A device and method for progressive jet coal breaking and permeability enhancement by high-pressure air carrying materials in extremely soft coal seams

Abstract

The present invention relates to a device and method for progressive jet coal breaking and permeability enhancement by high-pressure air carrying materials in extremely soft coal seams, belonging to the technical field of coal mine gas disaster control. The device of the present invention is provided with a male connector and a female connector at both ends, and a piston moving axially is arranged in the inner cavity. Low-pressure gas channels are arranged around the cavity wall to connect the drill bit, and high-pressure gas channels are connected to the hollow pins of the wing drills. The internal drainage nozzle in the high-pressure gas jet channel sucks coal powder through the sieve holes, and the high-pressure air carrying materials are progressively ejected through the conical nozzle. The present invention generates compressed air through an air compressor and a high-pressure gas cylinder, which enters the device and the drill bit. During drilling, low-pressure gas is used for cooling and slag discharge, and when breaking coal, the high-pressure gas is switched to push the wing drill to rotate and open to implement mechanical cavity formation, and at the same time, the high-pressure gas carries materials for progressive jet coal breaking. The present invention can effectively solve the problem that conventional hydraulic measures cannot be used for coal seam pressure relief and permeability enhancement in extremely soft coal seams in coal mines, and further realize efficient extraction of coal seam gas and ensure the safe production of coal mining enterprises.

Description

Technical Field

[0001] The invention belongs to the technical field of coal processing, and relates to a device and method for increasing the permeability of extremely soft coal seams by progressive injection of high-pressure air carrying materials. Background Art

[0002] my country's deep mines show significant "three highs and one low" characteristics, namely high ground stress, high pore pressure, high temperature and low permeability. At present, the conventional gas extraction methods for low-permeability coal seams are not ideal. Domestic research institutes and universities have developed a series of technologies and equipment related to enhanced gas extraction, mainly including mechanical cavitation and hydraulic measures (hydraulic punching, hydraulic cutting, hydraulic fracturing, etc.). Mechanical cavitation is to install divergent mechanical claws behind the drill bit. After the drilling construction reaches the designed depth, the low-pressure water is switched to high-pressure water. The mechanical claws are propped up while the drill rod is rotated to cut the coal wall. For extremely soft coal seams, the coal body space can be increased. However, the energy consumption of a single mechanical cavitation is too high, and the size of the increased coal body space is limited, resulting in a significant reduction in the coal drop effect. Hydraulic measures use high-pressure water to destroy the borehole coal wall, so that a larger free space is formed in the coal body, which is conducive to coal body pressure relief and permeability enhancement. However, for extremely soft coal seams, the presence of water in the coal body after hydraulic measures has a negative impact on gas desorption and migration. The low porosity and low permeability characteristics of the coal body make the water lock effect particularly prominent; the presence of water can also easily cause coal body mudification and block the gas extraction channel; it is difficult to control the impact of the coal body volume, and it is easy to form an oversized space, causing local stress concentration, inducing blowholes or protrusions. How to relieve pressure and increase permeability of extremely soft coal seams in coal mines and ensure efficient extraction of coal seam gas is of great significance for ensuring the balance of mining and extraction in mines while ensuring safe production in coal mines.

[0003] The prior art discloses a coal seam hole enlargement and permeability enhancement method using pneumatic coupling (CN201910796409.1). This method has a large hole enlargement diameter and is not prone to hole collapse during the hole enlargement process. It can effectively enlarge and enhance the permeability of soft coal seams. However, this method requires the insertion of drill bits of different diameters for variable diameter expansion, and the hole enlargement construction process is complicated. The prior art also discloses a directional shock wave generating device and a gas extraction method for soft coal seams based on the device (CN201911017526.X) and a pneumatic pulse punching and permeability enhancement method for low permeability soft coal seams (CN202111623861.1). These methods can solve the problems encountered in the hydraulic measures for low permeability soft coal seams, improve the gas extraction efficiency, and avoid hole collapse, hole blocking, and drill burial. However, these methods require the use of multiple shock waves and pulse generating devices, which are greatly restricted by on-site conditions, have complex construction processes, and have poor reliability of permeability enhancement effects.

[0004] Therefore, it is necessary to conduct further research and exploration on the equipment and methods for high-pressure air-carrying progressive injection to break coal and increase permeability in extremely soft coal seams. Summary of the invention

[0005] In view of this, one of the objectives of the present invention is to provide a device for progressive jet coal breaking and permeability enhancement in extremely soft coal seams with high-pressure air carrying materials; another objective of the present invention is to provide a method for progressive jet coal breaking and permeability enhancement in extremely soft coal seams with high-pressure air carrying materials.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] 1. A device for progressive jet coal breaking and permeability enhancement in extremely soft coal seams with high-pressure air carrying materials, the device 24 includes a cavity wall 1 and a channel inlet 2, a spring 3, a piston 4, a low-pressure gas channel 5, a low-pressure gas channel outlet 6, a male connector 7, a vane bin 8, a vane drill 9, a limit block 10, a clamping ring 11, a high-pressure gas channel 12, a high-pressure gas channel inlet 13, and a female connector 14 arranged inside the cavity wall;

[0008] The front part of the device 24 is provided with a male connector 7, and the rear part is provided with a female connector 14;

[0009] A piston 4 capable of moving along the axial direction of the device is arranged in the inner cavity of the device 24, and a spring 3 is sleeved in the middle section of the piston 4;

[0010] The middle part of the device 24 is provided with a low-pressure gas channel inlet 2, and one end of the low-pressure gas channel 5 arranged on the cavity wall 1 of the device 24 is connected to the low-pressure gas channel inlet 2; the rear part of the device 24 is provided with a low-pressure gas channel outlet 6, and the other end of the low-pressure gas channel 5 is connected to the low-pressure gas channel outlet 6;

[0011] A high-pressure gas channel inlet 13 is connected to the rear part of the device 24 and the female connector 14, and the high-pressure gas channel inlet 13 is sequentially connected to the high-pressure gas channel 12 arranged along the cavity wall 1 and the vane drill 9. The vane drill 9 is fixed in the vane bin 8 through the limit block 10;

[0012] A clamping ring 11 is arranged between the high-pressure gas channel 12 and the piston 4.

[0013] Preferably, the piston 4 is divided into a five-section structure according to its function, including a cylindrical channel 4-1, a sealing ring 4-2, and a gear structure 4-3;

[0014] A plurality of cylindrical channels 4-1 are arranged in the first section at the rear of the piston 4. The number of the cylindrical channels 4-1 is the same as the number of the low-pressure gas channels 5, and the rear ends of the cylindrical channels 4-1 are directly in contact with the gas flow direction;

[0015] The second section in the middle of the piston 4 is a circular cavity, and the compressed gas in the circular cavity directly enters through the cylindrical channels 4-1;

[0016] At the contact position between the third section in the middle of the piston 4 and the cavity wall 1, a sealing ring 4-2 is used for sealing to prevent the gas in the annular cavity from entering the front part of the piston 4;

[0017] A spring 3 is sleeved on the fourth section in the middle of the piston 4. The spring 3 is in close contact with the clamping ring 11. When the spring 3 is subjected to the gas pressure, it contracts and deforms, causing the piston 4 to move as a whole in the air flow direction. When the spring 3 is not under pressure, it automatically expands and returns to its natural state, causing the piston 4 to move as a whole in the reverse air flow direction;

[0018] A gear structure 4-3 that contacts the vane drill 9 is arranged on the fifth section at the front part of the piston 4. The gear structure 4-3 and the vane drill gear structure 9-6 are coupled with each other, and when the piston 4 moves, it pushes the vane drill 9 to rotate.

[0019] Preferably, the vane drill 9 includes a hollow shaft pin 9-1, a high-pressure gas jet channel 9-2, a drainage nozzle 9-3, sieve holes 9-4, a conical nozzle 9-5, and a vane drill gear structure 9-6;

[0020] The high-pressure gas channel 12 is connected to the hollow shaft pin 9-1 of the vane drill 9. Inside the high-pressure gas jet channel 9-2 of the vane drill 9, the internal drainage nozzle 9-3 sucks in pulverized coal through the sieve holes 9-4, and the high-pressure air carries the material and is progressively sprayed through the conical nozzle 9-5;

[0021] The vane drill 9 is provided with a vane drill gear structure 9-6 that contacts the gear structure 4-3 on its outer edge. The gear structure 4-3 and the vane drill gear structure 9-6 are coupled with each other, and when the piston 4 moves, it pushes the vane drill 9 to rotate; at the same time, 6 to 8 parallel-arranged button bits 9-7 are provided on the outer edge of the vane drill 9, and after the vane drill 9 is opened, the button bits 9-7 are used to mechanically cut the coal body.

[0022] 2. A method for high-pressure air-carrying progressive jet coal breaking and permeability enhancement in extremely soft coal seams. The method is carried out by using the above-mentioned device 24, and specifically includes:

[0023] Step 1: Generate compressed air through an air compressor and a high-pressure gas cylinder in the coal mine. Control the opening and closing of the compressed air pipeline by using the front-end valve and the rear-end valve, and observe the change of the compressed air pressure through a pressure gauge;

[0024] Step 2: Carry out the normal construction of drilling holes into the coal seam by using a drill. During the construction process, low-pressure compressed air enters the progressive jet device and the drill bit through the tail high-pressure sealed rotary joint and the drill pipe, cools down and discharges slag from the above-mentioned device and the drill bit during the normal construction process, and normally drills the hole into the coal seam to a predetermined position by using low-pressure compressed gas;

[0025] Step 3: Switch the high-pressure compressed gas through the front-end valve and the rear-end valve. After switching to high-pressure gas, the piston moves to block the inlet 2 of the low-pressure gas passage. All the high-pressure gas enters from the high-pressure gas passage inlet 13, pushing the vane drill 9 of the above-mentioned device 24 to rotate and open to 90° to implement mechanical cavity formation. The mixed abrasive jet is ejected through the conical nozzle 9-5 at the front end of the high-pressure gas jet passage 9-2 to implement progressive jet coal breaking;

[0026] Step 4: After completing the mechanical cavity formation and progressive jet coal breaking at a certain position in the drilling, control the forward and backward movement of the above-mentioned device 24 through the drill rig, and repeat step (3) to perform mechanical cavity formation and progressive jet coal breaking at different positions of the coal seam until the construction is completed.

[0027] Preferably, the male joint 7 of the above-mentioned device 24 and the drill bit are directly connected by threads, and the female joint 14 of the above-mentioned device 24 and the drill pipe are directly connected by threads, and reach a predetermined position in the coal seam during the drilling process.

[0028] The beneficial effects of the present invention are as follows: The present invention discloses a high-pressure air-carrying progressive jet coal-breaking and permeability-increasing device for extremely soft coal seams, which has the following advantages: (1) The device of the present invention is axially provided with a piston sleeved with a spring, which can automatically control the opening and closing of the vane drill according to the magnitude of the compressed air pressure. The structure design is simple and the opening and closing timing is easy to control; (2) The device of the present invention arranges a low-pressure gas passage and a high-pressure gas passage along the cavity wall, which can prevent the drill bit and the vane drill from being blocked and cool down and discharge slag during normal drilling, reduce the wear of the drill bit and the vane drill, and reduce the costs of drilling construction and cavity formation and reaming; (3) The device of the present invention sets a drainage nozzle and sieve holes inside the vane drill to form a coal powder and high-pressure gas mixed abrasive jet, which can make full use of the compression internal energy of the air to be converted into the kinetic energy of carrying materials to break coal, greatly expand the coal body space, and effectively increase the gas permeability of the coal seam.

[0029] The present invention also discloses a high-pressure air-carrying progressive jet coal-breaking and permeability-increasing method for extremely soft coal seams. During the construction process, mechanical cutting and carrying progressive jet coal breaking are carried out by switching high-pressure gas, which effectively reduces the system energy consumption, the supporting equipment is simple, and the construction process is simple. At the same time, it is beneficial to prevent gas dynamic phenomena such as borehole outburst. Therefore, the device and method of the present invention are important breakthroughs in the field of coal mine gas disaster control, which can effectively solve the problem that conventional hydraulic measures cannot be used to relieve the pressure and increase the permeability of extremely soft coal seams in coal mines, and then realize the efficient extraction of coal seam gas and ensure the safe production of coal mining enterprises.

[0030] Other advantages, objects, and features of the present invention will be set forth in part in the following description, and in part will be obvious to those skilled in the art upon examination of the following, or may be learned by practice of the present invention. The objects and other advantages of the present invention may be realized and obtained by the following description. Brief Description of the Drawings

[0031] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0032] Figure 1 It is a structural diagram of the device in Embodiment 1;

[0033] Figure 2 It is a sectional view taken along line A-A of the device structure in Embodiment 1;

[0034] Figure 3 For Figure 1 a schematic diagram of the rotational expansion of the fin drill 9 in

[0035] Figure 4 For Figure 1 a structural diagram of the fin drill 9 in

[0036] Figure 5 It is a layout schematic diagram of a high-pressure air-carrying progressive jet coal-breaking and permeability-increasing method for extremely soft coal seams in Embodiment 2.

[0037] Wherein, 1 is the cavity wall, 2 is the low-pressure gas channel inlet, 3 is the spring, 4 is the piston, 4-1 is the cylindrical channel, 4-2 is the sealing ring, 4-3 is the gear structure, 5 is the low-pressure gas channel, 6 is the low-pressure gas channel outlet, 7 is the male joint, 8 is the fin chamber, 9 is the fin drill, 9-1 is the hollow pin, 9-2 is the high-pressure gas jet channel, 9-3 is the drainage nozzle, 9-4 is the sieve hole, 9-5 is the conical nozzle, 9-6 is the fin drill gear structure, 9-7 is the button bit, 10 is the limit block, 11 is the clamping ring, 12 is the high-pressure gas channel, 13 is the high-pressure gas channel inlet, 14 is the female joint, 15 is the air compressor, 16 is the front-end valve, 17 is the high-pressure gas cylinder, 18 is the rear-end valve, 19 is the pressure gauge, 20 is the high-pressure sealing rotary joint, 21 is the drill rig, 22 is the drill pipe, 23 is the borehole, 24 is the progressive jet device, 25 is the drill bit, and 26 is the coal seam. Detailed Embodiments

[0038] The following describes the implementation manners of the present invention through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0039] Embodiment 1

[0040] A high-pressure air-carrying material progressive jet coal-breaking and permeability-increasing device for extremely soft coal seams, the structure of which is as Figure 1 shown, wherein Figure 1 The A-A sectional view of the structure in Figure 2 is as described. The device 24 includes a cavity wall 1 and a channel inlet 2, a spring 3, a piston 4, a low-pressure gas channel 5, a low-pressure gas channel outlet 6, a male joint 7, a vane bin 8, a vane drill 9, a limit block 10, a clamping ring 11, a high-pressure gas channel 12, a high-pressure gas channel inlet 13, and a female joint 14 arranged inside the cavity wall.

[0041] Among them, a male joint 7 is arranged at the front part of the device 24, and a female joint 14 is arranged at the rear part.

[0042] A piston 4 capable of moving along the axial direction of the device is arranged in the inner cavity of the device 24. A spring 3 is sleeved in the middle section of the piston 4. The piston 4 is divided into a five-section structure according to its function, including a cylindrical channel 4-1, a sealing ring 4-2, and a gear structure 4-3. A plurality of cylindrical channels 4-1 are arranged in the first section at the rear of the piston 4. The number of the cylindrical channels 4-1 is the same as the number of the low-pressure gas channels 5. The rear end of the cylindrical channel 4-1 is directly in contact with the gas flow direction. The second section in the middle of the piston 4 is an annular cavity. The compressed gas in the annular cavity directly enters through the cylindrical channel 4-1. The contact position between the third section in the middle of the piston 4 and the cavity wall 1 is sealed by a sealing ring 4-2 to prevent the gas in the annular cavity from entering the front part of the piston 4. A spring 3 is sleeved in the fourth section in the middle of the piston 4. The spring 3 is in close contact with the clamping ring 11. When the spring 3 is acted on by gas pressure, it contracts and deforms, causing the piston 4 to move as a whole in the gas flow direction. When the spring 3 is not under pressure, it automatically expands and returns to its natural state, causing the piston 4 to move as a whole in the reverse gas flow direction. In addition, a gear structure 4-3 in contact with the vane drill 9 is arranged in the fifth section at the front of the piston 4. The gear structure 4-3 and the vane drill gear structure 9-6 are coupled with each other. When the piston 4 moves, it pushes the vane drill 9 to rotate. The rotation and opening schematic diagram of the vane drill 9 is as Figure 3 shown, and the structural schematic diagram of the vane drill 9 is as Figure 4As shown in the figure, the fin drill 9 includes a hollow shaft pin 9-1, a high-pressure gas jet channel 9-2, a drainage nozzle 9-3, sieve holes 9-4, a conical nozzle 9-5, and a fin drill gear structure 9-6; the high-pressure gas channel 12 is connected to the hollow shaft pin 9-1 of the fin drill 9. Inside the fin drill 9, the internal drainage nozzle 9-3 of the high-pressure gas jet channel 9-2 sucks pulverized coal through the sieve holes 9-4, and the high-pressure air carries the material and is progressively sprayed through the conical nozzle 9-5; the fin drill 9 is provided with a fin drill gear structure 9-6 on the outer edge that contacts the gear structure 4-3, and the gear structure 4-3 and the fin drill gear structure 9-6 are coupled to each other. When the piston 4 moves, it pushes the fin drill 9 to rotate; at the same time, the fin drill 9 is provided with 6 to 8 parallel button bits 9-7 on the outer edge, and after the fin drill 9 is opened, the button bits 9-7 are used to mechanically cut the coal body.

[0043] A low-pressure gas channel inlet 2 is provided in the middle of the device 24, and the low-pressure gas channel inlet 2 is connected to one end of the low-pressure gas channel 5 arranged on the cavity wall 1 of the device 24. A low-pressure gas channel outlet 6 is provided at the rear of the device 24, and the low-pressure gas channel outlet 6 is connected to the other end of the low-pressure gas channel 5.

[0044] A high-pressure gas channel inlet 13 is provided at the rear of the device 24 and is connected to the mother joint 14. The high-pressure gas channel inlet 13 is sequentially connected to the high-pressure gas channel 12 arranged along the cavity wall 1 and the fin drill 9. The fin drill 9 is fixed in the fin bin 8 through a limit block 10.

[0045] Embodiment 2

[0046] A method for breaking coal and enhancing permeability by progressive injection of high-pressure air carrying material in extremely soft coal seams. This method is carried out using the device in Embodiment 1, and its layout schematic diagram is as Figure 5 shown, and specifically includes the following steps:

[0047] (1) Compressed air is generated by an air compressor 15 and a high-pressure gas cylinder 17 in the coal mine underground. The opening and closing of the compressed air pipeline are controlled by a front-end valve 16 and a rear-end valve 18, and the change of the compressed air pressure is observed through a pressure gauge 19.

[0048] (2) A drill 21 is used to normally construct a borehole 23 in the coal seam 26. During the construction process, low-pressure compressed air enters the progressive injection device 24 and the drill bit 25 through a tail high-pressure sealed rotary joint 20 and a drill pipe 22 to cool and remove slag from the device 24 and the drill bit 25 in Embodiment 1 during the normal construction process. The borehole 23 is normally drilled into the predetermined position in the coal seam 26 using low-pressure compressed gas.

[0049] (3)Switch the high-pressure compressed gas through the front-end valve 16 and the rear-end valve 18. After switching to high-pressure gas, the piston moves to block the inlet 2 of the low-pressure gas passage. All the high-pressure gas enters from the high-pressure gas passage inlet 13, pushing the vane drill 9 of the device 24 in Embodiment 1 to rotate and open to 90° to implement mechanical cavity formation. The mixed abrasive jet is ejected through the conical nozzle 9-5 at the front end of the high-pressure gas jet passage 9-2 to implement progressive jet coal breaking;

[0050] (4)After completing the mechanical cavity formation and progressive jet coal breaking at a certain position in the borehole 23, control the forward and backward movement of the device 24 in Embodiment 1 through the drill rig, and repeat step (3) to perform mechanical cavity formation and progressive jet coal breaking at different positions of the coal seam until the construction is completed.

[0051] In the above method, the male joint 7 and the drill bit 25 of the device 24 in Embodiment 1 are directly connected by threads, and the female joint 14 of the device 24 is directly connected to the drill pipe 22 by threads, and enters a predetermined position in the coal seam 26 during the drilling process of the borehole 23.

[0052] In summary, the present invention discloses a high-pressure air-carrying progressive jet coal-breaking and permeability-increasing device for extremely soft coal seams, which has the following advantages: (1) The device of the present invention is axially provided with a piston sleeved with a spring, which can automatically control the opening and closing of the vane drill according to the magnitude of the compressed air pressure. The structure design is simple and the opening and closing timing is easy to control; (2) The device of the present invention arranges a low-pressure gas passage and a high-pressure gas passage along the cavity wall, which can prevent the drill bit and the vane drill from being blocked and cool and discharge slag during normal drilling, reduce the wear of the drill bit and the vane drill, and reduce the costs of borehole construction and cavity formation and reaming; (3) The device of the present invention sets a drainage nozzle and sieve holes inside the vane drill to form a coal powder and high-pressure gas mixed abrasive jet, which can make full use of the compression internal energy of the air to be converted into the kinetic energy of carrying materials to break coal, greatly expand the coal body space, and effectively increase the coal seam permeability. In addition, the present invention also discloses a high-pressure air-carrying progressive jet coal-breaking and permeability-increasing method for extremely soft coal seams. During the construction process, mechanical cutting and carrying progressive jet coal breaking are carried out by switching high-pressure gas, which effectively reduces the system energy consumption, the supporting equipment is simple, the construction process is simple, and at the same time it is beneficial to prevent gas dynamic phenomena such as borehole outburst. Therefore, the device and method of the present invention are important breakthroughs in the field of coal mine gas disaster control, which can effectively solve the problem that conventional hydraulic measures cannot be used to relieve the pressure and increase the permeability of extremely soft coal seams in coal mines, and then realize the efficient extraction of coal seam gas and ensure the safe production of coal mining enterprises.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A device for progressive jet coal breaking and permeability enhancement by high-pressure air carrying materials in extremely soft coal seams, characterized in that, The device (24) includes a cavity wall (1), a channel inlet (2), a spring (3), a piston (4), a low-pressure gas channel (5), a low-pressure gas channel outlet (6), a male connector (7), a fin chamber (8), a fin drill (9), a limit block (10), a clamping ring (11), a high-pressure gas channel (12), a high-pressure gas channel inlet (13), and a female connector (14) arranged inside the cavity wall; The front part of the device (24) is provided with a male connector (7), and the rear part is provided with a female connector (14); A piston (4) capable of moving axially along the device is arranged in the inner cavity of the device (24), and a spring (3) is sleeved in the middle section of the piston (4); A low-pressure gas channel inlet (2) is arranged in the middle part of the device (24), wherein the channel inlet (2) is connected to one end of a low-pressure gas channel (5) arranged on the cavity wall (1) of the device (24); a low-pressure gas channel outlet (6) is arranged at the rear part of the device (24), and the low-pressure gas channel outlet (6) is connected to the other end of the low-pressure gas channel (5); A high-pressure gas channel inlet (13) is connected to the rear part of the device (24) and the female connector (14), and the high-pressure gas channel inlet (13) is sequentially connected to a high-pressure gas channel (12) arranged along the cavity wall (1) and a fin drill (9), and the fin drill (9) is fixed in the fin chamber (8) through a limit block (10); A clamping ring (11) is arranged between the high-pressure gas channel (12) and the piston (4); The piston (4) is divided into a five-section structure according to its function, including a cylindrical channel (4-1), a sealing ring (4-2), and a gear structure (4-3); A number of cylindrical channels (4-1) are arranged in the first section at the rear of the piston (4), the number of the cylindrical channels (4-1) is the same as that of the low-pressure gas channels (5), and the rear ends of the cylindrical channels (4-1) are directly in contact with the gas flow direction; The second section in the middle of the piston (4) is a circular cavity, and the compressed gas in the circular cavity directly enters through the cylindrical channel (4-1); The contact position between the third section in the middle of the piston (4) and the cavity wall (1) is sealed with a sealing ring (4-2) to prevent the gas in the circular cavity from entering the front part of the piston (4); A spring (3) is sleeved in the fourth section in the middle of the piston (4), and the spring (3) is in close contact with the clamping ring (11). When the spring (3) is subjected to gas pressure, it contracts and deforms, causing the piston (4) to move as a whole in the gas flow direction. When the spring (3) is not under pressure, it automatically expands and returns to its natural state, causing the piston (4) to move as a whole in the reverse gas flow direction; A gear structure (4-3) in contact with the fin drill (9) is arranged in the fifth section at the front of the piston (4), and the gear structure (4-3) and the fin drill gear structure (9-6) are coupled with each other, and the fin drill (9) is pushed to rotate when the piston (4) moves.

2. The device according to claim 1, wherein The vane drill (9) includes a hollow shaft pin (9-1), a high-pressure gas jet channel (9-2), a drainage nozzle (9-3), a sieve hole (9-4), a conical nozzle (9-5), and a vane drill gear structure (9-6); The high-pressure gas channel (12) is connected to the hollow shaft pin (9-1) of the vane drill (9). The internal drainage nozzle (9-3) of the high-pressure gas jet channel (9-2) in the vane drill (9) sucks in pulverized coal through the sieve hole (9-4), and the high-pressure air carries the material and is progressively sprayed through the conical nozzle (9-5); The vane drill (9) is provided with a vane drill gear structure (9-6) on the outer edge that contacts the gear structure (4-3). The gear structure (4-3) and the vane drill gear structure (9-6) are coupled to each other, and when the piston (4) moves, it drives the vane drill (9) to rotate. At the same time, the vane drill (9) is provided with 6 to 8 button teeth (9-7) arranged in parallel on the outer edge, and after the vane drill (9) expands, the button teeth (9-7) are used to mechanically cut the coal body.

3. A method for progressive jet coal breaking and permeability enhancement by high-pressure air carrying materials in extremely soft coal seams, characterized in that, The method is carried out using the device described in any one of claims 1 to 2, and specifically includes: Step 1: Compressed air is generated by an air compressor and a high-pressure gas cylinder underground in the coal mine. The opening and closing of the compressed air pipeline are controlled by a front-end valve and a rear-end valve (18), and the change in the compressed air pressure is observed through a pressure gauge; Step 2: The normal construction of drilling a hole into the coal seam is carried out using a drill rig. During the construction process, low-pressure compressed air enters the progressive injection device and the drill bit through a tail high-pressure sealed rotary joint and a drill pipe to cool and discharge slag from the device (24) and the drill bit described in any one of claims 1 to 2 during the normal construction process, and the hole is normally drilled into the coal seam to a predetermined position using low-pressure compressed gas; Step 3: The high-pressure compressed gas is switched through the front-end valve and the rear-end valve. After switching to high-pressure gas, the piston moves to block the low-pressure gas channel inlet (2), and all the high-pressure gas enters from the high-pressure gas channel inlet (13), pushing the vane drill (9) of the device (24) described in any one of claims 1 to 2 to rotate and expand to 90° to implement mechanical cavity formation. The mixed abrasive jet is ejected through the conical nozzle (9-5) at the front end of the high-pressure gas jet channel (9-2) to implement progressive jet coal breaking; Step 4: After completing the mechanical cavity formation and progressive jet coal breaking at a certain position in the hole, the device (24) described in any one of claims 1 to 2 is controlled to move forward and backward by the drill rig, and step 3 is repeated to carry out mechanical cavity formation and progressive jet coal breaking at different positions of the coal seam until the construction is completed.

4. The method according to claim 3, wherein The male joint (7) of the device (24) described in any one of claims 1 to 2 and the drill bit are directly connected by threads, and the female joint (14) of the device (24) described in any one of claims 1 to 2 is directly connected to the drill pipe by threads and enters a predetermined position in the coal seam during the drilling process of the hole.

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