• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    An arrangement (30) for removing a fiber track from a ñber transport support (21) comprises a doctor blade (34) and a doctor blade (32) having a bank contacting edge (33). The doctor blade (32) and the doctor beam (34) are attached to each other by a rotatable attachment (37). The arrangement further comprises a hose (40) for fluids arranged to apply a force between the doctor beam (34) and the doctor blade (32) at a distance from the rotatable the attachment (37) when pressurized to fl surface the bank contacting edge (33) against the fi conveyor support (21) and a hose pressurizing arrangement connected to the hose (40). The arrangement can be used in a double wire press. A method of operating such an arrangement preferably comprises pressurizing the hose and controlling the pressurization depending on an operating condition. (Fig. 3)
    公开号:SE0950242A1
    申请号:SE0950242
    申请日:2009-04-14
    公开日:2010-10-15
    发明作者:Leif Oedmark
    申请人:Metso Paper Inc；
    IPC主号:
    专利说明:

    10 15 20 25 30 is also quite demanding. The temperature is often in the range of 70-90 ° C and can vary over time and the environment typically contains peroxides. To reduce abrasion of the wire and at the same time withstand the demanding conditions, the doctor blade is typically made of a polymeric material, typically a high molecular weight polyethylene material. Furthermore, at these temperatures, both plastic deformation of the material is not uncommon as displacements caused by varying temperatures in different parts of the press.
    A general problem in the prior art is that doctor blade arrangements cause too much abrasion on the wire and / or cannot compensate for worn wires, doctor blade deformation or varying ambient temperatures.
    SUMMARY An object of the present invention is therefore to provide a doctor blade arrangement which exhibits low abrasion on the wire, well-adapted elastic behavior and suitable scraping properties.
    The above objects are achieved by arrangement according to the appended claims. In general terms, in a first aspect, an arrangement for removing a fiber track from an ñber transport support comprises a doctor blade and a doctor blade having a bank contacting edge.
    The fiber web has a basis weight of over 1000 g / m2. The doctor blade and the doctor beam are attached to each other by a rotatable attachment. The arrangement further comprises a hose for ider uider arranged to apply a force between the doctor blade and the doctor blade at a distance from the rotatable attachment when it is pressurized to fl surface the bank contacting edge against the carrier support.
    In a second aspect, a double wire press for dewatering an overspension comprises lower rollers, an endless lower wire, upper rollers and an endless upper wire, and an arrangement according to the first aspect arranged for removing a fi berban from at least one of the endless upper wire and the endless lower wire.
    In a third aspect, a method of operating an arrangement for removing an ñber web from a ert bert transport support comprises pressurizing a hose for ider uider arranged to apply a force between a doctor blade and a doctor blade at a distance from a rotatable attachment between the doctor beam and the doctor blade to move a bank-contacting end of the doctor blade towards the transport support. The method further comprises controlling the pressurization depending on an operating condition of a device providing the fibrous web.
    An advantage of the present invention is that the wear on the doctor blades and the transport supports is significantly reduced.
    BRIEF DESCRIPTION OF THE DRAWINGS The invention, together with further objects and advantages thereof, is best understood by reference to the following description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a schematic illustration of a double wire press; FIG. 2 is a schematic illustration of an embodiment of a doctor blade arrangement according to the present invention; FIG. 3 is a schematic illustration of the embodiment of Fig. 2 with pressurized hose; FIG. 4 is a block diagram of an embodiment of a dual wire press arrangement according to the present invention; FIG. 5 is a flow chart of steps in an embodiment of a method according to the present invention; and FIG. 6 is a schematic illustration of another embodiment of a doctor blade arrangement according to the present invention. 10 15 20 25 30 DETAILED DESCRIPTION Throughout the drawings, the same reference numerals are used for similar or corresponding elements.
    Fig. 1 schematically illustrates a double wire press 1. The illustration is very simplified to facilitate the understanding of the general principle.
    The double wire press 1 comprises an endless upper wire 6A running along a path around upper rollers 8A. The double wire press 1 also includes an endless lower wire 6B running along a path around lower rollers 8B. A bers suspension is introduced into the space between the endless upper wire 6A and the endless lower wire 6B through a front box 10 at an inlet 2 of the double wire press 1. The flow path of the bersus suspension / web is indicated by arrows 5. The fiber suspension is thus provided into a space 14 between it. the endless upper wire 6A and the endless lower wire 6B. The two wires 6A, 6B cooperate with each other through a drainage section 20 of the road 5, in which the wires 6A, 6B form a wedge-shaped drainage space for the bers suspension between each other. Thus, during the movement of the wires 6A, 6B through the dewatering section 20, the wires 6A, 6B successively compress the bersuspension in the wedge-shaped space, whereby the bersuspension is initially pressed and dewatered and forms a continuous iber path between the wires 6A, 6B. At an outlet 3 of the double wire press 1 the web is released from the wires 6A, 6B and collected in a shredder 12. Scraper arrangements 30 are provided at the surface of the wires 6A, 6B at a respective roller 8A, 8B.
    At the outlet of the double wire press 1, the fi berban is peeled off from the wires. In most situations, the fiber web is unifying in itself and the fiber web is typically released from the wire without problems. However, on certain occasions, e.g. when the double wire press is started or shut down or when disturbances from normal operating conditions occur, there may be parts of (or even the entire path) that continue to follow one of the wire surfaces instead of being released. If such parts of the material are allowed to follow the endless wire into the interior of the double wire press again, this can cause serious problems. A scraper arrangement 30 is typically therefore provided in connection with the outlet of the double wire press 1. As described in the background section, scraper arrangements according to the prior art have a number of disadvantages. The scraper arrangement 30 is provided at at least one of the wires 6A, 6B and typically at both.
    An embodiment of an arrangement for removing a fiber path from a wire according to the present invention is illustrated in Fig. 2, i.e. a scraper arrangement 30. A roller 8 drives a transfer conveyor 21, in this embodiment an endless wire 6, in a conveying direction 26. In other embodiments the transfer conveyor 21 could be e.g. the surface of a roller. A fiber web, in this embodiment a web of cellulosic pulp, is intended to be transported on a surface 24 of the endless wire 6 and released therefrom before the endless wire 6 returns to the interior of the double wire press. The doctor blade assembly 30 includes a doctor blade 32 attached to a doctor blade 34. The doctor blade 32 is provided to prevent any portion of the fiber web from following the fiber transport support beyond the outlet 3. The doctor blade 32 is mechanically supported by the doctor beam 34, and the doctor beam 34 attaches to the main equipment attachment , i.e. in this embodiment the double wire press. In this embodiment a part of the doctor blade is formed as a clamping plate 36, which clamps the doctor blade against the doctor beam 34 with a pivot point 35. The clamp plate 36 is firmly fixed to the main part of the doctor beam 34, in this embodiment with bolts 38. In the present embodiment the clamp plate 36 is bent in such a way that outside the pivot point 35 there is a distance 39 between the doctor blade 32 and the clamping plate 36, which allows the doctor blade to rotate out from the doctor blade surface around the pivot point 35. The clamp plate 36 and the end of the doctor blade 34 thus together form a rotatable attachment 37 of the doctor blade 32.
    The doctor blade arrangement 30 is preferably originally mounted in such a way that a bank contacting edge 33 of the doctor blade 32 is placed just at the surface of the wire 6, when the doctor blade 32 is placed along the surface of the doctor beam 34. When ambient conditions change, e.g. due to abrasion of the wire, different temperatures or plastic deformation of the doctor blade, a gap may be left between the bank contacting edge 33 and the surface of the wire 24. For such occasions a fluid hose 40 is provided in a recess 41 in the doctor blade 32. The hose 40 can generally pressurized with any fl uid - gas or liquid and is therefore adapted to be connected to a hose pressurizing arrangement. In the present embodiment, the hose 40 is intended to be pressurized by air.
    Fig. 3 illustrates a situation when the hose 40 is pressurized by a hose pressurizing arrangement (not shown). The hose 40 expands and protrudes beyond the recess 41 and exerts a force on a support surface 42 of the doctor beam 34. This support surface 42 may be part of the main doctor beam 34 itself or be part provided with a surface coating adapted for interaction with the expanded the hose 40. In general terms, the hose 40 is arranged to apply a force between the doctor blade 34 and the doctor blade 32 at a distance from the pivot point 35 when it is pressurized. The rear end of the doctor blade 32 is thereby moved out from the surface of the doctor beam 34, leaving a space 43 therebetween. This force acts to move the bank contacting edge 33 against the fiber transport means 21, in this embodiment the wire 6. The bank contacting edge 33 is thus held against the surface 24 of the wire 6 by a force determined by the pressure applied in the hose 40. The rotation of the doctor blade 32 is typically limited by the distance 39 to the clamping plate 36. The bank contacting edge 33 follows the surface 24 of the wire 6 even if the wire is unevenly worn. Also mechanical for fl surfaces in the scraper arrangement 30 as a result of e.g. temperature differences are compensated by such an arrangement. Furthermore, if the doctor blade 32 itself, which is typically made of high molecular weight polyethylene, undergoes plastic deformation, this is also compensated.
    Now we return to Fig. 2. When the rather thick fiber web comes into contact with the doctor blade 32 which is gently pressed against the wire 6, the fiber web also creates a force F on the doctor blade 32. This force F increases the pressure on the web contacting the edge 33 against the surface 24 of the wire 6. The doctor blade 32 wants to rotate around the pivot point 35. A higher normal force N is thus obtained, which increases the frictional force R from the wire 6. The higher the force F, the better and denser the doctor blade 32 is pressed against the wire 6, and the doctor blade 6 move the ban berbanan away from the wire. Due to this function, there is only a need for a small pressure in the hose 40 during normal operation to keep the doctor blade 32 close to the wire 6. Such a lower pressure gives a lower friction and longer life for the wire 6 and the doctor blade 32.
    Thus, during most of the operating time of a double wire press, the release of the fi berbanan works, i.e. in this case the release of a mat of pulp, without any need for assistance from any unloaded scraper arrangement.
    During such periods, it would therefore be advantageous if the doctor blade 32 was not actively pressed against the surface of the wire 6. As mentioned above, this could reduce the wear both on the wire 6 and on the doctor blade 32. There is then a need to be able to control the pressurization of the hose 40 in dependence on the actual operating conditions of the double wire press.
    The upper doctor blade in a double wire press is typically not in contact with the carpet of pulp when the machine is running. The doctor blade only picks up or pulls out small amounts of fibers that have become stuck in the wire. The smaller fi ber particles follow more or less the wire, even if the scraper blade has detached fi bears from the wire. Spray systems are typically provided to handle these particles later.
    The lower doctor blade is also not in contact with the carpet of pulp when the machine is running properly. The structure of the carpet of pulp and its own weight pulls the carpet of pulp out of the wire so that the doctor blade goes freely without coming into contact with the carpet of pulp.
    This typical phenomenon occurs with carpets of pulp having a sufficient strength and weight, and it is currently considered that it is a requirement to have a basis weight of more than 1000 g / m 2, and preferably more than 1200 g / m 2 , to bring about this phenomenon. In start-up processes and shut-down processes for the machine, both the upper and lower doctor blades are often in contact with the carpet of pulp. There is then a need to have a strong doctor blade, but made of a soft material to reduce the damage to the wire.
    This is due to the high contact forces that this thick carpet of mass produces. The minimum basis weight of carpet mats made from double wire presses is 1200 g / m2, which makes the present doctor blade arrangements according to the present invention particularly suitable.
    A further advantageous function of the lower doctor blade arrangement is to provide for a contact between the carpet of pulp and the chuck.
    This stabilizes the carpet of pulp on its way to the strip screw. Without this contact, the mat is broken by pulp more easily due to the action of the forces applied to the strip screw and from its own weight. When a fracture occurs, the carpet of pulp loses the force of its own weight which pulls out the carpet of pulp and there is typically a doctor blade contact against this very thick carpet of pulp which gives more fiber losses and abrasion to the doctor blade. Typically, the wire speed is in the range of 10-40 m / min during normal operation.
    A fiber handling system according to an embodiment of the present invention is illustrated in Fig. 4. A double wire press 1 for dewatering a fiber suspension has a doctor blade arrangement 30, e.g. according to the embodiment of Figures 2 and 3, mounted at the outlet of the double wire press 1. A hose pressurizing arrangement 50 is connected to a hose on the doctor blade arrangement 30. A control unit 52 is arranged to control the hose pressurizing arrangement 50. The control unit 52 is connected to receive information about the operating conditions of the double wire press 1. Based on this information, the control unit 52 can pressurize the hoses in the scraper arrangements 30 when needed, e.g. during start-up or shut-down of the double-wire press 1, or when other disturbances in operation are detected. During normal operation of the double wire press 1, the control unit 10 15 may instead allow a release of the pressure and thereby allow the doctor blade to rotate out of the wire surface.
    Fig. 5 illustrates a flow chart of steps in an embodiment of a method according to the present invention. A method of operating an arrangement for removing a fiber path from a wire begins in step 200. In step 210, a hose for pressure is pressurized. The hose is arranged to apply a force between a doctor blade and a doctor blade at a distance from a rotatable attachment between the doctor beam and the doctor blade to move a bank-contacting edge of the doctor blade towards the wire. The pressurization is controlled in step 212 depending on an operating condition of a device providing the fibrous web. The procedure is completed in step 299.
    The embodiment illustrated in Figures 2 and 3 has the hose in a recess in the doctor blade and arranged to act against the doctor beam.
    Furthermore, the hose applies the force to the doctor blade on a side opposite to the bank contacting edge relative to the rotatable attachment 37 and the pivot point 35. However, there are also alternative embodiments. An alternative embodiment is illustrated in Figs. Here, the hose 40 is provided in a recess 41 in the doctor blade instead. The hose 40 is thus arranged to act against a support surface 42 on the doctor blade 32. In another alternative embodiment, the hose 40 can be provided so that the hose applies the force to the doctor blade on the same side as the bank contacting edge relative to the rotatable attachment.
    The clamping of the doctor blade 32 against the doctor beam 34 at limited surfaces gives rise to a simple embodiment of a rotatable attachment. One skilled in the art will recognize that other types of rotatable fasteners may also be used, such as various types of hinges.
    In the above embodiments, the transport support of a wire is exemplified. However, the present ideas can also work well with other types of transport support, such as e.g. different types of rollers. The conditions at the outlet of an arrangement for handling fibrous webs, such as a double wire press, are quite special. The environment is hazardous and typically includes peroxides. At the same time, the temperatures are often in the range 70-90 ° C, but can also vary considerably, especially during start-up and shut-down of the arrangement for handling ñber tracks. The presented solutions are well adapted to cope with such environments at the same time as they provide a simple and cost-effective operation.
    The embodiments described above are to be understood as a few illustrative examples of the present invention. Those skilled in the art will appreciate that various modifications, combinations, and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different sub-solutions in the different embodiments can be combined in other arrangements, where this is technically possible. However, the scope of the invention is limited by the appended claims.
    权利要求:
    Claims (10)
    [1]
    An arrangement (30) for removing a fi berban from a fi bert transport support (21), comprising: a doctor blade (34); and a doctor blade (32) having a bank contacting edge (33); and a hose (40) for exiting arranged to apply a force between the doctor beam (34) and the doctor blade (32) when pressurized to surface the bank contacting edge (33) against the carrier support (21), characterized in that the web has a basis weight over 1000 g / m2; the doctor blade (32) and the doctor beam (34) are attached to each other by a rotatable attachment (37); which hose (40) is arranged to apply the force at a distance (d) from the rotatable attachment (37) to surface the bank contacting edge (33) by rotating the doctor blade (32) relative to the doctor beam (34).
    [2]
    The arrangement according to claim 1, characterized in that the hose (40) is provided in a recess (41) in the doctor blade (32) and is arranged to act against the doctor beam (34).
    [3]
    The arrangement according to claim 1, characterized in that the hose (40) is provided in a recess (41) in the doctor blade (34) and is arranged to act against the doctor blade (32).
    [4]
    The arrangement according to any one of claims 1 to 3, characterized in that the hose (40) applies the force to the doctor blade on a side opposite to the bank contacting edge (33) relative to the rotatable attachment (37).
    [5]
    The arrangement according to any one of claims 1 to 4, characterized in that the hose (40) is a gas hose. 10 15 20 25 30
    [6]
    The arrangement according to any one of claims 1 to 5, characterized in that the rotatable attachment (37) is provided by clamping the doctor blade between a main part of the doctor beam (34) and a clamping plate (36), in turn mechanically attached to said main body of the doctor beam (34).
    [7]
    The arrangement according to any one of claims 1 to 6, characterized by a hose pressurizing arrangement (50) connected to the hose (40).
    [8]
    The arrangement according to claim 7, characterized by a control unit (52) arranged to control the hose pressurizing arrangement (50).
    [9]
    A double wire press (1) for dewatering a ers bers suspension, comprising lower rollers (8B), an endless lower wire (ÖB), upper rollers (8A) and a breathless upper wire (6A), characterized by an arrangement (30) according to any one of claims 1 to 8 provided for removing a web from at least one of the endless upper wire (6A) and the endless lower wire (6B).
    [10]
    A method of operating an arrangement for removing a fi berban from a fi bert transport support, comprising the step of: pressurizing (210) a hose (40) for ider uider arranged to apply a force between a doctor blade (34) and a doctor blade (32). ) for moving a bank-contacting edge (33) of the doctor blade (32) against the fiber transport support (21), characterized by: rotating the doctor blade (32) relative to the doctor beam (34) by applying the force at a distance (d) from a rotatable attachment ( 37) between the doctor blade (34) and the doctor blade (32) to provide the movement of the bank contacting edge (33); and controlling (212) the pressurization depending on an operating condition of a device providing the track.
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    同族专利:
    公开号 | 公开日
    SE534503C2|2011-09-13|
    CA2756641A1|2010-10-21|
    US20120012267A1|2012-01-19|
    EP2419562A1|2012-02-22|
    EP2419562A4|2012-11-28|
    WO2010120228A1|2010-10-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
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    GB825436A|1957-02-22|1959-12-16|D S T Pattern And Engineering|Improvements in or relating to doctor knives|
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    DE3142657C2|1981-09-29|1985-06-20|Sulzer-Escher Wyss GmbH, 7980 Ravensburg|Drainage device|
    FI106730B|1999-10-29|2001-03-30|Metso Paper Inc|Arrangement at wet end of paper machine|
    DE10017038A1|2000-04-05|2001-10-11|Voith Paper Patent Gmbh|Belt cleaning scrapers of a papermaking/cardboard production machine, comprises a second scraper applied to the hand-over belt with a stronger pressure to detach a clinging web on a web break|
    DE10251983A1|2002-11-08|2004-05-19|Helmut Strauch|Doctor blade mounting, to clean roller surfaces in the papermaking and steel industries, has a mounting tube at the base plate to fit into a quadrilateral tube attached to the cover plate|
    PL204172B1|2007-05-16|2009-12-31|Sławomir Stera|Scraper handle of papermaking machine|
    法律状态:
    2013-12-03| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE0950242A|SE534503C2|2009-04-14|2009-04-14|An arrangement and method for removing a fiber web from a fiber transport support|SE0950242A| SE534503C2|2009-04-14|2009-04-14|An arrangement and method for removing a fiber web from a fiber transport support|
    PCT/SE2010/050344| WO2010120228A1|2009-04-14|2010-03-29|A doctor blade arrangement and method in fibre processing|
    CA 2756641| CA2756641A1|2009-04-14|2010-03-29|A doctor blade arrangement and method in fibre processing|
    US13/258,566| US20120012267A1|2009-04-14|2010-03-29|Doctor blade arrangement and method in fibre processing|
    EP10764734A| EP2419562A4|2009-04-14|2010-03-29|A doctor blade arrangement and method in fibre processing|
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