Monitoring, early warning, prevention and control system and method for closed goaf of coal mine

Abstract

The invention discloses a coal mine closed goaf monitoring, early warning, prevention and control system and method, and the system comprises a multi-parameter sensing device which is connected with a closed goaf and is used for monitoring the internal environment state of the closed goaf in real time; the multi-parameter sensing device is connected with the monitoring substation, the monitoring substation is connected with the data conversion and transmission equipment, the data conversion and transmission equipment is connected with the closed monitoring host, and the closed monitoring host is used for performing early warning on the internal state change of the closed goaf; the closed goaf is further connected with an anti-explosion electric control ball valve, and opening and closing of the anti-explosion electric control ball valve are controlled by a control instruction of a closed monitoring host on the ground. The anti-explosion electric control ball valve is installed on a branch pipeline of the underground nitrogen injection main pipeline, and the branch pipeline is connected to a measure hole used for monitoring a closed goaf. The problems of large underground sampling ground test error, low efficiency, poor timeliness and the like can be solved, and pre-disaster monitoring, in-disaster early warning and disaster prevention and control of the closed goaf of the coal mine are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of monitoring closed goaf areas in coal mines, and in particular relates to a monitoring, early warning and control system and method for closed goaf areas in coal mines. Background Art

[0002] Air leakage from the closed goaf of a coal mine to the external tunnels will cause excessive concentrations of harmful gases such as methane in the air of the external tunnels, seriously affecting the safety of workers. In addition, the infiltration of air into the closed goaf increases the risk of spontaneous combustion of the remaining coal in the closed goaf.

[0003] Although the closed goaf is isolated from the mine ventilation system, it cannot completely block the connection with the outside air. Changes in external air pressure will cause changes in the gas in the goaf. The ambient atmospheric pressure decreases with increasing altitude. The temperature difference between day and night will also cause changes in atmospheric pressure. Seasonal changes will also cause changes in atmospheric pressure, such as higher air pressure in winter than in summer. Gas outbursts from coal pillars, surrounding rocks, and adjacent layers in the closed goaf will cause a large amount of gas to accumulate inside the closed goaf. When the concentration of methane outflowing from the closed goaf to the external tunnel is too high, it will pose a serious threat to the personal safety of underground workers. At the same time, the fresh air flowing into the closed goaf will greatly increase the possibility of spontaneous combustion of the coal left inside the goaf.

[0004] At present, the daily monitoring method for closed goaf includes: coal mine inspectors carry portable analyzers for underground monitoring, and collect gas for analysis by ground gas chromatography. This method consumes manpower and material resources, is cumbersome to operate, and has a large workload. As a result, this method of underground sampling and ground testing has problems such as large errors, low efficiency, and poor timeliness, and it is impossible to form a closed goaf monitoring, early warning, and prevention and control management system. Therefore, it is necessary to propose a coal mine closed goaf monitoring, early warning, and prevention and control system and method. Summary of the invention

[0005] The present invention aims at the above-mentioned problems, makes up for the deficiencies of the prior art, and provides a monitoring, early warning and control system and method for closed goaf areas in coal mines.

[0006] To achieve the above object, the present invention adopts the following technical solution.

[0007] A monitoring, early warning and control system for a closed goaf area in a coal mine, comprising a multi-parameter sensor device, the multi-parameter sensor device being connected to the closed goaf area, the multi-parameter sensor device being used to monitor the internal environmental state of the closed goaf area in real time; the multi-parameter sensor device being communicatively connected to a monitoring substation, the monitoring substation being communicatively connected to a data conversion and transmission device, the data conversion and transmission device being communicatively connected to a closed monitoring host, the closed monitoring host being used to give an early warning of changes in the internal state of the closed goaf area; wherein the closed goaf area, the multi-parameter sensor device, the monitoring substation and the data conversion and transmission device are all arranged underground, the closed monitoring host being arranged Placed on the ground outside the well, the closed monitoring host is connected to the data conversion and transmission equipment through an underground ring network communication connection; the closed goaf is also connected to an explosion-proof electric-controlled ball valve, and the opening and closing of the explosion-proof electric-controlled ball valve are controlled by the control command of the closed monitoring host on the ground; when the warning value is exceeded, the closed monitoring host sends an opening control command to open the explosion-proof electric-controlled ball valve, and when the warning is lifted and the data drops to a safe range, the closed monitoring host sends a closing control command to close the explosion-proof electric-controlled ball valve; the explosion-proof electric-controlled ball valve is installed on a branch pipeline of the underground nitrogen injection main pipeline, and the branch pipeline is connected to the measure hole for monitoring the closed goaf.

[0008] Furthermore, the multi-parameter sensing device includes a gas concentration monitoring unit, a temperature and pressure difference monitoring unit, a micro-circulation air pump, an embedded data processing unit, an LCD display device unit, and a data communication interface unit. The gas concentration monitoring unit and the temperature and pressure difference monitoring unit are respectively connected to the signal input end of the embedded data processing unit, the micro-circulation air pump and the LCD display device unit are respectively connected to the signal output end of the embedded data processing unit, and the data communication interface unit is connected to the communication port of the embedded data processing unit; the multi-parameter sensing device is connected to the monitoring substation through the data communication interface unit.

[0009] Furthermore, the gas concentration monitoring unit includes an O2 sensor, a CH4 sensor, a CO2 sensor, and a CO sensor; wherein the O2 sensor adopts an electrochemical sensor, and the CH4 sensor, the CO2 sensor, and the CO sensor all adopt NDIR non-dispersive infrared principle detection technology to monitor the concentrations of CH4, CO2, and CO.

[0010] Furthermore, the temperature and pressure difference monitoring unit includes a pressure difference sensor and a PT100 temperature sensor.

[0011] Furthermore, the micro-circulating air pump is connected to the enclosed goaf through a bundle pipe, and a dust removal and water filter is arranged on the bundle pipe between the micro-circulating air pump and the enclosed goaf, and the dust removal and water filter is provided with three-level filtering protection.

[0012] Furthermore, the monitoring substation adopts 24VDC intrinsically safe power supply and is equipped with an LCD screen for displaying the online and offline, power supply and operating status of the equipment.

[0013] Furthermore, the multi-parameter sensing device, monitoring substation, data conversion and transmission equipment, and explosion-proof electric-controlled ball valve are all powered by a power supply box.

[0014] Furthermore, the enclosed monitoring host is also connected to a printer, and the enclosed monitoring host is connected to the Internet of Things cloud platform through the Internet of Things module.

[0015] A method for monitoring, early warning and controlling a closed goaf area in a coal mine is implemented by using the above-mentioned monitoring, early warning and controlling system for a closed goaf area in a coal mine, and comprises the following steps:

[0016] The closed monitoring host issues nitrogen injection and grouting prevention and control instructions according to the warning value, and the explosion-proof electric control ball valve opens 20%, 40%, 60%, 80%, and 100% of the opening corresponding to the five-level warning respectively. When the warning returns to a safe state, the explosion-proof electric control ball valve is automatically closed;

[0017] The closed monitoring host injects nitrogen according to the internal and external pressure difference of the closed goaf monitored by the multi-parameter sensor device to ensure that the closed goaf is at a slightly positive pressure; when the internal-external pressure difference is less than 0Pa, the system issues a nitrogen injection command to open the explosion-proof electric-controlled ball valve; when the internal-external pressure difference is greater than 2Pa, the system issues a nitrogen injection command to close the explosion-proof electric-controlled ball valve;

[0018] The closed monitoring host injects nitrogen according to the O2 concentration in the closed goaf monitored by the multi-parameter sensor device to ensure that the closed goaf is in a low-oxygen environment and the O2 concentration in the closed goaf does not exceed 7%;

[0019] To determine the nitrogen injection flow rate of a closed goaf and its adjacent closed goaf, the nitrogen supply capacity can be calculated according to the nitrogen oxide concentration or the output. The nitrogen supply capacity of the closed goaf depends on the fire prevention and extinguishing requirements and can be calculated as follows:

[0020]

[0021] Where: Q N is the nitrogen supply capacity, m 3 / h; K is the reserve coefficient, which is 1.5; Q0 is the air leakage in the oxidation zone of the closed goaf, m 3 / min; Select according to 1 / 60~1 / 100 of the air volume. The air leakage direction flows from the air inlet tunnel to the return air tunnel, covering the entire area. Therefore, the oxidation zone of the closed goaf is large, and 1 / 60 of the air volume is selected, which is about 22.8m 3 / min; C1 is the average oxygen concentration in the oxidation zone of the closed goaf, which is selected as 15%; C2 is the inerting fire prevention index of the closed goaf, and its value is the critical oxygen concentration of coal spontaneous combustion, which is about 8% in experimental determination; C N is the concentration of injected nitrogen.

[0022] Furthermore, the warning levels are divided according to the temperature and CO concentration settings, and the warning levels are divided into five levels: green, blue, yellow, orange and red; Green warning: CO concentration increases slowly, CO2 concentration increases rapidly, temperature setting 30-70℃, CO concentration setting 1-12ppm; Blue warning: CO concentration increases slowly, CO2 concentration decreases slowly, temperature setting 70-100℃, CO concentration setting 12-80ppm; Yellow warning: CO concentration increases rapidly, CO2 concentration increases slowly, temperature setting 100-120℃, CO concentration setting 80-303ppm; Orange warning: CO and CO2 concentrations increase rapidly, temperature setting 120-190℃, CO concentration setting 303-8825ppm; Red warning: CO and CO2 concentrations increase exponentially, temperature setting above 190℃, CO concentration setting 8825-9830ppm.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention provides a coal mine closed goaf monitoring, early warning and prevention and control system and method, which can solve the problems of large errors, low efficiency and poor timeliness of ground testing of underground sampling, and realizes pre-disaster monitoring, disaster early warning and disaster control and prevention of coal mine closed goaf, thereby facilitating safe production in mines and preventing property losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of the coal mine closed goaf area monitoring, early warning and control system of the present invention;

[0026] Figure 2 It is a control flow chart of the coal mine closed goaf area monitoring, early warning and prevention and control system of the present invention.

[0027] Markings in the figure: 1 is a printer, 2 is a closed monitoring host, 3 is an Internet of Things module, 4 is an underground ring network, 5 is a monitoring substation, 6 is a data conversion and transmission equipment, 7 is a power supply box, 8 is a multi-parameter sensor device, 9 is an explosion-proof electric-controlled ball valve, and 10 is a closed goaf. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Reference Figure 1 and Figure 2 A coal mine closed goaf monitoring, early warning and control system provided by an embodiment of the present invention comprises a multi-parameter sensor device 8, wherein the multi-parameter sensor device 8 is connected to a closed goaf 10, and the multi-parameter sensor device 8 is used to monitor the internal environmental state of the closed goaf 10 in real time; the multi-parameter sensor device 8 is communicatively connected to a monitoring substation 5, and the monitoring substation 5 is communicatively connected to a data conversion and transmission device 6, and the data conversion and transmission device 6 is communicatively connected to a closed monitoring host 2, and the closed monitoring host 2 is used to warn of changes in the internal state of the closed goaf 10; wherein the closed goaf 10, the multi-parameter sensor device 8, the monitoring substation 5, and the data conversion and transmission device 6 are all arranged underground, and the closed monitoring host 2 is arranged on the ground outside the well, and the closed monitoring host 2 and the data conversion and transmission device 6 are communicatively connected via an underground ring network 4. ; The enclosed goaf 10 is also connected to an explosion-proof electric-controlled ball valve 9, and the opening and closing of the explosion-proof electric-controlled ball valve 9 are controlled by the control instructions of the enclosed monitoring host 2 on the ground; when the warning value is exceeded, the enclosed monitoring host 2 issues an opening control instruction to open the explosion-proof electric-controlled ball valve 9, and when the warning is lifted and the data drops to a safe range, the enclosed monitoring host 2 issues a closing control instruction to close the explosion-proof electric-controlled ball valve 9; the explosion-proof electric-controlled ball valve 9 is installed on a branch pipeline of the underground nitrogen injection main pipeline, and the branch pipeline is connected to the measure hole for monitoring the enclosed goaf 10. The RS485 communication protocol is used between the explosion-proof electric-controlled ball valve 9 and the monitoring software of the enclosed monitoring host 2 on the ground to realize data transmission and command communication; the multi-parameter sensing device 8, the monitoring substation 5, the data conversion and transmission equipment 6, and the explosion-proof electric-controlled ball valve 9 are all powered by the power supply box 7.

[0030] The multi-parameter sensing device 8 includes a gas concentration monitoring unit, a temperature and pressure difference monitoring unit, a micro-circulation vacuum pump, an embedded data processing unit, an LCD display unit, and a data communication interface unit. The gas concentration monitoring unit and the temperature and pressure difference monitoring unit are respectively connected to the signal input end of the embedded data processing unit, the micro-circulation vacuum pump and the LCD display unit are respectively connected to the signal output end of the embedded data processing unit, the data communication interface unit is connected to the communication port of the embedded data processing unit, and the multi-parameter sensing device 8 is connected to the monitoring substation 5 through the data communication interface unit; the gas concentration monitoring unit includes an O2 sensor, a CH4 sensor, a CO2 sensor, and a CO sensor; wherein the O2 sensor adopts an electrochemical sensor, and the CH4 sensor, the CO2 sensor, and the CO sensor adopt the NDIR non-dispersive infrared principle for detection. The technology monitors the concentrations of CH4, CO2 and CO. The physical phenomenon that CH4, CO2 and CO absorb mid-infrared light is used to design CH4 sensor, CO2 sensor and CO sensor respectively. The temperature and pressure difference monitoring unit includes a pressure difference sensor and a PT100 temperature sensor. In summary, the multi-parameter sensing device 8 can accurately detect the concentration values ​​of four gases, CO, CO2, CH4 and O2, and the temperature and pressure difference values ​​of the confined space of the coal mine at the same time. The multi-parameter sensing device 8 integrates an embedded system for data acquisition, processing, transmission and storage, and is equipped with an LCD display unit for on-site display of real-time detected gas concentration values, pressure values ​​and temperature values. At the same time, it is used with a matching FYF2 (A) remote control transceiver, and has the functions of zeroing the four gases, CO, O2, CO2 and CH4, zeroing the pressure difference between the closed internal pressure and the closed external pressure, oxygen calibration and CAN address setting.

[0031] The micro-circulating vacuum pump is connected to the enclosed goaf 10 through a bundle pipe. A dust removal and water filter is arranged on the bundle pipe between the micro-circulating vacuum pump and the enclosed goaf 10. The dust removal and water filter is provided with three-stage filtering protection for absorbing impurities such as water vapor and dust in the gas. The gas passes through the dust removal and water filter for dust removal, water removal and drying. The dust removal capacity of the dust removal and water filter is >5μm and the dehumidification rate is 85%. The gas conveying speed of the micro-circulating vacuum pump is not less than 6m / s.

[0032] The multi-parameter sensing device 8 is based on NDIR non-dispersive infrared principle detection technology, and monitors multiple parameters such as O2, CH4, CO2, CO, temperature, pressure difference, etc. inside the closed goaf 10 in real time. It can test and analyze the internal environmental status of the closed goaf 10 from the source, and give early warning of state changes in the closed goaf 10. By injecting nitrogen, it can prevent accidents such as the outburst of toxic and harmful gases in the closed goaf, thereby achieving the purpose of early warning and prevention.

[0033] The monitoring substation 5 adopts an intrinsically safe design and integrates an embedded system for data processing, transmission, storage, and display. The monitoring substation 5 can be equipped with multiple multi-parameter sensor devices 8 for monitoring the closed goaf 10. The monitoring substation 5 processes the received data according to the equipment code, adopts the RS485 communication protocol, and communicates with the closed monitoring host 2 on the ground through the data conversion and transmission equipment 6; the monitoring substation 5 adopts a 24VDC intrinsically safe power supply and is equipped with an LCD screen to display the online and offline, power supply, and operating status of the equipment. When the underground ring network 4 fails, the data can be stored in the monitoring substation 5. After the communication is restored, the handshake protocol is reconnected to automatically upload the monitoring data.

[0034] The enclosed monitoring host 2 is also connected to a printer 1, which is convenient for the staff to print the monitoring data information: historical data, warning records, historical curves, etc. The enclosed monitoring host 2 is connected to the Internet of Things cloud platform through the Internet of Things module 3; the Internet of Things module 3 uploads historical data, warning records, historical curves, etc. to the Internet of Things cloud platform, and the external network can be viewed at any time through the computer and mobile phone APP. Multi-level accounts are created according to different user levels, and different account levels have different access and operation permissions.

[0035] The working principle of the monitoring, early warning and control system for the closed goaf of a coal mine of the present invention is as follows: the micro-circulation vacuum pump inside the multi-parameter sensor device 8 is used to suck the gas in the closed goaf 10 into the device through the bundle tube. After a series of filtration such as dust removal and dehumidification, the gas continuously reaches the gas chamber of the sensor for analysis and is finally emptied. The data detected by the sensor is transmitted to the monitoring substation 5 through the RS485 communication protocol. The monitoring substation 5 uploads the data to the closed monitoring host 2 on the ground through the data conversion and transmission equipment 6. The monitoring software of the closed monitoring host 2 monitors the data in real time and issues an early warning. When the alarm value is exceeded, the monitoring software of the closed monitoring host 2 issues an opening control instruction to open the explosion-proof electric control ball valve 9. When the early warning is lifted and the data drops to a safe range, the monitoring software of the closed monitoring host 2 issues a closing control instruction to close the explosion-proof electric control ball valve 9.

[0036] In addition, a method for monitoring, early warning and controlling a closed goaf area in a coal mine provided in an embodiment of the present invention is implemented by using the above-mentioned monitoring, early warning and controlling system for a closed goaf area in a coal mine, and includes the following steps:

[0037] The warning levels are divided into five levels: green, blue, yellow, orange and red according to the temperature and CO concentration settings. Green warning: CO concentration increases slowly, CO2 concentration increases rapidly, temperature setting 30-70℃, CO concentration setting 1-12ppm; Blue warning: CO concentration increases slowly, CO2 concentration decreases slowly, temperature setting 70-100℃, CO concentration setting 12-80ppm; Yellow warning: CO concentration increases rapidly, CO2 concentration increases slowly, temperature setting 100-120℃, CO concentration setting 80-303ppm; Orange warning: CO and CO2 concentrations increase rapidly, temperature setting 120-190℃, CO concentration setting 303-8825ppm; Red warning: CO and CO2 concentrations increase exponentially, temperature setting above 190℃, CO concentration setting 8825-9830ppm;

[0038] The closed monitoring host 2 issues nitrogen injection and grouting prevention and control instructions according to the warning value, and the explosion-proof electric control ball valve 9 opens 20%, 40%, 60%, 80%, and 100% of the opening corresponding to the five-level warning respectively. When the warning returns to a safe state, the explosion-proof electric control ball valve 9 is automatically closed;

[0039] The closed monitoring host 2 injects nitrogen according to the internal and external pressure difference of the closed goaf 10 monitored by the multi-parameter sensor device 8 to ensure that the closed goaf is at a slightly positive pressure; when the internal-external pressure difference is less than 0Pa, the system issues a nitrogen injection instruction to open the explosion-proof electric-controlled ball valve 9; when the internal-external pressure difference is greater than 2Pa, the system issues a nitrogen injection instruction to close the explosion-proof electric-controlled ball valve 9;

[0040] The closed monitoring host 2 injects nitrogen according to the O2 concentration in the closed goaf 10 monitored by the multi-parameter sensor device 8 to ensure that the closed goaf 10 is in a low-oxygen environment and the O2 concentration in the closed goaf 10 does not exceed 7%;

[0041] The nitrogen injection flow rate of the closed goaf 10 and its adjacent closed goaf 10 can be determined by calculating the nitrogen supply capacity according to the nitrogen oxide concentration or the output. The nitrogen supply capacity of the closed goaf 10 depends on the fire prevention and extinguishing requirements and can be calculated as follows:

[0042]

[0043] Where: Q N is the nitrogen supply capacity, m 3 / h; K is the reserve coefficient, which is 1.5; Q0 is the air leakage in the 10 oxidation zone of the closed goaf, m 3 / min; Select according to 1 / 60~1 / 100 of the air volume, the air leakage direction flows from the air inlet tunnel to the return air tunnel, covering the entire area, so the 10 oxidation zone of the closed goaf is large, and the air volume is selected at 1 / 60, which is about 22.8m 3 / min; C1 is the average oxygen concentration in the 10% oxidation zone of the closed goaf, which is selected as 15%; C2 is the inerting fire prevention index of the closed goaf, which is the critical oxygen concentration of coal spontaneous combustion, which is about 8% in experimental determination; C N is the concentration of injected nitrogen.

[0044] It will be appreciated that, although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A monitoring, early warning and control system for closed goaf areas in coal mines, characterized by: It comprises a multi-parameter sensing device, which is connected to a closed goaf and used for real-time monitoring of the internal environmental status of the closed goaf; the multi-parameter sensing device is communicatively connected to a monitoring substation, which is communicatively connected to a data conversion and transmission device, which is communicatively connected to a closed monitoring host, which is used for early warning of changes in the internal status of the closed goaf; wherein the closed goaf, the multi-parameter sensing device, the monitoring substation and the data conversion and transmission device are all arranged underground, and the closed monitoring host is arranged on the ground outside the well. The enclosed monitoring host is connected to the data conversion and transmission equipment through an underground ring network communication; the enclosed goaf is also connected to an explosion-proof electric-controlled ball valve, and the opening and closing of the explosion-proof electric-controlled ball valve are controlled by the control instructions of the enclosed monitoring host on the ground; when the warning value is exceeded, the enclosed monitoring host sends an opening control instruction to open the explosion-proof electric-controlled ball valve, and when the warning is lifted and the data drops to a safe range, the enclosed monitoring host sends a closing control instruction to close the explosion-proof electric-controlled ball valve; the explosion-proof electric-controlled ball valve is installed on a branch pipeline of the underground nitrogen injection main pipeline, and the branch pipeline is connected to the measure hole for monitoring the enclosed goaf.

2. A coal mine closed goaf monitoring, early warning and control system according to claim 1, characterized in that: The multi-parameter sensing device comprises a gas concentration monitoring unit, a temperature and pressure difference monitoring unit, a micro-circulation air pump, an embedded data processing unit, an LCD display device unit, and a data communication interface unit. The gas concentration monitoring unit and the temperature and pressure difference monitoring unit are respectively connected to the signal input end of the embedded data processing unit, the micro-circulation air pump and the LCD display device unit are respectively connected to the signal output end of the embedded data processing unit, and the data communication interface unit is connected to the communication port of the embedded data processing unit; the multi-parameter sensing device is connected to the monitoring substation through the data communication interface unit.

3. A coal mine closed goaf monitoring, early warning and control system according to claim 2, characterized in that: The gas concentration monitoring unit includes an O2 sensor, a CH4 sensor, a CO2 sensor, and a CO sensor; wherein the O2 sensor adopts an electrochemical sensor, and the CH4 sensor, the CO2 sensor, and the CO sensor all adopt NDIR non-dispersive infrared principle detection technology to monitor the concentrations of CH4, CO2, and CO.

4. A coal mine closed goaf monitoring, early warning and control system according to claim 2, characterized in that: The temperature and pressure difference monitoring unit includes a pressure difference sensor and a PT100 temperature sensor.

5. A coal mine closed goaf monitoring, early warning and control system according to claim 2, characterized in that: The micro-circulation air pump is connected to the closed goaf through a bundle pipe, and a dust removal water filter is arranged on the bundle pipe between the micro-circulation air pump and the closed goaf, and the dust removal water filter is provided with three-level filtering protection.

6. A coal mine closed goaf monitoring, early warning and control system according to claim 1, characterized in that: The monitoring substation adopts 24VDC intrinsically safe power supply and is equipped with an LCD screen to display the online and offline, power supply and operating status of the equipment.

7. A coal mine closed goaf monitoring, early warning and control system according to claim 1, characterized in that: The multi-parameter sensing device, monitoring substation, data conversion and transmission equipment, and explosion-proof electric-controlled ball valve are all powered by a power supply box.

8. A coal mine closed goaf monitoring, early warning and control system according to claim 1, characterized in that: The enclosed monitoring host is also connected to a printer, and the enclosed monitoring host is connected to the Internet of Things cloud platform through the Internet of Things module.

9. A method for monitoring, early warning and control of closed goaf in a coal mine, implemented by using the monitoring, early warning and control system for closed goaf in a coal mine according to any one of claims 1 to 8, characterized in that: The steps include: The closed monitoring host issues nitrogen injection and grouting prevention and control instructions according to the warning value, and the explosion-proof electric control ball valve opens 20%, 40%, 60%, 80%, and 100% of the opening corresponding to the five-level warning respectively. When the warning returns to a safe state, the explosion-proof electric control ball valve is automatically closed; The closed monitoring host injects nitrogen according to the internal and external pressure difference of the closed goaf monitored by the multi-parameter sensor device to ensure that the closed goaf is at a slightly positive pressure; when the internal-external pressure difference is less than 0Pa, the system issues a nitrogen injection command to open the explosion-proof electric-controlled ball valve; when the internal-external pressure difference is greater than 2Pa, the system issues a nitrogen injection command to close the explosion-proof electric-controlled ball valve; The closed monitoring host injects nitrogen according to the O2 concentration in the closed goaf monitored by the multi-parameter sensor device to ensure that the closed goaf is in a low-oxygen environment and the O2 concentration in the closed goaf does not exceed 7%; To determine the nitrogen injection flow rate of a closed goaf and its adjacent closed goaf, the nitrogen supply capacity can be calculated according to the nitrogen oxide concentration or the output. The nitrogen supply capacity of the closed goaf depends on the fire prevention and extinguishing requirements and can be calculated as follows: Where: Q N is the nitrogen supply capacity, m 3 / h; K is the reserve coefficient, which is 1.5; Q0 is the air leakage in the oxidation zone of the closed goaf, m 3 / min; Select 1 / 60 to 1 / 100 of the air volume. The air leakage direction flows from the air inlet tunnel to the return air tunnel, covering the entire area. Therefore, the oxidation zone in the closed goaf is large, and 1 / 60 of the air volume is selected, which is about 22.8m 3 / min; C1 is the average oxygen concentration in the oxidation zone of the closed goaf, which is selected as 15%; C2 is the inerting fire prevention index of the closed goaf, and its value is the critical oxygen concentration of coal spontaneous combustion, which is about 8% in experimental determination; C N is the concentration of injected nitrogen.

10. A method for monitoring, early warning and controlling a closed goaf in a coal mine according to claim 9, characterized in that: The warning levels are divided according to the temperature and CO concentration settings, and the warning levels are divided into five levels: green, blue, yellow, orange and red. Green warning: CO concentration increases slowly, CO2 concentration increases rapidly, temperature setting 30-70℃, CO concentration setting 1-12ppm; Blue warning: CO concentration increases slowly, CO2 concentration decreases slowly, temperature setting 70-100℃, CO concentration setting 12-80ppm; Yellow warning: CO concentration increases rapidly, CO2 concentration increases slowly, temperature setting 100-120℃, CO concentration setting 80-303ppm; Orange warning: CO and CO2 concentrations increase rapidly, temperature setting 120-190℃, CO concentration setting 303-8825ppm; Red warning: CO and CO2 concentrations increase exponentially, temperature setting above 190℃, CO concentration setting 8825-9830ppm.

Images