A device and method for breaking coal, unloading pressure and increasing permeability by using pneumatic flexible cutters in soft coal seams

Abstract

The present invention discloses a device and method for breaking coal, relieving pressure and increasing permeability by using a pneumatic flexible tool in a soft coal seam, which comprises: a drilling rig, in which a drill rod is installed, and the shaft of the drill rod is provided with an air flow cavity of a columnar structure, and the outer ring wall of the top end of the drill rod at the outermost end is provided with a partial thread; an air compressor pump, the output end of which is sealed and connected to the air flow cavity through a high-pressure air pipe; pneumatic slitting equipment, which comprises a pneumatic rotating device and a slitting device, the left end of the pneumatic rotating device is installed on the top end of the drill rod at the outermost end, and the right end of the pneumatic rotating device is installed with the slitting device, and the drill rod, the pneumatic rotating device and the slitting device are all coaxially arranged.

Description

Technical Field

[0001] The invention relates to the technical field of coal seam gas extraction, and in particular to a device and method for breaking coal, relieving pressure and increasing permeability by using a pneumatic flexible tool in a soft coal seam. Background Art

[0002] As my country's basic energy and industrial raw material, coal has long provided a strong guarantee for economic and social development and the safe and stable supply of national energy. However, my country's deep mines are widely distributed, and the coal seams in most mining areas have low permeability. Gas outbursts are one of the main disasters in various regions, posing a serious threat to mine safety production. At the same time, as an efficient and clean energy, if gas can be effectively mined and utilized, it will not only eliminate the safety hazards of coal mines, but also alleviate my country's energy shortage. Gas extraction is the basic means of developing and utilizing gas resources. When gas extraction is carried out underground in coal mines, the effect of gas extraction mainly depends on the permeability of the coal seams. However, most of the coal seams in my country's coal mines with gas are generally low-permeability and soft coal seams, with soft coal quality and poor permeability. Improving the permeability of low-permeability and soft coal seams is an urgent requirement for coal mine safety production and efficient development and utilization of gas resources.

[0003] At present, the methods used for coal seam pressure relief and permeability enhancement can generally be divided into mechanical methods and physical and chemical methods. Mechanical methods generate new cracks by changing the stress distribution, thereby improving the permeability of the reservoir, including cavitation technology, hydraulic fracturing, water jet expansion (or slit), etc.; for example, the invention patents with application numbers 202010539997.3 and 202010539985.0 both use hydraulic cavitation technology for coal seam pressure relief and permeability enhancement. The principle is to use the drill pipe to transport the high-pressure nozzle to the designated position, and the high-pressure water reaches the high-pressure nozzle through the drill pipe to form a high-pressure jet to crush the coal body. The rotation of the drill pipe drives the nozzle to rotate, and the hole wall is hit all around to form a large-diameter cavitation. However, hydraulic cavitation, hydraulic fracturing, water jet expansion (or slit) and other hydraulic coal seam pressure relief and permeability enhancement technologies are prone to hole collapse and drill holding in soft coal seams; in addition, the water lock effect has a negative impact on the desorption and migration of gas in the coal body. Studies have shown that the low permeability of coal seams aggravates the water lock effect, which has a serious impact on its application in soft coal seams. Therefore, the application of hydraulic pressure relief and permeability enhancement technology in soft coal seams should be avoided. For example, the invention patent with application number 201510006074.0, entitled "High-pressure abrasive gas jet coal breaking pressure relief and permeability enhancement equipment and method", mixes high-pressure air with abrasives, and the high-pressure abrasive air jet formed after the mixture is transported to the nozzle to erode the coal body. Although this method avoids the negative effects of collapse and water lock when hydraulic measures are applied in soft coal seams, during the construction process, the high-pressure abrasive jet will cause great damage to the conveying pipeline, and has extremely high requirements for the pipeline material; at the same time, the abrasive will be mixed with coal slag after erosion, which is difficult to reuse, and the construction cost is relatively high.

[0004] Therefore, those skilled in the art provide a device and method for breaking coal, relieving pressure and increasing permeability by using pneumatic flexible cutters in soft coal seams to solve the problems raised in the above-mentioned background technology. Summary of the invention

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a pneumatic flexible tool coal breaking, pressure relief and permeability enhancement device in a soft coal seam, comprising:

[0006] A drilling rig, wherein a drill rod is installed inside, and the shaft of the drill rod is provided with a columnar airflow cavity, and the outer ring wall of the top end of the drill rod at the outermost end is provided with a partial thread;

[0007] An air compressor pump, the output end of which is sealedly connected to the air flow cavity through a high-pressure air pipe;

[0008] The pneumatic slitting device comprises a pneumatic rotating device and a slitting device, wherein the left end of the pneumatic rotating device is installed on the top end of the drill rod at the outermost end, the right end of the pneumatic rotating device is installed with the slitting device, and the drill rod, the pneumatic rotating device and the slitting device are all coaxially arranged.

[0009] As a preferred technical solution of the present invention, the pneumatic rotating device comprises:

[0010] A cylindrical housing, the left end of which is engaged and fixed with a thread corresponding to the top end of the drill rod;

[0011] The drainage block frame includes a hemispherical shell one-way cone cap, wherein the left portion of the hemispherical shell one-way cone cap is a hemispherical shell structure, and the right portion thereof is a cone structure, and drainage strips arranged in a circumferential manner and axially fixedly laid on the outside of the hemispherical shell one-way cone cap and whose upper ends are fixed to the inner shell wall of the cylindrical shell, wherein the left portion of the drainage strips is a flat plate, and the right portion thereof is an arc-shaped plate structure;

[0012] The rotating module is coaxially connected to the right part of the one-way cone cap of the hemispherical shell.

[0013] As a preferred technical solution of the present invention, the rotating module includes:

[0014] The first rotor comprises a rotating shaft whose left end is coaxially connected to the right part of the one-way cone cap of the hemispherical shell, and an arc-shaped guide vane 1 is arranged on the outer ring wall of the rotating shaft near the left end and fixedly laid in a circumferential manner and axially pointing thereto;

[0015] The flow-correcting sleeve fan comprises a bidirectional cone cap which is sleeved on the outside of the rotating shaft 91 and is rotatably connected. The central annular outer wall of the bidirectional cone cap is fixed with DC fan plates arranged in a circumferential manner and whose upper end faces are all fixed to the inner shell wall of the cylindrical shell;

[0016] The second rotor includes a rotating shaft cylinder which is arranged at the right end of the bidirectional cone cap and is sleeved on the outside of the rotating shaft 91 and rotatably connected. On the outer ring wall of the rotating shaft cylinder at the left end, arc-shaped guide vanes 2 are arranged in a circle and fixedly laid in the axial direction.

[0017] As a preferred technical solution of the present invention, the arc guide vane 1 and the arc guide vane 2 are arranged in a centrally symmetrical structure, and the number of the arc guide vane 1 and the arc guide vane 2 are arranged in a one-to-one correspondence, and the lower bending trend of the arc vane at the right end of the arc guide vane 1 92 and the upper bending trend of the arc guide vane 2 102 and the left end arc vane are in a tangent structure and are both axially pointed.

[0018] As a preferred technical solution of the present invention, the conical curved surface wall in the hemispherical shell one-way cone cap is an inclined surface that is convex and inclined at 30°.

[0019] As a preferred technical solution of the present invention, the bidirectional cone cap is symmetrically arranged on the left and right, and its left side structure is consistent with the right cone structure of the hemispherical shell unidirectional cone cap.

[0020] As a preferred technical solution of the present invention, the slitting device comprises:

[0021] A bearing ring 21 is coaxially mounted on the right end of the cylindrical housing 7;

[0022] The adapter shaft cylinder is sleeved on the outside of the rotating shaft cylinder and fixedly connected, and its outer ring wall is embedded in the inner ring wall of the bearing ring 21 for rotational connection, and the inner ring wall of the cylinder is provided with an axially directed and circumferentially arranged air leakage cavity 1, and each group of the air leakage cavity 1 is provided with a radially outwardly directed air leakage cavity 2 at the right end, and a dust-proof and breathable net is installed in each of the air leakage cavity 2, and the outer ring wall of the adapter shaft cylinder near the right end is provided with threaded holes arranged circumferentially;

[0023] A stud, embedded in the threaded hole for meshing connection;

[0024] Flexible tool 1, comprising whip rings, which are configured into multiple groups and are sequentially connected in a series to form a strip whip structure, with a slit blade provided on the outer ring wall, and one end of each group of the strip whips is welded to the corresponding stud;

[0025] Flexible tool 2 has the same structure as flexible tool 1 and is installed on the outer shaft ring wall at the right end of the rotating shaft 91.

[0026] As a preferred technical solution of the present invention, the upper bending trend of the arc plate at the left end of each group of the arc-shaped guide plate 92 is tangent to the lower bending trend of the arc plate at the right end of the right part of the corresponding group of drainage strips and forms an angle of 30° with the axial direction. The spacing between the drainage ends of adjacent drainage strips, the spacing between the left inlet ends of adjacent arc-shaped guide plates, and the spacing between the right end of the corresponding drainage strip and the left end of the arc-shaped guide plate are all relatively consistent.

[0027] A method for breaking coal, unloading pressure and increasing permeability by using a pneumatic flexible tool in a soft coal seam, comprising the following steps:

[0028] S1: Connect the air compressor, high-pressure air pipe and drilling rig, and connect the drill rod to the pneumatic rotating device and cutting device;

[0029] S2: Adjust the drill rod angle and align the cutting device with the designated position of the coal body;

[0030] S3: Turn on the air compressor and deliver the high-pressure gas to the pneumatic rotating device through the high-pressure gas pipe and the drill pipe;

[0031] S4: The pneumatic rotating device drives the slitting device to rotate, and the slitting device starts to drive the flexible cutter 1 and the flexible cutter 2 to rotate and break the coal. When the hole diameter reaches the hole depth, the air pressure is reduced, the slitting device stops rotating, and the flexible cutter 1 and the flexible cutter 2 lose the power to break the coal;

[0032] S5: Repeat steps S3-S4 until the entire drilling construction is completed;

[0033] S6: After the permeability enhancement of a coal hole is completed, the permeability enhancement equipment is exited and other drilling holes are prepared:

[0034] S7: Repeat steps S2-S6 until all the boreholes are depressurized and permeability enhanced.

[0035] Compared with the prior art, the present invention provides a device and method for breaking coal, unloading pressure and increasing permeability by using a pneumatic flexible tool in a soft coal seam, which has the following beneficial effects:

[0036] 1. The present invention adopts the method of converting air pressure into rotational kinetic energy, which avoids the problem of collapse of soft coal seams caused by hydraulic measures in each soft layer; the mechanical chain is used to break the coal, which increases the coal breaking efficiency and improves the pressure relief and permeability enhancement effect. At the same time, the air pressure method reduces the construction cost and is suitable for soft coal seams. It has the advantages of simple operation, low price and easy recovery.

[0037] 2. The device of the present invention mainly uses mechanical fracturing and is supplemented by pneumatic fracturing. At the same time, it reduces the embedding rate of coal blocks and coal powder in the flexible tool 1 and the flexible tool 2, improves the flexibility of coal breaking, pressure relief and permeability enhancement, implementation convenience, cutting efficiency and cutting strength, and the structural design of the flexible tool 1 and the flexible tool 2 makes it flexible and scalable, and uses a semi-automatic irregular torsional grinding and rubbing method to enhance the coal breaking strength and effectively protect the blade of the cutting blade. Finally, the coal hole diameter reaches the predetermined diameter, further improving the pressure relief and permeability enhancement strength, accuracy and effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic structural diagram of the pneumatic flexible tool coal breaking, pressure relief and permeability enhancement device of the present invention;

[0039] Figure 2 It is an enlarged schematic diagram of a partial cross-section structure of the pneumatic slitting device of the present invention;

[0040] Figure 3 It is an enlarged schematic diagram of the local structure of the pneumatic slitting equipment of the present invention;

[0041] Figure 4 It is an enlarged schematic diagram of the local structure of the transfer shaft cylinder of the present invention;

[0042] Figure 5 It is a schematic diagram of the pneumatic principle implementation of the present invention;

[0043] In the figure: 1, air compressor; 2, high pressure air pipe; 3, drilling rig; 4, drill rod; 5, pneumatic slotting equipment; 6, pneumatic rotating device; 7, cylindrical shell; 8, drainage block frame; 9, first rotor; 10, second rotor; 11, flow correction sleeve fan frame; 12, fan-shaped strip; 13, slotting device; 14, adapter shaft; 15, flexible tool 1; 16, threaded hole; 17, slotting blade; 18, stud; 19. Whip ring; 20. Rotation module; 21. Bearing ring; 22. Flexible tool 2; 81. Hemispherical shell one-way cone cap; 82. Drainage strip; 91. Rotation axis; 92. Arc guide vane 1; 101. Rotation shaft cylinder; 102. Arc guide vane 2; 111. Bidirectional cone cap; 112. DC fan plate; 141. Vent cavity 1; 142. Vent cavity 2; 143. Dust-proof and breathable net. DETAILED DESCRIPTION

[0044] Reference Figure 1-5 The present invention provides a technical solution: a pneumatic flexible tool coal breaking, pressure relief and permeability enhancement device in a soft coal seam, comprising:

[0045] A drilling rig 3, in which a drill rod 4 is installed, and the shaft of the drill rod 4 is provided with a columnar airflow cavity, and the outer ring wall of the top end of the drill rod 4 at the outermost end is provided with a partial thread;

[0046] The air compressor 1, whose output end is sealed and connected to the air flow cavity through the high-pressure air pipe 2;

[0047] A pneumatic slitting device 5, comprising a pneumatic rotating device 6 and a slitting device 13, wherein the left end of the pneumatic rotating device 6 is mounted on the top end of the drill rod 4 at the outermost end, and the slitting device 13 is mounted on the right end of the pneumatic rotating device 6, and the drill rod 4, the pneumatic rotating device 6, and the slitting device 13 are all coaxially arranged;

[0048] In this structure, a flexible tool with a rotating adaptive whipping surface radius increasing structure performs a rotational whipping impact on the coal body layer, and converts the rotational kinetic energy into torque for the cutting device through the high-pressure gas pressure energy, thereby driving the cutting device to operate. The high-pressure gas pressure energy and the auxiliary release of pressure energy are fully utilized to make the gas pressure in the working surface where the flexible tool 1 and the flexible tool 2 are located higher, and mechanical fracturing is mainly used, supplemented by gas pressure fracturing. At the same time, the sticking rate of coal blocks and coal powder in the flexible tool 1 and the flexible tool 2 is reduced, and the flexibility of the coal breaking, pressure relief and permeability enhancement operation, the convenience of implementation, the cutting efficiency and the cutting strength are improved.

[0049] In this embodiment, the pneumatic rotating device 6 includes:

[0050] A cylindrical housing 7, the left end of which is engaged and fixed with a thread corresponding to the top end of the drill rod 4;

[0051] The drainage block frame 8 comprises a hemispherical shell one-way cone cap 81, wherein the left portion of the hemispherical shell one-way cone cap 81 is a hemispherical shell structure, and the right portion thereof is a cone structure, and drainage strips 82 arranged in a circumferential manner and axially fixedly laid on the outside of the hemispherical shell one-way cone cap 81 and whose upper ends are fixed to the inner shell wall of the cylindrical shell 7, wherein the left portion of the drainage strips 82 is a flat plate, and the right portion thereof is an arc-shaped plate structure;

[0052] The rotating module 20 is coaxially connected to the right part of the one-way cone cap 81 of the hemispherical shell;

[0053] This structure is mainly used for, firstly, reducing the diameter of the airflow cavity by the one-way cone cap of the hemispherical shell for the high-pressure gas that is about to enter and drive the rotating module to twist, that is, increasing the gas flow rate in the outer ring cavity away from the axis, helping to enhance the impact force of the rotating module and increase the rotation speed; secondly, pre-guiding the flow direction of the high-pressure gas that is about to enter and drive the rotating module to twist by the drainage block frame, further improving the efficiency of the starting and acceleration process of the rotating module and the steering controllability.

[0054] In this embodiment, the rotation module 20 includes:

[0055] The first rotor 9 comprises a rotating shaft 91 whose left end is coaxially connected to the right part of the hemispherical shell one-way cone cap 81, and an arc-shaped guide vane 92 is arranged on the outer ring wall of the rotating shaft 91 near the left end and fixedly laid in a circular arrangement and axial direction;

[0056] The flow-correcting sleeve fan 11 comprises a bidirectional cone cap 111 which is sleeved on the outside of the rotating shaft 91 and is rotatably connected. The central annular outer wall of the bidirectional cone cap 111 is fixed with DC fan plates 112 which are arranged in a circumferential manner and whose upper end faces are fixed to the inner shell wall of the cylindrical shell 7;

[0057] The second rotor 10 comprises a rotating shaft cylinder 101 which is arranged at the right end of the bidirectional cone cap 111 and is sleeved outside the rotating shaft 91 and is rotatably connected. On the outer ring wall of the rotating shaft cylinder 101 at the left end, arc-shaped guide vanes 102 are arranged in a circle and fixedly laid in an axial direction.

[0058] This structure is mainly used to improve the effective utilization rate and relative conversion rate of high-pressure gas pressure energy into rotational kinetic energy. That is, the axial direction structure of the DC fan plate in the flow-correcting plate frame fan is set so that after the gas pressure energy is converted into rotational kinetic energy on the first rotor, the direction of the swirling gas is relatively straightened, and the second rotor is impacted again to cause it to rotate, thereby making full use of the gas pressure energy.

[0059] In this embodiment, the arc guide piece 1 92 and the arc guide piece 2 102 are arranged in a central symmetrical structure, and the number of the arc guide piece 1 92 and the arc guide piece 2 102 is arranged in a one-to-one correspondence, and the lower bending trend of the arc piece at the right end of the arc guide piece 1 92 and the upper bending trend of the arc guide piece 2 102 and the left end arc piece are tangent to each other and are both axially directed;

[0060] In this structure, through the structural setting of arc guide plate 1 and arc guide plate 2, they produce opposite rotation directions after being impacted by airflow successively, thereby prompting the cutting device to greatly improve the rubbing and breaking strength of the coal body, making the coal body broken into finer pieces, and through the structural setting of the interval spacing, the airflow circulation is smoother, thereby improving the efficiency of the airflow connection impact kinetic energy.

[0061] In this embodiment, the conical curved surface wall in the hemispherical shell one-way cone cap 81 is an inclined surface that is convex and inclined at 30°.

[0062] In this embodiment, the bidirectional cone cap 111 is symmetrically arranged on the left and right, and its left side structure is consistent with the right conical structure of the hemispherical shell unidirectional cone cap 81, thereby improving the smoothness of the gas flow direction change process, that is, the upstream expands outward and squeezes, and the downstream shrinks inward and speeds up.

[0063] In this embodiment, the cutting device 13 includes:

[0064] A bearing ring 21 is coaxially mounted on the right end of the cylindrical housing 7;

[0065] The adapter shaft cylinder 14 is sleeved on the outside of the rotating shaft cylinder 101 and fixedly connected, and its outer ring wall is embedded in the inner ring wall of the bearing ring 21 for rotational connection, and the inner ring wall of the cylinder is provided with an axially directed and circumferentially arranged air leakage cavity 141, and each group of the air leakage cavity 1 142 is provided with a radially outwardly directed air leakage cavity 2 142 at the right end, and a dust-proof and breathable net 143 is installed in each of the air leakage cavity 2 142, and the outer ring wall of the adapter shaft cylinder 14 near the right end is provided with threaded holes 16 arranged circumferentially;

[0066] The stud 18 is embedded in the threaded hole 16 for meshing connection;

[0067] A flexible tool 15, comprising whip rings 19, which are configured into multiple groups and are sequentially connected in a series to form a strip whip structure, with a slit blade 17 provided on the outer ring wall, and one end of each group of the strip whips is welded to the corresponding stud 18;

[0068] The flexible cutter 2 22 has the same structure as the flexible cutter 15 and is installed on the outer shaft ring wall at the right end of the rotating shaft 91 .

[0069] In this embodiment, the bending tendency of the upper arc plate at the left end of each group of the arc-shaped guide plate 92 is tangent to the bending tendency of the lower arc plate at the right end of the right part of each group of the drainage strips 82 and is at an angle of 30° to the axial direction. The spacing between the drainage ends of adjacent drainage strips 82, the spacing between the left inlet ends of adjacent arc-shaped guide plates 92, and the spacing between the right end of the corresponding drainage strip and the left end of the arc-shaped guide plate 1 are all relatively consistent.

[0070] In this structure, the structural design of the flexible tool 1 and the flexible tool 2 enables them to have flexible scalability, so that they can enter the predetermined coal seam pressure relief and permeability enhancement working face in a targeted manner, and then enable the strip whip to be close to the device shell due to the coal hole diameter in the initial stage, and its slit blade rubs against the hole wall to destroy the coal body. As the rotation time increases, the coal hole diameter at the designated position gradually increases, and the strip whip is whipped and impacted to break the coal. In addition, the whip ring connected to the string sleeve in the strip whip can be semi-automatically irregularly twisted and rubbed during the whipping process, which not only enhances the coal breaking strength, but also effectively protects the blade of the slit blade. Finally, the coal hole diameter reaches the predetermined diameter, further improving the pressure relief and permeability enhancement strength, accuracy and effect;

[0071] As the best embodiment, the length of flexible tool 2 is half of the length of flexible tool 1, so that flexible tool 2 is first circularized due to the centrifugal strength, so that it can cut the coal body in a gradient manner, thereby improving its coal breaking efficiency.

[0072] When implemented specifically, it includes the following steps:

[0073] S1: Connect the air compressor 1, the high-pressure air pipe 2 and the drilling rig 3, and connect the drill rod 4 with the pneumatic rotating device 6 and the cutting device 13;

[0074] S2: Adjust the angle of the drill rod 4 and align the cutting device 13 with the designated position of the coal body;

[0075] S3: Turn on the air compressor 1 to deliver high-pressure gas to the pneumatic rotating device 6 through the high-pressure gas pipe 2 and the drill pipe 4;

[0076] S4: the pneumatic rotating device 6 drives the slitting device 13 to rotate, and the slitting device 13 starts to drive the flexible cutter 15 and the flexible cutter 22 to rotate and break the coal. When the hole diameter reaches the hole depth, the air pressure is reduced, the slitting device stops rotating, and the flexible cutter 15 and the flexible cutter 22 lose the power to break the coal;

[0077] S5: Repeat steps S3-S4 until the entire drilling construction is completed;

[0078] S6: After the permeability enhancement of a coal hole is completed, the permeability enhancement equipment is exited and other drilling holes are prepared:

[0079] S7: Repeat steps S2-S6 until all the boreholes are depressurized and permeability enhanced.

[0080] The above description is only a preferred specific implementation manner of the invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the invention, which should be covered by the protection scope of the present invention.

Claims

1. A pneumatic flexible tool coal breaking, pressure relief and permeability enhancement device in soft coal seams, characterized by: It includes: A drilling rig, wherein a drill rod is installed inside, and the shaft of the drill rod is provided with a columnar airflow cavity, and the outer ring wall of the top end of the drill rod at the outermost end is provided with a partial thread; An air compressor pump, the output end of which is sealedly connected to the air flow cavity through a high-pressure air pipe; A pneumatic slitting device, comprising a pneumatic rotating device and a slitting device, wherein the left end of the pneumatic rotating device is mounted on the top end of a drill rod at the outermost end, the right end of the pneumatic rotating device is mounted with the slitting device, and the drill rod, the pneumatic rotating device and the slitting device are all coaxially arranged; The pneumatic rotating device comprises: A cylindrical housing, the left end of which is engaged and fixed with a thread corresponding to the top end of the drill rod; A drainage block frame, comprising a hemispherical shell one-way cone cap, wherein the left portion of the hemispherical shell one-way cone cap is a hemispherical shell structure, and the right portion thereof is a cone structure, and drainage strips arranged in a circumferential manner and axially fixedly laid on the outside of the hemispherical shell one-way cone cap and whose upper ends are fixed to the inner shell wall of the cylindrical shell, wherein the left portion of the drainage strips is a flat plate, and the right portion thereof is an arc-shaped plate structure; A rotating module is coaxially connected to the right part of the one-way cone cap of the hemispherical shell; The rotation module comprises: The first rotor comprises a rotating shaft whose left end is coaxially connected to the right part of the one-way cone cap of the hemispherical shell, and an arc-shaped guide vane 1 is arranged on the outer ring wall of the rotating shaft near the left end and fixedly laid in a circumferential manner and axially pointing thereto; The flow-correcting sleeve fan comprises a bidirectional cone cap which is sleeved on the outside of the rotating shaft and is rotatably connected, and DC fan plates arranged in a circumferential manner and whose upper end faces are all fixed to the inner shell wall of the cylindrical shell are fixed on the annular outer wall in the middle of the bidirectional cone cap; The second rotor comprises a rotating shaft cylinder which is arranged at the right end of the bidirectional cone cap and is sleeved outside the rotating shaft and rotatably connected. The rotating shaft cylinder has two arc-shaped guide vanes arranged in a circle and fixedly laid on the outer ring wall at the left end thereof and pointing axially.

2. The device for breaking coal, unloading pressure and increasing permeability by using pneumatic flexible cutters in soft coal seams according to claim 1, characterized in that: The arc guide plate 1 and the arc guide plate 2 are arranged in a centrally symmetrical structure, and the number of the arc guide plate 1 and the arc guide plate 2 are arranged in a one-to-one correspondence. The lower bending trend of the arc plate at the right end of the arc guide plate 1 and the upper bending trend of the arc plate at the left end of the arc guide plate 2 are tangent to each other and are both axially pointed.

3. The device for breaking coal, unloading pressure and increasing permeability by using pneumatic flexible cutters in soft coal seams according to claim 1, characterized in that: The conical curved surface wall in the hemispherical shell one-way cone cap is an inclined surface that is convex and inclined at 30 degrees.

4. The device for breaking coal, unloading pressure and increasing permeability by using pneumatic flexible cutters in soft coal seams according to claim 1, characterized in that: The bidirectional cone cap is symmetrically arranged on the left and right sides, and its left side structure is consistent with the right cone structure of the hemispherical shell unidirectional cone cap.

5. The device for breaking coal, unloading pressure and increasing permeability by using pneumatic flexible cutters in soft coal seams according to claim 1, characterized in that: The cutting device comprises: A bearing ring, coaxially mounted on the right end of the cylindrical housing; The adapter shaft cylinder is sleeved on the outside of the rotating shaft cylinder and fixedly connected, and its outer ring wall is embedded in the inner ring wall of the bearing ring for rotational connection, and the inner ring wall of the cylinder is provided with an axially directed and circumferentially arranged air leakage cavity 1, and each group of the air leakage cavity 1 is provided with a radially outwardly directed air leakage cavity 2 at the right end, and a dust-proof and breathable net is installed in each of the air leakage cavity 2, and the outer ring wall of the adapter shaft cylinder near the right end is provided with threaded holes arranged circumferentially; A stud, embedded in the threaded hole for meshing connection; Flexible tool 1, comprising whip rings, which are configured into multiple groups and are sequentially connected in a series to form a strip whip structure, with a slit blade provided on the outer ring wall, and one end of each group of the strip whips is welded to the corresponding stud; Flexible tool 2 has the same structure as flexible tool 1 and is installed on the outer shaft ring wall at the right end of the rotating shaft.

6. The device for breaking coal, unloading pressure and increasing permeability by using pneumatic flexible cutters in soft coal seams according to claim 1, characterized in that: The upper bending trend of the arc plate at the left end of each group of the arc-shaped guide plate is tangent to the lower bending trend of the arc plate at the right end of the corresponding group of drainage strips and forms an angle of 30° with the axial direction. The spacing between the drainage ends of adjacent drainage strips, the spacing between the left inlet ends of adjacent arc-shaped guide plates, and the spacing between the right end of the corresponding drainage strip and the left end of the arc-shaped guide plate are all relatively consistent.

7. A method for breaking coal with a pneumatic flexible tool to relieve pressure and increase permeability in a soft coal seam, using a device for breaking coal with a pneumatic flexible tool to relieve pressure and increase permeability in a soft coal seam according to any one of claims 1 to 6, characterized in that: It includes the following steps: S1: Connect the air compressor, high-pressure air pipe and drilling rig, and connect the drill rod to the pneumatic rotating device and cutting device; S2: Adjust the drill rod angle and align the cutting device with the designated position of the coal body; S3: Turn on the air compressor and deliver the high-pressure gas to the pneumatic rotating device through the high-pressure gas pipe and the drill pipe; S4: The pneumatic rotating device drives the slitting device to rotate, and the slitting device starts to drive the flexible cutter 1 and the flexible cutter 2 to rotate and break the coal. When the hole diameter reaches the hole depth, the air pressure is reduced, the slitting device stops rotating, and the flexible cutter 1 and the flexible cutter 2 lose the power to break the coal; S5: Repeat steps S3-S4 until the entire drilling construction is completed; S6: After the permeability enhancement of a coal hole is completed, the permeability enhancement equipment is exited and other drilling holes are prepared: S7: Repeat steps S2-S6 until all the boreholes are depressurized and permeability enhanced.

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