A device and method for fracturing coal body by carrying sand high-pressure air circulation blasting

Abstract

The present application relates to coal mining and coal seam gas penetration technology field, disclose a kind of device and method of sand-carrying high-pressure air circulation burst and crack coal body, including base;Automatic stamping assembly is arranged at the top of base, for providing high-pressure gas;Gas storage assembly is arranged at the top of base, is connected with automatic stamping assembly by connecting assembly;Gas pressure transmission assembly is arranged at the top of base, gas pressure transmission assembly is connected with gas storage assembly by venturi tube;Sand-carrying assembly is communicated with venturi tube, sand-carrying assembly is used to add support agent in high-pressure airflow in venturi tube;Wherein, venturi tube uses venturi effect to introduce support agent in sand-carrying assembly into high-pressure airflow to form sand-carrying gas-solid two-phase flow, gas pressure transmission assembly realizes circulation burst action using gas pressure change, so that sand-carrying gas-solid two-phase flow cracks coal body and sends support agent into fracture, the present application does not need to use water, applicable to low-permeability, water-deficient coal seam.

Description

Technical Field

[0001] This invention relates to the field of coal mining and coalbed methane permeability enhancement technology, and in particular to a device and method for fracturing coal seams by high-pressure air circulation carrying sand. Background Technology

[0002] Coalbed methane (CBM) is a gaseous resource associated with and coexisting with coal, primarily composed of methane, and belongs to the category of unconventional natural gas resources. To improve CBM extraction efficiency, coal seams are typically fractured to increase their permeability. Existing coal seam fracturing devices commonly employ methods such as hydraulic fracturing, loosening blasting, and hydraulic perforation. However, these methods consume significant amounts of water and may cause environmental pollution. Especially in underground coal mine operations, the waste of water resources and the potential dangers of hydraulic permeation enhancement limit the application of these methods.

[0003] Current technologies, such as dry ice storage devices, can assist in high-pressure water fracturing of coal seams, but they remain limited due to their over-reliance on water resources and their inapplicability to most coal mines. Furthermore, while existing high-pressure air fracturing technology avoids water consumption, it suffers from the following technical drawbacks: Fractures are prone to closure: Although simple gas-induced fracturing can form fractures, these fractures are prone to closure under the stress of the original rock, resulting in insufficient long-term conductivity. Lack of support function: Existing devices cannot effectively deliver proppant into the fracture, making it difficult to maintain the open state of the fracture; Low sand carrying efficiency: Traditional equipment struggles to achieve uniform mixing and stable delivery of high-pressure airflow and proppant; Poor cyclic impact effect: a single impact is unlikely to cause fatigue damage, and the cracking efficiency is limited.

[0004] Therefore, there is an urgent need for an alternative technology that does not rely on water resources, which can efficiently and safely induce coal seam fracturing and simultaneously achieve fracture support, thereby improving the extraction efficiency of coalbed methane. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for fracturing coal seams by high-pressure air circulation carrying sand, which aims to solve or improve at least one of the above-mentioned technical problems. It does not require water, is suitable for low-permeability and water-deficient coal seams, and can significantly improve the long-term conductivity of fractures and the efficiency of gas extraction.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides a device for fracturing coal seams by high-pressure air circulation carrying sand, comprising: Base; An automatic stamping assembly, located on top of the base, is used to provide high-pressure gas; An air storage assembly is disposed on the top of the base and is connected to the automatic stamping assembly via a connecting assembly; A pneumatic transmission assembly is disposed on the top of the base, and the pneumatic transmission assembly is connected to the air storage assembly via a venturi tube; A sand-carrying assembly is connected to the Venturi tube and is used to add proppant to the high-pressure gas flow in the Venturi tube. The Venturi tube utilizes the Venturi effect to introduce the proppant from the sand-carrying assembly into the high-pressure airflow to form a sand-carrying gas-solid two-phase flow. The pneumatic transmission assembly utilizes air pressure changes to achieve a cyclic bursting action, causing the sand-carrying gas-solid two-phase flow to fracture the coal body and deliver the proppant into the fractures.

[0007] Optionally, the automatic stamping assembly includes: The first column is fixedly installed on the top of the base; An automatic stamping box is fixedly installed on the top of the first column; A pressure gauge is installed on top of the automatic stamping box to monitor the air pressure in real time; The first pressure relief pipe is located at the top of the automatic stamping box and is used to release pressure. An air outlet pipe is located on one side of the automatic stamping box and is connected to the connecting assembly.

[0008] Optionally, the gas storage assembly includes: The second column is fixedly installed on the top of the base; The gas storage tank is fixedly installed on the top of the second column and connected to the Venturi tube; The second pressure relief pipe is located at the top of the gas storage tank; An air intake pipe is located on one side of the air storage tank and is connected to the connecting assembly; The switch valve is located on the air intake pipe.

[0009] Optionally, the connection component includes: The air guide pipe is respectively connected to the automatic stamping assembly and the air storage assembly; Sliding rings are fitted at both ends of the air guide tube and are used to adjust the connection position; The mounting block is fixedly fitted in the middle of the air guide tube; A reset spring is disposed between the sliding ring and the mounting block.

[0010] Optionally, the two ends of the air guide pipe are respectively connected to the automatic stamping assembly and the air storage assembly through tapered and inverted tapered pipes of appropriate size.

[0011] Optionally, the sand-carrying assembly includes: Sand storage tank is located above the venturi tube; A sand filter screen is installed inside the sand storage tank; A screw feeder is connected between the sand storage tank and the venturi tube.

[0012] Optionally, the pneumatic transmission assembly includes: The third column is fixedly installed on the top of the base; An L-tube is installed at the top of the third column, and the vertical section of the L-tube is connected to the Venturi tube. A gravity column is installed in the vertical section of the L-tube and can move up and down along the L-tube under air pressure. Piston rings are fixedly fitted in the middle of the gravity column for sealing and guiding; A dumbbell-shaped pipe is fixedly installed at the top of the gravity column by a vertical column; A placement box is provided in the transverse section of the L-tube and communicates with the L-tube. A negative magnetic square groove is provided inside the placement box, and a positive magnetic square block is magnetically engaged in the negative magnetic square groove. A square steel pipe is slidably fitted on the side wall of the L-tube, and the square steel pipe is connected to the positive square magnetic block; A tensile steel rope is connected at one end to the dumbbell-shaped pipe and at the other end to the square steel pipe.

[0013] Optionally, the base is provided with track pulleys at its bottom.

[0014] Optionally, the base has a stabilizing cavity inside, and a hydraulic cylinder is installed in the stabilizing cavity by bolts. A stabilizing plate is fixedly welded to the output shaft of the hydraulic cylinder, and a stabilizing hole is provided on the stabilizing plate. The device is stably parked by driving the stabilizing plate to move down to contact the ground through the hydraulic cylinder.

[0015] This invention also provides a method for fracturing coal seams by high-pressure air circulation carrying sand, comprising the following steps: Move the device to the designated working position and place it stably. The automatic stamping assembly is activated to generate high-pressure gas. The high-pressure gas enters the gas storage assembly through the connecting assembly. At the same time, the sand-carrying assembly is activated to send the proppant into the Venturi tube, and the sand-carrying gas-solid two-phase flow is formed by utilizing the Venturi effect. The sand-carrying gas-solid two-phase flow enters the pneumatic transmission component, which uses air pressure changes to realize cyclic explosive action, so that the sand-carrying gas-solid two-phase flow fracturing the coal body and delivering proppant into the fracture. After completing the work, shut down the automatic stamping assembly and sand-carrying assembly, release the pressure inside the gas storage assembly and the automatic stamping assembly, and disassemble the connecting components for maintenance.

[0016] This invention discloses the following technical effects: By introducing proppant into the high-pressure airflow through the Venturi effect, a two-phase flow carrying sand and solid is formed, achieving a synergistic effect of cyclic explosive fracturing and fracture support on the coal body. It requires no water and is suitable for low-permeability and water-deficient coal seams, avoiding excessive dependence on water resources and environmental pollution from hydraulic fracturing. The Venturi effect achieves uniform mixing of high-pressure airflow and proppant, delivering proppant into the fracture while fracturing, preventing fracture closure. High-frequency cyclic explosive fracturing is achieved using a pneumatic transmission component, causing fatigue damage to the coal body. The fracturing effect is better than a single impact. By adjusting the air pressure and sandblasting time, it can adapt to the mining needs of different coal seams. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the automatic stamping assembly structure of the present invention; Figure 3 This is a schematic diagram of the connection component structure of the present invention; Figure 4 This is a schematic diagram of the gas storage component and sand carrying component of the present invention; Figure 5 This is a schematic diagram of the pneumatic transmission assembly of the present invention.

[0018] In the picture: 1. Base; 6. Venturi tube; 8. Tapered tube; 9. Inverted tapered tube; 10. Track pulley; 11. Hydraulic cylinder; 12. Stabilizing plate; 13. Stabilizing hole; 2. Automatic stamping assembly; 21. First column; 22. Automatic stamping box; 23. Pressure display gauge; 24. First pressure relief pipe; 25. Air outlet pipe; 3. Connecting assembly; 31. Air guide tube; 32. Sliding ring; 33. Mounting block; 34. Return spring; 4. Gas storage assembly; 41. Second column; 42. Gas storage tank; 43. Second pressure relief pipe; 44. Air inlet pipe; 45. Switch valve; 5. Pneumatic transmission assembly; 51. Third column; 52. L-tube; 53. Gravity column; 54. Piston ring; 55. Dumbbell-shaped pipe; 56. Vertical column; 57. Placement box; 58. Positive square magnet; 59. Square steel pipe; 510. Tensile steel rope; 7. Sand carrying assembly; 71. Sand storage tank; 72. Sand filter screen; 73. Screw feeder. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Reference Figures 1 to 5 This invention provides a device for fracturing coal seams using high-pressure air circulation with sand-carrying components, comprising: a base 1; an automatic pressing component 2 disposed on top of the base 1 for providing high-pressure gas; a gas storage component 4 disposed on top of the base 1 and connected to the automatic pressing component 2 via a connecting component 3; a pneumatic transmission component 5 disposed on top of the base 1 and connected to the gas storage component 4 via a Venturi tube 6; and a sand-carrying component 7 connected to the Venturi tube 6, which is used to add proppant to the high-pressure airflow in the Venturi tube 6. The Venturi tube 6 utilizes the Venturi effect to introduce the proppant from the sand-carrying component 7 into the high-pressure airflow, forming a sand-carrying gas-solid two-phase flow. The pneumatic transmission component 5 utilizes pressure changes to achieve a cyclic fracturing action, causing the sand-carrying gas-solid two-phase flow to fracture the coal seam and deliver the proppant into the fractures.

[0022] The Venturi tube 6 utilizes the Venturi effect to draw proppant into the high-pressure gas flow without additional power, achieving self-aspiration formation of the gas-solid two-phase flow. It features a simple structure, low energy consumption, and high mixing uniformity. The pneumatic transmission component 5 utilizes gas pressure changes to achieve cyclic bursting, converting continuous gas pressure into periodic pulse impacts, forming a fatigue damage mechanism, and effectively improving fracturing efficiency. The sand-carrying gas-solid two-phase flow fractures the coal body and delivers proppant into the fracture, achieving integrated fracturing and propping. Proppant filling is completed instantly upon fracture formation, with uniform proppant distribution and significantly improved long-term fracture conductivity. Each functional unit is independently set on the base 1, facilitating fault location, individual maintenance, and rapid replacement.

[0023] In this embodiment, the automatic stamping assembly 2 includes: a first column 21, fixedly mounted on the top of the base 1; an automatic stamping box 22, fixedly mounted on the top of the first column 21; a pressure display gauge 23, mounted on the top of the automatic stamping box 22, for real-time monitoring of air pressure; a first pressure relief pipe 24, mounted on the top of the automatic stamping box 22, for releasing pressure; and an air outlet pipe 25, mounted on one side of the automatic stamping box 22, connected to the connecting assembly 3.

[0024] The first column 21 is fixedly installed, providing a stable support structure to ensure that the components do not shift or vibrate under high pressure. The pressure display 23 provides real-time monitoring and visualization, facilitating precise adjustment of the working pressure according to the coal seam characteristics and optimizing the fracturing effect. The first pressure relief pipe 24 releases pressure quickly in emergencies, ensuring the safety of equipment and personnel and complying with coal mine safety regulations. The gas outlet pipe 25 connects to the connecting components, featuring a standardized interface design that facilitates compatibility with gas storage components of different specifications.

[0025] In this embodiment, the gas storage assembly 4 includes: a second column 41, which is fixedly installed on the top of the base 1; a gas storage tank 42, which is fixedly installed on the top of the second column 41 and connected to the venturi tube 6; a second pressure relief pipe 43, which is installed on the top of the gas storage tank 42; an air inlet pipe 44, which is installed on one side of the gas storage tank 42 and connected to the connecting assembly 3; and a switch valve 45, which is installed on the air inlet pipe 44.

[0026] The second column 41 is fixedly installed, forming a double support structure with the first column to improve overall stability; the second pressure relief pipe 43 and the first pressure relief pipe form a double safety protection to ensure that the pressure in the gas storage tank is controllable; the switch valve 45 controls the air inlet pipe to achieve rapid cut-off of the air path, which is convenient for emergency shutdown and maintenance; the gas storage tank 42 is directly connected to the venturi tube to shorten the air path, reduce pressure loss, and increase the energy density of the sand-carrying airflow.

[0027] In this embodiment, the connecting component 3 includes: an air guide pipe 31, which is inserted into the automatic stamping component 2 and the air storage component 4 respectively; a sliding ring 32, which is sleeved on both ends of the air guide pipe 31 for adjusting the connection position; a mounting block 33, which is fixedly sleeved on the middle part of the air guide pipe 31; and a return spring 34, which is disposed between the sliding ring 32 and the mounting block 33.

[0028] The sliding ring 32 adjusts the connection position to improve assembly adaptability; the return spring 34 provides pre-tightening force through elastic connection to ensure connection sealing; the air duct 31's plug-in method enables quick assembly and disassembly, effectively shortening maintenance time.

[0029] In this embodiment, the two ends of the air guide tube 31 are respectively connected to the automatic stamping component 2 and the air storage component through a tapered tube 8 and an inverted tapered tube 9 of suitable size.

[0030] The conical sealing structure of the tapered tube 8 and the inverted tapered tube 9, which are matched in size, has a large contact area and better sealing performance than the planar seal. It is resistant to high pressure and does not leak. The plug-in fit has a good self-centering effect, low installation accuracy requirements, and is easy to connect quickly on site.

[0031] In this embodiment, the sand-carrying assembly 7 includes: a sand storage tank 71, disposed above the venturi tube 6; a sand filter screen 72, disposed inside the sand storage tank 71; and a screw feeder 73, connected between the sand storage tank 71 and the venturi tube 6.

[0032] A sand filter screen 72 is installed inside the sand storage tank 71 to filter impurities, prevent clogging of the venturi tube, and improve system reliability. A screw feeder 73 connects the sand storage tank 71 and the venturi tube 6 to precisely control the sand feed rate, realize stepless adjustment of the proppant flow rate, and adapt to different fracture size requirements. A sand storage tank 71 is installed above the venturi tube 6 to use gravity-assisted sand supply, reduce the load on the feeder, and reduce energy consumption.

[0033] In this embodiment, the pneumatic transmission assembly 5 includes: a third column 51, fixedly mounted on the top of the base 1; an L-tube 52, mounted on the top of the third column 51, with its vertical section connected to a Venturi tube 6; a gravity column 53, mounted within the vertical section of the L-tube 52, capable of moving up and down along the L-tube 52 under pneumatic pressure; a piston ring 54, fixedly sleeved in the middle of the gravity column 53 for sealing and guiding; a dumbbell-shaped pipe 55, fixedly mounted on the top of the gravity column 53 via a vertical column 56; a placement box 57, mounted on the horizontal section of the L-tube 52 and connected to the L-tube 52, the placement box 57 containing a negative magnetic square groove, in which a positive magnetic square magnet 58 is magnetically engaged; a square steel pipe 59, slidably mounted on the side wall of the L-tube 52, connected to the positive magnetic square magnet 58; and a tensile steel rope 510, one end connected to the dumbbell-shaped pipe 55 and the other end connected to the square steel pipe 59.

[0034] The vertical section of L-tube 52 connects to Venturi tube 6 to form a vertical airflow channel. Automatic reset is achieved using the weight of gravity column 53, eliminating the need for an additional reset mechanism. Gravity column 53 moves up and down along L-tube 52, converting pressure energy into mechanical energy, and then into impact energy, resulting in high energy conversion efficiency. Piston ring 54 seals and guides, ensuring airtightness, reducing pressure loss, and guaranteeing smooth, unobstructed movement of gravity column 53. Dumbbell-shaped pipe 55 is fixed by vertical column 56, expanding the connection area with the tensile steel rope, dispersing stress, and improving fatigue resistance. Service life; the negative magnetic square groove and the positive square magnetic block 58 are magnetically matched, and the magnetic force serves as an energy storage-release control mechanism, which does not require electrical control components and meets the explosion-proof requirements of coal mines. The magnitude of the magnetic force can be adjusted by the specifications of the magnetic block to control the release threshold; the square steel pipe 59 slides on the side wall of the L-tube 52 and moves synchronously with the positive square magnetic block 58, serving as the switch actuator for the exhaust port; the tensile steel rope 510 connects the dumbbell-shaped pipe 55 and the square steel pipe 59, providing flexible transmission, adapting to the space constraints at the bend of the L-tube 52, and achieving high transmission efficiency.

[0035] Furthermore, the vertical section of L-tube 52 has a split structure, which is detachably connected to a threaded pipe via a detachable threaded port. The dumbbell-shaped pipe 55 is set at the top of the threaded pipe, and the radius of the vertical column 56 is smaller than the opening radius of the threaded pipe. The detachable threaded port and the threaded pipe facilitate the separation of the pipe body of the vertical section of L-tube 52, allowing the gravity column 53 and piston ring 54 to leave L-tube 52, which facilitates its maintenance and replacement and improves its service life.

[0036] In this embodiment, a track pulley 10 is provided at the bottom of the base 1.

[0037] The base 1 is equipped with a track pulley 10 at the bottom, which facilitates the movement of the device on underground or ground tracks, adapting to the narrow working environment of coal mine roadways, making it easy to move and flexible to turn.

[0038] In this embodiment, a stabilizing cavity is provided inside the base 1, and a hydraulic cylinder 11 is installed in the stabilizing cavity by bolts. A stabilizing plate 12 is fixedly welded to the output shaft of the hydraulic cylinder 11, and a stabilizing hole 13 is provided on the stabilizing plate 12. The device is stably parked by driving the stabilizing plate 12 to move down to contact the ground through the hydraulic cylinder 11.

[0039] A hydraulic cylinder 11 is installed inside the stabilizing chamber. The concealed design does not increase the external profile size and protects the hydraulic components from collisions. The output shaft of the hydraulic cylinder 11 is fixedly welded to the stabilizing plate 12, which increases the contact area with the ground, reduces the ground pressure, and adapts to soft base plates. Stabilizing holes 13 are opened on the stabilizing plate 12, which can be used to insert ground anchors or pins to achieve rigid fixation and prevent backlash displacement during operation. The hydraulically driven stabilizing plate 12 moves down to contact the ground, with smooth lifting and high support force. After stopping, the automatic pressing component operates without vibration, improving the cracking accuracy.

[0040] This invention also provides a method for fracturing coal seams using high-pressure air circulation with sand-carrying components, comprising the following steps: moving the device to a designated working position and stabilizing it; activating the automatic pressing component to generate high-pressure gas, which enters the gas storage component 4 through the connecting component 3, while simultaneously activating the sand-carrying component 7 to deliver proppant into the Venturi tube 6, forming a sand-carrying gas-solid two-phase flow using the Venturi effect; the sand-carrying gas-solid two-phase flow entering the pneumatic transmission component 5, which uses pressure changes to achieve cyclic fracturing action, causing the sand-carrying gas-solid two-phase flow to fracture the coal seam and deliver proppant into the fractures; after completing the work, shutting down the automatic pressing component 2 and the sand-carrying component 7, releasing the pressure in the gas storage component 4 and the automatic pressing component 2, and disassembling the connecting component 3 for maintenance.

[0041] Specifically: The device is moved to the designated working position using the track pulleys 10. Next, the hydraulic cylinder 11 is opened, which moves the stabilizing plate 12 until it contacts the ground, at which point the hydraulic cylinder 11 is closed. At this point, the stabilizing plate 12, through the stabilizing holes 13, stabilizes the device, ensuring that the equipment can be placed securely.

[0042] Then, select a suitable sand filter screen 72 and open the screw feeder 73 to allow sand particles to be added into the venturi tube 6. Start the automatic pressurization box 22, and the gas is transmitted to the gas storage tank 42 through the air guide pipe 31 and enters the L-tube 52 through the venturi tube 6. As the air pressure continues to increase, the gravity column 53 begins to rise, driving the piston ring 54, the vertical column 56, and the dumbbell-shaped pipe 55 to move upward. During this process, the dumbbell-shaped pipe 55 pulls the tensile steel rope 510 upward, which in turn drives the square steel pipe 59 and the positive square magnetic block 58 to move upward.

[0043] Due to the magnetic force between the positive square magnetic block 58 and the negative magnetic square groove, this upward force ensures that gas is instantly discharged from the outlet of L-tube 52. The area of ​​the positive square magnetic block 58 is larger than that of the square steel pipe 59, ensuring that it will not be pulled out of L-tube 52 by the tensile steel rope 510. At the same time, the weight of the gravity column 53 and the positive square magnetic block 58 ensures that they can be reset. This process is repeated, forming a continuous cycle, successfully inducing fatigue damage to the coal body. This method avoids the excessive consumption of water resources in traditional hydraulic fracturing methods by fracturing the coal body with gas. Pressure changes are observed in real time on the pressure display 23, and the operator can adjust the pressure in the automatic pressure box 22 to select the appropriate gas pressure according to different coal types, thereby more effectively controlling the degree of fatigue damage to the coal body. This operation is not only efficient but also highly practical.

[0044] After completing the work, first close the screw feeder 73 to stop the addition of sand particles; close the automatic pressurizing box 22 to stop the gas supply. Turn the switch valve 45 to close the valve of the air inlet pipe 44, cutting off the gas flow into the system. Release the pressure in the air storage box 42: open the second pressure relief pipe 43 on the air storage box 42 to release the remaining gas in the air storage box. Open the first pressure relief pipe 24 on the automatic pressurizing box 22 to further release the gas in the box and ensure the internal pressure balance of the device. Finally, by adjusting the sliding ring 32, drive the inverted cone pipe 9 to move to the middle of the guide pipe 31, and the inverted cone pipe 9 is removed from the cone pipe 8, so the connecting assembly 3 can be easily disassembled.

[0045] To further disassemble the device, the top short tube of L-tube 52 can be easily separated from the bottom tube body via a detachable threaded port and connecting threaded pipe, thereby separating the gravity column 53 and piston ring 54 from L-tube 52. This operation simplifies the equipment maintenance and replacement process and effectively extends the service life of the equipment.

[0046] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0047] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for fracturing coal seams by high-pressure air circulation carrying sand, characterized in that, include: Base (1); An automatic stamping assembly (2) is disposed on top of the base (1) for providing high-pressure gas; An air storage assembly (4) is disposed on the top of the base (1) and connected to the automatic stamping assembly (2) via a connecting assembly (3); A pneumatic transmission assembly (5) is disposed on the top of the base (1), and the pneumatic transmission assembly (5) is connected to the gas storage assembly (4) through a venturi tube (6); The sand-carrying assembly (7) is connected to the Venturi tube (6) and is used to add proppant to the high-pressure gas flow in the Venturi tube (6); The Venturi tube (6) uses the Venturi effect to introduce the proppant in the sand-carrying component (7) into the high-pressure airflow to form a sand-carrying gas-solid two-phase flow. The pneumatic transmission component (5) uses the change of air pressure to realize the cyclic bursting action, so that the sand-carrying gas-solid two-phase flow can crack the coal body and send the proppant into the crack.

2. The device for fracturing coal seams by high-pressure air circulation carrying sand according to claim 1, characterized in that, The automatic stamping assembly (2) includes: The first column (21) is fixedly installed on the top of the base (1); An automatic stamping box (22) is fixedly installed on the top of the first column (21); A pressure display gauge (23) is installed on top of the automatic press box (22) for real-time monitoring of air pressure; The first pressure relief pipe (24) is located on the top of the automatic press box (22) for releasing pressure; An air outlet pipe (25) is located on one side of the automatic stamping box (22) and connected to the connecting assembly (3).

3. The device for fracturing coal seams by high-pressure air circulation carrying sand according to claim 1, characterized in that, The gas storage component (4) includes: The second column (41) is fixedly installed on the top of the base (1); The gas storage tank (42) is fixedly installed on the top of the second column (41) and connected to the venturi tube (6); The second pressure relief pipe (43) is installed on the top of the gas storage tank (42); An air inlet pipe (44) is disposed on one side of the air storage tank (42) and connected to the connecting assembly (3); A switch valve (45) is provided on the air inlet pipe (44).

4. The device for fracturing coal seams by high-pressure air circulation with sand as described in claim 1, characterized in that, The connection component (3) includes: The air duct (31) is connected to the automatic stamping assembly (2) and the air storage assembly (4) respectively; Sliding rings (32) are fitted at both ends of the air guide tube (31) for adjusting the connection position; The mounting block (33) is fixedly sleeved in the middle of the air guide tube (31); A reset spring (34) is disposed between the sliding ring (32) and the mounting block (33).

5. The device for fracturing coal seams by high-pressure air circulation with sand as described in claim 4, characterized in that, The two ends of the air guide pipe (31) are respectively connected to the automatic stamping component (2) and the air storage component through a tapered pipe (8) and an inverted tapered pipe (9) of suitable size.

6. The device for fracturing coal seams by high-pressure air circulation with sand as described in claim 1, characterized in that, The sand-carrying assembly (7) includes: A sand storage tank (71) is located above the venturi tube (6); A sand filter screen (72) is installed inside the sand storage tank (71); A screw feeder (73) is connected between the sand storage tank (71) and the venturi tube (6).

7. The device for fracturing coal seams by high-pressure air circulation with sand as described in claim 1, characterized in that, The pneumatic transmission assembly (5) includes: The third column (51) is fixedly installed on the top of the base (1); L-tube (52) is installed on the top of the third column (51), and the vertical section of the L-tube (52) is connected to the Venturi tube (6); The gravity column (53) is installed in the vertical section of the L-tube (52) and can move up and down along the L-tube (52) under air pressure; Piston ring (54) is fixedly sleeved in the middle of the gravity column (53) for sealing and guiding; A dumbbell-shaped pipe (55) is fixedly installed on the top of the gravity column (53) by a vertical column (56); Placement box (57) is set in the transverse section of the L tube (52) and communicates with the L tube (52). The placement box (57) is provided with a negative magnetic square groove, and a positive magnetic square block (58) is magnetically engaged in the negative magnetic square groove. A square steel pipe (59) is slidably fitted on the side wall of the L-tube (52), and the square steel pipe (59) is connected to the positive square magnetic block (58); A tensile steel rope (510) is connected at one end to the dumbbell-shaped pipe (55) and at the other end to the square steel pipe (59).

8. The device for fracturing coal seams by high-pressure air circulation with sand as described in claim 1, characterized in that, The base (1) is provided with a track pulley (10) at its bottom.

9. The device for fracturing coal seams by high-pressure air circulation carrying sand according to claim 1, characterized in that, The base (1) has a stabilizing cavity inside, and a hydraulic cylinder (11) is installed in the stabilizing cavity by bolts. A stabilizing plate (12) is fixedly welded on the output shaft of the hydraulic cylinder (11). A stabilizing hole (13) is opened on the stabilizing plate (12). The device is stably parked by driving the stabilizing plate (12) to move down to contact the ground through the hydraulic cylinder (11).

10. A method for fracturing coal seams using high-pressure air circulation with sand, based on the apparatus for fracturing coal seams using high-pressure air circulation with sand according to any one of claims 1-9, characterized in that, Includes the following steps: Move the device to the designated working position and place it stably. The automatic stamping assembly is activated to generate high-pressure gas. The high-pressure gas enters the gas storage assembly (4) through the connecting assembly (3). At the same time, the sand-carrying assembly (7) is activated to send the proppant into the Venturi tube (6), and the sand-carrying gas-solid two-phase flow is formed by utilizing the Venturi effect. The sand-carrying gas-solid two-phase flow enters the pneumatic transmission component (5). The pneumatic transmission component (5) uses the change of air pressure to realize the cyclic bursting action, so that the sand-carrying gas-solid two-phase flow can crack the coal body and deliver the proppant into the crack. After completing the work, shut down the automatic stamping assembly (2) and the sand-carrying assembly (7), release the pressure inside the gas storage assembly (4) and the automatic stamping assembly (2), and disassemble the connecting assembly (3) for maintenance.

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