Coal mine gas extraction double-injection hole sealing device

Abstract

The utility model discloses a coal mine gas extraction double-injection hole sealing device which comprises a first main bag body, a second main bag body and a first pipeline, and the first pipeline provides slurry for the first main bag body and the second main bag body to enable the first main bag body and the second main bag body to expand and make contact with the hole wall. The device further comprises a first auxiliary bag body, a second auxiliary bag body and a second pipeline, the first auxiliary bag body is attached to the first main bag body and is close to the hole opening, and the second auxiliary bag body is attached to the second main bag body and is close to the hole bottom. The second pipeline provides slurry for the first auxiliary bag body and the second auxiliary bag body so that the first auxiliary bag body and the second auxiliary bag body can expand to make contact with the hole wall, and a first explosion valve and an exhaust part are arranged on the second pipeline and located at the plugging section. And one end of the second pipeline is respectively connected with the second grouting pipe, the exhaust pipe and the slurry discharge pipe in a switching manner. According to the utility model, secondary plugging can be carried out on the plugging section of the drill hole, the problems of plugging effect reduction and air leakage caused by the influence of mining are avoided, gas extraction is guaranteed, and the compressive strength of solidified slurry can be improved.

Description

Technical Field

[0001] This utility model relates to borehole sealing technology, belonging to the field of gas extraction, and specifically to a dual-injection sealing device for coal mine gas extraction. Background Technology

[0002] Gas extraction is one of the necessary tasks before coal mining in gas-filled mines. It involves using specialized equipment and pipelines to extract or discharge gas from coal seams, rock strata, and goaf areas in order to reduce the gas concentration in the mine airflow, improve the safety of mine production, and utilize gas resources to increase economic benefits.

[0003] The quality of borehole plugging directly affects the quality of gas extraction. The current borehole plugging method often adopts the "two plugs and one injection" method. This method significantly improves the gas extraction concentration and efficiency through double plugging and grouting reinforcement. Specifically, plugs are set at both ends of the target section of the borehole to form a plugging section. Cement grout, polymer materials and other slurries are then injected into the plugging section under high pressure to fill the cracks around the borehole and block the gas leakage channel.

[0004] This method is simple and easy to operate, but it has the following problems: 1. When the grout enters the sealing section, the gas in the sealing section cannot be discharged in time (generally it is passively discharged under pressure). The grout entering the sealing section will result in a certain amount of gas in the grout. This gas will affect the solidification quality of the grout, making the grout not solidified. That is, more pores will be formed inside the grout. After long-term extraction, the solidified grout will deform and loosen, resulting in reduced sealing performance. 2. After the sealing is completed for a period of time, the stress of the coal seam rock mass changes due to the influence of surrounding mining operations. The internal shrinkage or creep phenomenon is likely to occur. At this time, cracks will expand in the sealing section (grouting section) and around the borehole, allowing gas to enter the borehole from the cracks or for gas in the borehole to overflow from the cracks. The sealing effect will decrease, and even air leakage may occur, which will seriously affect the gas extraction effect. Summary of the Invention

[0005] The purpose of this utility model is to provide a dual-injection sealing device for coal mine gas extraction, which can perform secondary sealing of the sealing section of the borehole, avoid the decrease in sealing effect and air leakage caused by mining, ensure gas extraction, and improve the compressive strength of the solidified slurry.

[0006] To achieve the above objectives, the dual-injection sealing device for gas drainage in this coal mine includes:

[0007] The first main capsule and the second main capsule are arranged at intervals along the length of the borehole, with the first main capsule near the borehole opening and the second main capsule forming a sealing section;

[0008] The first conduit connects and passes through the first main chamber and the second main chamber, providing slurry to cause the corresponding main chamber to expand and contact the borehole wall; a first burst valve is provided on the first conduit at the plugging section;

[0009] The first and second auxiliary sluices are both transported through the second pipe to expand and contact the borehole wall. The first auxiliary sluice is attached to the first main sluice and close to the borehole opening, while the second auxiliary sluice is attached to the second main sluice and close to the bottom of the borehole.

[0010] The second pipe connects and passes through the first and second sub-bladders, providing slurry to cause the corresponding sub-bladders to expand and contact the borehole wall; a first rupture valve and an exhaust device are provided on the second pipe at the plugging section;

[0011] The first pipe is connected to the first grouting pipe; one end of the second pipe is connected to the second grouting pipe, the vent pipe, and the grout discharge pipe respectively.

[0012] In some examples of this utility model, one end of the second pipe is connected to one end of the four-way valve;

[0013] The other ends of the four-way valve are connected to the second grouting pipe, the vent pipe, and the grout discharge pipe, respectively.

[0014] The exhaust pipe is connected to the negative pressure assembly.

[0015] In some examples of this utility model, the first rupture valve is provided with a cylinder covered by an end-side seal.

[0016] The cylinder is equipped with multiple damping holes.

[0017] In some examples of this utility model, the first rupture valve is provided with a cylinder covered by an end-side seal.

[0018] The cylinder is provided with a through hole that connects its inner and outer sides;

[0019] The sealing element, which is subjected to elastic force, moves within the through hole. When the pressure inside the cylinder decreases, the sealing element closes the through hole; when the pressure inside the cylinder increases, the sealing element opens the through hole.

[0020] In some examples of this utility model, a third pipe is sleeved on the outside of the second pipe;

[0021] A passage is formed between the third and second pipelines;

[0022] One end of the channel is connected to a telescopic bladder located in the sealing section, and the other end extends to the outside of the borehole and is connected to the inflation source and negative pressure source via a medium pipe.

[0023] In some examples of this utility model, the telescopic bladder is a pleated structure folded along the length of the borehole, and the volume of the telescopic bladder first increases along the length of the borehole and then increases radially.

[0024] In some examples of this utility model, both the first main capsule and the second main capsule are provided with a first one-way valve for slurry to flow unidirectionally to the corresponding main capsule.

[0025] Both the first and second sub-capsule bodies are equipped with a second one-way valve that allows slurry to flow in one direction to the corresponding sub-capsule body.

[0026] In some examples of this utility model, the exhaust component is a branch pipe or a slurry-blocking filter screen;

[0027] The branch pipe is connected to the second pipe and has multiple through holes; the slurry-blocking filter screen is wrapped around the outside of the through holes.

[0028] In some examples of this utility model, the second pipeline is provided with a third check valve for the medium to flow from the blocking section to the second pipeline.

[0029] Compared with existing technologies, this coal mine gas extraction dual-injection sealing device has a first and a second auxiliary bladder, and a second pipeline connects to and passes through the first and second auxiliary bladders. When cracks will appear in the sealing section and around the borehole after a period of time following the completion of the first grouting, the first and second auxiliary bladders can fit against the borehole wall for secondary sealing. The grout fills the sealing section and the cracks around the borehole, and the cracks are sealed through secondary grouting, avoiding a decrease in sealing effect and air leakage, thus ensuring the gas extraction effect.

[0030] Because the second pipe is equipped with an exhaust device and the exhaust pipe is connected to the negative pressure component, the gas in the sealing section can be actively discharged and kept in a negative pressure state before grouting in the sealing section. After the grout enters the sealing section, the presence of gas can be reduced, the compressive strength of the cured grout can be improved, and the deformation and loosening of the cured grout can be avoided, which would reduce the sealing performance. In addition, the second pipe is equipped with a closed cylinder, which can reduce the impact of the grout on the sealing section.

[0031] Since a channel is formed between the third and second pipes, the expansion of the telescopic bladder after inflation will compress the space of the sealing section, and the gas in the sealing section will be squeezed out while maintaining the corresponding pressure. When the slurry enters the sealing section, the telescopic bladder can be squeezed by the slurry to expel the gas, or actively expel the gas, so as to avoid the increase of fluid accumulation in the borehole or the shrinkage and deformation of the borehole rock mass under negative pressure, which would damage the structure of the sealing section. It is suitable for different rock masses. Attached Figure Description

[0032] Figure 1 This is a front view of the present invention during a single grouting process;

[0033] Figure 2 This is a front view of the secondary grouting process of this utility model;

[0034] Figure 3 This is a front view of the telescopic bladder of this utility model in operation;

[0035] Figure 4 This is a partially enlarged view of the buffering mechanism using the cylindrical body in this utility model;

[0036] Figure 5 This is a partially enlarged view of the buffering mechanism achieved by the elastic sealing element in this utility model;

[0037] Figure 6 This is a partially enlarged view of the four-way valve connection assembly in this utility model;

[0038] Figure 7 This is a partially enlarged view of the exhaust component in this utility model;

[0039] In the diagram: 10. Extraction tube;

[0040] 21. First pipe; 22. First main bladder; 23. Second main bladder; 241. First burst valve; 242. Cylinder; 243. Sealing element; 244. Elastic element; 245. Ring; 246. Damping orifice.

[0041] 31. Second pipe; 32. First auxiliary bladder; 33. Second auxiliary bladder; 34. Second burst valve; 35. Exhaust device; 351. Branch pipe; 352. Third check valve; 353. Slurry filter screen.

[0042] 40. Four-way valve;

[0043] 51. Third pipe; 52. Telescopic bladder;

[0044] 61. First grouting pipe; 62. Second grouting pipe; 63. Exhaust pipe; 64. Grout discharge pipe; 65. Medium pipe. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0046] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0047] like Figure 1 , Figure 2 , Figure 6 As shown, the dual-injection sealing device for gas drainage in this coal mine includes:

[0048] The first main capsule 22 and the second main capsule 23 are arranged at intervals along the length of the borehole, and the first main capsule 22 near the borehole opening and the second main capsule 23 form a sealing section;

[0049] The first auxiliary capsule 32 and the second auxiliary capsule 33 are both transported with slurry through the second pipe 31 and then expand to contact the borehole wall. The first auxiliary capsule 32 is attached to the first main capsule 22 and close to the borehole opening, and the second auxiliary capsule 33 is attached to the second main capsule 23 and close to the bottom of the borehole.

[0050] The first pipe 21 connects and passes through the first main bladder 22 and the second main bladder 23, providing slurry to cause the corresponding main bladder to expand and contact the borehole wall; a first burst valve 241 is provided on the first pipe 21 at the sealing section;

[0051] The second pipe 31 connects and passes through the first sub-bladder 32 and the second sub-bladder 33, providing slurry to cause the corresponding sub-bladder to expand and contact the borehole wall; the second pipe 31 is equipped with a first burst valve 241 and an exhaust component 35 at the plugging section.

[0052] The first pipe 21 is connected to the first grouting pipe 61; one end of the second pipe 31 is switched to be connected to the second grouting pipe 62, the exhaust pipe 63, and the grout discharge pipe 64 respectively.

[0053] Specifically, the first pipe 21, the first main bladder 22, and the second main bladder 23 form the main grouting structure. One end of the first pipe 21 is connected to the grouting source through the first grouting pipe 61, and the other end passes through and connects the first main bladder 22 and the second main bladder 23. In the initial state, the first main bladder 22 and the second main bladder 23 are small in volume, and after the volume increases, they can contact the hole wall to form a seal.

[0054] The second pipe 31, the first auxiliary bladder 32, and the second auxiliary bladder 33 form a secondary grouting structure. One end of the second pipe 31 passes through and connects the first auxiliary bladder 32 and the second auxiliary bladder 33. In the initial state, the first auxiliary bladder 32 and the second auxiliary bladder 33 are small in volume. After the volume increases, they can contact the borehole wall to form a seal. The first auxiliary bladder 32 is attached to the first main bladder 22, and the second auxiliary bladder 33 is attached to the second main bladder 23. That is, the first auxiliary bladder 32 and the first main bladder 22 are an integral structure with a sealed gap in the middle, and the second auxiliary bladder 33 and the second main bladder 23 are an integral structure with a sealed gap in the middle.

[0055] One end of the extraction pipe 10 passes through the first auxiliary capsule 32, the first main capsule 22, and the second main capsule 23. The first auxiliary capsule 32 is located at the bottom of the borehole and is used for gas extraction.

[0056] During the first grouting of the dual-injection sealing device for gas extraction in this coal mine, the grout enters the first main bladder 22 and the second main bladder 23 through the first pipe 21, which increases the volume of the corresponding main bladder and makes it fit against the borehole wall. At this time, a sealing section is formed between the first main bladder 22 and the second main bladder 23.

[0057] Grouting continues into the first pipe 21. When the grouting pressure in the first pipe 21 exceeds the opening pressure of the first burst valve 241, the first burst valve 241 opens. The burst pressure can be 1.5MPa. It is noted that the first burst valve 241 is activated to quickly release pressure when the grouting pressure exceeds a set threshold. This is the existing structure. Then the grout enters the sealing section until the grouting pressure reaches the set range, completing one grouting cycle.

[0058] The grout gradually fills the sealing section and the cracks around the borehole. The air in the sealing section is discharged from the exhaust pipe 35 on the second pipe 31 to avoid the gas from mixing into the grout and affecting the grout curing quality. When liquid appears in the grout discharge pipe 64 of the second pipe 31 and the grouting pressure remains stable, such as 2MPa, the first grouting is completed.

[0059] After a period of time following the completion of the borehole sealing, cracks will appear in the sealing section and around the borehole due to the influence of surrounding mining operations. These cracks will reduce the sealing performance of the sealing section, the first main bladder 22, and the second main bladder 23 during the first grouting, and new cracks will appear around the borehole. Therefore, the grout enters the first auxiliary bladder 32 and the second auxiliary bladder 33 through the second pipe 31. The first auxiliary bladder 32 will conform to the first main bladder 22 and increase in volume, and the second auxiliary bladder 33 will conform to the second main bladder 23 and increase in volume, so that the corresponding auxiliary bladders conform to the borehole wall for secondary sealing, so as to prevent gas from overflowing or entering from the cracks around the borehole between the corresponding main bladders and the borehole. When the grouting pressure in the second pipe 31 exceeds the opening pressure of the second rupture valve 34, the second rupture valve 34 opens, and the grout fills the sealing section and the cracks around the borehole until the grouting pressure reaches the set range, thus completing the secondary grouting.

[0060] As explained, during secondary grouting, the sealing section is already sealed with grout, and the cracks in the sealing section and the borehole are irregular and their arrangement is uncertain. Therefore, the grouting pressure requirement is greater. During secondary grouting, on the one hand, venting is not required, and on the other hand, the grout can enter the sealing section from the venting device 35.

[0061] In some examples of this utility model, such as Figure 1 , Figure 6 As shown, one end of the second pipe 31 is connected to one end of the four-way valve 40;

[0062] The other ends of the four-way valve 40 are respectively connected to the second grouting pipe 62, the vent pipe 63, and the grout discharge pipe 64;

[0063] Exhaust pipe 63 is connected to the negative pressure assembly;

[0064] Specifically, the four-way valve 40 is used for switching between the second pipe 31 and the second grouting pipe 62, the exhaust pipe 63, and the grout discharge pipe 64. The four passages of the four-way valve 40 are equipped with opening and closing valves. For example, the opening and closing valve on the second pipe 31 is in the open state, the opening and closing valve on the grout discharge pipe 64 is in the open state, and the opening and closing valves on the second grouting pipe 62 and the exhaust pipe 63 are in the closed state. At this time, it is used for grout discharge treatment.

[0065] Due to the influence of the drilling angle and the position of the venting device 35, after the first blasting valve 241 is opened, the slurry enters the sealing section. However, it is difficult to expel the gas as much as possible through the passive venting method, especially when the slurry is above the venting device 35. This will reduce the compressive strength of the solidified slurry and make it unable to withstand the deformation of the surrounding rock under large negative pressure conditions.

[0066] Before grouting, the exhaust pipe 63 is connected to the second pipe 31 through the four-way valve 40. When the first main bladder 22 and the second main bladder 23 expand to form a closed sealing section, the negative pressure component is activated, which can actively discharge the gas in the sealing section, and the sealing section is in a negative pressure state. Then the exhaust pipe 63 is closed, and after the first burst valve 241 is opened, the grout enters the sealing section. When the grouting pressure reaches the set range, the grout discharge pipe 64 is connected to the second pipe 31 for grout discharge.

[0067] This example uses negative pressure on the sealing section, which not only improves the compressive strength of the solidified slurry, but also expands the gas flow driving pressure difference, increases the extraction rate, and reduces gas accumulation in the borehole.

[0068] It should be noted that after venting the blocked section, the vented gas needs to be treated to prevent partial gas leakage.

[0069] When the sealing section is under negative pressure and the first rupture valve 241 is opened, the impact of the slurry on the sealing section is greater, which can easily damage the inner wall of the borehole and the extraction pipe 10 that passes through it.

[0070] As an example of slurry buffering, such as Figure 4 As shown, the first rupture valve 241 is provided with a cylinder 242 covered with an end-side seal on the outside;

[0071] Multiple damping holes 246 are provided on the cylinder body 242;

[0072] Specifically, when the first burst valve 241 is opened, the high-pressure slurry will be buffered through the damping hole 246 on the cylinder 242. This buffering can respond instantly without delay, but it cannot adapt to dynamic needs and is more suitable for the stable impact of the slurry after the first burst valve 241 is opened.

[0073] As another embodiment, as shown in the figure, Figure 5 As shown, the first rupture valve 241 is provided with a cylinder 242 covered with an end-side seal on the outside;

[0074] The cylinder 242 is provided with a through hole that communicates with its inner and outer sides;

[0075] The sealing element 243, which is subjected to elastic force, moves to be located in the through hole. When the pressure inside the cylinder 242 decreases, the sealing element 243 closes the through hole; when the pressure inside the cylinder 242 increases, the sealing element 243 opens the through hole.

[0076] Specifically, the end of the cylinder 242 and the sealing section can be sealed by the ring 245; the ring 245 is provided with a through hole with a double-step structure, the elastic element 244 and the sealing element 243 are located in the through hole with a larger inner diameter, one end of the elastic element 244 is limited, and the other end acts on the sealing element 243, so that the sealing element 243 is sealed by elastic force at the end with a smaller inner diameter of the through hole; the sealing element 243 can be a ball or a rod smaller than the through hole with a larger inner diameter, so as to facilitate movement and compression of the elastic element 244;

[0077] In this example, the sealing element 243 is configured to buffer the grout. Specifically, the cylinder 242 is wrapped around the outside of the first burst valve 241 and forms a transition cavity between it and the first pipe 21. Before grouting, the sealing element 243 is closed by the elastic force of the through hole. When the first burst valve 241 is opened, the internal pressure of the cylinder 242 increases, causing the sealing element 243 to move elastically to buffer the grout and open the through hole, allowing the grout to enter the closed section from the cylinder 242. This buffering mainly relies on the spring stiffness and preload, which can perform dynamic buffering and is more suitable for the transient impact of the opening of the first burst valve 241.

[0078] In some examples of this utility model, such as Figure 3 As shown, a third pipe 51 is sleeved on the outside of the second pipe 31;

[0079] A passage is formed between the third pipe 51 and the second pipe 31;

[0080] One end of the channel is connected to a telescopic bladder 52 located in the sealing section, and the other end extends to the outside of the borehole and is switched to an air source and a negative pressure source via a medium pipe 65.

[0081] Specifically, one end of the channel is connected to the medium pipe 65, and one end of the medium pipe 65 is equipped with a three-way valve and is connected to the air source and the negative pressure source respectively, thereby realizing the connection between the air source and the channel, and the connection between the negative pressure source and the channel;

[0082] Although negative pressure air extraction can expel gas from the sealing section and reduce the porosity formed inside the slurry, when the rock mass around the borehole is relatively loose or has a high water content, negative pressure will lead to an increase in the accumulation of liquid in the borehole or shrinkage and deformation of the borehole rock mass, which will damage the structure of the sealing section.

[0083] In this example, the expansion of the telescopic bladder 52 after inflation compresses the space of the sealing section, and the gas in the sealing section is squeezed out while maintaining the corresponding pressure. When the first burst valve 241 is opened, the slurry enters the sealing section. At this time, the telescopic bladder 52 can be squeezed out by the slurry, or the channel can be connected to the negative pressure source through the medium pipe 65 to actively contract the telescopic bladder 52 and let the gas inside it out.

[0084] As explained, the medium pipe 65 is equipped with a pressure gauge and an on / off valve. After the telescopic bladder 52 is inflated, it maintains a certain air pressure. When the first burst valve 241 is opened and the slurry enters the sealing section, increasing its pressure, the telescopic bladder 52 is compressed. The pressure gauge shows that the pressure inside the medium pipe 65 has increased. Then, the telescopic bladder 52 is vented.

[0085] In some examples of this utility model, such as Figure 3 As shown, the telescopic bladder 52 is a pleated structure folded along the length of the borehole, and the volume of the telescopic bladder 52 first increases along the length of the borehole and then increases radially.

[0086] Specifically, after the telescopic bladder 52 is filled with gas, it first extends along the length of the borehole, and then extends radially after reaching the entire sealing section. Therefore, it not only avoids the telescopic bladder 52 getting stuck in the sealing section, but also allows the telescopic bladder 52 to cover the entire sealing section as much as possible and expel the gas in the sealing section.

[0087] In some examples of this utility model, the first main capsule 22 and the second main capsule 23 are each provided with a first one-way valve for slurry to flow unidirectionally to the corresponding main capsule;

[0088] Both the first sub-capsule 32 and the second sub-capsule 33 are equipped with a second one-way valve for slurry to flow unidirectionally to the corresponding sub-capsule;

[0089] Specifically, the first and second check valves ensure unidirectional flow of the slurry;

[0090] During a single grouting operation, the first main bladder 22 and the second main bladder 23 are filled with grout first, and the grouting pressure gradually increases until the first burst valve 241 is opened. Due to the pressure reduction caused by the opening of the first burst valve 241, the first main bladder 22 and the second main bladder 23 may not be able to make close contact with the borehole wall, and there may even be a problem that the grout leaks out from between the main bladder and the borehole wall.

[0091] The first one-way valve can prevent slurry from flowing out of the corresponding main bladder after the first rupture valve 241 is opened. Correspondingly, during secondary grouting, the second one-way valve can prevent slurry from flowing out of the first auxiliary bladder 32 and the second auxiliary bladder 33 after the second rupture valve 34 is opened.

[0092] In some examples of this utility model, such as Figure 7 As shown, the exhaust component 35 consists of a branch pipe 351 and a slurry filter screen 353;

[0093] Branch pipe 351 is connected to the second pipe 31 and has multiple through holes;

[0094] The slurry-blocking filter screen 353 is wrapped around the outside of the through holes;

[0095] Furthermore, the second pipeline 31 is provided with a third check valve 352 for the medium to flow from the blocked section to the second pipeline 31;

[0096] Specifically, the grout-blocking filter 353 is used to filter water and air in the sealing section to prevent impurities in the sealing section from entering the second grouting pipe 62 and causing blockage; that is, when the sealing section is venting, the gas is normally discharged from the venting component 35 and the second pipe 31; when the sealing section is discharging grout, the grout passes through the grout-blocking filter 353 and can be discharged to prevent cement and other solidified substances in the grout from being discharged.

[0097] During secondary grouting, the third one-way valve 352 can unidirectionally block the second pipeline 31, thereby ensuring that the grout first enters the first secondary bladder 32 and the second secondary bladder 33 for sealing, and preventing the grout from entering the sealing section from the exhaust device 35, which would cause insufficient pressure in the corresponding secondary bladder.

[0098] When this dual-injection sealing device for coal mine gas extraction is used, the slurry enters the first main chamber 22 and the second main chamber 23 through the first pipe 21, which increases the volume of the corresponding main chambers and makes them fit against the borehole wall, forming a closed sealing section between them.

[0099] Switch the four-way valve 40 to connect the exhaust pipe 63 to the second pipe 31, and the negative pressure component is activated to actively discharge the gas in the sealing section; when the grouting pressure in the first pipe 21 reaches a certain value, the first burst valve 241 opens, and the grout gradually fills the sealing section and the cracks around the borehole, completing the first grouting.

[0100] After the borehole has been sealed for a period of time, the four-way valve 40 is switched to connect the second grouting pipe 62 to the second pipe 31. The grout enters the first auxiliary bladder 32 and the second auxiliary bladder 33 through the second pipe 31. The first auxiliary bladder 32 will increase in volume to fit the first main bladder 22, and the second auxiliary bladder 33 will increase in volume to fit the second main bladder 23, thus sealing the borehole a second time. When the grouting pressure in the second pipe 31 reaches a certain value, the second rupture valve 34 is opened, and the grout fills the sealed section and the cracks around the borehole, completing the secondary grouting.

[0101] The foregoing description, with reference to preferred embodiments, details an exemplary implementation of the coal mine gas extraction dual-injection sealing device proposed by this utility model. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of this utility model, and various combinations can be made to the various technical features and structures proposed by this utility model without exceeding the protection scope of this utility model, which is determined by the appended claims.

Claims

1. A dual-injection sealing device for coal mine gas drainage, comprising: The first main capsule (22) and the second main capsule (23) are arranged at intervals along the length of the borehole, and the first main capsule (22) is close to the borehole opening and forms a sealing section with the second main capsule (23); The first pipe (21) connects and passes through the first main bladder (22) and the second main bladder (23), providing slurry to cause the corresponding main bladder to expand and contact the borehole wall; a first burst valve (241) is provided on the first pipe (21) at the sealing section; Its characteristic is that it further includes: The first secondary capsule (32) and the second secondary capsule (33) are both transported through the second pipe (31) to expand and contact the borehole wall. The first secondary capsule (32) is attached to the first main capsule (22) and close to the borehole opening, and the second secondary capsule (33) is attached to the second main capsule (23) and close to the bottom of the borehole. The second pipe (31) connects and passes through the first sub-bladder (32) and the second sub-bladder (33), providing slurry to cause the corresponding sub-bladder to expand and contact the borehole wall; the second pipe (31) is equipped with a first burst valve (241) and an exhaust device (35) at the sealing section; The first pipe (21) is connected to the first grouting pipe (61); one end of the second pipe (31) is switched to be connected to the second grouting pipe (62), the exhaust pipe (63), and the grout discharge pipe (64).

2. The coal mine gas extraction dual-injection sealing device according to claim 1, characterized in that, One end of the second pipe (31) is connected to one end of the four-way valve (40); The other ends of the four-way valve (40) are connected to the second grouting pipe (62), the vent pipe (63), and the grout discharge pipe (64), respectively; The exhaust pipe (63) is connected to the negative pressure assembly.

3. The coal mine gas extraction dual-injection sealing device according to claim 2, characterized in that, The first rupture valve (241) is provided with a cylinder (242) with end-side sealing on the outside; The cylinder (242) is provided with multiple damping holes (246).

4. The coal mine gas extraction dual-injection sealing device according to claim 2, characterized in that, The first rupture valve (241) is provided with a cylinder (242) with end-side sealing on the outside; The cylinder (242) is provided with a through hole that communicates with its inner and outer sides; The sealing element (243) under the action of elastic force moves to be located in the through hole. When the pressure inside the cylinder (242) decreases, the sealing element (243) closes the through hole. When the pressure inside the cylinder (242) increases, the sealing element (243) opens the through hole.

5. The coal mine gas extraction dual-injection sealing device according to any one of claims 2 to 4, characterized in that, A third pipe (51) is fitted outside the second pipe (31); A passage is formed between the third pipe (51) and the second pipe (31); One end of the channel is connected to a telescopic bladder (52) located in the sealing section, and the other end extends to the outside of the borehole and is connected to the inflation source and negative pressure source via a medium pipe (65).

6. The coal mine gas extraction dual-injection sealing device according to claim 5, characterized in that, The telescopic bladder (52) is a folded structure folded along the length of the borehole, and the volume of the telescopic bladder (52) first increases along the length of the borehole and then increases radially.

7. The coal mine gas extraction dual-injection sealing device according to any one of claims 2 to 4, characterized in that, Both the first main capsule (22) and the second main capsule (23) are equipped with a first one-way valve for slurry to flow unidirectionally to the corresponding main capsule; Both the first sub-capsule (32) and the second sub-capsule (33) are equipped with a second one-way valve for slurry to flow unidirectionally to the corresponding sub-capsule.

8. The coal mine gas extraction dual-injection sealing device according to any one of claims 2 to 4, characterized in that, The exhaust component (35) consists of a branch pipe (351) and a slurry filter (353); The branch pipe (351) is connected to the second pipe (31) and has multiple through holes; the slurry-blocking filter screen (353) is wrapped around the outside of the through holes.

9. The coal mine gas extraction dual-injection sealing device according to claim 8, characterized in that, The second pipeline (31) is equipped with a third check valve (352) for the medium to flow from the blocked section to the second pipeline (31).

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