Electrical switching unit and novel methane monitoring system applied by electrical switching unit and used for coal mine fan drift

Abstract

The invention relates to an electrical switching unit and a novel methane monitoring system applied by the electrical switching unit and used for a coal mine fan drift. In order to overcome the defects in the prior art, the electrical switching unit comprises a differential pressure transducer, a two-position three-way electromagnetic valve, two pitot tubes, a first two-position five-way pneumatic reversing valve, a second two-position five-way pneumatic reversing valve, a third two-position five-way pneumatic reversing valve and a fourth two-position five-way pneumatic reversing valve, and (R and S) interfaces of the first two-position five-way pneumatic reversing valve are respectively communicated with (A and B) interfaces of the third two-position five-way pneumatic reversing valve; interfaces (R and S) of the second two-position five-way pneumatic reversing valve are respectively communicated with interfaces (A and B) of the fourth two-position five-way pneumatic reversing valve, interfaces (A and B) of the first two-position five-way pneumatic reversing valve are respectively communicated with total pressure tubes of the two pitot tubes, and two interfaces of the differential pressure sensor are respectively connected with interfaces (P) of the third two-position five-way pneumatic reversing valve and the fourth two-position five-way pneumatic reversing valve. The device is compact in structure and suitable for being used in a coal mine exhaust shaft fan drift.

Description

Technical Field

[0001] This invention relates to a novel methane monitoring system for coal mine ventilation shafts, which includes an electrical switching unit and its application. Background Technology

[0002] Chinese invention patent document CN102680031B, with an authorization announcement date of May 21, 2014, discloses a method for measuring the air volume of a blower based on static pressure difference, comprising the following steps: First, taking two pressure measuring points, a first pressure measuring point S1 and a second pressure measuring point S2, at the roadway and the blower inlet, respectively; Second, measuring the static pressure values ​​at the first pressure measuring point S1 and the second pressure measuring point S2, respectively; Third, calculating the air volume according to a set formula. This invention has good versatility and can be applied to the measurement of air volume for all blower detection or online monitoring. It offers high measurement accuracy, convenient installation, and easy operation. The first pressure measuring point S1 is taken from a U-shaped gauge installed in the mine, which is connected to a roadway air pressure measuring device, and the Pitot tube of the U-shaped gauge is connected to a pressure sensor; the second pressure measuring point S2 is taken from an annular pressure measuring device on the inlet body of the blower.

[0003] Chinese invention patent application CN 107859527 A, published on March 30, 2018, discloses a mine pressure and air measurement device and method thereof, belonging to the field of coal mining. The technical solution adopted is as follows: the main shaft pressure measurement device includes a negative pressure measuring tube, a total pressure measuring tube, and a static pressure measuring tube. The negative pressure measuring tube and the total pressure measuring tube are installed in a straight-section air duct with a square cross-section connecting the main shaft. The pressure measuring hole opening direction of the negative pressure measuring tube is perpendicular to the airflow, and the pressure measuring hole opening direction of the total pressure measuring tube is parallel to the airflow. The negative pressure measuring tube and the total pressure measuring tube are respectively connected to a U-shaped differential pressure gauge. The static pressure measuring tube is installed in the straight section in front of the ventilator of the circular air duct connecting the square-section air duct. The static pressure measuring tube is connected to the U-shaped differential pressure gauge, and the pressure measuring hole opening of the static pressure measuring tube is perpendicular to the airflow.

[0004] Chinese utility model patent CN 206975067U, with an authorization announcement date of February 6, 2018, discloses a micro-differential pressure anemometer system. This system relates to a device for measuring fluid velocity, aiming to overcome the problem that handheld anemometers cannot measure the wind speed at the upper part of underground tunnels due to their large cross-sections, thus causing significant errors. The system consists of an anemometer, a support rod, and Pitot tubes. The support rod is a telescopic straight rod, with one or more Pitot tubes fixed to its body via Pitot tube holders. All Pitot tube inlets are aligned on the same straight line. The total pressure outlets of all Pitot tubes are connected to the high-pressure interface of a micro-differential pressure sensor via total pressure hoses, and the static pressure outlets of all Pitot tubes are connected to the low-pressure interface of the micro-differential pressure sensor via static pressure hoses.

[0005] In the coal mining industry, a ventilation shaft usually refers to a connecting roadway between the mine's return air shaft and the main ventilation fan. Because the air volume and the pressure difference between the inside and outside of the ventilation shaft are relatively large, special attention should be paid to reducing the ventilation resistance and minimizing air leakage.

[0006] The publication date is November 24, 2023, and the publication number is CN 117110244. Chinese invention patent application A discloses a methane emission monitoring system for coal mine ventilation shafts. The system includes: a precise ventilation shaft airflow measurement component for accurately measuring relevant airflow parameters of the ventilation shaft; a precise ventilation shaft methane concentration measurement component for accurately measuring relevant methane concentration parameters of the ventilation shaft, including a temperature and humidity sensor, a sampler, a methane monitoring transmission pipeline, a mechanical water filtration and dust removal conversion device, an air pump, a tunable laser spectroscopy (TDLAS) gas detector, a pressure transmission pipeline, a wall outlet device, a pressure sensor switching device, a ventilation shaft pressure sensor, and signal cables; and a ventilation shaft methane emission integration component for collecting, analyzing, and processing airflow velocity, methane concentration, temperature, humidity, and atmospheric pressure within the ventilation shaft to calculate the methane emission amount.

[0007] The above patents measure the hydrostatic difference generated by the wind speed in the ventilation shaft using multiple Pitot tubes and differential pressure sensors to measure the wind speed. During use, some differential pressure sensors may experience large changes in their readings over a short period. In such cases, it is necessary to disassemble and purge the Pitot tubes, the full-pressure hose, and the differential pressure sensors to restore normal operation. This process involves complex pipeline connections, tedious disassembly and inspection, and is prone to confusion.

[0008] Methane is the second largest greenhouse gas after carbon dioxide and a precursor to tropospheric ozone. The coal industry accounts for the largest share of methane emissions. Currently, my country's methane control system mainly measures the exhaust volume of coal mine return air shafts or main ventilation fans and calculates the methane content in the mine air online, thus determining the methane emissions of each coal mine. With the development and increasing needs of environmental protection, national environmental protection departments will inevitably need to include the methane emissions of each coal mine in their monitoring. There is an urgent need for new systems and technologies for monitoring total coal mine exhaust volume and methane emissions. Summary of the Invention

[0009] The technical problem to be solved by the present invention is how to overcome the above-mentioned defects of the prior art and provide a novel methane monitoring system for coal mine ventilation shafts, which is suitable for switching and assembly of electrical switching units and their applications.

[0010] To solve the above-mentioned technical problems, the electrical switching unit of the present invention includes a differential pressure sensor 1, a two-position three-way solenoid valve 2, two Pitot tubes 3, a first two-position five-way pneumatic directional valve 4, a second two-position five-way pneumatic directional valve 5, a third two-position five-way pneumatic directional valve 6, and a fourth two-position five-way pneumatic directional valve 7. Each Pitot tube 3 includes a total pressure tube 31 and a static pressure tube 32. The differential pressure sensor 1 is provided with two interfaces. The two-position three-way solenoid valve 2 is provided with three interfaces P, R, and A. All two-position five-way pneumatic directional valves are provided with five interfaces A, B, R, P, S, a left pneumatic control interface 8, and a right pneumatic control interface 9.

[0011] The R and S ports of the first two-position five-way pneumatic directional valve 4 are connected to the A and B ports of the third two-position five-way pneumatic directional valve 6 via pipeline 10, respectively. The R and S ports of the second two-position five-way pneumatic directional valve 5 are connected to the A and B ports of the fourth two-position five-way pneumatic directional valve 7 via pipeline 10, respectively.

[0012] The A and B ports of the first two-position five-way pneumatic directional valve 4 are respectively connected to the total pressure pipes 31 of the two Pitot tubes 3 via pipeline 10. The A and B ports of the second two-position five-way pneumatic directional valve 5 are respectively connected to the static pressure pipes 32 of the two Pitot tubes 3 via pipeline 10. The two ports of the differential pressure sensor 1 are respectively connected to the P ports of the third two-position five-way pneumatic directional valve 6 and the fourth two-position five-way pneumatic directional valve 7 via pipeline 10.

[0013] The P port of the first two-position five-way pneumatic directional valve 4 and the P port of the second two-position five-way pneumatic directional valve 5 are connected to the A port of the two-position three-way solenoid valve 2 via the purge line 20. This design allows each electrical switching unit to be self-contained, assembled and maintained independently, preventing confusion. During use, an appropriate number of electrical switching units can be selected based on the cross-sectional size of the ventilation shaft to form a novel methane monitoring system for coal mine ventilation shafts. This system is easy to assemble and maintain.

[0014] As an optimization, all Pitot tubes 3 are S-shaped and used upside down. This design prevents moisture from condensing on the Pitot tube and entering it, making it suitable for wind measurement in coal mine ventilation shafts.

[0015] This novel methane monitoring system for coal mine ventilation shafts includes a methane concentration detection device for the ventilation shaft. It is used with a mine ventilation shaft 11 and has two branch ventilation shafts 12. Each branch ventilation shaft 12 is equipped with an air door 13 and a support frame 14 (Note: Each branch ventilation shaft has a main ventilator installed at its outer end, not shown in the figure, omitted). The methane concentration detection device includes a sampling tube, a tunable laser spectroscopy (TDLAS) gas detector, and a suction pump. It also includes an electric air pump 15, a two-position five-way electromagnetic reversing valve 16, and N of the aforementioned electrical switching units. The two-position five-way electromagnetic reversing valve 16 has five interfaces: A, B, R, P, and S. The two pitot tubes 3 of each electrical switching unit are vertically fixed at the same position on the two support frames 14, with their probes facing downwards.

[0016] The left pneumatic control interface 8 of the first two-position five-way pneumatic directional valve 4, the left pneumatic control interface 8 of the second two-position five-way pneumatic directional valve 5, the right pneumatic control interface 9 of the third two-position five-way pneumatic directional valve 6, and the right pneumatic control interface 9 of the fourth two-position five-way pneumatic directional valve 7 of all electrical switching units are connected to the first air supply pipe 17; the right pneumatic control interface 9 of the first two-position five-way pneumatic directional valve 4, the right pneumatic control interface 9 of the second two-position five-way pneumatic directional valve 5, the left pneumatic control interface 8 of the third two-position five-way pneumatic directional valve 6, and the right pneumatic control interface 9 of the fourth two-position five-way pneumatic directional valve 7 of all electrical switching units are connected to the first air supply pipe 17; The left pneumatic control interface 8 of the five-way pneumatic directional valve 7 is connected to the second air supply pipe 18. The first air supply pipe 17 and the second air supply pipe 18 are connected to the A and B interfaces of the two-position five-way solenoid directional valve 16, respectively. The P interface of the two-position three-way solenoid valve 2 of all electrical switching units and the P interface of the two-position five-way solenoid directional valve 16 are connected to the outlet of the electric air pump 15 through the pipeline 10, where N is a positive integer and 6≤N≤25. The location of the support frame 14 is the wind tunnel measurement point. When the distance between the wind tunnel measurement point and the bend or facility is 10 times the hydraulic diameter, N takes the minimum value. The hydraulic diameter is the ratio of four times the cross-sectional area to the perimeter.

[0017] In this design, the two Pitot tubes in each electrical switching unit are installed in the same position on the two support frames 14, one for online use and one for standby. When switching between the two ventilation shafts, the online use of the Pitot tubes in the two ventilation shafts can be switched by operating the two-position five-way solenoid reversing valve 16 when switching the corresponding damper and main ventilator. Figure 3 , 5 As shown.

[0018] Opening the two-position three-way solenoid valve 2 of a certain electrical switching unit can also purge the pitot tube in the standby state of that electrical switching unit, such as... Figure 4 As shown.

[0019] When the reading of a pitot tube used online exceeds the application value of the pitot tube at its measuring point by more than 10%, it usually indicates that the pitot tube needs to be calibrated promptly. The usual procedure is to disconnect the pitot tube from the pipeline, zero the pressure regulator, connect a tee to the compensating chamber barometer, and compare the measured values ​​with the differential pressure sensor readings within the specified range. If the reading is acceptable, the pitot tube can be put into use. If it fails, the pitot tube's measurement value should be discarded and addressed during maintenance.

[0020] Using this invention, a two-position five-way solenoid directional valve 16 can be operated, such as... Figure 5 As shown, an online switching operation is performed. At this time, all Pitot tubes in the standby air distribution chamber are switched to online status, but there is no airflow through the standby air distribution chamber. The differential pressure detected by the differential pressure sensor 1 of each electrical switching unit should be 0 (or if a differential pressure sensor 1 is not 0, it indicates a fault in that sensor 1). Simultaneously, all Pitot tubes in the air distribution chambers where airflow still occurs are switched to standby status. The two-position three-way solenoid valve connected to the previously faulty Pitot tube is opened, and the Pitot tube is purged for 2-3 minutes. Then, the two-position five-way solenoid valve 16 is operated again to perform the online switching, as shown... Figure 3 As shown. At this point, the problematic pitot tube will return to normal. The switching operation is simple and does not require changing the on / off status of the two ventilation shafts.

[0021] As an optimization, all two-position three-way solenoid valves 2 are two-position three-way single-control normally closed solenoid valves. With this design, they always remain in the normal position (closed state) and do not work unless an electrical signal is supplied. An electrical signal is only required to output to the corresponding two-position three-way solenoid valve when purging a certain Pitot tube, which saves power and is reliable.

[0022] As an optimization, all two-position five-way pneumatic directional valves 4, 5, 6, and 7 are two-position five-way double-control double-stable non-constant-position pneumatic directional valves. With this design, in the absence of significant vibration or shaking, the valve can maintain its operating state before the gas supply is stopped, and the electric air pump can remain inactive if the valve is not switched for an extended period.

[0023] As an optimization, the two-position five-way solenoid directional valve 16 is a two-position five-way dual-control bi-stable non-constant-position solenoid directional valve. With this design, under conditions without significant vibration or shaking, it can maintain its working state before the power outage during a power failure. When not switching for a long time, the two-position five-way solenoid directional valve can be de-energized, saving energy and ensuring reliability.

[0024] As an optimization, a dust extraction and water removal filter device 19 (such as the dust extraction and water removal filter device disclosed in CN219353768U) is also connected in series at the inlet of the electric air pump 15. This design can prevent moisture and dust from entering the system and affecting the detection accuracy and valve operation.

[0025] The electrical switching unit of this invention and its application in a novel methane monitoring system for coal mine ventilation shafts are compact in structure and suitable for use in coal mine exhaust shafts. Attached Figure Description

[0026] The following description, in conjunction with the accompanying drawings, further illustrates this electrical switching unit and its application in a novel methane monitoring system for coal mine ventilation shafts: Figure 1 This is a schematic diagram of the structure of this electrical switching unit; Figure 2 This is a three-dimensional structural diagram of the methane monitoring system for coal mine ventilation shafts, along with the ventilation shaft, air doors, and support frame (the arrows in the diagram indicate the airflow direction). Figure 3 This is a schematic diagram of the flow structure of N electrical switching units, electric air pumps, and two-position five-way electromagnetic reversing valves in the methane monitoring system for coal mine ventilation shafts (the diagram shows the first and Nth electrical switching units, and the six dots represent omitted intermediate electrical switching units. In each electrical switching unit, the left Pitot tube is on standby (dashed line), and the right Pitot tube is used for online monitoring (solid line)). Figure 4 yes Figure 3 The diagram shows the process structure of the new coal mine ventilation shaft methane monitoring system purging the Pitot tube of the first electrical switching unit on the left. Figure 5 yes Figure 3 The diagram shows the process structure of the new coal mine ventilation shaft methane monitoring system after switching (the left Pitot tube in each electrical switching unit is for online monitoring (solid line)), and the right Pitot tube is for standby (dashed line)).

[0027] In the diagram: 1 is a differential pressure sensor, 2 is a two-position three-way solenoid valve (with P, R, and A ports), 3 is a Pitot tube, 31 is the total pressure line, and 32 is the static pressure line. 4 is the first two-position five-way pneumatic directional valve, 5 is the second two-position five-way pneumatic directional valve, 6 is the third two-position five-way pneumatic directional valve, 7 is the fourth two-position five-way pneumatic directional valve (including five ports: A, B, R, P, and S), 8 is the left pneumatic control port of each two-position five-way pneumatic directional valve, and 9 is the right pneumatic control port of each two-position five-way pneumatic directional valve. 10 is the pipeline, 11 is the supporting mine ventilation shaft, 12 is the branch ventilation shaft, 13 is the air door, 14 is the support frame, 15 is the electric air pump, 16 is the two-position five-way solenoid directional valve (including five interfaces: A, B, R, P, and S), 17 is the first air supply pipe, 18 is the second air supply pipe, 19 is the dust collection and water removal filtration device, and 20 is the purging pipeline. Detailed Implementation

[0028] Implementation method one: such as Figure 1As shown, the electrical switching unit of the present invention includes a differential pressure sensor 1, a two-position three-way solenoid valve 2, two pitot tubes 3, a first two-position five-way pneumatic directional valve 4, a second two-position five-way pneumatic directional valve 5, a third two-position five-way pneumatic directional valve 6, and a fourth two-position five-way pneumatic directional valve 7. Each pitot tube 3 includes a total pressure tube 31 and a static pressure tube 32. The differential pressure sensor 1 has two interfaces. The two-position three-way solenoid valve 2 has three interfaces: P, R, and A. All two-position five-way pneumatic directional valves (including the first two-position five-way pneumatic directional valve 4, the second two-position five-way pneumatic directional valve 5, the third two-position five-way pneumatic directional valve 6, and the fourth two-position five-way pneumatic directional valve 7) have five interfaces: A, B, R, P, S, a left-side pneumatic control interface 8, and a right-side pneumatic control interface 9. The R and S ports of the first two-position five-way pneumatic directional valve 4 are connected to the A and B ports of the third two-position five-way pneumatic directional valve 6 via pipeline 10, respectively. The R and S ports of the second two-position five-way pneumatic directional valve 5 are connected to the A and B ports of the fourth two-position five-way pneumatic directional valve 7 via pipeline 10, respectively. The A and B ports of the first two-position five-way pneumatic directional valve 4 are respectively connected to the total pressure pipes 31 of the two Pitot tubes 3 via pipeline 10. The A and B ports of the second two-position five-way pneumatic directional valve 5 are respectively connected to the static pressure pipes 32 of the two Pitot tubes 3 via pipeline 10. The two ports of the differential pressure sensor 1 are respectively connected to the P ports of the third two-position five-way pneumatic directional valve 6 and the fourth two-position five-way pneumatic directional valve 7 via pipeline 10. The P port of the first two-position five-way pneumatic directional valve 4 and the P port of the second two-position five-way pneumatic directional valve 5 are connected to the A port of the two-position three-way solenoid valve 2 via the purge line 20. All Pitot tubes 3 are S-type Pitot tubes, used upside down.

[0029] Implementation method one: such as Figure 2-5 As shown, this novel methane monitoring system for coal mine ventilation shafts includes a methane concentration detection device. It is used with a mine ventilation shaft 11 and has two branch ventilation shafts 12. Each branch ventilation shaft 12 is equipped with an air damper 13 and a support frame 14. The methane concentration detection device includes a sampling tube (not shown), a tunable laser spectroscopy (TDLAS) gas detector (not shown), and a suction pump (not shown). One end of the sampling tube is inserted into the housing of the main ventilation fan, and the other end is connected to the inlet of the suction pump. The tunable laser spectroscopy (TDLAS) gas detector is connected in series with the sampling tube. The system is characterized by further including an electric air pump 15, a two-position five-way solenoid valve 16, and N of the aforementioned electrical switching units. The two-position five-way solenoid valve 16 has five interfaces A, B, R, and P. In each electrical switching unit, two pitot tubes 3 are vertically fixed at the same position on two support frames 14, with their probes facing downwards. The left pneumatic control interface 8 of the first two-position five-way pneumatic directional valve 4, the left pneumatic control interface 8 of the second two-position five-way pneumatic directional valve 5, the right pneumatic control interface 9 of the third two-position five-way pneumatic directional valve 6, and the right pneumatic control interface 9 of the fourth two-position five-way pneumatic directional valve 7 of all electrical switching units are connected to the first air supply pipe 17; the right pneumatic control interface 8 of the first two-position five-way pneumatic directional valve 4, the right pneumatic control interface 8 of the second two-position five-way pneumatic directional valve 5, the right pneumatic control interface 9 of the third two-position five-way pneumatic directional valve 6, and the right pneumatic control interface 9 of the fourth two-position five-way pneumatic directional valve 7 of all electrical switching units are connected to the first air supply pipe 17; The left pneumatic control interface 8 of the five-way pneumatic directional valve 6 and the left pneumatic control interface 8 of the fourth two-way five-way pneumatic directional valve 7 are both connected to the second air supply pipe 18. The first air supply pipe 17 and the second air supply pipe 18 are respectively connected to the A and B interfaces of the two-way five-way solenoid directional valve 16. The P interface of the two-way three-way solenoid valve 2 of all electrical switching units and the P interface of the two-way five-way solenoid directional valve 16 are respectively connected to the outlet of the electric air pump 15 through the pipeline 10. N is a positive integer and 9≤N≤25.

[0030] All two-position three-way solenoid valves 2 are two-position three-way single-control normally closed solenoid valves. All two-position five-way pneumatic directional valves 4, 5, 6, and 7 are two-position five-way double-control bistable non-constant-position pneumatic directional valves. The two-position five-way solenoid directional valve 16 is a two-position five-way double-control bistable non-constant-position solenoid directional valve; all are existing products, mainly available on the market.

[0031] Implementation Method Two: (e.g.) Figure 3-5 As shown, a dust suction and water removal filter device 19 is also connected in series at the inlet of the electric air pump 15. The rest of the structure is as shown in Embodiment 1, and is omitted.

Claims

1. An electrical switching unit, characterized by: It comprises a differential pressure sensor (1), a two-position three-way electromagnetic valve (2), two pitot tubes (3), a first two-position five-way pneumatic reversing valve (4), a second two-position five-way pneumatic reversing valve (5), a third two-position five-way pneumatic reversing valve (6) and a fourth two-position five-way pneumatic reversing valve (7), each pitot tube (3) comprises a total pressure tube (31) and a static pressure tube (32), the differential pressure sensor (1) is provided with two interfaces, the two-position three-way electromagnetic valve (2) is provided with three interfaces (P, R, A), all the two-position five-way pneumatic reversing valves are provided with five interfaces (A, B, R, P, S), a left pneumatic control interface (8) and a right pneumatic control interface (9), The (R, S) interfaces of the first two-position five-way pneumatic reversing valve (4) are communicated with the (A, B) interfaces of the third two-position five-way pneumatic reversing valve (6) through pipelines (10) respectively, the (R, S) interfaces of the second two-position five-way pneumatic reversing valve (5) are communicated with the (A, B) interfaces of the fourth two-position five-way pneumatic reversing valve (7) through pipelines (10) respectively, The (A, B) interfaces of the first two-position five-way pneumatic reversing valve (4) are communicated with the total pressure tubes (31) of the two pitot tubes (3) through pipelines (10) respectively, the (A, B) interfaces of the second two-position five-way pneumatic reversing valve (5) are communicated with the static pressure tubes (32) of the two pitot tubes (3) through pipelines (10) respectively, the two interfaces of the differential pressure sensor (1) are connected with the (P) interfaces of the third two-position five-way pneumatic reversing valve (6) and the fourth two-position five-way pneumatic reversing valve (7) through pipelines (10) respectively, The (P) interface of the first two-position five-way pneumatic reversing valve (4) and the (P) interface of the second two-position five-way pneumatic reversing valve (5) are connected with the (A) interface of the two-position three-way electromagnetic valve (2) through a purge pipeline (20) together.

2. The electrical switching unit according to claim 1, characterized in that: All the pitot tubes (3) are S-shaped pitot tubes and are used upside down.

3. A novel methane monitoring system for mine air shafts, comprising an air shaft methane concentration detection device, wherein the mine air shaft (11) is provided with two branch air shafts (12), each branch air shaft (12) is provided with an air door (13) and a support frame (14), and the air shaft methane concentration detection device comprises a sampling pipe, a tunable diode laser absorption spectroscopy (TDLAS) gas detector and an air pump, characterized in that: It further comprises an electric air pump (15), a two-position five-way electromagnetic reversing valve (16) and N electric switching units according to claim 1 or 2, the two-position five-way electromagnetic reversing valve (16) is provided with five interfaces (A, B, R, P, S), the two pitot tubes (3) of each electric switching unit are vertically fixed at the same position of two support frames (14) respectively, and the probe parts thereof are downward. The left pneumatic control interface (8) of the first two-position five-way pneumatic reversing valve (4), the left pneumatic control interface (8) of the second two-position five-way pneumatic reversing valve (5), the right pneumatic control interface (9) of the third two-position five-way pneumatic reversing valve (6) and the right pneumatic control interface (9) of the fourth two-position five-way pneumatic reversing valve (7) of all the electrical switching units are communicated with the first gas supply pipe (17); the right pneumatic control interface (9) of the first two-position five-way pneumatic reversing valve (4), the right pneumatic control interface (9) of the second two-position five-way pneumatic reversing valve (5), the left pneumatic control interface (8) of the third two-position five-way pneumatic reversing valve (6) and the left pneumatic control interface (8) of the fourth two-position five-way pneumatic reversing valve (7) of all the electrical switching units are communicated with the second gas supply pipe (18), the first gas supply pipe (17) and the second gas supply pipe (18) are respectively communicated with the (A, B) interface of the two-position five-way electromagnetic reversing valve (16), the (P) interface of the two-position three-way electromagnetic valve (2) and the (P) interface of the two-position five-way electromagnetic reversing valve (16) of all the electrical switching units are respectively communicated with the outlet of the electric air pump (15) through the pipeline (10), wherein N is a positive integer, and 6≤N≤25.

4. The novel methane monitoring system for coal mine air shafts according to claim 3, characterized in that: All the two-position three-way electromagnetic valves (2) are two-position three-way single-control normally closed electromagnetic valves.

5. The novel methane monitoring system for coal mine air shafts according to claim 3, characterized in that: All the two-position five-way pneumatic reversing valves (4, 5, 6, 7) are two-position five-way double-control double-stable no-constant-position pneumatic reversing valves.

6. The novel methane monitoring system for coal mine air shafts according to claim 3, characterized in that: The two-position five-way electromagnetic reversing valve (16) is a two-position five-way double-control double-stable no-constant-position electromagnetic reversing valve.

7. The novel methane monitoring system for coal mine air shafts according to claim 3, characterized in that: The electric air pump (15) inlet is also connected with the dust suction and water removal filter device (19).

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