• 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:
    A wood material dryer (1) has a first gas permeable belt (4) on which wood material to be dried can be transported, and a second gas permeable belt (14) on which wood material to be dried can be transported. The second belt (14) is arranged below the first belt (4) and is arranged to receive material which has been transported over the first belt (4) and which falls down on the second belt (14). A first heating coil (24) is arranged above the first belt (4), and is arranged to heat air intended to dry material transported on the first belt (4). A second heating coil (26) is arranged above the second belt (14) and is arranged to heat air which is intended to dry material which is transported on the second belt (14). A duct (32, 40) is arranged to conduct drying air which has passed through the second heating coil (26) and the second belt (14) to the first heating coil (24) and further through the first belt (4). Publication image: Fig.2
    公开号:SE0900475A1
    申请号:SE0900475
    申请日:2009-04-09
    公开日:2010-10-10
    发明作者:Ola Larsson；Peter Thellsson
    申请人:Andritz Tech & Asset Man Gmbh；
    IPC主号:
    专利说明:

    15 20 25 30 2 band. A drying air is preheated in a heating coil and is then passed through the first and second belts for drying the wood chips and / or the wood fiber which is transported over the belts.
    SUMMARY OF THE INVENTION An object of the present invention is to provide a wood material dryer for drying solid materials originating in living trees, which wood material dryer is more efficient and compact than the previously known wood material dryers.
    This object is achieved with a wood material dryer, which has a first gas permeable belt on which wood material to be dried can be transported, and a second gas permeable belt on which wood material to be dried can be transported, the second belt being arranged below the first belt and being arranged to receiving material transported over the first belt and falling therefrom, which wood material dryer is characterized in that it has a first heating coil, which is arranged above the first belt and is arranged to heat air which is intended to dry wood material as transport. ported on the first belt, and a second heating battery arranged above the second belt and arranged to heat air intended to dry wood material transported on the second belt, the wood material dryer having at least one duct arranged to conduct drying air which has passed through the second heating coil and the second belt to the first coil and further through the first band.
    An advantage of this wood material dryer is that the consumption of ambient air becomes small, since the drying air used for drying on the second belt is heated, from a relatively high temperature, and is used once again for drying, this time on the first belt. This reduces the amount of ambient air that may be affected by substances in the wood material that are dried. In addition, the consumption of energy in the first heating coil decreases, since the drying air entering the first heating coil has a relatively higher temperature. The heating of the air in the first heating coil also makes the drying process more efficient, since the material falling on the second belt will be relatively dry, which means that the drying on the second belt can be carried out with a relatively shorter belt. , than would otherwise have been possible. The fact that the material leaving the first strip is relatively dry has an additional advantage in that the mixing of the material as it falls on the second strip becomes more efficient, compared to if the material had been wetter, and thus had also stuck together more. A further advantage is that when the respective heating batteries are placed above the respective belts, the dryer becomes very compact in its design.
    According to a preferred embodiment, the first belt has a first drying section which is arranged to support and transport wood material to be dried, the first heating coil extending along at least 60% of the length of the first drying section. According to another embodiment, the second belt has a second drying section which is arranged to support and transport wood material to be dried, the second heating coil extending along at least 60% of the length of the second drying section. An advantage of these embodiments is that the respective heating coil can be made narrow, since each surface portion of the heating coil only needs to heat drying air which is to dry a short surface portion of the drying portion.
    According to a preferred embodiment, the first heating coil has a width corresponding to at least 70% of the width of the first strip. According to another embodiment, the second heating coil has a width corresponding to at least 70% of the width of the second strip. An advantage of these embodiments is that the drying air can be distributed evenly over the material to be dried in a very efficient manner, without the need for any further efforts in the form of pressure drop-creating guide rails and similar gas-conducting devices.
    According to a preferred embodiment, the first and second heating batteries and the first and second bands are arranged vertically one above the other in a housing. An advantage of this embodiment is that a very compact wood material dryer is provided, which makes it easy to place in tight spaces.
    According to a preferred embodiment, a first inlet for supplying drying air to the second heating coil is arranged in a vertical side wall of said housing, the second heating coil tilting towards the first inlet and forming an angle to the horizontal plane which is 5- 30 °. According to another preferred embodiment, a second inlet for supplying drying air to the first heating coil is arranged in a vertical side wall of said housing, the first heating coil leaning towards the second inlet and forming an angle with the horizontal plane which is 5-30 °. An advantage of these embodiments is that a compact design of the wood material dryer is achieved, whereby said angles contribute to efficiently and with low pressure drop distribute the drying air evenly over the material to be dried, and that liquid formed when steam condenses in the heating coil flows out. the same.
    According to one embodiment, a heat exchanger is arranged to heat exchange at least a part of the drying air which has been used for drying on the first belt with at least a part of the air which is intended to be used for drying on the second belt. An advantage of this embodiment is that an improved energy efficiency is achieved since a part of the energy content of the consumed drying air is used in heating the air, such as ambient air, which is to be used for drying on the second belt.
    Another object of the present invention is to provide an efficient and space-saving way of drying wood material.
    This object is achieved with a method of drying wood material in a wood material dryer, in which way the wood material is first dried and transported on a first gas permeable belt and then allowed to fall on a second gas permeable belt arranged below the first belt on which the tree material is transported and further dried, the wood material dryer has a first heating coil arranged above the first belt and a second heating coil arranged above the second belt, the drying air being first passed through the second heating coil and then through the second belt during drying of wood material transported thereon, at least a portion of the drying air which has passed through the second belt is collected and passed through the first heating coil and then through the first belt while drying wood material which is transported thereon.
    An advantage of this method is that a relatively small amount of ambient air is consumed, since the drying air used in drying on the second belt is at least partially reused in the drying on the first belt. Particles and vaporized substances released during drying on the second belt, where drying takes place at a higher temperature, can also be trapped in the wood material on the first belt, where drying takes place at a lower temperature. Furthermore, the method will be energy efficient, since the drying air used for drying on the second belt will often maintain a relatively higher temperature than the ambient temperature, which reduces the energy consumption in the first heating coil.
    According to a preferred embodiment, the pressure drop in the drying air over the first heating coil is 20 - 200 Pa. According to another embodiment, the pressure drop in the drying air over the second heating coil is 20 - 200 Pa. An advantage of these embodiments is that the respective heating battery itself distributes the drying air evenly over the material to be dried, without causing a high pressure drop which lowers the energy efficiency.
    According to a preferred embodiment, the tree material falls freely and substantially vertically downwards from the first band to the second band. An advantage of this is that the wood material is mixed well, which makes the drying on the second strip more efficient.
    Further advantages and features of the invention will become apparent from the following description and the appended claims.
    Brief Description of the Drawings The invention will be described in the following by means of exemplary embodiments and with reference to the accompanying drawings.
    Fig. 1 is a cross-sectional view, showing a wood material dryer seen from the side.
    Fig. 2 is a cross-sectional view, showing the tree material dryer shown in Fig. 1 seen in the section ll-ll.
    Fig. 3 is a schematic side view, illustrating a wood material dryer which is divided into modules.
    Fig. 4 is a cross-sectional view, illustrating a wood material dryer according to an alternative embodiment.
    Description of preferred embodiments Fig. 1 schematically shows a wood material dryer 1 for drying solid material originating in living trees, such as conifers and deciduous trees. The solid material can thus be bark, sawdust, wood chips, needles, root parts, branch parts, etc.
    Typically, the solid material has been comminuted to a particle size of 5-100 mm.
    The wood material dryer 1 has a housing 2. A first endless belt 4 is arranged in the upper part of the housing 2. The first endless belt 4 is gas permeable, and can for instance be formed of composite sheet segments with punched holes, or of a steel net with a suitable mesh size. The endless belt 4 runs over a first roller 6 and a second roller 8, which are located at substantially the same horizontal level. A portion, which may be called the first drying portion 10, of the first endless belt 4, which portion 10 is for the most part located between the rollers 6, 8, is arranged to carry and transport, in the direction according to the arrow P1 shown in Fig. 1, the material M to be dried.
    The material M to be dried is introduced into the housing 2 through an inlet opening arranged in its upper portion in the form of an inlet funnel 12. The material M falls via the inlet funnel 12 onto the drying portion 10 of the belt 4 next to the first roller 6 and forms a material blanket with a thickness of typically 100-200 mm. The belt 4 is fed by a motor, not shown, around the rollers 6, 8, which causes the material M to be guided in the direction of the second roller 8, according to the arrow P1.
    As the material M passes the second roll 8, it falls on a second endless belt 14 arranged below the first endless belt 4. A horizontal wall 15 separates the first belt 4 from the second belt 14, and the material M falls on the second belt. 14 via an opening in this horizontal wall 15. The second endless belt 14 is thus arranged in the lower part of the housing 2. The second endless belt 14 is gas permeable, and may be formed, for example, of composite sheet segments with punched holes, or of steel mesh with a suitable mesh size. The second endless belt 14 runs over a first roller 16 and a second roller 18, which are located at substantially the same horizontal level. As can be seen from Fig. 1, the second endless belt 14 extends beyond the first endless belt 4 in the right-hand portion of the housing 2.
    This relationship causes the material M which has passed the second roll 8 and falls freely from the first endless belt 4 to land on a portion, which may be called a second drying portion 20, of the second endless belt 14, which portion 20 for the most part is located between the rollers 16, 18 and is arranged to support and transport, in the direction according to the arrow P2 shown in Fig. 1, the material M to be dried. When the material M falls freely from the first belt 4 and down on the second belt 14, the material M will also be mixed, which results in a more even drying.
    The material M thus falls on the drying portion 20 of the belt 14 next to the first roller 16. The belt 14 is fed by a motor, not shown, around the rollers 16, 18 which causes the material M to be guided in the direction of the second roller 18, according to the arrow P2. As the material M passes past the second roller 18, it falls into an outlet arranged below the second endless belt 14 in the form of an outlet funnel 22.
    Along the first endless belt 4, and located above the first drying section 10, extends a first heating coil 24. The heating coil 24 extends along a length LV1 which is suitably at least 60% of the length of the first drying section 10 LT1, i.e. LV1> or = LT1 * 0.60. Normally, it is inappropriate for the length LV1 to be substantially longer than LT1, i.e. the length LV1 is suitably at most 120% of the length LT1 of the first drying section 10. In this context, the length LT1 of the drying section 10 is defined as the distance from the position where the material M falls down on the belt 4, from the inlet 12, to the position where the material M falls down from the belt 4.
    Along the second endless belt 14, and located above the second drying section 20, extends a second heating coil 26. The heating coil 26 extends along a length LV2 which is suitably at least 60% of the length of the second drying section 20 LT2, i.e. LV2> or = LT2 * 0.60. Normally, it is inappropriate for the length LV2 to be substantially longer than LT2, i.e. the length LV2 is suitably at most 120% of the length LT2 of the first drying section 20. In this context, the length LT2 of the drying section 20 is defined as the distance from the position where the material M falls on the second belt 14, from the first belt 4, to the position where the material M falls down from the second belt 14.
    A first flow of drying air TL1 is led, in a manner to be described in more detail below with reference to Fig. 2, through the second heating battery 26, further through the material M transported on the drying section 20 during drying thereof, and further down through the gas permeable second endless belt 14. 10 15 20 25 30 8 A second flow of drying air TL2 is led, in a manner to be described in more detail below with reference to Fig. 2, through the first heating coil 24, further through the material M transported on the drying section 10 during drying thereof. , and further down through the gas permeable first endless belt 4.
    The fact that the heating coil 26 extends along a length LV2 which is suitably at least 60%, even more preferably at least 70%, of the length LT2 of the second drying section 20 means that the heating coil 26 can be made narrow because each surface portion of the battery 26 only needs to heat drying air In the same way, the heating coil 24 can also be made narrow thanks to the fact that it extends along a length LV1 which is suitably at least 60%, even more preferably at least 70%, of the length of the first drying portion 10. LT1. This helps to give the dryer 1 a limited height H.
    Fig. 2 shows the needle tree material dryer 1 seen in the section ll-ll shown in Fig. 1.
    The dryer 1 has a first air inlet 28 which is arranged in a first vertical side wall 30, which is parallel to the conveying direction of the belts 4, 14. The inlet 28 is arranged in a position located below the first endless belt 4 and above the second endless belt 14. Ambient air, which typically has a temperature of -10 ° C to + 25 ° C, is led through the inlet 28 into the housing 2 and through the second heating coil 26 to form the first flow of drying air TL1. As shown in Fig. 2, the second heating coil 26, which has the general shape of a straight block, is arranged vertically above the belt 14 and is angled relative to the belt 14 and the inlet 28. The heating coil 26 is thus inclined towards the inlet 28 and forms an angle A1 , which is typically about 5-30 °, towards the horizontal plane. An advantage of this angle A1 is that the distribution of the drying air TL1 along the width BB2 of the belt 14 becomes very advantageous.
    The heating coil 26 has a width BV2 which suitably corresponds to at least 70% of the width BB2 of the belt 14. Normally, it is inappropriate for the width BV2 of the heating coil 26 to be greater than 120% of the width BB2 of the belt 14. Thus, the heating coil 26 will cover most of the width BB2 of the belt 14, and also most of its length, as described above with reference to Fig. 1.
    Seen from above, the heating coil 26 will suitably cover at least 60% of the horizontal surface of the drying section 20, which surface corresponds to the length LT2 of the drying section 20 multiplied by the width BB2 of the belt 14. It is generally inappropriate for the heating coil 26 to cover more than about 120% of the horizontal surface of the drying section 20. In the heating coil 26, the drying air TL1 is heated to typically 60-150 ° C by means of, for example, water vapor, hot oil or hot water.
    The drying air TL1 passes through the belt 14 and reaches a first exhaust air duct 32 arranged below the belt 14. The exhaust air duct 32 passes out through a first outlet 34 which is arranged in a second vertical side wall 36 in the housing 2, which side wall 36 is parallel to the first side wall 30. but arranged on the opposite side of the belts 4, 14. The exhaust air duct 32 opens into a first fan 38. This fan 38 creates the negative pressure which causes the ambient air, which forms the first flow of drying air TL1, to pass in through the inlet 28, further through the second the heating coil 26 and the belt 14, with the tree material transported thereon, and out through the exhaust air duct 32. In the exhaust air duct 32, the drying air TL1, which has passed through the tree material transported on the belt 14 and dried it, has a temperature of typically about 20-60 ° C.
    The fan 38 opens into a supply duct 40. The supply duct 40 directs the drying air from the fan 38 to a second inlet 42 which is arranged in the second vertical side wall 36 in a position located above the first belt 4. The drying air is led through the inlet 42 into the housing 2 and through the first heating coil 24 to form the second flow of drying air TL2. As shown in Fig. 2, the first heating coil 24, which is in the form of a straight block, is arranged vertically above the belt 4 and is angled relative to the belt 4 and the inlet 42. The heating coil 24 thus slopes towards the inlet 42 and forms an angle A2, which is typically about 5-30 °, towards the horizontal plane. An advantage of this angle A2 is that the distribution of the drying air TL2 along the width BB1 of the belt 4 becomes very advantageous. The heating battery 24 has a width BV1 which suitably corresponds to at least 70% of the width BB1 of the belt 4. Normally, it is inappropriate for the width BV1 of the heating coil 24 to be greater than 120% of the width BB1 of the belt 4. Thus, the heating coil 24 will cover most of the width BB1 of the belt 4, seen from above, and also most of its length, as described above with reference to Fig. 1. Seen from above, the heating coil 24 will suitably cover at least 60% of the horizontal surface of the drying section 10, which surface corresponds to the length LT1 of the drying section 10 multiplied by the width BB1 of the belt 4. In general, it is inappropriate for the heating coil 24 to cover more than 120% of the horizontal surface of the drying section 10. In the heating coil 24, the drying air TL2 is heated to typically 60-150 ° C by means of, for example, steam, hot oil or hot water.
    The drying air TL2 passes through the belt 4 and reaches a second exhaust air duct 44 arranged below the belt 4. The exhaust air duct 44 passes out through a second outlet 46 which is arranged in the second vertical side wall 36.
    The exhaust air duct 44 opens into a second fan 48, partly obscured in Fig. 2. This fan 48 creates the negative pressure which causes the drying air TL2 to pass through the inlet 42, further through the first heating coil 24 and the belt 4, with the wood material transported thereon, and out through the exhaust air duct 44. In the exhaust air duct 44, the drying air TL2, which has passed through the tree material transported on the belt 4 and dried it, has a temperature of typically about 20-60 ° C.
    The fan 48 opens into an exhaust duct 50 which releases the spent drying air into the atmosphere.
    The material M best shown in Fig. 1, which is dried in the wood material dryer 1, will have the highest temperature on the second belt 14, since the moisture content of the material M is then the lowest. This means that some volatiles can be evaporated and mixed with the drying air leaving the dryer 1 via the exhaust air duct 32 shown in Fig. 2. The drying air leaving the exhaust air duct 32 will not be discharged, however, but is led via the supply duct 40 to the first heating battery 24 where the drying air is heated from typically about 20-60 ° C to about 60-150 ° C. This method is very energy efficient, as it usually takes less energy to heat the drying air used in the drying on the second belt 14, and which is already relatively hot, to the desired drying temperature on the first belt 4, compared to if ambient air had been introduced in the second inlet 42. A further advantage is that the particles and volatile organic substances which depart from the material M on the second belt 14, and which are found in the drying air which is led away via the exhaust air duct 32, thanks to the drying air being heated again and then 11 is passed through the first belt 4, via the supply channel 40, at least partially fixed to the material M on the first belt 4, where the moisture content is higher and the temperature is lower. This reduces emissions of particles and volatile organic compounds from the dryer 1. In addition, the consumer dryer 1 has only half as much fresh ambient air according to the connection described above, compared to if fresh ambient air had also been taken in for the first heating battery.
    This means that the amount of ambient air that is affected by the drying process can be halved, which further reduces emissions. The fact that the air having the lowest moisture content, i.e. the ambient air taken in via the inlet 28, is used for drying on the second belt 14, and that the drying air having a higher moisture content, after participating in the drying on the second belt 14, is used for drying on the first belt 4 entails a countercurrent coupling, which is also very efficient from the point of view of drying and from the point of view of energy efficiency.
    The pressure drop across the respective heating coil 24, 26 during operation of the dryer 1, measured as the difference between static pressure measured just above the respective heating coil and static pressure measured just after the respective heating coil, is suitably 20-200 Pa. Such a pressure drop gives a good distribution of the drying air over the wood material to be dried, and at the same time a low energy consumption in the respective fan 38, 48. The heating batteries 24, 26 will thus function as gas distributors, which distribute the drying air TL2, TL1 over each drying section 10, 20, which reduces or completely eliminates the need for additional guide rails and similar devices for guiding the drying air in the desired direction.
    In Figs. 1 and 2, an embodiment has been described in which the heating batteries 24, 26 consist of a heating element each. It will be appreciated that it is also possible to divide each of the heating batteries 24, 26 into a plurality of modules along the length of the dryer 1, which modules are arranged in series along the respective belts 4, 14. Fig. 3 illustrates a wood material dryer 101 having the first and second belts 104, 114 of a similar type and function as belts 4, 14 to dryer 1. The dryer 101 is, with respect to the handling of drying air, divided into a total of 8 modules, of which four upper modules 160, 162, 164, and 166 supply the upper belt 104 with drying air. , and four lower modules 170, 172, 174, and 176 supply the lower belt 114 with drying air. Each upper module contains a heating battery unit, which has a similar appearance to the heating batteries 24, 26 described in Figs. 1 and 2, as well as the ducts needed to supply and remove drying air. An advantage of this embodiment is that a number of shorter heating battery units can be used to together form heating batteries which extend along the respective belts 104, 114. This is especially advantageous if the dryer is to be long, as it can be difficult to manufacture and mount a heating coil that lasts the entire length. It is also possible to use several fans, for example a fan which serves the modules 170 and 172, a fan which serves the modules 174 and 176, a fan which serves the modules 160 and 162, and a fan which serves the modules 164 and 166. The basic structure for this dryer 101 is the same as for dryer 1, except that the dryer 101 is divided into modules, each of which has its own heating battery unit and ducts. Thus, an optional cross-section along the dryer 101 has the principal appearance illustrated in Fig. 2.
    Fig. 4 illustrates a further alternative embodiment in the form of a wood material dryer 201. The wood material dryer 201 is shown in a section corresponding to the section in which the wood material dryer 1 is illustrated in Fig. 2. Like the wood material dryer 1, the wood material dryer 201 also has a housing 202 in which a first endless belt 204 and a second endless belt 214 have been arranged in a similar manner as the corresponding belts 4 and 14, respectively. These belts 204, 214 are gas permeable. Extending along the first belt 204 is a first heating coil 224, and along the second belt 214 extends a second heating coil 226. The heating coils 224, 226 have substantially the same extent relative to the respective drying portion as described above with respect to the drying portions 10 and 20. The measurement of material by the wood material dryer 201 will essentially take place according to the principles described above with reference to Fig. 1 regarding the wood material dryer 1.
    What distinguishes the wood material dryer 201 from the wood material dryer 1 described above is that the wood material dryer 201 is provided with an air-to-air heat exchanger 203. The air-to-air heat exchanger 203 is mounted on a side wall 236 in the housing 202. Ambient air to be heated in the second heating coil 226 to form a first flow of drying air TL1 is passed through the air heat exchanger 203 to be preheated. The ambient air is then led through the housing 205 on the outside of the pipes 207. The ambient air temperature can then be increased by typically 10-30 ° C, from the initial temperature of for example -10 to + 25 ° C, ie the ambient air is preheated, depending on the initial temperature of the ambient air and the temperature of the spent drying air, to a temperature of typically 0 ° C to 55 ° C. The ambient air then passes through an air inlet 228 in the side wall 236 and then dries the wood material on the belt 214 in accordance with the principles described above with reference to Fig. 1 and Fig. 2. The drying air leaves the dryer 201 via an exhaust air duct 232 and is then passed, via a fan 238, to the first heating coil 224 where the drying air is heated to form a second drying air fl deserted TL2. The second drying air stream TL2 dries the material on the belt 204, and then leaves the dryer via an exhaust air duct 244. This duct 244 leads the spent drying air, which is humid and has a temperature of typically 20-60 °, to the heat exchanger 203. In the air-air heat exchanger 203 the spent drying air is led inside the heat exchanger tubes 207. Thus, part of the remaining energy content of the spent drying air, which leaves the dryer 201 via the duct 244, will be used to preheat the ambient air flowing outside the pipes 207, before the ambient air is used for drying.
    This results in a further improved energy efficiency. The spent drying air is then passed on from the heat exchanger 203 to a fan 248 and is then discharged via an exhaust duct 250.
    The spent drying air, which is led through the tube 207 of the heat exchanger 203, will be cooled by the ambient air flowing outside the tubes 207.
    Since the spent drying air is already at, or at least close to, saturation with respect to its water vapor content before this cooling, water vapor will often condense out inside the tubes 207. Along with the water vapor, at least part of the consumed drying air content of organic compounds to condense out. This condensate is trapped below the heat exchanger 203 in a condensate collector 209 and then discharged via a line 211 to a water treatment plant (not shown). There is further purification of the drying air leaving the wood material dryer 201. It is understood that a number of modifications of the above-described embodiments are possible within the scope of the invention, as defined by the appended claims.
    It has been described above, for example, that the first inlet 28 is arranged in a first side wall 30, and that the second inlet 42 is arranged in an opposite second side wall 36. It will be understood that both inlets can be arranged in the same side wall. For example, the inlet 28 could alternatively be arranged in the side wall 36, the second heating coil 26 being suitably given the opposite slope to what is indicated in Fig. 2.
    The heating batteries 24, 26 described above can be of various types known per se which are suitable for heating drying air. An example of a suitable type are heating batteries which are provided with pipes inside which steam, typically with a pressure of 2-10 bar absolute pressure, is conducted. The drying air flows on the outside of the pipes and absorbs heat from the steam inside the pipes. It is also possible to heat the drying air with the aid of hot liquid, eg water or oil with a temperature of around 70-150 ° C, which liquid is led in pipes or ducts on the outside of which the drying air flows.
    It is described above that the entire first flow of drying air TL1 used for drying on the second drying section 20 is reheated and used as the second flow of drying air TL2 for drying on the first drying section 10. Although this is often preferred, it may also be preferred. there are times when it is not possible or desirable to utilize the entire first flow of drying air TL1 when generating the second flow of drying air TL2. Normally, however, at least 50% of the first flow of drying air TL1, and more preferably at least 90% of the first flow of drying air TL1, should be used to generate the second flow of drying air TL2.
    It is described above, with reference to Fig. 4, that an air-to-air heat exchanger 203 with tubes is used for heat recovery. It will be appreciated that other types of air-to-air heat exchangers may be used for this purpose.
    权利要求:
    Claims (14)
    [1]
    A wood material dryer having a first gas permeable belt (4) on which wood material to be dried can be transported, and a second gas permeable belt (14) on which wood material to be dried can be transported, the second belt (14) being arranged below it first belt (4) and is arranged to receive material which is transported over the first belt (4) and which falls down therefrom, characterized in that the wood material dryer (1) has a first heating coil (24), which is arranged above the first belt (4) and is arranged to heat air intended to dry wood material transported on the first belt (4), and a second heating coil (26), which is arranged above the second belt (14) and is arranged to heating air intended to dry wood material transported on the second belt (14), the wood material dryer (1) having at least one channel (32, 40) arranged to conduct drying air which has passed through the second heating coil (26) and the second belt (14) to the first heating coil (24) and further through the first belt (4).
    [2]
    A wood material dryer according to claim 1, wherein the first belt (4) has a first drying portion (10) arranged to support and transport wood material to be dried, the first heating coil (24) extending along at least 60% of the first length of the drying section (10) (LT1).
    [3]
    Wood material dryer according to any one of the preceding claims, wherein the second belt (14) has a second drying portion (20) arranged to support and transport wood material to be dried, the second heating coil (26) extending along at least 60% of the length of the second drying section (20) (LT2).
    [4]
    Wood material dryer according to one of the preceding claims, in which the first heating coil (24) has a width (BV1) which corresponds to at least 70% of the width (BB1) of the first strip (4).
    [5]
    A wood material dryer according to any one of the preceding claims, wherein the second heating coil (26) has a width (BV2) corresponding to at least 70% of the width (BB2) of the second belt (14). in. .i '~ ll1, .f3, “ï 10 15 20 25 30 16
    [6]
    Wood material dryer according to one of the preceding claims, in which the first and second heating batteries (24, 26) and the first and second strips (4, 14) are arranged vertically one above the other in a housing (2).
    [7]
    A wood material dryer according to claim 6, wherein a first inlet (28) for supplying drying air (TL1) to the second heating coil (26) is arranged in a vertical sludge wall (30) in said housing (2), the second heating coil (2) 26) is inclined towards the first inlet (28) and forms an angle (A1) towards the horizontal plane which is 5-30 °.
    [8]
    Wood material dryer according to claim 6 or 7, wherein a second inlet (42) for supplying drying air (TL2) to the first heating coil (24) is arranged in a vertical side wall (36) in said housing (2), wherein the first the heating coil (24) is inclined towards the second inlet (42) and forms an angle (A2) towards the horizontal plane which is 5-30 °.
    [9]
    Wood material dryer according to any one of the preceding claims, in which a heat exchanger (203) is arranged to heat exchange at least a part of the drying air which has been used for drying on the first belt (204) with at least a part of the air which is intended to be used. for drying on the second belt (214).
    [10]
    A method of drying wood material in a wood material dryer, in which the wood material is first dried and transported on a first gas permeable belt (4) and then allowed to fall on a second gas permeable belt (14) arranged below the first belt (4) on which the wood material is further transported and dried, characterized in that the wood material dryer (1) has a first heating coil (24), which is arranged above the first belt (4), and a second heating coil (26), which is arranged above the second belt (14). ), wherein drying air (TL1) is first passed through the second heating coil (26) and then through the second belt (14) while drying wood material transported thereon, at least a part of the drying air (TL2) passing through the second belt (26). 14) is collected and passed through the first heating coil (24) and then through the first belt (4) during drying of wood material transported thereon.
    [11]
    A method according to claim 10, wherein the pressure drop in the drying air over the first heating coil (24) is 20 - 200 Pa. 17
    [12]
    A method according to claim 10 or 11, wherein the pressure drop in the drying air over the second heating coil (26) is 20 - 200 Pa.
    [13]
    A method according to any one of claims 10-12, wherein the tree material falls freely and substantially vertically downwards from the first band (4) to the second band (14).
    [14]
    A method according to any one of claims 10-13, wherein at least a part of the drying air which has been used for drying on the first belt (204) is heat exchanged with at least a part of the air which is intended to be used for drying on the second belt (214).
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    同族专利:
    公开号 | 公开日
    SE534174C2|2011-05-17|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP3141852A1|2015-08-17|2017-03-15|Stela Laxhuber GmbH|Belt dryer with two drying levels|
    CN106017034A|2016-05-13|2016-10-12|安徽瑞丝环保能源有限公司|Straw drying and smashing device|
    法律状态:
    2016-11-29| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE0900475A|SE534174C2|2009-04-09|2009-04-09|Device and method of drying tree material|SE0900475A| SE534174C2|2009-04-09|2009-04-09|Device and method of drying tree material|
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