A method for determining the air leakage coefficient of a coal mine sealing wall

Abstract

This invention relates to a method for determining the air leakage coefficient of a coal mine sealed wall, comprising the following steps: S1, selecting a first detection point A1 and a second detection point A2 in the roadway between the coal mine sealed wall and the goaf; S2, detecting the time Δt it takes for the airflow seeping into the sealed space to travel from the first detection point A1 to the second detection point A2; S3, calculating the air volume Q seeping into the sealed space based on the time Δt it takes for the airflow to travel from the first detection point A1 to the second detection point A2, the distance L between the first detection point A1 and the second detection point A2, and the cross-sectional area S of the roadway; S4, detecting the pressure difference h on both sides of the coal mine sealed wall, and then determining the air leakage coefficient k of the coal mine sealed wall based on the pressure difference h on both sides of the coal mine sealed wall and the air volume Q obtained in step S3. Its beneficial effect is that the method for determining the air leakage coefficient of a coal mine sealed wall of this invention overcomes the problem that existing technologies cannot detect the sealing effect of coal mine sealed walls, and is simple, easy to implement, and easy to operate.

Description

Technical Field

[0001] This invention relates to the field of coal mine sealed walls technology, and in particular to a method for determining the air leakage coefficient of coal mine sealed walls. Background Technology

[0002] Goaf areas formed during coal mining are highly susceptible to fire. When the fire source within the goaf cannot be directly extinguished, to prevent the fire from spreading and to ensure normal mine production, workers typically construct sealed walls in the roadways leading to the goaf, thus sealing it off and preventing fresh air from entering. After the goaf is sealed, the oxygen concentration gradually decreases due to the burning flames, while the concentration of inert gases gradually increases. When the oxygen in the goaf is depleted, the fire source extinguishes due to lack of oxygen.

[0003] Chinese patent document CN217152036U discloses a rapidly constructed coal mine sealing wall to solve the problems of cumbersome construction process and low construction efficiency of coal mine sealing walls. Specifically, flexible mold bags are filled inside the tunnel roof, tunnel floor and tunnel sides. Shaped metal mesh is evenly distributed on the inner and outer sides of the flexible mold bags to help shape the flexible mold bags. Shaped steel pipes are distributed on the outer side of the shaped metal mesh. The coal mine sealing wall is formed by splicing and installing the flexible mold bags, shaped steel pipes and shaped metal mesh. The above-mentioned coal mine sealing wall has the following defects: (1) After the coal mine sealing wall is constructed, the sealing effect of the coal mine sealing wall cannot be tested, so it is impossible to evaluate whether the constructed coal mine sealing wall meets the requirements; (2) When the coal mine sealing wall is damaged by external force, the operators cannot find it in time and repair it.

[0004] Therefore, there is an urgent need to provide a method for determining the air leakage coefficient of a coal mine sealed wall that can detect the sealing effect of the sealed wall. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for determining the air leakage coefficient of a coal mine sealed wall, which solves the technical problem that the prior art cannot detect the sealing effect of a coal mine sealed wall.

[0007] (II) Technical Solution

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

[0009] This invention provides a method for determining the air leakage coefficient of a coal mine sealed wall, comprising the following steps:

[0010] S1. Select two points in the roadway between the coal mine sealed wall and the goaf area. The point closer to the coal mine sealed wall is designated as the first detection point A1, and the other point farther away from the coal mine sealed wall is designated as the second detection point A2.

[0011] S2, the time Δt it takes for the airflow that has seeped into the sealed space to move from the first detection point A1 to the second detection point A2;

[0012] S3. Calculate the airflow Q that infiltrates into the sealed space based on the time Δt it takes for the airflow to move from the first detection point A1 to the second detection point A2, obtained in step S2. The airflow Q is obtained from formula (1):

[0013]

[0014] In the formula, L is the distance between the first detection point A1 and the second detection point A2, Δt is the time it takes for the airflow to move from the first detection point A1 to the second detection point A2, and S is the cross-sectional area of ​​the roadway.

[0015] S4. Detect the pressure difference h on both sides of the coal mine sealed wall, and then determine the air leakage coefficient k of the coal mine sealed wall based on the pressure difference h on both sides of the coal mine sealed wall and the air volume Q obtained in step S3.

[0016] Optionally, the air leakage coefficient k of the coal mine sealed wall is obtained from formula (2):

[0017]

[0018] In the formula, Q is the air volume that permeates into the sealed space, C is the perimeter of the sealed wall of the coal mine, h is the pressure difference on both sides of the sealed wall of the coal mine, and d is the thickness of the sealed wall of the coal mine.

[0019] Optionally, in step S2, the oxygen concentration at the first detection point A1 and the second detection point A2 are monitored in real time by the first oxygen concentration real-time monitoring device and the second oxygen concentration real-time monitoring device, respectively, to obtain the time-oxygen concentration curves at the first detection point A1 and the second detection point A2. The time Δt for the airflow to move from the first detection point A1 to the second detection point A2 is determined by the curve.

[0020] Optionally, the distance between the first detection point A1 and the coal mine sealed wall is 10-20m, the distance between the second detection point A2 and the coal mine sealed wall is 30-40m, and the distance L between the first detection point A1 and the second detection point A2 is 20-30m.

[0021] Optionally, the first real-time oxygen concentration monitoring device includes: a dust filter, a first bundle of tubes, and a gas sampling and analysis assembly located outside the sealed wall of the coal mine;

[0022] The gas sampling and analysis component is connected to one end of the first bundle tube, and the other end of the first bundle tube extends through the sealed wall of the coal mine to the first detection point A1. A dust filter is installed at the end of the first bundle tube away from the gas sampling and analysis component to prevent dust from entering the first bundle tube.

[0023] Optionally, the second real-time oxygen concentration monitoring device includes: a dust filter, a second bundle of tubes, and a gas sampling and analysis assembly located outside the sealed wall of the coal mine;

[0024] The gas sampling and analysis component is connected to one end of the second bundle tube, and the other end of the second bundle tube extends through the sealed wall of the coal mine to the second detection point A2. A dust filter is installed at the end of the second bundle tube away from the gas sampling and analysis component to prevent dust from entering the second bundle tube.

[0025] Optionally, the gas sampling and analysis component includes:

[0026] A bundled tube multi-channel gas sampling pump, whose inlet is connected to the first or second bundled tube, is used to extract gas from a confined space.

[0027] The bundled tube distribution box has its air inlet connected to the air outlet of the bundled tube multi-channel gas sampling pump, and is used to filter moisture in the sampled gas.

[0028] The bundled tube monitoring substation has its air inlet connected to the air outlet of the bundled tube distribution box, and is used to analyze the oxygen concentration in the sampled gas in real time.

[0029] Optionally, in step S4, the pressure difference h on both sides of the coal mine sealed wall is detected by a differential pressure testing device;

[0030] The differential pressure testing device includes a differential pressure testing tube and a differential pressure measuring device. The differential pressure measuring device is connected to one end of the differential pressure testing tube, and the other end of the differential pressure testing tube passes through the sealed wall of the coal mine and enters the sealed space.

[0031] (III) Beneficial Effects

[0032] The beneficial effects of this invention are as follows: The method for determining the air leakage coefficient of a coal mine sealed wall includes the following steps: S1, selecting a first detection point A1 and a second detection point A2 in the roadway between the coal mine sealed wall and the goaf; S2, detecting the time Δt it takes for the airflow that seeps into the sealed space to move from the first detection point A1 to the second detection point A2; S3, determining the air leakage coefficient based on the time Δt it takes for the airflow that seeps into the sealed space to move from the first detection point A1 to the second detection point A2, and the distance between the first detection point A1 and the second detection point A2. S3 calculates the air volume Q that infiltrates into the sealed space based on the distance L and the cross-sectional area S of the roadway; S4 detects the pressure difference h on both sides of the coal mine sealed wall, and then determines the air leakage coefficient k of the coal mine sealed wall based on the pressure difference h on both sides of the coal mine sealed wall and the air volume Q obtained in step S3. Compared with the existing technology, it determines the air leakage coefficient k of the coal mine sealed wall by detecting the air leakage of the coal mine sealed wall and the pressure difference between the inside and outside of the coal mine sealed wall, thus providing an important reference for evaluating the sealing effect of the coal mine sealed wall, and has a very broad prospect for engineering application. Attached Figure Description

[0033] Figure 1 This is a top view schematic diagram of the coal mine working face and goaf in Embodiment 1 of the present invention;

[0034] Figure 2 for Figure 1 The schematic diagram of the first real-time oxygen concentration monitoring device is shown in the figure. The first real-time oxygen concentration monitoring device includes: a bundle tube monitoring substation, a bundle tube distribution box, a bundle tube multi-channel gas sampling pump, a first bundle tube, and a dust filter.

[0035] Figure 3 for Figure 1 The curves showing the relationship between measured oxygen concentration and time at the first and second detection points A1 and A2 in the data;

[0036] Figure 4 This is a top view schematic diagram of the coal mine working face and goaf in Embodiment 2 of the present invention.

[0037] [Explanation of Labels in the Attached Image]

[0038] 1: First real-time oxygen concentration monitoring device; 2: Second real-time oxygen concentration monitoring device; 3: Bundle tube monitoring substation; 4: Bundle tube distribution box; 5: Bundle tube multi-channel gas sampling pump; 6: Dust filter; 7: First bundle tube; 8: Second bundle tube; 9: Differential pressure testing device; 10: Differential pressure testing tube; 11: Differential pressure measuring device; 12: Tracer gas release device; 13: First real-time tracer gas monitoring device; 14: Second real-time tracer gas monitoring device. Detailed Implementation

[0039] To better explain and facilitate understanding of the present invention, a detailed description of the invention is provided below with reference to the accompanying drawings and specific embodiments. In this document, the outer side of the coal mine sealing wall refers to the side facing away from the goaf, and the inner side of the coal mine sealing wall refers to the side facing the goaf.

[0040] Example 1:

[0041] Reference Figure 1 , Figure 2 and Figure 3 This embodiment provides a method for determining the air leakage coefficient of a coal mine sealed wall, including the following steps:

[0042] S1. Select two points in the roadway between the coal mine sealed wall and the goaf area. The point closer to the coal mine sealed wall is designated as the first detection point A1, and the other point farther away from the coal mine sealed wall is designated as the second detection point A2.

[0043] S2. The oxygen concentration at the first detection point A1 and the second detection point A2 are monitored in real time by the first oxygen concentration real-time monitoring device 1 and the second oxygen concentration real-time monitoring device 2, respectively, and the time-oxygen concentration curves at the first detection point A1 and the second detection point A2 are obtained. The time Δt for the airflow that permeates into the closed space to move from the first detection point A1 to the second detection point A2 is determined by the curve.

[0044] S3. Calculate the airflow Q that infiltrates into the sealed space based on the time Δt it takes for the airflow to move from the first detection point A1 to the second detection point A2, obtained in step S2. The airflow Q is obtained from formula (1):

[0045]

[0046] In the formula, L is the distance between the first detection point A1 and the second detection point A2, in meters (m); Δt is the time it takes for the airflow to travel from the first detection point A1 to the second detection point A2, in seconds (s); and S is the cross-sectional area of ​​the roadway, in square meters (m²). 2 ;

[0047] S4. Test the pressure difference h on both sides of the coal mine sealed wall using the pressure difference testing device 9, and then determine the air leakage coefficient k of the coal mine sealed wall based on the pressure difference h on both sides of the coal mine sealed wall and the air volume Q obtained in step S3.

[0048] Combination Figure 3 As shown, the time Δt for the airflow infiltrating into the sealed space to move from the first detection point A1 to the second detection point A2 is the time difference between the peak oxygen concentrations at the first detection point A1 and the second detection point A2. The specific principle is as follows: According to the ideal gas law, changes in the pressure difference between the inside and outside of the coal mine's sealed wall will cause air leakage through the sealed wall. That is, when the pressure outside the sealed wall (atmospheric pressure) is greater than the pressure inside the sealed wall, air leaks from the outside into the sealed space through the sealed wall, causing an increase in the pressure inside the sealed space. Therefore, as the pressure difference between the inside and outside of the sealed wall gradually increases, the air leakage also gradually increases, and simultaneously, the oxygen concentrations at the first detection point A1 and the second detection point A2 also gradually increase. For a goaf that has been sealed for a period of time, it can be assumed that the amount of gas escaping from the sealed space is relatively small. Furthermore, since the sealed space in a mine is generally large, it can be assumed that the absolute pressure inside the sealed space is relatively constant. Therefore, the change in the pressure difference between the inside and outside of the coal mine's sealed wall is mainly caused by fluctuations in the atmospheric pressure outside the sealed wall. Due to the cyclical change in outside temperature—higher during the day and lower at night—atmospheric pressure also fluctuates cyclically. (See also...) Figure 3Due to the periodic fluctuations in atmospheric pressure, the oxygen concentrations at the first detection point A1 and the second detection point A2 also fluctuate periodically. Furthermore, because the distances between the first and second detection points A1 and the coal mine's sealed wall are different, the changes in oxygen concentration at these points are not synchronized. When the pressure difference between the inside and outside of the sealed wall is at its maximum, the air leakage of the sealed wall is also at its maximum. At this time, the oxygen concentration in the airflow entering the sealed space is also at its maximum. This airflow passes through the first and second detection points A1 and A2 sequentially, causing the oxygen concentrations at A1 and A2 to reach their peak values ​​successively. By comparing the time it takes for the airflow to reach its peak value at A1 and A2, the time Δt for the airflow to travel from A1 to A2 can be obtained. Dividing the distance L between A1 and A2 by Δt yields the airflow velocity. Multiplying the airflow velocity by the cross-sectional area S of the tunnel yields the airflow volume.

[0049] Furthermore, the air leakage coefficient k of the coal mine sealed wall is obtained from formula (2):

[0050]

[0051] In the formula, Q is the air volume that permeates into the sealed space, in m3 / s; C is the perimeter of the sealed wall in the coal mine, in m; h is the pressure difference between the two sides of the sealed wall in the coal mine, in Pa; and d is the thickness of the sealed wall in the coal mine, in m.

[0052] Furthermore, the distance between the first detection point A1 and the coal mine sealed wall is 10-20m, the distance between the second detection point A2 and the coal mine sealed wall is 30-40m, and the distance L between the first detection point A1 and the second detection point A2 is 20-30m.

[0053] Specifically, the first real-time oxygen concentration monitoring device 1 includes: a dust filter 6, a first bundle tube 7, and a gas sampling and analysis component located outside the sealed wall of the coal mine. The gas sampling and analysis component is connected to one end of the first bundle tube 7, and the other end of the first bundle tube 7 extends through the sealed wall of the coal mine to the first detection point A1. Furthermore, a dust filter 6 is installed at the end of the first bundle tube 7 away from the gas sampling and analysis component to prevent dust from entering the first bundle tube 7. During use, the gas sampling and analysis component connects to the sealed space through the first bundle tube 7 and samples the gas at the first detection point A1, thereby detecting the oxygen concentration at the first detection point A1 in real time.

[0054] The second real-time oxygen concentration monitoring device 2 includes a dust filter 6, a second bundle tube 8, and a gas sampling and analysis component located outside the sealed wall of the coal mine. The gas sampling and analysis component is connected to one end of the second bundle tube 8, and the other end of the second bundle tube 8 extends through the sealed wall of the coal mine to the second detection point A2. Furthermore, a dust filter 6 is installed at the end of the second bundle tube 8 away from the gas sampling and analysis component to prevent dust from entering the second bundle tube 8. During use, the gas sampling and analysis component connects to the sealed space through the second bundle tube 8 and samples the gas at the second detection point A2, thereby detecting the oxygen concentration at the second detection point A2 in real time.

[0055] Furthermore, the gas sampling and analysis component includes:

[0056] The bundled tube multi-channel gas sampling pump 5 has its inlet connected to the first bundled tube 7 or the second bundled tube 8, and is used to extract gas in a closed space.

[0057] The bundle tube branch box 4 has its air inlet connected to the air outlet of the bundle tube multi-channel gas sampling pump 5, and is used to filter moisture in the sampled gas.

[0058] The bundle tube monitoring substation 3 has its air inlet connected to the air outlet of the bundle tube distribution box 4, and is used to analyze the oxygen concentration in the sampled gas in real time.

[0059] Furthermore, the differential pressure testing device 9 includes a differential pressure testing tube 10 and a differential pressure measuring device 11. The differential pressure measuring device 11 is connected to one end of the differential pressure testing tube 10, and the other end of the differential pressure testing tube 10 passes through the coal mine sealed wall and enters the sealed space. During use, the differential pressure testing tube 10 can pass through the observation hole on the coal mine sealed wall to enter the sealed space, while the differential pressure measuring device 11 is connected to the sealed space through the differential pressure testing tube 10, thereby achieving the purpose of detecting the pressure difference between the inside and outside of the coal mine sealed wall.

[0060] Example 2:

[0061] See Figure 4 This embodiment provides another method for determining the air leakage coefficient of a coal mine sealed wall, including the following steps:

[0062] S1. Select two points in the roadway between the coal mine sealed wall and the goaf area. The point closer to the coal mine sealed wall is designated as the first detection point A1, and the other point farther away from the coal mine sealed wall is designated as the second detection point A2.

[0063] S2. Place a tracer gas release device 12, a first tracer gas real-time monitoring device 13 and a second tracer gas real-time monitoring device 14 on the outside of the coal mine sealed wall. The first tracer gas real-time monitoring device 13 is connected to a third bundle tube, which passes through the coal mine sealed wall and extends to the first detection point A1. The second tracer gas real-time monitoring device 14 is connected to a fourth bundle tube, which passes through the coal mine sealed wall and extends to the second detection point A2.

[0064] S3. Open the tracer gas release device 12, the first tracer gas real-time monitoring device 13 and the second tracer gas real-time monitoring device 14. By comparing the time when the first tracer gas real-time monitoring device 13 and the second tracer gas real-time monitoring device 14 detect the tracer gas, determine the time Δt when the airflow that has penetrated into the sealed space moves from the first detection point A1 to the second detection point A2.

[0065] S4. Calculate the airflow Q that infiltrates into the sealed space based on the time Δt it takes for the airflow to move from the first detection point A1 to the second detection point A2, obtained in step S3. The airflow Q is obtained from formula (1):

[0066]

[0067] In the formula, L is the distance between the first detection point A1 and the second detection point A2, in meters (m); Δt is the time it takes for the airflow to travel from the first detection point A1 to the second detection point A2, in seconds (s); and S is the cross-sectional area of ​​the roadway, in square meters (m²). 2 ;

[0068] S5. Test the pressure difference h on both sides of the coal mine sealed wall using the pressure difference testing device 9, and then determine the air leakage coefficient k of the coal mine sealed wall based on the pressure difference h on both sides of the coal mine sealed wall and the air volume Q obtained in step S4.

[0069] The principle of this embodiment for detecting the time required for the airflow to move from the first detection point A1 to the second detection point A2 is as follows: the tracer gas release device 12 releases tracer gas, which, along with the airflow, passes through the coal mine's sealed wall and enters the sealed space, moving towards the goaf area, and sequentially passes through the first detection point A1 and the second detection point A2, thereby being detected by the first tracer gas real-time monitoring device 13 and the second tracer gas real-time monitoring device 14. Therefore, by comparing the time it takes for the first tracer gas real-time monitoring device 13 and the second tracer gas real-time monitoring device 14 to detect the tracer gas, the time Δt for the airflow that has penetrated into the sealed space to move from the first detection point A1 to the second detection point A2 can be obtained.

[0070] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0071] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0072] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," or "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0073] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for determining the air leakage coefficient of a sealed wall in a coal mine, characterized in that: Includes the following steps: S1. Select two points in the roadway between the coal mine sealed wall and the goaf area. The point closer to the coal mine sealed wall is designated as the first detection point A1, and the other point farther away from the coal mine sealed wall is designated as the second detection point A2. S2, the time Δt it takes for the airflow that has seeped into the sealed space to move from the first detection point A1 to the second detection point A2; S3. Calculate the airflow Q that infiltrates into the sealed space based on the time Δt it takes for the airflow to move from the first detection point A1 to the second detection point A2, obtained in step S2. The airflow Q is obtained from formula (1): （1）； In the formula, L is the distance between the first detection point A1 and the second detection point A2, Δt is the time it takes for the airflow to move from the first detection point A1 to the second detection point A2, and S is the cross-sectional area of ​​the roadway. S4. Detect the pressure difference h on both sides of the coal mine sealed wall, and then determine the air leakage coefficient k of the coal mine sealed wall based on the pressure difference h on both sides of the coal mine sealed wall and the air volume Q obtained in step S3. The air leakage coefficient k of the sealed wall in the coal mine is obtained from formula (2): （2）； In the formula, Q is the air volume that permeates into the sealed space, C is the perimeter of the sealed wall of the coal mine, h is the pressure difference on both sides of the sealed wall of the coal mine, and d is the thickness of the sealed wall of the coal mine.

2. The method for determining the air leakage coefficient of a coal mine sealed wall as described in claim 1, characterized in that: In step S2, the oxygen concentration at the first detection point A1 and the second detection point A2 are monitored in real time by the first oxygen concentration real-time monitoring device and the second oxygen concentration real-time monitoring device, respectively, to obtain the time-oxygen concentration curves at the first detection point A1 and the second detection point A2. The time Δt for the airflow to move from the first detection point A1 to the second detection point A2 is determined by the curve.

3. The method for determining the air leakage coefficient of a coal mine sealed wall as described in claim 2, characterized in that: The distance between the first detection point A1 and the coal mine sealed wall is 10-20m, the distance between the second detection point A2 and the coal mine sealed wall is 30-40m, and the distance L between the first detection point A1 and the second detection point A2 is 20-30m.

4. The method for determining the air leakage coefficient of a coal mine sealed wall as described in claim 2, characterized in that: The first real-time oxygen concentration monitoring device includes: a dust filter, a first bundle of tubes, and a gas sampling and analysis component located outside the sealed wall of the coal mine. The gas sampling and analysis component is connected to one end of the first bundle tube, and the other end of the first bundle tube extends through the sealed wall of the coal mine to the first detection point A1. A dust filter is installed at the end of the first bundle tube away from the gas sampling and analysis component to prevent dust from entering the first bundle tube.

5. The method for determining the air leakage coefficient of a coal mine sealed wall as described in claim 2, characterized in that: The second real-time oxygen concentration monitoring device includes: a dust filter, a second bundle of tubes, and a gas sampling and analysis component located outside the sealed wall of the coal mine. The gas sampling and analysis component is connected to one end of the second bundle tube, and the other end of the second bundle tube extends through the sealed wall of the coal mine to the second detection point A2. A dust filter is installed at the end of the second bundle tube away from the gas sampling and analysis component to prevent dust from entering the second bundle tube.

6. The method for determining the air leakage coefficient of a coal mine sealed wall as described in claim 4 or 5, characterized in that: The gas sampling and analysis components include: A bundled tube multi-channel gas sampling pump, whose inlet is connected to the first or second bundled tube, is used to extract gas from a confined space. The bundled tube distribution box has its air inlet connected to the air outlet of the bundled tube multi-channel gas sampling pump, and is used to filter moisture in the sampled gas. The bundled tube monitoring substation has its air inlet connected to the air outlet of the bundled tube distribution box, and is used to analyze the oxygen concentration in the sampled gas in real time.

7. The method for determining the air leakage coefficient of a coal mine sealed wall as described in claim 1, characterized in that: In step S4, the pressure difference h on both sides of the coal mine sealed wall is detected by a differential pressure testing device; The differential pressure testing device includes a differential pressure testing tube and a differential pressure measuring device. The differential pressure measuring device is connected to one end of the differential pressure testing tube, and the other end of the differential pressure testing tube passes through the sealed wall of the coal mine and enters the sealed space.

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