Equipment for detecting methane concentration of coal mine

Abstract

The invention discloses a coal mine methane concentration detection device, which relates to the field of concentration detection, and comprises: a housing having a rectangular box structure; the gas concentration detector is installed above the shell, the detection end of the gas concentration detector extends into the shell, a plurality of probes are installed on the top wall in the shell, and the plurality of probes are connected with the detection end through an RS485 bus; the multiple air inlet pipes are fixed to the bottom of the shell, and the multiple air inlet pipes are arranged below the probes in a one-to-one correspondence mode; six detection elements including a catalytic combustion probe, an electrochemical probe, a paramagnetic / galvanic probe, a carbon dioxide detection probe and a temperature sensor are integrated in a single shell, so that synchronous detection of concentrations of methane, carbon monoxide, hydrogen sulfide, oxygen and carbon dioxide and ambient temperature is realized; and the equipment cost, the installation space and the management complexity are greatly reduced, and the cost performance is high.

Description

Technical Field

[0001] This invention relates to the field of concentration detection technology, and more specifically to a device for detecting methane concentration in coal mines. Background Technology

[0002] The underground environment of coal mines is complex, containing various hazardous gases such as methane, carbon monoxide, and hydrogen sulfide, along with high concentrations of dust and abnormal temperature fluctuations, posing a serious threat to safe production. Current technologies for detecting gas concentrations in coal mines mainly suffer from the following problems:

[0003] 1. Limited functionality and low integration: Traditional detection devices can usually only detect a single gas parameter. To achieve comprehensive monitoring of methane, carbon monoxide, hydrogen sulfide, oxygen, carbon dioxide, and temperature, multiple independent devices need to be deployed, resulting in a complex system, high cost, large space occupation, and difficulty in centralized management.

[0004] 2. Difficult to maintain and prone to clogging and failure: The dust concentration in coal mines is extremely high. The air intake system of existing detection equipment lacks an effective self-cleaning mechanism. The sensor probe and filter device are easily clogged by coal dust, requiring frequent manual disassembly, cleaning or replacement. This not only results in a large workload and high cost, but also causes the equipment to malfunction during maintenance, posing a safety hazard.

[0005] To address this problem, we provide a device for detecting methane concentration in coal mines. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a device for detecting methane concentration in coal mines, which enables simultaneous detection of methane, carbon monoxide, hydrogen sulfide, oxygen, carbon dioxide concentrations, and ambient temperature, significantly reducing equipment cost, installation space, and management complexity, and offering high cost-effectiveness.

[0007] To achieve the above objectives, the present invention provides a device for detecting methane concentration in coal mines, comprising: The housing is a rectangular box structure; A gas concentration detector is installed on top of a housing with its detection end extending into the housing. Multiple probes are installed on the top wall inside the housing, and the multiple probes are connected to the detection end via an RS485 bus. The air intake pipe is provided in multiple ways. The air intake pipe is fixed to the bottom of the housing and is respectively provided below each probe. The housing contains a small pump mechanism to draw gas in through the inlet pipe and apply it to the area around the corresponding probe. Inside the housing, between the probe and the inlet pipe, there is a filter assembly for filtering dust from the gas. At the bottom of the housing, there is a gas trough that connects the inlet pipe to the inside of the housing, and a gas reversing mechanism is provided in the gas trough.

[0008] As a further optimization of the above solution, the small pump mechanism includes a pump body, an air inlet main pipe and an air outlet pipe. The air inlet main pipe is provided with multiple air inlet auxiliary pipes, each of which corresponds to one of the multiple probes. Each air inlet auxiliary pipe is provided with a solenoid valve.

[0009] As a further optimization of the above scheme, multiple probes are included, including a catalytic combustion probe, a first electrochemical probe, a second electrochemical probe, a paramagnetic / galvanic probe, a carbon dioxide detection probe, and a temperature detection probe, which are used to detect the concentrations of methane, carbon monoxide, hydrogen sulfide, oxygen, carbon dioxide, and ambient temperature, respectively.

[0010] As a further optimization of the above solution, the filter assembly includes a horizontal partition and filter cotton. The horizontal partition is horizontally fixedly installed inside the housing and isolates the inside of the housing into upper and lower chambers. The horizontal partition is provided with multiple rectangular grooves. The filter cotton is installed in the rectangular grooves. The number of rectangular grooves corresponds to the number of probes and is located between the probes and the corresponding air inlet pipes. The small pump mechanism is located in the upper chamber.

[0011] As a further optimization of the above solution, the gas reversing mechanism includes a movable sealing plate, a chute, a rotating shaft, an electromagnet, a magnetic block, a first baffle, and a second baffle. The chute is arranged along the height direction of the gas trough at its edge. The movable sealing plate is arranged horizontally and movably placed in the gas trough. One side of the movable sealing plate is rotatably set by the rotating shaft, and the end of the rotating shaft is slidably set inside the chute. The magnetic block is fixedly installed on the lower surface of the movable sealing plate and close to the rotating shaft. A base plate is fixed on the inner wall of the air inlet pipe. The electromagnet is fixedly installed on the upper surface of the base plate and correspondingly set directly below the magnetic block. The first baffle and the second baffle are respectively fixed on the inner wall of the gas trough on the side away from the chute, with the first baffle located at the upper end of the gas trough and the second baffle located at the lower end of the gas trough.

[0012] As a further optimization of the above solution, the air outlet pipe is positioned at the top center of the housing, and the air inlet auxiliary pipe faces the bottom of the corresponding probe.

[0013] As a further optimization of the above solution, a bent metal sheet is fixedly installed at the upper opening of the gas tank to generate vibration when the gas flows through, thereby helping to remove dust adhering to the filter cotton.

[0014] As a further optimization of the above scheme, the lower chamber is provided with multiple vertical baffles, which are located between adjacent air intake pipes.

[0015] As a further optimization of the above solution, the housing is assembled from upper and lower box bodies, and at least one probe is left inactive to allow for at least one air intake pipe for exhaust.

[0016] As a further optimization of the above scheme, multiple probes are used to detect various content data in the gas. The detection results are transmitted to the gas concentration detector via RS485 bus. The gas concentration detector is equipped with an audible and visual alarm to warn coal mine workers.

[0017] The device for detecting methane concentration in coal mines according to the present invention has the following beneficial effects: The present invention provides a highly integrated and multifunctional device for detecting methane concentration in coal mines: integrating six detection elements—catalytic combustion probe, electrochemical probe, paramagnetic / galvanic probe, carbon dioxide detection probe, and temperature sensor—into a single housing, enabling simultaneous detection of methane, carbon monoxide, hydrogen sulfide, oxygen, carbon dioxide concentrations, and ambient temperature. This significantly reduces equipment costs, installation space requirements, and management complexity, resulting in a high cost-performance ratio. Through the synergistic action of a small pump mechanism, filter components and gas reversing mechanism, the filter cotton is flushed with exhaust airflow after the test is completed, automatically removing the adhering coal dust. The vibration of the bent metal sheet assists in dust removal, which significantly extends the service life of the filter components and probes, eliminates the need for manual maintenance for a long period of time, and reduces the cost of use and safety risks. The gas reversing mechanism, through the ingenious cooperation of the movable sealing plate, electromagnet and baffle, forms a reliable one-way flow mechanism, which effectively avoids the backflow and mixing of the detection gas and the external environment gas, eliminates cross-contamination, ensures that each probe independently and accurately detects the corresponding gas parameters, and improves measurement accuracy and response reliability. Through a distributed structure with multiple air inlets corresponding to one probe, and independent control of solenoid valves in the auxiliary air inlet pipes, selective sampling and detection of gases in different roadway areas can be achieved. All data is aggregated to the main controller via RS485 bus to form a zoned monitoring network, which can accurately locate the location of hazardous sources and provide precise guidance for emergency response. The housing adopts a rectangular box splicing structure, and the internal space is optimized through horizontal and vertical partitions. The integrated small pump mechanism has a volume of only 32×22×37mm, and the size of all probes is controlled within Φ20mm×16mm. The overall equipment is small in size and light in weight, which makes it easy to deploy flexibly in the narrow space of underground coal mines. Moreover, the layout of each component is reasonable, the gas flow path is clear, and they do not interfere with each other.

[0018] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope as a result, and that the embodiments of the present invention include many changes, modifications and equivalents within the spirit and scope of the appended claims. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the device structure for detecting methane concentration in coal mines according to the present invention; Figure 2 This is a three-dimensional structural cross-sectional view of the device for detecting methane concentration in coal mines according to the present invention; Figure 3 For the present invention Figure 2 Enlarged schematic diagram of the structure at point A in the middle; Figure 4 For the present invention Figure 2 Enlarged schematic diagram of the structure at point B; Figure 5 This is a cross-sectional view of the plan structure of the device for detecting methane concentration in coal mines according to the present invention; Figure 6 For the present invention Figure 5 Enlarged schematic diagram of the structure at point C; Figure 7 This is a schematic diagram of the airflow trajectory in the equipment for detecting methane concentration in coal mines according to the present invention; Figure 8 This is a schematic diagram of the structure of the device for detecting methane concentration in coal mines according to the present invention during air discharge; Figure 9 This is a schematic diagram of the structure of the device for detecting methane concentration in coal mines according to the present invention when air enters; Figure 10 This is a schematic diagram of the structure of the device for detecting methane concentration in coal mines according to the present invention, in which the movable sealing plate is in an upward-opening state when air enters. Figure 11 This is a schematic diagram of the initial state structure of the movable sealing plate in the equipment for detecting methane concentration in coal mines according to the present invention when air is discharged; Figure 12 This is a schematic diagram of the structure of the device for detecting methane concentration in coal mines according to the present invention, showing the movable sealing plate opening downwards when air is discharged.

[0020] In the diagram: 1. Housing; 2. Gas concentration detector; 3. Inlet pipe; 4. Detection end; 5. Probe; 6. RS485 bus; 7. Horizontal partition; 8. Filter cotton; 9. Pump body; 10. Outlet pipe; 11. Main inlet pipe; 12. Auxiliary inlet pipe; 13. Vertical partition; 14. Gas tank; 15. Bending metal sheet; 16. Movable sealing plate; 17. Slide groove; 18. Rotating shaft; 19. First baffle; 20. Second baffle; 21. Base plate; 22. Electromagnet; 23. Magnetic block; 24. Solenoid valve. Detailed Implementation

[0021] Please refer to the instruction manual appendix. Figure 1-12 The present invention provides a technical solution: a device for detecting methane concentration in coal mines, comprising: a housing 1, a gas concentration detector 2 (with a display screen) and an air inlet pipe 3.

[0022] refer to Figure 1 and Figure 2 As shown, housing 1 is a rectangular box structure, assembled from upper and lower box sections. Gas concentration detector 2 is installed on top of housing 1, displaying corresponding prompts. It also features an audible and visual alarm to alert workers in the coal mine. A detection end 4 is located at the bottom of gas concentration detector 2, extending into the interior of housing 1. Several probes 5 are installed on the inner top wall of housing 1. In this design, six probes 5 are used, and all six probes 5 are connected to the detection end 4 via an RS485 bus 6. Specifically: The six probes are: catalytic combustion probe, first electrochemical probe, second electrochemical probe, paramagnetic / galvanic probe, carbon dioxide detection probe, and temperature detection probe. Among them, the catalytic combustion probe is used to detect methane (CH4), model: MJZC-4CH4, size: Φ20mm×16mm (diameter×height), range: 0-5%, and is used to prevent gas explosions in coal mines; The first electrochemical probe is used to detect carbon monoxide (CO). The model is Alpha Sensor CO-BF, and the size is Φ20mm×16mm (diameter×height). The measurement range is 0-999ppm. It is used to provide early warning of spontaneous combustion of coal in coal mines. The second electrochemical probe is used to detect hydrogen sulfide (H2S). The model is Alpha Sensor H2S-BF, and the dimensions are Φ20mm×16mm (diameter×height). The measurement range is 0-500ppm. It is used to prevent hydrogen sulfide poisoning in coal mines. The paramagnetic / galvanic probe is used to detect oxygen (O2). The model is Alpha Sensor O2-A2, and the dimensions are Φ20mm×16mm (diameter×height). The measurement range is 0-30%, and it is used to prevent workers from suffocating in coal mines. The carbon dioxide detection probe is used to detect carbon dioxide (CO2). The model is Sifang Optoelectronics MH-490B, and the dimensions are 20mm×20mm×11mm (length×width×height). It mainly relies on an infrared absorption sensor to detect carbon dioxide concentration (volume percentage). The measurement range is 0-5.00%, and it is used to prevent asphyxiation of workers in coal mines. The temperature detection probe uses a temperature sensor to detect ambient temperature. The model is PT100-A grade armored platinum resistance thermometer, and the dimensions are Φ3mm×15mm (diameter×height). The measurement range is 0-100℃. It is used to detect whether the temperature in the coal mine is abnormal, so as to ventilate in time or prevent spontaneous combustion of coal.

[0023] In this invention, the air inlet pipe 3 is integrally set at the bottom of the housing 1. A gas groove 14 is provided at the bottom of the housing 1. The air inlet pipe 3 and the housing 1 are connected through the gas groove 14. Several air inlet pipes 3 are provided, and each air inlet pipe 3 is respectively set below the probe 5. When detecting gas, a small pump mechanism set inside the housing 1 draws the gas in the coal mine from the air inlet pipe 3 into the housing 1 and acts on the area around the corresponding probe 5, thereby detecting methane, carbon monoxide, hydrogen sulfide, oxygen and carbon dioxide in the gas, as well as ambient temperature data. A single device integrates multiple sensor probes. Multiple housings 1 are set at different locations along the coal mine roadway (working face and return airway). All sensor probe data are collected by the main controller to realize zoned monitoring and accurately locate the location of hazardous sources. This replaces the traditional method of using a single sensor device to detect a single type of data, and has a better cost performance.

[0024] refer to Figures 2 to 4 As shown, for high dust environments in coal mines, the present invention provides a filter assembly inside the housing 1. The filter assembly includes a transverse partition 7 and filter cotton 8. The transverse partition 7 is horizontally fixed inside the housing 1 and separates the interior of the housing 1 into upper and lower chambers. The transverse partition 7 is provided with multiple rectangular grooves for connecting the upper and lower chambers. The filter cotton 8 is installed in the rectangular grooves. The number of rectangular grooves corresponds to the number of probes 5, and the rectangular grooves are located between the probes 5 and the corresponding air inlet pipes 3. A small pump mechanism is located in the upper chamber. When the small pump mechanism is started, external gas enters through the inlet pipe 3 and passes through the gas tank 14 into the lower chamber. Then, the gas is filtered by the filter cotton 8 and enters the upper chamber and blown onto the surface of the corresponding probe 5. The probe 5 is used to detect the methane, carbon monoxide, hydrogen sulfide, oxygen or carbon dioxide in the gas, as well as the ambient temperature data.

[0025] As the core of this invention, a gas reversing mechanism was added to the gas tank 14, and improvements were made to the small pump mechanism, specifically: The gas reversing mechanism includes a movable sealing plate 16, a slide 17, a rotating shaft 18, an electromagnet 22, a magnetic block 23, a first baffle 19, and a second baffle 20. The slide 17 is arranged along the height of the gas tank 14 and is located at the edge of the gas tank 14. The movable sealing plate 16 is horizontally arranged and movably placed in the gas tank 14. One side of the movable sealing plate 16 is rotatably set by the rotating shaft 18, and the end of the rotating shaft 18 is slidably set inside the slide 17. The magnetic block 23 is fixedly installed on the lower surface of the movable sealing plate 16, and the side of the magnetic block 23 near the rotating shaft 18 is provided on the movable sealing plate 16. A base plate 21 is fixedly installed on the inner wall of the air inlet pipe 3, and the electromagnet 22 is fixedly installed on the upper surface of the base plate 21, and the electromagnet 22 is correspondingly set on the magnetic block. Directly below 23, when electromagnet 22 is energized, electromagnet 22 generates magnetism. The magnetic poles generated by electromagnet 22 repel the magnetic poles at the lower end of magnetic block 23. That is, when electromagnet 22 is energized, there is magnetic repulsion between electromagnet 22 and magnetic block 23, causing movable sealing plate 16 to move along the height direction of gas groove 14 to the upper end of gas groove 14. When electromagnet 22 is not energized, the magnetic interaction between electromagnet 22 and magnetic block 23 disappears, and movable sealing plate 16 slides along the height direction of gas groove 14 to the lower end of gas groove 14 due to gravity. First baffle 19 and second baffle 20 are respectively fixed on the inner wall of gas groove 14 away from slide 17, with first baffle 19 located at the upper end of gas groove 14 and second baffle 20 located at the lower end of gas groove 14.

[0026] When gas needs to enter the interior of housing 1 through the bottom of gas channel 14, electromagnet 22 does not need to be energized. At this time, the movable sealing plate 16 is located at the lower end of gas channel 14. When the gas pushes the movable sealing plate 16, the movable sealing plate 16 rotates along the rotating shaft 18 and opens upward. The gas enters the interior of housing 1 through gas channel 14. When gas is discharged outward from the top of gas channel 14, the movable sealing plate 16 is blocked by the second baffle 20 on the side away from the rotating shaft 18. The movable sealing plate 16 can only be pushed by the reverse flow of gas to close gas channel 14, thus avoiding gas backflow. When gas needs to be discharged from the housing 1 through the gas channel 14 and out through the air inlet pipe 3, the corresponding electromagnet 22 can be energized. At this time, the movable sealing plate 16 is located at the upper end of the gas channel 14. When the gas pushes the movable sealing plate 16, it causes the movable sealing plate 16 to rotate along the rotation shaft 18 and open downward to allow the gas to be discharged. When external gas wants to enter the housing 1 in the reverse direction through the gas channel 14, the gas will push the movable sealing plate 16 to rotate upward. Since the side of the movable sealing plate 16 away from the rotation shaft 18 is blocked by the first baffle 19, the movable sealing plate 16 will close the gas channel 14, avoiding interference from the backflow of external gas.

[0027] The small pump mechanism includes a pump body 9, which uses the Qihai Electromechanical C09 series, with dimensions of 32mm×22mm×37mm (length×width×height) and a flow rate of 0.5-1.2L / min (adjustable).

[0028] The pump body 9 is provided with an air inlet main pipe 11 and an air outlet pipe 10. The air outlet pipe 10 is directly opposite the top center of the housing 1. The air inlet main pipe 11 is provided with several air inlet auxiliary pipes 12. Each of the several air inlet auxiliary pipes 12 corresponds to one of the several probes 5. The air inlet auxiliary pipes 12 face the bottom of the probes 5. A solenoid valve 24 is provided in the air inlet auxiliary pipes 12.

[0029] When it is necessary to detect the methane content in a coal mine, a corresponding solenoid valve 24 can be opened to start the pump body 9. The gas in the coal mine passes through the inlet pipe 3, gas tank 14, lower chamber, filter cotton 8, upper chamber, auxiliary inlet pipe 12, main inlet pipe 11, and outlet pipe 10 in sequence before being discharged back into the upper chamber. During the process of the gas being drawn in by the auxiliary inlet pipe 12, it passes through the corresponding probe 5, which detects the methane content data in the gas. When the gas is discharged, it will be discharged from the remaining non-inlet pipes 3. When the gas passes through the filter cotton 8 from top to bottom, the dust adhering to the surface of the filter cotton 8 can be blown off and discharged from the inlet pipe 3. It can also clean the inside of the housing 1. That is, the present invention, through the setting of a small pump mechanism, filter components and gas reversing mechanism, can not only ensure that the detected gas is not affected by dust, but also can be self-maintained and cleaned, eliminating the need for frequent manual cleaning and greatly reducing the cost of use.

[0030] It should be noted that: in this invention, several probes 5 can simultaneously detect multiple content data in the gas. When it is necessary to keep at least one probe 5 inactive, at least one air inlet pipe 3 is left for exhaust.

[0031] Furthermore, in this invention, a curved metal sheet 15 is fixedly installed at the upper opening of the gas tank 14. When the gas passes around the curved metal sheet 15, it will cause the curved metal sheet 15 to vibrate. When the curved metal sheet 15 vibrates, it causes the surrounding gas to vibrate, thereby helping the dust adhering to the filter cotton 8 to fall off, making it less prone to clogging and highly practical.

[0032] It should also be noted that multiple vertical baffles 13 are provided in the lower chamber. The vertical baffles 13 are used to prevent the gas from mixing and interfering with the gas entering when it is discharged.

Claims

1. A device for detecting methane concentration in coal mines, characterized in that, include: The housing (1) is a rectangular box structure; A gas concentration detector (2) is installed above the housing (1) and its detection end (4) extends into the housing (1). Multiple probes (5) are installed on the top wall inside the housing (1). The multiple probes (5) are connected to the detection end (4) via an RS485 bus (6). The air intake pipe (3) is provided in multiple ways. The air intake pipe (3) is fixed to the bottom of the housing (1). The multiple air intake pipes (3) are respectively provided below each probe (5). The housing (1) is equipped with a small pump mechanism inside, which is used to draw gas from the air inlet pipe (3) and make the gas act around the corresponding probe (5). The housing (1) is equipped with a filter assembly between the probe (5) and the air inlet pipe (3) for filtering dust in the gas. The bottom of the housing (1) is equipped with a gas groove (14) that connects the air inlet pipe (3) and the inside of the housing (1). The gas groove (14) is equipped with a gas reversing mechanism.

2. The device for detecting methane concentration in coal mines according to claim 1, characterized in that: The small pump mechanism includes a pump body (9), an air inlet main pipe (11) and an air outlet pipe (10). The air inlet main pipe (11) is provided with multiple air inlet auxiliary pipes (12). The multiple air inlet auxiliary pipes (12) correspond one-to-one with the multiple probes (5). The air inlet auxiliary pipes (12) are provided with solenoid valves (24).

3. The device for detecting methane concentration in coal mines according to claim 1, characterized in that: Multiple probes (5) include a catalytic combustion probe, a first electrochemical probe, a second electrochemical probe, a paramagnetic / galvanic probe, a carbon dioxide detection probe, and a temperature detection probe, which are used to detect the concentrations of methane, carbon monoxide, hydrogen sulfide, oxygen, carbon dioxide, and ambient temperature, respectively.

4. The device for detecting methane concentration in coal mines according to claim 1, characterized in that: The filter assembly includes a transverse partition (7) and a filter cotton (8). The transverse partition (7) is horizontally fixed inside the housing (1) and isolates the inside of the housing (1) into upper and lower chambers. The transverse partition (7) is provided with multiple rectangular grooves. The filter cotton (8) is installed in the rectangular grooves. The number of rectangular grooves corresponds to the number of probes (5) and is located between the probes (5) and the corresponding air inlet pipes (3). The small pump mechanism is located in the upper chamber.

5. The device for detecting methane concentration in coal mines according to claim 1, characterized in that: The gas reversing mechanism includes a movable sealing plate (16), a slide groove (17), a rotating shaft (18), an electromagnet (22), a magnetic block (23), a first baffle (19), and a second baffle (20). The slide groove (17) is arranged along the height direction of the gas groove (14) at its edge. The movable sealing plate (16) is horizontally arranged and movably placed in the gas groove (14). One side of the movable sealing plate (16) is rotatably set through the rotating shaft (18). The end of the rotating shaft (18) is slidably set inside the slide groove (17). The magnetic block... (23) is fixedly installed on the lower surface of the movable sealing plate (16) and close to the rotating shaft (18). The inner wall of the air inlet pipe (3) is fixed with a base plate (21). The electromagnet (22) is fixedly installed on the upper surface of the base plate (21) and is correspondingly arranged directly below the magnetic block (23). The first baffle (19) and the second baffle (20) are respectively fixed on the inner wall of the gas groove (14) away from the slide groove (17). The first baffle (19) is located at the upper end of the gas groove (14), and the second baffle (20) is located at the lower end of the gas groove (14).

6. The device for detecting methane concentration in coal mines according to claim 2, characterized in that: The exhaust pipe (10) is located at the top center of the housing (1), and the intake auxiliary pipe (12) faces the bottom of the corresponding probe (5).

7. The device for detecting methane concentration in coal mines according to claim 1, characterized in that: A bent metal sheet (15) is fixedly installed at the upper opening of the gas tank (14) to generate vibration when the gas flows through, so as to help remove the dust adhering to the filter cotton (8).

8. The device for detecting methane concentration in coal mines according to claim 3, characterized in that: The lower chamber is provided with multiple vertical partitions (13), which are located between adjacent air inlet pipes (3).

9. The device for detecting methane concentration in coal mines according to claim 1, characterized in that: The housing (1) is assembled from upper and lower box bodies, and at least one probe (5) is not in operation so that at least one air inlet pipe (3) is left for exhaust.

10. The device for detecting methane concentration in coal mines according to claim 1, characterized in that: Multiple probes (5) are used to detect various contents in the gas. The detection results are transmitted to the gas concentration detector (2) via RS485 bus (6). The gas concentration detector (2) is equipped with an audible and visual alarm to warn coal mine workers.

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