Dynamic regulation device and method for high-efficiency extraction of roof fracture zone directional long borehole

Abstract

This invention provides a dynamic control device and method for efficient extraction of gas from directional long boreholes in roof fracture zones. The method calculates the mixed flow rate of the extracted gas using the orifice flow coefficient of the orifice flow meter and the monitored pressure difference across the orifice. Based on the methane concentration monitored by the methane sensor, the pure gas extraction quantity is calculated. During the drilling extraction process, the extraction negative pressure is adjusted by regulating the opening angle of an adjustable electrically controlled valve at set time intervals. The negative pressure at the orifice when the pure extraction quantity of each directional long borehole in the roof fracture zone is maximized is determined. Then, the opening degree of the adjustable electrically controlled valve is adjusted using a PLC to adjust the extraction negative pressure of all boreholes to the value at which the pure extraction quantity is maximized, thereby optimizing extraction efficiency. This invention enables unified control of all directional long boreholes in roof fracture zones within a drilling site, effectively improving extraction efficiency and ensuring safe mining of the working face.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal mine roof fracture zone directional long borehole gas extraction, and particularly relates to a roof fracture zone directional long borehole efficient extraction dynamic regulation device and method. BACKGROUND

[0002] Gas emission is one of the important factors threatening the safety production of coal mines. Influenced by mining, a large number of fractures are generated in the overburden strata of the coal seam roof, which increases the gas permeability of the strata and significantly enhances the gas passing rate. The "gas channel" formed by the overburden strata fractures makes the gas move along the fractures and form a gas enrichment zone. Due to the limitation of the channel shape, a secondary vortex will inevitably be formed at the upper corner. With the generation of the secondary vortex, the gas flow velocity slows down, the gas in the vortex cannot flow out in time, and the gas accumulates, causing the gas concentration in the upper corner and the return airway to exceed the limit, affecting the safety of the coal mining face construction.

[0003] Various control measures have been proposed to address the problem of gas concentration exceeding the limit in the upper corner and the return airway, mainly including high extraction roadway, high-position borehole, buried pipe extraction, etc. The high extraction roadway has high extraction efficiency, but the engineering quantity is large, the construction period is long, and the cost is high. The high-position borehole extraction is relatively more economical, but when the conventional drilling machine is used for high-position borehole construction, the drilling trajectory is not controlled, and is influenced by geological conditions and gravity, etc. The drilling trajectory is mostly parabolic, the invalid hole section is long, and the extraction effect is general. The coal seam roof fracture zone directional long borehole has the characteristics of accurate control of drilling trajectory, high hole forming efficiency, short construction period, and good extraction effect, and can be constructed in the return airway drilling field of the working face, so the cost is low. Therefore, the coal seam roof fracture zone directional long borehole gas extraction technology has been widely applied.

[0004] In the application of coal seam roof fracture zone directional long borehole gas extraction, according to the site geological conditions, the length of each directional borehole is generally 500-600 m, and according to the gas emission conditions, 3-8 boreholes are generally constructed in each drilling field. After the borehole construction is completed and the hole is sealed, the extraction pipe network is directly connected for extraction. In the extraction process, a constant extraction negative pressure is often used for extraction in each coal mine. However, research has found that with the increase of the gas extraction time, the flow law of the gas in the coal seam will inevitably change, so it is not reasonable to use a constant extraction negative pressure under different gas flow conditions. SUMMARY

[0005] Based on the above problems, the present application proposes a roof fracture zone directional long borehole efficient extraction dynamic regulation device and method. By uniformly controlling the multiple fracture zone directional long boreholes in one drilling field, monitoring and analyzing the extraction data of each borehole, adjusting the extraction negative pressure of each borehole, making the extraction amount and methane concentration of the borehole reach the best match, and making the extraction pure amount reach the maximum, the extraction efficiency of the whole drilling field can be optimized.

[0006] In order to achieve the above-mentioned purpose, the application provides a roof fracture zone directional long borehole efficient extraction dynamic regulation device, which comprises a pipeline monitoring device and a pipeline control device; the pipeline monitoring device comprises a rubber connecting hose, a negative pressure sensor, an adjustable electric control valve, a differential pressure sensor, an orifice flowmeter, a methane concentration sensor and a seamless steel pipe; one end of the rubber connecting hose is connected with the fracture zone directional long borehole through a flange, and the other end is connected with the seamless steel pipe through a flange; the negative pressure sensor, the adjustable electric control valve, the orifice flowmeter and the methane concentration sensor are sequentially connected or arranged on the seamless steel pipe outward from the borehole; and the differential pressure port of the orifice flowmeter is connected with the differential pressure sensor; the pipeline control device comprises a PLC, an AD conversion module, a DA conversion module, a display screen and a remote transmission module; the PLC is connected with the output end of the AD conversion module, the input end of the DA conversion module, the input end of the display screen and the input end of the remote transmission module; the input end of the AD conversion module is connected with the negative pressure sensor, the differential pressure sensor and the methane concentration sensor in the pipeline monitoring device; the output end of the DA conversion module is connected with the adjustable electric control valve in the pipeline monitoring device; and the output end of the remote transmission module is connected with an industrial ring network switch in a well.

[0007] Further, at least three roof fracture zone directional long boreholes are constructed in a single drilling field; the AD conversion module is provided with at least nine analog signal input ports, which are connected with nine sensors (including a negative pressure sensor, a methane concentration sensor and a differential pressure sensor) arranged on the pipeline of each borehole; the digital signal output port of the AD conversion module is connected with the PLC; and the analog signal of the sensor is converted into a digital signal and then transmitted to the PLC; the DA conversion module is provided with at least three analog signal output ports, which are connected with the adjustable electric control valves arranged on the pipeline of each borehole; the digital signal input port of the DA conversion module is connected with the PLC; and the output digital signal of the PLC is converted into an analog signal by the DA conversion module, so as to drive the adjustable electric control valve to adjust the valve angle.

[0008] Further, the mixed gas extracted from the roof fracture zone directional long borehole enters the seamless steel pipe extraction pipeline through the rubber hose; the negative pressure sensor monitors the borehole extraction negative pressure in real time; the adjustable electric control valve can adjust the borehole extraction negative pressure by adjusting the valve opening angle; the mixed flow of the extraction gas is determined by the differential pressure value monitored by the differential pressure sensor and the orifice coefficient of the orifice flowmeter; the methane concentration in the extraction mixed gas is measured by the methane concentration sensor; the PLC calculates the gas extraction purity based on the measured mixed flow and methane concentration and uploads the result to the display screen; and the display screen displays the monitoring data of each sensor in real time.

[0009] Further, the PLC drives the opening and closing degree of the adjustable electric control valve through the DA conversion module to adjust the orifice negative pressure, and the gas extraction quantity under different orifice negative pressure conditions is obtained, the orifice negative pressure corresponding to the maximum gas extraction quantity is the optimal orifice extraction negative pressure, and the extraction efficiency optimization of the roof fracture zone directional long borehole is realized.

[0010] Further, the negative pressure sensor, the adjustable electric control valve, the differential pressure sensor, the methane concentration sensor and the orifice plate flowmeter in the pipeline monitoring device are mine-used intrinsically safe devices.

[0011] Further, the PLC, the AD conversion module, the DA conversion module, the display screen and the remote transmission module in the pipeline control device are intrinsically safe, and are placed in the intrinsically safe PLC control box.

[0012] Further, the number of boreholes in the same drilling field is not limited to three, and when more than three, only the number of pipeline monitoring devices needs to be added and the number of AD conversion module and DA conversion module ports in the pipeline control device needs to be increased.

[0013] The application provides a kind of roof fracture zone directional long borehole high-efficiency extraction dynamic regulation and control method, which is realized based on the kind of roof fracture zone directional long borehole high-efficiency extraction dynamic regulation and control device, and the regulation and control method comprises:

[0014] Step 1, drill field is constructed in the downhole working face return air groove, and roof fracture zone directional long borehole is constructed in the drill field according to requirements, after the completion of borehole construction, the borehole is sealed by using cement mortar, and then the flange plate is connected with the rubber connecting hose of the pipeline monitoring device;

[0015] Step 2, the mixed gas in the borehole enters the seamless steel pipe through the rubber connecting hose under the action of extraction negative pressure, the negative pressure sensor monitors the orifice negative pressure in real time, the methane concentration sensor monitors the methane concentration in the extracted mixed gas in real time, and the differential pressure sensor monitors the pressure difference between the two ends of the orifice plate flowmeter in real time;

[0016] Step 3, the AD conversion module converts the analog data monitored by various sensors into digital signals and transmits them into the PLC, the PLC displays the monitored data on the display screen in real time, the PLC calculates the flow of the extracted mixed gas according to the orifice plate flow coefficient and the monitored pressure difference between the two ends of the orifice plate, calculates the gas extraction quantity in the extracted gas according to the methane concentration value monitored by the methane concentration sensor, and displays the result on the display screen; at the same time, the PLC connects all the real-time monitored and calculated data to the mine ring network switch through the remote transmission module, for data collection by the ground system.

[0017] Step 4, PLC controls the adjustable electric control valve through the DA conversion module within a set time, so that the opening and closing degree is adjusted from 0 degree to 90 degrees, and the adjustment step is 1 degree; each drainage borehole needs to be adjusted separately, and when adjusting, other boreholes are in a closed state; when the adjustable electric control valve is adjusted by 1 degree, the PLC records the orifice drainage negative pressure, the flow of the extracted mixed gas, the methane concentration in the extracted mixed gas and the gas drainage pure volume under the current valve opening and closing degree;

[0018] Step 5, step 4 is repeated, and the valve opening and closing degree and the corresponding drainage negative pressure, mixed gas flow and gas drainage pure volume under the opening and closing degree are recorded for each roof fracture zone directional long borehole;

[0019] Step 6, for each roof fracture zone directional long borehole, the PLC compares the orifice drainage negative pressure and the gas drainage pure volume value corresponding to each angle in the adjustment process of the adjustable electric control valve from 0 to 90 degrees, and determines the orifice drainage negative pressure corresponding to the maximum gas drainage pure volume; the information is displayed on the display screen and transmitted into the mine ring network switch through the remote transmission module;

[0020] Step 7, the PLC adjusts the orifice drainage negative pressure of all roof fracture zone directional long boreholes to the orifice drainage negative pressure corresponding to the maximum gas drainage pure volume of each borehole by adjusting the adjustable electric control valve through the DA conversion module, so as to realize the optimization of the drainage efficiency in the current set time period;

[0021] Step 8, when the time reaches the next set time, the PLC will repeat the process of steps 4 to 7 to realize the optimization of the drainage efficiency in the next time period.

[0022] The beneficial effects of the present application are:

[0023] The present application provides a roof fracture zone directional long borehole efficient drainage dynamic regulation and control device and method, a negative pressure sensor, an adjustable electric control valve, an orifice plate flowmeter, a methane concentration sensor and a differential pressure sensor are arranged on a seamless steel pipe, the orifice plate flowmeter is used for calculating the mixed gas flow by the orifice plate flow coefficient and the monitored pressure difference between the orifice plate, the gas drainage pure volume in the mixed gas is calculated according to the methane concentration value monitored by the methane concentration sensor, in the process of borehole drainage, the drainage negative pressure is adjusted by adjusting the opening and closing angle of the adjustable electric control valve at a set time interval, the orifice drainage negative pressure when the drainage pure volume of each roof fracture zone directional long borehole is maximum is determined, and then the opening and closing degree of the adjustable electric control valve is adjusted by the PLC, so that the drainage negative pressure of all boreholes is adjusted to the negative pressure value when the drainage pure volume is maximum, so as to realize the optimization of the drainage efficiency, the present application can uniformly control all roof fracture zone directional long boreholes in a drilling field, can effectively improve the drainage efficiency and ensure the safe recovery of the working face. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 It is a structure schematic diagram of the dynamic regulation device for the roof fracture zone directional long borehole high-efficiency extraction in the application;

[0025] Fig. 2 It is an internal function structure schematic diagram of the pipeline control device in the application;

[0026] In the figure, 1, rubber connecting hose; 2, flange plate; 3, negative pressure sensor; 4, adjustable electric control valve; 5, differential pressure sensor; 6, orifice flowmeter; 7, methane concentration sensor; 8, seamless steel pipe; 9, intrinsically safe PLC control box; 10, display screen; 11, PLC; 12, AD conversion module; 13, DA conversion module; 14, remote transmission module; 15, mine extraction pipe network. DETAILED DESCRIPTION

[0027] The application will be further described below in combination with the drawings and specific implementation examples.

[0028] As Figs. 1-2 shown, the application provides a dynamic regulation device for the roof fracture zone directional long borehole high-efficiency extraction, which comprises a pipeline monitoring device and a pipeline control device; the pipeline monitoring device comprises a rubber connecting hose 1, a flange plate 2, a negative pressure sensor 3, an adjustable electric control valve 4, a differential pressure sensor 5, an orifice flowmeter 6, a methane concentration sensor 7, and a seamless steel pipe 8; one end of the rubber connecting hose 1 is connected with the fracture zone directional long borehole through the flange plate 2, and the other end is connected with the seamless steel pipe 8 through the flange plate 2; the negative pressure sensor 3, the adjustable electric control valve 4, the orifice flowmeter 6, and the methane concentration sensor 7 are sequentially connected or arranged on the seamless steel pipe 8 outward from the borehole; the differential pressure port of the orifice flowmeter 6 is connected with the differential pressure sensor 5, and the differential pressure sensor is installed at the differential pressure port of the orifice flowmeter 6; there are two small holes on the orifice flowmeter, which are used for monitoring the differential pressure before and after the orifice; the differential pressure sensor has two pressure input ports, which are connected with the two small holes on the orifice flowmeter, and are used for monitoring the differential pressure before and after the orifice in the orifice flowmeter; the differential pressure value can be used to calculate the gas flow through the orifice flowmeter.

[0029] The pipeline control device comprises a PLC 11, an AD conversion module 12, a DA conversion module 13, a display screen 10, and a remote transmission module 14; the PLC 11 is the main control core, and is connected with the output end of the AD conversion module 12, the input end of the DA conversion module 13, the input end of the display screen 10, and the input end of the remote transmission module 14; the input end of the AD conversion module 12 is connected with the negative pressure sensor 3, the differential pressure sensor 5, and the methane concentration sensor 7 in the pipeline monitoring device; the output end of the DA conversion module 13 is connected with the adjustable electric control valve 4 in the pipeline monitoring device; and the output end of the remote transmission module 14 is connected with an industrial ring network switch in the underground mine.

[0030] At least three directional long boreholes with roof fracture zones are constructed within a single drilling site. The AD conversion module 12 is equipped with at least nine analog signal input ports, which are connected to nine sensors installed on the three borehole pipelines. The digital signal output port of the AD conversion module 12 is connected to the PLC 11, converting the analog signals output by the sensors into digital signals and transmitting them to the PLC 11. The DA conversion module 13 is equipped with at least three analog signal output ports, which are connected to adjustable electrically controlled valves 4 installed on the three borehole pipelines. The digital signal input port of the DA conversion module 13 is connected to the PLC 11. The digital signals output by the PLC 11 are converted into analog signals by the DA conversion module 13, which then drive the adjustable electrically controlled valves 4 to adjust the valve angle.

[0031] The mixed gas extracted from the directional long borehole in the roof fracture zone enters the extraction pipeline connected to the seamless steel pipe 8 through the rubber connecting hose 1. The negative pressure sensor 3 monitors the extraction negative pressure at the borehole in real time. The adjustable electric control valve 4 can adjust the extraction negative pressure at the borehole by adjusting the valve opening angle. The flow rate of the extracted mixed gas is calculated by the orifice plate flow meter 6 and the differential pressure sensor 5. The calculation formula is as follows: In the formula, Q is the flow rate of the extracted mixed gas, K is the coefficient after calibration of the orifice plate flowmeter 6, and ΔP is the pressure difference before and after the orifice plate of the orifice plate flowmeter monitored by the differential pressure sensor. The methane concentration in the extracted mixed gas is measured by the methane concentration sensor 7. PLC11 calculates the gas extraction purity based on the measured flow rate of the extracted mixed gas and the methane concentration in the mixed gas. The calculation formula is: Q 纯 =Q·C, where Q 纯 Q represents the pure gas extraction rate, C represents the flow rate of the extracted mixed gas, and Q represents the methane concentration in the mixed gas. Display screen 10 shows the monitoring data from each sensor in real time.

[0032] PLC11 drives the adjustable electronically controlled valve 4 through DA conversion module 13 to adjust the opening and closing degree, thereby adjusting the negative pressure at the orifice, obtaining the gas extraction volume under different orifice negative pressure conditions, and finally determining the optimal orifice extraction negative pressure to optimize the extraction efficiency of directional long boreholes in the roof fracture zone.

[0033] In this embodiment, the negative pressure sensor 3, adjustable electrically controlled valve 4, differential pressure sensor 5, orifice flow meter 6, and methane concentration sensor 7 in the pipeline monitoring device are all intrinsically safe devices for mining.

[0034] In this embodiment, the PLC11, AD conversion module12, DA conversion module13, display screen10, and remote transmission module14 in the pipeline control device are all intrinsically safe and are placed in an intrinsically safe PLC control box 9.

[0035] In this embodiment, the number of boreholes in the same drilling site is not limited to three. If there are more than three, it is only necessary to increase the number of pipeline monitoring devices and the number of ports of AD conversion module 12 and DA conversion module 13 in the pipeline control device.

[0036] This invention provides a dynamic control method for efficient extraction from directional long boreholes in roof fracture zones, based on the aforementioned dynamic control device for efficient extraction from directional long boreholes in roof fracture zones. The control method includes:

[0037] Step 1: Construct a drilling site in the return air roadway of the underground working face. Construct directional long boreholes in the roof crack zone as required within the drilling site. After the boreholes are completed, seal them with cement mortar. Then connect them to the rubber connecting hose 1 of the pipeline monitoring device through flange 2.

[0038] Step 2: Under the action of extraction negative pressure, the mixed gas in the borehole enters the seamless steel pipe 8 through the rubber connecting hose 1. The negative pressure sensor 3 monitors the negative pressure at the borehole opening in real time, the methane concentration sensor 7 monitors the methane concentration of the extracted mixed gas in real time, and the differential pressure sensor 5 monitors the pressure difference across the orifice plate of the orifice plate flow meter 6 in real time.

[0039] Step 3: The AD conversion module 12 (EM AQ series AD conversion module) converts the analog data monitored in real time by various sensors into digital signals and then transmits them to the PLC11 (SIEMNES S7-200 Smart PLC). The PLC11 displays the monitored data on the display screen 10 in real time. The PLC11 calculates the flow rate of the extracted mixed gas using the orifice flow coefficient of the orifice flow meter 6 and the pressure difference value collected by the differential pressure sensor 5 across the orifice. The calculation formula is as follows: In the formula, Q is the flow rate of the extracted mixed gas, K is the coefficient after calibration of the orifice plate flowmeter 6, ΔP is the pressure difference before and after the orifice plate of the orifice plate flowmeter monitored by the differential pressure sensor, and the gas extraction purity is calculated using the methane concentration in the extracted mixed gas monitored by the methane concentration sensor 7. The calculation formula is: Q 纯 =Q·C, where Q 纯 The value is: Q = methane extraction volume, Q = flow rate of the extracted mixed gas, and C = methane concentration in the extracted mixed gas. These values ​​are displayed on the display screen 10. Simultaneously, PLC 11 connects all real-time monitored and calculated data to the mine ring network switch via remote transmission module 14 for data acquisition by the ground remote monitoring system.

[0040] Step 4: PLC11 controls the adjustable electrically controlled valve 4 via DA conversion module 13 at a set time (manually set, generally every 24 hours), adjusting its opening degree from 0 degrees to 90 degrees, with an adjustment step of 1 degree. Each extraction borehole needs to be adjusted individually; during adjustment, other boreholes are in the closed state. For each degree adjustment of the adjustable electrically controlled valve 4, PLC11 records the orifice extraction negative pressure, the flow rate of the extracted mixed gas, the methane concentration in the extracted mixed gas, and the pure gas extraction amount at the current valve opening degree.

[0041] Step 5: Record the adjustment, monitoring, and calculation of each directional long borehole in the roof fracture zone according to the method in Step 4; including recording the valve opening degree and the corresponding extraction negative pressure, extraction gas mixed flow rate, and gas extraction purity under that opening degree.

[0042] Step 6: For each directional long borehole in the roof fracture zone, PLC11 compares the borehole extraction negative pressure and gas extraction purity value at each angle during the adjustment process of the adjustable electrically controlled valve 4 from 0 to 90 degrees, and determines the borehole extraction negative pressure corresponding to the maximum gas extraction purity value. This information is displayed on the display screen 10 (MCGS series human-machine interface display screen) and transmitted to the mine ring network switch via the remote transmission module 14.

[0043] Step 7: PLC11, through DA conversion module 13 (EM AQ series DA conversion module), adjusts the adjustable electric control valve 4 to adjust the negative pressure of the extraction at the orifice of all directional long boreholes in the roof crack zone to the negative pressure of the orifice corresponding to the maximum pure gas extraction value of each borehole, so as to optimize the extraction efficiency under the current set time period.

[0044] Step 8: When the time reaches the next set time (manually set, usually 24 hours), PLC11 will repeat the process from Step 4 to Step 7 to optimize the extraction efficiency in the next time period.

Claims

1. A dynamic control device for efficient extraction from directional long boreholes in roof fracture zones, characterized in that, include: The pipeline monitoring device includes a rubber connecting hose, a negative pressure sensor, an adjustable electrically controlled valve, a differential pressure sensor, an orifice flow meter, a methane concentration sensor, and a seamless steel pipe. One end of the rubber connecting hose is connected to a long directional borehole in the fracture zone via a flange, and the other end is connected to the seamless steel pipe via a flange. The seamless steel pipe is sequentially connected or installed with the negative pressure sensor, adjustable electrically controlled valve, orifice flow meter, and methane concentration sensor from the borehole outwards. The differential pressure port of the orifice flow meter is connected to the differential pressure sensor. The pipeline control device includes a PLC, an AD conversion module, a DA conversion module, a display screen, and a remote transmission module. The PLC is connected to the output of the AD conversion module, the input of the DA conversion module, the input of the display screen, and the input of the remote transmission module. The input of the AD conversion module is connected to the negative pressure sensor, differential pressure sensor, and methane concentration sensor in the pipeline monitoring device. The output of the DA conversion module is connected to the adjustable electrically controlled valve in the pipeline monitoring device. The output of the remote transmission module is connected to the downhole industrial ring network switch. The mixed gas extracted from the directional long borehole in the roof fissure zone enters the seamless steel pipe extraction pipeline through a rubber hose. The negative pressure sensor monitors the extraction negative pressure at the borehole in real time. The adjustable electric control valve can adjust the extraction negative pressure at the borehole by adjusting the valve opening angle. The mixed flow rate of the extracted gas is determined by the differential pressure value monitored by the differential pressure sensor and the orifice coefficient of the orifice plate flow meter. The methane concentration in the extracted mixed gas is measured by the methane concentration sensor. The PLC calculates the pure gas extraction volume by measuring the mixed flow rate and methane concentration and uploads it to the display screen. The display screen displays the monitoring data of each sensor in real time. The PLC drives the adjustable electric control valve to adjust the opening and closing degree through the DA conversion module, thereby adjusting the orifice negative pressure and obtaining the gas extraction purity under different orifice negative pressure conditions. The orifice negative pressure corresponding to the maximum gas extraction purity is the optimal orifice extraction negative pressure, thereby optimizing the extraction efficiency of the directional long borehole in the roof fracture zone.

2. The dynamic control device for efficient extraction from directional long boreholes in roof fracture zones according to claim 1, characterized in that, At least three directional long boreholes with roof fracture zones are drilled within a single drilling site. The AD conversion module is equipped with at least nine analog signal input ports, which are connected to nine sensors installed on the three borehole pipelines. The digital signal output port of the AD conversion module is connected to the PLC to convert the analog signals from the sensors into digital signals and transmit them to the PLC. The DA conversion module is equipped with at least three analog signal output ports, which are connected to adjustable electrically controlled valves installed on the three borehole pipelines. The digital signal input port of the DA conversion module is connected to the PLC. The digital signals output by the PLC are converted into analog signals by the DA conversion module and then drive the adjustable electrically controlled valves to adjust the valve angle.

3. The dynamic control device for efficient extraction from directional long boreholes in roof fracture zones according to claim 1, characterized in that, The negative pressure sensor, adjustable electrically controlled valve, differential pressure sensor, methane concentration sensor, and orifice plate flow meter in the pipeline monitoring device are all intrinsically safe devices for mining.

4. The dynamic control device for efficient extraction from directional long boreholes in roof fracture zones according to claim 1, characterized in that, The PLC, AD conversion module, DA conversion module, display screen, and remote transmission module in the pipeline control device are all intrinsically safe and housed in an intrinsically safe PLC control box.

5. The dynamic control device for efficient extraction from directional long boreholes in roof fracture zones according to claim 1, characterized in that, The number of boreholes in the same drilling site is not limited to three. If there are more than three, it is only necessary to increase the number of pipeline monitoring devices and the number of ports of AD conversion modules and DA conversion modules in the pipeline control device.

6. A method for dynamic control of efficient extraction from directional long boreholes in roof fracture zones, implemented based on the aforementioned dynamic control device for efficient extraction from directional long boreholes in roof fracture zones, characterized in that... The control method includes: Step 1: Construct a drilling site in the return air roadway of the underground working face. Construct directional long boreholes in the roof crack zone as required within the drilling site. After the boreholes are completed, seal them with cement mortar and connect them to the rubber connecting hose of the pipeline monitoring device through a flange. Step 2: Under the action of extraction negative pressure, the mixed gas in the borehole enters the seamless steel pipe through the rubber connecting hose. The negative pressure sensor monitors the negative pressure at the borehole opening in real time, the methane concentration sensor monitors the methane concentration in the extracted mixed gas in real time, and the differential pressure sensor monitors the pressure difference across the orifice plate of the orifice plate flow meter in real time. Step 3: The AD conversion module converts the analog data monitored in real time by various sensors into digital signals and transmits them to the PLC. The PLC displays the monitored data on the screen in real time. The PLC calculates the flow rate of the extracted mixed gas based on the orifice plate flow coefficient and the pressure difference across the orifice plate. Based on the methane concentration value monitored by the methane concentration sensor, the PLC calculates the pure amount of methane extracted from the extracted gas and displays it on the screen. At the same time, the PLC connects all the real-time monitored and calculated data to the mine ring network switch through the remote transmission module for data acquisition by the ground system. Step 4: Within a set time, the PLC controls the adjustable electric valve through the DA conversion module to adjust its opening degree from 0 degrees to 90 degrees, with an adjustment step of 1 degree. Each extraction borehole needs to be adjusted individually. During adjustment, other boreholes are in the closed state. For each degree adjustment of the adjustable electric valve, the PLC records the orifice extraction negative pressure, the flow rate of the extracted mixed gas, the methane concentration in the extracted mixed gas, and the pure gas extraction amount at the current valve opening degree. Step 5: Repeat step 4 to adjust the directional long borehole for each roof fracture zone, and record the valve opening degree and the corresponding extraction negative pressure, extraction gas mixed flow rate, and gas extraction purity at that opening degree. Step 6: For each directional long borehole in the roof fracture zone, the PLC compares the hole extraction negative pressure and gas extraction purity value corresponding to each angle during the adjustment process of the adjustable electric control valve from 0 to 90°, and determines the hole extraction negative pressure corresponding to the maximum gas extraction purity; this information is displayed on the screen and transmitted to the mine ring network switch through the remote transmission module. Step 7: The PLC adjusts the adjustable electric control valve through the DA conversion module to adjust the negative pressure of the extraction at the orifice of all the directional long boreholes in the roof crack zone to the negative pressure of the orifice corresponding to the maximum gas extraction volume of each borehole, so as to optimize the extraction efficiency under the current set time period. Step 8: When the next set time is reached, the PLC will repeat the process from Step 4 to Step 7 to optimize the extraction efficiency in the next time period.

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