Waste heat recovery energy-saving device for industrial boiler

Abstract

The utility model relates to the technical field of waste heat recovery, and discloses a waste heat recovery energy-saving device for an industrial boiler, which comprises a heat recovery box, two air inlet and outlet pipes and two water inlet and outlet pipes, one side of the heat recovery box is connected with a reversing mechanism, and the output end of the reversing mechanism penetrates through the outer wall of the heat recovery box and is connected with a moving assembly. The lower end of the moving assembly faces the interior of the heat recovery box, the upper end of the moving assembly is connected with an air inlet and outlet pipe located above the heat recovery box, and a supporting plate is fixedly connected to the inner wall of the upper end of the heat recovery box. According to the waste heat recovery energy-saving device for the industrial boiler, the partition plate and the supporting plate are arranged between the two air inlet and outlet pipes of the heat recovery box, and the two filtering assemblies are arranged in the supporting plate, so that when tail gas is introduced into the heat recovery box, impurities in the tail gas can be filtered through the filtering assemblies; therefore, large impurities contained in the tail gas can be filtered out, the influence on the water pipe is reduced, the heat exchange time is prolonged, and the heat exchange efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a waste heat recovery technical field, concretely is a waste heat recovery energy -conserving device for industrial boiler. BACKGROUND

[0002] Industrial boiler is a kind of closed container for generating steam or hot water, mainly used for heating, drying, evaporation and power supply in industrial production process. After the combustion of boiler, a large amount of waste gas will be produced, which usually contains high heat. In order to reuse these heat for production process or convert it into other forms of energy, heat recovery is often carried out.

[0003] At present, the patent with the announcement number CN221349792U discloses a boiler waste heat recovery device, which comprises a recovery tank, a support leg fixedly installed on the top of the recovery tank, a water inlet fixedly installed on the front end outer wall of the recovery tank, a water outlet fixedly installed on the left side outer wall of the recovery tank, a water pipe fixedly installed between the water inlet and the water outlet, an air inlet fixedly installed on the top of the recovery tank, and a rectangular box fixedly installed on the left side outer wall of the recovery tank. The boiler waste heat recovery device drives the first rotating shaft by the motor, so that the first rotating shaft drives the semispherical block to continuously reciprocate up and down through the first rectangular plate, the second rectangular plate and the round rod to knock the outer wall of the water pipe, thereby vibrating the dust attached to the outer wall of the water pipe, greatly improving the heat conduction performance of the water pipe and the utilization rate of flue gas, and saving the cost.

[0004] However, the above-mentioned device still has the following problems in actual use: the boiler tail gas contains a large amount of particulate matter and floating matter, which will adhere to the surface of the pipeline after contacting with the recovery pipeline, and will affect the heat exchange efficiency of the pipeline after a long time. Utility model content

[0005] In view of the deficiencies of the prior art, the utility model provides a waste heat recovery energy-saving device for industrial boiler, which can filter the boiler tail gas entering the heat recovery tank.

[0006] To achieve the above object, the utility model provides following technical scheme: A waste heat recovery energy -conserving device for industrial boiler, including heat recovery tank, two inlet and outlet air pipes of installing on the upper and lower ends of heat recovery tank and two inlet and outlet water pipes of installing on the front and back sides of heat recovery tank, the side of heat recovery tank is connected with the reversing mechanism, the output of reversing mechanism penetrates the outer wall of heat recovery tank and is connected with mobile assembly, the lower end of mobile assembly is towards heat recovery tank inside, the upper end of mobile assembly is connected with the inlet and outlet air pipe of being located above heat recovery tank, the inner wall of heat recovery tank upper end is fixedly connected with support plate, the upper surface of support plate middle part is fixedly connected with partition plate, mobile assembly is located above partition plate, the both sides of support plate located at the both sides of partition plate all are penetrated and are provided with filter mouth, the upper surface of support plate is connected with two filter assemblies, two filter assemblies are respectively matched with two filter mouths and are aligned, the both sides of heat recovery tank are all connected with cleaning mechanism, the one end of two cleaning mechanisms adjacent is all located in heat recovery tank inside, and two cleaning mechanisms are respectively matched with two filter assemblies and are aligned.

[0007] Further, the reversing mechanism includes a hydraulic rod and an extension rod, the outer wall of the hydraulic rod is fixedly connected with the outer wall of the heat recovery tank, the output end of the hydraulic rod penetrates the outer wall of the heat recovery tank and is fixedly connected with one end of the extension rod, the other end of the extension rod is connected with the mobile assembly.

[0008] Further, the mobile assembly includes a hose and a connecting ring, the outer wall of the upper end of the hose is fixedly connected with the inner wall of the inlet and outlet air pipe located above the heat recovery tank, the outer wall of the lower end of the hose is fixedly connected with the inner wall of the connecting ring, the side wall of the connecting ring is fixedly connected with the end of the extension rod away from the hydraulic rod, and the hose and the connecting ring are located above the partition plate.

[0009] Further, the upper end of the partition plate is fixedly connected with a baffle, the side wall of the baffle is fixedly connected with the inner wall of the heat recovery tank, two air inlet openings are formed through the upper surface of the baffle, the two air inlet openings are respectively matched with the two filter mouths and are aligned, the bottom surface of the connecting ring is slidingly connected with the upper surface of the baffle, and the hose is in communication with the air inlet opening.

[0010] Further, the upper surface of the baffle is provided with a sliding groove in communication with the two air inlet openings, and the inner wall of the sliding groove is slidingly connected with the outer wall of the connecting ring.

[0011] Further, the filter assembly includes a detachable assembly, a filter screen and two side plates, the two sides of the filter screen are respectively fixedly connected with the upper ends of the two side plates, the bottom surfaces of the two side plates are slidingly connected with the upper surface of the support plate, one end of the filter screen and the two side plates is connected with the detachable assembly, the other end of the detachable assembly penetrates the inner wall of the heat recovery tank to the outside of the heat recovery tank, and the cleaning mechanism abuts against the upper surface of the filter screen.

[0012] Furthermore, the detachable assembly includes a mounting plate, a sealing plate, and several mounting blocks. One side of the sealing plate is fixedly connected to the filter screen and one end of the two side plates. The other side of the sealing plate extends through the inner wall of the heat recovery box to the outside of the heat recovery box and is fixedly connected to one side of the mounting plate. The surface of the mounting plate is fixedly connected to several mounting blocks, and each mounting block is provided with bolts for fastening to the heat recovery box.

[0013] Furthermore, a push plate is fixedly connected to the side of the side plate away from the sealing plate. The bottom surface of the push plate abuts against the upper surface of the support plate, and the upper end of the push plate is sloped on the side near the sealing plate.

[0014] Furthermore, the cleaning mechanism includes a second hydraulic rod and a cleaning brush. The outer wall of the second hydraulic rod is fixedly connected to the side wall of the heat recovery box, and the output end of the second hydraulic rod passes through the outer wall of the heat recovery box and is fixedly connected to the cleaning brush. The cleaning surface of the cleaning brush abuts against the surface of the filter screen.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. This type of waste heat recovery energy-saving device for industrial boilers, by setting a partition plate and a support plate between the two inlet and outlet pipes of the heat recovery box, and setting two filter components inside the support plate, can filter impurities in the exhaust gas when the exhaust gas is introduced into the heat recovery box, thereby filtering out larger impurities in the exhaust gas, reducing the impact on the water pipes, and improving heat exchange time and heat exchange efficiency.

[0017] 2. This type of waste heat recovery energy-saving device for industrial boilers, by setting a reversing mechanism and a moving component above the partition plate, and setting a cleaning mechanism on both filter components, and matching and aligning the reversing mechanism with the two filter components respectively, can change the filtration direction as needed during filtration, and wipe and clean the other filter component, thereby improving the overall service life. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall appearance of the present utility model;

[0019] Figure 2 This is a schematic diagram of the overall appearance of the present invention from another perspective;

[0020] Figure 3 This is a schematic diagram of the internal structure of the heat recovery box of this utility model;

[0021] Figure 4 This is a cross-sectional schematic diagram of the heat recovery box of this utility model;

[0022] Figure 5 This is a detailed connection diagram of the reversing mechanism and the moving component of this utility model;

[0023] Figure 6 The detailed connection schematic view of the filter assembly and the cleaning mechanism of the utility model.

[0024] In the figure: 1, heat recovery tank; 2, inlet and outlet air pipe; 3, inlet and outlet water pipe; 4, No. 1 hydraulic rod; 5, No. 2 hydraulic rod; 6, mounting plate; 7, extension rod; 8, hose; 9, connecting ring; 10, cleaning brush; 11, partition plate; 111, sliding groove; 112, air inlet; 12, support plate; 121, filter port; 13, partition plate; 14, sealing plate; 15, mounting block; 16, side plate; 17, push plate; 18, filter screen. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments.

[0026] Please refer to Figures 1-5 A waste heat recovery energy-saving device for industrial boiler, including heat recovery tank 1, install two inlet and outlet air pipes 2 on the upper and lower ends of heat recovery tank 1 and install two inlet and outlet water pipes 3 on the front and rear sides of heat recovery tank 1, one side of heat recovery tank 1 is connected with a reversing mechanism, the output end of the reversing mechanism penetrates the outer wall of heat recovery tank 1 and is connected with a moving assembly, the lower end of the moving assembly faces the inside of heat recovery tank 1, the upper end of the moving assembly is connected with the inlet and outlet air pipe 2 located above heat recovery tank 1, the inner wall of the upper end of heat recovery tank 1 is fixedly connected with a support plate 12, the upper surface of the middle part of support plate 12 is fixedly connected with a partition plate 13, the moving assembly is located above partition plate 13, filter ports 121 are formed through the two sides of support plate 12, the upper surface of support plate 12 is connected with two filter assemblies, the two filter assemblies are matched and aligned with the two filter ports 121 respectively, cleaning mechanisms are connected with the two sides of heat recovery tank 1, one end of the two cleaning mechanisms adjacent to each other is located inside heat recovery tank 1, and the two cleaning mechanisms are matched and aligned with the two filter assemblies respectively.

[0027] The waste heat recovery energy-saving device for industrial boiler in the utility model is similar in structure to the existing boiler waste heat recovery device, such as the boiler waste heat recovery device disclosed in the patent with publication number CN221349792U. For example Figures 1-5As shown, the waste heat recovery energy-saving device for industrial boiler in the utility model, first of all, the two inlet and outlet air pipes 2 on the upper and lower ends of the heat recovery tank 1 are connected with the air outlet end of the boiler and the subsequent equipment (such as a spray tower or other filtering device), then the two inlet and outlet water pipes 3 are connected with the inlet and outlet ends of the external preheating water tank, then the exhaust gas of the boiler combustion enters the heat recovery tank 1 through the inlet and outlet air pipes 2, at the same time, the water in the preheating water tank is also transported to the heat recovery tank 1 to realize heat exchange with the exhaust gas.

[0028] When the exhaust gas enters the heat recovery tank 1, it is connected with a group of filtering components on one side of the partition plate 13 through the moving assembly, then the filtering components can block and filter the larger impurities in the exhaust gas, and then the filtered hot air enters the heat recovery tank 1 after passing through the filtering components and exchanges heat with the circulating water pipe.

[0029] After the exhaust gas contacts the filtering components for a period of time, the first filtering component will be blocked because too many impurities are blocked, at this time, the reversing mechanism is started, the moving assembly is moved from one side of the partition plate 13 to the other side through the reversing mechanism, so that the exhaust gas can be filtered from the inside of the filtering component on the other side.

[0030] When the exhaust gas flows through the second filtering component, the cleaning mechanism matched with the first filtering component is opened at this time, the cleaning mechanism starts to wipe the surface of the filtering component, so that the impurities accumulated and blocked on the surface of the filtering component can be pushed to both sides for temporary collection, then when the second filtering component is blocked, the moving assembly can be moved back to the position of the first filtering component through the reversing mechanism again, which is convenient and fast.

[0031] After switching between the two filtering components for several times, the cleaning effect of the cleaning component may not be good enough, or the regular maintenance of the boiler is reached, at this time, the filtering component can be cleaned or replaced; through the above-mentioned manner, the larger impurities contained in the exhaust gas of the boiler can be filtered out when heat exchange is performed, so as to reduce the influence on the water pipe, thereby improving the heat exchange time and heat exchange efficiency.

[0032] It should be particularly noted that the external boiler and the preheating water tank are existing mature technologies, so they are not described in detail here.

[0033] As shown in Figure 3 and Figure 5 The reversing mechanism includes a hydraulic rod 4 and an extension rod 7, the outer wall of the hydraulic rod 4 is fixedly connected with the outer wall of the heat recovery tank 1, the output end of the hydraulic rod 4 penetrates the outer wall of the heat recovery tank 1 and is fixedly connected with one end of the extension rod 7, and the other end of the extension rod 7 is connected with the moving assembly.

[0034] More specifically, when the mobile assembly needs to be controlled to reverse between the two partition plates 13, only the first hydraulic rod 4 needs to be turned on. After the first hydraulic rod 4 is started, the output end controls the extension rod 7 to move, and then the extension rod 7 and the mobile assembly can move back and forth during the movement of the output end of the first hydraulic rod 4.

[0035] As shown in Figure 3 and Figure 5 , the mobile assembly includes a hose 8 and a connecting ring 9. The outer wall of the upper end of the hose 8 is fixedly connected to the inner wall of the inlet and outlet air pipe 2 located above the heat recovery box 1. The outer wall of the lower end of the hose 8 is fixedly connected to the inner wall of the connecting ring 9. The side wall of the connecting ring 9 is fixedly connected to the end of the extension rod 7 away from the first extension rod 7. The hose 8 and the connecting ring 9 are located above the partition plate 13.

[0036] More specifically, when the extension rod 7 moves, it will pull the connecting ring 9 to move together. Because the upper end of the hose 8 is always connected to the inside of the inlet and outlet air pipe 2, the gas entering from the inside of the inlet and outlet air pipe 2 will blow along the connecting ring 9 to the corresponding first filter assembly or second filter assembly.

[0037] As shown in Figure 4 , the upper end of the partition plate 13 is fixedly connected with a partition plate 11. The side wall of the partition plate 11 is fixedly connected to the inner wall of the heat recovery box 1. Two air inlets 112 are provided on the upper surface of the partition plate 11. The two air inlets 112 are respectively matched and aligned with two filter ports 121. The bottom surface of the connecting ring 9 is slidingly connected to the upper surface of the partition plate 11. The hose 8 is in communication with the inside of the air inlet 112. The upper surface of the partition plate 11 is provided with a sliding groove 111 in communication with the two air inlets 112. The inner wall of the sliding groove 111 is slidingly connected to the outer wall of the connecting ring 9.

[0038] More specifically, by providing the partition plate 11, the area of the two filter assemblies can be separated into two spaces that are not connected above, and at the same time, the gas outlet end of the connecting ring 9 can be more accurately sprayed from the air inlet 112 to the surface of the filter assembly, without affecting the other filter assembly.

[0039] By providing the sliding groove 111, a sliding track can be provided for the connecting ring 9, and at the same time, the sealing performance of the connecting ring 9 during movement can be improved.

[0040] As shown in Figure 6 , the filter assembly includes a detachable assembly, a filter screen 18, and two side plates 16. The two sides of the filter screen 18 are respectively fixedly connected to the upper ends of the two side plates 16. The bottom surfaces of the two side plates 16 are slidingly connected to the upper surface of the support plate 12. One end of the filter screen 18 and the two side plates 16 is connected to the detachable assembly. The other end of the detachable assembly penetrates through the inner wall of the heat recovery box 1 to the outside of the heat recovery box 1. The cleaning mechanism abuts against the upper surface of the filter screen 18.

[0041] More specifically, during normal use, the exhaust gas blown in the hose 8 will be directly blown to the surface of the filter screen 18 after passing through the air inlet 112, and then the larger impurities in the exhaust gas will be filtered by the filter screen 18, so as to reduce the speed of impurities polluting the water pipe, thereby increasing the service life of the water pipe inside the heat recovery tank 1.

[0042] After the cleaning mechanism is started, the cleaning mechanism moves forward and backward, and pushes the accumulated impurities clogging the surface of the filter screen 18 to the space between the two side plates 16 and the support plate 12 for temporary storage; when the boiler or the heat recovery tank 1 is overhauled and cleaned, the filter screen 18 and the side plate 16 can be easily and conveniently extracted from one side of the heat recovery tank 1 through the detachable assembly.

[0043] As shown in Figure 6 , the detachable assembly comprises a mounting plate 6, a sealing plate 14 and a plurality of mounting blocks 15, one side of the sealing plate 14 is fixedly connected with the filter screen 18 and one end of the two side plates 16, the other side of the sealing plate 14 penetrates the inner wall of the heat recovery tank 1 to the outside of the heat recovery tank 1 and is fixedly connected with one side of the mounting plate 6, the surface of the mounting plate 6 is fixedly connected with the plurality of mounting blocks 15, and the plurality of mounting blocks 15 are fastened to the heat recovery tank 1 by bolts.

[0044] More specifically, during normal filtration, the sealing plate 14 seals the opening of the heat recovery tank 1, so that the exhaust gas cannot leak from the opening, and then the mounting plate 6 is fixed to the surface of the heat recovery tank 1 by bolts penetrating the mounting blocks 15, thereby increasing the stability of the whole.

[0045] When the filter screen 18 needs to be cleaned and replaced, the bolts are loosened, and then the sealing plate 14, the filter screen 18 and the side plate 16 can be extracted from the inside of the heat recovery tank 1 through the handle on the mounting plate 6.

[0046] As shown in Figure 6 , the side plate 16 is fixedly connected with a push plate 17 on the side away from the sealing plate 14, the bottom surface of the push plate 17 abuts against the upper surface of the support plate 12, and the side of the upper end of the push plate 17 close to the sealing plate 14 is inclined.

[0047] More specifically, by arranging the push plate 17, the accumulated impurities between the side plate 16 and the support plate 12 can be taken out together when the side plate 16 is extracted, which is convenient for cleaning. By arranging the upper end of the push plate 17 as an inclined surface, the impurities can be collected to a greater extent when the cleaning mechanism cleans the surface of the filter screen 18.

[0048] As shown in Figure 3 and Figure 6As shown, the cleaning mechanism comprises the second hydraulic rod 5 and the cleaning brush 10, the outer wall of the second hydraulic rod 5 is fixedly connected with the side wall of the heat recovery box 1, the output end of the second hydraulic rod 5 penetrates the outer wall of the heat recovery box 1 and is fixedly connected with the cleaning brush 10, and the cleaning surface of the cleaning brush 10 abuts against the upper surface of the filter screen 18.

[0049] More specifically, when the surface of the filter screen 18 needs to be cleaned, the second hydraulic rod 5 is only needed to be turned on, and then the output end of the second hydraulic rod 5 can move back and forth on the surface of the filter screen 18 with the cleaning brush 10, so that the sundries accumulated on the surface of the filter screen 18 can be scraped to the space between the side plate 16 and the supporting plate 12.

[0050] Although the embodiments of the present application have been shown and described, it should be understood by those ordinary skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A waste heat recovery energy saving device for industrial boilers, comprising a heat recovery tank (1), two air inlet and outlet pipes (2) installed on the upper and lower ends of the heat recovery tank (1), and two water inlet and outlet pipes (3) installed on the front and rear sides of the heat recovery tank (1), characterized in that: One side of the heat recovery tank (1) is connected with a reversing mechanism, the output end of the reversing mechanism penetrates the outer wall of the heat recovery tank (1) and is connected with a moving assembly, the lower end of the moving assembly faces the inside of the heat recovery tank (1), the upper end of the moving assembly is connected with the air inlet and outlet pipe (2) above the heat recovery tank (1), the inner wall of the upper end of the heat recovery tank (1) is fixedly connected with a supporting plate (12), the upper surface of the middle part of the supporting plate (12) is fixedly connected with a partition plate (13), the moving assembly is located above the partition plate (13), the supporting plate (12) is provided with a filtering opening (121) penetratingly formed on both sides of the partition plate (13), the upper surface of the supporting plate (12) is connected with two filtering assemblies, the two filtering assemblies are respectively matched and aligned with the two filtering openings (121), both sides of the heat recovery tank (1) are connected with cleaning mechanisms, one end of the two cleaning mechanisms adjacent to each other is located inside the heat recovery tank (1), and the two cleaning mechanisms are respectively matched and aligned with the two filtering assemblies.

2. A waste heat recovery and energy saving device for industrial boilers as claimed in claim 1 wherein: The reversing mechanism comprises a No. 1 hydraulic rod (4) and an extension rod (7), the outer wall of the No. 1 hydraulic rod (4) is fixedly connected with the outer wall of the heat recovery tank (1), the output end of the No. 1 hydraulic rod (4) penetrates the outer wall of the heat recovery tank (1) and is fixedly connected with one end of the extension rod (7), and the other end of the extension rod (7) is connected with the moving assembly.

3. A waste heat recovery and energy saving device for industrial boilers as claimed in claim 2 wherein: The moving assembly comprises a hose (8) and a connecting ring (9), the outer wall of the upper end of the hose (8) is fixedly connected with the inner wall of the air inlet and outlet pipe (2) above the heat recovery tank (1), the outer wall of the lower end of the hose (8) is fixedly connected with the inner wall of the connecting ring (9), the side wall of the connecting ring (9) is fixedly connected with the end of the extension rod (7) away from the No. 1 extension rod (7), and the hose (8) and the connecting ring (9) are located above the partition plate (13).

4. A waste heat recovery and energy saving device for industrial boilers as claimed in claim 3 wherein: The upper end of the partition plate (13) is fixedly connected with a partition plate (11), the side wall of the partition plate (11) is fixedly connected with the inner wall of the heat recovery tank (1), the upper surface of the partition plate (11) is provided with two air inlet openings (112) penetratingly formed, the two air inlet openings (112) are respectively matched and aligned with the two filtering openings (121), the bottom surface of the connecting ring (9) is slidably connected with the upper surface of the partition plate (11), and the hose (8) is in communication with the inside of the air inlet opening (112).

5. A waste heat recovery and energy saving device for industrial boilers as claimed in claim 4 wherein: The upper surface of the partition plate (11) is provided with a sliding groove (111) in communication with the two air inlet openings (112), and the inner wall of the sliding groove (111) is slidably connected with the outer wall of the connecting ring (9).

6. A waste heat recovery and energy saving device for industrial boilers as claimed in claim 1 wherein: The filtering assembly comprises a detachable assembly, a filter screen (18) and two side plates (16), the two sides of the filter screen (18) are respectively fixedly connected with the upper ends of the two side plates (16), the bottom surfaces of the two side plates (16) are slidably connected with the upper surface of the supporting plate (12), one end of the filter screen (18) and the two side plates (16) is connected with the detachable assembly, the other end of the detachable assembly penetrates the inner wall of the heat recovery tank (1) to the outside of the heat recovery tank (1), and the cleaning mechanism abuts against the upper surface of the filter screen (18).

7. A waste heat recovery and energy saving device for industrial boilers as claimed in claim 6 wherein: The detachable assembly comprises a mounting plate (6), a sealing plate (14) and a plurality of mounting blocks (15), one side of the sealing plate (14) is fixedly connected with a filter screen (18) and one end of two side plates (16), the other side of the sealing plate (14) penetrates through the inner wall of the heat recovery box (1) to the outside of the heat recovery box (1) and is fixedly connected with one side of the mounting plate (6), the surface of the mounting plate (6) is fixedly connected with the plurality of mounting blocks (15), and the plurality of mounting blocks (15) are all provided with bolts for fastening connection with the heat recovery box (1).

8. A waste heat recovery and energy saving device for industrial boilers as claimed in claim 7 wherein: The side plate (16) is fixedly connected with a push plate (17) away from the sealing plate (14), the bottom surface of the push plate (17) abuts against the upper surface of the supporting plate (12), and the side, close to the sealing plate (14), of the upper end of the push plate (17) is provided in a slope.

9. A waste heat recovery and energy saving device for industrial boilers as claimed in claim 6 wherein: The cleaning mechanism comprises a No. 2 hydraulic rod (5) and a cleaning brush (10), the outer wall of the No. 2 hydraulic rod (5) is fixedly connected with the side wall of the heat recovery box (1), the output end of the No. 2 hydraulic rod (5) penetrates through the outer wall of the heat recovery box (1) and is fixedly connected with the cleaning brush (10), and the cleaning surface of the cleaning brush (10) abuts against the upper surface of the filter screen (18).

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