Air bag type memory metal net sleeve hole collapse prevention device and method for coal seam extraction drilling

Abstract

The invention relates to a coal seam extraction drilling air bag type memory metal net cover hole collapse prevention device and method, the device comprises an I-type air bag net cover installation unit body, a plurality of II-type air bag net cover installation unit bodies and an inflator pump, an exhaust pipeline is provided with an exhaust control valve, a hole wall is supported through a memory metal net cover, and the air bag net cover installation unit body and the inflator pump are arranged in the hole wall; the memory metal net sleeves can be matched with drill holes with different hole diameters in a self-adaptive mode and can be repeatedly used, the configuration number of the memory metal net sleeves can be greatly reduced, and therefore the processing cost of hole collapse prevention is further reduced; the installation of the memory metal net sleeve is directly controlled by the expansion of the air bag, so that the memory metal net sleeve can be quickly unfolded and reliably contacted with the hole wall; the removal of the memory metal net sleeve is directly controlled by temperature control gas, so that the memory metal net sleeve retracts to an initial state at the recovery temperature and is separated from the hole wall; the mounting and dismounting process of the memory metal net cover has the advantages of being simple, efficient and easy to operate, and the construction efficiency can be further improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal mine safety mining and gas extraction, in particular relates to a gas bag type memory metal mesh sleeve anti-caving device and method for coal seam extraction drilling. BACKGROUND

[0002] In the process of coal mining, gas extraction is the core link to ensure safety production and efficient use of resources. As the key channel for gas extraction, the stability of coal seam extraction drilling directly determines the efficiency of gas extraction and construction safety. However, when facing soft and broken coal seams, the caving problem of coal seam extraction drilling seriously restricts the progress of gas control.

[0003] At present, the anti-caving technology of coal seam extraction drilling mainly includes mud protection, casing protection, chemical grouting and screen pipe protection.

[0004] For the mud protection method, it balances the pressure of the hole wall by injecting mud protection, forms a mud skin support layer on the surface of the hole wall, and prevents caving. However, in high permeability and broken coal seams, the mud protection is easy to lose, and the residual mud protection is also easy to block the drilling, which affects the effect of gas extraction, and the hole cleaning process is also complex.

[0005] For the casing protection method, it supports the hole wall by lowering the casing. Although the supporting effect of the casing is better than that of the mud protection, the cost of the supporting casing is high, and the casing diameter needs to be accurately matched with the drilling diameter. Especially in long distance drilling, the consumption of the casing is very large, which not only further increases the cost of anti-caving treatment, but also has the problem of complicated operation of installation and pulling out of the casing, which seriously reduces the construction efficiency, and the inner diameter of the casing also limits the installation of extraction equipment and the upper limit value of extraction flow.

[0006] For the chemical grouting method, the hole wall is reinforced by injecting chemical grout into the surrounding rock. However, the grouting material not only has the problem of high price, but also has certain toxicity, so there is a risk of environmental pollution, and the grouting pressure and time control are also difficult, which is easy to cause uneven diffusion of the grout and even block the drilling.

[0007] For the screen pipe protection method, the hole wall is supported by the suspension wings connected by torsion springs. However, the supporting force of this supporting method is limited, and the wings are easy to retract when the drilling deforms, which leads to the failure of the hole wall support. Although the wings are replaced by elastic foot mechanisms in another technology, the elastic foot and the hole wall are in point contact state, and there is a large area that is not in contact with the hole wall, so the area that is not in contact with the hole wall is still easy to collapse, and it is difficult to ensure the stability of the anti-caving. SUMMARY

[0008] In response to the problems existing in the prior art, the present invention provides a coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device and method, which supports the hole wall by using the memory metal mesh sleeve. The memory metal mesh sleeve can adaptively match the boreholes of different apertures and can be reused, which can greatly reduce the configuration quantity of the memory metal mesh sleeve, thereby further reducing the processing cost of the anti-collapse hole; the installation of the memory metal mesh sleeve is directly controlled by the expansion of the airbag, so that the memory metal mesh sleeve can be quickly unfolded and maintain reliable contact with the hole wall; the removal of the memory metal mesh sleeve is directly controlled by the temperature-controlled gas, so that the memory metal mesh sleeve can shrink to the initial state at the recovery temperature and break away from the hole wall; the installation and removal process of the memory metal mesh sleeve is simple, efficient and easy to operate, which can further improve the construction efficiency.

[0009] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a coal seam extraction drilling airbag type memory metal mesh anti-collapse device, including a Type I airbag mesh installation unit, a Type II airbag mesh installation unit and an air pump; the number of the Type I airbag mesh installation unit is one; the number of the Type II airbag mesh installation unit is multiple; the Type I airbag mesh installation unit is located on the bottom side of the borehole; the Type II airbag mesh installation unit is located in the borehole and is sequentially connected in series with the Type I airbag mesh installation unit on the bottom side of the hole; the air pump is connected to the Type II airbag mesh installation unit located on the borehole mouth side through an air guide pipe.

[0010] The I-type airbag mesh installation unit includes an I-type center tube, an I-type airbag and a memory metal mesh; one end of the I-type center tube is closed by a sealing plug, and the other end of the I-type center tube is provided with a first adapter internal thread, and a number of ventilation holes are evenly opened in the middle of the tube body of the I-type center tube, and the ventilation holes are connected with the inner cavity of the I-type center tube; the I-type airbag is coaxially sleeved on the outside of the I-type center tube, and the two end openings of the I-type airbag are sealed and connected with the outer surface of the tube body of the I-type center tube; the ventilation hole is located on the inside of the I-type airbag; a first ventilation joint is provided at one end of the I-type airbag, and the first ventilation joint and the first adapter internal thread are distributed on the same side; the memory metal mesh is coaxially sleeved on the outside of the I-type airbag.

[0011] The Type II airbag mesh installation unit includes a Type II center tube, a Type II airbag and a memory metal mesh; one end of the Type II center tube is provided with a transfer external thread, and the other end of the Type II center tube is provided with a second transfer internal thread; the Type II airbag is coaxially sleeved on the outside of the Type II center tube, and the two end openings of the Type II airbag are sealed and connected to the outer surface of the tube body of the Type II center tube; a second ventilation joint is provided at one end of the Type II airbag, and the second ventilation joint and the second transfer internal thread are distributed on the same side; a third ventilation joint is provided at the other end of the Type II airbag, and the third ventilation joint and the transfer external thread are distributed on the same side; the memory metal mesh is coaxially sleeved on the outside of the Type II airbag.

[0012] The first transition internal thread on the type I center tube is sealed and threadedly matched with the transition external thread on the type II center tube; the adjacent type II center tubes are sealed and threadedly matched with the transition external thread and the second transition internal thread.

[0013] The first ventilation connector on the type I airbag is connected to the third ventilation connector on the type II airbag through a pressure regulating valve; the second ventilation connector and the third ventilation connector between adjacent type II airbags are also connected through a pressure regulating valve.

[0014] In the direction from the bottom end of the borehole to the orifice end, the opening setting pressure values ​​of each pressure regulating valve increase step by step, the opening setting pressure value of the pressure regulating valve located at the bottom end of the borehole is the lowest, and the opening setting pressure value of the pressure regulating valve located at the orifice end of the borehole is the highest.

[0015] The air guide pipeline is connected to an exhaust pipeline, and an exhaust control valve is provided on the exhaust pipeline.

[0016] A joint sealing cover is installed on the second vent joint of the II-type airbag at the end of the drilled hole.

[0017] Flame retardant paint is sprayed on the surface of the memory metal mesh sleeve.

[0018] A method for preventing hole collapse of a coal seam extraction drilling hole using an air bag type memory metal mesh sleeve, which adopts the coal seam extraction drilling hole air bag type memory metal mesh sleeve anti-hole collapse device, comprises the following steps: Step 1: Prepare a drilling rig, select a hollow drill rod that matches the diameter and depth of the drill hole, and determine the number of Type II airbag mesh installation units based on the depth of the drill hole; Step 2: Assemble the selected number of Type II airbag net installation units in series with the only Type I airbag net installation unit, and simultaneously complete the installation of the pressure regulating valve and the joint sealing cover to form an airbag net installation assembly; Step 3: Move the drill rig to the selected drilling location, connect the hollow drill rod to the drill rig, and then drive the hollow drill rod into the coal seam according to the set depth; Step 4: After the hollow drill rod is driven into the coal seam to the set depth, disconnect the drilling rig from the hollow drill rod, then clean out all the debris inside the hollow drill rod and temporarily leave the hollow drill rod in the borehole; Step 5: Insert the previously assembled airbag mesh installation assembly into the hollow drill rod until the I-type airbag mesh installation unit rests against the bottom surface of the drill hole; Step 6: Connect the air pump to the Type II center tube on the Type II airbag mesh installation unit located on the side of the drill hole through the air guide pipe, and adjust the exhaust control valve on the exhaust pipe to the closed state. Step 7: Pull the hollow drill rod backward to remove it from the borehole at a uniform speed until the hollow drill rod completely removes the obstruction of the I-type airbag mesh installation unit, and then stop removing the hollow drill rod; Step 8: Start the air pump to allow air to flow through the air guide pipe, the Type II central tubes on all Type II airbag mesh installation units, the Type I central tubes on the Type I airbag mesh installation units, and the vents on the Type I central tubes in sequence, and then fill the Type I airbag on the Type I airbag mesh installation unit. As air is continuously filled in, the Type I airbag gradually expands, thereby simultaneously expanding the outer memory metal mesh until the memory metal mesh is completely in contact with the drilled hole wall, and then the inflation is paused; Step 9: Continue to pull the hollow drill rod backward, so that the hollow drill rod is pulled out of the borehole at a uniform speed, until the hollow drill rod completely removes the obstruction of the first type II airbag net sleeve installation unit on the bottom side of the borehole, and then stop pulling out the hollow drill rod; Step 10: Resume inflation. Since the Type I airbag cannot continue to expand, the pressure inside the Type I airbag will increase rapidly. When the pressure increases to the opening set pressure value of the first pressure regulating valve at the bottom of the drilled hole, the first pressure regulating valve at the bottom of the drilled hole is opened, and the air inside the Type I airbag begins to flow into the Type II airbag on the first Type II airbag mesh installation unit at the bottom of the drilled hole. The Type II airbag gradually expands, and then the outer memory metal mesh is simultaneously stretched open until the memory metal mesh is completely in contact with the drilled hole wall, and then inflation is suspended. Step 11: Repeat the operation of pulling out the hollow drill rod and inflating the airbags, so that the Type II airbags on the remaining Type II airbag mesh installation units are gradually expanded, thereby gradually expanding the memory metal mesh, until the last memory metal mesh on the side of the drill hole is fully expanded and contacts the drill hole wall. The process of supporting and fixing the drill hole wall by the memory metal mesh is completed, and the hollow drill rod is completely pulled out of the drill hole, and then the inflation is stopped; Step 12: Open the exhaust control valve. Under the action of the rebound reset force of the airbags, the air in the Type I airbag and all the Type II airbags will eventually be squeezed out through the exhaust pipe. At the same time, as the Type I airbag and all the Type II airbags rebound and reset, all the airbags are separated from all the memory metal mesh sleeves. Then, the remaining part of the airbag mesh sleeve installation assembly with the memory metal mesh sleeve separated is pulled out from the drilled hole. Only the memory metal mesh sleeve in the expanded state left in the drilled hole supports the drilled hole wall to prevent the hole from collapsing. Step 13: After all gas extraction operations are completed in the drilling, temperature-controlled gas at a set temperature is introduced into the borehole to make the memory metal mesh sleeve reach the recovery temperature. At the recovery temperature, the memory metal mesh sleeve quickly recovers from the expanded state to the initial retracted state, thereby realizing the separation of the memory metal mesh sleeve from the borehole wall. Finally, the recovered memory metal mesh sleeve is removed from the borehole to realize the reuse of the memory metal mesh sleeve.

[0019] Beneficial effects of the present invention: The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device and method of the present invention supports the hole wall by using the memory metal mesh sleeve. The memory metal mesh sleeve can be adaptively matched with boreholes of different apertures and can be reused, which can greatly reduce the configuration quantity of the memory metal mesh sleeve, thereby further reducing the processing cost of the anti-collapse hole; the installation of the memory metal mesh sleeve is directly controlled by the expansion of the airbag, so that the memory metal mesh sleeve can be quickly unfolded and maintain reliable contact with the hole wall; the removal of the memory metal mesh sleeve is directly controlled by the temperature-controlled gas, so that the memory metal mesh sleeve shrinks to the initial state at the recovery temperature and loses contact with the hole wall; the installation and removal process of the memory metal mesh sleeve is simple, efficient and easy to operate, which can further improve construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural schematic diagram of a coal seam extraction drilling airbag type memory metal mesh sleeve anti-hole collapse device of the present invention; Figure 2 This is a schematic cross-sectional view of the I-type airbag mesh installation unit of the present invention; Figure 3 This is a structural diagram of the I-type airbag net installation unit of the present invention (initial state); Figure 4 This is a schematic structural diagram of the I-type airbag mesh installation unit of the present invention (inflated state); Figure 5 This is a schematic cross-sectional view of a Type II airbag mesh installation unit of the present invention; Figure 6 Schematic diagram of the structure of the Type II airbag net installation unit of the present invention (initial state); Figure 7Schematic diagram of the structure of the Type II airbag net installation unit of the present invention (expanded state); Figure 8 This is a schematic diagram of the step-by-step expansion and installation process of a coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device of the present invention.

[0021] In the figure, 1—Type I airbag mesh installation unit, 2—Type II airbag mesh installation unit, 3—inflator, 4—drill hole, 5—air guide pipe, 6—Type I center tube, 7—Type I airbag, 8—memory metal mesh, 9—sealing plug, 10—first adapter internal thread, 11—vent, 12—first ventilation connector, 13—Type II center tube, 14—Type II airbag, 15—adapter external thread, 16—second adapter internal thread, 17—second ventilation connector, 18—third ventilation connector, 19—pressure regulating valve, 20—exhaust pipe, 21—exhaust control valve, 22—connector sealing cover. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figures 1 to 8 As shown, a coal seam extraction drilling airbag type memory metal mesh anti-collapse device includes a type I airbag mesh installation unit 1, a type II airbag mesh installation unit 2 and an air pump 3; the number of the type I airbag mesh installation unit 1 is one; the number of the type II airbag mesh installation unit 2 is multiple; the type I airbag mesh installation unit 1 is located at the bottom side of the borehole 4; the type II airbag mesh installation unit 2 is located in the borehole 4 and is sequentially connected in series with the type I airbag mesh installation unit 1 on the bottom side; the air pump 3 is connected to the type II airbag mesh installation unit 2 located on the orifice side of the borehole 4 through an air guide pipe 5.

[0024] The I-type airbag mesh sleeve installation unit 1 includes an I-type center tube 6, an I-type airbag 7 and a memory metal mesh sleeve 8; one end of the I-type center tube 6 is closed by a sealing plug 9, and the other end of the I-type center tube 6 is provided with a first adapter internal thread 10, and a number of ventilation holes 11 are evenly opened in the middle of the tube body of the I-type center tube 6, and the ventilation holes 11 are connected to the inner cavity of the I-type center tube 6; the I-type airbag 7 is coaxially sleeved on the outside of the I-type center tube 6, and the two end openings of the I-type airbag 7 are sealed and connected to the outer surface of the tube body of the I-type center tube 6; the ventilation holes 11 are located on the inside of the I-type airbag 7; a first ventilation joint 12 is provided at one end of the I-type airbag 7, and the first ventilation joint 12 is distributed on the same side as the first adapter internal thread 10; the memory metal mesh sleeve 8 is coaxially sleeved on the outside of the I-type airbag 7.

[0025] The II-type airbag mesh sleeve installation unit 2 includes a II-type center tube 13, a II-type airbag 14 and a memory metal mesh sleeve 8; one end of the tube opening of the II-type center tube 13 is provided with a switching external thread 15, and the other end of the tube opening of the II-type center tube 13 is provided with a second switching internal thread 16; the II-type airbag 14 is coaxially sleeved on the outside of the II-type center tube 13, and the two end openings of the II-type airbag 14 are sealed and connected to the outer surface of the tube body of the II-type center tube 13; a second ventilation joint 17 is provided at one end of the II-type airbag 14, and the second ventilation joint 17 and the second switching internal thread 16 are distributed on the same side; a third ventilation joint 18 is provided at the other end of the II-type airbag 14, and the third ventilation joint 18 and the switching external thread 15 are distributed on the same side; the memory metal mesh sleeve 8 is coaxially sleeved on the outside of the II-type airbag 14.

[0026] The first transition internal thread 10 on the type I center tube 6 is sealed and threadedly matched with the transition external thread 15 on the type II center tube 13; adjacent type II center tubes 13 are sealed and threadedly matched with the transition external thread 15 and the second transition internal thread 16.

[0027] The first vent connector 12 on the type I airbag 7 is connected to the third vent connector 18 on the type II airbag 14 through a pressure regulating valve 19; the second vent connector 17 and the third vent connector 18 between adjacent type II airbags 14 are also connected through a pressure regulating valve 19.

[0028] In the direction from the bottom end of the borehole 4 to the orifice end, the opening setting pressure values ​​of each pressure regulating valve 19 increase step by step. The opening setting pressure value of the pressure regulating valve 19 located at the bottom end of the borehole 4 is the lowest, and the opening setting pressure value of the pressure regulating valve 19 located at the orifice end of the borehole 4 is the highest.

[0029] An exhaust pipe 20 is connected to the air guide pipe 5 , and an exhaust control valve 21 is provided on the exhaust pipe 20 .

[0030] A joint sealing cover 22 is installed on the second vent joint 17 of the II-type airbag 14 at the orifice end of the drilled hole 4 .

[0031] The surface of the memory metal mesh sleeve 8 is sprayed with flame retardant paint to prevent the memory metal mesh sleeve 8 from directly contacting and rubbing with the inner surface of the hollow drill rod to generate electric sparks, thereby improving the safety during the anti-collapse operation.

[0032] A method for preventing hole collapse of a coal seam extraction drilling hole using an air bag type memory metal mesh sleeve, which adopts the coal seam extraction drilling hole air bag type memory metal mesh sleeve anti-hole collapse device, comprises the following steps: Step 1: Prepare a drilling machine, select a hollow drill rod that matches the diameter and depth of the drill hole 4, and determine the number of type II airbag mesh installation units 2 according to the depth of the drill hole 4; Step 2: Assemble a selected number of Type II airbag net installation units 2 in series with a single Type I airbag net installation unit 1, and simultaneously install the pressure regulating valve 19 and the joint sealing cover 22 to form an airbag net installation assembly. In this embodiment, there are two Type II airbag net installation units 2 and two pressure regulating valves 19. Step 3: Move the drill rig to the selected drilling location, connect the hollow drill rod to the drill rig, and then drive the hollow drill rod into the coal seam according to the set depth; Step 4: After the hollow drill rod is driven into the coal seam to a set depth, disconnect the drilling rig from the hollow drill rod, and then clean all debris inside the hollow drill rod, leaving the hollow drill rod temporarily in the borehole 4; Step 5: Insert the previously assembled airbag mesh installation assembly into the hollow drill rod until the I-type airbag mesh installation unit body 1 rests against the bottom surface of the drill hole 4; Step 6: The air pump 3 is sealed and connected to the Type II center tube 13 on the Type II airbag mesh installation unit 2 located on the side of the borehole 4 through the air guide pipe 5, and the exhaust control valve 21 on the exhaust pipe 20 is adjusted to the closed state; Step 7: Pull the hollow drill rod backward to remove the drill hole 4 at a uniform speed until the hollow drill rod completely removes the obstruction of the I-type airbag mesh installation unit 1, and then stop removing the hollow drill rod; Step 8: Start the air pump 3, so that air flows through the air guide pipe 5, the Type II central tube 13 on all Type II airbag mesh installation units 2, the Type I central tube 6 on the Type I airbag mesh installation unit 1, and the vent 11 on the Type I central tube 6, and then fills the Type I airbag 7 on the Type I airbag mesh installation unit 1. As air is continuously filled, the Type I airbag 7 gradually expands, and then simultaneously expands the outer memory metal mesh 8 until the memory metal mesh 8 is completely in contact with the wall of the drill hole 4, and then the inflation is paused; Step 9: Continue to pull the hollow drill rod backward, so that the hollow drill rod is pulled out of the borehole 4 at a uniform speed, until the hollow drill rod completely removes the obstruction of the first II-type airbag net sleeve installation unit 2 on the bottom side of the borehole 4, and then stop pulling out the hollow drill rod; Step 10: Resume inflation. Since the Type I airbag 7 cannot continue to expand, the pressure inside the Type I airbag 7 will increase rapidly. When the pressure increases to the opening set pressure value of the first pressure regulating valve 19 at the bottom side of the drill hole 4, the first pressure regulating valve 19 at the bottom side of the drill hole 4 is opened, and the air inside the Type I airbag 7 begins to flow into the Type II airbag 14 on the first Type II airbag mesh installation unit 2 at the bottom side of the drill hole 4. The Type II airbag 14 gradually expands, and then synchronously expands the outer memory metal mesh 8 until the memory metal mesh 8 is completely in contact with the wall of the drill hole 4, and then inflation is suspended. Step 11: Repeat the pulling and inflating operations of the hollow drill rod and the airbags to gradually expand the Type II airbags 14 on the remaining Type II airbag mesh installation units 2, thereby gradually expanding the memory metal mesh sleeves 8, until the last memory metal mesh sleeve 8 on the side of the borehole 4 is fully expanded and contacts the wall of the borehole 4. The process of supporting and fixing the wall of the borehole 4 by the memory metal mesh sleeves 8 is completed, and the hollow drill rod is completely pulled out of the borehole 4, and then the inflation is stopped; Step 12: Open the exhaust control valve 21. Under the action of the airbag rebound reset force, the air in the type I airbag 7 and all the type II airbags 14 will eventually be squeezed out through the exhaust pipe 20. At the same time, as the type I airbag 7 and all the type II airbags 14 rebound and reset, all the airbags are separated from all the memory metal mesh sleeves 8. Then, the remaining part of the airbag mesh sleeve installation assembly with the memory metal mesh sleeve 8 separated is pulled out from the borehole 4. Only the memory metal mesh sleeve 8 in the expanded state left in the borehole 4 supports the wall of the borehole 4 to prevent the hole from collapsing. Step 13: After all gas extraction operations are completed in the borehole 4, temperature-controlled gas at a set temperature is introduced into the borehole 4 to make the memory metal mesh sleeve 8 reach the recovery temperature. At the recovery temperature, the memory metal mesh sleeve 8 quickly recovers from the expanded state to the initial retracted state, thereby realizing the separation of the memory metal mesh sleeve 8 from the wall of the borehole 4. Finally, the recovered memory metal mesh sleeve 8 is removed from the borehole 4 to realize the reuse of the memory metal mesh sleeve 8.

[0033] The solutions in the embodiments are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications that do not depart from the scope of protection of the present invention are included in the scope of protection of the present invention.

Claims

1. A coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device, characterized by: It includes a type I airbag mesh installation unit, a type II airbag mesh installation unit and an air pump; the number of the type I airbag mesh installation unit is one; the number of the type II airbag mesh installation unit is multiple; the type I airbag mesh installation unit is located at the bottom side of the drilled hole; the type II airbag mesh installation unit is located in the drilled hole and is sequentially connected in series with the type I airbag mesh installation unit at the bottom side of the hole; the air pump is connected to the type II airbag mesh installation unit located at the hole mouth side through an air guide pipe.

2. The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device according to claim 1, characterized in that: The I-type airbag mesh installation unit includes an I-type center tube, an I-type airbag and a memory metal mesh; one end of the I-type center tube is closed by a sealing plug, and the other end of the I-type center tube is provided with a first adapter internal thread, and a number of ventilation holes are evenly opened in the middle of the tube body of the I-type center tube, and the ventilation holes are connected with the inner cavity of the I-type center tube; the I-type airbag is coaxially sleeved on the outside of the I-type center tube, and the two end openings of the I-type airbag are sealed and connected with the outer surface of the tube body of the I-type center tube; the ventilation hole is located on the inside of the I-type airbag; a first ventilation joint is provided at one end of the I-type airbag, and the first ventilation joint and the first adapter internal thread are distributed on the same side; the memory metal mesh is coaxially sleeved on the outside of the I-type airbag.

3. The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device according to claim 2, characterized in that: The Type II airbag mesh installation unit includes a Type II center tube, a Type II airbag and a memory metal mesh; one end of the Type II center tube is provided with a transfer external thread, and the other end of the Type II center tube is provided with a second transfer internal thread; the Type II airbag is coaxially sleeved on the outside of the Type II center tube, and the two end openings of the Type II airbag are sealed and connected to the outer surface of the tube body of the Type II center tube; a second ventilation joint is provided at one end of the Type II airbag, and the second ventilation joint and the second transfer internal thread are distributed on the same side; a third ventilation joint is provided at the other end of the Type II airbag, and the third ventilation joint and the transfer external thread are distributed on the same side; the memory metal mesh is coaxially sleeved on the outside of the Type II airbag.

4. The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device according to claim 3, characterized in that: The first transition internal thread on the type I center tube is sealed and threadedly matched with the transition external thread on the type II center tube; the adjacent type II center tubes are sealed and threadedly matched with the transition external thread and the second transition internal thread.

5. The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device according to claim 3, characterized in that: The first ventilation connector on the type I airbag is connected to the third ventilation connector on the type II airbag through a pressure regulating valve; the second ventilation connector and the third ventilation connector between adjacent type II airbags are also connected through a pressure regulating valve.

6. The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device according to claim 5, characterized in that: In the direction from the bottom end of the borehole to the orifice end, the opening setting pressure values ​​of each pressure regulating valve increase step by step, the opening setting pressure value of the pressure regulating valve located at the bottom end of the borehole is the lowest, and the opening setting pressure value of the pressure regulating valve located at the orifice end of the borehole is the highest.

7. The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device according to claim 6, characterized in that: The air guide pipeline is connected to an exhaust pipeline, and an exhaust control valve is provided on the exhaust pipeline.

8. The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device according to claim 7, characterized in that: A joint sealing cover is installed on the second vent joint of the II-type airbag at the end of the drilled hole.

9. The coal seam extraction drilling airbag type memory metal mesh sleeve anti-collapse device according to claim 1, characterized in that: Flame retardant paint is sprayed on the surface of the memory metal mesh sleeve.

10. A method for preventing hole collapse by using an airbag-type memory metal mesh sleeve for coal seam extraction drilling, which uses the airbag-type memory metal mesh sleeve for preventing hole collapse by using the coal seam extraction drilling device according to claim 8, characterized in that: The steps include: Step 1: Prepare a drilling rig, select a hollow drill rod that matches the diameter and depth of the drill hole, and determine the number of Type II airbag mesh installation units based on the depth of the drill hole; Step 2: Assemble the selected number of Type II airbag net installation units in series with the only Type I airbag net installation unit, and simultaneously complete the installation of the pressure regulating valve and the joint sealing cover to form an airbag net installation assembly; Step 3: Move the drill rig to the selected drilling location, connect the hollow drill rod to the drill rig, and then drive the hollow drill rod into the coal seam according to the set depth; Step 4: After the hollow drill rod is driven into the coal seam to the set depth, disconnect the drilling rig from the hollow drill rod, then clean out all the debris inside the hollow drill rod and temporarily leave the hollow drill rod in the borehole; Step 5: Insert the previously assembled airbag mesh installation assembly into the hollow drill rod until the I-type airbag mesh installation unit rests against the bottom surface of the drill hole; Step 6: Connect the air pump to the Type II center tube on the Type II airbag mesh installation unit located on the side of the drill hole through the air guide pipe, and adjust the exhaust control valve on the exhaust pipe to the closed state. Step 7: Pull the hollow drill rod backward to remove it from the borehole at a uniform speed until the hollow drill rod completely removes the obstruction of the I-type airbag mesh installation unit, and then stop removing the hollow drill rod; Step 8: Start the air pump to allow air to flow through the air guide pipe, the Type II central tubes on all Type II airbag mesh installation units, the Type I central tubes on the Type I airbag mesh installation units, and the vents on the Type I central tubes in sequence, and then fill the Type I airbag on the Type I airbag mesh installation unit. As air is continuously filled in, the Type I airbag gradually expands, thereby simultaneously expanding the outer memory metal mesh until the memory metal mesh is completely in contact with the drilled hole wall, and then the inflation is paused; Step 9: Continue to pull the hollow drill rod backward, so that the hollow drill rod is pulled out of the borehole at a uniform speed, until the hollow drill rod completely removes the obstruction of the first type II airbag net sleeve installation unit on the bottom side of the borehole, and then stop pulling out the hollow drill rod; Step 10: Resume inflation. Since the Type I airbag cannot continue to expand, the pressure inside the Type I airbag will increase rapidly. When the pressure increases to the opening set pressure value of the first pressure regulating valve at the bottom of the drilled hole, the first pressure regulating valve at the bottom of the drilled hole is opened, and the air inside the Type I airbag begins to flow into the Type II airbag on the first Type II airbag mesh installation unit at the bottom of the drilled hole. The Type II airbag gradually expands, and then the outer memory metal mesh is simultaneously stretched open until the memory metal mesh is completely in contact with the drilled hole wall, and then inflation is suspended. Step 11: Repeat the operation of pulling out the hollow drill rod and inflating the airbags, so that the Type II airbags on the remaining Type II airbag mesh installation units are gradually expanded, thereby gradually expanding the memory metal mesh, until the last memory metal mesh on the side of the drill hole is fully expanded and contacts the drill hole wall. The process of supporting and fixing the drill hole wall by the memory metal mesh is completed, and the hollow drill rod is completely pulled out of the drill hole, and then the inflation is stopped; Step 12: Open the exhaust control valve. Under the action of the rebound reset force of the airbags, the air in the Type I airbag and all the Type II airbags will eventually be squeezed out through the exhaust pipe. At the same time, as the Type I airbag and all the Type II airbags rebound and reset, all the airbags are separated from all the memory metal mesh sleeves. Then, the remaining part of the airbag mesh sleeve installation assembly with the memory metal mesh sleeve separated is pulled out from the drilled hole. Only the memory metal mesh sleeve in the expanded state left in the drilled hole supports the drilled hole wall to prevent the hole from collapsing. Step 13: After all gas extraction operations are completed in the drilling, temperature-controlled gas at a set temperature is introduced into the borehole to make the memory metal mesh sleeve reach the recovery temperature. At the recovery temperature, the memory metal mesh sleeve quickly recovers from the expanded state to the initial retracted state, thereby realizing the separation of the memory metal mesh sleeve from the borehole wall. Finally, the recovered memory metal mesh sleeve is removed from the borehole to realize the reuse of the memory metal mesh sleeve.

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