Coal mine underground electric pulse induced coal seam safety early warning device

Abstract

The application provides a coal mine underground electric pulse induced cracking coal seam safety warning device, which comprises a hole sealer, a capsule section is arranged in the middle of the hole sealer, an installation ring is fixedly connected to the lower bottom of the capsule section, a warning device body is fixedly connected to the outer end of the installation ring, and a fixing ring is fixedly connected to the middle and upper end of the capsule section. The safety warning module and the hole sealer are integrated in an integrated structure, are directly installed at the outer end of the capsule and enter the drilling cracking core area together, break through the traditional mode of independent installation of monitoring equipment, realize the source of safety monitoring, enable the sensor to be best coupled with the coal body, directly obtain the most original and most advanced physical information in the cracking process, provide a solid foundation for advanced warning, and realize the synchronous completion of hole sealing operation and monitoring system deployment, simplify the underground operation process and improve the engineering practicability and reliability of the system.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, specifically to a safety early warning device for coal seam fracturing caused by electric pulse in underground coal mines. Background Technology

[0002] In coal mining, high-gas, low-permeability coal seams are prone to gas outbursts and rock bursts due to gas accumulation and stress concentration, hindering safe mining. Electrical pulse fracturing technology uses high-frequency, high-voltage electrical pulses to create micro-fractures in the coal seam, achieving pressure relief and increased permeability. This can improve gas extraction efficiency and reduce stress disaster risks, making it a key auxiliary technology for high-risk coal seam mining. However, the high-energy impact during fracturing can cause dynamic coal seam fracture, leading to stress field reconstruction and a sudden increase in gas desorption. Furthermore, underground electromagnetic interference and dust can easily mask risk signals. Without real-time and accurate early warning, safety accidents can easily occur. Therefore, safety early warning during fracturing operations is a core requirement for ensuring mining safety.

[0003] Current safety monitoring technologies related to electrically pulsed fracturing of coal seams in underground coal mines still have several specific shortcomings, making it difficult to meet the safety requirements of actual operations. First, monitoring parameters are limited, leading to incomplete risk identification: Existing technologies mostly focus on monitoring a single parameter, such as monitoring gas concentration in the fracturing area solely through gas sensors, or relying solely on temperature sensors to capture local coal temperature changes, neglecting key precursor signals during coal fracturing—such as vibrations (acoustic emission) generated by dynamic coal fracturing and electromagnetic radiation accompanying stress release. In actual operations, coal instability and abnormal gas outbursts are often the result of multiple factors working together; relying on a single parameter easily leads to "missed detections" or "false detections": when the coal seam has already fractured violently but the gas has not yet spread to an excessive concentration, existing devices cannot provide early warning, resulting in delayed warnings; while when local gas levels fluctuate briefly due to airflow disturbances underground, unnecessary false alarms may occur, interfering with normal operational procedures. Second, there is a lack of coordinated control capabilities, resulting in untimely risk handling: most existing early warning devices only have an "alarm prompt" function and have not formed a coordinated control mechanism with the electrically pulsed fracturing equipment. Even if risk signals such as excessive gas levels or abnormal temperatures are detected, it still requires manual judgment by operators to manually cut off the power to fracturing equipment. However, the complex underground working environment and the time lag in personnel reaction can easily lead to an escalation of risks due to delayed response, making it impossible to achieve proactive protection of "early warning as intervention". Furthermore, insufficient installation coupling accuracy leads to distorted monitoring signals: Existing devices often adopt a "separate design of the sealing device and the early warning module". During installation, the sealing device, early warning sensor and other components must be inserted into the borehole one by one and fixed separately. This not only increases the number of underground operation steps and reduces work efficiency, but also easily leads to poor coupling between the early warning module and the coal wall due to installation deviations. For example, the sensor probe may not be able to fit tightly against the coal wall, resulting in attenuation of coal vibration signal transmission and lag in temperature sensing, directly affecting the accuracy of monitoring data. Finally, the equipment suffers from poor environmental adaptability and insufficient long-term reliability: the existing early warning device's outer shell is not optimized for the harsh downhole environment, and the lack of a wear-resistant layer makes the shell susceptible to dust erosion and mechanical impact wear; the inner lining shielding layer is missing or has insufficient performance, making it susceptible to strong electromagnetic interference generated by the electric pulse fracturing equipment, resulting in erratic monitoring signals; at the same time, the internal components are mostly fixed by simple mechanical means without being potted with thermally conductive insulating glue, which not only fails to effectively enhance heat dissipation (leading to component failure due to high temperature), but also makes it difficult to withstand the vibration and impact generated by fracturing operations, easily leading to component loosening, poor contact and other faults, further reducing the long-term operational reliability of the early warning device. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a safety early warning device for coal seams fractured by electrical pulses in underground coal mines, which solves the problems of various defects in existing early warning devices.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a safety early warning device for coal seam fracturing caused by electric pulse in underground coal mines, comprising a sealing device, characterized in that: a capsule section is provided in the middle of the sealing device, an installation ring is fixedly connected to the bottom of the capsule section, an early warning device body is fixedly connected to the outer end of the installation ring, a fixing ring is fixedly connected to the middle and upper ends of the capsule section, a preset circuit is fixedly connected to the outer end of the fixing ring, and a connecting wire is installed through the top of the early warning device body, and the connecting wire is installed through the interior of the preset circuit;

[0008] The outermost end of the warning device body is provided with a wear-resistant layer, the innermost end of the warning device body is provided with an inner lining shielding layer, a structural heat-conducting layer is provided in the middle of the wear-resistant layer and the inner lining shielding layer, and an installation frame is fixedly connected to the inner middle of the warning device body.

[0009] A sensing and detection module is fixedly connected to the lower end of the mounting frame, a signal processing and early warning analysis module is fixedly connected to the middle part of the mounting frame, a linkage control module is fixedly connected to the top of the mounting frame, and a probe is installed at the bottom of the early warning device body.

[0010] Preferably, the sensing and detection module includes:

[0011] The acoustic emission detection unit includes an acoustic emission sensor and a waveguide rod coupled thereto. One end of the waveguide rod is in close contact with the inner wall of the early warning device body, and the other end is connected to the acoustic emission sensor, which is used to transmit the vibration signal of the coal body to the sensor.

[0012] The electromagnetic radiation detection unit includes an electromagnetic radiation sensor, whose sensing antenna is coupled to the metal part of the warning device body, and the warning device body itself constitutes part of the sensing antenna.

[0013] The temperature detection unit includes a temperature sensor, whose sensing head is connected to the inner wall of the warning device body through a highly thermally conductive material.

[0014] Preferably, the signal processing and early warning analysis module includes:

[0015] The signal conditioning unit consists of multiple parallel filter circuits and amplifier circuits, and is used to receive and preprocess the raw analog signals output by the acoustic emission detection unit, electromagnetic radiation detection unit, and temperature detection unit.

[0016] A data acquisition unit, connected to the output of the signal conditioning unit, is used to convert analog signals into digital signals;

[0017] The intelligent analysis unit is connected to the data acquisition unit and stores a multi-parameter fusion early warning algorithm program. The algorithm program is configured to: extract features from the converted digital signal, and perform real-time analysis of acoustic emission, electromagnetic radiation, temperature and gas concentration signals from the orifice gas sensor, and output the risk level based on a preset threshold model.

[0018] Preferably, the linkage control module includes:

[0019] The early warning output unit is connected to the intelligent analysis unit and is used to drive the intrinsically safe audible and visual alarm to issue an audio-visual alarm corresponding to the risk level.

[0020] A relay control unit, connected to the intelligent analysis unit, has its internal relay normally closed contacts configured to be connected in series to the main power supply circuit of the electrical pulse rupture device. When a high-risk command is received, the relay actuates to cut off the power supply circuit.

[0021] Preferably, a sealing ring is fixedly connected to the upper end of the sealing device, and the connecting line passes through the inside of the sealing ring.

[0022] Preferably, a conduit is installed through the top of the sealing device, and a handle is fixedly connected to the conduit.

[0023] Preferably, the open end of the conduit is equipped with a connecting flange for connection to the infusion equipment.

[0024] Preferably, the inside of the warning device body is filled with thermally conductive insulating adhesive to fix internal components, enhance heat dissipation, and improve impact resistance.

[0025] Working principle: During operation, the sealing device 1, which integrates the early warning device body 7, is inserted into the predetermined depth of the borehole. High-pressure medium is injected into the capsule section 4 through the conduit 12 to cause it to expand, thereby sealing the borehole and forcing the probe 6 at the front end of the early warning device body 7 and the shell to be tightly coupled with the coal wall. Subsequently, the electric pulse fracturing equipment is started to operate. During this process, the sensing and detection module 16 integrated inside the early warning device body 7 begins to work. Its acoustic emission detection unit senses the vibration signal generated by coal fracturing through the waveguide rod, the electromagnetic radiation detection unit senses the electromagnetic signal released by stress changes through the shell antenna, and the temperature detection unit monitors the temperature change of the coal body in real time. These raw signals are transmitted to the signal processing and early warning analysis module 15 through the connecting line 9 in the preset line 8. The signal of this module... The conditioning unit first filters and amplifies the multiple signals for preprocessing, then the data acquisition unit converts them into digital signals. Finally, the intelligent analysis unit runs a multi-parameter fusion algorithm to comprehensively analyze the real-time changes in characteristics such as acoustic emission, electromagnetic radiation, temperature, and orifice gas concentration, and identifies the risk level based on a preset threshold model. Once the risk level is determined to exceed the safety threshold, the intelligent analysis unit immediately instructs the linkage control module 13 to act. Its early warning output unit drives the underground audible and visual alarm to issue a strong warning, while the relay control unit cuts off the main power supply circuit of the electrical pulse fracturing equipment. This achieves fully automated safety protection from real-time perception and intelligent analysis to advanced early warning and active power cut-off, greatly improving the prevention and control capabilities of underground coal mine dynamic disasters.

[0026] (III) Beneficial Effects

[0027] This invention provides a safety early warning device for coal seam fracturing caused by electrical pulses in underground coal mines. It possesses the following features:

[0028] Beneficial effects:

[0029] 1. This invention integrates the safety early warning module with the borehole sealer into a single structure, directly installing it on the outer end of the capsule and entering the core area of ​​the borehole fracturing process with it. This breaks through the traditional mode of independent installation of monitoring equipment, realizing source-level safety monitoring, enabling the sensor to achieve optimal coupling with the coal body, and directly acquiring the most original and cutting-edge physical information of the fracturing process, providing a solid foundation for advanced early warning. Secondly, it realizes the simultaneous completion of borehole sealing operations and monitoring system deployment, simplifying the downhole operation process and improving the engineering practicality and reliability of the system.

[0030] 2. This invention integrates multiple sensors, such as acoustic emission, electromagnetic radiation, and temperature sensors, to form a collaborative monitoring capability of multiple physical fields in the fracturing process. On the one hand, by comprehensively utilizing various precursory information, it overcomes the shortcomings of single-parameter monitoring, which is prone to false alarms and missed alarms, and significantly improves the accuracy of risk identification. On the other hand, by using built-in algorithms to intelligently and comprehensively identify multi-source information, it realizes a rapid response across the entire chain from automatic risk identification to active power cut-off, transforming safety protection from passive response to active intervention. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the coal mine underground electrical pulse-induced coal seam safety early warning device proposed in this invention;

[0032] Figure 2 This is a top view of the coal mine underground electrical pulse-induced fracturing coal seam safety early warning device proposed in this invention.

[0033] Figure 3 This is a schematic diagram of the internal structure of the early warning device for the underground coal seam safety early warning device induced by electrical pulse fracturing proposed in this invention.

[0034] Figure 4 This is a schematic diagram of the structure of the warning device housing of the underground coal seam safety warning device induced by electrical pulse fracturing proposed in this invention.

[0035] The components include: 1. Sealing device; 2. Sealing ring; 3. Fixing ring; 4. Capsule segment; 5. Mounting ring; 6. Probe; 7. Warning device body; 8. Preset circuit; 9. Connecting wire; 10. Connecting flange; 11. Handle; 12. Conduit; 13. Linkage control module; 14. Mounting frame; 15. Signal processing and early warning analysis module; 16. Sensing and detection module; 17. Structural heat-conducting layer; 18. Inner lining shielding layer; 19. Wear-resistant layer. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example:

[0038] like Figure 1-4As shown, this embodiment of the invention provides a safety early warning device for coal seams fractured by electric pulse in underground coal mines, including a sealing device 1. A capsule section 4 is provided in the middle of the sealing device 1. An installation ring 5 is fixedly connected to the bottom of the capsule section 4. An early warning device body 7 is fixedly connected to the outer end of the installation ring 5. Fixing rings 3 are fixedly connected to the middle and upper ends of the capsule section 4. A preset circuit 8 is fixedly connected to the outer end of the fixing ring 3. A connecting wire 9 is installed through the top of the early warning device body 7, and the connecting wire 9 passes through the interior of the preset circuit 8. The sealing device 1 is made of 30CrMnSiA high-strength alloy steel, which has a tensile strength ≥1080MPa and a yield strength of ≥1080MPa. With a strength ≥835MPa, it can withstand downhole impact loads and corrosive environments. As the load-bearing skeleton of the device, it integrates capsule section 4, fixing ring 3 and sealing ring 2, providing a stable installation foundation for the early warning device body 7. Capsule section 4 is made of hydrogenated nitrile rubber, which is oil-resistant and high-pressure resistant and suitable for complex downhole media environments. The two ends of capsule section are fixed to the sealing device body through vulcanization bonding process, with a bonding strength ≥5MPa. At the same time, it is reinforced with M4 stainless steel countersunk bolts to prevent it from falling off when high-pressure media is injected. By injecting high-pressure media, it expands to achieve borehole sealing and presses the early warning device body 7 tightly against the coal wall to ensure effective transmission of sensing signals.

[0039] The outermost end of the warning device body 7 is provided with a wear-resistant layer 19, and the innermost end of the warning device body 7 is provided with an inner lining shielding layer 18. A structural heat-conducting layer 17 is provided between the wear-resistant layer 19 and the inner lining shielding layer 18. A mounting frame 14 is fixedly connected to the inner middle of the warning device body 7. A sensing and detection module 16 is fixedly connected to the lower end of the mounting frame 14. A signal processing and early warning analysis module 15 is fixedly connected to the middle of the mounting frame 14. A linkage control module 13 is fixedly connected to the top of the mounting frame 14. A probe 6 is installed at the bottom of the warning device body 7. The wear-resistant layer 19 is made of tungsten carbide WC coating, prepared by plasma spraying, to resist wear and collision of coal and rock particles underground, extend the service life of the device, and ensure that it does not peel off during long-term use. The heat-conducting layer 17 is made of aluminum alloy 606. 1. After extrusion molding, anodizing is performed to provide structural support for the internal modules and to dissipate the heat from the modules and the coal, preventing overheating of the components. The inner lining shielding layer 18 is made of permalloy and bonded to the inner wall of the structural heat-conducting layer with epoxy resin to shield against strong electromagnetic interference in the mine and ensure that the signal-to-noise ratio of the sensing signal is ≥40dB. Secondly, the inside of the early warning device body 6 is filled with silicone thermally conductive adhesive and vacuum potting process to fix the internal components to prevent vibration displacement, enhance the heat dissipation module temperature rise ≤15℃, and improve the impact resistance performance impact acceleration ≥1500g. Furthermore, the probe 6 serves as the "transmission window" for sensing signals, efficiently transmitting the vibration and temperature signals of the coal to the detection unit inside the early warning device body. The ceramic material ensures that it will not break under the pressure of the coal wall.

[0040] The sensing module 16 includes:

[0041] The acoustic emission detection unit includes an acoustic emission sensor and a waveguide rod coupled thereto. One end of the waveguide rod is in close contact with the inner wall of the early warning device body 7, and the other end is connected to the acoustic emission sensor to transmit the vibration signal of the coal body to the sensor.

[0042] The electromagnetic radiation detection unit includes an electromagnetic radiation sensor, whose sensing antenna is coupled to the metal part of the warning device body 7, and the warning device body 7 itself constitutes part of the sensing antenna.

[0043] The temperature detection unit includes a temperature sensor, whose sensing head is connected to the inner wall of the warning device body 7 through a highly thermally conductive material.

[0044] Signal processing and early warning analysis module 15 includes:

[0045] The signal conditioning unit consists of multiple parallel filter circuits and amplifier circuits, and is used to receive and preprocess the raw analog signals output by the acoustic emission detection unit, electromagnetic radiation detection unit, and temperature detection unit.

[0046] The data acquisition unit, connected to the output of the signal conditioning unit, is used to convert analog signals into digital signals;

[0047] The intelligent analysis unit, connected to the data acquisition unit, stores a multi-parameter fusion early warning algorithm program. The algorithm program is configured to: extract features from the converted digital signal, and perform real-time analysis of acoustic emission, electromagnetic radiation, temperature, and gas concentration signals from the orifice gas sensor, and output the risk level based on a preset threshold model.

[0048] The linkage control module 13 includes:

[0049] The early warning output unit, connected to the intelligent analysis unit, is used to drive the intrinsically safe audible and visual alarm to issue an audio-visual alarm corresponding to the risk level;

[0050] The relay control unit is connected to the intelligent analysis unit. The normally closed contacts of the relays inside the unit are configured to be connected in series to the main power supply circuit of the electrical pulse rupture device. When a high-risk command is received, the relays will activate to cut off the power supply circuit.

[0051] A sealing ring 2 is fixedly connected to the upper end of the sealing device 1, and the connecting line 9 passes through the inside of the sealing ring 2. A conduit 12 is installed through the top of the sealing device 1, and a handle 11 is fixedly connected to the conduit 12. A connecting flange 10 is installed at the open end of the conduit 12 for connecting to external pressure filling equipment. The inside of the warning device body 7 is filled with thermally conductive insulating glue to fix internal components, enhance heat dissipation, and improve impact resistance. The preset line uses an armored cable with the same length as the conduit 12 and is fixed in the slot of the fixing ring 3. The connecting line 9 uses a multi-core shielded wire that passes through the inside of the preset line 8. One end is welded to the internal module of the warning device body 7, and the other end is connected to the ground monitoring system to transmit sensor signals, control commands, and power supply. The shielding layer is connected to the inner lining shielding layer 18 of the warning device body to achieve full-link electromagnetic shielding.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A safety early warning device for coal seam fracturing caused by electrical pulse in underground coal mines, comprising a sealing device (1), characterized in that: The sealing device (1) has a capsule section (4) in the middle. A mounting ring (5) is fixedly connected to the bottom of the capsule section (4). The outer end of the mounting ring (5) is fixedly connected to the warning device body (7). The middle and upper ends of the capsule section (4) are fixedly connected to a fixing ring (3). The outer end of the fixing ring (3) is fixedly connected to a preset line (8). A connecting line (9) is installed through the top of the warning device body (7), and the connecting line (9) is installed through the interior of the preset line (8). The outermost end of the warning device body (7) is provided with a wear-resistant layer (19), the innermost end of the warning device body (7) is provided with an inner lining shielding layer (18), the middle part of the wear-resistant layer (19) and the inner lining shielding layer (18) is provided with a structural heat-conducting layer (17), and the middle part of the inner side of the warning device body (7) is fixedly connected with an installation frame (14). The lower end of the mounting frame (14) is fixedly connected to a sensing and detection module (16), the middle part of the mounting frame (14) is fixedly connected to a signal processing and early warning analysis module (15), the top of the mounting frame (14) is fixedly connected to a linkage control module (13), and the bottom of the early warning device body (7) is equipped with a probe (6).

2. The coal mine underground electrical pulse-induced fracturing coal seam safety early warning device according to claim 1, characterized in that: The sensing module (16) includes: The acoustic emission detection unit includes an acoustic emission sensor and a waveguide rod coupled thereto. One end of the waveguide rod is in close contact with the inner wall of the early warning device body (7), and the other end is connected to the acoustic emission sensor, which is used to transmit the vibration signal of the coal body to the sensor. The electromagnetic radiation detection unit includes an electromagnetic radiation sensor, whose sensing antenna is coupled to the metal part of the warning device body (7), and the warning device body (7) itself constitutes part of the sensing antenna. The temperature detection unit includes a temperature sensor, whose temperature sensing head is connected to the inner wall of the warning device body (7) through a highly thermally conductive material.

3. The coal mine underground electrical pulse-induced fracturing coal seam safety early warning device according to claim 2, characterized in that: The signal processing and early warning analysis module (15) includes: The signal conditioning unit consists of multiple parallel filter circuits and amplifier circuits, and is used to receive and preprocess the raw analog signals output by the acoustic emission detection unit, electromagnetic radiation detection unit, and temperature detection unit. A data acquisition unit, connected to the output of the signal conditioning unit, is used to convert analog signals into digital signals; The intelligent analysis unit is connected to the data acquisition unit and stores a multi-parameter fusion early warning algorithm program. The algorithm program is configured to: extract features from the converted digital signal, and perform real-time analysis of acoustic emission, electromagnetic radiation, temperature and gas concentration signals from the orifice gas sensor, and output the risk level based on a preset threshold model.

4. The underground coal seam safety early warning device induced by electrical pulse fracturing according to claim 3, characterized in that: The linkage control module (13) includes: The early warning output unit is connected to the intelligent analysis unit and is used to drive the intrinsically safe audible and visual alarm to issue an audio-visual alarm corresponding to the risk level. A relay control unit, connected to the intelligent analysis unit, has its internal relay normally closed contacts configured to be connected in series to the main power supply circuit of the electrical pulse rupture device. When a high-risk command is received, the relay actuates to cut off the power supply circuit.

5. The coal mine underground electrical pulse-induced fracturing coal seam safety early warning device according to claim 1, characterized in that: The upper end of the sealing device (1) is fixedly connected to a sealing ring (2), and the connecting line (9) passes through the interior of the sealing ring (2).

6. The coal mine underground electrical pulse-induced fracturing coal seam safety early warning device according to claim 1, characterized in that: The top of the sealing device (1) is fitted with a conduit (12), and a handle (11) is fixedly connected to the conduit (12).

7. The coal mine underground electrical pulse-induced fracturing coal seam safety early warning device according to claim 6, characterized in that: The open end of the conduit (12) is fitted with a connecting flange (10) for connection to external pressure filling equipment.

8. The underground coal seam safety early warning device for electrical pulse-induced fracturing according to claim 1, characterized in that: The body (7) of the early warning device is filled with thermally conductive insulating glue to fix internal components, enhance heat dissipation and improve impact resistance.

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