be done beforehand or the trays can be formed in line in a forming station substantially in a similar way to the cutting of the sheets of film that is performed. The cutting of film 10a on film sheets 18 takes place at a remote station from the location where the film sheets are attached to the tray. The cut film sheet or - if a plurality of trays are treated at the same time - a plurality of cut film sheets are moved to the packaging assembly 8. The packaging assembly 8 is left open for a period of sufficiently long time for numerous trays 4 and for a corresponding number of film sheets 18 to be properly positioned within the packaging chamber 24 defined the packaging assembly. The transfer device 7 can be used, as described above, to move the film sheets, which have been cut out of the packaging assembly 8, in the direction and into the packaging chamber 24. Then, the packaging assembly 8 is closed and the film sheets are retained above the respective tray at a sufficient distance to allow gas to circulate within the tray. The packaging chamber is hermetically closed in the sense that only controlled flows of gas can be removed and / or injected into chamber 24 under the control of apparatus 1 (for example, controlled by control unit 100 thereof). At this point, the packaging process may vary depending on the type of packaging and depending on the type of film sheet available.
[0255] [00255] With the positioning of the cut film sheet 18 (or of multiple cut film sheets), the control unit 100 controls the film positioning arrangement 30a to supply an air or gas flow 31b to the ejectors 36c, preventing thus folding or curving part of the peripheral portion 18b or the entire peripheral portion 18b or the corner portions 18e of the cut film sheet 18 out of position. As a result, also portions of the cut film sheet 18 (e.g., peripheral portions 18b or corner portions 18e) are held in substantially the same plane as the rest of the cut film sheet 18. The supply of air or gas flow 31b is maintained, as desired, and can be maintained until the packaging of tray 4 has essentially been carried out (for example, when the cut film sheet 18 is sealingly attached to tray 4 or when the cut film sheet 18 is substantially in contact with contact with tray 4 and / or the product contained therein).
[0256] [00256] The supply of air flow or gas 31b can be controlled depending on the evacuation and / or the supply of a controlled gas flow, as described above. For example, the gas supplied to the ejectors 36c can substantially correspond to the gas that forms the controlled flow of gas supplied by the controlled atmosphere arrangement. In addition, the supply of air or gas flow 31b can be started, stopped, increased or decreased, as desired in combination with one or more of the steps described above.
[0257] [00257] If, for example, a sheet of non-shrinkable film is being used as the cover for the tray, and if it is intended to create packaging in a modified atmosphere, then a partial vacuum will be created inside the packaging chamber and a gas for contemporary modified atmosphere or subsequently injected. When a partial vacuum is formed in the packaging chamber 24 (for example, by the control unit 100 that controls the vacuum pump 28 to withdraw gas from said packaging chamber 24), the gas will be removed until a pressure between 100 and 300 mbar, optionally between 150 and 250 mbar, is reached inside the packaging chamber 24. This pressure level is low enough, but not too low, so that the film sheet from the retaining plate 36 is prevented. This can be achieved, for example, by ensuring that the pressure level formed in correspondence with the suction holes 48 is below the pressure level established in the packaging chamber. At this stage, the film sheet (or film sheets) is held in place by the retaining plate, which can be provided with a means for retaining the film in a suitable position, as described above. In particular, the peripheral portion 18b and / or the corner portions 18e are held in position, as described above. Then, after a pre-set delay from the start of the gas withdrawal (for example, after a pre-set delay from the activation of said vacuum pump 28) or after a pre-set vacuum level has been reached inside said packaging chamber 24, a modified atmosphere gas is injected into the packaging chamber 8. The injection of said controlled gas flow to create a modified atmosphere can be initiated even while the gas withdrawal is still happening in such a way to shorten the time to create the modified atmosphere. The risks involved with high oxygen content are the same as discussed above. Alternatively or in addition to the injection of the controlled gas flow, substantially the same controlled gas can be supplied by the film positioning arrangement 30a for the ejectors 36c, as described above, for example, to fill the chamber 24 more quickly, more evenly or more efficiently. Furthermore, since it is preferable to prevent a very strong vacuum in the packaging chamber, while it is desirable to ensure a suitable atmosphere within the chamber, it is advantageous to interrupt the generation of vacuum after the gas injection has already started. In this way, the pressure inside the chamber never goes below a desired value. During the overlap, the injected gas is mixed with residual air and, continuing to draw vacuum, the modified atmosphere-air-gas mixture continues to be removed so that the initial air quantity is, in any case, decreased. Again, suitable pumps must be used (for example, pumps suitable for pumping gas with a high oxygen content).
[0258] [00258] The film sheet 18 can be uniformly heated or can be heated at least in correspondence with the peripheral portion 18b. This operation can take place using the heating structure 40 and / or the heating medium associated with the retaining plate 36. At least the peripheral portion 18b of the cut film sheet 18 or the edge 4c is brought to a temperature that allows the thermal connection from the peripheral portion 18 to the rim 4c of tray 4 and a watertight closure of tray 4. Thereafter, or at the same time as heating, the film sheet 18 is lowered and tightly adhered to the tray. If ultrasonic or microwave based heaters are used, they will be operated at this stage and also the edge 4c of tray 4 can be heated at the same time. Once the connection has been completed, the packaging chamber can be opened and the tray 4 provided with a watertight cover formed by the cut film sheet 18 can proceed outside the packaging chamber 24. If, for example, a film sheet heat shrink is being used as a cover for the tray, and if it is intended to create a modified atmosphere packaging, then a partial vacuum will be created inside the packaging chamber and a contemporary modified atmosphere gas or subsequently injected. When a partial vacuum is formed in the packaging chamber 24 (for example, by the control unit 100 that controls the vacuum pump 28 to withdraw gas from said packaging chamber 24), the gas will be removed until a pressure between 100 and 300 mbar, optionally between 150 and 250 mbar, is reached inside the packaging chamber 24. This pressure level is low enough, but not too low, so that the film sheet from the retaining plate 36 is prevented. This can be achieved, for example, by ensuring that the pressure level formed in correspondence with the suction holes 48 is below the pressure level established in the packaging chamber. At this stage, the film sheet is held by the retention plate, which can be provided with a means for retaining the film in a suitable position, as described above. Heat shrink films can be very thin (for example, the thickness can fall to a range of 1540 microns, in some applications, up to a range of 10-15 microns) and handling after curing is difficult so it is relevant that the levels pressure in the packaging chamber and on the retaining plate are adequately controlled. After a pre-set delay from the start of the gas withdrawal (for example, after a pre-set delay from the activation of said vacuum pump 28) or after a pre-set vacuum level has been reached inside said packaging chamber 24, a modified atmosphere gas is injected into the packaging chamber 24. The injection of said controlled gas flow to create the modified atmosphere can be initiated even while the gas withdrawal is still taking place in order to shorten the time to create the modified atmosphere. Alternatively or in addition to the injection of the controlled gas flow, substantially the same controlled gas can be supplied by the film positioning arrangement 30a for the ejectors 36c, as described above, for example, to fill the chamber 24 more quickly, more evenly or more efficiently. Furthermore, since it is preferable to prevent a very strong vacuum in the packaging chamber and at the same time it is desirable to ensure a suitable atmosphere within the chamber, it is advantageous to interrupt the generation of vacuum after the gas injection has already started. In this way, the pressure inside the chamber never falls below a desired value. During the overlap, the injected gas is mixed with residual air and, continuing to draw vacuum, the modified atmosphere-air-gas mixture continues to be removed so that the initial air quantity is, in any case, decreased. This gas discharge and the mixture of the gas and residual air are very important in order to achieve the desired controlled atmosphere in an effective and efficient manner, while ensuring that the desired pressure (ie, the vacuum level) is achieved.
[0259] [00259] The film sheet 18 can be heated in correspondence with its periphery 18b. This operation can happen with the use of the heating structure 40. At least the peripheral portion 18b of the cut film sheet 18 or of the edge 4c is brought to a temperature that allows the thermal connection of the peripheral portion 18b to the edge 4 of tray 4 and a watertight closure of tray 4. Then, the film sheet is lowered and tightly adhered to tray 4. In the event that ultrasonic or microwave-based heaters are used, they are operated at this stage, and the edge 4c of the tray may also be used. be simultaneously heated. Once the connection has been completed, the packaging chamber can be opened and the tray 4 provided with a watertight cover formed by the cut film sheet 18 can proceed outside the packaging chamber 24.
[0260] [00260] If, for example, a non-shrinkable film sheet is being used and is intended to create a packaging with vacuum film, then a vacuum will be created inside the packaging chamber. Then, the film sheet 18 may be uniformly heated or may be heated at least in correspondence with its periphery 18b at a first temperature suitable for heat sealing and may be heated in correspondence with its central portion 18a at a second temperature, for example , equal to or above the first temperature, suitable for making the film sheet deformable. This operation can take place using the heating structure 40 and / or the heating medium associated with the retaining plate 36. Then, once the vacuum level suitable for packaging with film has been reached, the film sheet is lowered in such a way. so that the peripheral portion 18b of the film sheet 18 contacts the edge 4c of tray 4. If ultrasonic or microwave-based heaters are used, they will be operated at this stage, and the edge 4c of the tray may also be used. 4 be heated at the same time. In general, the heating of the film 18 or of the peripheral portion 18b of the same occurs preferably at the same time as the film is moved to (that is to say, approached to) the tray 4 or the rim 4c of the same and comes in contact with the themselves. The retaining plate 36 releases the film sheet and normal atmospheric pressure is created above the cut film sheet 18 which is draped downwardly and matches the shape of the product P and the inner walls of the tray creating a plastic film film around of the product and on the surfaces of tray 4 that are not occupied by product P. In other words, when a predefined low pressure is reached inside the packaging chamber 24 and therefore inside the tray or support 4 below the film sheet 18, the film sheet 18 will be released and will be directed downwards by the vacuum inside the support 4. Once the film sheet 4 is heated (and softened) under the effect of the vacuum inside the support 4, it deforms in a way to adhere to product P and the internal surface of support 4 (see Figures 15 and 16). In practice, the film is at least adhered to the rim 4c and the portions of the inner surface of the support 4. Once the connection has been completed, the packaging chamber can be opened and the tray 4 provided with a tightly associated film formed by the cut film sheet 18 can move out of the packaging chamber 24.
[0261] [00261] It is noted that an ejection of a flow of gas or air 31b can be controlled so as not to interfere with the creation and / or maintenance of the vacuum inside the chamber 24. For example, the amount of gas or air ejected can be minimized in order to obtain, depending on the material and properties of the film used, the effect of positioning the peripheral portion 18 and / or the corner portion 18e of the cut film sheet 18, while substantially (or at least very slowly) ) does not change the pressure and / or the composition of the atmosphere inside the chamber 24.
[0262] [00262] Alternatively, the creation of a vacuum inside the chamber 24 can be skipped and the cut film sheet 18 can be adhered to tray 4 creating a sealed tray within the ambient atmosphere inside the package.
[0263] [00263] While the invention has been described in connection with what is currently considered to be the most practical and preferred embodiments, it is understood that the invention is not limited to the described embodiments, but, on the contrary, is intended to cover various modifications and provisions equivalents included in the spirit and scope of the appended claims. For example, the elastic elements 55, 60 and 80 can be replaced by linear actuators controlled by the control unit 100.
[0264] [00264] The specific nature of the described actuators is exemplary and alternative types of actuators can be used, since the type of movement imposed on the moving parts in which said actuators are operating is substantially the same.
[0265] [00265] It is also noted that, although the embodiments described show a single packaging assembly 8, multiple packaging assemblies can be used in parallel together with multiple transfer devices 7 (as shown, for example, in Figures 1 and 2, or any alternative to them) in order to optimize productivity.

权利要求:
Claims (20)
[0001]
Apparatus (1) for packaging a product (P) disposed on a support (4), said support (4) having a base wall (4a) and a side wall (4b), said device (1) characterized by the fact that you understand: a packaging assembly (8) configured to securely attach one or more sheets of film (18) to one or more of the supports (4), the packaging assembly (8) including: - a lower tool (22) comprising at least one inner wall (23) defining a pre-fixed number of seats (23b) for receiving one or more supports (4), and - an upper tool (21) facing the lower tool (22) and comprising a film retaining plate (36) configured to retain one or more sheets of film (18), the film retaining plate (36) having a respective active surface (37) configured to receive one or more sheets of film (18), at least the upper and lower tools (21; 22) cooperating to define a packaging chamber (24); said packaging assembly (8) being configured to operate at least in a first operating condition, where said packaging chamber (24) is opened to receive one or more sheets of film (18), and in a second packaging condition operation, wherein said packaging chamber (24) is closed, optionally hermetically closed; a film supply assembly (5) configured to supply a continuous film (10a); a film cutting assembly (6) active on the continuous film (10a) and configured to cut film sheets (18) of pre-fixed length from said continuous film (10a); and a control unit (100) connected to the packaging assembly (8) and configured to command the packaging assembly (8) to go from the first to the second operating condition and vice versa, where the film retaining plate (36) has a lateral surface that extends substantially transverse, optionally substantially perpendicular, to a plane defined by the active surface (37), the film retaining plate (36) comprising a plurality of ejectors (36c ) arranged on the side surface, each ejector of the plurality of ejectors (36c) being configured to eject a gas flow (31b) in a direction substantially parallel to said plane and substantially distant from a center of the active surface (37).
[0002]
Apparatus according to claim 1, characterized in that the film cutting assembly (6) is located outside said packaging chamber (24).
[0003]
Apparatus according to claim 1 or 2, characterized in that it additionally comprises at least one of: - a vacuum arrangement (27) connected to the packaging chamber (24) and configured to remove gas from said packaging chamber (24), the vacuum arrangement (27) optionally comprising at least one vacuum pump (28) and at least at least one evacuation tube (29) that connects the inside of said packaging chamber (24) to the vacuum pump (28), said control unit (100) being additionally configured to control the vacuum arrangement (27) to remove gas from said packaging chamber (24) at least when the packaging assembly (8) is in said second operating condition with said packing chamber (24) hermetically closed; and - a controlled atmosphere arrangement (30) connected to the packaging chamber (24) and configured to inject a controlled gas flow into said packaging chamber (24), the controlled atmosphere arrangement (30) optionally comprising at least one device injection (31) and at least one injection tube (32) that connects the inside of said packaging chamber (24) to the injection device (31), said control unit (100) being further configured to control said controlled atmosphere arrangement (30) to inject said controlled gas flow at least when the packaging assembly (8) is in said second operating condition with said packing chamber (24) hermetically closed; where the controlled atmosphere arrangement (30) is configured to inject gas into the packaging chamber including an amount of one or more of N2, O2 and CO2 that is different from the amount of these same gases, as present in the atmosphere at 20 ° C and at sea level (1 atmospheric pressure); optionally where - the apparatus including both the vacuum arrangement (27) and the controlled atmosphere arrangement (30) and where the control unit (100) is configured to control said controlled atmosphere arrangement (30) to initiate the injection of said flow controlled gas, either after a pre-set delay from activating said vacuum arrangement (27), or after a pre-set vacuum level has been reached within said packaging chamber (24), optionally where said control unit (100) is configured to control said controlled atmosphere arrangement (30) to initiate the injection of said controlled gas flow while said gas withdrawal from said packaging chamber is still in progress; and / or - where the control unit is configured to operate the vacuum arrangement (27) to remove gas from said packaging chamber (24) and create a vacuum level in the packaging chamber (24) with a pressure between 10 and 30 kPa (100 and 300 mbar), optionally between 15 and 25 kPa (150 and 250 mbar).
[0004]
Apparatus, according to any of the preceding claims, characterized by the fact that: - the film retaining plate (36) comprises a means for retaining (38) one or more sheets of film (18) in correspondence with said active surface (37), said retention means (38) comprising one or more in the group of: - a vacuum source (39) controlled by the control unit (100), the control unit (100) being configured to activate the vacuum source (39) and cause the film holding plate (36) to receive and retain one or more sheets of film (18) in correspondence with the active surface (37), - mechanical supports associated with the active surface (37), - adhesive portions associated with the active surface (37), - heatable portions associated with the retaining plate (36) and controlled by the control unit (100) to cause the active surface (37) and, therefore, the film sheet (18) to heat up in order to increase the adhesiveness of the foil active surface film (37), - electrical systems associated with the retaining plate (36) and controlled by the control unit (100) to charge the active surface (37) with a predetermined polarity; optionally where - the packaging assembly (8) additionally comprises: - a main actuator (33) active in at least one of said upper and lower tools (21; 22), the main actuator (33) being controlled by the control unit (100), - the control unit (100) being configured to act on the main actuator (33) and cause the relative movement of the upper and lower tools (21; 22), along a main direction (A5), between said first condition of operation, where the upper tool (21) is spaced from the lower tool (22) and said packaging chamber (24) is opened to receive one or more of said film sheets (18), and said second operating condition , where a sealing surface (34) of the upper tool (21) seals against a closing surface (35) of the lower tool (22) to tightly close said packaging chamber (24) with respect to an atmosphere inside the device (1).
[0005]
Apparatus according to claim 4, characterized by the fact that it comprises a heating structure (40) peripherally associated with the film retaining plate (36) and having a respective heating surface (41) that extends radially out with respect to to the active surface (37) of the retaining plate (36), where: - at least when the packaging assembly (8) is in said second operating condition, the heating surface (41) of the heating structure (40) will face an end surface (23a) of said inner wall (23) which delimits a respective seat from said seats (23b) in the lower tool (22) and - the heating structure (40) and the film retaining plate (36) are relatively mobile with each other along said main direction (A5) such that the heating surface (41) of the heating structure (40) can be selectively positioned in a position where it does not come into contact with the film sheet and in a position where it comes in contact with the film sheet (18) positioned above a support (4) located in one of said seats ( 23b), and - the control unit (100) is configured to control the heating of the heating structure (40) in such a way that the heating surface (41) is brought at least to a first temperature.
[0006]
Apparatus according to any one of the preceding claims, characterized by the fact that it comprises a heating means integrated in the film retaining plate (36) and controlled by the control unit (100), the control unit (100) being configured to control the heating medium in such a way that the active surface of the film retaining plate (36) is brought at least to a second temperature between 150 ° C and 260 ° C, optionally between 180-240 ° C, more optionally between 200-220 ° C
[0007]
Apparatus according to claim 4, characterized by the fact that it comprises a heating means integrated in the film retaining plate (36) and controlled by the control unit (100), the control unit (100) being configured to control the heating means such that the active surface of the film retaining plate (36) is brought at least to a second temperature between 150 ° C and 260 ° C, optionally between 180-240 ° C, more optionally between 200- 220 ° C, and where the control unit (100) is configured to independently control the heating medium and the heating structure (40) and to independently adjust the first and second temperatures.
[0008]
Apparatus according to any one of claims 4 to 7, characterized in that the heating structure (40) comprises one of the following: - a metallic body that incorporates at least one resistive and / or inductive element connected to a power supply and the control unit (100) which is configured to control the power supply to supply current to the resistive or inductive element in such a way maintaining the temperature of the heating surface (41) within a pre-fixed band around said first temperature; - a metallic wire directly guided by the heating surface (41) of the heating structure (40), the metallic wire being connected to a power supply and the control unit (100) which is configured to control the power supply to supply current to the metal wire for discrete time intervals followed by time intervals where no current supply to the metal wire occurs, in particular, where the control unit (100) is configured to control the power supply to supply current to the metallic thread, when sealing the film sheet (18) to the support (4); and - a printed circuit formed on said heating surface (41) of the heating structure (40), the printed circuit being connected to a power supply and to the control unit (100) which is configured to control the power supply to supply current to the printed circuit during discrete time intervals followed by time intervals where no current supply to the printed circuit takes place, in particular, where the control unit (100) is configured to control the power supply to supply current for the printed circuit, where the film sheet (18) is sealed to the support (4).
[0009]
Apparatus according to any one of claims 4 to 8, characterized in that the film retaining plate (36) is rigidly coupled to the upper tool (21) and mounted on it in such a way that: - the film retaining plate (36) is not relatively movable with respect to the upper tool (21) at least along said main direction (A5), - the active surface (37) is flush with the lower surface of the lower tool (21), and where said active surface of the retaining plate is sufficiently dimensioned to overlap, optionally completely overlap, with an end surface (23a) of said inner wall (23) that delimits a respective seat of said seats (23b ) on the bottom tool (22).
[0010]
Apparatus according to any one of the preceding claims, characterized in that the film retaining plate (36) has a substantially rectangular shape comprising four optionally rounded corners, and in which the apparatus includes one or more of the following characteristics: - the plurality of ejectors (36c) comprises at least one ejector (36c) arranged in each of the four corners of the retaining plate (36); - the plurality of ejectors (36c) is arranged around a perimeter of the film retaining plate (36) defined by the side surface, optionally where the plurality of ejectors is spaced in a position substantially equidistant from each other; - the plurality of ejectors (36c) is in fluid communication with a common pipe (36d) configured to supply the gas flow (31b) for each ejector of the plurality of ejectors (36c); - the plurality of ejectors (36c) is angularly arranged with respect to the center of the active surface (37) at substantially the same angular distance from each other; - a film positioning arrangement (30a) connected to the plurality of ejectors (36c) and configured to supply the gas flow (31b) to the plurality of ejectors (36c), optionally the film positioning arrangement (30a) comprising at least at least one supply device (31a) and at least one supply tube (32) that connects the supply device (31a) with the plurality of ejectors (36c), and wherein the control unit (100) is further configured to control said film positioning arrangement (30a) to supply said gas flow (31b) comprising one or more of the following: - start supplying the gas flow (31b); - increase the supply of the gas flow (31b); - decrease the supply of gas flow (31b); and - interrupt the supply of the gas flow (31b).
[0011]
Apparatus according to claim 3, characterized in that it additionally comprises a film positioning arrangement (30a) connected to the plurality of ejectors (36c) and configured to supply the gas flow (31b) to the plurality of ejectors (36c) ), optionally the film positioning arrangement (30a) comprising at least one supply device (31a) and at least one supply tube (32) that connects the supply device (31a) with the plurality of ejectors (36c); it's from the gas flow (31b) has the same composition as the controlled gas flow injected by the controlled atmosphere arrangement (30), optionally where the film positioning arrangement (30a) comprises a supply switch configured to controllably select a first source gas supply and a second gas supply source for the gas flow (31b), the first gas supply source being configured to supply gas having the same composition as the controlled gas flow injected by the controlled atmosphere arrangement ( 30), the second gas supply source being configured to supply air; optionally where the control unit (100) is additionally configured to control said film positioning arrangement (30a) to supply said gas flow (31b) comprising one or more of initiating the supply of the gas flow (31b), increase the supply of the gas flow (31b), decrease the supply of the gas flow (31b), and interrupt the supply of the gas flow (31b).
[0012]
Apparatus according to claim 10 or 11, characterized in that the control unit (100) is configured to perform the following steps: - controlling said film positioning arrangement (30a) to start supplying the gas flow (31b) to the ejectors (36c), - controlling said vacuum arrangement (27) to remove gas from said packaging chamber (24), - controlling said controlled atmosphere arrangement (30) to start the injection of the controlled gas flow, - controlling said controlled atmosphere arrangement (30) to interrupt the injection of the controlled gas flow, - controlling said film positioning arrangement (30a) to interrupt the supply of gas flow (31b) to the ejectors (36c); optionally where the step of controlling said vacuum arrangement (27) to withdraw gas from said packaging chamber (24) further comprises controlling the film positioning arrangement (30a) to decrease or interrupt the supply of the gas flow (31b) to the ejectors (36c) during gas withdrawal from the packaging chamber (24), optionally additionally comprises control of the film positioning arrangement (30a) to restart or increase the gas flow supply (31b) to the ejectors (36c) while the gas withdrawal from the packaging chamber (24) is still in progress.
[0013]
Apparatus according to claim 12, characterized in that the step of controlling the controlled atmosphere arrangement (30) to initiate the injection of the controlled gas flow additionally comprises the control of the film positioning arrangement (30a) to initiate the supply of a gas to the ejectors (36c) having the same composition as the controlled gas flow.
[0014]
Apparatus according to any one of the preceding claims, characterized in that the packaging assembly (8) additionally comprises at least one side wall (42) movably associated with one of the upper tool (21) or the lower tool ( 22), where: - the side wall (42) has a front surface (43a) configured to rest against a support surface (43b) of the other between said upper tool (21) or lower tool (22), - the side wall (42) is mounted on the packaging assembly in such a way that when the packaging assembly moves from said first to said second operating condition, the side wall (42) correspondingly moves from a first position , where the front surface of the side wall (43a) is spaced from said support surface (43b) so that the wrapping chamber (24) is left open to receive one or more of said sheets of film (18), to a second position, where the front surface of the side wall (43a) seals against said support surface (43b) in such a way that said packaging chamber (24) is hermetically closed with respect to an outside atmosphere of the appliance (1).
[0015]
Apparatus according to any one of the preceding claims, characterized in that the lower tool (22) is provided with multiple seats (23b), each to host a corresponding support (4), and the upper tool (21) is provided with a corresponding plurality of retaining plates (36), each for retaining a respective sheet of film (18).
[0016]
Apparatus, according to any of the preceding claims, characterized by the fact that - the apparatus comprises a frame (2) which leads to: - the transport assembly (3), - the packaging assembly (8), - the film supply assembly (5), which comprises a roll of film supported by a roll holder driven by said frame, - the film cutting assembly (6), which comprises at least one blade (14) guided by said frame (2) and active in a position located between said packaging assembly (8) and said film supply assembly (5), where the control unit (100) is configured to execute the following cycle: - controlling the transport assembly (3) to move said support (4) from said packaging chamber (24); - control the film cutting assembly (6) to cut at least one sheet of film (18), - control the transfer device (7) or the upper tool (21) to position the cut film sheet (18) inside the packaging chamber (24) and above the respective support (4), - control the upper tool (21) to retain the cut film sheet (18) above said support (4) and at a distance from it, - command the packaging assembly (8) to pass from the first to the second operating condition, optionally commanding the vacuum arrangement (27) to remove air from the said hermetically sealed packaging chamber (24), and / or command the controlled atmosphere arrangement (30) for injecting a gas or mixture of gases into the packaging chamber (24), - control the packaging assembly (8) to tightly fix the film sheet (18) to said support (4).
[0017]
Process of packaging a product (P) arranged on a support (4), said support (4) having a base wall (4a) and a side wall (4b), said process optionally using an apparatus (1), as defined in any of the preceding claims, characterized by the fact that it comprises the following steps: - unwinding a film (10a) from the roll (10), - crosswise cut the unwound portion of the film (10a) and prepare a cut film sheet (18), - moving the cut film sheet (18) into a packaging chamber (24) of a packaging assembly (8) and in the vicinity of a film holder (36) disposed within the packaging chamber (24), the holder film (36) showing an active surface (37), - activating the ejection of a plurality of gas streams (31b) around a perimeter of the film holder (36), the plurality of gas streams (31b) being ejected over a peripheral portion (18b, 18c) of the foil cut film (18), preferably in a direction substantially parallel to a plane defined by the cut film sheet (18) and away from a center of the cut film sheet, in order to position and / or maintain the peripheral portion (18b, 18c ) substantially within the plane of the cut film sheet (18), - moving a support (4) into the packaging chamber (24) and below the film support (36) substantially in superposition with the cut film sheet (18), - move the support (4) to a position substantially in contact with the cut film sheet (18) - disable the ejection of the plurality of gas flows (31b), - heat seal the film sheet (18) on the support (4).
[0018]
Process according to claim 17, characterized by the fact that it additionally comprises: - after the step of moving the support (4) to the packaging chamber (24), tightly close the packaging chamber (24) with the cut film sheet (18) retained above the support (4), optionally the sheets of cut film (18) being retained at a sufficient distance to allow gas to circulate within the support (4), and - after the heat sealing step of the film sheet (18) in the support (4), open the tightly closed packaging chamber (24) and move the support (4) with the cut film sheet (18) sealingly attached to the even outside the packaging chamber (24).
[0019]
Process according to claim 17 or 18, characterized in that the cutting of the film (10a) in the film sheets (18) takes place outside the packaging chamber (24) at a remote station from the location where the film sheets are attached to the supports, and the support (4) comprises a horizontal edge (4c) that emerges radially from said side wall (4b), optionally where the film sheet (18) is cut to a size identical to that of the outer edge of the edge (4c) or in a size radially smaller than the outer edge of the lip (4c), but sufficient to seal the mouth of the tray (4) and seal the lip (4c) on the upper surface.
[0020]
Process according to any one of claims 17 to 19, characterized in that it additionally comprises: - evacuating the hermetically sealed packaging chamber (24), and / or injecting a controlled gas flow, the controlled gas flow being configured to create a modified atmosphere within the chamber; or to additionally understand: - evacuate the hermetically closed packing chamber (24) until a pressure between 10 and 30 kPa (100 and 300 mbar), optionally between 15 and 25 kPa (150 and 250 mbar), is reached inside said packing chamber packaging (24) and then - while the film sheet (18) is kept at a distance from the mouth of a support - inject a controlled gas flow into the packaging chamber (24), the controlled gas flow being configured to create a modified atmosphere, optionally where the injection of said controlled gas flow to create a modified atmosphere is performed while the evacuation step is still in progress; and - uniformly heat the film sheet (18) if the film sheet is not heat shrinkable, or - heating a peripheral portion (18b) of the film sheet (18) if the film is heat shrinkable; and - bringing the film sheet (18) close to the support (4) and sealingly attaching it to the support edge (4c), preferably the step of heating the film sheet (18) or the step of heating the peripheral portion ( 18b) of the film sheet being carried out substantially at the same time as the step of bringing the film sheet (18) closer to the support (4); and / or additionally understand: - heating a peripheral portion (18b) of the film sheet (18) to a first temperature suitable for heat sealing, and heating a central portion (18a) to a second temperature suitable to make the film sheet deformable, optionally the second temperature being equal to or greater than the first temperature.

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同族专利:

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公开号 | 公开日

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ES2609057T3|2017-04-18|

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WO2015121266A1|2015-08-20|

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EP2905233A1|2015-08-12|

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AU2015217755B2|2018-12-20|

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EP2905233B1|2016-09-28|

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CA2939352A1|2015-08-20|

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AU2015217755A1|2016-09-01|

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BR112016018223A2|2020-12-08|

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NZ723166A|2021-05-28|

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US10737811B2|2020-08-11|

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法律状态:
2020-03-31| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2020-12-22| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-02-17| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 10/02/2015, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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EP14154691.1A|EP2905233B1|2014-02-11|2014-02-11|Apparatus and process for packaging a product|

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EP14154691.1|2014-02-11|

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