Waste heat recovery device for corrugated board production

Abstract

The invention relates to a waste heat recovery device for corrugated board production, and relates to the field of corrugated board production, the waste heat recovery device comprises a drying room, one side wall of the drying room is fixedly communicated with two ventilation pipes, one side of the drying room is provided with air heating equipment, and the other end of each ventilation pipe is communicated with the air heating equipment; each ventilation pipe is connected with a filtering mechanism, each filtering mechanism comprises a dust collecting box detachably connected with the lower surface wall of the corresponding ventilation pipe, the upper end of each dust collecting box is open and communicated with the corresponding ventilation pipe, each filtering mechanism further comprises a telescopic filtering net piece hinged to the inner top wall of the corresponding ventilation pipe, and the bottom end of each telescopic filtering net piece is slidably connected with the lower surface wall of the corresponding ventilation pipe. The telescopic filter net pieces are located over the corresponding dust collecting boxes and gradually incline in the gas flowing direction from top to bottom, a draught fan is installed on each ventilation pipe, and a driving mechanism for driving the lower ends of the telescopic filter net pieces to move is connected to the telescopic filter net pieces. The dust collection device has the effect of reducing the situation that dust is extracted and recycled.

Description

Technical Field

[0001] This application relates to the field of corrugated cardboard production, and particularly to a waste heat recovery device for corrugated cardboard production. Background Art

[0002] Corrugated cardboard is also known as corrugated board. It is composed of at least one layer of corrugated paper and one layer of box board paper (also called box board paper), and has good elasticity and extensibility. It is mainly used for manufacturing cartons, the sandwich of cartons, and other packaging materials for fragile goods. It is widely used in the paper-making industry.

[0003] In the processing of corrugated cardboard, glue is required. Therefore, the corrugated paper and box board paper in the composite corrugated cardboard will be soaked and the strength will not be high. In the related art, generally, the corrugated cardboard will be put into a drying device to blow hot air for drying the corrugated cardboard. In order to recycle the hot air, usually, the hot air blown out by the drying device is extracted, and the hot air is reheated and introduced into other devices or the corrugated cardboard is blown with hot air again for drying.

[0004] However, when extracting the hot air blown out by the drying device, it is possible that dust is also extracted and recycled. Summary of the Invention

[0005] In order to reduce the occurrence of dust being extracted and recycled, this application provides a waste heat recovery device for corrugated cardboard production.

[0006] A waste heat recovery device for corrugated cardboard production provided by this application adopts the following technical solution: A waste heat recovery device for corrugated cardboard production includes a drying room. Two ventilation pipes are fixedly connected and communicated with one side wall of the drying room. An air heating device is arranged on one side of the drying room. The other end of each ventilation pipe is communicated with the air heating device. A filtering mechanism is connected to each ventilation pipe. The filtering mechanism includes a dust collection box detachably connected to the lower surface wall of the ventilation pipe. The upper end of the dust collection box is open and communicated with the ventilation pipe. It also includes a telescopic filter member hinged to the inner top wall of the ventilation pipe. The bottom end of the telescopic filter member is slidably connected to the lower surface wall of the ventilation pipe, and the telescopic filter member is located directly above the corresponding dust collection box. The telescopic filter member is inclined gradually from top to bottom along the direction of gas flow. A fan is installed on each ventilation pipe. A driving mechanism for driving the lower end of the telescopic filter member to move is connected to the telescopic filter member.

[0007] By adopting the above technical solution, effective filtration of the dust-containing waste gas generated during the corrugated cardboard production process and recovery and utilization of the hot air can be achieved. Specifically, the air heating device passes hot air into the drying chamber through one of the air pipes, and the hot air dries the corrugated cardboard in the drying chamber. The waste gas in the drying chamber is conveyed back into the air heating device again through the other air pipe, and the air heating device reheats the waste gas with temperature, thus realizing waste heat recovery.

[0008] When the air flow passes through each air pipe, the telescopic filter element can intercept the dust in the waste gas, and the dust slides down along the telescopic filter element into the dust collection box for collection, thereby reducing the risk of pipeline blockage. And it ensures that the gas entering the air heating device is cleaner, improves the thermal energy conversion efficiency, and reduces the occurrence of dust being extracted and recovered. At the same time, the lower end of the telescopic filter element is slidably connected to the air pipe, so that the inclination angle of the telescopic filter element can be adjusted, which is convenient for the dust to fall into the dust collection box along the telescopic filter element with different inclination angles.

[0009] Preferably, the fans installed on each of the air pipes are reversible fans.

[0010] By adopting the above technical solution, the reversible fan can change the wind direction. When one of the air pipes is used as the suction pipe and the other air pipe is used as the blowing pipe, the corrugated cardboard near the suction pipe in the drying chamber is easier to be dried. At this time, by adjusting each reversible fan, the air flow directions in the two ventilation pipes are changed, so as to facilitate the drying of the corrugated cardboard on the other side in the drying chamber.

[0011] Preferably, a guide groove is formed at the bottom end of the telescopic filter element, and a guide rod is fixedly connected to the opening where the air pipe communicates with the dust collection box. The guide rod is arranged along the direction of gas flow, and the guide groove is slidably connected to the guide rod.

[0012] By adopting the above technical solution, the guide groove at the bottom of the telescopic filter element and the guide rod on the air pipe are in sliding fit, which can ensure the stability and accuracy of the telescopic filter element during the movement process.

[0013] Preferably, a transition pipe is fixedly connected and communicated with the lower surface wall of each air pipe. The transition pipe is detachably connected to a corresponding dust collection box. A blocking mechanism is installed in the transition pipe. The blocking mechanism includes a plurality of rotating shafts rotatably connected to the inside of the transition box. A single plate is fixedly connected to the side wall of each rotating shaft. The plurality of single plates are arranged horizontally and form a blocking plate for blocking the transition pipe. The driving mechanism is used to drive each rotating shaft to rotate.

[0014] By adopting the above technical solution, a rotatable plugging mechanism is arranged in the transition pipe. The plugging mechanism is composed of multiple single plates arranged horizontally, and can flexibly control the opening and closing of the transition pipe. When cleaning or maintenance is required, the driving mechanism can drive the rotating shaft to rotate, so that the plugging plate composed of single plates closes the transition pipe, effectively reducing the entry of impurities into the ventilation pipe. At this time, the dust collection box can be detached and cleaned. After the dust collection box is installed, the driving mechanism drives each rotating shaft to rotate, so that each single plate rotates to a vertical setting. At this time, the dust collection box is internally communicated with the ventilation pipe through the transition pipe, facilitating the collection of dust.

[0015] Preferably, the driving mechanism includes a driving shaft fixedly connected to the upper end of the telescopic filter element. Both ends of the driving shaft are rotatably connected to the inner wall of the ventilation pipe. A driving motor is fixedly connected to the outer side wall of the ventilation pipe. The output shaft of the driving motor is coaxially fixed to one end of the driving shaft. The same end of each rotating shaft penetrates the side wall of the ventilation pipe. One end of each rotating shaft extending out of the ventilation pipe is fixedly connected with a sprocket. Multiple sprockets are connected by a chain. The output shaft of the driving motor is also connected to one of the rotating shafts by a sprocket chain.

[0016] By adopting the above technical solution, the driving motor drives the driving shaft to rotate, thereby realizing the movement of the telescopic filter element and facilitating the adjustment of the inclination direction of the telescopic filter element. When adjusting the wind direction of the reversible fan, the driving motor drives the telescopic filter element to rotate at the same time until the telescopic filter element gradually inclines along the gas flow direction from top to bottom, facilitating the dust to smoothly enter the dust collection box along the telescopic filter element. At the same time, the power is transmitted to each rotating shaft through the sprocket chain transmission structure, ensuring the coordinated operation of multiple single plates in the plugging mechanism, and ensuring that the plugging mechanism connected to the exhaust pipe is in an open state, facilitating the dust in the exhaust gas extracted from the drying room to enter the dust collection box in time for collection. And the plugging mechanism connected to the blowing pipe of the ventilation pipe is in a closed state, facilitating the disassembly and cleaning of the dust collection box.

[0017] Preferably, a vertical through hole and an arc hole are formed in one side wall of the dust collection box. One end of the arc hole is communicated with the vertical through hole. The upper end of the vertical through hole penetrates the dust collection box. The lower end of the transition pipe is inserted into the dust collection box, and each outer side wall of the transition pipe is closely attached to the corresponding inner side wall of the dust collection box. A locking rod is slidably connected to one outer side wall of the transition pipe. The locking rod is inserted into the arc hole and slides along the arc hole.

[0018] By adopting the above technical solution, when the dust collection box needs to be cleaned or replaced, the locking rod can be pulled to make the locking rod slide along the arc hole and enter the vertical through hole, and then the dust collection box can be pulled downward, thereby completing the disassembly and separation of the dust collection box and the transition pipe, improving the maintenance efficiency. At the same time, the design structure is simple and reliable, facilitating operation while ensuring the sealing performance, and effectively reducing the time cost of equipment maintenance.

[0019] Preferably, an arc-shaped groove is formed in an outer side wall of the transition pipe. A first magnet block is slidably connected in the arc-shaped groove and fixedly connected to a locking rod. One end of one of the single plates is fixedly connected to a second magnet block. The second magnet block and the first magnet block are both pressed against the side wall of the transition pipe and adsorb to each other. Rotation of the single plate drives the locking rod to rotate through the second magnet block and the first magnet block.

[0020] By adopting the above technical solution, the design of the first magnet block and the second magnet block realizes the linkage control of the locking rod during the rotation of the single plate. Specifically, during the rotation of the single plate, the adsorption between the second magnet block and the first magnet block can drive the locking rod to rotate synchronously, so as to ensure reliable locking or unlocking between the transition pipe and the dust collection box. At the same time, the sliding structure in the arc-shaped groove ensures the stability and accuracy of the movement path of the first magnet block, effectively improving the operation convenience and sealing performance of the entire device.

[0021] Preferably, the telescopic filter member includes a hollow mounting plate. Mounting holes are formed in both side walls of the mounting plate. A filter screen is fixedly connected in each mounting hole. An inlet is formed in the bottom wall of the mounting plate. A filter plate is slidably inserted into the inlet. The filter plate is located between the two filter screens. A guide groove is formed in the bottom wall of the filter plate.

[0022] By adopting the above technical solution, the function of efficiently filtering the gas in the ventilation pipe is realized. Specifically, the filter screens on both sides of the mounting plate can effectively intercept impurity particles in the gas, and the filter plate slidably inserted into the inlet at the bottom of the mounting plate further enhances the filtering effect and is convenient for taking out, cleaning or replacing. The sliding connection between the filter plate and the mounting plate realizes the telescopic function of the telescopic filter member.

[0023] In summary, the present application includes at least one of the following beneficial technical effects: 1. Ensure that the gas entering the air heating device is cleaner, improve the heat energy conversion efficiency, and reduce the occurrence of dust being extracted and recycled; 2. Adopt the telescopic filter member design, cooperate with the driving mechanism to realize the automatic cleaning function, ensure that the filter screen is easy to maintain and does not affect the gas flow efficiency due to blockage; 3. Set a reversible fan to adjust the gas flow direction according to actual needs, further optimize the heat recovery process and enhance the drying effect of the corrugated cardboard. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the overall structure of the waste heat recovery device shown in the embodiment of the present application.

[0025] Figure 2 is a schematic diagram of the structure of the filtering mechanism shown in the embodiment of the present application.

[0026] Figure 3 It is a schematic structural diagram showing the driving mechanism in an embodiment of the present application.

[0027] Figure 4 It is a schematic structural diagram showing the locking between the dust collection box and the ventilation pipe in an embodiment of the present application.

[0028] Figure 5 It is a schematic structural diagram showing the plugging mechanism in an embodiment of the present application.

[0029] Explanation of reference numerals: 1, drying room; 2, ventilation pipe; 21, reversible fan; 3, air heating device; 4, filtering mechanism; 41, dust collection box; 411, arc-shaped hole; 412, vertical through hole; 42, telescopic filter element; 421, mounting plate; 422, filter screen; 423, filter plate; 4231, guide groove; 424, guide rod; 43, locking rod; 431, first magnet block; 5, transition pipe; 51, arc-shaped groove; 6, driving mechanism; 61, driving shaft; 62, driving motor; 63, sprocket; 64, chain; 7, plugging mechanism; 71, rotating shaft; 72, single plate; 721, second magnet block. Detailed implementation manners

[0030] The following further elaborates on the present application in conjunction with the attached Figures 1-5 drawings.

[0031] An embodiment of the present application discloses a waste heat recovery device for corrugated board production. Referring to Figure 1 and Figure 2 , the waste heat recovery device includes a drying room 1, two ventilation pipes 2, an air heating device 3, and a filtering mechanism 4 connected to each ventilation pipe 2. The air heating device 3 is fixedly connected and communicated with the two ventilation pipes 2. One end of each ventilation pipe 2 away from the air heating device 3 is fixedly connected to different side walls of the drying room 1, and each ventilation pipe 2 is communicated with the inside of the drying room 1. The air heating device 3 is provided with a resistance wire, and an air inlet pipe communicating with the outside is connected to the air heating device 3, and a valve is installed on the air inlet pipe. A fan is installed on each ventilation pipe 2.

[0032] One ventilation pipe 2 is used as an exhaust pipe, and the other ventilation pipe 2 is used as a blowing pipe. Start the fans on each ventilation pipe 2. At this time, external air enters the air heating device 3 along the air inlet pipe, and the resistance wire heats the air in the air heating device 3. Then the hot air enters the drying room 1 along the exhaust pipe, so as to blow hot air to dry the corrugated board in the drying room 1. At the same time, the hot air in the drying room 1 enters the air heating device 3 again along the suction pipe, which is convenient for recovering waste heat.

[0033] The fans installed on each ventilation pipe 2 are all reversible fans 21. A reversible fan 21 is a fan that can achieve forward and reverse rotation control. It consists of an outer rotor, an inner rotor, and a motor. When the motor is in the forward rotation state, the inner and outer rotors rotate simultaneously, generating a forward air flow; when the motor rotates in the reverse direction, the inner and outer rotors also rotate in the reverse direction, generating a reverse air flow. By adjusting the forward or reverse rotation of each reversible fan 21 in this way, different ventilation pipes can be used as blowing pipes, and the corrugated cardboard set near the blowing pipes in the drying room 1 is easier to dry. Intermittently adjusting the wind direction of the ventilation pipes facilitates the relatively uniform drying of the corrugated cardboard in the drying room 1.

[0034] Referring to Figure 2 and Figure 3 , the filtering mechanism 4 includes a dust collection box 41 detachably connected to the lower surface wall of each ventilation pipe 2, and a telescopic filter element 42 hinged to the inner top wall of the ventilation pipe 2. The telescopic filter element 42 is located directly above the dust collection box 41. During the process of air flow passing through the ventilation pipe 2, the dust mixed in the air flow is intercepted by the telescopic filter element 42 and slides down along the telescopic filter element 42 into the dust collection box 41.

[0035] A transition pipe 5 is fixedly connected and communicated with the lower surface wall of each ventilation pipe 2. The lower end of the transition pipe 5 is inserted into the interior of the dust collection box 41, and each outer side wall of the transition pipe 5 is in contact with the corresponding inner side wall of the dust collection box 41.

[0036] Referring to Figure 3 and Figure 4 , an arc-shaped groove 51 is formed in one outer side wall of each transition pipe 5. The shape of the arc-shaped groove 51 is a quarter circle. A locking rod 43 is slidably connected in the arc-shaped groove 51. An arc-shaped hole 411 and a vertical through hole 412 are formed in one side wall of the dust collection box 41. The lower end of the vertical through hole 412 is communicated with one end of the arc-shaped hole 411, and the upper end vertically penetrates through the dust collection box 41. The locking rod 43 is slidably inserted into the arc-shaped hole 411.

[0037] When it is necessary to disassemble the dust collection box 41 and the transition pipe 5, slide the locking rod 43 along the arc-shaped hole 411 and the arc-shaped groove 51 towards the direction close to the vertical through hole 412 until the locking rod 43 slides into the vertical through hole 412. Then move the dust collection box 41 downward until the dust collection box 41 is separated from the transition pipe 5. At this time, the disassembly and separation of the dust collection box 41 and the transition pipe 5 are completed.

[0038] Referring to Figure 2 and Figure 3, the telescopic filter element 42 is gradually inclined downward along the gas flow direction from top to bottom. The telescopic filter element 42 includes a hollow mounting plate 421. An inlet is provided on the bottom surface of the mounting plate 421, and a filter plate 423 is slidably inserted into the inlet. Mounting holes communicating with the inside of the mounting plate 421 are provided on both outer side walls of the mounting plate 421, and a filter screen 422 is fixedly connected in each mounting hole. The filter plate 423 is located between the two filter screens 422. A guide groove 4231 is provided at the bottom end of the filter plate 423. A guide rod 424 is fixedly connected to the connection part of the transition pipe 5 and the ventilation pipe. The guide rod 424 is arranged along the gas flow direction, and the guide groove 4231 is slidably connected with the guide rod 424. A driving mechanism 6 for driving the lower end of the telescopic filter element 42 to move is connected to the telescopic filter element 42.

[0039] When adjusting the reversible fan 21 to change the gas flow direction, the telescopic filter element 42 is adjusted to rotate through the driving mechanism 6, so as to drive the telescopic filter element 42 to be arranged in the opposite inclination direction, ensuring that the dust driven by the gas flow can always enter the dust collection box 41 along the telescopic filter element 42.

[0040] Refer to Figure 2 and Figure 3 , a blocking mechanism 7 for blocking the transition pipe 5 is installed in each transition pipe 5. The blocking mechanism 7 includes a plurality of rotating shafts 71 rotatably connected inside the transition pipe 5. The plurality of rotating shafts 71 are arranged parallel to each other, and a single plate 72 is fixedly connected to each rotating shaft 71. When each single plate 72 is arranged horizontally, each single plate 72 contacts the adjacent single plate 72 to jointly form a blocking plate, and the blocking plate horizontally blocks the transition pipe 5.

[0041] The driving mechanism 6 includes a driving shaft 61 fixedly connected to the upper end of the mounting plate 421. Both ends of the driving shaft 61 are rotatably connected to the inner wall of the ventilation pipe. A driving motor 62 is fixedly connected to an outer side wall of the ventilation pipe. The output shaft of the driving motor 62 penetrates through the ventilation pipe and is coaxially fixed to one end of the driving shaft 61.

[0042] One end of each rotating shaft 71 close to the driving motor 62 penetrates through the ventilation pipe and is coaxially fixed with a sprocket 63. The plurality of sprockets 63 are connected by a chain 64. The output shaft of the driving motor 62 is also connected to one of the rotating shafts 71 by a sprocket 63 and a chain 64.

[0043] Start the driving motor 62. The output group of the driving motor 62 drives the driving shaft 61 to rotate, so as to drive the telescopic filter element 42 to rotate in the direction close to the other end of the dust collection box 41. At the same time, the output shaft of the driving motor 62 drives each rotating shaft 71 to rotate through the sprocket 63 and the chain 64, and then drives each single plate 72 to rotate to the horizontal or vertical position.

[0044] Refer to Figure 4 andFigure 5 , a magnet block 431 is slidably connected in the arc-shaped groove 51, and one end of the magnet block 431 is fixedly connected to one end of the locking rod 43. One end of one single board 72 is fixedly connected to a magnet block 721. The magnet block 721 contacts the inner side wall of the ventilation pipe, and the magnet block 431 and the magnet block 721 attract each other. When the single board 72 rotates from the horizontal to the vertical setting, the magnet block 721 drives the magnet block 431 to move away from the vertical through hole 412 by magnetic force, so as to complete the locking between the transition pipe 5 and the dust collection box 41.

[0045] The implementation principle of the waste heat recovery device for corrugated cardboard production in the embodiment of the present application is as follows: Start the fans on each ventilation pipe, so that the heated hot air enters the drying box along one of the ventilation pipes 2, and then returns to the air heating device 3 along the other ventilation pipe 2, realizing the recycling of the hot air. Intermittently adjust the air flow direction of each ventilation pipe, and at the same time start the driving motor 62. The driving motor 62 drives the telescopic net plate member to rotate, so that the telescopic net plate member is always inclined from top to bottom along the air flow direction, so as to facilitate the dust brought by the air flow to smoothly fall into the dust collection box 41 for collection.

[0046] The above are all the preferred embodiments of the present application, and the protection scope of the present application is not limited by this. Therefore, all equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A waste heat recovery device for corrugated board production, characterized in that: The drying room (1) comprises two ventilation pipes (2) fixed to and connected to one side wall of the drying room (1); an air heating device (3) is provided on one side of the drying room (1); the other end of each ventilation pipe (2) is connected to the air heating device (3); each ventilation pipe (2) is connected to a filtering mechanism (4); the filtering mechanism (4) comprises a dust collecting box (41) detachably connected to the lower surface wall of the ventilation pipe (2); the upper end of the dust collecting box (41) is open and connected to the ventilation pipe (2); It also comprises a telescopic filter element (42) hinged to the inner top wall of the ventilation pipe (2), the bottom end of the telescopic filter element (42) being slidably connected to the lower surface wall of the ventilation pipe (2), and the telescopic filter element (42) being located directly above the corresponding dust collecting box (41), the telescopic filter element (42) being gradually inclined from top to bottom along the direction of gas flow, each of the ventilation pipes (2) being installed with a fan, and the telescopic filter element (42) being connected to a driving mechanism (6) for driving the lower end of the telescopic filter element (42) to move.

2. A waste heat recovery device for corrugated board production according to claim 1, characterized in that: The fan installed on each ventilation pipe (2) is a reversible fan (21).

3. A waste heat recovery device for corrugated board production according to claim 2, characterized in that: A guide groove (4231) is provided at the bottom end of the telescopic filter element (42); a guide rod (424) is fixedly connected to the opening of the ventilation pipe (2) communicating with the dust collecting box (41); the guide rod (424) is arranged along the direction of gas flow, and the guide groove (4231) is slidably connected to the guide rod (424).

4. The waste heat recovery device for corrugated board production according to claim 2, characterized in that: A transition pipe (5) is fixed to and communicated with the lower surface wall of each ventilation pipe (2); the transition pipe (5) is detachably connected to a corresponding dust collecting box (41); a blocking mechanism (7) is installed in the transition pipe (5); the blocking mechanism (7) comprises a plurality of rotating shafts (71) rotatably connected to the interior of the transition box; a single plate (72) is fixedly connected to the side wall of each rotating shaft (71); the plurality of single plates (72) are transversely arranged and constitute a blocking plate for blocking the transition pipe (5); and the driving mechanism (6) is used to drive each rotating shaft (71) to rotate.

5. A waste heat recovery device for corrugated board production according to claim 4, characterized in that: The driving mechanism (6) comprises a driving shaft (61) fixedly connected to the upper end of the telescopic filter element (42), both ends of the driving shaft (61) being rotatably connected to the inner wall of the ventilation pipe, the outer wall of the ventilation pipe being fixedly connected to a driving motor (62), the output shaft of the driving motor (62) being coaxially fixed to one end of the driving shaft (61), the same end of each rotating shaft (71) passing through the side wall of the ventilation pipe, one end of each rotating shaft (71) extending out of the ventilation pipe being fixedly connected to a sprocket (63), the plurality of sprockets (63) being connected to each other via a chain (64), and the output shaft of the driving motor (62) being connected to one of the rotating shafts (71) via a sprocket (63) and a chain (64).

6. A waste heat recovery device for corrugated board production according to claim 5, characterized in that: A vertical through hole (412) and an arc-shaped hole (411) are formed on one side wall of the dust box (41); one end of the arc-shaped hole (411) is in communication with the vertical through hole (412); the upper end of the vertical through hole (412) passes through the dust box (41); the lower end of the transition tube (5) is inserted into the dust box (41); each outer side wall of the transition tube (5) is tightly attached to a corresponding inner side wall of the dust box (41); a locking rod (43) is slidably connected to an outer side wall of the transition tube (5); the locking rod (43) is plugged into the arc-shaped hole (411) and slides along the arc-shaped hole (411).

7. A waste heat recovery device for corrugated board production according to claim 6, characterized in that: An outer wall of the transition tube (5) is provided with an arc-shaped groove (51), a magnet block 1 (431) is slidably connected in the arc-shaped groove (51), the magnet block 1 (431) is fixedly connected to the locking rod (43), one end of one of the single plates (72) is fixedly connected to a magnet block 2 (721), the magnet block 2 (721) and the magnet block 1 (431) are both pressed against the side wall of the transition tube (5) and are attracted to each other, and the single plate (72) rotates to drive the locking rod (43) to rotate through the magnet block 2 (721) and the magnet block 1 (431).

8. The waste heat recovery device for corrugated board production according to claim 3, characterized in that: The telescopic filter element (42) comprises a hollow mounting plate (421), both side walls of the mounting plate (421) are provided with mounting holes, a filter (422) is fixedly connected in each mounting hole, an inlet is provided in the bottom wall of the mounting plate (421), a filter plate (423) is slidably inserted in the inlet, the filter plate (423) is located between the two filter screens (422), and the guide groove (4231) is provided in the bottom wall of the filter plate (423).

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