Mine circulating air monitoring and identifying method and system based on differential pressure analysis
By installing pressure and gas sensors in the mine's local ventilation system, and combining differential pressure and gas concentration analysis, the problem of inaccurate monitoring of mine circulating air was solved, enabling timely and accurate identification of circulating air and ensuring safe production in the mine.
Patent Information
- Application Number
- CN202511353435.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-22
- Publication Date
- 2025-11-14
AI Technical Summary
Existing mine circulating ventilation monitoring methods are inaccurate and unreliable, failing to effectively identify the risk of gas accumulation caused by circulating ventilation, making it difficult to detect and address safety hazards in a timely manner.
By installing pressure sensors and gas sensors on the inlet side of the local ventilator and at the intersection of the return airflow and the inlet airflow, combined with differential pressure dynamic analysis and gas concentration trend analysis, the system can monitor changes in differential pressure and abnormal gas concentration, thereby achieving accurate identification of the circulating air.
It enables timely and accurate identification of circulating air, avoids disasters such as gas accumulation, provides a powerful safety management tool, and ensures safe production in the mine.
Smart Images
Figure CN120946404A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of mine ventilation safety technology, and relates to a method and system for monitoring and identifying mine circulating air based on differential pressure analysis. Background Technology
[0002] Mine ventilation systems are critical infrastructure for ensuring safe production in mines. Their main functions are to provide sufficient fresh air for underground workers, dilute and remove toxic and harmful gases such as methane and dust generated during operations, and regulate the temperature and humidity of the underground working environment. During mine development and tunneling, it is usually necessary to use local ventilation fans and ducts to direct fresh air to the working face in addition to the main ventilation roadway to meet the ventilation needs of local areas.
[0003] However, this localized ventilation method is prone to recirculating air problems under certain conditions. Recirculating air refers to a phenomenon where a portion of the exhaust air (i.e., the polluted airflow discharged from the tunneling face) does not enter the return airway through the normal path, but is instead repeatedly drawn in by the local ventilation fan, mixed with fresh air, and then sent back to the tunneling face. The causes of recirculating air are varied, usually related to factors such as improper installation of the local ventilation fan, excessive suction capacity, insufficient air supply in the intake airway, or unreasonable ventilation system design. The direct hazard of recirculating air is that toxic and harmful gases such as methane generated at the tunneling face cannot be effectively diluted and discharged, causing localized methane accumulation. When the concentration reaches the explosive limit, it can easily trigger major accidents such as methane explosions, posing a huge threat to the lives of underground personnel and mine property.
[0004] Currently, the industry has limited methods for monitoring circulating air. One common approach is to install gas sensors near the inlet of local ventilation fans to determine the presence of circulating air by monitoring gas concentration. However, practice has shown that due to the extremely turbulent airflow at the fan inlet, the sensors struggle to obtain stable and representative gas concentration readings, resulting in low accuracy and reliability of this method, which cannot meet the precise monitoring needs of mine safety production. Therefore, a more scientific and accurate method for monitoring and identifying circulating air in mines is urgently needed. Summary of the Invention
[0005] The present invention aims to solve the technical problems of inaccuracy and poor reliability of existing circulating air monitoring methods, and provides a mine circulating air monitoring and identification method and system based on differential pressure analysis.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] A method for monitoring and identifying mine circulating air based on differential pressure analysis includes the following steps: acquiring first pressure data at a first monitoring point located on the air inlet side of a local ventilation fan, and second pressure data at a second monitoring point located at the intersection of the return air flow and the air inlet flow; calculating and monitoring the temporal change of the pressure difference between the two based on the first pressure data and the second pressure data; acquiring gas concentration data; and determining that a circulating air failure has occurred when the pressure difference decreases and reverses, and the gas concentration data shows an abnormal upward trend.
[0008] A mine circulating air monitoring and identification system based on differential pressure analysis includes: a first monitoring module for acquiring first pressure data at a first monitoring point located on the air inlet side of a local ventilation fan; a second monitoring module for acquiring second pressure data at a second monitoring point located at the intersection of the return airflow and the inlet airflow; a gas monitoring module for acquiring gas concentration data; and a processing module connected to each module. The processing module calculates and monitors the temporal change of the pressure difference between the first and second pressure data; and determines a circulating air fault has occurred when it detects a decrease and reversal in the pressure difference and an abnormal upward trend in the gas concentration data.
[0009] The beneficial effects of this invention are as follows: This monitoring and identification method and system innovatively combines dynamic analysis of airflow pressure difference with gas concentration trend analysis. By monitoring the precursors (pressure difference changes and reversals) and consequences (abnormal rise in gas concentration) of circulating air, it achieves timely and accurate identification of major safety hazards related to circulating air in tunneling faces. This invention can effectively avoid disasters such as gas accumulation caused by circulating air, providing strong technical support for monitoring and managing this major safety hazard in coal mines, and also providing scientific management tools and advanced technical means for mine ventilation gas safety management and safe production.
[0010] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description
[0011] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:
[0012] Figure 1 The flowchart of the monitoring and identification method provided by the present invention is shown below.
[0013] Figure 2 This is a schematic diagram of the sensor arrangement in one embodiment of the present invention;
[0014] Figure 3 This is a schematic diagram of the ventilation network topology for the circulating air scenario described in this invention. Detailed Implementation
[0015] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0016] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.
[0017] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0018] Reference Figure 1 This invention provides a method for monitoring and identifying mine circulating air based on differential pressure analysis, the process of which mainly includes the following steps:
[0019] Step S1: Determine the method and location for monitoring differential pressure of local ventilation fans.
[0020] This step aims to determine the physical location for monitoring key characteristic parameters of the circulating air. For example... Figure 2 As shown, two key monitoring points were selected. The first monitoring point was located in the intake roadway on the intake side of the local ventilation fan. The second monitoring point was located at the intersection of the return airflow and the total intake airflow in the tunneling roadway. These two points represent the start and end points of the airflow short-circuit path when circulating air occurs, respectively, and the pressure difference between them is the direct physical basis for determining whether circulating air has occurred.
[0021] To achieve accurate monitoring, a first absolute pressure sensor (in Pa) and a first wind speed sensor (in m / s) are installed at the first monitoring point; a second absolute pressure sensor (in Pa) and a second wind speed sensor (in m / s) are installed at the second monitoring point. In addition, a methane sensor (i.e., a gas monitoring module) is installed at the return airflow point of the tunneling roadway to monitor the concentration of methane emitted from the tunneling face in real time.
[0022] Step S2: Pressure monitoring data acquisition and filtering.
[0023] By deploying sensors at the locations described in step S1, the system collects the absolute pressure and wind speed values at the first and second monitoring points, as well as the gas concentration value in the return airflow, in real time and synchronously. To improve the accuracy of the data, the collected raw data can first undergo data filtering processing, such as using mean filtering, median filtering, and other algorithms to filter out noise data caused by electrical interference or instantaneous airflow pulsations.
[0024] Step S3: Time series data analysis to calculate pressure difference changes.
[0025] This step is the core of identifying potential hazards in the circulating ventilation system. The processing module (such as an industrial computer or dedicated controller integrated into the mine monitoring system) calculates and analyzes the collected data.
[0026] First, calculate the total pressure at both monitoring points. The total pressure P at each monitoring point... 全压 It is a total energy representation for judging the driving capacity of airflow, and its calculation formula is:
[0027] P 全压 =P 绝对压力 +P 速压 +P 位压
[0028] Among them, P 绝对压力 The velocity pressure P is directly measured by an absolute pressure sensor. 速压 It is the kinetic energy of the airflow due to its velocity, calculated based on the wind speed v measured by the wind speed sensor. The calculation formula is as follows:
[0029] P 速压 =ρv 2
[0030] In the formula, ρ is the air density and v is the wind speed monitored by the wind speed sensor.
[0031] Potential pressure P 位压 This is the potential energy difference caused by the different altitudes of the monitoring points, and its calculation formula is:
[0032]
[0033] In the formula, ρ1 and h1 are the air density and elevation of the first monitoring point, respectively, ρ2 and h2 are the air density and elevation of the second monitoring point, and g is the gravitational acceleration (usually taken as 9.81 m / s²).
[0034] Then, calculate the pressure difference P between the two monitoring points. 差 :P 差 =P 1全压 -P 2全压
[0035] Among them, P 1全压 P is the total pressure at the first monitoring point. 2全压 This is the total pressure at the second monitoring point.
[0036] The system continuously calculates the pressure difference at fixed time intervals (e.g., per second or per minute), forming a time series of the pressure difference.
[0037] Step S4: Determine if there is a problem with the circulating air.
[0038] This step makes a comprehensive judgment based on the pressure difference trend and the gas concentration trend.
[0039] Reference Figure 3 The ventilation network topology diagram shows that, under normal circumstances, fresh air flows along directions e1 and e2. Local ventilation fans draw air from near point P1 and deliver it to the tunnel face via the virtual duct e3. Exhaust air is discharged along directions e4 and e5. At this time, the total pressure at the first monitoring point (near P1) is higher than the total pressure at the second monitoring point (near P2), i.e., P... 差 It is a stable positive value.
[0040] When a potential recirculation problem occurs, such as insufficient air supply in the intake airway, the strong negative pressure of the local ventilation fan can cause some of the exhaust air to backflow from point P2 to point P1, resulting in reverse airflow in branch e2. This process is reflected in the monitoring data as: the total pressure difference P between the two monitoring points. 差 It will gradually decrease. When a recirculation failure occurs, the total pressure at point P2 will exceed the total pressure at point P1, resulting in a pressure difference P. 差 When the value turns negative, a "pressure reversal" occurs. The system uses this "pressure reversal" phenomenon as a strong early warning signal that circulating air may be present.
[0041] Pressure reversal alone is insufficient to definitively confirm a fault; further confirmation requires integration with gas concentration data. When the processing module detects pressure reversal, it immediately focuses on analyzing the time-series trend of the concentration data uploaded by the gas monitoring module. If the gas concentration data shows a continuous and abnormal upward trend, it confirms that contaminated exhaust air has been re-mixed into the intake airflow, causing gas to circulate and accumulate at the tunneling face.
[0042] In this embodiment, the processing module can use an anomaly detection algorithm (Long Short-Term Memory-Anomaly Detection, LSTM-AD) to analyze the gas concentration time series. LSTM-AD is a deep learning model that excels at processing time series data. It can learn the fluctuation pattern of gas concentration under normal ventilation conditions and accurately identify abnormal upward trends that exceed the normal range caused by circulating air.
[0043] Ultimately, when both conditions of "pressure reversal" and "abnormal rise in gas concentration" are met simultaneously, the system determines that a circulating air failure has occurred and immediately triggers an alarm to notify management personnel to take measures.
[0044] This invention also provides a monitoring and identification system for implementing the above method. The system includes hardware and software components. The hardware components consist of a first monitoring module (a first absolute pressure sensor and a first wind speed sensor), a second monitoring module (a second absolute pressure sensor and a second wind speed sensor), and a gas monitoring module (a methane sensor) deployed underground. The software component is embedded in a processing module that receives data from each monitoring module and executes the calculation, analysis, and judgment logic in steps S3 and S4 above, ultimately outputting the identification result.
[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for monitoring and identifying mine circulating air based on differential pressure analysis, characterized in that: Includes the following steps: Acquire first pressure data at a first monitoring point located on the air inlet side of the local ventilation fan, and second pressure data at a second monitoring point located at the intersection of the return air flow and the air inlet flow; Based on the first pressure data and the second pressure data, calculate and monitor the temporal change of the pressure difference between them; Obtain gas concentration data; When the pressure difference is detected to decrease and then reverse, and the gas concentration data shows an abnormal upward trend, a circulating air failure is determined to have occurred.
2. The mine circulating air monitoring and identification method based on differential pressure analysis according to claim 1, characterized in that: The steps for obtaining the first pressure data and the second pressure data include: A first absolute pressure sensor and a first wind speed sensor are installed at the first monitoring point; A second absolute pressure sensor and a second wind speed sensor are installed at the second monitoring point; The first pressure data and the second pressure data are obtained in real time by using the first and second absolute pressure sensors and the first and second wind speed sensors.
3. The mine circulating air monitoring and identification method based on differential pressure analysis according to claim 2, characterized in that: The first pressure data is the first total pressure at the first monitoring point, and the second pressure data is the second total pressure at the second monitoring point; the pressure difference is the value obtained by subtracting the second total pressure from the first total pressure.
4. The mine circulating air monitoring and identification method based on differential pressure analysis according to claim 3, characterized in that: The first total pressure and the second total pressure are calculated by the following formula: P 全压 =P 绝对压力 +P 速压 +P 位压 Among them, P 全压 P is the total pressure at the monitoring point. 绝对压力 P is the absolute pressure monitored by the absolute pressure sensor. 速压 For rapid pressure, P 位压 This refers to potential pressure.
5. The mine circulating air monitoring and identification method based on differential pressure analysis according to claim 4, characterized in that: The velocity pressure is calculated by the following formula: P 速压 =ρv 2 Where ρ is the air density and v is the wind speed monitored by the wind speed sensor.
6. The mine circulating air monitoring and identification method based on differential pressure analysis according to claim 4, characterized in that: The potential pressure is calculated by the following formula: Wherein, ρ1 is the air density at the first monitoring point, ρ2 is the air density at the second monitoring point, h1 is the elevation of the first monitoring point, h2 is the elevation of the second monitoring point, and g is the gravitational acceleration.
7. The mine circulating air monitoring and identification method based on differential pressure analysis according to claim 1, characterized in that: The pressure difference decreases and reverses when the pressure at the second monitoring point is greater than the pressure at the first monitoring point.
8. The mine circulating air monitoring and identification method based on differential pressure analysis according to claim 1, characterized in that: The abnormal upward trend in the gas concentration data was determined by analysis using an anomaly detection algorithm (Long Short-Term Memory-Anomaly Detection, LSTM-AD).
9. A mine circulating air monitoring and identification system based on differential pressure analysis, characterized in that: include: The first monitoring module is used to acquire the first pressure data at the first monitoring point located on the air inlet side of the local ventilation fan; The second monitoring module is used to acquire the second pressure data at the second monitoring point located at the intersection of the return air flow and the inlet air flow. The gas monitoring module is used to acquire gas concentration data; The processing module, connected to the first monitoring module, the second monitoring module, and the gas monitoring module, is used for: Based on the first pressure data and the second pressure data, calculate and monitor the temporal change of the pressure difference between them; When the pressure difference is detected to decrease and then reverse, and the gas concentration data shows an abnormal upward trend, a circulating air failure is determined to have occurred.
10. The mine circulating air monitoring and identification system based on differential pressure analysis according to claim 9, characterized in that: The first monitoring module includes a first absolute pressure sensor and a first wind speed sensor; the second monitoring module includes a second absolute pressure sensor and a second wind speed sensor.
11. The mine circulating air monitoring and identification system based on differential pressure analysis according to claim 10, characterized in that: The processing module is specifically used for: The first total pressure calculated by the first absolute pressure sensor and the first wind speed sensor is used as the first pressure data. The second total pressure calculated by the second absolute pressure sensor and the second wind speed sensor is used as the second pressure data. The total pressure is obtained by adding the absolute pressure, velocity pressure and potential pressure at the monitoring point.
12. The mine circulating air monitoring and identification system based on differential pressure analysis according to claim 11, characterized in that: The processing module calculates the velocity pressure and potential pressure using the following formula: P 速压 =ρv 2 Among them, P 速压 For rapid pressure, P 位压 ρ is the potential pressure, v is the air density, v is the wind speed monitored by the wind speed sensor, ρ1 is the air density at the first monitoring point, ρ2 is the air density at the second monitoring point, h1 is the elevation of the first monitoring point, h2 is the elevation of the second monitoring point, and g is the gravitational acceleration.
13. The mine circulating air monitoring and identification system based on differential pressure analysis according to claim 9, characterized in that: The processing module uses the LSTM-AD anomaly detection algorithm to analyze the gas concentration data to determine whether it shows an abnormal upward trend.