Gas extraction drill hole collapse dredging and supporting drilling device and method

Abstract

The invention belongs to the technical field of coal mine gas extraction safety, and particularly relates to a gas extraction drill hole collapse hole dredging and supporting drilling device and method. Comprising a coal breaking dredging part and a supporting pipe pushing part, the coal breaking dredging part comprises a coal breaking drill bit, an outer pipe and an inner pipe which are all of a hollow structure. The supporting pipe pushing part comprises a supporting pipe, a threaded spiral pipe and a micro motor; coal in a collapsed hole is smashed and discharged through the coal breaking and dredging part, and a supporting pipe body is pushed into a dredged drill hole through the supporting pipe pushing part; according to the method, the blocked gas extraction drill hole is dredged and supported, the gas extraction space is greatly recovered, and the gas extraction flow is increased; the problem that the gas extraction flow is reduced due to hole collapse of the drill hole is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mine gas extraction safety, and specifically relates to a gas extraction borehole collapse dredging and support drilling device and method. Background Art

[0002] Coal mine gas disasters seriously restrict the safe and efficient production of mines. As the main measure to control coal mine gas disasters, gas extraction is closely related to the safe production of mines. However, due to the complex geological structure and coal seam storage conditions of my country's coal mines, more than 50% of the mines currently mined are high-gas or coal and gas outburst mines. The gas extraction rate of these mines is low and is affected by many factors, including coal seam permeability, system grid connection, sealing quality and borehole blockage. Borehole blockage is one of the important reasons. Because of the influence of the circumferential stress and the change of negative pressure during the drilling and extraction process, the coal body of the hole wall will be displaced, causing the extraction borehole to deform or even block, thereby blocking the channel for gas flow in the borehole, and finally causing the extraction efficiency of the extraction borehole to decrease, the extraction time to reach the standard to be extended, and the mining and extraction of high-gas and outburst mines to be unbalanced, and at the same time leaving safety hazards to mining and production. Therefore, it is very necessary to quickly remove the coal slag blocked in the borehole to improve the efficiency of mine gas extraction.

[0003] In order to solve the above problems, it is necessary to further develop a rapid dredging device suitable for gas extraction boreholes in coal mines. The device can quickly remove the coal slag that blocks the borehole, thereby improving the gas extraction efficiency of the mine. At present, in order to solve the technical problem of the actual average gas extraction rate due to coal slag blockage in high-gas mines and coal and gas outburst mines, China CN215408545U discloses a water-driven borehole collapse repair and hole protection device, and CN112963111A discloses a gas extraction borehole hydraulic drive automatic dredging device and other patents. The repair equipment has a simple structure, but the above process repair operation procedures are relatively cumbersome, and the integration of borehole dredging and hole protection has not been realized. The time for repairing the collapsed hole is long, and it is impossible to quickly reduce the gas content of the coal seam, thereby affecting the safety production of coal mines underground, and it is difficult to quickly recover the losses.

[0004] Therefore, it is of great significance to develop an integrated device for clearing and protecting collapsed boreholes for gas extraction in underground coal mines. Summary of the invention

[0005] The present invention overcomes the shortcomings of the prior art and proposes a gas extraction borehole collapse dredging and support drilling device and method; solves the problem of reduced gas extraction flow caused by borehole collapse; the present invention is achieved through the following technical solutions: A gas extraction borehole collapse dredging and support drilling device, comprising a coal breaking dredging part and a support pipe pushing part; the coal breaking dredging part comprises a coal breaking drill bit, an outer tube and an inner tube, all of which are hollow structures; the inner tube is fixedly arranged inside the outer tube; a first high-pressure flexible hose is connected to the rear end of the inner tube; and a second high-pressure flexible hose is connected to the rear end of the outer tube; The coal-breaking drill bit is rotatably connected to the inner tube through a first bearing, and the front end of the coal-breaking drill bit extends to the outside of the outer tube to form an enlarged drill bit part; the outer edge of the drill bit part is provided with a drill bit outer wall thread, and the front end of the coal-breaking drill bit is provided with a front nozzle; a first turbine is provided on the wall of the first cavity inside the coal-breaking drill bit; a recoil hole is formed between the coal-breaking drill bit and the front end of the outer tube; a spiral hole expansion and slag discharge pipe is rotatably connected to the outer tube, and both ends of the threaded hole expansion and slag discharge pipe are respectively connected to the tube wall of the outer tube through a second bearing, so that the threaded hole expansion and slag discharge pipe can rotate on the outer tube; and the threaded hole expansion and slag discharge pipe is located on the outside of the side wall of the coal-breaking drill bit; a spiral protrusion is provided on the side of the threaded hole expansion and slag discharge pipe located outside the outer tube, and a second turbine is provided on the side of the threaded hole expansion and slag discharge pipe located inside the outer tube; The support pipe pushing part includes a support pipe, a threaded spiral pipe and a micro motor; the front end of the support pipe is connected to the rear end of the outer pipe; two threaded spiral pipes are symmetrically installed on the pipe wall of the support pipe; the two ends of the threaded spiral pipe are rotatably connected to the pipe wall of the support pipe through bearings, and the threaded spiral pipe is fixedly connected to the driving shaft of the micro motor; the inner wall of the spiral spring support pipe is threadedly connected to the outer wall of the threaded spiral pipe; the outer wall thread of the drill bit, the spiral protrusion and the external thread of the threaded spiral pipe are all located on the same circumferential surface, which is used to enable the spiral spring support pipe to be pushed into the drill hole along the support pipe, the outer pipe and the coal breaking drill bit.

[0006] Furthermore, the coal breaking drill bit, outer tube and inner tube are all coaxially arranged.

[0007] Furthermore, the outer wall of the inner tube and the inner wall of the outer tube are cross-connected via a connecting rod; the connecting rod is made of a rectangular metal block.

[0008] Furthermore, irregular crushing protrusions are arranged on the end face of the front end of the coal breaking drill bit.

[0009] Furthermore, the rear end of the support pipe is used to be connected to the outer wall of the subsequent pipeline through a threaded structure.

[0010] Furthermore, the micro motor is wrapped with a steel half cylinder.

[0011] A gas extraction borehole collapse dredging and support drilling method is based on the gas extraction borehole collapse dredging and support drilling device, and includes the following steps: S1, high-pressure water flow a enters the first cavity through the first high-pressure flexible hose, and interacts with the first turbine in the coal-breaking drill bit in the first cavity to drive the coal-breaking drill bit to rotate and break the coal blocks and clear the blocked collapsed hole with the high-pressure water flow a ejected from the front nozzle; at the same time, high-pressure water flow b enters the second cavity between the outer tube and the inner tube, and interacts with the second turbine in the spiral hole expansion and slag discharge pipe to drive the spiral hole expansion and slag discharge pipe to rotate, and the high-pressure water flow b is ejected from the recoil hole in the reverse direction and acts together with the rotating spiral protrusion 401 to push the coal slag, and the broken coal slag is discharged along the drill hole; S2. After the dredging is completed, the borehole support is carried out: first, the high-pressure water flow a is replaced by high-pressure gas to drain the water in the first cavity and the first high-pressure flexible hose, and then the high-pressure water flow b is replaced by high-pressure liquid nitrogen, so that the high-pressure liquid nitrogen enters the second cavity through the second high-pressure flexible hose, and then sprays out from the recoil hole to temporarily freeze and fix the support area; then a micro motor is used to drive the threaded spiral tube to rotate and push the spiral spring support tube to the front end of the coal-breaking drill bit, so that the spiral spring support tube is sent out through the spiral protrusion and the thread of the outer wall of the drill bit to support the collapsed hole of the gas extraction borehole.

[0012] The beneficial effects of the present invention compared with the prior art are as follows: The present invention aims at the problem of sudden drop in gas extraction volume caused by gas extraction boreholes that have collapsed in coal mines. By combining a hydraulic combined mechanical drill bit and a spiral spring support pipe, the blocked gas extraction borehole is unblocked and supported, which greatly restores the space for gas extraction, unblocks the channel for gas flow, and increases the flow rate of gas extraction. The method has a simple and convenient operation process, has an efficiency advantage over traditional collapsed hole unblocking methods, and has wide practicability.

[0013] The device of the present invention is stable, safe and reliable through water drive, easy to operate and efficient. Through the application of the device, the coal slag blocked by the borehole can be quickly removed, thereby improving the efficiency of mine gas extraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall cross-sectional structure of the present invention; Figure 2 It is a structural diagram of the coal breaking and dredging part; Figure 3 is a schematic diagram of the connection between the coal breaking and dredging part and the first and second high-pressure flexible hoses; Figure 4 is a schematic diagram of the position structure of the first and second high-pressure flexible hoses; Figure 5 It is a structural schematic diagram of the support and push pipe part; Figure 6 It is a schematic diagram of the connection structure of the outer tube and the inner tube.

[0015] In the figure: 1-front nozzle, 2-coal breaking drill bit, 201-first turbine, 202-irregular crushing protrusion, 203-drill bit outer wall thread, 3-recoil hole, 4-spiral expansion slag discharge pipe, 401-spiral protrusion, 402-second turbine, 5-second bearing, 6-first bearing, 7-outer tube, 8-connecting rod, 9-inner tube, 10-threaded spiral tube, 11-micro motor, 12-steel half cylinder, 13-flexible wire, 14-subsequent pipeline, 15-second high-pressure flexible hose, 16-first high-pressure flexible hose, 17-first cavity, 18-second cavity, 19-support tube. DETAILED DESCRIPTION

[0016] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail in conjunction with the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The technical solutions of the present invention are described in detail below in conjunction with the embodiments and the accompanying drawings, but the scope of protection is not limited thereto.

[0017] See also Figures 1 to 6 , This embodiment proposes a gas extraction borehole collapse dredging and support drilling device, including a coal breaking dredging part and a support pipe pushing part; The coal breaking and dredging part includes a coal breaking drill bit 2, an outer tube 7 and an inner tube 9, all of which are hollow structures; the coal breaking drill bit 2, the outer tube 7 and the inner tube 9 are coaxially arranged; the inner tube 9 is located inside the outer tube 7, and the outer wall of the inner tube 9 is cross-connected with the inner wall of the outer tube 7 by a connecting rod 8, and the connecting rod 8 is made of a rectangular metal block. A first high-pressure flexible hose 16 is threadedly connected to the rear end of the inner tube 9; a second high-pressure flexible hose 15 is threadedly connected to the rear end of the outer tube 7.

[0018] The rear end of the coal-breaking drill bit 2 is rotatably connected to the front end of the inner tube 9 through the first bearing 6, so that the coal-breaking drill bit 2 can rotate around its axis, and the front end of the coal-breaking drill bit 2 extends to the outside of the outer tube 7 to form an enlarged drill bit part; the outer edge of the drill bit part is provided with a drill bit outer wall thread 203, which is convenient for breaking the coal in the collapsed hole during the drilling process; the front end of the coal-breaking drill bit 2 is provided with a front nozzle 1 for spraying a high-pressure water flow a into the borehole; a first turbine is provided on the wall of the first cavity 17 inside the coal-breaking drill bit 2 201; when the high-pressure water flow a delivered by the first high-pressure flexible hose 16 enters the first cavity 17, it will interact with the first turbine 201 in the coal-breaking drill bit 2 in the first cavity 17 to drive the coal-breaking drill bit 2 to rotate at high speed; an irregular crushing protrusion 202 is arranged on the end face of the front end of the coal-breaking drill bit 2. When the coal-breaking drill bit 2 rotates at high speed, the irregular crushing protrusion 202 at the front end of the coal-breaking drill bit 2 and the high-pressure water flow a sprayed from the front nozzle 1 are used to crush the coal blocks blocked in the collapsed hole and clear the drill hole at the same time.

[0019] A recoil hole 3 is formed between the coal-breaking drill bit 2 and the front end of the outer tube 7; one section of the outer tube 7 is a rotatable structure, and the rotatable structure is Figure 1 The spiral expansion slag discharge pipe 4 in the embodiment; both ends of the threaded expansion slag discharge pipe 4 are connected to the pipe wall of the outer pipe 7 through the second bearing 5 respectively, so that the threaded expansion slag discharge pipe 4 can rotate on the outer pipe 7; a spiral protrusion 401 is provided on the side of the threaded expansion slag discharge pipe 4 located outside the outer pipe 7, and a second turbine 402 is provided on the side of the threaded expansion slag discharge pipe 4 located inside the outer pipe 7; the threaded expansion slag discharge pipe 4 is located outside the side wall of the coal breaking drill bit 2; when the high-pressure water flow b delivered by the second high-pressure flexible hose 15 enters the second cavity 18 formed between the inner pipe 9 and the outer pipe 7, the high-pressure water flow b interacts with the second turbine 402 on the spiral expansion slag discharge pipe 4 to drive the spiral expansion slag discharge pipe 4 to rotate, and at the same time, the recoil water flow ejected from the recoil hole 3 and the spiral protrusion 401 outside the spiral expansion slag discharge pipe 4 rotate together to push the broken coal slag to be discharged along the drill hole.

[0020] The support and push pipe part includes a support pipe 19; the front end of the support pipe 19 is threadedly connected to the rear end of the outer pipe 7; the rear end of the support pipe 19 is used to connect to the outer wall of the subsequent pipeline 14 through a threaded structure. Two threaded spiral pipes 10 are symmetrically installed on the pipe wall of the support pipe 19; the two ends of the threaded spiral pipe 10 are rotatably connected to the pipe wall of the support pipe 19 through bearings, so that the threaded spiral pipe 10 can rotate along the pipe wall of the support pipe 19, and the threaded spiral pipe 10 is fixedly connected to the driving shaft of the micro motor 11, and the threaded spiral pipe 10 is driven to rotate by the micro motor 11; the entire micro motor 11 is wrapped by a steel half cylinder 12 to prevent the front end spiral shaft of the micro motor 11 from scratching the second high-pressure flexible hose 15, and the micro motor 11 is powered by a flexible wire 13 connected to the rear end. The coil spring support tube is an existing component used to support drilling. The inner wall of the coil spring support tube is threadedly connected to the outer wall of the threaded spiral tube 10; the outer wall thread 203 of the drill bit, the spiral protrusion 401 and the external thread of the threaded spiral tube 10 are all located on the same circumferential surface, which is used to enable the coil spring support tube to be pushed into the drill hole along the support tube 19, the outer tube 7 and the coal breaking drill bit 2.

[0021] In the initial period, the front end of the rigid spiral spring support pipe (whose properties hardly change at low temperatures) is stuck in the concave part of the spiral of the outer wall of the threaded spiral pipe 10 and is fixed, and drills along with the coal-breaking drill bit 2 as a whole; when support is needed after the drilling hole is dredged, the high-pressure water flow a is first replaced with high-pressure gas to drain the water in the first cavity 17 and the first high-pressure flexible hose 16, and then the high-pressure water flow b is replaced with high-pressure liquid nitrogen, so that the high-pressure liquid nitrogen enters the second cavity 18 through the second high-pressure flexible hose 15, and then is sprayed out from the recoil hole 3 to temporarily freeze and fix the part that needs support; then the micro motor 11 is used to drive the threaded spiral pipe 10 to rotate and push the spiral spring support pipe toward the front end of the coal-breaking drill bit 2, so that the spiral spring support pipe is sent out through the spiral protrusion 401 of the spiral hole expansion and slag discharge pipe 4 and the outer wall thread 203 of the drill bit to support the collapsed part of the gas extraction borehole. After the coal seam gas extraction drilling hole collapse dredging and support are completed, the micro motor 11 is controlled to drive the threaded spiral pipe 10 to rotate in the reverse direction to withdraw the drill bit from the spiral spring support pipe.

[0022] The working process of a gas extraction borehole collapse dredging and support drilling device described in this embodiment is as follows: According to the actual working conditions of the mine, the coal breaking and dredging part and the supporting and pushing pipe part of the support drilling device are installed and fixed, and the two are connected by a spiral. The coal breaking and dredging part uses a high-pressure water pump to deliver high-pressure water flow a through the first high-pressure flexible hose 16 into the first cavity 17, and interacts with the first turbine 201 in the coal breaking drill bit 2 in the first cavity 17 to drive the coal breaking drill bit 2 to rotate at high speed, and utilizes the irregular crushing protrusion 202 at the front end of the coal breaking drill bit 2 and the high-pressure water flow a sprayed from the front nozzle 1 to crush coal blocks and dredge the blocked collapsed hole; at the same time, the high-pressure water flow b is delivered by the high-pressure water pump into the second cavity 18, and interacts with the second turbine 402 in the spiral hole expansion and slag discharge pipe 4 to drive the spiral hole expansion and slag discharge pipe 4 to rotate, and the high-pressure water flow b is sprayed out from the recoil hole 3 in the opposite direction and acts together with the rotating spiral protrusion 401 to push the coal slag, and the crushed coal slag is discharged along the drill hole.

[0023] After the dredging is completed, the borehole support is carried out; first, the high-pressure water flow a is replaced with high-pressure gas to drain the water in the first cavity 17 and the first high-pressure flexible hose 16, and then the high-pressure water flow b is replaced with high-pressure liquid nitrogen, so that the high-pressure liquid nitrogen enters the second cavity 18 through the second high-pressure flexible hose 15, and then sprays out from the recoil hole 3 to temporarily freeze and fix the place that needs support; then the micro motor 11 is used to drive the threaded spiral tube 10 to rotate and push the spiral spring support tube to the front end of the coal-breaking drill bit 2, so that the spiral spring support tube is sent out through the spiral protrusion 401 and the outer wall thread 203 of the drill bit to support the collapsed hole of the gas extraction borehole. When the dredging and support of the collapsed hole of the coal seam gas extraction borehole are completed, the micro motor 11 is controlled to drive the threaded spiral tube 10 to rotate in the opposite direction to withdraw the coal-breaking drill bit 2 from the spiral spring support tube.

[0024] Since the inner diameter of the spiral spring support tube as a support component is slightly larger than the outer diameter of the thread depression of the threaded spiral tube 10, the front end of the spiral spring support tube is just stuck in the thread depression of the threaded spiral tube 10 in the initial state without the support link, and the spiral spring support tube will move forward as a whole with the support drilling device. The threaded spiral tube 10 is equivalent to a "bolt", and the spiral spring support tube is equivalent to a "nut". When the threaded spiral tube 10 rotates in the opposite direction, the threaded spiral tube 10 and the spiral spring support tube move in opposite directions; and since the inner diameter of the spiral spring support tube is slightly larger than the outer diameter of the thread depression of the spiral protrusion 401 and the outer wall thread 203 of the drill bit, the spiral spring support tube passes through the spiral protrusion 401 and the depression of the outer wall thread 203 of the drill bit and is sent into the borehole.

[0025] During the withdrawal of the support drilling device, the threaded spiral tube 10 is in contact with the spiral spring support tube, and the threaded spiral tube 10 is separated from the spiral spring support tube at the later stage of withdrawal. When the end of the spiral spring support tube with a certain length leaves the threaded spiral tube 10, the support drilling device is already at the end of the spiral spring support tube. Since the spiral spring support tube fits the inner wall of the borehole, and its front end is located in the area where the borehole is prone to collapse and has a tendency to collapse, due to the pressure of the surrounding coal and rock, the spiral spring support tube already has a certain restraining force. At this time, the front end of the coal-breaking drill bit 2 is separated from the spiral spring support tube by means of the backward external force, so that the support drilling device as a whole is completely withdrawn from the spiral spring support tube.

[0026] The above content is a further detailed description of the present invention in combination with a specific preferred embodiment. It cannot be determined that the specific embodiments of the present invention are limited to this. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the present invention, which should be regarded as belonging to the present invention and the scope of patent protection determined by the submitted claims.

Claims

1. A gas extraction borehole collapse dredging and support drilling device, characterized in that: It comprises a coal breaking and dredging part and a supporting and pushing pipe part; the coal breaking and dredging part comprises a coal breaking drill bit (2), an outer tube (7) and an inner tube (9) all of which are hollow structures; the inner tube (9) is fixedly arranged inside the outer tube (7); a first high-pressure flexible hose (16) is connected to the rear end of the inner tube (9); and a second high-pressure flexible hose (15) is connected to the rear end of the outer tube (7); The coal-breaking drill bit (2) is rotatably connected to the inner tube (9) via a first bearing (6); the front end of the coal-breaking drill bit (2) extends outside the outer tube (7) to form an enlarged drill bit portion; the outer edge of the drill bit portion is provided with a drill bit outer wall thread (203); the front end of the coal-breaking drill bit (2) is provided with a front nozzle (1); a first turbine (201) is provided on the cavity wall of a first cavity (17) inside the coal-breaking drill bit (2); a recoil hole (3) is formed between the coal-breaking drill bit (2) and the front end of the outer tube (7); the outer tube (7) A spiral hole expansion and slag discharge pipe (4) is rotatably connected to the outer tube (7), and both ends of the threaded hole expansion and slag discharge pipe (4) are respectively connected to the tube wall of the outer tube (7) through second bearings (5), so that the threaded hole expansion and slag discharge pipe (4) can rotate on the outer tube (7); and the threaded hole expansion and slag discharge pipe (4) is located outside the side wall of the coal breaking drill bit (2); a spiral protrusion (401) is provided on one side of the threaded hole expansion and slag discharge pipe (4) located outside the outer tube (7), and a second turbine (402) is provided on one side of the threaded hole expansion and slag discharge pipe (4) located inside the outer tube (7); The support pipe pushing part comprises a support pipe (19), a threaded spiral pipe (10) and a micro motor (11); the front end of the support pipe (19) is connected to the rear end of the outer pipe (7); two threaded spiral pipes (10) are symmetrically mounted on the pipe wall of the support pipe (19); both ends of the threaded spiral pipe (10) are rotatably connected to the pipe wall of the support pipe (19) via bearings, and the threaded spiral pipe (10) is fixedly connected to the drive shaft of the micro motor (11); the inner wall of the spiral spring support pipe is threadedly connected to the outer wall of the threaded spiral pipe (10); the outer wall thread (203) of the drill bit, the spiral protrusion (401) and the outer thread of the threaded spiral pipe (10) are all located on the same circumferential surface, so that the spiral spring support pipe is pushed into the borehole along the support pipe (19), the outer pipe (7) and the coal breaking drill bit (2).

2. A gas extraction borehole collapse dredging and support drilling device according to claim 1, characterized in that: The coal-breaking drill bit (2), the outer tube (7) and the inner tube (9) are all coaxially arranged.

3. A gas extraction borehole collapse dredging and support drilling device according to claim 1, characterized in that: The outer wall of the inner tube (9) and the inner wall of the outer tube (7) are cross-connected via a connecting rod (8); the connecting rod (8) is made of a rectangular metal block.

4. A gas extraction borehole collapse dredging and support drilling device according to claim 1, characterized in that: An irregular crushing protrusion (202) is provided on the end surface of the front end of the coal crushing drill bit (2).

5. A gas extraction borehole collapse dredging and support drilling device according to claim 1, characterized in that: The rear end of the support pipe (19) is connected to the outer wall of the subsequent pipeline (14) via a threaded structure.

6. A gas extraction borehole collapse dredging and support drilling device according to claim 1, characterized in that: The micro motor (11) is externally wrapped with a steel half cylinder (12).

7. A method for clearing and supporting gas extraction borehole collapse, characterized in that: A gas extraction borehole collapse dredging and support drilling device according to any one of claims 1 to 6, comprising the following steps: S1, high-pressure water flow a enters the first cavity (17) through the first high-pressure flexible hose (16), and interacts with the first turbine (201) in the coal-breaking drill bit (2) in the first cavity (17) to drive the coal-breaking drill bit (2) to rotate and to break up coal blocks and clear blocked collapsed holes together with the high-pressure water flow a ejected from the front nozzle (1); at the same time, high-pressure water flow b enters the second cavity (18) between the outer tube (7) and the inner tube (9), and interacts with the second turbine (402) in the spiral hole-expanding slag-discharging pipe (4) to drive the spiral hole-expanding slag-discharging pipe (4) to rotate, and the high-pressure water flow b is ejected in the reverse direction from the recoil hole (3) and acts together with the rotating spiral protrusion (401) to push the coal slag, so that the broken coal slag is discharged along the drill hole; S2. After the dredging is completed, the borehole is supported: first, the high-pressure water flow a is replaced by high-pressure gas to drain the water in the first cavity (17) and the first high-pressure flexible hose (16); then, the high-pressure water flow b is replaced by high-pressure liquid nitrogen, so that the high-pressure liquid nitrogen enters the second cavity (18) through the second high-pressure flexible hose (15) and is then ejected from the recoil hole (3) to temporarily freeze and fix the area that needs support; then, a micro motor (11) is used to drive the threaded spiral tube (10) to rotate and push the spiral spring support tube toward the front end of the coal-breaking drill bit (2), so that the spiral spring support tube is sent out through the spiral protrusion (401) and the thread (203) on the outer wall of the drill bit to support the collapsed area of ​​the gas extraction borehole.

Images