An air jet punching operation device and method capable of realizing self-pressurization of mine pressure

Abstract

The present application belongs to the technical field of coal mine gas control and coal seam gas development, and particularly relates to an air jet piercing operation device and method capable of realizing self-pressurization of mine pressure air pressure, comprising a gas source pipeline and a water source pipeline, the gas source pipeline and the water source pipeline are connected through a gas tail inlet and a drill rod interior respectively, an air jet piercing device is connected to the front end of the drill rod, and a drill bit is connected to the front end of the air jet piercing device; the air jet piercing device is provided with an inner layer pipeline and an outer layer pipeline, the outer layer pipeline is provided with one self-pressurization assembly at the upper and lower symmetrical positions inside, each self-pressurization assembly comprises a micro screw air compressor and an air flow channel, a damping vortex fan and a Laval nozzle are arranged in the air flow channel, the damping vortex fan is arranged at the end of the driving shaft of the micro screw air compressor, the air inlet of the micro screw air compressor is connected with the inner layer pipeline through the air flow channel, and the air outlet of the micro screw air compressor is communicated with the outside through the air flow channel; two fixed blocks are arranged on the inner wall of the inner layer pipeline in a symmetrical manner, one spring is arranged on each fixed block, one sliding block is arranged at the end of the spring, and the sliding block blocks the air flow channel opening where the damping vortex fan is arranged and the air inlet of the micro screw air compressor when the spring is in a natural state, the device can realize self-pressurization of the air in the drill rod based on the micro screw air compressor arranged in the air jet piercing device, so that the breaking efficiency of the air jet on the coal body is improved.

Description

Technical Field

[0001] This invention belongs to the field of coal mine gas control and coalbed methane development technology, and particularly relates to an air jet punching device and operation method that can realize self-pressurization of mine air pressure. Background Technology

[0002] Currently, most coal mines in my country use hydraulic perforation technology to enhance coal seam permeability and improve gas extraction. However, problems such as uneven coal unloading and poor slag removal during hydraulic perforation can cause coal slag, water, and gas to accumulate in the borehole, leading to "blowout" and "stuck drill" phenomena. This results in excessive gas levels in the roadway and loss of drilling tools. Furthermore, after the coal body around the borehole is soaked in water, the fluidity of the coal body increases, making the structure of the perforation pressure relief space extremely unstable. This makes the borehole prone to collapse, difficult to install screen pipes, and prone to stress concentration zones.

[0003] To address various issues in hydraulic drilling technology, air jet drilling is employed for anhydrous pressure relief and permeability enhancement of coal seams. Air jet drilling creates a stable pressure relief space within the borehole, ensuring smooth slag removal during the drilling process and avoiding the "water lock effect," thus effectively improving drilling performance. Air pressure can affect coal output and drilling radius during air jet drilling operations; appropriately increasing the air pressure can effectively improve the efficiency of air jet drilling. Using the device and method proposed in this invention, self-pressurization of underground air pressure can be achieved. Summary of the Invention

[0004] The purpose of this invention is to provide an air jet punching device and method that enables self-pressurization of mine air pressure. Based on traditional punching equipment, this invention replaces hydraulic punching with air jet punching by adding an air jet puncher between the drill rod and the drill bit. This device utilizes a built-in micro-screw air compressor within the air jet puncher to achieve self-pressurization of the air inside the drill rod, thereby improving the efficiency of the air jet in crushing coal.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An air jet punching device capable of self-pressurizing air pressure in mines includes an air source pipeline and a water source pipeline, which are respectively connected to the drill rod via an air tail inlet. An air jet punch is connected to the front end of the drill rod, and a drill bit is connected to the front end of the air jet punch. The air jet punch has an inner pipeline and an outer pipeline. A self-pressurizing component is symmetrically positioned vertically within the outer pipeline. Each self-pressurizing component includes a miniature screw air compressor and an airflow channel. The flow channel is equipped with a damping turbofan and a Laval nozzle. The damping turbofan is located at the end of the drive shaft of the micro screw air compressor. The air inlet of the micro screw air compressor is connected to the inner pipeline through the air flow channel, and the exhaust port of the micro screw air compressor is connected to the outside through the air flow channel. Two fixing blocks are symmetrically arranged on the upper and lower sides of the inner wall of the inner pipeline. Each fixing block is equipped with a spring, and a slider is provided at the end of the spring. When the spring is in its natural state, the slider blocks the air flow channel opening where the damping turbofan is located and the air inlet of the micro screw air compressor.

[0007] Furthermore, the airflow channels include airflow channel one, airflow channel two, airflow channel three, and airflow channel four. Airflow channel one is connected to the air inlet of the micro screw air compressor. The damping turbo fan is located inside airflow channel four. Airflow channels one and four are connected to the inner pipeline when the spring is in the compressed state. Each slider blocks airflow channels one and four when the spring is in the uncompressed state. Airflow channel three is connected to the exhaust port of the micro screw air compressor and has a Laval nozzle at its end that is connected to the outside. Airflow channel two is connected to the exhaust port of the damping turbo fan and its other end is connected to the outside.

[0008] Furthermore, it also includes a small steel ball, the outer diameter of which matches the inner diameter of the drill rod, and the inner diameter of the drill rod is connected to and has the same diameter as the internal pipeline of the air jet punch.

[0009] Furthermore, the slider inside the air jet punch is a hollow cylinder, and its outer diameter matches the inner pipeline of the air jet punch. A gap is provided between the two fixed blocks.

[0010] Furthermore, the outer pipeline is also equipped with an air volume adjustment channel, which is connected to the airflow channel and has a sealing bolt inside.

[0011] Furthermore, the micro screw air compressor is provided with a sealed housing on the outside, and a driving screw and a driven screw that mesh with each other are provided inside the sealed housing. The driving screw is sleeved on the drive shaft, and the driven screw is movably disposed inside the sealed housing. Both the driving screw and the driven screw are provided with meshing tooth grooves on the outside.

[0012] Furthermore, the drill rod and the air jet punch are respectively provided with internal and external threads at both ends, the drill bit is provided with internal pipelines, and the drill bit surface is provided with nozzles; the air source pipeline includes an air pressure pump, an air storage tank connected to the air pressure pump, a valve and a pressure gauge on the outlet pipeline of the air storage tank, and the gas outlet pipeline is connected to the air tail inlet; the water source pipeline includes a water tank, a high-pressure water pump connected to the outlet of the water tank, the outlet pipeline of the high-pressure water pump is connected to the air tail inlet, and a valve and a pressure gauge are also provided on the outlet pipeline of the water tank.

[0013] A method for air jet punching operation with self-pressurized air pressure in mines includes the following steps:

[0014] S1. Add water to the water tank, connect the high-pressure water pump to the air tail inlet using a high-pressure hose, connect the air tail to the internal passage of the drill rod, and install the air jet punch between the drill bit and the drill rod. Turn on the high-pressure water pump and the directional drilling machine, set the water pressure to 0.5MPa for drilling. The water flows through the internal passage of the drill rod and the middle passage of the inner tube slider of the air jet punch, and finally the water flows into the inside of the drill bit and is sprayed out through the drill bit nozzle to cool down and reduce dust.

[0015] S2. After drilling is completed, turn off the directional drilling machine and the high-pressure water pump, disconnect the high-pressure water pump and the air tail, and let the water remaining in the drill rod and the inner pipeline of the air jet punch flow out.

[0016] S3. After water stops flowing out, place the steel ball into the air tail inlet. Connect the air pump to the air tail inlet using a high-pressure hose and turn on the air pump. When the gas pressure in the storage tank reaches 5MPa, open the valve to introduce high-pressure air into the inner drill rod. Control the air release pressure to 1MPa using a pressure gauge. The high-pressure gas communicates with the inside of the drill rod from the air tail inlet. The high-pressure gas reaches the inner pipeline of the air jet punch through the internal passage of the drill rod, carrying the steel ball to the inner pipeline of the air jet punch. When the steel ball touches the slider of the inner pipeline, the spring contracts, causing the steel ball to move forward. After the slider moves, the gas interacts with the outer pipeline. The airflow channels 1 and 4 are connected. A portion of the gas passes through airflow channel 4, which drives the damping turbofan to rotate. The damping turbofan drives the drive shaft to rotate, which makes the micro screw air compressor work. The gas after passing through the damping turbofan is discharged to the outside of the air jet punch through airflow channel 2 and used for slag removal. Another portion of the gas passes through airflow channel 1 to the air inlet of the micro screw air compressor, which makes the screw air compressor work. The gas enters the sealed space formed between the tooth groove and the sealing shell, where it is compressed. The compressed gas is discharged from the exhaust port of the micro screw air compressor and finally reaches the Laval nozzle through airflow channel 3, where it is accelerated and ejected.

[0017] S4. The directional drilling rig drives the drill rod and the air jet punch to rotate and gradually withdraw from the borehole. The self-pressurized air jet is ejected from the air jet punch to break the coal body, thereby performing the punching operation.

[0018] S5. After the punching operation is completed, turn off the air pump. The steel ball slides out of the drill rod, removing the drill rod, air jet punch and drill bit. At this time, the slider moves backward under the action of the spring, blocking the airflow channel one and airflow channel four in the outer pipeline again.

[0019] S6. Adjust the angle of the directional drilling rig, and repeat steps S1-S5 at the new drilling location to perform punching operations at the new drilling location.

[0020] The advantages of this invention are:

[0021] 1. This invention uses air jets instead of traditional hydraulic punching, which can create a relatively stable pressure relief space in the borehole during punching, thereby avoiding borehole collapse and improving punching efficiency. In addition, the use of waterless punching can avoid water lock effect, thereby improving gas extraction efficiency after punching.

[0022] 2. This invention can achieve self-pressurization of underground air pressure, thereby improving the efficiency of air jet coal breaking, which is more economical than the traditional method;

[0023] 3. This invention enables integrated drilling and punching operations on coal seams. Punching can be performed without retracting the drill after drilling, thus improving operational efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall punching device of the present invention.

[0025] Figure 2 This is a schematic diagram of the air jet punch in this invention.

[0026] Figure 3 This is a schematic diagram of the micro screw air compressor structure inside the air jet punch of the present invention.

[0027] Figure 4 This is a schematic diagram of the drill pipe structure in this invention.

[0028] Figure 5 This is a schematic diagram of the sealing bolt in this invention. Detailed Implementation

[0029] Example

[0030] like Figure 1-5As shown, an air jet drilling device capable of self-pressurizing underground air pressure includes an air jet punch 10, a drill bit 11, a directional drilling rig 9, a drill rod 8, an air tail 5, an air pump 1, a high-pressure gas storage tank 2, a valve 3, a pressure gauge 4, a water tank 6, and a high-pressure water pump 7. The drill rod 8 has an internal thread 29 at one end and an external thread 30 at the other. Multiple drill rods can be connected as needed. The air jet punch is threadedly mounted on the front end of the drill rod, and the drill bit 11 is threadedly mounted on the front end of the air jet punch. The drill bit has internal piping for water circulation, and a nozzle at the front end of the drill bit is used to spray water for cooling and dust suppression during drilling.

[0031] The air jet punch 10 mainly includes an inner pipeline and an outer pipeline. The inner pipeline is connected to the internal passage of the drill rod and has the same diameter. The outer pipeline contains a miniature screw air compressor 17, a miniature screw air compressor drive shaft 22, a damping turbo fan 23, a Laval nozzle 20, and air volume adjustment channels 12, airflow channels one 14, airflow channel two 15, airflow channel three 19, and airflow channel four 21. Airflow channel one 14 is connected to the screw air compressor inlet 16. Before operation, the area of ​​airflow channel one can be adjusted through an internal pipe according to different operating conditions, thereby adjusting the air intake of the screw air compressor. After adjustment, the air volume adjustment channel is blocked with sealing bolts 13. The damping turbo fan 23 and the miniature screw air compressor drive shaft 22 are located in airflow channel four 21. The damping turbo fan is installed at the end of the miniature screw air compressor drive shaft. When the vortex fan rotates, it can drive the drive shaft of the micro screw air compressor to rotate, thereby starting the micro screw air compressor 17 to work. The Laval nozzle 20 is connected to the exhaust port 18 of the screw air compressor through the airflow channel 3 19 and communicates with the outside. Except for the micro screw air compressor and each channel, the rest of the outer pipeline is solid. The inner pipeline has two fixed blocks 26 symmetrically arranged on the upper and lower walls. Each fixed block is equipped with a spring 25. The end of the spring is equipped with a slider 24. The middle of the two sliders is a central passage. The slider is a hollow cylinder, and its outer diameter matches the inner pipeline of the air jet punch. The outside of the two sliders are the airflow channel 14 and airflow channel 4 21 of the outer pipeline. When the spring is in its natural state, the slider can block the airflow channel 14 and airflow channel 4 21. When the slider moves, the spring deforms, which allows the inner pipeline to communicate with the external airflow channel 14 and airflow channel 4 21.

[0032] During drilling operations, the high-pressure water pump 7 is connected to the drill rod 8 through the air tail inlet 5. The high-pressure water flows through the air jet punch 10 through the internal passage of the drill rod. At this time, the water pressure is relatively low and will not cause the slider 24 to move. The water finally reaches the inside of the drill bit 11 through the middle passage of the inner layer pipeline of the air jet punch. The water is sprayed out from the nozzle at the front end of the drill bit to cool down and reduce dust during drilling.

[0033] During the punching operation, a small steel ball is placed into the air tail inlet 5. The air pressure pump 1 is connected to the drill rod 8 through the air tail inlet. The high-pressure gas carries the steel ball to the inner pipeline of the air jet punch 10. When the steel ball touches the slider 24 in the inner pipeline, the spring 25 contracts, and the steel ball drives the slider to move backward and approach the fixed block 26. After the slider moves, the high-pressure gas communicates with the airflow channel 14 and airflow channel 21 in the outer pipeline. The gas passes through airflow channel 21, which drives the damping turbo fan 23 to rotate. The damping turbo fan drives the drive shaft 22 of the micro screw air compressor to rotate, thereby enabling the micro screw air compressor 17 to work. The gas that has passed through the damping turbo fan can then pass through the airflow channel 21. The gas is discharged from the outside of the air jet punch through the second channel 15, directly into the borehole and used for slag removal; the gas reaches the screw air compressor inlet 16 through the airflow channel 14, the screw air compressor inlet opens, and the gas enters the screw air compressor. At this time, the high-pressure air in the inner pipeline makes the screw air compressor work. The gas enters the sealed space formed between the screw tooth groove and the screw air compressor sealing shell 27. As the screw 28 rotates, the volume of the sealed space formed between the screw tooth groove and the screw air compressor sealing shell gradually decreases, thereby compressing the gas inside. The compressed gas is discharged from the screw air compressor exhaust port 18 and finally reaches the Laval nozzle 20 with the airflow channel, where it is accelerated and ejected.

[0034] Material balance calculations related to the drill pipe internal screw air compressor:

[0035] Gas flow rate after entering the drill pipe:

[0036] Q = v × πr 2 In the formula, Q is the gas flow rate; r is the radius of the internal passage of the drill pipe, which is 2 cm; and v is the gas velocity, which is 8 m / s.

[0037] The gas flow rate entering the inlet of the screw air compressor is:

[0038]

[0039] In the formula, Q2 is the gas flow rate entering a screw air compressor; A1 is the cross-sectional area of ​​the airflow passage after adjustment via the internal insertion pipe; A2 is the cross-sectional area of ​​the airflow passage, which is 3.14 cm². 2 .

[0040] Adjust the airflow channel to have a cross-sectional area of ​​0.0314 cm². 2 Therefore, Q2 can be calculated to be 0.0029m. 3 / min. The intake flow rate of a normal screw air compressor, approximately 10 times the size of the micro screw air compressor described in this invention, is about 2.5m³ / min. 3Its volume is approximately 1000 times that of the miniature screw air compressor. Proportionally, if the volume of the screw air compressor were reduced by 1000 times, its intake flow rate would be 0.0025 m³ / min. 3 / min, Q2 is 0.0029m 3 The difference between the two is small. Furthermore, adjusting the cross-sectional area of ​​the airflow channel to decrease Q2 increases the intake flow rate of airflow channel four, allowing the screw air compressor to rotate faster. Increased rotation speed allows the screw air compressor to withstand a higher intake flow rate, thus Q2 meets the screw air compressor's pressurization requirements. In actual operation, due to limitations such as leakage, suction resistance, and rotation speed, the intake flow rate cannot increase proportionally when the screw air compressor's volume increases. Therefore, the intake flow rate that the micro screw air compressor in this invention can withstand is far greater than 0.0025 m³ / min. 3 / min, so the airflow channel area can be adjusted according to different working conditions to flexibly adjust the intake flow of the screw air compressor.

[0041] The compression process inside a screw air compressor is very rapid, and it is close to an adiabatic compression process. Therefore, the gas pressure at the exhaust port of the screw air compressor can be calculated using the following formula:

[0042]

[0043] In the formula, P1 is the gas pressure at the inlet of the screw air compressor; P2 is the gas pressure at the outlet of the screw air compressor; V1 is the inlet volume of the screw air compressor; V2 is the outlet volume of the screw air compressor; k is the air adiabatic index, which is taken as 1.4.

[0044] The compression ratio of a screw air compressor is not directly related to the size of the screw air compressor. It mainly depends on the screw pitch and tooth profile design, etc. When V1 / V2 is 3:1 and P1 is 1MPa, P2 can be calculated to be 4.66MPa.

[0045] The formula for calculating the gas velocity after acceleration by the Laval nozzle is as follows:

[0046]

[0047] In the formula, P e P0 is the gas pressure at the outlet of the Laval nozzle; P0 is the gas pressure at the inlet of the Laval nozzle, P0 = P2; Ma is the Mach number at the outlet of the Laval nozzle.

[0048] P0 is 4.66 MPa. When the expansion ratio of the Laval nozzle is constant, the gas outlet pressure is also constant. If a Laval nozzle with an expansion ratio of 1.12 is used, then P... eIf the pressure is 0.113484 MPa, then Ma can be calculated to be 2.24. Using the device and method of this invention, air can be accelerated to a super-high-speed air jet exceeding Mach 2, which can effectively disrupt the coal seam, thereby enabling air jet perforation operations.

[0049] The relevant calculations for the slider in the inner layer of the air jet punch are as follows:

[0050] Ignoring frictional losses and other factors, calculate the gas pressure during punching:

[0051]

[0052] In the formula, P3 is the gas pressure that allows the slider to move during punching; r2 is the radius of the steel ball, which is 2cm; m1 is the mass of the steel ball, which is 270g; m2 is the mass of the slider, which is 200g; k2 is the spring constant, which is 12500N / m; and x is the spring contraction distance.

[0053] When the spring contracts by 4.5cm, the gas in the inner pipeline can completely enter the airflow channels one and four. When x is 4.5cm, P3 can be calculated to be 0.9MPa. That is, when the gas pressure is greater than 0.9MPa during punching, the gas in the inner pipeline can completely enter the airflow channels one and four.

[0054] Calculate the water pressure during drilling:

[0055]

[0056] In the formula, P4 is the water pressure during drilling; A3 is the side area of ​​the water flow impacting the slider, which is 3.14 cm². 2 .

[0057] When the spring contracts to less than 1.4cm, the airflow channel four is still blocked by the slider. When x is 1.4cm, P4 can be calculated to be 0.56MPa. That is, when the water pressure is less than 0.56MPa during drilling, the airflow channel one and the airflow channel four are still blocked by the slider, and the water flow in the inner pipeline cannot enter.

Claims

1. An air jet punching device capable of self-pressurizing underground air pressure, comprising an air source pipeline and a water source pipeline, wherein the air source pipeline and the water source pipeline are respectively connected through an air tail inlet and the inside of a drill rod, wherein an air jet puncher is connected to the front end of the drill rod, and a drill bit is connected to the front end of the air jet puncher; characterized in that: The air jet punch has an inner layer pipeline and an outer layer pipeline. A self-pressurizing component is symmetrically positioned vertically within the outer layer pipeline. Each self-pressurizing component includes a miniature screw air compressor and an airflow channel. The airflow channel contains a damping turbofan and a Laval nozzle. The damping turbofan is located at the end of the drive shaft of the miniature screw air compressor. The air inlet of the miniature screw air compressor is connected to the inner layer pipeline through the airflow channel, and the exhaust port of the miniature screw air compressor is connected to the outside through the airflow channel. Two fixing blocks are symmetrically positioned vertically on the inner wall of the inner layer pipeline. Each fixing block has a spring, and a slider is located at the end of the spring. When the spring is in its natural state, the slider blocks… The damping turbofan is located in the airflow channel and the air inlet of the micro screw air compressor. The airflow channel includes airflow channel one, airflow channel two, airflow channel three and airflow channel four. Airflow channel one is connected to the air inlet of the micro screw air compressor. The damping turbofan is located in airflow channel four. Airflow channels one and four are connected to the inner pipeline when the spring is in the compressed state. Each slider blocks airflow channels one and four when the spring is in the uncompressed state. Airflow channel three is connected to the exhaust port of the micro screw air compressor and has a Laval nozzle at its end that is connected to the outside. Airflow channel two is connected to the exhaust port of the damping turbofan and its other end is connected to the outside.

2. The air jet punching device for achieving self-pressurization of underground air pressure as described in claim 1, characterized in that: It also includes a steel ball, the outer diameter of which matches the inner diameter of the drill rod, and the inner diameter of the drill rod is connected to and has the same diameter as the internal pipeline of the air jet punch.

3. The air jet punching device for achieving self-pressurization of underground air pressure as described in claim 1, characterized in that: The slider inside the air jet punch is a hollow cylinder, and its outer diameter matches the inner pipeline of the air jet punch. There is a gap between the two fixed blocks.

4. The air jet punching device for achieving self-pressurization of underground air pressure as described in claim 1, characterized in that: The outer pipeline is also equipped with a gas volume adjustment channel, which is connected to the airflow channel and has a sealing bolt inside.

5. The air jet punching device for realizing self-pressurization of underground air pressure as described in claim 2, characterized in that: The micro screw air compressor is equipped with a sealed housing on the outside. Inside the sealed housing are a driving screw and a driven screw that mesh with each other. The driving screw is sleeved on the drive shaft, and the driven screw is movably disposed inside the sealed housing. Both the driving screw and the driven screw are provided with meshing tooth grooves on the outside.

6. The air jet punching device for achieving self-pressurization of underground air pressure as described in claim 5, characterized in that: The drill rod and the air jet punch are respectively provided with internal and external threads at both ends. The drill bit has an internal pipeline and a nozzle on its surface. The air source pipeline includes an air pressure pump and an air storage tank connected to the air pressure pump. The outlet pipeline of the air storage tank is equipped with a valve and a pressure gauge. The gas outlet pipeline is connected to the air tail inlet. The water source pipeline includes a water tank and a high-pressure water pump connected to the outlet of the water tank. The outlet pipeline of the high-pressure water pump is connected to the air tail inlet. The outlet pipeline of the water tank is also equipped with a valve and a pressure gauge.

7. The method for mine underground air jet punching operation using the device described in claim 6, comprising the following steps: S1. Add water to the water tank, connect the high-pressure water pump to the air tail inlet using a high-pressure hose, connect the air tail to the internal passage of the drill rod, and install the air jet punch between the drill bit and the drill rod. Turn on the high-pressure water pump and the directional drilling machine, set the water pressure to 0.5MPa for drilling. The water flows through the internal passage of the drill rod and the middle passage of the inner tube slider of the air jet punch, and finally the water flows into the inside of the drill bit and is sprayed out through the drill bit nozzle to cool down and reduce dust. S2. After drilling is completed, turn off the directional drilling machine and the high-pressure water pump, disconnect the high-pressure water pump and the air tail, and let the water remaining in the drill rod and the inner pipeline of the air jet punch flow out. S3. Once water flow ceases, place the steel ball into the air tail inlet. Connect the air pump to the air tail inlet using a high-pressure hose. Turn on the air pump. When the gas pressure in the storage tank reaches 5 MPa, open the valve to introduce high-pressure air into the inner drill rod. Control the air release pressure to 1 MPa using a pressure gauge. The high-pressure gas communicates with the inside of the drill rod from the air tail inlet. The high-pressure gas reaches the inner pipeline of the air jet punch through the internal passage of the drill rod, carrying the steel ball to the inner pipeline of the air jet punch. When the steel ball touches the slider in the inner pipeline, the spring contracts, causing the steel ball to move forward. After the slider moves, the gas flows through the airflow channel in the outer pipeline. One airflow channel is connected to the fourth airflow channel. Part of the gas passes through the fourth airflow channel to drive the damping turbofan to rotate. The damping turbofan drives the drive shaft to rotate, which makes the micro screw air compressor work. The gas after passing through the damping turbofan passes through the second airflow channel to the outside of the air jet punch and is used for slag removal. Another part of the gas passes through the first airflow channel to the air inlet of the micro screw air compressor, which makes the screw air compressor work. The gas enters the sealed space formed between the tooth groove and the sealing shell, where the gas is compressed. The compressed gas is discharged from the exhaust port of the micro screw air compressor and finally reaches the Laval nozzle with the third airflow channel, where it is accelerated and ejected. S4. The directional drilling rig drives the drill rod and the air jet punch to rotate and gradually withdraw from the borehole. The self-pressurized air jet is ejected from the air jet punch to break the coal body, thereby performing the punching operation. S5. After the punching operation is completed, turn off the air pump. The steel ball slides out of the drill rod, removing the drill rod, air jet punch and drill bit. At this time, the slider moves backward under the action of the spring, blocking the airflow channel one and airflow channel four in the outer pipeline again. S6. Adjust the angle of the directional drilling rig, and repeat steps S1-S5 at the new drilling location to perform punching operations at the new drilling location.

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