Device and method for plugging air leakage by fixed-point foam injection in goaf

Abstract

The present invention relates to a device and method for plugging air leakage in a goaf by injecting foam at a fixed point. The device comprises two foam generating devices and a foam injection pipe. The two foam generating devices are respectively arranged in an air inlet tunnel and a return air tunnel, and are connected to an advance support hydraulic support in the air inlet tunnel and the return air tunnel. The advance support hydraulic support can drive the foam generating device to move forward. Coal wall pipe grooves extending in a front-to-back direction are provided on the protective coal pillars on the left and right sides of the goaf. Foam injection pipes are laid in the coal wall pipe grooves. The output end of the foam generating device is connected to the end of the foam injection pipe away from the goaf. The foam injection pipe is provided with multiple foam release ports at equal intervals along the length direction. The foam injection pipe can automatically close the old channel and open a new injection point as the overburden collapses. The device for plugging air leakage lays the foam injection pipe on the coal wall of the protective coal pillar, which has low construction cost and will not be crushed by falling rocks. At the same time, the foam released by the foam injection pipe can effectively block the air leakage channel in the triangular area.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine goaf area air leakage blocking devices, in particular to a goaf area foam fixed-point injection air leakage blocking device and an air leakage blocking method. Background Art

[0002] See also Figure 1 During the mining process of the coal seam working face, the mining action often produces cracks connected to the adjacent working face, the upper working face, and even the surface, which leads to air leakage in goaf 2, increases the ventilation demand of the working face, and may lead to a low-oxygen environment, increasing the risk of spontaneous combustion of the coal in goaf 2. The coal in goaf 2 usually exists in the form of broken piles. Under the conditions of continuous leakage and oxygen supply, heat continues to accumulate, which can easily cause spontaneous combustion, seriously threatening the safe production of the mine and the lives and health of workers. In addition, with the gradual collapse and compaction of the overlying rock strata, the air leakage channels in goaf 2 are mainly concentrated in the triangular area near the protective coal pillar 5.

[0003] The existing coal mine goaf air leakage plugging device includes an isolation wall 6, a grouting pipe 7 and a nitrogen injection pipe 8. The air leakage plugging method based on the existing coal mine goaf air leakage plugging device includes: step S1, before the end of mining, according to the three-zone division standard of the goaf spontaneous combustion zone, the coal seam during the end of mining-stop withdrawal period is divided into an isolation wall construction area, a grouting area and a nitrogen injection area for fire prevention and extinguishing in the end of mining; step S2, pre-buried grouting pipes 7 and nitrogen injection pipes 8 in the bottom plates of the air intake tunnel 3 and the return air tunnel 4; step S3, constructed an isolation wall 6 in the isolation wall construction area; step S4, in the process of advancing the coal mining working face, grouting is injected into the goaf through the grouting pipe 7, and nitrogen is injected into the goaf 2 through the nitrogen injection pipe 8, thereby sealing and inerting the gas in the goaf 2 to prevent the residual coal in the goaf 2 from spontaneous combustion. The defects and deficiencies of the existing coal mine goaf air leakage plugging devices and methods are as follows: (1) the grouting pipes 7 and nitrogen injection pipes 8 are pre-buried in the tunnel floor, but the grouting effect is poor and the air leakage channel in the triangular area cannot be effectively blocked; (2) as the overlying rock layer in the goaf gradually collapses, the grouting pipes 7 and nitrogen injection pipes 8 pre-buried in the tunnel floor are at risk of being crushed; (3) the buried pipe injection method is to place the pipeline on the tunnel floor, and as the coal mining working face advances, the pipeline is gradually pressed into the goaf, but manual labor is required to continuously place the pipeline, and there are overlapping areas between the pipelines, which leads to a lot of waste of consumables and high labor costs; (4) in the process of rapid advancement of the coal mining working face, how to achieve the synchronous follow-up of the goaf 2 air leakage plugging still faces many technical difficulties.

[0004] Therefore, there is an urgent need to provide a goaf area foam fixed-point injection plugging air leakage device and a plugging air leakage method with low cost and good plugging effect. Summary of the Invention

[0005] (1) Technical issues to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a device and method for plugging air leakage by fixed-point foam injection in goafs, which solves the technical problems of the existing device for plugging air leakage in goafs, such as complex technology, high construction cost, and easy damage by overlying rock strata.

[0007] (2) Technical solution

[0008] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, an embodiment of the present invention provides a device for plugging air leakage in a goaf by injecting foam at a fixed point, comprising two foam generating devices and a foam injection pipe;

[0010] The two foam generating devices are respectively arranged in the air intake and return air tunnels of the coal mining face and connected to the advance support hydraulic supports in the air intake and return air tunnels. The advance support hydraulic supports can drive the foam generating devices to move forward.

[0011] Coal wall pipe grooves extending in the front-to-back direction are opened on the protective coal pillars on the left and right sides of the goaf. Foam injection pipes are laid in the coal wall pipe grooves. The output end of the foam generating device is connected to the end of the foam injection pipe away from the goaf. Multiple foam release ports are arranged on the foam injection pipe at equal intervals along the length direction.

[0012] Optionally, the foam generating device includes a carrier vehicle, a gas-liquid mixing mechanism, a foam mixing mechanism, a foam storage tank, and a foaming agent pump;

[0013] The front end of the advance support hydraulic support is hinged to the rear end of the carrying vehicle. The carrying vehicle is installed with a gas-liquid mixing mechanism, a foam mixing mechanism, a foam storage tank and a foam agent pump. The gas-liquid mixing mechanism has an air inlet end, a liquid inlet end and a mixing output end connected to the air inlet end and the liquid inlet end. The mixing output end of the gas-liquid mixing mechanism is connected to the first input end of the foam mixing mechanism. The foam storage tank is connected to the second input end of the foam mixing mechanism through the foam agent pump. The foam output end of the foam mixing mechanism is connected to the foam injection pipe.

[0014] Optionally, a metal mesh is provided at the connection between the foam output end of the foam mixing mechanism and the foam injection pipe.

[0015] Optionally, the advance support hydraulic support and the carrying vehicle are hinged via a flexible connection device.

[0016] Optionally, a tunnel compressed air pipeline and a tunnel water supply pipeline are provided on the advance support hydraulic support. The tunnel compressed air pipeline is connected to the air inlet end of the gas-liquid mixing mechanism to supply inert gas to the gas-liquid mixing mechanism, and the tunnel water supply pipeline is connected to the liquid inlet end of the gas-liquid mixing mechanism.

[0017] Optionally, the foam injection pipe has a plurality of sub-pipelines connected in sequence, and adjacent sub-pipelines are detachably connected via quick connectors.

[0018] Optionally, each foam release port is provided with an automatic opening assembly, which includes a casing, a first bevel gear, a second bevel gear, a throttle plate and a pressure plate;

[0019] The outer wall of the foam injection pipe is provided with a casing at the foam release port, and the interior of the casing is used for positioning and supporting bevel gear 1 and bevel gear 2, and bevel gear 1 is meshed with bevel gear 2;

[0020] One end of the pressure plate is fixedly connected to the rotating shaft of bevel gear one, and the other end of the pressure plate extends into the goaf. The throttle plate is located in the foam injection pipe and is fixedly connected to the rotating shaft of bevel gear two, wherein the throttle plate can rotate between a closed position and a throttling position. In the closed position, the throttle plate closes the corresponding foam release port; and in the throttling position, the throttle plate opens the corresponding foam release port and prevents the foam from moving rearward along the foam injection pipe.

[0021] In a second aspect, an embodiment of the present invention provides a method for plugging air leakage using the above-mentioned goaf foam fixed-point injection plugging air leakage device, the method comprising the following steps: S1, trenching construction, including: excavating coal wall pipe trenches extending in the front-to-back direction on the protective coal pillars on the left and right sides of the goaf; laying foam injection pipes in the coal wall pipe trenches;

[0022] S2. Air leakage detection to determine the location of the air leakage channel and the amount of air leakage;

[0023] S3. Determine the foam injection location based on the air leakage detection result in step S2: If there is an air leakage channel in the triangular area on one side of the air inlet roadway, the foam generating device in the air inlet roadway proceeds to step S4; if there is an air leakage channel in the triangular area on one side of the return air roadway, the foam generating device in the return air roadway proceeds to step S4; if there are air leakage channels in the triangular areas on both sides of the goaf, the foam generating devices in both the air inlet roadway and the return air roadway proceed to step S4;

[0024] S4, foam preparation, including: connecting the foam generating device to the advance support hydraulic support; connecting the output end of the foam generating device to the foam injection pipe in a one-to-one correspondence; and preparing and generating foam by the foam generating device;

[0025] S5. Foam injection: The foam generating device delivers the prepared foam to the foam injection pipe. The foam moves toward the rear side along the foam injection pipe and is released into the triangular area through the foam release port to block the air leakage channel in the triangular area.

[0026] Optionally, the air leakage plugging method further includes:

[0027] S6, synchronous follow-up, including: disconnecting the foam generating device and the foam injection pipe, advancing the coal mining face forward, and the advanced support hydraulic support synchronously drives the foam generating device forward, repeating steps S1-S5 until the coal mining operation is stopped

[0028] Optionally, the trenching construction position of the coal wall pipe trench is 1-2m away from the tunnel floor.

[0029] (3) Beneficial effects

[0030] The beneficial effects of the present invention are as follows: the goaf area fixed-point foam injection and plugging air leakage device of the present invention comprises two foam generating devices and a foam injection pipe; the two foam generating devices are respectively arranged in the air inlet tunnel and the return air tunnel of the coal mining working face, and are connected to the advance support hydraulic supports in the air inlet tunnel and the return air tunnel, and the advance support hydraulic supports can drive the foam generating device to move forward; coal wall pipe grooves extending in the front-to-back direction are provided on the protective coal pillars on the left and right sides of the goaf, and foam injection pipes are laid in the coal wall pipe grooves, the output end of the foam generating device is connected to the end of the foam injection pipe away from the goaf, and the foam injection pipe is provided with a plurality of foam release ports at equal intervals along the length direction. When the foam generating device is working, Foam is generated and enters the goaf through the foam injection pipe on the protective coal pillar, thereby blocking the air leakage channel in the triangular area of ​​the protective coal pillar. Compared with the existing technology, firstly, the goaf foam fixed-point injection and air leakage blocking device lays the foam injection pipe on the protective coal pillar, and its on-site construction is simple and low-cost, and the foam injection pipe in the protective coal pillar will not be crushed when the overlying rock stratum falls; secondly, the foam injection pipe is closer to the triangular area of ​​the coal pillar, so the foam released by the foam injection pipe can effectively block the air leakage channel; finally, when the coal mining working face advances forward, the advanced support hydraulic support can drive the foam generating device to move forward, and the goaf air leakage blocking device can be synchronously followed up without manual operation.

[0031] The air leakage plugging method based on the goaf foam fixed-point injection plugging device of the present invention adopts the coal wall groove-cutting type foam fixed-point injection method. Compared with the adjacent tunnel and buried pipe injection methods, this method greatly reduces the cost and process difficulty and has higher feasibility. This method can not only significantly reduce the oxygen concentration in the goaf, but also effectively alleviate the low oxygen problem in the corners, while preventing coal spontaneous combustion, improving the safety of mining operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the layout structure of the isolation wall, grouting pipe and nitrogen injection pipe of the existing coal mine goaf area air leakage blocking device;

[0033] Figure 2 This is a top view of the goaf area fixed-point foam injection plugging air leakage device of the present invention when it is deployed on a coal mining face;

[0034] Figure 3 for Figure 2 A cross-sectional diagram of the goaf foam fixed-point injection plugging air leakage device in the goaf;

[0035] Figure 4 It is a schematic diagram of the connection structure between the foam generating device and the advanced support hydraulic support of the present invention;

[0036] Figure 5 This is a top view schematic diagram of the foam injection pipe of the present invention being laid in a protective coal pillar.

[0037] [Description of Reference Numerals]

[0038] 1: Area to be mined; 2: Goaf; 3: Air intake tunnel; 4: Return air tunnel; 5: Protective coal pillar; 6: Isolation wall; 7: Grouting pipe; 8: Nitrogen injection pipe; 9: Foam generating device; 10: Foam injection pipe; 11: Coal wall pipe groove; 12: Foam release port; 13: Advanced support hydraulic support; 14: Tunnel compressed air pipeline; 15: Tunnel water supply pipeline; 16: Flexible connection device; 17: Connecting tunnel; 18: Carrying vehicle; 19: Gas-liquid mixing mechanism; 20: Foam mixing mechanism; 21: Foam storage box; 22: Metal mesh; 23: Foam agent pump; 24: Bevel gear 1; 25: Bevel gear 2; 26: Throttle plate; 27: Pressure plate; 28: Limiting part; 29: Overburden. DETAILED DESCRIPTION

[0039] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below with reference to the accompanying drawings and through specific embodiments. Figure 2 It should be noted that, in this embodiment, the direction approaching the mining area 1 is "front", and the direction approaching the goaf 2 is "back", and the coal mining working face is always moving forward to mine the coal in the mining area 1.

[0040] Please refer to Figure 2 and Figure 3 , Figure 2 The diagram shows a top view of the goaf area fixed-point foam injection plugging device of this embodiment when it is deployed on a coal mining face. Figure 3 for Figure 2 A partial cross-sectional diagram of the goaf foam fixed-point injection plugging air leakage device in the goaf.

[0041] This embodiment provides a device for plugging air leakage in goaf by fixed-point foam injection, which includes two foam generating devices 9 and a foam injection pipe 10 .

[0042] Two foam generating devices 9 are respectively arranged in the air inlet tunnel 3 and the return air tunnel 4 of the coal mining face, and are connected to the advance support hydraulic supports 13 in the air inlet tunnel 3 and the return air tunnel 4. The advance support hydraulic supports 13 can drive the foam generating devices 9 to move forward;

[0043] The protective coal pillars 5 on the left and right sides of the goaf 2 are provided with coal wall pipe grooves 11 extending in the front-to-back direction. Foam injection pipes 10 are laid in the coal wall pipe grooves 11. The output end of the foam generating device 9 is connected to the end of the foam injection pipe 10 away from the goaf 2. The foam injection pipe 10 is provided with multiple foam release ports 12 at equal intervals along its length. Preferably, the interval between adjacent foam release ports 12 is 3 meters.

[0044] The goaf area fixed-point foam injection and air leakage plugging device of this embodiment is constructed by laying foam injection pipes 10 on the protective coal pillars 5 on the left and right sides of the goaf 2. When working, the foam generating device 9 generates foam, and the foam enters the goaf through the foam injection pipes 10 on the protective coal pillars 5, thereby blocking the air leakage channel at the triangular area of ​​the protective coal pillars 5. Compared with the existing coal mine goaf area air leakage plugging device, its on-site construction is simple and low-cost, and the overlying rock stratum 29 above the goaf 2 will not crush the foam injection pipe 10 when it falls; in addition, when the coal mining working face advances forward, the advance support hydraulic support 13 can drive the foam generating device 9 to move forward, and the goaf area air leakage plugging can be achieved synchronously without manual operation.

[0045] In this embodiment, the foam injection pipe 10 comprises multiple, sequentially connected sub-pipelines, each detachably connected via a quick-connect connector. This structure allows for the installation of additional sub-pipelines at the end of the foam injection pipe 10 away from the goaf 2 as the coal face advances, thereby increasing its length and facilitating its use.

[0046] See also Figure 4 , Figure 4 Schematic diagram showing the connection structure of the foam generating device and the advance support hydraulic support of this embodiment.

[0047] The foam generating device 9 of this embodiment includes a carrier vehicle 18 , a gas-liquid mixing mechanism 19 , a foam mixing mechanism 20 , a foam storage tank 21 and a foaming agent pump 23 .

[0048] The front end of the advance support hydraulic support 13 is hinged to the rear end of the carrying vehicle 18. The carrying vehicle 18 is equipped with a gas-liquid mixing mechanism 19, a foam mixing mechanism 20, a foam storage tank 21 and a foam pump 23. The gas-liquid mixing mechanism 19 has an air inlet end, a liquid inlet end and a mixing output end connected to the air inlet end and the liquid inlet end. The mixing output end of the gas-liquid mixing mechanism 19 is connected to the first input end of the foam mixing mechanism 20. The foam storage tank 21 is connected to the second input end of the foam mixing mechanism 20 through the foam pump 23. The foam output end of the foam mixing mechanism 20 is connected to the foam injection pipe 10.

[0049] When the foam generating device 9 is operating, gas and liquid enter the gas-liquid mixing mechanism 19 and mix, and then enter the foam mixing mechanism 20. Simultaneously, the foaming agent pump 23 pumps the foaming agent stored in the foam storage tank 21 into the foam mixing mechanism 20. The foaming agent then mixes with the gas-liquid mixture to generate a large amount of foam. The large amount of foam ultimately enters the foam injection pipe 10 through the foam output end of the foam mixing mechanism 20 and flows along the foam injection pipe 10 into the goaf 2. It should be noted that the foam mixing mechanism 20 can quantitatively calculate the foaming agent extraction rate after calibration based on the wind pressure and water pressure entering the foam generating device 9. The high-pressure water and air flow mix with the foaming agent in the pipeline of the foam mixing mechanism 20.

[0050] Furthermore, a metal mesh 22 is provided at the connection between the foam output end of the foam mixing mechanism 20 and the foam injection pipe 10. The metal mesh 22 is provided for generating stable foam.

[0051] In this embodiment, the advanced support hydraulic support 13 and the support vehicle 18 are articulated via a flexible connection device 16. Preferably, the flexible connection device 16 is a train car connection device, such as a James coupler. This configuration ensures that the support vehicle 18 can turn relative to the advanced support hydraulic support 13 on challenging road sections, thereby adapting to complex underground environments.

[0052] Furthermore, a connecting tunnel 17 is opened on the protective coal pillar 5 for connecting adjacent coal mining working faces, and the foam generating device 9 is arranged in the connecting tunnel 17 .

[0053] In this embodiment, a tunnel compressed air pipeline 14 and a tunnel water supply pipeline 15 are provided on the advance support hydraulic support 13. The tunnel compressed air pipeline 14 is connected to the air inlet end of the gas-liquid mixing mechanism 19, and the tunnel water supply pipeline 15 is connected to the liquid inlet end of the gas-liquid mixing mechanism 19.

[0054] It should be noted that the input ends of the tunnel compressed air pipeline 14 and the tunnel water supply pipeline 15 are laid along the coal mine tunnel to the ground and are connected to the ground air supply equipment and water supply equipment respectively. In addition, the tunnel compressed air pipeline 14 is fed with inert gas. The inert gas not only has pressure to provide power to the foam mixing mechanism 20 and promote the discharge of foam into the goaf 2, but also inertizes the gas in the goaf 2 to prevent the spontaneous combustion of the coal.

[0055] Combine Figure 3 and Figure 5 As shown, each foam release port 12 is provided with an automatic opening assembly, which includes a casing (not shown in the figure), a bevel gear 1 24 , a bevel gear 2 25 , a throttle plate 26 and a pressure plate 27 .

[0056] A casing is provided on the outer wall of the foam injection pipe 10 at the foam release port 12, and the casing is used to position and support bevel gear 1 24 and bevel gear 2 25, and bevel gear 1 24 is meshed with bevel gear 2 25; one end of the pressure plate 27 is fixedly connected to the rotating shaft of bevel gear 1 24, and the other end of the pressure plate 27 extends into the goaf 2, and the throttle plate 26 is located in the foam injection pipe 10 and is fixedly connected to the rotating shaft of bevel gear 2 25. The throttle plate 26 can rotate between a closed position and a throttling position. In the closed position, the throttle plate 26 closes the corresponding foam release port 12; and in the throttling position, the throttle plate 26 opens the corresponding foam release port 12 and prevents the foam from moving backward along the foam injection pipe 10.

[0057] It should be noted that, initially, the throttle plate 26 is in the closed position, at which time the foam can move rearward along the foam injection pipe 10; when the overlying rock stratum 29 above the goaf 2 collapses, the rock presses the pressure plate 27 downward, and the pressure plate 27 drives the bevel gear 1 24 and the bevel gear 2 25 to rotate, and the rotation of the bevel gear 2 25 drives the throttle plate 26 to rotate from the closed position to the throttling position, opening the corresponding foam release port 12 while closing the rear foam injection pipe 10, thereby preventing the foam from moving rearward along the foam injection pipe 10.

[0058] Furthermore, the inner sidewall of the foam injection tube 10 is provided with a limit portion 28 at the throttle position, which is used to limit the rotation angle of the throttle plate 26. It should be noted that when the throttle plate 26 abuts the limit portion 28, the axial direction of the foam injection tube 10 is perpendicular to the plate surface of the throttle plate 26.

[0059] This embodiment also provides a method for plugging air leakage based on the above-mentioned goaf area fixed-point foam injection plugging air leakage device, the method comprising the following steps:

[0060] S1, trenching construction, including: excavating coal wall pipe trenches 11 extending in the front-to-back direction on the protective coal pillars 5 on the left and right sides of the goaf 2; laying foam injection pipes 10 in the coal wall pipe trenches 11;

[0061] S2. Air leakage detection, including: quantitatively releasing SF6 gas 50m from the coal mining face in the air intake tunnel 3 and recording the release time; arranging sampling points at equal distances within the coal mining face and the return air tunnel 4, and monitoring the changes in SF6 gas concentration in real time using an SF6 detector; based on the changes in SF6 gas concentration at each sampling point, by comparing the SF6 gas concentration at different locations, combined with time parameters and position parameters, the location of the air leakage channel and the amount of air leakage are determined;

[0062] The formula for calculating air leakage is:

[0063]

[0064] Where Q is the air leakage, m 3 / s; M is the total amount of SF6 gas injected, g; Δc is the SF6 gas concentration increment measured at the detection point, g / m 3 ; t is the time required for the gas to reach the detection point, s.

[0065] S3. Determine the foam injection position based on the air leakage detection result in step S2: If there is an air leakage channel in the triangular area on one side of the air inlet roadway 3, the foam generating device 9 in the air inlet roadway 3 proceeds to step S4; if there is an air leakage channel in the triangular area on one side of the return air roadway 4, the foam generating device 9 in the return air roadway 4 proceeds to step S4; if there are air leakage channels in the triangular areas on both sides of the goaf 2, the foam generating devices 9 in both the air inlet roadway 3 and the return air roadway 4 proceed to step S4;

[0066] S4, foam preparation, including: connecting the foam generating device 9 to the advance support hydraulic support 13; connecting the output end of the foam generating device 9 to the foam injection pipe 10 in a one-to-one correspondence; the foam generating device 9 prepares and generates foam;

[0067] S5. Foam Injection: The foam generating device 9 delivers the prepared foam to the foam injection pipe 10. The foam moves rearward along the foam injection pipe 10 and is released into the triangular area through the foam release port 12 on the foam injection pipe 10, thereby blocking the air leakage channel within the triangular area. As the overlying rock stratum 29 collapses, the rock presses the pressure plate 27 downward, driving the rotation of bevel gear 1 24 and bevel gear 2 25. The throttle plate 26 rotates from the closed position to the throttle position, opening the foam release port 12 and closing the rear foam injection pipe 10. Foam can be injected into the triangular area of ​​the coal wall near the protective coal pillar 5, blocking the air leakage channel between the goaf 2 and the outside world.

[0068] In this embodiment, the trenching construction position of the coal wall pipe trench 11 is 1-2 meters away from the roadway floor. At this height, construction is easiest and the diffusion range of the foam injection is maximized.

[0069] In this embodiment, the air leakage plugging method further includes:

[0070] S6, synchronous follow-up, including: disconnecting the foam generating device 9 and the foam injection pipe 10, advancing the coal mining working face forward, and the advanced support hydraulic support 13 synchronously drives the foam generating device 9 to move forward to achieve synchronous follow-up, and finally repeating steps S1-S5 until the coal mining operation is stopped.

[0071] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0072] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0073] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0074] In the description of this specification, the terms "one embodiment", "some embodiments", "embodiments", "examples", "specific examples" or "some examples" refer to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example and included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0075] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A device for plugging air leakage by fixed-point foam injection in goaf, characterized by: It includes two foam generating devices (9) and a foam injection pipe (10); The two foam generating devices (9) are respectively arranged in the air inlet tunnel (3) and the return air tunnel (4) of the coal mining working face, and are connected to the advance support hydraulic supports (13) in the air inlet tunnel (3) and the return air tunnel (4). The advance support hydraulic supports (13) can drive the foam generating devices (9) to move forward; Coal wall pipe grooves (11) extending in the front-to-back direction are provided on the protective coal pillars (5) on the left and right sides of the goaf (2). A foam injection pipe (10) is laid in the coal wall pipe groove (11). The output end of the foam generating device (9) is connected to an end of the foam injection pipe (10) away from the goaf (2). The foam injection pipe (10) is provided with a plurality of foam release ports (12) at equal intervals along the length direction. Each foam release port (12) is provided with an automatic opening assembly, which includes a casing, a bevel gear 1 (24), a bevel gear 2 (25), a throttle plate (26) and a pressure plate (27); The outer wall of the foam injection pipe (10) is provided with a casing at the foam release port (12), and the interior of the casing is used for positioning and supporting bevel gear 1 (24) and bevel gear 2 (25), and bevel gear 1 (24) is meshed with bevel gear 2 (25); One end of the pressure plate (27) is fixedly connected to the rotating shaft of the bevel gear 1 (24), and the other end of the pressure plate (27) extends into the goaf (2). The throttle plate (26) is located in the foam injection pipe (10) and is fixedly connected to the rotating shaft of the bevel gear 2 (25), wherein the throttle plate (26) can rotate between a closed position and a throttling position. In the closed position, the throttle plate (26) closes the corresponding foam release port (12); and in the throttling position, the throttle plate (26) opens the corresponding foam release port (12) and prevents the foam from moving to the rear side along the foam injection pipe (10); as the overlying rock layer (29) collapses, the rock presses the pressure plate (27) downward, driving the bevel gear 1 (24) and the bevel gear 2 (25) to rotate, and the throttle plate (26) rotates from the closed position to the throttling position.

2. The goaf area fixed-point foam injection and air leakage blocking device according to claim 1, characterized in that: The foam generating device (9) comprises a carrier vehicle (18), a gas-liquid mixing mechanism (19), a foam mixing mechanism (20), a foam storage tank (21), and a foaming agent pump (23); The front end of the advanced support hydraulic support (13) is hinged to the rear end of the carrier vehicle (18). The carrier vehicle (18) is equipped with a gas-liquid mixing mechanism (19), a foam mixing mechanism (20), a foam storage tank (21), and a foam agent pump (23). The gas-liquid mixing mechanism (19) has an air inlet end, a liquid inlet end, and a mixing output end connected to the air inlet end and the liquid inlet end. The mixing output end of the gas-liquid mixing mechanism (19) is connected to the first input end of the foam mixing mechanism (20). The foam storage tank (21) is connected to the second input end of the foam mixing mechanism (20) through the foam agent pump (23). The foam output end of the foam mixing mechanism (20) is connected to the foam injection pipe (10).

3. The device for plugging air leakage by fixed-point foam injection in goaf according to claim 2, characterized in that: A metal mesh (22) is provided at the connection between the foam output end of the foam mixing mechanism (20) and the foam injection pipe (10).

4. The device for plugging air leakage by fixed-point foam injection in goaf according to claim 2, characterized in that: The advanced support hydraulic support (13) and the carrier vehicle (18) are hinged via a flexible connection device (16).

5. The device for plugging air leakage by fixed-point foam injection in goaf according to claim 2, characterized in that: A tunnel pressure air pipeline (14) and a tunnel water supply pipeline (15) are provided on the advance support hydraulic support (13). The tunnel pressure air pipeline (14) is connected to the air inlet end of the gas-liquid mixing mechanism (19) to supply inert gas to the gas-liquid mixing mechanism (19). The tunnel water supply pipeline (15) is connected to the liquid inlet end of the gas-liquid mixing mechanism (19).

6. The device for plugging air leakage by fixed-point foam injection in goaf according to claim 1, characterized in that: The foam injection pipe (10) has a plurality of sub-pipelines connected in sequence, and adjacent sub-pipelines are detachably connected via quick connectors.

7. A method for plugging air leakage in goafs based on the device for plugging air leakage by fixed-point foam injection according to any one of claims 1 to 6, characterized in that: The air leakage blocking method comprises the following steps: S1. Trenching construction, including: excavating a coal wall pipe groove (11) extending in a front-to-back direction on the protective coal pillars (5) on the left and right sides of the goaf (2); laying a foam injection pipe (10) in the coal wall pipe groove (11); S2. Air leakage detection to determine the location of the air leakage channel and the amount of air leakage; S3. Determine the foam injection position based on the air leakage detection result in step S2: if there is an air leakage channel in the triangular area on one side of the air inlet tunnel (3), the foam generating device (9) in the air inlet tunnel (3) enters step S4; if there is an air leakage channel in the triangular area on one side of the return air tunnel (4), the foam generating device (9) in the return air tunnel (4) enters step S4; if there are air leakage channels in the triangular areas on both sides of the goaf (2), the foam generating devices (9) in both the air inlet tunnel (3) and the return air tunnel (4) enter step S4; S4, foam preparation, including: connecting the foam generating device (9) with the advance support hydraulic support (13); connecting the output end of the foam generating device (9) with the foam injection pipe (10) in a one-to-one correspondence; the foam generating device (9) generates foam; S5. Foam injection: The foam generating device (9) delivers the prepared foam to the foam injection pipe (10). The foam moves toward the rear side along the foam injection pipe (10) and is released into the triangular area through the foam release port (12) to block the air leakage channel in the triangular area.

8. The air leakage plugging method according to claim 7, characterized in that: The air leakage blocking method further comprises: S6, synchronous follow-up, including: disconnecting the foam generating device (9) and the foam injection pipe (10), advancing the coal mining working face forward, and the advanced support hydraulic support (13) synchronously driving the foam generating device (9) to move forward, and repeating steps S1-S5 until the coal mining operation is stopped.

9. The air leakage plugging method according to claim 7, characterized in that: In step S1, the trenching construction position of the coal wall pipe trench (11) is 1-2 meters away from the roadway floor.

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