Gas extraction system and extraction method in the upper corner of the coal mining face

Abstract

This invention discloses a gas extraction system for the upper corner of a coal mining face, comprising a traveling mechanism, an extraction mechanism, and a control mechanism. The traveling mechanism enables movement; the extraction mechanism monitors the goaf status and extracts gas; and the control mechanism receives signals, analyzes and processes the data, and issues extraction commands accordingly. This invention also discloses a method for extracting gas from the upper corner of a coal mining face, comprising the following steps: determining extraction parameters for the goaf; installing the extraction system on-site; activating all electrical components; collecting and processing information to obtain analysis results; issuing relevant action commands based on the analysis results, adjusting the extraction position, and then completing gas extraction in the current area; confirming completion of extraction once the gas concentration in the goaf meets safety standards. This invention belongs to the field of coal mine gas extraction technology and solves the problem of existing extraction equipment having an unreasonable structure and failing to extract gas in a timely manner.

Description

Technical Field

[0001] This invention belongs to the field of coal mine gas extraction technology, and relates to a gas extraction system for the upper corner of a coal mining face. This invention also relates to a method for gas extraction from the upper corner of a coal mining face. Background Technology

[0002] Article 498 of the Coal Mine Safety Regulations stipulates that the gas alarm concentration in the return air corner of a coal mining face should be ≥1%. In recent years, the production scale of mines has been developing towards larger scale and greater scale. Affected by the increase in mining capacity and the adjustment of ventilation methods, coupled with the interference of mining operations, the gas exceedance problem is very likely to occur in the return air corner of the working face, posing a hidden danger to the safe production of the mine.

[0003] Coal mine gas drainage is a fundamental measure for preventing coal mine gas disasters and a reliable means of preventing gas exceedances and gas explosions. Currently, the most commonly used technical measures for gas drainage in the upper corner of the coal face are pipe-insertion drainage and buried pipe drainage. However, in field applications, pipe-insertion drainage has a relatively small gas control area in the goaf and its drainage effect is poor; while buried pipe drainage involves burying pipelines in the goaf, resulting in material waste and potentially expanding the area of ​​spontaneous combustion zones due to goaf drainage, increasing the difficulty of mine fire prevention and extinguishing work.

[0004] Therefore, there is an urgent need to develop a gas extraction system and method for the upper corner of the coal mining face to solve the problems existing in mine safety production. Summary of the Invention

[0005] The purpose of this invention is to provide a gas extraction system for the upper corner of a coal mining face, which solves the problems of unreasonable structure of existing extraction equipment and untimely gas extraction.

[0006] Another objective of this invention is to provide a method for extracting gas from the upper corner of a coal mining face, which solves the problem that the existing technical measures are unreasonable and the gas control effect in the upper corner of the coal mining face is poor.

[0007] The technical solution adopted in this invention is a gas extraction system for the upper corner of a coal mining face, comprising three parts: a traveling mechanism, an extraction mechanism, and a control mechanism. The traveling mechanism enables the entire system to move; the extraction mechanism monitors the goaf status and extracts gas, and the extraction trunk pipe in the extraction mechanism is connected to the extraction pipeline of the working face to realize gas transportation; the control mechanism controls each functional unit, receives signals, performs data analysis and processing, and issues extraction commands appropriately.

[0008] Another technical solution adopted in this invention is a method for extracting gas from the upper corner of a coal mining face, which utilizes the aforementioned gas extraction system for the upper corner of a coal mining face and is implemented according to the following steps: Step 1: Determine the extraction parameters for the goaf in the coal mining face; Step 2: Install the sampling system on site; Step 3: Start all electrical components, deploy the traveling mechanism, conduct inspections, and collect relevant data and image information; Step 4: The control mechanism completes information collection and processing, and obtains the analysis results; Step 5: The control mechanism issues relevant action instructions based on the analysis results, the traveling mechanism completes the adjustment of the extraction position, and the extraction mechanism completes the gas extraction of the current area. Step 6: Once the gas concentration in the goaf has been reduced by extraction and meets safety standards, the extraction is confirmed to be complete, and the relevant components are removed.

[0009] The beneficial effects of this invention include the following aspects: 1) The extraction system of this invention can automatically monitor gas information in the goaf, and perform precise extraction by dividing the goaf into zones according to the gas distribution. The control mechanism can reasonably control the extraction range and extraction negative pressure, achieving precise zoning and treatment of gas in the goaf. At the same time, the goaf inspection component performs real-time inspection of the internal conditions of the goaf and adjusts the extraction parameters in a timely manner. 2) The extraction method of this invention, through model establishment, on-site inspection, and analysis and calculation, adopts corresponding extraction parameters according to the internal conditions of the goaf, effectively solving the problem of gas extraction in the goaf. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of the extraction system of the present invention; Figure 2 This is a structural block diagram of the traveling mechanism in the extraction system of the present invention; Figure 3 This is a structural block diagram of the extraction mechanism in the extraction system of the present invention; Figure 4 This is a structural block diagram of the goaf extraction component in the extraction system of the present invention; Figure 5 This is a structural block diagram of the control mechanism in the extraction system of the present invention.

[0011] In the diagram, 1. Traveling mechanism, 2. Extraction mechanism, 3. Control mechanism, 11. Casters, 12. Support column, 13. Traction assembly, 14. Hydraulic support, 15. Top support plate, 16. Sealing assembly, 161. Compressed air pipe, 162. Electrically controlled valve one, 163. Airbag, 17. Base; 21. Extraction main pipe, 22. Extraction branch pipe, 23. Goaf inspection assembly, 231. Multi-parameter inspection instrument, 232. 3D laser scanner, 233. 3D rotating camera, 24. Goaf extraction assembly, 241. Suction head, 242. Guide motor, 243. Electrically controlled valve two; 31. Information acquisition unit, 32. Traveling control unit, 33. Extraction control unit, 34. Network cable, 35. Power cord, 36. Communication optical cable, 37. Explosion-proof box, 38. Electrical cabinet, 4. Industrial ring network switch. Detailed Implementation

[0012] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0013] Reference Figure 1 The structure of the gas extraction system for the upper corner of the coal mining face of the present invention includes three parts: a traveling mechanism 1, an extraction mechanism 2, and a control mechanism 3. The traveling mechanism 1 mainly realizes the movement of the entire system; the extraction mechanism 2 mainly realizes the monitoring of the goaf status and gas extraction. The extraction trunk pipe 21 in the extraction mechanism 2 is connected to the gas extraction pipeline of the working face to realize gas transportation; the control mechanism 3 controls each functional unit, receives signals, performs data analysis and processing, and issues extraction commands in a reasonable manner.

[0014] Reference Figure 2 The structure of the traveling mechanism 1 includes a base 17 as a supporting foundation, a set of casters 11 installed on both sides of the base 17, and lifting support columns 12 installed on both sides of the upper surface of the base 17. A total of four support columns 12 are connected upward to a support truss. A top support plate 15 that can be opened and closed is set above the support truss. Multiple tracks are set on the upper surface of the support truss for installing various monitoring instruments in the goaf inspection component 23. A traction component 13 is installed at the front of the base 17. The traction component 13 is fixedly connected to the hydraulic support column 14 in the working face. The traction component 13 can extend and retract by itself. The traction component 13 moves together with the movement of the hydraulic support column 14, driving the traveling mechanism 1 to move together. A sealing component 16 is installed at the front end of the base 17 for sealing the goaf.

[0015] The structure of the sealed component 16 includes a compressed air pipe 161, the inlet end of which is connected to the mine compressed air system and is equipped with an electrically controlled valve 162, and the outlet end of the compressed air pipe 161 is connected to the airbag 163.

[0016] The top support plate 15 is a double-layered frame that can be opened and closed. The double-layered frame is opened or closed by a separate hydraulic device. Each layer of the frame is welded from steel pipes. Each layer of the frame is evenly distributed with gaps (preferably 30cm×30cm). All gaps are equipped with metal mesh, which not only serves to block stones falling from above the top support plate 15, but also protects the traveling mechanism 1, extraction mechanism 2 and control mechanism 3 below the top support plate 15. The gas in the goaf can also flow normally through the metal mesh to ensure that the gas measured by the monitoring instrument belongs to this area.

[0017] Reference Figure 3 , Figure 4 The extraction mechanism 2 consists of an extraction main pipe 21 and a goaf inspection component 23. The outlet end of the extraction main pipe 21 is connected to the extraction pipeline in the roadway. Multiple extraction branch pipes 22 are installed on the extraction main pipe 21, and each extraction branch pipe 22 is equipped with a goaf extraction component 24. Each goaf extraction component 24 includes an air suction head 241, a guide motor 242, and an electrically controlled valve 243. The air suction head 241 is located at the end of the extraction branch pipe 22 and is fixed to the end of the drive shaft of the guide motor 242. The air suction head 241 is connected to the electrically controlled valve 243 through the guide motor 242. The electrically controlled valve 243 is located in the extraction branch pipe 22 near the extraction pipeline. Each goaf extraction component 24 is used to perform precise extraction of different blocks in the goaf. The goaf inspection component 23 includes a multi-parameter inspection instrument 231, a three-dimensional laser scanner 232, and a three-dimensional rotating camera 233. Multiple guide rails are installed on the support truss below the top support plate 15. The multi-parameter inspection instrument 231, the three-dimensional laser scanner 232, and the three-dimensional rotating camera 233 are respectively moved and set on their respective guide rails. They move according to the set path and monitor upwards through the metal mesh. The goaf inspection component 23 is used to monitor the goaf status and the gas in the goaf.

[0018] Reference Figure 5 The control mechanism 3 consists of an explosion-proof box 37, which contains a power adapter and a PLC. The PLC is equipped with an interactive interface and a switch. The PLC in the explosion-proof box 37 is connected to the information acquisition unit 31, the movement control unit 32, and the extraction control unit 33 via network cable 34. The power adapter in the explosion-proof box 37 is electrically connected to the information acquisition unit 31, the movement control unit 32, and the extraction control unit 33 via power cord 35. The power adapter in the explosion-proof box 37 is connected to the electrical cabinet 38 via power cord 35. The electrical cabinet 38 supplies power to the entire system. The PLC's switch is connected to the industrial ring network switch 4 via communication optical cable 36 to transmit signals to the terminal industrial ring network, enabling remote monitoring and operation. The information acquisition unit 31, the travel control unit 32, and the extraction control unit 33 are interconnected via network cable 34. In addition, the information acquisition unit 31 is connected to the goaf inspection component 23 in the extraction mechanism 2 to collect the monitoring information of the goaf inspection component 23, and to analyze and 3D model the monitoring information. The travel control unit 32 is connected to the motion components in the travel mechanism 1 to control the closed state of the sealing component 16, control the lifting and lowering of the four support columns 12 and the opening and closing of the top support plate 15, control the instruments in the goaf inspection component 23 to move along their respective tracks for monitoring without blind spots, and control the stepping operation of the traction component 13 to move the base 17.

[0019] The working principle of the extraction system of this invention is as follows: 1) The traveling mechanism 1 mainly provides movement for the entire system. Two casters 11 are installed on each side of the base 17. The base 17 is connected to the hydraulic support 14 on the working surface via a traction assembly 13. The traveling mechanism 1 moves synchronously with the movement of the hydraulic support 14. Support columns 12 capable of lifting and lowering are installed on each side of the base 17. An openable top support plate 15 is installed at the top of the four support columns 12 via a support truss to protect all equipment inside the goaf extraction space. A sealing assembly 16 is installed at the front end of the base 17. The sealing assembly 16 seals the goaf after expanding. An electrically controlled valve 162 in the sealing assembly 16 controls the air supply status (open, closed, and valve opening) of the compressed air pipe 161, controlling the compressed air pipe 161 to provide air to the airbag 163. (See...) Figure 1 and Figure 2 .

[0020] 2) The extraction mechanism 2 mainly realizes the monitoring of the goaf status and the zoned gas extraction. The extraction main pipe 21 is connected to the extraction pipeline of the working face (roadway) to realize gas transportation. Multiple extraction branch pipes 22 are also installed on the extraction main pipe 21. Each extraction branch pipe 22 is equipped with a set of goaf extraction components 24, see Figure 3 and Figure 4 .

[0021] Precise extraction is performed in different areas of the goaf; in the goaf inspection component 23, the multi-parameter inspection instrument 231 is used to continuously inspect the gas concentration inside the goaf, the three-dimensional laser scanner 232 is used to perform high-speed scanning inside the goaf and collect complete information inside the goaf, and the three-dimensional rotating camera 233 is used to collect video inside the goaf.

[0022] In the goaf extraction assembly 24, the electrically controlled valve 243 controls the extraction negative pressure of the suction head 241; the guide motor 242, according to the instructions of the control mechanism 3, can realize the 360° rotation and extension of the suction head 241, achieving precise extraction within the goaf; the suction head 241 is equipped with several small suction holes to achieve the intake of methane gas within the goaf. Electrical connections are established through circuits to provide power and signal interaction between the components and the control mechanism 3. These electrical connections include power supply links and signal transmission links, which are described below: a) Power supply link: In the control mechanism 3, the electrical cabinet 38 transmits power to the extraction control unit 33 through the explosion-proof box 37 and the power line 35. The extraction control unit 33 then connects to the second electric valve 243 and the guide motor 242 to provide working power for both, provide switching drive power for the second electric valve 243, and provide rotation and extension power for the guide motor 242. b) Signal transmission link: The extraction control unit 33 sends commands to the second electrically controlled valve 243 via a signal line to control its opening and closing status, thereby adjusting the extraction negative pressure; the extraction control unit 33 sends commands to the guide motor 242 via a signal line to control the angle rotation and extension length, and the guide motor 242 then drives the suction head 241 to rotate and extend, achieving precise positioning of the suction head 241; the real-time opening, rotation angle, and extension position of the second electrically controlled valve 243 and the guide motor 242 are fed back to the extraction control unit 33 via a signal line, forming a closed-loop control.

[0023] c) The extraction process utilizes a closed pipeline to ensure efficient gas flow from the intake head 241 to the extraction branch pipe 22. This involves the gas flow path and sealing requirements, as explained below: Airflow path: The surface of the suction head 241 has several small holes to directly draw in the gas from the goaf; the suction head 241 is connected to the guide motor 242 through a hollow connecting pipe, and the gas enters the hollow channel of the guide motor 242 through the suction head 241; the other end of the guide motor 242 is connected to the inlet end of the second electrically controlled valve 243 through a pipeline, and the gas flows into the second electrically controlled valve 243 through the guide motor 242; the outlet end of the second electrically controlled valve 243 is connected to the extraction branch pipe 22, and finally transported to the extraction pipeline of the roadway through the extraction main pipe 21; Sealing requirements: All channel connections must be sealed to ensure airtightness and prevent gas leakage from affecting extraction efficiency or causing safety hazards.

[0024] 3) For control mechanism 3, see Figure 5The information acquisition unit 31, the travel control unit 32, and the extraction control unit 33 communicate with each other bidirectionally via data interfaces and software protocols. The information acquisition unit 31 synchronously transmits processed information to the travel control unit 32 and the extraction control unit 33 via a data bus, providing decision-making information. The travel control unit 32 and the extraction control unit 33 engage in status feedback and collaborative control interaction. Status information from the travel control unit 32, such as movement to position signals and sealing completion signals, is fed back to the extraction control unit 33 to ensure the extraction component operates in a stable environment. The extraction control unit 33 sends collaborative adjustment commands to the travel control unit 32, such as fine-tuning the position of the traction component 13 and the base 17 to facilitate extraction.

[0025] These three units are connected to relevant components in the extraction mechanism 2 and the traveling mechanism 1 via network cable 34 and power cable 35. They are also connected to the industrial ring network switch 4 via communication optical cable 36 (flame-retardant communication optical cable for coal mines) through the switch in the explosion-proof box 37, enabling remote data interaction with the ground terminal. Specific details are as follows: Information acquisition unit 31 is connected to extraction mechanism 2 via network cable 34, collects monitoring information obtained by goaf inspection component 23, analyzes the monitoring information and performs 3D modeling; travel control unit 32 is connected to travel mechanism 1 via network cable 34, controls the closed state of sealing component 16, controls the lifting and lowering of support column 12 and the opening and closing of top support plate 15, controls the movement of each monitoring instrument in goaf inspection component 23, and controls traction component 13 to pull base 17 to move; extraction control unit 33 is pre-set with mine gas extraction model, and controls goaf extraction component 24 in extraction mechanism 2 according to the analysis results (of information acquisition unit 31), and adjusts the azimuth angle and extraction parameters of suction head 241 by changing the state of electric control valve 243 and guide motor 242, so as to achieve reasonable adjustment of extraction parameters and extraction position.

[0026] 4) Control mechanism 3 includes both information processing hardware (computer-related configuration) and pre-stored information processing software, as explained below: a) Using a 3D laser scanner 232 and a 3D rotating camera 233, information such as the shape and image of the goaf are acquired and transmitted to the information acquisition unit 31 to perform 3D simulation modeling of the goaf.

[0027] b) Using the multi-parameter inspection instrument 231, the gas concentration (methane, carbon monoxide, oxygen) in the goaf is monitored in real time, and the measurement results are transmitted to the information acquisition unit 31 to finally form a three-dimensional cloud map of the gas inside the goaf.

[0028] c) The PLC's interactive interface or the terminal system's display screen displays real-time information about the goaf (including but not limited to the goaf shape, goaf images, etc.), or allows for remote manual operation (multi-angle scanning and image angle adjustment). It supports historical queries based on time, gas concentration warnings, and other conditions, supports report generation and export, supports the generation of 3D status diagrams, and supports remote modification of the control parameters (such as scanning cycle, scanning frequency, and scanning method) of the multi-parameter inspection instrument 231, 3D laser scanner 232, and 3D rotating camera 233.

[0029] 5) Explanation of the control signals issued by the travel control unit 32 and the extraction control unit 33 respectively.

[0030] The travel control unit 32 is connected to the travel mechanism 1 via a network cable 34. It sends control signals for three types of actions: base movement, support protection, and goaf sealing. Based on the coordination requirements of the extraction control unit 33, it controls the extension and retraction of the traction component 13, causing the base 17 to move synchronously with the hydraulic support 14 for fine-tuning to ensure the extraction component is aligned with the target area. A "stop command" is sent, and the displacement sensor on the base 17 determines when it has moved to a preset position, issuing a stop signal to prevent overtravel. A "lifting command" is sent to the support columns 12, controlling the hydraulic drive to simultaneously raise / lower the four support columns 12, adjusting the height of the top support plate 15 to adapt to the height of the goaf roof, ensuring the protection range covers the extraction area. An "opening / closing command" is sent to the top support plate 15, controlling its expansion / closure to prevent roof breakage and damage to the extraction component. Before the travel mechanism 1 moves, a "venting command" is sent, controlling the electrically controlled valve 162 to vent in reverse, causing the airbag 163 to contract and preventing obstruction of movement. Send an "opening adjustment command" to the sealing component 16 to adjust the opening and closing of the electric control valve 162 and the channel size, control the amount of air supplied to the airbag 163 by the compressed air pipe 161, so that the airbag 163 expands to seal the gap between the goaf and the working face, reducing gas leakage or fresh air mixing.

[0031] Based on the analysis results of the information acquisition unit 31, the extraction control unit 33 sends control signals to the goaf extraction component 24 to achieve precise positioning extraction and flow regulation. It sends a "rotation angle command" to the guide motor 242, controlling its 360° rotation to align the suction head 241 with the gas-rich area. It sends a "telescopic length command" to control the telescopic amount of the guide motor 242, adjusting the depth of the suction head 241 in the goaf to ensure proximity to high-concentration gas areas. It sends an "opening command" to the electrically controlled valve 243, adjusting the valve opening to control the extraction negative pressure, ensuring extraction efficiency while preventing spontaneous combustion of residual coal in the goaf due to excessive negative pressure. It sends a "switch command," issuing a shut-off signal when the gas concentration is below the critical value to stop extraction; and an emergency open signal when the gas concentration exceeds the limit to intensify extraction.

[0032] The method for extracting gas from the upper corner of a coal mining face according to the present invention utilizes the aforementioned gas extraction system for the upper corner of a coal mining face and is implemented according to the following steps: Step 1: Using a comprehensive approach combining numerical simulation, similarity simulation, theoretical analysis, and engineering experiments, while considering both mine fire prevention and extinguishing requirements and the need for gas control in the upper corner, determine the reasonable parameters (extraction negative pressure, extraction range) for goaf extraction in the coal mining face. Specifically: Numerical simulation: Based on the geological conditions and mining parameters of the goaf, a three-dimensional flow field model is established to simulate the gas migration law under different negative pressures and extraction ranges, analyze the gas concentration distribution, flow velocity and air leakage intensity, and focus on simulating the impact of extraction negative pressure on the "three spontaneous combustion zones" of the goaf, so as to avoid the expansion of the oxidation zone due to excessive negative pressure leading to oxygen influx. Similarity simulation: A 1:50 physical model was built to simulate the collapse morphology and gas seepage characteristics of the goaf. The location of the extraction port and the negative pressure value were changed to observe the relationship between gas extraction efficiency and the oxidation and heating rate of residual coal. Theoretical analysis: Based on the gas migration equation and the coal spontaneous combustion kinetics theory, the critical extraction negative pressure is calculated, and the minimum negative pressure, maximum negative pressure, and extraction range are obtained. Engineering experiment: Select typical areas on site for trial extraction, deploy sensors to monitor gas concentration, negative pressure and oxygen content, compare extraction efficiency and fire prevention and extinguishing effect under different parameters, and finally determine the parameters suitable for this mine; Finally, the extraction negative pressure and extraction range were determined. The extraction negative pressure includes low-gas areas to avoid excessive air extraction, high-gas areas to improve extraction efficiency, and near-spontaneous combustion risk areas to control air leakage. The extraction range includes gas accumulation areas along the strike, areas along the dip to avoid the main ventilation field, and areas along the vertical direction to avoid blockage by falling debris across the goaf.

[0033] Step 2: Install the sampling system of this invention on site and connect the relevant components: A gas block extraction system is installed in the goaf of the working face, and the extraction trunk 21 is reliably connected to the extraction pipeline laid in the roadway. The base 17 is reliably connected to the hydraulic support 14 of the working face through the traction component 13.

[0034] Step 3: Start each electrical component, conduct inspections, and collect relevant data and image information: The travel mechanism 1 is deployed, and the goaf inspection component 23 in the extraction mechanism 2 begins to inspect and collect relevant data and image information. The support columns 12 around the base 17 are raised simultaneously, and the top support plate 15 is opened to ensure that the relevant components in the system are not damaged by falling roof debris. The multiple parameter inspection instruments 231, 3D laser scanner 232, and 3D rotating camera 233 in the goaf inspection component 23 continuously inspect and collect relevant data and image information on their respective guide rails along predetermined routes.

[0035] Step 4: Control mechanism 3 completes information collection and processing, and obtains the analysis results: The goaf inspection component 23 transmits the real-time collected data and image information to the control mechanism 3 via the network cable 34. The information acquisition unit 31 in the control mechanism 3 records all the information and analyzes and calculates it. Based on the latest information collected about the goaf, the information acquisition unit 31 completes a three-dimensional model of the current monitored goaf interior.

[0036] Step 5: The control mechanism 3 issues relevant action commands based on the analysis results. The travel control unit 32 controls the travel mechanism 1 to first complete the adjustment of the extraction position, and then the extraction control unit 33 controls the goaf extraction component 24 in the extraction mechanism 2 to complete the gas extraction in the current area. Adjusting the extraction position: First, the travel control unit 32 controls the travel mechanism 1 to move. The travel control unit 32 receives the coordinates sent by the information acquisition unit 31. The travel control unit 32 sends a command to the traction component 13 to control the extension and retraction of the traction component 13, which drives the base 17 to move synchronously with the hydraulic support 14. Then, it sends an "extension command" to the support column 12, which raises the four support columns 12 synchronously, raising the top support plate 15 close to the top plate of the goaf, fixing the extraction position and preventing the top plate debris from falling. Protective extraction space: Based on the height of the goaf, an "opening and closing command" is sent to the top support plate 15 to control its unfolding angle, expand the protection range, and ensure that the goaf extraction component 24 and the goaf inspection component 23 work reliably within the protected area. Sealing the goaf: Send an "opening command" to the electrically controlled valve 162 of the sealing component 16 to control the compressed air pipe 161 to inflate the airbag 163, so that the airbag 163 expands and fits against the rock wall of the goaf, sealing the connection between the goaf where the base 17 is located and other areas, reducing the mixing of fresh air or gas leakage.

[0037] Secondly, the extraction control unit 33 locates the extraction target area: the extraction control unit 33 receives the three-dimensional coordinates of the gas-rich area generated by the information acquisition unit 31, and sends rotation and / or extension commands (or "rotation + extension commands") to the guide motor 242; adjusts extraction parameters: the extraction control unit 33 sends an "opening command" to the second electrically controlled valve 243, adjusts the valve opening according to the gas concentration, and controls the extraction negative pressure; receives the opening signal from the second electrically controlled valve 243 and the position signal from the guide motor 242 in real time, and issues a correction command when there is a deviation; multi-area coordinated extraction: commands are sent to the goaf extraction components 24 on different extraction branch pipes 22 to differentiate the angle, extension length and opening of the guide motor 242 and the second electrically controlled valve 243 in each component to avoid mutual interference.

[0038] Step 6: Once the gas concentration in this goaf has been reduced by extraction and meets safety standards, the extraction is confirmed as complete. Related components are then removed, and the process moves to the next working face. After the extraction operation has continued for a certain period of time, the information acquisition unit 31 collects information in real time through the goaf inspection component 23. The extraction control unit 33 can confirm that the gas concentration in this working face has decreased to meet the safety standard, and thus confirm that the extraction is completed. Then, the travel control unit 32 sends a command to the travel mechanism 1, which closes the top support plate 15, lowers the four support columns 12, and contracts the airbag 163. Both the travel mechanism 1 and the extraction mechanism 2 return to their initial contracted state. Once the traveling mechanism 1 has moved forward to its original position, gas extraction can begin at the next working face, and this cycle can continue.

[0039] This invention relates to a gas extraction system and method for the upper corner of a coal mining face. It features real-time monitoring, precise extraction, safety early warning, and autonomous movement. It addresses the extraction efficiency and safety issues encountered in current high-yield, high-efficiency coal seam gas extraction in the upper corner of mining faces, playing a crucial role in the control of gas in the upper corner of goaf areas. It has excellent application prospects and can be widely applied in the field of coal mining technology, providing strong support for safe and efficient mine production.

[0040] Example 1 According to the method of the present invention, the gas extraction system in the upper corner of the coal mining face described above is implemented according to the following steps: Step 1: Using a combination of numerical simulation, similarity simulation, theoretical analysis and engineering experiments, the reasonable spacing for goaf extraction in a certain coal mining face is determined to be 20m, and the extraction negative pressure is 7KPa. Step 2: Deploy the extraction system of the present invention in the goaf area of ​​the working face, with an initial control distance of 20m and an extraction negative pressure of 7KPa, and connect the extraction trunk 21 to the extraction pipeline in the roadway.

[0041] Step 3: Raise the support columns 12 around the base 17, open the top support plate 15, and the multi-parameter inspection instrument 231, 3D laser scanner 232, and 3D rotating camera 233 continuously inspect along their predetermined routes on their respective guide rails.

[0042] Step 4: Through the observation of the 3D rotating camera 233, the top plate of the goaf is relatively intact and presents an overall rectangular shape. The 3D laser scanner 232 scans and determines that the depth of the goaf extraction area is 20m, the height is 4m, and the width is 3m. The information acquisition unit 31 receives the monitoring signal in real time and performs internal modeling of the goaf, dividing the goaf into 100 cells, and each cell is numbered and its coordinates are determined.

[0043] Step 5: The multi-parameter inspection instrument 231 monitors the gas concentration (methane, carbon monoxide, oxygen) in the goaf in real time and transmits the monitoring results to the information acquisition unit 31. Based on the goaf modeling, three-dimensional cloud maps of methane, carbon monoxide, and oxygen are generated respectively.

[0044] Step 6: The extraction control unit 33 sends an instruction to the extraction mechanism 2. The goaf extraction component 24 performs block-based precise extraction in the gas-rich area (gas concentration > 3%) according to the number and coordinates provided by the information acquisition unit 31. The gas extraction concentration in the goaf is greatly increased, and the gas in the upper corner is effectively controlled.

[0045] Example 2 According to the method of the present invention, the gas extraction system in the upper corner of the coal mining face described above is implemented according to the following steps: Step 1: Determine the reasonable extraction step distance in the goaf through a combination of methods, including theoretical analysis, numerical simulation, similarity simulation, and laboratory analysis.

[0046] Step 2: Deploy the extraction system of this invention within the goaf area of ​​the working face. The multi-parameter inspection instrument 231, the three-dimensional laser scanner 232, and the three-dimensional rotating camera 233 continuously inspect along a predetermined route on the guide rail, omitting the modeling and precise extraction processes within the goaf area.

[0047] Step 3: As the mine face advances to the structural area, abnormal fluctuations in gas occur. The gas sensor at the upper corner of the face detects a gas concentration close to 0.7%. The multi-parameter inspection instrument 231 detects an increase in the variation of methane gas concentration inside the goaf. Near the upper corner, the gas concentration exceeds the set critical value. The information acquisition unit 31 promptly transmits the information to the extraction mechanism. The extraction mechanism 2 increases the extraction negative pressure by 3 kPa by adjusting the guide motor 242 and the electrically controlled valve 243 of the goaf extraction component, focusing on extraction in the gas-rich area (concentration exceeding 3%). The control mechanism 3 transmits the abnormal gas information to the ground technicians through the industrial ring network.

[0048] Step 4: After comprehensive analysis, the technicians determined that the main cause of the gas was a sudden increase in gas in the structural area, which flowed into the goaf through the return airflow, causing an increase in gas concentration in the upper corner. The operators immediately took action, reducing the coal cutting speed, adjusting the air pressure in the airbags of the sealing assembly 16 to ensure the goaf was sealed, and simultaneously increasing the extraction intensity of the goaf extraction assembly 24. The multi-parameter monitoring instrument 231 continuously monitored the gas conditions in the goaf and issued adjustment instructions in a timely manner.

[0049] Step 5: Through reasonable measures, the multi-parameter inspection instrument 231 monitored that the methane gas concentration inside the goaf gradually decreased to the critical value range, and the gas sensor in the upper corner of the working face monitored that the gas concentration dropped to 0.4%.

[0050] Example 3 According to the method of the present invention, the aforementioned gas extraction system for the upper corner of the coal mining face is used to regulate the extraction of gas from a goaf in a certain mine, and the following steps are followed: Step 1: Determine the reasonable extraction step distance in the goaf through a combination of methods, including theoretical analysis, numerical simulation, similarity simulation, and laboratory analysis.

[0051] Step 2: Deploy the extraction system of this invention within the goaf area of ​​the working face. The multi-parameter inspection instrument 231, the three-dimensional laser scanner 232, and the three-dimensional rotating camera 233 continuously inspect along predetermined routes on their respective guide rails. The modeling and precise extraction processes within the goaf area are omitted.

[0052] Step 3: The multi-parameter inspection instrument 231 detected that the concentrations of carbon monoxide and oxygen in the goaf exceeded the set critical values. The information acquisition unit 31 promptly transmitted the information to the extraction mechanism 2. The extraction mechanism 2 reduced the extraction negative pressure by 5 kPa and reduced the extraction range by 5 m by adjusting the guide motor 242 and the electric control valve 243 of the goaf extraction component 24. The control mechanism 3 transmitted the abnormal information to the ground technicians through the industrial ring network.

[0053] Step 4: Technicians comprehensively analyze and judge the spontaneous combustion situation of coal seams inside the goaf, and prepare fire prevention and extinguishing plans. Multi-parameter inspection instrument 231 continuously monitors the gas conditions inside the goaf. Sealing component 16 adjusts the air pressure of airbags to ensure the goaf is sealed. Extraction negative pressure adjustment reduces the air pressure difference inside and outside the goaf and reduces air leakage inside the goaf.

[0054] Step 5: Through reasonable measures, the multi-parameter inspection instrument 231 monitored that the concentrations of carbon monoxide and oxygen in the goaf gradually returned to the critical range, and the system restarted the modeling and precise extraction of the goaf.

[0055] Example 4 According to the method of the present invention, the gas extraction system in the upper corner of the coal mining face described above is implemented according to the following steps: Step 1: For a coal mining face with fault structure in a certain mine, a gas migration model of the goaf affected by the fault is established by combining numerical simulation with field detection. The extraction step distance is determined to be 15m, the initial extraction negative pressure is 5KPa, and the area within 20m of the fault is designated as the key monitoring area.

[0056] Step 2: When setting up the extraction system at the working face, add two additional sets of goaf inspection components 5m on both sides of the fault to ensure real-time monitoring of abnormal gas seepage in the fault zone; when connecting the extraction main pipe to the roadway extraction pipeline, use a reinforced sealing interface to prevent gas leakage under high negative pressure.

[0057] Step 3: During system operation, the 3D laser scanner 232 detected irregular collapse patterns in the goaf near the fault, forming a local gas accumulation space (2.5m high and 4m wide); the multi-parameter inspection instrument 231 showed that the methane concentration in this area reached 4.2%, far exceeding the critical value.

[0058] Step 4: The information acquisition unit 31 overlays and analyzes the gas data of the fault zone with the three-dimensional model. The extraction control unit 33 sends an instruction to the goaf extraction component 24 in the corresponding area: the guide motor 242 rotates to the fault dip direction of 30°, the extension length increases by 1.2m, and it is aligned with the center of the accumulation area; the opening of the second electric control valve 243 is adjusted to 80%, and the extraction negative pressure is increased to 8KPa.

[0059] Step 5: After continuous extraction for 30 minutes, the multi-parameter inspection instrument 231 detected that the methane concentration in the fault zone dropped to 1.8%, and the gas sensor in the upper corner showed that the concentration stabilized at 0.6%; the extraction control unit 33 gradually adjusted the negative pressure back to 5KPa to maintain normal extraction and ensure that the gas in the fault zone does not accumulate again.

[0060] Example 5 According to the method of the present invention, the gas extraction system in the upper corner of the coal mining face described above is implemented according to the following steps: Step 1: In response to the characteristics of the broken and easily collapsing roof in the goaf of a certain mine, the protection parameters of the extraction system were determined through similar simulation experiments: the unfolding angle of the top support plate 15 should cover a range of 1.5m above the extraction components, and the lifting response time of the support column 12 should not exceed 10 seconds, so as to quickly deal with the roof falling.

[0061] Step 2: When installing the extraction system, a wear-resistant steel plate is added to the surface of the top support plate 15, and a buffer spring can be added to the upper surface of the top support plate 15. Step 3: After the system starts, the 3D rotating camera 233 transmits the top plate image in real time. The information acquisition unit 31 detects that a piece of gravel with a volume of about 0.3m³ is about to fall at a distance of 0.8m from the extraction component and immediately issues a warning to the travel control unit 32.

[0062] Step 4: The travel control unit 32 synchronously executes the protection command: the support column 12 rises 0.5m within 5 seconds, the top support plate 15 quickly unfolds to the maximum angle to form a protective barrier; at the same time, the extraction control unit 33 suspends extraction in this area, and the guide motor 242 drives the suction head 241 to retract into the protection range.

[0063] Step 5: After the crushed stone falls onto the top support plate 15, the buffer spring effectively absorbs the impact force, and no parts of the system are damaged. After the top support plate 15 stabilizes, the travel control unit 32 controls the support column 12 to fall back and the top support plate 15 to reset. The extraction control unit 33 restarts the extraction, the guide motor 242 is repositioned to the original extraction point, and the extraction parameters are restored to the set values ​​(negative pressure 6KPa, extraction range 3m×2m).

[0064] Example 6 According to the method of the present invention, the gas extraction system in the upper corner of the coal mining face described above is implemented according to the following steps: Step 1: Based on the mine recovery schedule, calculate the gas migration pattern during the working face advance through theoretical analysis: When the daily advance of the working face is 2.5m, the gas-rich area in the goaf will migrate to the depth of the goaf by 0.8m / day, and the extraction area needs to be adjusted accordingly.

[0065] Step 2: When deploying the extraction system, a set of movable extraction branch pipes 22 are set at 5m intervals on the extraction main pipe 21. Each set of extraction branch pipes 22 is equipped with an independent goaf extraction component 24 to form an extraction zone along the direction.

[0066] Step 3: When the working face advances to the 5th day, the goaf inspection component 23 inspects according to the preset route and finds that the gas concentration in the original extraction area (30m away from the working face) has dropped to 1.2%, while a new enrichment area (methane concentration 3.5%) appears at a depth of 35m and is continuously distributed.

[0067] Step 4: The information acquisition unit 31 matches and analyzes the gas migration data with the progress of the advance to generate a dynamic extraction area adjustment plan; the travel control unit 32 controls the traction component 13 to drive the base 17 to move forward 5m synchronously with the hydraulic support column 14, and the support column 12 automatically adjusts to 2.3m according to the height of the top plate at the new position.

[0068] Step 5: The extraction control unit 33 coordinates the coordinated action of multiple groups of goaf extraction components 24: the electrical control valve 243 of the original 30m extraction branch pipe 22 is closed, and the extraction component of the 35m branch pipe is opened; the guide motors 242 in the three extraction components on the left rotate 15° uniformly, and the guide motors 242 in the two extraction components on the right rotate -10° to form a fan-shaped extraction area covering the migrated enriched area; the extraction negative pressure of each component is set to 6-7.5KPa according to the concentration difference to achieve differentiated and precise extraction.

[0069] Step 6: Continuous monitoring shows that multi-regional coordinated extraction keeps the overall gas concentration in the goaf below 1.5%, and the gas concentration in the upper corner is stable at 0.5%, meeting the safety requirements for continuous advancement of the working face.

Claims

1. A gas extraction system for the upper corner of a coal mining face, characterized in that: It consists of three parts: a traveling mechanism (1), a gas extraction mechanism (2), and a control mechanism (3). The traveling mechanism (1) enables the entire system to move and move. The gas extraction mechanism (2) enables the monitoring of the goaf status and gas extraction. The extraction trunk pipe (21) in the extraction mechanism (2) is connected to the gas extraction pipeline of the working face to realize gas transportation. The control mechanism (3) controls each functional unit, receives signals, performs data analysis and processing, and issues extraction instructions in a reasonable manner. The structure of the traveling mechanism (1) includes a base (17), with casters (11) installed on both sides of the base (17), and liftable support columns (12) installed on both sides of the upper surface of the base (17). A total of four support columns (12) are connected to a support truss. An openable top support plate (15) is provided above the support truss. Multiple tracks are provided on the upper surface of the support truss. A traction component (13) is installed at the front of the base (17). The traction component (13) is fixedly connected to the hydraulic support column (14) in the working face. The traction component (13) can extend and retract in steps. The traction component (13) moves together with the traveling mechanism (1) as the hydraulic support column (14) moves. A sealing component (16) is installed at the front end of the base (17). The structure of the sealed component (16) includes a compressed air pipe (161), the inlet end of which is connected to the mine compressed air system and is equipped with an electrically controlled valve (162), and the outlet end of which is connected to an airbag (163). The structure of the extraction mechanism (2) includes an extraction main pipe (21) and a goaf inspection component (23). The outlet end of the extraction main pipe (21) is connected to the extraction pipeline in the roadway. Multiple extraction branch pipes (22) are installed on the extraction main pipe (21). Each extraction branch pipe (22) is equipped with a goaf extraction component (24). Each goaf extraction component (24) includes an air suction head (241), a guide motor (242), and an electric control valve (243). The air suction head (241) is located at the end of the extraction branch pipe (22) and is fixed to the end of the drive shaft of the guide motor (242). The air suction head (241) is connected to the electric control valve (243) through the guide motor (242). The electric control valve (243) is located in the extraction branch pipe (22) near the extraction pipeline. The goaf inspection component (23) includes a multi-parameter inspection instrument (231), a three-dimensional laser scanner (232), and a three-dimensional rotating camera (233). Multiple guide rails are installed on the support truss below the top support plate (15). The multi-parameter inspection instrument (231), the three-dimensional laser scanner (232), and the three-dimensional rotating camera (233) are respectively moved and set on their respective guide rails. The structure of the control mechanism (3) includes an explosion-proof box (37), inside which is installed a power adapter and a PLC. The PLC is equipped with an interactive interface and a switch. The PLC in the explosion-proof box (37) is connected to the information acquisition unit (31), the movement control unit (32), and the extraction control unit (33) via network cable (34). The power adapter in the explosion-proof box (37) is electrically connected to the information acquisition unit (31), the movement control unit (32), and the extraction control unit (33) via power cord (35). The power adapter in the explosion-proof box (37) is connected to the electrical cabinet (38) via power cord (35). The switch of the PLC is connected to the industrial ring network switch (4) via communication optical cable (36).

2. A method for extracting gas from the upper corner of a coal mining face, utilizing the gas extraction system for the upper corner of a coal mining face as described in claim 1, characterized in that... Follow these steps: Step 1: Determine the extraction parameters for the goaf in the coal mining face. Employing a comprehensive approach combining numerical simulation, similarity simulation, theoretical analysis, and engineering experiments, while considering both mine fire prevention and extinguishing requirements and the need for gas control in the upper corner, the specific process is as follows: Numerical simulation: Based on the geological conditions and mining parameters of the goaf, a three-dimensional flow field model is established to simulate the gas migration law under different negative pressures and extraction ranges, and to analyze the gas concentration distribution, flow velocity and air leakage intensity. Similarity simulation: A 1:50 physical model was built to simulate the collapse morphology and gas seepage characteristics of the goaf. The location of the extraction port and the negative pressure value were changed to observe the relationship between gas extraction efficiency and the oxidation and heating rate of residual coal. Theoretical analysis: Based on the gas migration equation and the coal spontaneous combustion kinetics theory, the critical extraction negative pressure is calculated, and the minimum negative pressure, maximum negative pressure, and extraction range are obtained. Engineering experiment: Select typical areas on site for trial extraction, deploy sensors to monitor gas concentration, negative pressure and oxygen content, compare extraction efficiency and fire prevention and extinguishing effect under different parameters, and determine the parameters; Finally, the extraction negative pressure and extraction range were determined. The extraction negative pressure includes low-gas areas to avoid excessive air extraction, high-gas areas to improve extraction efficiency, and near-spontaneous combustion risk areas to control air leakage. The extraction range includes gas accumulation areas along the strike, areas along the dip to avoid the main ventilation field, and areas along the vertical direction to avoid blockage by falling objects in the goaf. Step 2: Install the sampling system on site; Step 3: Start each electrical component, unfold the traveling mechanism (1), conduct inspections and collect relevant data and image information; Step 4: The control mechanism (3) completes information collection and processing, and obtains the analysis results. The specific process is as follows: the goaf inspection component (23) transmits the real-time collected data and image information to the control mechanism (3) via the network cable (34). The information acquisition unit (31) in the control mechanism (3) records all the information and analyzes and calculates it. Based on the latest information of the goaf collected, the information acquisition unit (31) completes a three-dimensional model of the current monitoring goaf internal situation. Step 5: The control mechanism (3) issues relevant action commands based on the analysis results, the traveling mechanism (1) completes the adjustment of the extraction position, and the extraction mechanism (2) completes the gas extraction of the current area. The specific process is as follows: Adjusting the extraction position: First, the travel control unit (32) controls the travel mechanism (1) to move. The travel control unit (32) receives the coordinates sent by the information acquisition unit (31). The travel control unit (32) sends a command to the traction component (13) to control the traction component (13) to extend and retract, driving the base (17) to move synchronously with the hydraulic support (14). Then, a command is sent to the support column (12) to make the four support columns (12) rise synchronously, raising the top support plate (15) close to the top plate of the goaf. Protective extraction space: Based on the height of the goaf, issue an unfolding command to the top support plate (15) to control its unfolding angle; To seal the goaf: send an opening command to the electrically controlled valve 1 (162) of the sealing component (16) to control the compressed air pipe (161) to inflate the airbag (163), so that the airbag (163) expands and fits against the rock wall of the goaf; Secondly, the extraction control unit (33) locates the extraction target area: the extraction control unit (33) receives the three-dimensional coordinates of the gas enrichment area generated by the information acquisition unit (31), and the extraction control unit (33) sends rotation and / or extension commands to the guide motor (242); adjust extraction parameters: the extraction control unit (33) sends an opening command to the second electric valve (243), adjusts the valve opening according to the gas concentration, and controls the extraction negative pressure; receives the opening signal from the second electric valve (243) and the position signal from the guide motor (242) in real time, and issues a correction command when there is a deviation; multi-area coordinated extraction: sends commands to the goaf extraction components (24) on different extraction branches (22), and adjusts the angle, extension length and opening of the guide motor (242) and the second electric valve (243) in each component differently to avoid mutual interference; Step 6: Once the gas concentration in the goaf has been reduced by extraction and meets safety standards, the extraction is confirmed to be complete, and the relevant components are removed.

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