Dust separation device for coal bed gas extraction

Abstract

The invention discloses a dust separation device for coal bed gas extraction, which belongs to the technical field of coal bed gas development and comprises a primary filtering mechanism for primarily filtering dust in extracted coal bed gas and a frame body. The primary filtering mechanism is provided with a collecting mechanism used for collecting dust obtained after primary filtering and a fine filtering mechanism used for further collecting and filtering tiny dust in coal bed gas. In the primary filtration stage, kinetic energy of coal bed gas is utilized to drive the blowing impeller, drive the scraping rod to rotate, automatically scrape and collect dust on the filter plate and prevent blockage, in the fine filtration stage, part of filtered clean gas is utilized to perform automatic back-blowing dust removal on the dust filter membrane through the closed pipe and the back-blowing pipe, an extra power source is not needed, and the dust removal efficiency is improved. Cleaning is achieved through airflow, the filter element blocking risk is reduced, system pressure drop fluctuation is reduced, and it is guaranteed that coalbed methane extraction can be continuously, stably and efficiently conducted for a long time.

Description

A dust separation device for coalbed methane extraction Technical Field

[0001] This invention relates to the field of coalbed methane development technology, and in particular to a dust separation device for coalbed methane extraction. Background Technology

[0002] Coalbed methane (CBM), as an important unconventional natural gas resource, plays a crucial role in ensuring energy security, reducing greenhouse gas emissions, and preventing coal mine gas accidents through its efficient and clean development. During underground CBM extraction, the extracted gas typically contains a large amount of coal dust, including both larger and fine particles. The presence of this dust presents several significant problems. First, the dust rapidly wears down and clogs subsequent gathering and transmission pipelines, compression equipment, and purification devices such as dehydration and desulfurization systems, severely impacting the stability and lifespan of the system. Second, direct emission or utilization of high-dust-content gas pollutes the environment and may damage downstream gas-using equipment. Furthermore, the accumulation of large amounts of dust within equipment can also pose safety hazards.

[0003] Currently, coalbed methane well sites typically use filtration devices to remove dust from the extracted gas. Common preliminary filtration methods include cyclone separators, screens, or simple filter cartridges, which can remove some larger dust particles, but have limited efficiency in capturing smaller dust particles. While subsequent fine filtration devices offer high filtration accuracy, they suffer from the following technical challenges: filter elements or membranes are easily and rapidly clogged by dust, leading to a sharp increase in airflow resistance, significant negative pressure loss during extraction, and reduced gas production efficiency. This necessitates frequent shutdowns to replace or clean the filter media, resulting in a large maintenance workload and disruption to continuous production. The collection and cleaning of dust after preliminary filtration has a low degree of automation, often relying on manual cleaning at regular intervals, which is labor-intensive and can easily cause secondary dust re-entrainment during cleaning, polluting the operating environment. Backflushing cleaning of fine filtration systems usually requires additional power sources and control valve groups, making the system complex and energy-intensive, limiting its applicability in the limited space and power supply conditions of underground coal mines. Furthermore, the connections between primary and fine filtration, dust collection and transfer processes are often not tight enough, and the overall integration, automation, and reliability of the system need to be improved.

[0004] Therefore, there is an urgent need to develop an integrated coalbed methane development device that can adapt to coalbed methane extraction conditions, achieve continuous automatic dust removal and dust collection, has self-cleaning capabilities, and is easy to maintain, so as to improve dust removal efficiency, ensure long-term stable operation of the extraction system, and reduce maintenance costs. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention adopts the following technical solution: a dust separation device for coalbed methane extraction, comprising a frame, on which a primary filtration mechanism, a fine filtration mechanism, and a collection mechanism are provided. The exhaust outlet of the primary filtration mechanism is connected to the inlet of the fine filtration mechanism, and a collection mechanism is provided below the primary filtration mechanism. The primary filtration mechanism is used to perform preliminary filtration of dust in the extracted coalbed methane, the fine filtration mechanism is used to further collect and filter the fine dust in the coalbed methane, and the collection mechanism is used to collect the dust filtered out by the primary filtration mechanism. The primary filtration mechanism includes a lower plate fixedly installed on the frame. A primary filter box is fixedly installed on the top, and an impeller is rotatably installed inside the primary filter box. Multiple upper scrapers are fixedly installed coaxially on the impeller, and a lower scraper is fixedly installed below the upper scrapers. The outer surface of the upper scrapers is in contact with the inner wall of the primary filter box, and the lower surface of the lower scrapers is in contact with the upper surface of the lower plate. An upper outlet pipe is fixedly installed on the primary filter box, and a connecting pipe is fixedly installed on the upper outlet pipe. The connecting pipe is connected to the input port of the fine filtration mechanism. An inner filter plate is provided at the connection between the upper outlet pipe and the primary filter box. A scraping groove is provided on the lower plate, and an injection pipe is fixedly installed below the lower plate. The injection pipe is connected to the wellhead gas production pipeline.

[0006] Furthermore, the collection mechanism includes two vertical sliding columns slidably mounted on the frame, a top plate fixedly mounted on the vertical sliding columns, a lower support fixedly mounted below the vertical sliding columns, a vertical spring between the top plate and the frame, a discharge groove on the lower support, and a slag hopper fixedly mounted below the lower support, with the discharge groove located above the slag hopper; the collection mechanism also includes a motor frame fixedly mounted on the frame, a motor fixedly mounted on the motor frame, a hexagonal column fixedly mounted on the motor shaft of the motor, a middle column slidably mounted outside the hexagonal column, and an upper... The upper and lower troughs each have six through slots. A collection box is fixedly installed between the through slots of the upper and lower troughs, and the collection box is located below the scraping trough. An upper limit plate is fixedly installed on the intermediate column, an upper bearing is rotatably installed on the intermediate column, and a lower bearing is rotatably installed on the frame. The inner ring of the lower bearing is fixedly installed to the intermediate column, and a tension spring is installed between the lower bearing and the upper bearing. The collection mechanism also includes a push-out electric cylinder fixedly installed on the frame. A push-out block is fixedly installed on the output end of the push-out electric cylinder, and the push-out block is located above the slag hopper.

[0007] Furthermore, the fine filtration mechanism includes an upper plate fixedly mounted on a frame, a sealed shell fixedly mounted on the upper plate, an upper sealing disc fixedly mounted on the upper plate, the upper sealing disc being located inside the sealed shell, three internal air outlet pipes and three sealed pipes fixedly mounted on the upper sealing disc, and a return air pipe fixedly mounted on the upper sealing disc, the return air pipe communicating with the three sealed pipes, and the return air pipe being concentric with the upper sealing disc; a sliding plate slidably mounted inside the upper plate, two dust filter membranes fixedly mounted on the sliding plate, two handles fixedly mounted on the sliding plate, a slot provided on the sliding plate, and two locking pins provided on the upper plate, conventionally... In this state, a locking pin is inserted into the slot of the sliding plate; the fine filtration mechanism also includes a lower shell fixedly installed on the upper side of the frame and a rear collection cylinder on the lower side, and a collection groove is provided on the frame, the collection groove being located above the rear collection cylinder; an internal blowing impeller is rotatably installed inside the lower shell, and when the sliding plate is located inside the upper plate, the dust filter membrane is just above the internal blowing impeller, and the dust filter membrane is concentric with the return blowing pipe, the lower end of the closed pipe is located inside the edge of the dust filter membrane, a discharge pipe is fixedly installed on the closed shell, the discharge pipe is connected to the external coalbed methane collection pipe, and the lower surface of the internal blowing impeller is in contact with the upper surface of the frame.

[0008] The beneficial effects of this invention compared with the prior art are: (1) In the primary filtration stage, this invention uses the kinetic energy of the coalbed methane itself to drive the impeller to rotate the scraper, automatically scrape off and collect the dust on the filter plate to prevent clogging. In the fine filtration stage, a portion of the filtered clean gas is used to automatically back-flush and clean the dust filter membrane through the closed pipe and the return pipe. No additional power source is required. Cleaning is achieved by the airflow itself, which reduces the risk of filter blockage and reduces the system pressure drop fluctuation, ensuring that coalbed methane extraction can be carried out continuously, stably and efficiently for a long time; (2) The collection box set in this invention is driven by a motor to collect the primary filtered dust in a cyclic manner. After the box is full, it automatically rotates to the work position. After reaching the designated position, the dust is automatically emptied by the push-out electric cylinder. From the slag hopper, the entire collection, transfer and cleaning process is completely sealed and automatic, which effectively avoids dust leakage and secondary dust problems during traditional manual dust removal, improves the working environment, protects the health of operators, and reduces maintenance frequency and labor costs; (3) The present invention integrates the primary filter mechanism, fine filter mechanism, collection mechanism and power transmission mechanism into a frame, which is compact and occupies a small area. The collection mechanism ensures dynamic tight fit between the bottom of the collection box and the lower bracket and between the upper tray and the frame through the pre-tension force of the vertical spring and the tension spring, respectively. Even under the condition of component rotation and vibration, it can effectively prevent dust from leaking from the rotation gap, and ensure the sealing reliability of the entire dust removal and collection process. Attached Figure Description

[0009] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a schematic diagram of the primary filtration mechanism of the present invention (I); Figure 3 is a schematic diagram of the primary filtration mechanism of the present invention (II); Figure 4 is a schematic diagram of the primary filtration mechanism of the present invention (III); Figure 5 is a schematic diagram of the collection mechanism of the present invention (I); Figure 6 is a schematic diagram of the collection mechanism of the present invention (II); Figure 7 is a schematic diagram of the collection mechanism of the present invention (III); Figure 8 is a schematic diagram of the collection mechanism of the present invention (IV); Figure 9 is a schematic diagram of the collection mechanism of the present invention (V); Figure 10 is a schematic diagram of the fine filtration mechanism of the present invention (I); Figure 11 is a schematic diagram of the fine filtration mechanism of the present invention (II); Figure 12 is a schematic diagram of the fine filtration mechanism of the present invention (III); Figure 13 is a schematic diagram of the fine filtration mechanism of the present invention (IV); Reference numerals: 101-Frame; 102-Primary filtration box; 103-Inlet pipe; 104-Lower plate; 105-Scraping groove; 106-Impeller; 107-Upper scraper; 108-Lower scraper; 109-Upper 110 - Connecting pipe; 111 - Inner filter plate; 201 - Motor frame; 202 - Motor; 203 - Lower support; 204 - Vertical sliding column; 205 - Top plate; 206 - Vertical spring; 207 - Slag hopper; 208 - Drop trough; 209 - Lower trough plate; 210 - Collection box; 211 - Upper trough plate; 212 - Push-out electric cylinder; 213 - Push-out block; 214 - Intermediate column; 215 - Lower bearing; 216 - Tensioning spring ; 217-Upper bearing; 218-Upper limit plate; 219-Hexagonal column; 301-Upper plate; 302-Sliding plate; 303-Handle; 304-Dust filter membrane; 305-Sealed shell; 306-Discharge pipe; 307-Lower shell; 308-Upper sealing plate; 309-Sealed pipe; 310-Inner air outlet pipe; 311-Return blow pipe; 312-Inner blow impeller; 313-Rear collection cylinder; 314-Collection trough; 315-Clamping pin. Detailed Implementation

[0010] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Examples

[0011] Referring to Figures 1-13, a dust separation device for coalbed methane extraction includes a frame 101. A primary filter, a fine filter, and a collection mechanism are mounted on the frame 101. The exhaust outlet of the primary filter is connected to the inlet of the fine filter. A collection mechanism is located below the primary filter. The primary filter is used to perform preliminary filtration of dust in the extracted coalbed methane. The fine filter is used to further collect and filter the fine dust in the coalbed methane. The collection mechanism is used to collect the dust from the primary filter. As shown in Figures 2-4, the primary filter includes a lower plate 104 fixedly mounted on the frame 101. A primary filter box 102 is fixedly mounted on the lower plate 104, and an impeller 106 is rotatably mounted inside the primary filter box 102. Multiple upper scraper rods 107 are coaxially fixedly installed on the impeller 106, and a lower scraper rod 108 is fixedly installed below the upper scraper rods 107. The outer surface of the upper scraper rods 107 is in contact with the inner wall of the primary filter box 102, and the lower surface of the lower scraper rod 108 is in contact with the upper surface of the lower plate 104. An upper outlet pipe 109 is fixedly installed on the primary filter box 102, and a connecting pipe 110 is fixedly installed on the upper outlet pipe 109. The connecting pipe 110 is connected to the input port of the fine filtration mechanism. An inner filter plate 111 is provided at the connection between the upper outlet pipe 109 and the primary filter box 102. A scraping groove 105 is provided on the lower plate 104, and an extraction pipe 103 is fixedly installed below the lower plate 104. The extraction pipe 103 is connected to the wellhead gas production pipeline.

[0012] The coalbed methane produced at the wellhead enters the intake pipe 103, then passes through the inner filter plate 111 and enters the upper outlet pipe 109. During this process, on the one hand, the inner filter plate 111 filters the dust in the coalbed methane, and some of the dust will remain on the inner filter plate 111. The remaining finer dust will enter the fine filtration mechanism through the connecting pipe 110 along with the coalbed methane. On the other hand, when the coalbed methane enters the intake pipe 103, it has a certain flow velocity. After the coalbed methane enters the primary filter box 102, it will blow the impeller 106 to rotate, which will drive the upper scraper 107 and the lower scraper 108 to rotate together. As the upper scraper 107 and the lower scraper 108 rotate, the upper scraper 107 scrapes the dust on the inner filter plate 111 onto the lower plate 104, and the lower scraper 108 scrapes the dust on the lower plate 104 into the scraping groove 105. Then the dust enters the collection mechanism through the scraping groove 105.

[0013] As shown in Figures 5-9, the collection mechanism includes two vertical sliding columns 204 slidably mounted on the frame 101 (the vertical sliding columns 204 move up and down relative to the frame 101). A top plate 205 is fixedly mounted on the vertical sliding column 204, and a lower support 203 is fixedly mounted below the vertical sliding column 204. A vertical spring 206 is provided between the top plate 205 and the frame 101. A discharge groove 208 is provided on the lower support 203, and a slag hopper 207 is fixedly mounted below the lower support 203. The discharge groove 208 is located above the slag hopper 207.

[0014] The collection mechanism also includes a motor frame 201 fixedly installed on the frame 101. A motor 202 is fixedly installed on the motor frame 201. A hexagonal column 219 is fixedly installed on the motor shaft of the motor 202. A middle column 214 is slidably installed on the hexagonal column 219. An upper groove plate 211 and a lower groove plate 209 are fixedly installed on the middle column 214. Each of the upper groove plate 211 and the lower groove plate 209 is provided with six through slots. A collection box 210 is fixedly installed between the through slots of the upper groove plate 211 and the lower groove plate 209. The collection box 210 is located below the scraping groove 105.

[0015] An upper limit plate 218 is fixedly installed on the intermediate column 214. An upper bearing 217 is rotatably installed on the intermediate column 214. A lower bearing 215 is rotatably installed on the frame 101. The inner ring of the lower bearing 215 is fixedly installed on the intermediate column 214. A tension spring 216 is provided between the lower bearing 215 and the upper bearing 217.

[0016] The collection mechanism also includes a push-out electric cylinder 212 fixedly installed on the frame 101. A push-out block 213 is fixedly installed on the output end of the push-out electric cylinder 212, and the push-out block 213 is located above the slag discharge hopper 207.

[0017] When one of the collection boxes 210 located below the scraping groove 105 is full of dust, the motor 202 drives the hexagonal column 219 and the middle column 214 to rotate, causing the lower groove plate 209, the collection box 210 and the upper groove plate 211 to rotate 60 degrees, so that the next empty collection box 210 reaches below the scraping groove 105. When the collection box 210 filled with dust reaches the drop groove 208, the push cylinder 212 extends, driving the push block 213 to descend. The push block 213 enters the collection box 210 below it and pushes all the dust in the collection box 210 onto the slag hopper 207. Then the dust slides out of the slag hopper 207 for collection. Then the push cylinder 212 retracts, the push block 213 rises, and the push block 213 leaves the collection box 210.

[0018] The vertical spring 206 is in a compressed state. The vertical spring 206 applies an upward thrust to the top plate 205, the vertical slide column 204 and the lower bracket 203, so that the upper surface of the lower bracket 203 and the lower surface of the lower groove plate 209 are kept in close contact, preventing the dust in the collection box 210 from leaking out of the lower bracket 203 and entering the external environment.

[0019] When the tension spring 216 is in a compressed state, it applies an upward thrust to the upper bearing 217 and the intermediate column 214, so that the upper groove plate 211 is kept in close contact with the lower surface of the frame 101. The hexagonal column 219 can slide inside the intermediate column 214. When the intermediate column 214 rotates, it rotates together with the inner ring of the lower bearing 215. The upper bearing 217 rotates relative to the intermediate column 214, so that the tension spring 216 will not twist when the intermediate column 214 rotates.

[0020] As shown in Figures 10-13, the fine filtration mechanism includes an upper plate 301 fixedly installed on a frame 101. A closed shell 305 is fixedly installed on the upper plate 301. An upper closed disc 308 is fixedly installed on the upper plate 301, located inside the closed shell 305. Three internal air outlet pipes 310 and three closed pipes 309 are fixedly installed on the upper closed disc 308. A return air pipe 311 is also fixedly installed on the upper closed disc 308, communicating with the three closed pipes 309. The return air pipe 311 is concentric with the upper closed disc 308. A sliding plate 302 is slidably installed inside the upper plate 301. Two dust filter membranes 304 are fixedly installed on the sliding plate 302. Two handles 303 are fixedly installed on the sliding plate 302. A slot is provided on the sliding plate 302. Two locking pins 315 are provided on the upper plate 301. In the normal state, one locking pin 315 is inserted into the slot of the sliding plate 302.

[0021] The fine filtration mechanism also includes a lower shell 307 fixedly installed on the upper side of the frame 101 and a rear collection cylinder 313 on the lower side, and a collection groove 314 is provided on the frame 101, which is located above the rear collection cylinder 313; an internal blowing impeller 312 is rotatably installed inside the lower shell 307. When the sliding plate 302 is located inside the upper plate 301, the dust filter membrane 304 is just above the internal blowing impeller 312, and the dust filter membrane 304 is concentric with the return pipe 311. The lower end of the closed pipe 309 is located inside the edge of the dust filter membrane 304. A discharge pipe 306 is fixedly installed on the closed shell 305. The discharge pipe 306 is connected to the external coalbed methane collection pipe. The lower surface of the internal blowing impeller 312 is in contact with the upper surface of the frame 101.

[0022] After the coalbed methane enters the lower shell 307 through the connecting pipe 110, it will drive the internal blowing impeller 312 to rotate. The coalbed methane flows upward through the dust filter membrane 304 inside the closed shell 305. The dust filter membrane 304 isolates the fine dust in the coalbed methane. After the coalbed methane passes through the dust filter membrane 304, half of the coalbed methane enters the discharge pipe 306 through the internal outlet pipe 310 and then enters the external collection pipe for collection. The other half of the coalbed methane enters the return blowing pipe 311 through the closed pipe 309. The coalbed methane backflows through the return blowing pipe 311 to the center of the upper surface of the dust filter membrane 304, backflowing the dust filter membrane 304 and shaking the fine dust on the dust filter membrane 304 into the lower shell 307. The internal blowing impeller 312 pushes the fine dust in the lower shell 307 through the collection groove 314 to the rear collection cylinder 313 for collection.

[0023] After the dust filter membrane 304 has been used for a period of time, it needs to be replaced. At this time, the locking pin 315 is pulled out of the slot of the sliding plate 302. Then, the sliding plate 302 can be slid relative to the upper plate 301 by pulling the handle 303, so that another dust filter membrane 304 enters the inner side of the closed shell 305. The used dust filter membrane 304 leaves the closed shell 305. At this time, the slot of the sliding plate 302 reaches the other locking pin 315. Then, the other locking pin 315 is inserted into the slot of the sliding plate 302, and the dust filter membrane 304 can be replaced without the need for the equipment to be shut down for a long time to handle the dust filter membrane 304.

Claims

1. A dust separation device for coalbed methane extraction, comprising a frame (101), characterized in that, A primary filtration mechanism, a secondary filtration mechanism, and a collection mechanism are provided on the frame (101). The exhaust outlet of the primary filtration mechanism is connected to the inlet of the secondary filtration mechanism, and a collection mechanism is provided below the primary filtration mechanism. The primary filtration mechanism includes a lower plate (104) fixedly installed on the frame (101). A primary filter box (102) is fixedly installed on the lower plate (104). An impeller (106) is rotatably installed inside the primary filter box (102). Multiple upper scrapers (107) are fixedly installed coaxially on the impeller (106). A lower scraper (108) is fixedly installed below the upper scrapers (107). The outer surface of the upper scrapers (107) is flush with the primary filter box. The inner wall of (102) is fitted together, and the lower surface of the lower scraper (108) is fitted together with the upper surface of the lower plate (104); an upper outlet pipe (109) is fixedly installed on the primary filter box (102), and a connecting pipe (110) is fixedly installed on the upper outlet pipe (109). The connecting pipe (110) is connected to the input port of the fine filter mechanism. An inner filter plate (111) is provided at the connection between the upper outlet pipe (109) and the primary filter box (102); a scraping groove (105) is provided on the lower plate (104), and an inlet pipe (103) is fixedly installed below the lower plate (104). The inlet pipe (103) is connected to the wellhead gas production pipeline.

2. The dust separation device for coalbed methane extraction as described in claim 1, characterized in that, The collecting mechanism includes two vertical sliding columns (204) slidably mounted on the frame (101). A top plate (205) is fixedly mounted on the vertical sliding columns (204). A lower bracket (203) is fixedly mounted below the vertical sliding columns (204). A vertical spring (206) is provided between the top plate (205) and the frame (101). A discharge groove (208) is provided on the lower bracket (203). A slag hopper (207) is fixedly mounted below the lower bracket (203). The discharge groove (208) is located above the slag hopper (207). The collecting mechanism also includes a motor frame (201) fixedly mounted on the frame (101). A motor (202) is fixedly mounted on the motor frame (201). A hexagonal column (219) is fixedly mounted on the motor shaft of the motor (202). A middle column (214) is slidably mounted outside the hexagonal column (219). An upper groove plate (211) and a... The lower grooved plate (209), the upper grooved plate (211), and the lower grooved plate (209) are each provided with six through slots. A collection box (210) is fixedly installed between the through slots of the upper grooved plate (211) and the lower grooved plate (209). The collection box (210) is located below the scraping groove (105). An upper limit plate (218) is fixedly installed on the intermediate column (214). An upper bearing (217) is rotatably installed on the intermediate column (214). The frame (101) is... The lower bearing (215) is rotatably mounted, and the inner ring of the lower bearing (215) is fixedly mounted to the intermediate column (214). A tension spring (216) is provided between the lower bearing (215) and the upper bearing (217). The collecting mechanism also includes a push-out electric cylinder (212) fixedly mounted on the frame (101). A push-out block (213) is fixedly mounted on the output end of the push-out electric cylinder (212), and the push-out block (213) is located above the slag hopper (207).

3. The dust separation device for coalbed methane extraction as described in claim 1, characterized in that, The fine filtration mechanism includes an upper plate (301) fixedly mounted on a frame (101), a sealed shell (305) fixedly mounted on the upper plate (301), an upper sealing disc (308) fixedly mounted on the upper plate (301), the upper sealing disc (308) being located inside the sealed shell (305), three internal air outlet pipes (310) and three sealing pipes (309) fixedly mounted on the upper sealing disc (308), and a return air pipe (310) also fixedly mounted on the upper sealing disc (308). 11) The return pipe (311) is connected to three closed pipes (309), and the return pipe (311) is concentric with the upper closed plate (308); a sliding plate (302) is slidably installed in the upper plate (301), two dust filter membranes (304) are fixedly installed on the sliding plate (302), two handles (303) are fixedly installed on the sliding plate (302), a slot is provided on the sliding plate (302), and two locking pins (315) are provided on the upper plate (301). In normal operation, a locking pin (315) is inserted into the slot of the sliding plate (302); the fine filtration mechanism also includes a lower shell (307) fixedly installed on the upper side of the frame (101) and a rear collection cylinder (313) on the lower side, and a collection groove (314) is provided on the frame (101), the collection groove (314) being located above the rear collection cylinder (313); an internal blowing impeller (312) is rotatably installed inside the lower shell (307), when the sliding plate (302) is located on the upper plate (301) Inside, the dust filter membrane (304) is located just above the internal blowing impeller (312), and the dust filter membrane (304) is concentric with the return blowing pipe (311). The lower end of the sealing pipe (309) is located inside the edge of the dust filter membrane (304). The discharge pipe (306) is fixedly installed on the sealing shell (305). The discharge pipe (306) is connected to the external coalbed methane collection pipe. The lower surface of the internal blowing impeller (312) is in contact with the upper surface of the frame (101).

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