Fluctuation monitoring device and method for harmful gases in a coal mine

Abstract

The present application relates to the field of coal mine monitoring, and provides a fluctuation monitoring device and method for harmful gas in a coal mine. The fluctuation monitoring device for harmful gas in a coal mine comprises a sampling probe, a sampling pump, a drying and filtering module, a sensing and detecting unit, a data acquisition module and a wireless transmission unit. The fluctuation monitoring device for harmful gas in a coal mine can accurately identify different fluctuation types such as instantaneous fluctuation and periodic fluctuation of gas and carbon monoxide concentration.

Description

Technical Field

[0001] This invention relates to the field of underground coal mine monitoring, and provides a device and method for monitoring fluctuations of harmful gases in underground coal mines. Background Technology

[0002] The statements herein are provided only as background information in connection with this application and do not necessarily constitute prior art.

[0003] Fluctuations in the concentration of hazardous gases (methane and carbon monoxide) in underground coal mines are a key contributing factor to safety accidents such as gas explosions and poisoning. The main components of these gases are methane and carbon monoxide, and their fluctuation characteristics (such as sudden increases in concentration and gradual cumulative fluctuations) directly reflect changes in underground geological structures, the operational status of ventilation systems, and the stability of hazardous gas occurrence. While conventional concentration monitoring devices are now widely used in the field of hazardous gas monitoring in coal mines, significant technical shortcomings remain in terms of the targeted nature, real-time performance, and effectiveness of early warning systems for fluctuation monitoring. Summary of the Invention

[0004] This invention provides a device for monitoring fluctuations of harmful gases in underground coal mines, which addresses the shortcomings of related technologies such as weak targeting, poor real-time performance, and low early warning effectiveness in fluctuation monitoring.

[0005] This invention also provides a method for monitoring fluctuations of harmful gases in underground coal mines.

[0006] A first aspect of the present invention provides a device for monitoring fluctuations of harmful gases in underground coal mines, comprising: Sampling probe, sampling pump, drying and filtering module, sensing and detection unit, data acquisition module and wireless transmission unit; The sampling probe is connected to the sampling pump and is used to extract downhole gas; The output end of the sampling pump is connected to the input end of the drying and filtering module, and the output end of the drying and filtering module is connected to the sensing and detection unit. The sensing and detection unit is communicatively connected to the data acquisition module and is used to detect the concentration of the filtered gas and convert it into a digital signal by the data acquisition module. The wireless transmission unit is connected to the data acquisition module and is used to upload the acquired data to the ground monitoring center; The data acquisition module is equipped with a fluctuation pre-judgment mechanism: after each data acquisition is completed, the previous 10 historical data are called up, the difference between the current concentration and the previous concentration is calculated as the instantaneous fluctuation value, and the standard deviation of the 10 historical data is calculated as the fluctuation stability; when the instantaneous fluctuation value or the standard deviation reaches the set fluctuation attention threshold, it is marked as a fluctuation attention state, and the sampling frequency of the sampling pump is doubled for the next time.

[0007] According to one embodiment of the present invention, the sensing and detection unit includes an infrared methane sensor, an electrochemical carbon monoxide sensor, a temperature sensor, and a humidity sensor; The infrared methane sensor and the electrochemical carbon monoxide sensor are used to simultaneously detect the concentration of harmful gases. The temperature and humidity sensors are used to collect environmental parameters.

[0008] According to one embodiment of the present invention, the data acquisition module is further configured with a frequency recovery mechanism: if the concentration data collected three times consecutively does not reach the fluctuation concern threshold under the fluctuation concern state, the sampling pump is controlled to recover to the default sampling frequency.

[0009] According to one embodiment of the present invention, the wireless transmission unit is configured with a hierarchical transmission mechanism: In a non-fluctuation-sensitive state, the wireless transmission unit packages the data and uploads it to the ground monitoring center at preset time intervals. During the fluctuating attention state, the wireless transmission unit uploads the data collected each time in real time.

[0010] According to one embodiment of the present invention, it further includes a mine explosion-proof power supply module and an audible and visual alarm, wherein the mine explosion-proof power supply module includes power supplies for the sampling pump, the sensing and detection unit, the data acquisition module, the wireless transmission unit, and the audible and visual alarm; When the concentration is detected to reach the first-level fluctuation threshold or the second-level fluctuation threshold, the audible and visual alarm is triggered to issue a multi-level warning.

[0011] A second aspect of the present invention provides a method for monitoring fluctuations of harmful gases in underground coal mines using the apparatus described above, comprising: Periodic sampling steps: Start the sampling pump according to the preset default sampling frequency, extract downhole gas through the sampling probe, and send it to the sensing and detection unit after being filtered by the drying and filtering module. Multi-parameter detection steps: The sensing unit detects the current concentration of the gas and converts the detection data into a digital signal; Fluctuation prediction steps: After each data collection, the historical data from the previous 10 collections is retrieved, the difference between the current concentration and the previous concentration is calculated as the instantaneous fluctuation value, and the standard deviation of the 10 data points is calculated as the fluctuation stability. Dynamic frequency adjustment steps: If the instantaneous fluctuation value or the standard deviation reaches the set fluctuation attention threshold, it is marked as a fluctuation attention state, and the sampling frequency of the next sampling is doubled.

[0012] According to one embodiment of the present invention, the dynamic frequency adjustment step is followed by: If, during the fluctuation monitoring state, three consecutive data collections fail to reach the fluctuation monitoring threshold, the sampling frequency will be restored to the default sampling frequency.

[0013] According to one embodiment of the present invention, a hierarchical transmission step is further included: In non-fluctuation monitoring mode, data containing gas concentration and environmental parameters is packaged and uploaded to the ground monitoring center every 30 seconds via wireless transmission unit; During the fluctuation monitoring state, the collected data for each instance is uploaded in real time via a wireless transmission unit.

[0014] According to one embodiment of the present invention, after receiving the data, the ground monitoring center calculates the gas concentration fluctuation curve per unit time through an algorithm, identifies the fluctuation type of sudden fluctuation, gradual fluctuation or periodic fluctuation, and generates a fluctuation risk assessment by combining historical data and geological condition parameters.

[0015] According to one embodiment of the present invention, a multi-level early warning triggering step is further included: When the concentration change reaches the first-level fluctuation threshold, a first-level fluctuation warning is triggered: the sound and light alarm is controlled to sound intermittently, the yellow warning light flashes, and a warning prompt box pops up in the ground monitoring center. When the concentration change reaches the secondary fluctuation threshold, a secondary fluctuation warning is triggered: the audible and visual alarm will sound continuously, the red warning light will flash, and a voice broadcast will be initiated at the ground monitoring center. At the same time, the fluctuation curve and risk avoidance prompts will be sent to the underground working face.

[0016] The coal mine underground hazardous gas fluctuation monitoring device provided by the first aspect of the present invention features a step-by-step gas path design of sampling, drying and filtering, and detection. This effectively filters out dust and water vapor in the underground gas, avoiding detection distortion caused by sensor moisture and blockage, significantly improving the long-term reliability and accuracy of hazardous gas concentration detection, and adapting to harsh underground working conditions. Employing a dual judgment logic of instantaneous fluctuation value and standard deviation, it can capture both sudden fluctuations in concentration and gradual fluctuations over a long period. Compared to traditional single concentration threshold monitoring, it more accurately reflects changes in the underground gas state, addressing the technical shortcomings of focusing on concentration while neglecting fluctuations. When the gas is stable, it maintains the default sampling frequency, reducing device power consumption and component wear; when abnormal concentration fluctuations occur, it automatically doubles the sampling frequency, encrypting data acquisition and densely tracking fluctuation details to avoid missed detection risks, achieving stable, low-power, and highly encrypted intelligent monitoring. The device integrates sampling, purification, detection, data acquisition, and transmission functions. With compact component connections and no external redundant structures, it can be directly installed in confined underground spaces, meeting the needs of unattended, long-term continuous monitoring in coal mines. The concentration signal is transmitted after digital conversion, which enhances its resistance to downhole electromagnetic interference and makes data transmission more stable. Combined with the wireless transmission unit, it enables seamless data interaction between downhole and the surface, ensuring that monitoring data is uploaded in real time and accurately.

[0017] According to the second aspect of the present invention, the method for monitoring fluctuations of harmful gases in coal mines using the aforementioned device sample at a default frequency, achieving standardized and continuous gas acquisition. Combined with drying and filtration, it effectively eliminates interference from dust and water vapor, providing pure gas samples for accurate detection and adapting to long-term operation under harsh underground conditions. Multi-parameter detection and conversion into digital signals avoids interference from underground electromagnetic fields and dust, resulting in more stable data transmission and more accurate concentration values, providing a reliable data foundation for fluctuation judgment. Employing a dual-dimensional judgment of instantaneous fluctuation values ​​and standard deviation, it can capture both acute fluctuations with sudden increases in concentration and identify discrete, gradual fluctuations within continuous periods, providing a more comprehensive approach compared to single concentration threshold judgment, completely solving the shortcomings of traditional monitoring that emphasizes concentration but neglects fluctuations. When the gas is stable, the default frequency is maintained, reducing device power consumption and component wear; when the concentration is abnormal, the sampling frequency is automatically doubled for encrypted acquisition and intensive tracking, ensuring no fluctuation details are missed, achieving stable, low-power, and highly intensive adaptive monitoring, balancing monitoring accuracy and energy consumption requirements. The method has a closed-loop process that requires no human intervention and can autonomously complete the entire process of sampling, detection, prediction, and frequency adjustment. It meets the needs of unmanned and intelligent monitoring in coal mines and greatly improves the automation and precision of fluctuation monitoring. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart of the method for monitoring fluctuations of harmful gases in underground coal mines provided by the present invention. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] The specific terminology used in this specification is for illustrative purposes only and is not intended to limit the illustrative embodiments. For example, expressions such as "same" and "identical" not only indicate a strictly identical state, but also indicate a state with tolerances or differences in the degree of functionality. For example, expressions such as "towards a certain direction," "along a certain direction," "side by side," "perpendicular," "centered on," "concentric," or "coaxial" indicating relative or absolute arrangement not only strictly indicate such arrangement, but also indicate a state of relative displacement by tolerances or angles or distances with the same degree of functionality.

[0022] In the description of this invention, it should be understood that the terms center, longitudinal, transverse, length, width, thickness, upper, lower, front, back, left, right, vertical, horizontal, top, bottom, inner, outer, clockwise, counterclockwise, axial, radial, circumferential, etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0023] Furthermore, the definition of "first" and "second" features may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "multiple" means two or more. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified. In the description of the embodiments of this application, terms and / or are merely descriptive of the association relationship between related objects, indicating that three relationships may exist. For example, B1 and / or B2 can represent: B1 existing alone, B1 and B2 existing simultaneously, and B2 existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] A first aspect of the present invention provides a device for monitoring fluctuations of harmful gases in underground coal mines, comprising: Sampling probe, sampling pump, drying and filtering module, sensing and detection unit, data acquisition module and wireless transmission unit; The sampling probe is connected to the sampling pump and is used to extract downhole gas; The output of the sampling pump is connected to the input of the drying and filtering module, and the output of the drying and filtering module is connected to the sensing and detection unit. The sensing and detection unit is connected to the data acquisition module to detect the concentration of the filtered gas and convert it into a digital signal by the data acquisition module. The wireless transmission unit is connected to the data acquisition module and is used to upload the acquired data to the ground monitoring center; The data acquisition module is equipped with a fluctuation pre-judgment mechanism: after each data acquisition is completed, the historical data of the previous 10 times is called, the difference between the current concentration and the previous concentration is calculated as the instantaneous fluctuation value, and the standard deviation of the 10 historical data is calculated as the fluctuation stability; when the instantaneous fluctuation value or standard deviation reaches the set fluctuation attention threshold, it is marked as a fluctuation attention state, and the sampling frequency of the sampling pump is doubled for the next sampling.

[0026] The coal mine underground hazardous gas fluctuation monitoring device provided by the first aspect of the present invention features a step-by-step gas path design of sampling, drying and filtering, and detection. This effectively filters out dust and water vapor in the underground gas, avoiding detection distortion caused by sensor moisture and blockage, significantly improving the long-term reliability and accuracy of hazardous gas concentration detection, and adapting to harsh underground working conditions. Employing a dual judgment logic of instantaneous fluctuation value and standard deviation, it can capture both sudden fluctuations in concentration and gradual fluctuations over a long period. Compared to traditional single concentration threshold monitoring, it more accurately reflects changes in the underground gas state, addressing the technical shortcomings of focusing on concentration while neglecting fluctuations. When the gas is stable, it maintains the default sampling frequency, reducing device power consumption and component wear; when abnormal concentration fluctuations occur, it automatically doubles the sampling frequency, encrypting data acquisition and densely tracking fluctuation details to avoid missed detection risks, achieving stable, low-power, and highly encrypted intelligent monitoring. The device integrates sampling, purification, detection, data acquisition, and transmission functions. With compact component connections and no external redundant structures, it can be directly installed in confined underground spaces, meeting the needs of unattended, long-term continuous monitoring in coal mines. The concentration signal is transmitted after digital conversion, which enhances its resistance to downhole electromagnetic interference and makes data transmission more stable. Combined with the wireless transmission unit, it enables seamless data interaction between downhole and the surface, ensuring that monitoring data is uploaded in real time and accurately.

[0027] The fluctuation monitoring device for harmful gases in coal mines provided in the first aspect of the present invention is an integrated underground monitoring device that integrates gas collection, purification, detection, data processing and wireless transmission.

[0028] The sampling probe is directly placed in the area to be tested underground in the coal mine. The outlet of the sampling probe is sealed and connected to the inlet of the sampling pump. The sampling pump drives the sampling probe to complete the extraction of harmful gases underground through negative pressure suction. The outlet of the sampling pump is sealed and connected to the inlet of the drying and filtration module. The extracted underground gas is filtered for dust and dried by the drying and filtration module and then delivered to the back-end sensing and detection unit in a clean and dry state to avoid impurities and water vapor interfering with the detection accuracy.

[0029] The dried and filtered clean gas is passed into the sensing and detection unit to detect the concentration of harmful gases. The sensing and detection unit transmits the concentration analog signal to the data acquisition module, which performs analog-to-digital conversion to convert the analog signal into a digital concentration signal that can be calculated and transmitted.

[0030] The signal output terminal of the data acquisition module is connected to the wireless transmission unit. The converted concentration data and fluctuation status data are transmitted to the ground monitoring center via the wireless transmission unit through the dedicated underground communication network of the coal mine, realizing remote real-time monitoring of underground data.

[0031] The data acquisition module has a built-in storage unit and a computing unit, configured with dedicated fluctuation pre-judgment logic: after each concentration data acquisition is completed, the historical concentration data of the previous 10 consecutive acquisitions is immediately retrieved from the storage unit; the computing unit performs dual calculations: first, it calculates the difference between the current concentration and the previous concentration to obtain the instantaneous fluctuation value, which represents the instantaneous change amplitude of the concentration; second, it calculates the standard deviation of 10 historical data to obtain the fluctuation stability, which represents the long-term dispersion of the concentration fluctuation; the instantaneous fluctuation value and fluctuation stability are compared with the preset fluctuation attention thresholds respectively. If either value reaches the threshold, the data acquisition module immediately marks it as a fluctuation attention state and sends a control command to the sampling pump to trigger the sampling frequency of the next sampling to double.

[0032] According to one embodiment of the present invention, the sensing and detection unit includes an infrared methane sensor, an electrochemical carbon monoxide sensor, a temperature sensor, and a humidity sensor; Infrared methane sensors and electrochemical carbon monoxide sensors are used to simultaneously detect the concentration of harmful gases; Temperature and humidity sensors are used to collect environmental parameters.

[0033] In one embodiment of the present invention, the sensing and detection unit is a multi-parameter integrated detection component, which integrates four types of detection elements: an infrared methane sensor, an electrochemical carbon monoxide sensor, a temperature sensor, and a humidity sensor. The infrared methane sensor has a detection range of 0-100% VOL and a resolution of 0.01% VOL, used for real-time detection of methane gas concentration in the mine. The electrochemical carbon monoxide sensor has a detection range of 0-500 ppm and a resolution of 0.1 ppm, used for simultaneous detection of carbon monoxide gas concentration in the mine. The temperature sensor has a detection range of -20℃ to 60℃, and the humidity sensor has a detection range of 0-95% RH. Both sensors simultaneously collect ambient temperature and humidity parameters in the coal mine, providing environmental compensation for gas concentration detection. The data collected by the four sensors is transmitted uniformly to the data acquisition module for signal conversion.

[0034] The multi-sensor integrated design enables simultaneous detection of methane, carbon monoxide, and environmental parameters such as temperature and humidity, eliminating the need for separate sensor arrangements and improving device integration and detection efficiency. The combination of infrared and electrochemical sensors ensures accurate detection of different gases, including methane and carbon monoxide, and is suitable for monitoring multiple harmful gases in underground coal mines. Real-time acquisition of temperature and humidity parameters allows for environmental compensation of gas concentration detection results, eliminating detection errors caused by changes in underground temperature and humidity, significantly improving the accuracy of fluctuation monitoring, and providing a reliable data foundation for fluctuation prediction.

[0035] According to one embodiment of the present invention, the data acquisition module is further configured with a frequency recovery mechanism: in the fluctuation concern state, if the concentration data collected three times consecutively does not reach the fluctuation concern threshold, the sampling pump is controlled to restore to the default sampling frequency.

[0036] In one embodiment of the present invention, the data acquisition module has built-in frequency recovery logic. The default sampling frequency of the device is 10 seconds / time, and the sampling frequency is doubled to 5 seconds / time under the fluctuation monitoring state. Under the fluctuation monitoring state, the data acquisition module continuously judges the concentration data collected each time. If the instantaneous fluctuation values ​​of methane and carbon monoxide obtained from three consecutive collections are all less than 0.25%VOL and the standard deviation is all less than 1.5ppm, that is, the fluctuation monitoring threshold is not reached for three consecutive times, the data acquisition module immediately sends a control command to the sampling pump to restore the sampling frequency from 5 seconds / time to the initial default of 10 seconds / time, returning to the normal monitoring mode.

[0037] The frequency recovery mechanism enables intelligent bidirectional adjustment of the sampling frequency. It increases the sampling frequency during gas fluctuations to ensure real-time monitoring, and automatically restores the default frequency after the fluctuations subside, avoiding power consumption and device wear caused by continuous high-frequency sampling. The adaptive frequency switching requires no manual intervention, is fully compatible with unattended monitoring scenarios in wells, simplifies the device operation and maintenance process, extends the service life of sampling pumps and sensors, and reduces the long-term operating cost of the device.

[0038] According to one embodiment of the present invention, the wireless transmission unit is configured with a hierarchical transmission mechanism: In non-fluctuation monitoring mode, the wireless transmission unit packages the data and uploads it to the ground monitoring center according to a preset time period; Under fluctuating monitoring conditions, the wireless transmission unit uploads the data collected each time in real time.

[0039] In one embodiment of the present invention, the wireless transmission unit adopts a mining wireless communication module with built-in hierarchical transmission logic. In the non-fluctuation concern state, the wireless transmission unit packages methane concentration, carbon monoxide concentration, temperature and humidity parameters, and device operating status into a set of data frames every 30 seconds and uploads them to the ground monitoring center through the underground monitoring network. In the fluctuation concern state, the hierarchical transmission mechanism automatically switches, the wireless transmission unit terminates data packaging, and immediately uploads the data to the ground monitoring center in real time after each gas concentration acquisition is completed, ensuring that the fluctuation data is transmitted without delay.

[0040] The tiered transmission mechanism balances the low-power requirements of routine monitoring with the real-time requirements of fluctuation monitoring. Under normal conditions, data is uploaded in packets to reduce the frequency of data transmission, lower wireless transmission power consumption, and extend the device's battery life. Under fluctuation conditions, data is uploaded in real time, allowing the ground monitoring center to obtain gas fluctuation data as soon as possible, providing data support for risk warning and emergency response, and solving the technical defects of traditional monitoring devices such as data transmission lag and inability to provide timely feedback on fluctuations.

[0041] According to one embodiment of the present invention, it further includes a mine explosion-proof power supply module and an audible and visual alarm. The mine explosion-proof power supply module includes a sampling pump, a sensing and detection unit, a data acquisition module, a wireless transmission unit, and a power supply for the audible and visual alarm. When the concentration is detected to reach the first-level or second-level fluctuation threshold, the audible and visual alarm is triggered to issue a multi-level warning.

[0042] In one embodiment of the present invention, the monitoring device is further equipped with a mine-use explosion-proof power supply module and an audible and visual alarm. The mine-use explosion-proof power supply module complies with the explosion-proof safety standards for underground coal mines. It draws power from a dedicated underground power supply line to provide a stable DC power supply for the sampling pump, sensor detection unit, data acquisition module, wireless transmission unit, and audible and visual alarm. The power supply voltage is 12V / 24V, and it has overcurrent, overvoltage, and short-circuit protection functions. The audible and visual alarm integrates a yellow warning light, a red warning light, and a buzzer. The preset first-level fluctuation threshold is a methane concentration change ≥0.5%VOL or a carbon monoxide concentration change ≥2.5ppm, and the second-level fluctuation threshold is a methane concentration change ≥1%VOL or a carbon monoxide concentration change ≥5ppm. When the data acquisition module detects the corresponding threshold, it directly triggers the audible and visual alarm to perform the corresponding warning action.

[0043] The explosion-proof power module for mining is suitable for the flammable and explosive high-risk environment of underground coal mines, meets the underground safety power supply standards, eliminates electrical safety hazards, and ensures the long-term stable operation of the device; the multi-level sound and light early warning system enables intuitive early warning on the ground and forms a linkage early warning system with the ground monitoring center. Underground workers can quickly identify the risk level through light and sound, improve the speed of underground emergency response, and maximize the protection of workers' lives.

[0044] See Figure 1 A second aspect of the present invention provides a method for monitoring fluctuations of harmful gases in underground coal mines using the apparatus described above, comprising: Periodic sampling steps: Start the sampling pump according to the preset default sampling frequency, extract downhole gas through the sampling probe, and send it to the sensing and detection unit after being filtered by the drying and filtering module. Multi-parameter detection steps: The sensing unit detects the current concentration of the gas and converts the detection data into a digital signal; Fluctuation prediction steps: After each data collection, the historical data from the previous 10 collections is retrieved, the difference between the current concentration and the previous concentration is calculated as the instantaneous fluctuation value, and the standard deviation of the 10 data points is calculated as the fluctuation stability. Dynamic frequency adjustment steps: If the instantaneous fluctuation value or standard deviation reaches the set fluctuation attention threshold, it is marked as a fluctuation attention state, and the sampling frequency of the next sampling is doubled.

[0045] According to the second aspect of the present invention, the method for monitoring fluctuations of harmful gases in coal mines using the aforementioned device sample at a default frequency, achieving standardized and continuous gas acquisition. Combined with drying and filtration, it effectively eliminates interference from dust and water vapor, providing pure gas samples for accurate detection and adapting to long-term operation under harsh underground conditions. Multi-parameter detection and conversion into digital signals avoids interference from underground electromagnetic fields and dust, resulting in more stable data transmission and more accurate concentration values, providing a reliable data foundation for fluctuation judgment. Employing a dual-dimensional judgment of instantaneous fluctuation values ​​and standard deviation, it can capture both acute fluctuations with sudden increases in concentration and identify discrete, gradual fluctuations within continuous periods, providing a more comprehensive approach compared to single concentration threshold judgment, completely solving the shortcomings of traditional monitoring that emphasizes concentration but neglects fluctuations. When the gas is stable, the default frequency is maintained, reducing device power consumption and component wear; when the concentration is abnormal, the sampling frequency is automatically doubled for encrypted acquisition and intensive tracking, ensuring no fluctuation details are missed, achieving stable, low-power, and highly intensive adaptive monitoring, balancing monitoring accuracy and energy consumption requirements. The method has a closed-loop process that requires no human intervention and can autonomously complete the entire process of sampling, detection, prediction, and frequency adjustment. It meets the needs of unmanned and intelligent monitoring in coal mines and greatly improves the automation and precision of fluctuation monitoring.

[0046] Please continue reading Figure 1 The method for monitoring fluctuations of harmful gases in coal mines provided in the second aspect of the present invention is based on the aforementioned fluctuation monitoring device and is a closed-loop adaptive dynamic monitoring method.

[0047] After the device completes initialization, the sampling pump is started at a set time according to the preset default sampling frequency. The sampling pump uses negative pressure to drive the sampling probe to extract harmful gases from the area to be tested in the coal mine. The extracted gas is first sent to the drying and filtration module. After drying and dust removal purification, a clean gas sample is formed and stably delivered to the sensing and detection unit, providing a gas source free of impurities and interference for concentration detection.

[0048] After the clean gas sample enters the sensing and detection unit, the sensing and detection unit completes the real-time detection of the current concentration of harmful gases and obtains the raw detection signal. The raw signal is synchronously transmitted to the data acquisition module, which performs analog-to-digital conversion to convert the analog detection data into a standardized digital concentration signal for subsequent fluctuation calculation and data transmission.

[0049] After each concentration data acquisition and conversion is completed, the data acquisition module immediately calls up the 10 consecutive historical concentration data stored internally. The computing unit performs two sets of core calculations: first, it calculates the difference between the current concentration and the previous concentration to obtain the instantaneous fluctuation value, which is used to characterize the instantaneous change in concentration; second, it performs statistical calculations on the 10 historical data to obtain the standard deviation, which is used as the fluctuation stability to characterize the degree of dispersion of concentration fluctuation within a continuous period.

[0050] The data acquisition module compares the instantaneous fluctuation value and fluctuation stability with the preset fluctuation attention threshold. If the instantaneous fluctuation value or fluctuation stability (standard deviation) meets the standard, the monitoring status is immediately marked as fluctuation attention status. At the same time, a control command is sent to the sampling pump to trigger the sampling frequency of the next sampling to double the default frequency, so as to track gas concentration changes with a higher sampling density.

[0051] According to one embodiment of the present invention, the dynamic frequency adjustment step is followed by: If the fluctuation monitoring threshold is not reached in three consecutive data collections under the fluctuation monitoring state, the sampling frequency will be restored to the default frequency.

[0052] In one embodiment of the present invention, after the dynamic frequency adjustment step is executed, the device enters the fluctuation monitoring state and the sampling frequency is increased to 5 seconds / time; the data acquisition module continuously tracks the subsequent acquired data, and uses the instantaneous fluctuation value <0.25%VOL and standard deviation <1.5ppm as the judgment standard. If the methane and carbon monoxide concentration data collected three times in a row meet the standard, that is, the gas fluctuation has subsided, the frequency recovery command is automatically triggered to restore the sampling frequency of the sampling pump from 5 seconds / time to the initial default of 10 seconds / time, and the device returns to the normal periodic sampling mode.

[0053] This step enables closed-loop intelligent adjustment of the sampling frequency, with increased sampling frequency during fluctuations and automatic frequency reduction after fluctuations subside. While ensuring the accuracy of fluctuation monitoring, it effectively reduces the energy consumption and mechanical wear of the device. The fully automatic closed-loop control requires no manual operation, fully adapting to the unmanned and intelligent monitoring needs of underground coal mines, and improving the automation level and stability of the device operation.

[0054] According to one embodiment of the present invention, a hierarchical transmission step is further included: In non-fluctuation monitoring mode, data containing gas concentration and environmental parameters is packaged and uploaded to the ground monitoring center every 30 seconds via wireless transmission unit; Under fluctuating monitoring conditions, each collection of data is uploaded in real time via a wireless transmission unit.

[0055] In one embodiment of the present invention, the hierarchical transmission step is the core process of data uploading. In the non-fluctuation-concern state, the data acquisition module temporarily stores data such as methane concentration, carbon monoxide concentration, temperature, humidity, and device status in the buffer area. After accumulating data for 30 seconds, a data packet is generated and uploaded to the ground monitoring center by the wireless transmission unit. In the fluctuation-concern state, the data packetization logic is paused. After each concentration acquisition by the sensing unit is completed, the data acquisition module immediately transmits the single data packet to the wireless transmission unit, which then uploads it to the ground monitoring center in real time, without data delay or buffering.

[0056] The tiered transmission process enables adaptive switching of data transmission strategies. Under normal conditions, packetized uploading reduces wireless transmission traffic and power consumption, adapting to the low-power operation requirements of downhole systems. Under fluctuating conditions, real-time direct transmission ensures that the ground monitoring center obtains gas fluctuation data with zero delay, saving time for risk assessment and emergency response, and completely solving the industry pain points of traditional monitoring devices such as data transmission lag and inability to track real-time fluctuations.

[0057] According to one embodiment of the present invention, after receiving data, the ground monitoring center calculates the gas concentration fluctuation curve per unit time through an algorithm, identifies the fluctuation type of sudden fluctuation, gradual fluctuation or periodic fluctuation, and generates a fluctuation risk assessment by combining historical data and geological condition parameters.

[0058] In one embodiment of the present invention, the ground monitoring center is equipped with a dedicated fluctuation analysis algorithm. After the receiving device uploads data, it plots the concentration fluctuation curves of methane and carbon monoxide in three time units: 1 minute, 5 minutes, and 10 minutes. By analyzing the curve slope, fluctuation period, and fluctuation amplitude characteristics, the fluctuation type is identified: a sudden increase in concentration in a short period of time is a sudden fluctuation; a slow and continuous increase in concentration is a gradual fluctuation; and regular fluctuations in concentration are periodic fluctuations. Combining the historical gas data of the monitoring point, the geological conditions of the tunnel, and ventilation parameters, a three-level fluctuation risk assessment of low risk, medium risk, and high risk is generated and displayed visually on the monitoring platform.

[0059] Ground-based intelligent analysis enables precise classification and risk quantification of gas fluctuations, distinguishing different fluctuation types from different underground risks (such as sudden fluctuations corresponding to gas outburst risks), providing accurate decision-making basis for coal mine safety management; combined with risk assessment based on historical data and geological parameters, it eliminates the possibility of misjudgment based on single concentration data, significantly improving the targeting and effectiveness of fluctuation monitoring, and assisting in the refined management of harmful gases underground.

[0060] According to one embodiment of the present invention, a multi-level early warning triggering step is further included: When the concentration change reaches the first-level fluctuation threshold, a first-level fluctuation warning is triggered: the sound and light alarm is controlled to sound intermittently, the yellow warning light flashes, and a warning prompt box pops up in the ground monitoring center. When the concentration change reaches the secondary fluctuation threshold, a secondary fluctuation warning is triggered: the audible and visual alarm will sound continuously, the red warning light will flash, and a voice broadcast will be initiated at the ground monitoring center. At the same time, the fluctuation curve and risk avoidance prompts will be sent to the underground working face.

[0061] In one embodiment of the present invention, the multi-level early warning triggering step presets two levels of fluctuation thresholds: the first-level fluctuation threshold is a change in methane concentration ≥ 0.5% VOL or a change in carbon monoxide concentration ≥ 2.5 ppm, and the second-level fluctuation threshold is a change in methane concentration ≥ 1% VOL or a change in carbon monoxide concentration ≥ 5 ppm; when the data acquisition module detects that the concentration change meets the standard, it immediately triggers the corresponding early warning: during the first-level early warning, the audible and visual alarm buzzer sounds intermittently, the yellow warning light flashes, and the ground monitoring center displays a pop-up notification; during the second-level early warning, the audible and visual alarm buzzer sounds continuously, the red warning light flashes, the ground monitoring center starts a voice broadcast, and at the same time sends the fluctuation curve and avoidance command to the underground working face substation.

[0062] The two-tiered early warning mechanism distinguishes risk levels, enabling tiered early warning and tiered response. Level 1 early warning prompts attention, while Level 2 early warning prompts emergency evacuation. The early warning instructions are clear and unambiguous. The underground audible and visual early warning system, together with the ground center's early warning and the working face's end-to-end prompts, forms a three-dimensional linkage early warning system, comprehensively covering underground workers and ground management personnel. This significantly improves the early warning coverage and response efficiency, effectively reducing the risk of safety accidents caused by fluctuations in harmful gases in coal mines.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for monitoring fluctuations of harmful gases in underground coal mines, characterized in that, include: Sampling probe, sampling pump, drying and filtering module, sensing and detection unit, data acquisition module and wireless transmission unit; The sampling probe is connected to the sampling pump and is used to extract downhole gas; The output end of the sampling pump is connected to the input end of the drying and filtering module, and the output end of the drying and filtering module is connected to the sensing and detection unit. The sensing and detection unit is communicatively connected to the data acquisition module and is used to detect the concentration of the filtered gas and convert it into a digital signal by the data acquisition module. The wireless transmission unit is connected to the data acquisition module and is used to upload the acquired data to the ground monitoring center; The data acquisition module is equipped with a fluctuation pre-judgment mechanism: after each data acquisition is completed, the previous 10 historical data are called up, the difference between the current concentration and the previous concentration is calculated as the instantaneous fluctuation value, and the standard deviation of the 10 historical data is calculated as the fluctuation stability; when the instantaneous fluctuation value or the standard deviation reaches the set fluctuation attention threshold, it is marked as a fluctuation attention state, and the sampling frequency of the sampling pump is doubled for the next time.

2. The coal mine underground harmful gas fluctuation monitoring device according to claim 1, characterized in that, The sensing and detection unit includes an infrared methane sensor, an electrochemical carbon monoxide sensor, a temperature sensor, and a humidity sensor. The infrared methane sensor and the electrochemical carbon monoxide sensor are used to simultaneously detect the concentration of harmful gases. The temperature and humidity sensors are used to collect environmental parameters.

3. The coal mine underground harmful gas fluctuation monitoring device according to claim 1, characterized in that, The data acquisition module is also equipped with a frequency recovery mechanism: under the fluctuation concern state, if the concentration data collected three times consecutively does not reach the fluctuation concern threshold, the sampling pump is controlled to restore to the default sampling frequency.

4. The coal mine underground harmful gas fluctuation monitoring device according to claim 1, characterized in that, The wireless transmission unit is equipped with a hierarchical transmission mechanism: In a non-fluctuation-sensitive state, the wireless transmission unit packages the data and uploads it to the ground monitoring center at preset time intervals. During the fluctuating attention state, the wireless transmission unit uploads the data collected each time in real time.

5. The coal mine underground harmful gas fluctuation monitoring device according to claim 1, characterized in that, It also includes a mine explosion-proof power module and an audible and visual alarm. The mine explosion-proof power module includes power supplies for the sampling pump, sensing and detection unit, data acquisition module, wireless transmission unit, and audible and visual alarm. When the concentration is detected to reach the first-level fluctuation threshold or the second-level fluctuation threshold, the audible and visual alarm is triggered to issue a multi-level warning.

6. A method for monitoring fluctuations of harmful gases in underground coal mines using the apparatus described in any one of claims 1 to 5, characterized in that, include: Periodic sampling steps: Start the sampling pump according to the preset default sampling frequency, extract downhole gas through the sampling probe, and send it to the sensing and detection unit after being filtered by the drying and filtering module. Multi-parameter detection steps: The sensing unit detects the current concentration of the gas and converts the detection data into a digital signal; Fluctuation prediction steps: After each data collection, the historical data from the previous 10 collections is retrieved, the difference between the current concentration and the previous concentration is calculated as the instantaneous fluctuation value, and the standard deviation of the 10 data points is calculated as the fluctuation stability. Dynamic frequency adjustment steps: If the instantaneous fluctuation value or the standard deviation reaches the set fluctuation attention threshold, it is marked as a fluctuation attention state, and the sampling frequency of the next sampling is doubled.

7. The method for monitoring fluctuations of harmful gases in underground coal mines according to claim 6, characterized in that, Following the dynamic frequency adjustment step, the following is also included: If, during the fluctuation monitoring state, three consecutive data collections fail to reach the fluctuation monitoring threshold, the sampling frequency will be restored to the default sampling frequency.

8. The method for monitoring fluctuations of harmful gases in underground coal mines according to claim 6, characterized in that, It also includes a hierarchical transmission step: In non-fluctuation monitoring mode, data containing gas concentration and environmental parameters is packaged and uploaded to the ground monitoring center every 30 seconds via wireless transmission unit; During the fluctuation monitoring state, the collected data for each instance is uploaded in real time via a wireless transmission unit.

9. The method for monitoring fluctuations of harmful gases in underground coal mines according to claim 8, characterized in that, After receiving the data, the ground monitoring center uses an algorithm to calculate the gas concentration fluctuation curve per unit time, identify the fluctuation type of sudden fluctuation, gradual fluctuation or periodic fluctuation, and generate a fluctuation risk assessment by combining historical data and geological condition parameters.

10. The method for monitoring fluctuations of harmful gases in underground coal mines according to claim 6, characterized in that, It also includes multi-level warning triggering steps: When the concentration change reaches the first-level fluctuation threshold, a first-level fluctuation warning is triggered: the sound and light alarm is controlled to sound intermittently, the yellow warning light flashes, and a warning prompt box pops up in the ground monitoring center. When the concentration change reaches the secondary fluctuation threshold, a secondary fluctuation warning is triggered: the audible and visual alarm will sound continuously, the red warning light will flash, and a voice broadcast will be initiated at the ground monitoring center. At the same time, the fluctuation curve and risk avoidance prompts will be sent to the underground working face.

Images