Mine return air corner low-oxygen plugging, adjusting and guiding combined prevention and control system and method

Abstract

The invention provides a low-oxygen plugging, adjusting and guiding combined prevention and control system and method for a mine return air corner. The system comprises a wind shielding air bag, a pneumatic fan and an ejector. The wind shielding air bag firstly seals the corner, so that harmful gas source items are reduced, and a low-pressure-difference environment is created for subsequent links; the pneumatic fan rapidly increases the oxygen concentration of the corner at the air return corner and reduces the pressure difference, and dynamic balance of air pressure is achieved; and the ejector depends on a local flow field formed by the fan. The method comprises the steps of blocking a low-oxygen gas source at the air return corner of the working face, adjusting ventilation negative pressure by the pneumatic fan, guiding and exhausting harmful gas at the air return corner by the ejector and the like. Under the interaction of the steps, the real-time closed loop of air volume-pressure difference-concentration is realized, so that the oxygen concentration at the corner is continuously kept at a safe threshold value. The control system and method effectively improve the oxygen concentration of the air return corner of the working face, reduce the concentration of harmful gas gushing towards the working face in a goaf, and guarantee the oxygen supply safety of mine workers.

Description

Technical Field

[0001] This invention relates to the field of mining engineering, and in particular to a combined prevention and control system and method for low oxygen blockage in the corner of mine return air. Background Technology

[0002] Coal mining involves several hazards, such as coal and gas outbursts and rock bursts. While the probability of gas hazards is lower in low-gas mines, the release of harmful gases from the goaf still restricts and affects safe production. Specifically, when a large amount of residual coal remains in the goaf, air leakage is significant, and the working face advances slowly or adjacent coal seams experience severe air leakage, the coal seam is prone to oxidation. This leads to the release of harmful gases into the longwall face, ultimately causing hypoxia. In shallow-buried, multi-seam low-gas mines, the hypoxia problem is particularly severe, with corner concentrations sometimes falling below 18%, posing a significant threat to the lives of mine workers.

[0003] To ensure normal oxygen concentration, effective measures must be taken to prevent hypoxia and the formation of harmful gas leakage channels. Currently, although some progress has been made in controlling gas in the return air corners of working faces, such as gas extraction and grouting sealing, in-depth research on hypoxia remains insufficient. In recent years, the frequency of hypoxia in coal mine production sites has been increasing, but existing technologies for the prevention and control of harmful gases mainly focus on solving single problems, lacking systematic and comprehensive control methods. This often results in an inability to cope with the complex and ever-changing mine environment in practical applications; a comprehensive prevention and control plan for hypoxia has not yet been clearly defined, and efficient integrated prevention and control technologies remain scarce.

[0004] Therefore, there is an urgent need to develop a combined prevention and control system for low oxygen blockage in the corner of mine return air. Summary of the Invention

[0005] The purpose of this invention is to provide a combined prevention and control system for low oxygen blockage in the corner of mine return air, in order to solve the problems existing in the prior art.

[0006] The technical solution adopted to achieve the purpose of this invention is as follows: a combined prevention and control system for low oxygen blockage in the corner of mine return air, including a windproof airbag, a pneumatic fan and an ejector.

[0007] The windshield airbag is made of plastic-coated fabric. The airbag is filled with air or nitrogen. The airbag is suspended from the return air corner and the intake air corner by a hanging ring at the top.

[0008] The pneumatic fan is located at the intersection of the upper side and the roof of the return air tunnel. The pneumatic fan is hinged to the front end of the support beam and moves forward with the support. The jet direction of the pneumatic fan is inclined downwards. The pneumatic fan covers the return air corner area where oxygen easily accumulates, supplying air to the severely low-oxygen area in the return air corner.

[0009] The ejector system includes ejector I and ejector II. Ejector I is suspended from the end of the support frame. The air inlet of ejector I is connected to the downhole compressed air pipeline for air guidance and dispersion. Ejector II is located at the return air corner of the working face. After the pneumatic fan is installed, the ejector adjusts the airflow according to the gas concentration at the return air corner. It is activated when the oxygen concentration is too low or the concentration of harmful gases is too high to enhance the kinetic energy of the airflow and improve airflow distribution.

[0010] During operation, the windproof airbag first seals the corner, reducing the source of harmful gases and creating a low-pressure differential environment for subsequent stages. The pneumatic fan rapidly increases the oxygen concentration and reduces the pressure differential in the return air corner, achieving dynamic pressure balance. The ejector, relying on the local flow field created by the fan, directionally extracts residual low-oxygen gases to the main return air duct with minimal ejection work, avoiding secondary diffusion.

[0011] Furthermore, the inflation pressure of the windproof airbag is 0.3–0.5 MPa to maintain a semi-rigid, sealed shape. The windproof airbag has a compressible skirt at the contact point between the airbag body and the tunnel roof and walls to achieve wall-mounted leak sealing.

[0012] Furthermore, the pneumatic fan is connected to the top beam of the support frame via a chain hinge.

[0013] Furthermore, the air inlet of the pneumatic fan is equipped with a telescopic steel pipe. The installation reference point of the telescopic steel pipe is located at the end of the hydraulic support top beam. The telescopic steel pipe extends into the oxygen-deficient and gas-rich area at the boundary of the goaf. The extension depth of the telescopic steel pipe is calibrated and fixed according to the location of the lowest oxygen concentration area at the return air corner measured on-site at the working face. The pipe wall of the telescopic steel pipe is provided with pressure equalization holes, and a filter screen is installed at the inlet to prevent coal dust from being sucked in. During installation, the telescopic steel pipe is pushed to the set position by means of the support tail beam slide rail and hand-cranked winch.

[0014] Furthermore, the outlet end of ejector I and the inlet end of ejector II are equipped with telescopic ducts with rigid frames. The rigid duct, connected in series with the outlet end of ejector II, ejects low-oxygen gas from the return air corner to the fixed exhaust area.

[0015] Furthermore, the air outlet of ejector II is located around the coal wall of the return airway. The air inlet of ejector II is higher than the air outlet.

[0016] Furthermore, the ejector airflow is calculated based on the airflow requirement at the return air corner. The ejector airflow should ensure an additional 500 m³ / h.3 Based on the airflow characteristics of the working face, determine the airflow volume and inlet pressure of the ejector according to the airflow volume of / h.

[0017]

[0018] Q min Q is the minimum airflow that can be achieved through the windshield airbag. lack This refers to the air leakage in the goaf, estimated using the pressure difference / tracer gas attenuation method before and after the windbreak airbag. The oxygen concentration in the fresh airflow is approximately 20.9%. The target oxygen concentration at the return air corner. This represents the oxygen concentration of the gas leaking into the goaf.

[0019] This invention also discloses a combined method for guiding and regulating low-oxygen blockage at the corner of mine return air according to the above system, comprising the following steps:

[0020] 1) Analyze the atmospheric pressure evolution patterns at the surface and return air corners of the working face, and investigate on-site ventilation parameters.

[0021] 2) Construct a combined prevention and control system for low oxygen blockage in the mine return air corner as described in claim 1 at the working face. Step 2) includes the following sub-steps, which may be performed in any order or simultaneously:

[0022] 2.1) Seal leaks to prevent air leakage in the goaf. Based on the basic parameters of the site survey in Layout 1), seal the air leakage channels and strengthen the airtightness of the goaf.

[0023] 2.2) Adjusting ventilation negative pressure: A pneumatic fan is suspended in the return air corner to force fresh air into the corner, forming a local positive pressure curtain to counteract the low-pressure airflow surging outward from the goaf. This keeps the pressure difference between the working face and the goaf at a low level, achieving continuous, adjustable, and mobile balance of ventilation negative pressure.

[0024] 2.3) Guiding Harmful Gases in the Return Air Corner. After the baffle airbag and pneumatic fan complete the sealing and pressure regulation, an ejector is suspended in the core area of ​​the vortex in the return air corner. The inlet faces the area with the lowest oxygen concentration and the highest CO manifestation, and the outlet connects to the main exhaust port of the return airway through a rigid air duct. The ejector forms a high-speed jet around the nozzle, entraining and carrying away low-oxygen gas, continuously maintaining a local slight negative pressure to prevent harmful gases from spreading to the working area. The entrainment air volume and suspension angle are adjusted in real time according to the advancement of the working face and sensor feedback. The entrainment air volume and suspension angle are collected by oxygen and wind speed sensors arranged at the inlet and outlet of ejector II. The sensor data is connected to the working face substation, and after comparison by the downhole control host, the opening of the compressed air valve is automatically adjusted and the suspension push rod is driven to achieve closed-loop feedback of air volume and angle, ensuring that the oxygen concentration in the corner is stable above the safe level.

[0025] 3) During the working face advance, monitor the changes in oxygen concentration after each sub-step in step 2) to determine the process parameters under different measures.

[0026] Further, in step 1), an atmospheric pressure sensor is installed at the wellhead to obtain the variation pattern of surface atmospheric pressure. An atmospheric pressure monitoring point is set up by burying a bundle of tubes at the return air corner of the working face to monitor the atmospheric pressure variation data at the return air corner. The evolution pattern of atmospheric pressure at the surface and the return air corner of the working face is analyzed to obtain the influence of surface atmospheric pressure on the atmospheric pressure at the return air corner of the working face. A differential pressure sensor is installed at the working face to monitor the pressure difference between the goaf and the working face, so as to adjust the air pressure subsequently.

[0027] Furthermore, during normal mining operations in the low-oxygen working face, windproof airbags are used to seal leaks at the corners of both ends of the support to prevent air leakage in the goaf.

[0028] The technical effects of this invention are undeniable: it proposes a combined prevention and control system for low-oxygen blockage in the return air corner of a mine. The windproof airbags prevent harmful gases from the goaf from directly accumulating in the return air corner; the ejector effectively increases the oxygen concentration in the return air corner, ensuring safe production at the working face; by suspending the windproof airbags and combining them with the airflow regulation of the pneumatic fan and the negative pressure extraction effect of the ejector, the fresh airflow in the return air corner can be significantly improved, increasing the oxygen concentration in this area, thereby effectively reducing the concentration of harmful gases and improving the mine working environment. The operation sequence of the integrated prevention and control system is as follows: the windproof airbags first seal the corner, reducing the source of harmful gases and creating a low-pressure differential environment for subsequent stages; the pneumatic fan rapidly increases the oxygen concentration and reduces the pressure differential in the return air corner, achieving dynamic pressure balance; the ejector, relying on the local flow field formed by the fan, uses minimal extraction work to directionally extract residual low-oxygen gases to the main return air duct, avoiding secondary diffusion. The synergistic effect of these three stages ensures that the oxygen concentration in the corner remains at a safe threshold. Attached Figure Description

[0029] Figure 1 A schematic diagram of a combined prevention and control system for low oxygen blockage in the corner of a mine return airway;

[0030] Figure 2 This is a schematic diagram of the corner of the airbag sealing and blocking system.

[0031] Figure 3 To dilute and regulate harmful gases at the return air corner using a pneumatic fan;

[0032] Figure 4 Schematic diagram of the positive pressure working air guide for ejector I to dilute harmful gases in the return air corner;

[0033] Figure 5 Schematic diagram of ejector II for venting harmful gases;

[0034] Figure 6 Schematic diagram of the ejector; Figure 6 a is a schematic diagram of the ejector's appearance; Figure 6 b is a diagram of the ejector's on-site installation.

[0035] In the diagram: 1. Windshield airbag; 2. Pneumatic fan; 3. Ejector I; 4. Ejector II. Detailed Implementation

[0036] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0037] Example 1:

[0038] See Figures 1-6 This embodiment provides a combined prevention and control system for low oxygen blockage in the corner of mine return air, including a windproof airbag 1, a pneumatic fan 2, and an ejector.

[0039] The windshield airbag 1 is made of plastic-coated fabric. The windshield airbag 1 is filled with air or nitrogen. The windshield airbag 1 is suspended from the return air corner and the air intake corner by a hanging ring set at the top.

[0040] The pneumatic fan 2 is located at the intersection of the upper side and the roof of the return air tunnel. The pneumatic fan 2 is hinged to the front end of the support beam and moves forward with the support. The jet direction of the pneumatic fan 2 is inclined downwards. The pneumatic fan 2 covers the return air corner area where oxygen easily accumulates, supplying air to the severely low-oxygen area in the return air corner.

[0041] The ejector system includes ejector I3 and ejector II4. Ejector I3 is suspended at the end of the support frame. The air inlet of ejector I3 is connected to the downhole compressed air pipeline for air guidance and dispersion. Ejector II4 is located at the return air corner of the working face. After the pneumatic fan 2 is installed, the ejector adjusts the airflow according to the gas concentration at the return air corner. It is activated when the oxygen concentration is too low or the concentration of harmful gases is too high to enhance the kinetic energy of the airflow and improve airflow distribution.

[0042] During operation, the windproof airbag 1 first seals the corner, reducing the source of harmful gases and creating a low-pressure differential environment for subsequent processes. The pneumatic fan 2 rapidly increases the oxygen concentration and reduces the pressure differential in the return air corner, achieving dynamic balance of wind pressure. The ejector, relying on the local flow field created by the fan, directionally extracts residual low-oxygen gas to the main return air duct with minimal ejection work, avoiding secondary diffusion.

[0043] This embodiment no longer employs a passive, single-method approach, but rather actively controls airflow and pressure through the orderly coordination of three devices, fundamentally improving air quality in the return air corner and continuously maintaining oxygen concentration above the safe threshold. The windshield airbag, pneumatic fan, and ejector do not operate independently, but follow a clear sequence and collaborative logic.

[0044] Example 2:

[0045] The main content of this embodiment is the same as that of Embodiment 1, wherein, see [link / reference]. Figure 2 The airbag 1 is inflated at a pressure of 0.3–0.5 MPa to maintain a semi-rigid, sealed shape. The airbag 1 has a compressible skirt at the point where it contacts the tunnel roof and walls to achieve wall-mounted sealing.

[0046] Example 3:

[0047] The main content of this embodiment is the same as that of embodiment 1 or 2, wherein, see [link / reference]. Figure 3 The pneumatic fan 2 is connected to the top beam of the support via a chain hinge. A telescopic steel pipe is installed at the air inlet of the pneumatic fan 2. The installation reference point of the telescopic steel pipe is located at the end of the hydraulic support top beam. The telescopic steel pipe extends into the oxygen-deficient and gas-rich area at the boundary of the goaf. The extension depth of the telescopic steel pipe is calibrated and fixed based on the location of the lowest oxygen concentration area at the return air corner measured on-site at the working face. The pipe wall of the telescopic steel pipe has pressure equalization holes, and a filter screen is installed at the inlet to prevent coal dust from being sucked in. During installation, the telescopic steel pipe is pushed to the set position using the support tail beam slide rail and a hand-cranked winch.

[0048] Example 4:

[0049] The main content of this embodiment is the same as any one of embodiments 1 to 3, wherein, see [link to embodiment 1]. Figures 4-6 The ejector I3 and the ejector II4 are equipped with telescopic ducts with rigid frames. The ejector II4, with its air outlet end connected in series with the rigid duct, ejects low-oxygen gas from the return air corner to the fixed exhaust area.

[0050] The air outlet of ejector II4 is located around the coal wall of the return airway. The air inlet of ejector II4 is higher than the air outlet.

[0051] The ejector airflow is calculated based on the airflow requirement at the return air corner. The ejector airflow should ensure an additional 500m³ / h. 3 Based on the airflow characteristics of the working face, determine the airflow volume and inlet pressure of the ejector according to the airflow volume of / h.

[0052]

[0053] Q minQ is the minimum airflow that can be achieved through the windshield airbag 1. lack This is the air leakage in the goaf, estimated using the pressure difference / tracer gas attenuation method before and after the windbreak airbag 1. The oxygen concentration in the fresh airflow is approximately 20.9%. The target oxygen concentration at the return air corner. This represents the oxygen concentration of the gas leaking into the goaf.

[0054] Example 5:

[0055] This embodiment provides a combined method for guiding and regulating low-oxygen blockage in the mine return air corner according to any one of embodiments 1 to 4, including the following steps:

[0056] 1) Analyze the atmospheric pressure evolution patterns at the surface and the return air corner of the working face, and investigate on-site ventilation parameters. Install atmospheric pressure sensors at the wellhead to obtain the surface atmospheric pressure variation patterns. Install bundled tubes at the return air corner of the working face to set up atmospheric pressure monitoring points and monitor atmospheric pressure changes at the return air corner. Analyze the atmospheric pressure evolution patterns at the surface and the return air corner of the working face to obtain the influence of surface atmospheric pressure on the atmospheric pressure at the return air corner of the working face. Install differential pressure sensors at the working face to monitor the pressure difference between the goaf and the working face for subsequent air pressure adjustment.

[0057] 2) Construct a combined prevention and control system for low oxygen blockage in the mine return air corner as described in claim 1 at the working face. Step 2) includes the following sub-steps, which may be performed in any order or simultaneously:

[0058] 2.1) Seal leaks to prevent air leakage in the goaf. Based on the basic parameters of the site survey in Layout 1), seal the air leakage channels and strengthen the airtightness of the goaf.

[0059] 2.2) Adjusting the negative pressure of ventilation: Hang pneumatic fans 2 in the return air corner to force fresh air into the corner, forming a local positive pressure curtain to counteract the low-pressure airflow surging outward from the goaf. Control the pressure difference between the working face and the goaf at a low level to achieve continuous, adjustable, and mobile balance of the negative pressure of ventilation.

[0060] 2.3) Guiding Harmful Gases in the Return Air Corner. After the windproof airbag 1 and pneumatic fan 2 complete the sealing and pressure regulation, an ejector is suspended in the core area of ​​the vortex in the return air corner. The inlet faces the area with the lowest oxygen concentration and the highest CO manifestation, and the outlet is connected to the main exhaust port of the return airway through a rigid air duct. The ejector forms a high-speed jet around the nozzle, entraining and carrying away low-oxygen gas, continuously maintaining a local slight negative pressure to prevent harmful gases from spreading to the working area. The entrainment air volume and suspension angle are adjusted in real time according to the advancement of the working face and sensor feedback. The entrainment air volume and suspension angle are collected by oxygen and wind speed sensors arranged at the inlet and outlet of ejector II. The sensor data is connected to the working face substation, and after comparison by the underground control host, the opening of the compressed air valve is automatically adjusted and the suspension push rod is driven to achieve closed-loop feedback of air volume and angle, ensuring that the oxygen concentration in the corner is stable above the safe level.

[0061] 3) During the working face advance, monitor the changes in oxygen concentration after each sub-step in step 2) to determine the process parameters under different measures.

[0062] Example 6:

[0063] The main content of this embodiment is the same as that of embodiment 5. In this embodiment, during the normal mining period of the low-oxygen working face, the windproof airbag 1 is used to seal the leaks at the corners of both ends of the support to prevent air leakage in the goaf.

[0064] Example 7:

[0065] This embodiment is similar in main content to Embodiment 5, except that monitoring points are set up at locations where low oxygen problems frequently occur in the return air corner of the low-oxygen working face to monitor the effectiveness of harmful gas control and achieve a systematic prevention, control, monitoring, and early warning system. The monitoring point range includes a portion of the return airway, the return air corner area, and the area near the ejector. The horizontal and vertical spacing between each monitoring point is 1 meter. A mixed gas test is conducted continuously for five minutes using a handheld multi-functional portable gas tester, and the results are recorded. The concentration of harmful gases is measured on-site, including oxygen (O2), carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4). Within 7 days after the implementation of the combined prevention and control technology of harmful gas outburst interception and fresh airflow guidance, measurements should be taken once every other shift, three shifts a day; after 7 days, measurements should be taken once every other day.

Claims

1. A combined prevention and control system for low oxygen blockage in the corner of mine return air, characterized in that: Includes a windshield airbag (1), a pneumatic fan (2), and an ejector; The windshield airbag (1) is made of plastic-coated cloth; the windshield airbag (1) is filled with air or nitrogen; the windshield airbag (1) is suspended at the return air corner and the air inlet corner; The pneumatic fan (2) is located at the intersection of the upper side and the top plate of the return air tunnel; the pneumatic fan (2) is hinged to the front end of the support top beam and moves forward with the support; the jet direction of the pneumatic fan (2) is inclined downward; the pneumatic fan (2) covers the return air corner area where it is easy to accumulate air and supplies air to the severely low oxygen area at the return air corner. The ejector includes ejector I (3) and ejector II (4); ejector I (3) is suspended at the end of the support; the air inlet of ejector I (3) is connected to the downhole compressed air pipeline for air guidance and dispersion; ejector II (4) is arranged in the return air corner of the working face; after the pneumatic fan (2) is installed, the ejector adjusts the air volume according to the gas concentration in the return air corner, and starts when the oxygen concentration is too low or the concentration of harmful gas is too high, so as to enhance the kinetic energy of the airflow and improve the airflow distribution; During operation, the windproof airbag (1) first seals the corner, reducing the source of harmful gases and creating a low pressure difference environment for subsequent stages; the pneumatic fan (2) quickly increases the oxygen concentration in the corner and reduces the pressure difference, achieving dynamic balance of wind pressure; the ejector relies on the local flow field formed by the fan to directionally exhaust the residual low oxygen gas to the main return air duct with minimal ejection work, avoiding secondary diffusion.

2. The mine return air corner low oxygen blockage guidance and prevention system according to claim 1, characterized in that: The inflation pressure of the windproof airbag (1) is 0.3 to 0.5 MPa; the windproof airbag (1) is provided with a compressible skirt at the position where the airbag body contacts the roof and sidewall of the roadway.

3. The mine return air corner low oxygen blockage guidance and prevention system according to claim 1, characterized in that: The pneumatic fan (2) is connected to the top beam of the support by means of a hanging chain hinge.

4. The mine return air corner low oxygen blockage guidance and prevention system according to claim 1, characterized in that: The air inlet of the pneumatic fan (2) is equipped with a telescopic steel pipe; the installation reference point of the telescopic steel pipe is located at the end of the top beam of the hydraulic support; the telescopic steel pipe extends into the oxygen-deficient and gas-rich area at the boundary of the goaf; the extension depth of the telescopic steel pipe is calibrated and fixed according to the location of the lowest oxygen concentration area at the return air corner measured on-site at the working face; the pipe wall of the telescopic steel pipe is provided with pressure equalization holes, and a filter screen is installed at the inlet to prevent coal dust from being sucked in; during installation, the telescopic steel pipe is pushed to the set position by means of the support tail beam slide rail and hand winch.

5. The mine return air corner low oxygen blockage guidance and prevention system according to claim 1, characterized in that: The air outlet of ejector I (3) and the air inlet of ejector II (4) are provided with telescopic air ducts with rigid frames; the air outlet of ejector II (4) is connected in series with the rigid air duct to eject low oxygen gas from the return air corner to the fixed exhaust area.

6. The mine return air corner low oxygen blockage guidance and prevention system according to claim 1, characterized in that: The air outlet of ejector II (4) is located around the coal wall of the return airway; the air inlet of ejector II (4) is higher than the air outlet.

7. The mine return air corner low oxygen blockage guidance and prevention system according to claim 1, characterized in that: The ejector airflow is calculated based on the airflow requirement at the return air corner. The ejector airflow should ensure an additional 500 m³ / h. 3 The air volume is determined by the airflow characteristics of the working face, and the air volume and inlet pressure of the ejector are determined accordingly. Q min Q is the minimum airflow that can be achieved through the windshield airbag (1). lack The air leakage in the goaf is estimated by the pressure difference / tracer gas attenuation method before and after the windproof airbag (1). The oxygen concentration in the fresh airflow is approximately 20.9%. The target oxygen concentration at the return air corner. This represents the oxygen concentration of the gas leaking into the goaf.

8. A combined method for guiding and regulating low-oxygen blockage at the corner of a mine return airway according to any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Analyze the atmospheric pressure evolution patterns at the surface and return air corners of the working face, and investigate on-site ventilation parameters; 2) Construct a mine return air corner low oxygen blockage guidance and prevention system as described in claim 1 at the working face; step 2) includes the following sub-steps that can be performed in any order or simultaneously: 2.1) Prevent air leakage in the goaf by sealing leaks; based on the basic parameters of the site surveyed in Layout 1), seal the air leakage channels and strengthen the airtightness of the goaf. 2.2) Adjusting ventilation negative pressure: Hang pneumatic fans (2) in the return air corner to force fresh air into the corner, forming a local positive pressure curtain to counteract the low-pressure airflow surging out of the goaf; keep the pressure difference between the working face and the goaf at a low level to achieve continuous, adjustable and mobile balance of ventilation negative pressure; 2.3) Guide harmful gases in the return air corner; After the windproof airbag (1) and pneumatic fan (2) complete the sealing-pressure regulation, hang an ejector in the core area of ​​the vortex in the return air corner. The inlet faces the area with the lowest oxygen concentration and the highest CO manifestation, and the outlet is connected to the main exhaust port of the return airway through a rigid air duct. The ejector forms a high-speed jet around the nozzle, which sucks up and carries away low-oxygen gas, continuously maintains a local slight negative pressure, prevents harmful gases from spreading to the work area, and the suction air volume and hanging angle are adjusted in real time with the advancement of the working face and the feedback of the sensor; to ensure that the oxygen concentration in the corner is stable above the safe level. 3) During the working face advance, monitor the changes in oxygen concentration after each sub-step in step 2) to determine the process parameters under different measures.

9. A combined method for guiding and regulating low-oxygen blockage at the corner of a mine return airway according to claim 8, characterized in that: In step 1), an atmospheric pressure sensor is installed at the wellhead to obtain the variation pattern of surface atmospheric pressure; an atmospheric pressure monitoring point is set up by burying a bundle tube at the return air corner of the working face to monitor the atmospheric pressure variation data at the return air corner; the evolution pattern of atmospheric pressure at the surface and the return air corner of the working face is analyzed to obtain the influence of surface atmospheric pressure on the atmospheric pressure at the return air corner of the working face; a differential pressure sensor is installed at the working face to monitor the pressure difference between the goaf and the working face, so as to adjust the air pressure in the future.

10. A combined method for guiding and regulating low-oxygen blockage at the corner of mine return air according to claim 8, characterized in that: During normal mining in the low-oxygen working face, windproof airbags (1) are used to seal leaks at the corners of both ends of the support to prevent air leakage in the goaf.

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