Coal mine goaf gas drainage device

Abstract

The invention belongs to the technical field of coal mine gas extraction, and particularly relates to a coal mine goaf gas drainage device. Comprising an exhaust pipe, a water inlet pipe, a water outlet pipe, a collecting pipe, an exhaust pump and a cyclone separator, one end of an air inlet of the exhaust pipe is connected with a coal briquette crushing assembly, one end of an air outlet of the exhaust pipe is connected with a cyclone separator through an air pump, a water inlet pipe is fixedly connected below the exhaust pipe, and a coal cinder filtering assembly is arranged in the water inlet pipe; the exhaust pipe is connected with a helium adjusting assembly; by means of coal briquette chopping and coal cinder filtering treatment, the coal cinder can be prevented from influencing the gas extraction efficiency, meanwhile, by installing a helium adjusting device, quantitative helium is released while gas is extracted, pressure distribution in a goaf is kept, and the risk of coal mine collapse is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine gas extraction, and in particular relates to a coal mine goaf gas extraction device. Background Art

[0002] Coal mine goaf is the hole or cavity left after underground coal or gangue is mined during coal mining. In the process of coal mining, it is necessary to open a tunnel from the underground coal location to the coal mine wellhead to transport the ore and coal encountered during the mining process to the ground. As coal and other ores are continuously transported out, coal goaf is formed underground. In the process of coal formation, a large amount of gas will be absorbed in the coal seam. When the coal is mined, the gas in the coal seam will gradually be released, and part of the gas will accumulate in the goaf. The gas itself is non-toxic, but it cannot be breathed by people. When the gas concentration in the goaf is too high, it will reduce the oxygen content in the air and cause people to suffocate to death. Therefore, a coal mine goaf gas extraction device is needed to reduce the gas concentration.

[0003] When the existing coal mine goaf gas extraction device is extracting gas, the gas carrying coal blocks will block the air inlet of the extraction device, and the inhaled coal ash will gradually deposit inside the pipeline, blocking the pipeline, affecting the gas extraction efficiency. At the same time, during the extraction process, the accumulated water in the goaf will also be sucked into the extraction pipeline, which will increase the gas humidity and affect the subsequent transportation and combustion of the gas. In addition, when the gas is extracted, the pressure distribution in the goaf changes, and part of the supporting force originally provided by the gas pressure disappears, which will change the stress state of the surrounding coal and rock mass, making coal mine collapse more likely to occur.

[0004] Therefore, it is necessary to provide a new coal mine goaf gas extraction device to solve the above technical problems. Summary of the invention

[0005] The present invention overcomes the shortcomings of the prior art and proposes a gas extraction device for coal mine goaf. The present invention is achieved through the following technical solutions: A gas extraction device for coal mine goaf, comprising an air extraction pipe, a water inlet pipe, a water outlet pipe, a collecting pipe, an air extraction pump and a cyclone separator; one end of the air inlet of the air extraction pipe is connected to a coal block crushing assembly, one end of the air outlet of the air extraction pipe is connected to a cyclone separator through an air extraction pump, and the air outlet of the cyclone separator is fixedly connected to the collecting pipe; a water inlet pipe is fixedly connected below the air extraction pipe, and a water outlet pipe is fixedly connected to the bottom of the water inlet pipe; a coal slag filtering assembly is arranged inside the water inlet pipe; the air extraction pipe is connected to a helium regulating assembly; The coal crushing assembly includes a second rotating shaft, cutting blades and a fixed box; the fixed box is fixedly connected inside the exhaust pipe, and the second rotating shaft is rotatably connected to one side of the fixed box close to the air inlet of the exhaust pipe, and the second rotating shaft is fixedly connected to a plurality of cutting blades; The helium regulating assembly comprises a fixed tube, a turntable, a fixed column, a first movable plate, a second movable plate and a piston; a fixed tube is fixedly connected to the top of the exhaust tube, and a helium outlet pipe is fixedly connected to the top of the fixed tube; a turntable is fixedly connected to the end of the second rotating shaft away from the cutting fan blade, the turntable is located in the fixed box, a fixed column is fixedly connected to one side of the turntable, a first movable plate is rotatably connected to the fixed column, a second movable plate is rotatably connected to the top of the first movable plate, a piston is rotatably connected to the top of the second movable plate, the piston is slidably connected inside the fixed tube, a first one-way valve is arranged above the fixed tube, a helium box is fixedly connected to the top of the exhaust tube, a helium tube is fixedly connected to the air outlet of the helium box, the helium tube is fixedly connected to the top of the fixed tube, and a second one-way valve is arranged on the helium tube.

[0006] Furthermore, a first coal ash outlet is arranged at the bottom of the cyclone separator.

[0007] Furthermore, the top of the water outlet pipe is connected to the collecting pipe through a residual gas inlet pipe.

[0008] Furthermore, the coal slag filtering assembly includes a filter plate, a reciprocating screw and a movable plate; the filter plate is fixedly connected to the upper part of the water inlet pipe, the reciprocating screw is rotatably connected to the upper part of the water inlet pipe, the movable plate is cooperatively connected to the reciprocating screw, and a number of cleaning brushes are arranged below the movable plate, and the cleaning brushes are in contact with the upper surface of the filter plate; the reciprocating screw is connected to a driving mechanism; a second coal slag outlet is arranged above the water inlet pipe, and the height of the second coal slag outlet and the filter plate are matched to discharge the coal slag on the filter plate.

[0009] Furthermore, the driving mechanism includes a first rotating shaft and a belt transmission assembly; the first rotating shaft is rotatably connected below the water inlet pipe, and one end of the first rotating shaft located inside the water inlet pipe is circumferentially fixedly connected to a plurality of support plates, and a power box is fixedly connected to the support plate; the first rotating shaft and the reciprocating screw are connected via a belt transmission assembly.

[0010] Furthermore, the belt drive assembly includes a main pulley, a transmission belt and a secondary pulley; the first rotating shaft is located at one end outside the water inlet pipe and is fixedly connected to the main pulley, the main pulley is connected to the secondary pulley through the transmission belt, and a reciprocating screw is fixedly connected in the middle of the secondary pulley.

[0011] Furthermore, a protection box is fixedly connected to the outer wall of the water inlet pipe, and the main pulley, transmission belt and auxiliary pulley are all arranged in the protection box. The main pulley is rotatably connected to the lower part of the protection box, and the auxiliary pulley is rotatably connected to the upper part of the protection box.

[0012] Furthermore, the second coal ash outlet is located on a side away from the connection point between the reciprocating screw and the water inlet pipe, and the connection point between the second coal ash outlet and the water inlet pipe is located at the filter plate or below the filter plate. The coal ash on the filter plate screen can be pushed into the second coal ash outlet for discharge by moving the plate.

[0013] Furthermore, the diameter of the water outlet pipe is larger than the diameters of the air extraction pipe, the water inlet pipe and the collecting pipe.

[0014] The beneficial effects of the present invention compared with the prior art are as follows: 1. The present invention provides a gas extraction device for coal mine goaf. By installing a coal block crushing and coal slag filtering device, the water and coal slag brought in when extracting gas are processed to prevent the coal slag from affecting the gas extraction efficiency and prevent the gas humidity from increasing, thereby affecting the subsequent transportation and combustion of the gas.

[0015] 2. The present invention provides a gas extraction device for coal mine goaf. By installing a helium regulating component, a certain amount of helium is released while the gas is extracted, so that the pressure distribution in the goaf will not change too much, reducing the risk of coal mine collapse. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The overall structural diagram of the coal mine goaf gas extraction device provided by the present invention; Figure 2 It is a structural schematic diagram of the coal slag filtering assembly of the present invention; Figure 3 It is a structural schematic diagram of the belt transmission assembly of the present invention; Figure 4 It is a structural schematic diagram of the coal block crushing assembly of the present invention; Figure 5 It is a schematic structural diagram of the helium regulating assembly described in the present invention.

[0017] Numbers in the figure: 1. exhaust pipe; 2. water inlet pipe; 3. water outlet pipe; 4. residual air inlet pipe; 5. collecting pipe; 6. exhaust pump; 7. cyclone separator; 8. first coal slag outlet; 9. fixed pipe; 10. helium outlet pipe; 11. helium box; 12. protection box; 13. second coal slag outlet; 14. first rotating shaft; 15. main pulley; 16. transmission belt; 17. secondary pulley; 18. reciprocating screw; 19. moving plate; 20. filter plate; 21. support plate; 22. power box; 23. second rotating shaft; 24. cutting fan blade; 25. fixed box; 26. helium pipe; 27. first one-way valve; 28. second one-way valve; 29. ​​turntable; 30. fixed column; 31. first movable plate; 32. second movable plate; 33. piston. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail in conjunction with the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The technical solutions of the present invention are described in detail below in conjunction with the embodiments and the accompanying drawings, but the scope of protection is not limited thereto.

[0019] See also Figures 1 to 5 The present embodiment proposes a gas extraction device for coal mine goaf, which comprises an exhaust pipe 1, a water inlet pipe 2, a water outlet pipe 3, a residual gas inlet pipe 4, a collecting pipe 5, an exhaust pump 6 and a cyclone separator 7; one end of the exhaust port of the exhaust pipe 1 is connected with a coal block crushing assembly, one end of the exhaust port of the exhaust pipe 1 is connected with the cyclone separator 7 through the exhaust pump 6, and the exhaust port of the cyclone separator 7 is fixedly connected with the collecting pipe 5; a first coal slag outlet 8 is provided at the bottom of the cyclone separator 7 for discharging impurities such as coal slag separated by the cyclone separator 7; a water inlet pipe 2 is fixedly connected at the bottom of the exhaust pipe 1, a water outlet pipe 3 is fixedly connected at the bottom of the water inlet pipe 2, and the top of the water outlet pipe 3 is connected with the collecting pipe 5 through the residual gas inlet pipe 4; The gas is sucked into the exhaust pipe 1 from one end of the air inlet of the exhaust pipe 1 through the exhaust pump 6. When the gas carrying coal blocks passes through the coal block crushing component, the coal blocks are crushed to prevent the exhaust pipe 1 from being blocked; the water and coal slag carried in the gas enter the water inlet pipe 2 after passing through the water inlet pipe 2. A coal slag filtering component is arranged inside the water inlet pipe 2. The coal slag in the water is filtered by the coal slag filtering component and discharged from the water inlet pipe 2, and the water flows into the water outlet pipe 3 and is discharged through the water outlet pipe 3; the gas remaining in the water outlet pipe 3 enters the collecting pipe 5 through the residual gas inlet pipe 4; the gas that has been blocked in the exhaust pipe 1 and has been freed of some coal slag and water enters the cyclone separator 7 to further remove the residual coal slag, and finally the treated gas enters the collecting pipe 5.

[0020] Specifically, the coal block crushing assembly includes a second rotating shaft 23, cutting blades 24 and a fixed box 25; the fixed box 25 is fixedly connected to the inside of the exhaust pipe 1, and the fixed box 25 is rotatably connected to the second rotating shaft 23 on one side close to the air inlet of the exhaust pipe 1, and the second rotating shaft 23 is fixedly connected to a plurality of cutting blades 24; the vacuum pump 6 generates negative pressure when it works, and the gas in the goaf is sucked into the device through the exhaust pipe 1, and the gas entering the exhaust pipe 1 encounters the cutting blades 24. Since the cutting blades 24 are similar to the blades of wind power generation, the cutting blades 24 rotate to perform preliminary processing on the gas, and the coal blocks carried by the gas when entering are chopped into coal slag to prevent the coal blocks from blocking the air inlet and affecting the use of the device. Subsequently, the coal slag will enter the water inlet pipe 2 and the cyclone separator 7 along with the gas and the sucked water for further separation and processing. Most of the gas that has undergone preliminary treatment enters the cyclone separator 7. The cyclone separator 7 uses the principle of centrifugal force. When the gas containing gas runs in a spiral shape in the cyclone separator 7, the coal slag is thrown to the periphery due to the centrifugal force, loses inertia after touching the cylinder wall, and falls along the cylinder wall under the action of gravity. The separated coal slag is discharged through the first coal slag outlet 8 at the bottom of the cyclone separator 7, while the relatively clean gas with most of the impurities removed forms a vortex and is discharged through the collection pipe 5.

[0021] The cinder filter assembly arranged inside the water inlet pipe 2 includes a filter plate 20, a reciprocating screw 18, a movable plate 19 and a first rotating shaft 14; the filter plate 20 is fixedly connected to the upper part of the water inlet pipe 2, and the reciprocating screw 18 is rotatably connected to the upper part of the water inlet pipe 2, and the movable plate 19 is matched with the reciprocating screw 18, and a plurality of cleaning brushes are arranged below the movable plate 19, and the cleaning brushes are in contact with the upper surface of the filter plate 20; the first rotating shaft 14 is rotatably connected to the lower part of the water inlet pipe 2, and a plurality of support plates 21 are fixedly connected to the circumference of one end of the first rotating shaft 14 located inside the water inlet pipe 2, and a power box 22 is fixedly connected to the support plate 21; the first rotating shaft 14 is rotatably connected to the upper part of the water inlet pipe 2, and the power box 22 is fixedly connected to the support plate 21; the first rotating shaft 14 is connected to the reciprocating screw 18, and the movable plate 19 is matched with the reciprocating screw 18, and a plurality of cleaning brushes are arranged below the movable plate 19, and the cleaning brushes are in contact with the upper surface of the filter plate 20; the first rotating shaft 14 is rotatably connected to the lower part of the water inlet pipe 2, and a plurality of support plates 21 are fixedly connected to the circumference of one end of the first rotating shaft 14 located inside the water inlet pipe 2, and a power box 22 is fixedly connected to the support plate 21; the first rotating shaft 14 is connected to the reciprocating screw 18, and the movable plate 19 is matched with the reciprocating screw 18, and the movable plate 19 is matched with the reciprocating screw 18, and the movable The multiple thread rods 18 are connected by a belt transmission assembly; the belt transmission assembly includes a main pulley 15, a transmission belt 16 and a secondary pulley 17; the first rotating shaft 14 is fixedly connected to a main pulley 15 at one end located outside the water inlet pipe 2, the main pulley 15 is connected to a secondary pulley 17 through a transmission belt 16, and a reciprocating thread rod 18 is fixedly connected in the middle of the secondary pulley 17; the outer wall of the water inlet pipe 2 is fixedly connected to a protection box 12, the main pulley 15, the transmission belt 16 and the secondary pulley 17 are all arranged in the protection box 12, the main pulley 15 is rotatably connected to the lower part of the protection box 12, and the secondary pulley 17 is rotatably connected to the upper part of the protection box 12. A second cinder outlet 13 is provided above the water inlet pipe 2. The second cinder outlet 13 is located on a side away from the connection point between the reciprocating screw 18 and the water inlet pipe 2. The connection point between the second cinder outlet 13 and the water inlet pipe 2 is located at the filter plate 20 or slightly below the filter plate 20. The cinders on the filter plate 20 can be pushed into the second cinder outlet 13 for discharge through the movable plate 19. The diameter of the second cinder outlet 13 can be adapted to the diameter of the filter plate 20 or slightly larger than the diameter of the filter plate 20, so that more cinders on the filter plate 20 can be discharged from the second cinder outlet 13. The coal slag can be filtered through the filter plate 20 to prevent the coal slag from entering the subsequent pipeline or affecting the normal operation of other components. The water passes through the power box 22, converting the potential energy of the water into kinetic energy, so that the first rotating shaft 14 rotates, driving the main pulley 15 to rotate, the main pulley 15 drives the secondary pulley 17 to rotate through the transmission belt 16, and the secondary pulley 17 drives the reciprocating screw 18 to rotate, so that the cleaning brush under the movable plate 19 moves on the surface of the filter plate 20, cleaning the surface of the filter plate 20 and pushing the coal slag into the second coal slag outlet 13, preventing the coal slag from entering the subsequent pipeline or affecting the normal operation of other components. Since the water outlet pipe 3 is thicker than the diameter of other pipes, the water passing through the coal slag filter assembly can enter the water outlet pipe 3 for temporary storage, and the remaining gas enters the collection pipe 5 through the residual gas inlet pipe 4. After the gas is extracted, the water is discharged through the water outlet pipe 3.

[0022] In order to prevent the problem of gas pressure imbalance caused by gas extraction in the goaf, the coal crushing assembly is also connected to a helium regulating assembly. The coal crushing assembly and the helium regulating assembly are linked so that the helium regulating assembly can release helium into the goaf during the operation of the coal crushing assembly. Specifically, the helium regulating assembly includes a fixed pipe 9, a turntable 29, a fixed column 30, a first movable plate 31, a second movable plate 32 and a piston 33; the top of the exhaust pipe 1 is fixedly connected to a fixed pipe 9, the fixed pipe 9 is located above the fixed box 25, and the top of the fixed pipe 9 is fixedly connected to a helium outlet pipe 10; the second rotating shaft 23 is away from the cutting blades 24. A turntable 29 is fixedly connected to one end, and the turntable 29 is located in the fixed box 25. A fixed column 30 is fixedly connected to one side of the turntable 29. A first movable plate 31 is rotatably connected to the fixed column 30. A second movable plate 32 is rotatably connected to the top of the first movable plate 31. A piston 33 is rotatably connected to the top of the second movable plate 32. The piston 33 is slidably connected inside the fixed tube 9. A first one-way valve 27 is arranged above the fixed tube 9. A helium box 11 is fixedly connected to the top of the exhaust pipe 1. A helium tube 26 is fixedly connected to the air outlet of the helium box 11. The helium tube 26 is fixedly connected to the top of the fixed tube 9. A second one-way valve 28 is arranged on the helium tube 26. The rotation of the cutting blades 24 drives the second rotating shaft 23 to rotate, and the second rotating shaft 23 drives the turntable 29 at the right end to rotate. The fixed column 30, the first movable plate 31, the second movable plate 32 and other mechanisms on the turntable 29 are linked to make the piston 33 reciprocate up and down in the fixed tube 9. The up and down movement of the piston 33 changes the volume and pressure in the fixed tube 9. In conjunction with the first one-way valve 27 above the fixed tube 9, the helium in the fixed tube 9 can be pushed in a specific direction and flow rate, and finally discharged from the helium outlet pipe 10, so that a certain amount of helium is released while extracting gas, so that the gas pressure distribution in the goaf will not change too much, reducing the risk of coal mine collapse.

[0023] The working principle of the coal mine goaf gas extraction device provided by the present invention is as follows: The vacuum pump 6 generates negative pressure when it works, and the gas in the goaf is sucked into the device through the vacuum pipe 1. The gas entering the vacuum pipe 1 encounters the cutting blade 24 on the right side. Since the cutting blade 24 is similar to the blade of wind power generation, the cutting blade 24 is automatically operated to perform preliminary processing on the gas and chop up the coal blocks carried by the gas to prevent the coal blocks from blocking the air inlet and affecting the use of the device. The rotation of the cutting blade 24 drives the rotation of the second rotating shaft 23, and drives the rotation of the turntable 29 at the right end. The fixed column 30, the first movable plate 31, the second movable plate 32 and other mechanisms on the turntable 29 are linked to make the piston 33 move in the fixed pipe. 9 reciprocates up and down, and the up and down movement of the piston 33 changes the volume and pressure in the fixed pipe 9. In cooperation with the first one-way valve 27 above the fixed pipe 9, the helium in the fixed pipe 9 can be pushed in a specific direction and flow rate, and finally discharged from the helium outlet pipe 10, so that a certain amount of helium is released while extracting gas, so that the pressure distribution in the goaf will not change too much, reducing the risk of coal mine collapse, and most of the gas after preliminary treatment enters the cyclone separator 7. The cyclone separator 7 uses the principle of centrifugal force. When the gas containing gas runs in a spiral shape in the cyclone separator 7, the coal slag Due to the centrifugal force, the coal slag is thrown to the periphery, and after touching the cylinder wall, it loses inertia and falls along the cylinder wall under the action of gravity. The separated coal slag is discharged through the first coal slag outlet 8 at the bottom of the cyclone separator 7, and the relatively clean gas with most of the impurities removed forms a vortex and is discharged through the collection pipe 5. The water, part of the coal slag and the gas enter the water inlet pipe 2, and the coal slag is filtered by the filter plate 20 to prevent the coal slag from entering the subsequent pipelines or affecting the normal operation of other components. In addition, the water passes through the power box 22, and the potential energy of the water is converted into kinetic energy, so that the first rotating shaft 14 rotates, driving the main pulley 15 to rotate. The main pulley 15 drives the secondary pulley 17 to rotate through the transmission belt 16, and the secondary pulley 17 drives the reciprocating screw 18 to rotate, so that the cleaning brush under the movable plate 19 moves on the surface of the filter plate 20, cleans the surface of the filter plate 20 and pushes the coal slag into the second coal slag outlet 13 to prevent the coal slag from entering the subsequent pipeline or affecting the normal operation of other components. Water can enter the water outlet pipe 3 for temporary storage to prevent the gas humidity from increasing, thereby affecting the subsequent transportation and combustion of the gas, and the remaining gas enters the collection pipe 5 through the residual gas inlet pipe 4. After the gas is extracted, the water is discharged through the water outlet pipe 3.

[0024] The above content is a further detailed description of the present invention in combination with a specific preferred embodiment. It cannot be determined that the specific embodiments of the present invention are limited to this. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the present invention, which should be regarded as belonging to the present invention and the scope of patent protection determined by the submitted claims.

Claims

1. A gas extraction device for coal mine goaf, characterized in that: The invention comprises an air extraction pipe (1), a water inlet pipe (2), a water outlet pipe (3), a collecting pipe (5), an air extraction pump (6) and a cyclone separator (7); one end of the air inlet of the air extraction pipe (1) is connected to a coal crushing assembly, one end of the air outlet of the air extraction pipe (1) is connected to the cyclone separator (7) via the air extraction pump (6), and the air outlet of the cyclone separator (7) is fixedly connected to the collecting pipe (5); the lower part of the air extraction pipe (1) is fixedly connected to the water inlet pipe (2), and the bottom of the water inlet pipe (2) is fixedly connected to the water outlet pipe (3); a coal slag filtering assembly is arranged inside the water inlet pipe (2); the air extraction pipe (1) is connected to a helium regulating assembly; The coal crushing assembly comprises a second rotating shaft (23), cutting blades (24) and a fixing box (25); the fixing box (25) is fixedly connected inside the exhaust pipe (1); the second rotating shaft (23) is rotatably connected to a side of the fixing box (25) close to the air inlet of the exhaust pipe (1); and the second rotating shaft (23) is fixedly connected to a plurality of cutting blades (24); The helium regulating assembly comprises a fixed tube (9), a rotating disk (29), a fixed column (30), a first movable plate (31), a second movable plate (32) and a piston (33); the top of the exhaust pipe (1) is fixedly connected to the fixed tube (9), and the top of the fixed tube (9) is fixedly connected to the helium outlet pipe (10); the end of the second rotating shaft (23) away from the cutting blade (24) is fixedly connected to the rotating disk (29), the rotating disk (29) is located in the fixed box (25), one side of the rotating disk (29) is fixedly connected to the fixed column (30), and the fixed column (30) is rotatably connected to the first movable plate (31), the second movable plate (32) and the second movable plate (33) are fixedly connected to the first movable plate (31), and the second movable plate (32) is rotatably connected to the first movable plate (33). A movable plate (31), the top of the first movable plate (31) is rotatably connected to a second movable plate (32), the top of the second movable plate (32) is rotatably connected to a piston (33), the piston (33) is slidably connected inside a fixed tube (9), a first one-way valve (27) is arranged above the fixed tube (9), the top of the exhaust tube (1) is fixedly connected to a helium box (11), the outlet of the helium box (11) is fixedly connected to a helium tube (26), the helium tube (26) is fixedly connected to the top of the inside of the fixed tube (9), and a second one-way valve (28) is arranged on the helium tube (26).

2. A coal mine goaf gas extraction device according to claim 1, characterized in that: A first coal slag outlet (8) is provided at the bottom of the cyclone separator (7).

3. A coal mine goaf gas extraction device according to claim 1, characterized in that: The top of the water outlet pipe (3) is connected to the collecting pipe (5) via the residual air inlet pipe (4).

4. A coal mine goaf gas extraction device according to claim 1, characterized in that: The coal slag filtering assembly comprises a filter plate (20), a reciprocating screw (18) and a movable plate (19); the filter plate (20) is fixedly connected to the upper part of the water inlet pipe (2); the reciprocating screw (18) is rotatably connected to the upper part of the water inlet pipe (2); the movable plate (19) is matched with the reciprocating screw (18); a plurality of cleaning brushes are arranged below the movable plate (19); the cleaning brushes are in contact with the upper surface of the filter plate (20); the reciprocating screw (18) is connected to a driving mechanism; a second coal slag outlet (13) is arranged above the water inlet pipe (2); the height of the second coal slag outlet (13) and the filter plate (20) are matched to discharge the coal slag on the filter plate (20) 5. A coal mine goaf gas extraction device according to claim 4, characterized in that: The driving mechanism comprises a first rotating shaft (14) and a belt transmission assembly; the first rotating shaft (14) is rotatably connected below the water inlet pipe (2); one end of the first rotating shaft (14) located inside the water inlet pipe (2) is circumferentially fixedly connected to a plurality of support plates (21); the support plates (21) are fixedly connected to a power box (22); the first rotating shaft (14) and the reciprocating screw rod (18) are connected via the belt transmission assembly.

6. A coal mine goaf gas extraction device according to claim 5, characterized in that: The belt transmission assembly comprises a main pulley (15), a transmission belt (16) and a secondary pulley (17); one end of the first rotating shaft (14) located outside the water inlet pipe (2) is fixedly connected to the main pulley (15), the main pulley (15) is connected to the secondary pulley (17) via the transmission belt (16), and a reciprocating screw rod (18) is fixedly connected in the middle of the secondary pulley (17).

7. A coal mine goaf gas extraction device according to claim 6, characterized in that: The outer wall of the water inlet pipe (2) is fixedly connected to a protection box (12); the main pulley (15), the transmission belt (16) and the auxiliary pulley (17) are all arranged in the protection box (12); the main pulley (15) is rotatably connected to the lower part of the protection box (12); and the auxiliary pulley (17) is rotatably connected to the upper part of the protection box (12).

8. A coal mine goaf gas extraction device according to claim 4, characterized in that: The second coal slag outlet (13) is located on a side away from the connection point between the reciprocating screw (18) and the water inlet pipe (2), and the connection point between the second coal slag outlet (13) and the water inlet pipe (2) is located at the filter plate (20) or below the filter plate (20), and the coal slag on the filter plate (20) can be pushed into the second coal slag outlet (13) for discharge by the movable plate (19).

9. A coal mine goaf gas extraction device according to claim 1, characterized in that: The diameter of the water outlet pipe (3) is larger than the diameters of the air extraction pipe (1), the water inlet pipe (2) and the collecting pipe (5).

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