Drilling blowout preventer for mine coal seam gas extraction

Abstract

The utility model discloses a drilling blowout preventer for mine coal seam gas extraction, which comprises a blowout preventer main box and a buffer component, the blowout preventer main box is mounted at a drilling hole, and the upper end and the lower end of the blowout preventer main box are correspondingly provided with a first exhaust pipe and a first slag discharge pipe which are connected with an inner cavity; the buffering assembly is located in the blowout prevention main box and provided with a buffering plate and a supporting shaft of a hollow structure. One end of the supporting shaft is fixedly connected with the blowout prevention main box, and the other end faces a drill hole; the buffer plate is of a conical shell structure, and one end of a taper angle is close to the drill hole buffer plate, is slidably mounted on the supporting shaft and is subjected to elastic force towards the drill hole; one end of the drill rod piece is connected with the driving assembly, and the other end penetrates through the supporting shaft and extends into the coal seam for drilling. According to the utility model, the centralized impact of high-pressure gas, water and slag on the blowout prevention main box can be reduced, the risk of gas leakage is reduced, the non-uniform impact of the gas, water and slag on the buffer plate during extraction can be reduced, and the deformation of the fixedly arranged buffer plate due to long-time impact is avoided.

Description

Technical Field

[0001] This utility model relates to the field of coal mining technology, specifically to a borehole blowout prevention device for coal seam gas extraction in mines. Background Technology

[0002] During the gas extraction process, due to the non-uniformity of coal seam gas occurrence, the anisotropy of coal seam mechanical properties, and the drastic changes in coal body stress near the borehole, a large amount of coal powder and gas may be continuously ejected from the borehole in a short period of time, which is called borehole blowout. In a short period of time, a large amount of gas will be generated and exceed the standard. In severe cases, it can induce coal and gas outburst accidents, posing a huge safety hazard.

[0003] Therefore, blowout preventers need to be installed during the coal seam gas extraction process in mines. Currently, the commonly used blowout preventers are blowout preventer sleeves / valve / cylinders with multi-pass structures at the borehole port. The drilling rig controls the drill rod to pass through the blowout preventer sleeve to drill holes, and the blowout preventer sleeve is connected to the water slag mechanism and the gas extraction mechanism through multiple passages. For example, Chinese invention patent with publication number CN116291689A: A gas extraction borehole blowout adaptive multi-level buffer blowout preventer device.

[0004] In actual extraction, on the one hand, the rapidly ejected gas and water slag will directly impact the blowout preventer sleeve / valve / cylinder. The large and uneven impact will affect the sealing performance of the blowout preventer sleeve / valve / cylinder, especially between the drill rod and the blowout preventer sleeve / valve / cylinder, posing a risk of gas leakage. Furthermore, splashing water slag will impact the drill rod and the inside of the blowout preventer sleeve / valve / cylinder, preventing the gas, water, and slag from smoothly entering the separation mechanism. On the other hand, due to the influence of the extraction environment and usage, the drill rod is a hollow (through-hole) structure, and the end needs to be connected to other pipelines to ensure the supply of cooling water and air pressure to the drill rod and drill bit rod. For example, the patent with publication number CN117108343A: Blowout Preventer Device and Operating Method for Upward Drilling of Gas Extraction Holes in Downhole Drilling Sites. Moreover, as the coal seam drilling deepens, the drill rod adopts a multi-section structure, that is, multiple hollow intermediate rods need to be added to connect with each other to increase the drilling length. During disassembly and assembly, gas can easily overflow from the connection position of the intermediate rods, which also poses a risk of gas leakage. Summary of the Invention

[0005] The purpose of this utility model is to provide a borehole blowout prevention device for coal seam gas drainage in mines. It can not only reduce the concentrated impact of high-pressure gas, water and slag on the main blowout prevention box and reduce the risk of gas leakage, but also reduce the uneven impact of gas, water and slag on the buffer plate during drainage, and prevent the fixed buffer plate from deforming due to long-term impact.

[0006] To achieve the above objectives, this mine employs a borehole blowout prevention device for coal seam gas drainage, including:

[0007] The blowout preventer main box is installed at the drilled hole and has an inner cavity. The upper and lower ends are respectively provided with a first exhaust pipe and a first slag discharge pipe connected to the inner cavity.

[0008] The buffer assembly, located inside the main blowout preventer housing, consists of a buffer plate and a hollow support shaft.

[0009] One end of the support shaft is fixedly connected to the main blowout preventer housing, and the other end faces the drill hole;

[0010] The buffer plate has a conical shell structure, with one end of the cone angle close to the drill hole and the outer diameter of the cone bottom not less than the diameter of the drill hole. The buffer plate is slidably mounted on the support shaft and is subjected to elastic force towards the drill hole.

[0011] Among them, the buffer plate is closer to the drill hole than the first exhaust pipe and the first slag discharge pipe;

[0012] One end of the drill rod is connected to the drive assembly, and the other end extends through the support shaft into the coal seam to perform drilling operations.

[0013] In some examples of this utility model, the buffer plate is connected to the support shaft via a support member;

[0014] The support member is slidably mounted on the support shaft by means of a key, and the end near the drill hole is limited by a retaining ring, while the end away from the drill hole is provided with a first elastic member.

[0015] The first elastic element contacts the support and the adjusting cylinder respectively; the adjusting cylinder is connected to the support shaft.

[0016] In some examples of this utility model, the adjusting cylinder is threadedly mounted on the support shaft, with one end extending to the outside of the blowout preventer main housing.

[0017] In some examples of this utility model, the inner side of the buffer plate is rotatably mounted on the support member;

[0018] The outer periphery of the buffer plate is provided with multiple arc-shaped strips;

[0019] Multiple arc-shaped strips are arranged in the same direction, with one end gradually contracting towards the cone angle and the other end gradually extending in a circumferential arc shape;

[0020] When the buffer plate is impacted and under the action of the arc strip, the buffer plate rotates on its own and is positioned on the support.

[0021] In some examples of this utility model, a first sliding sealing ring is provided between the adjusting cylinder and the main blowout preventer;

[0022] A second sliding seal ring is provided between the support shaft and the drill rod.

[0023] In some examples of this utility model, the drill rod includes a drill bit rod, a plurality of intermediate rods, and a drive rod that is driven to rotate, which are connected in sequence.

[0024] Both the drill bit rod and the intermediate rod have axially movable sealing elements in the through holes at one end. The sealing elements are closed by elastic force.

[0025] A top piece extending axially outward is fixed in the through hole at the other end of the intermediate rod and at one end of the drive rod.

[0026] When the drill rod is connected to the intermediate rod, adjacent intermediate rods are connected to each other, and the intermediate rod is connected to the drive rod, the top member acts on the closing member to move it and open the through hole.

[0027] In some examples of this utility model, one end of the drill rod and the intermediate rod are provided with a cavity coaxial with the through hole;

[0028] The cavity is provided with a second elastic element and a ring fixed near the opening; the second elastic element is in contact with the bottom of the cavity and the sealing element respectively;

[0029] The closure element is located inside the cavity and is a coaxial stepped rod structure. Under the action of the second elastic element, the middle part of the closure element contacts one end face of the ring element to close it.

[0030] One end of the top part can pass through the ring part and act on the closing part.

[0031] In some examples of this utility model, the drive rod is provided with a collection box connected to the through hole for collecting gas, water and slag;

[0032] The collection box is rotatably and sealed on the drive rod and is equipped with a second slag discharge pipe and a second exhaust pipe connected to the inside;

[0033] Valves are installed on both the second slag discharge pipe and the second exhaust pipe.

[0034] In some examples of this utility model, the first slag discharge pipe and the second slag discharge pipe are respectively connected to the filter assembly;

[0035] The first and second exhaust pipes are respectively connected to the negative pressure assembly.

[0036] Compared with existing technologies, the borehole blowout preventer used for coal seam gas drainage in this mine has a buffer component inside the main blowout preventer box. The conical buffer plate allows gas, water, and slag to disperse from the center outwards along the circumference of the buffer plate, reducing the concentrated impact of high-pressure gas, water, and slag and lowering the risk of gas leakage. When the impact of gas, water, and slag is large, the buffer plate will slide on the support shaft, playing a buffering role and reducing damage to the buffer plate caused by long-term large impacts. In addition, multiple arc-shaped strips are provided on the outer periphery of the buffer plate. The impact on the arc-shaped strips causes the buffer plate to rotate, which can reduce the uneven impact of gas, water, and slag on the buffer plate during drainage and reduce the deformation of the fixed buffer plate due to long-term impact.

[0037] Since both the drill rod and the intermediate rod have axially movable sealing parts in the through holes at one end, and the other end of the intermediate rod and the drive rod have axially outward extending top parts fixed in the through holes at one end, when not connected, the sealing parts are closed by elastic force to the through holes of the corresponding rods. When connected, the top rod acts on the sealing parts to move and open the through holes. Therefore, without affecting the drilling conditions provided by the pipeline, gas leakage is effectively avoided during the disassembly and assembly of the intermediate rod. Attached Figure Description

[0038] Figure 1 This is an overall schematic diagram of the present invention;

[0039] Figure 2 This is a front view of the assembly of the buffer component and the main blowout preventer in this utility model;

[0040] Figure 3 This is a front view of the buffer component in this utility model;

[0041] Figure 4 This is a schematic diagram of the structure of the buffer plate in this utility model;

[0042] Figure 5 This is a front view of the structure of the middle rod in this utility model;

[0043] Figure 6 This is a front view of the adjacent intermediate rods in the connected state in this utility model;

[0044] Figure 7 This is a schematic diagram of the assembly of the top component and the intermediate rod in this utility model;

[0045] Figure 8 This is a front view of the assembly between the drive rod and the collection box in this utility model;

[0046] In the diagram: 10. Blowout preventer main box; 11. First slag discharge pipe; 12. First exhaust pipe;

[0047] 20. Intermediate rod; 21. Top piece; 211. Support ring; 212. Top rod; 22. Ring piece; 23. Closing piece; 24. Second elastic piece; 25. Cavity.

[0048] 30. Collection box; 31. Second slag discharge pipe; 32. Second exhaust pipe;

[0049] 40. Drive assembly; 41. Drive rod; 42. Slot;

[0050] 51. Fixed plate, 52. Support shaft, 53. Buffer plate, 531. Arc strip, 54. Support component, 55. First elastic component, 56. Adjusting cylinder. Detailed Implementation

[0051] 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.

[0052] 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.

[0053] like Figure 1 , Figure 2 , Figure 3 As shown, the coal seam gas drainage system in this mine uses a borehole blowout prevention device, which includes:

[0054] The blowout preventer main box 10 has an inner cavity, and the upper and lower ends are respectively provided with a first exhaust pipe 12 and a first slag discharge pipe 11 connected to the inner cavity;

[0055] The buffer assembly, located inside the main blowout shield 10, includes a buffer plate 53 and a hollow support shaft 52.

[0056] One end of the support shaft 52 is fixedly connected to the main blowout preventer 10, and the other end faces the drill hole;

[0057] The buffer plate 53 is a conical shell structure, with one end of the cone angle close to the drill hole and the outer diameter of the cone bottom not less than the diameter of the drill hole. The buffer plate 53 is slidably mounted on the support shaft 52 and is subjected to elastic force towards the drill hole.

[0058] Among them, the buffer plate 53 is close to the drill hole relative to the first exhaust pipe 12 and the first slag discharge pipe 11;

[0059] The drill rod passes through the support shaft 52, with one end connected to the drive assembly 40 and the other end extending into the coal seam to perform drilling operations.

[0060] Specifically, during drilling, the borehole opening is sealed to allow gas and water residue to enter the blowout preventer main box 10;

[0061] The blowout preventer main box 10 can be a closed cylinder, box or valve body structure, with an inner cavity and a through hole for the drilling parts to pass through. The first exhaust pipe 12 and the first slag discharge pipe 11 can be connected to the blowout preventer main box 10 by clamps or threads. The first exhaust pipe 12 is used to collect gas during the extraction process, and the first slag discharge pipe 11 is used to collect water slag during the extraction process.

[0062] The support shaft 52 in the buffer assembly has a hollow structure to facilitate the passage of drilling parts. One end of the support shaft 52 can extend to the outside of the blowout preventer main housing 10 and be fixedly installed on the blowout preventer main housing 10 by the fixing plate 51. That is, the fixing plate 51 is fixedly installed on the blowout preventer main housing 10 by welding or bolts. One end of the support shaft 52 is then bolted to the fixing plate 51, and the other end is located inside the blowout preventer main housing 10 for support.

[0063] The buffer plate 53 is made of hard, corrosion-resistant material to reduce deformation or damage caused by the large impact of gas and slag; a retaining ring may be provided at one end of the support shaft 52 near the borehole opening, which is used to limit the buffer plate 53.

[0064] Relative to the first exhaust pipe 12 and the first slag discharge pipe 11, the buffer plate 53 is close to the borehole. Its purpose is to ensure that the gas and slag pass through the buffer plate 53 first and then be discharged from the first exhaust pipe 12 and the first slag discharge pipe 11 during the extraction process.

[0065] The drill bit at one end of the drill rod extends into the coal seam to perform drilling operations, and the other end can be connected to the drive assembly 40 for power input. The drill rod is a hollow tube structure, and the other end is connected to the air pressure or water supply pipeline to facilitate the supply of cooling water and air pressure to the drill bit for drilling conditions. This is a conventional structure and will not be further elaborated here.

[0066] When the coal seam gas drainage system in this mine is used, the drill rod is inserted into the coal seam and a hole is drilled. The high-pressure gas and water slag generated during the drilling enter the inner cavity of the main blowout preventer box 10 in a short time.

[0067] The buffer plate 53 receives high-pressure gas and water slag. The conical structure allows the gas, water, and slag to disperse from the center outwards along the perimeter of the buffer plate 53, reducing the concentrated impact of high-pressure gas, water, and slag, especially on the sealing structure between the drilled part and the blowout preventer 10, thus reducing the risk of gas leakage. When the impact of gas, water, and slag is large, the buffer plate 53 will slide on the support shaft 52, i.e., away from the drill hole, to play a buffering role and reduce the damage to the buffer plate 53 caused by long-term large impacts.

[0068] After the impact force of the gas, water, and slag decreases through the buffer plate 53, the gas is discharged from the first exhaust pipe 12 at the top and the water and slag are discharged from the first slag discharge pipe 11 at the bottom. It is noted that the first exhaust pipe 12 can be connected to the negative pressure component of the pump, and a filter screen for filtering water and slag is provided at the connection between the first exhaust pipe 12 and the blowout prevention main box 10. The first slag discharge pipe 11 can be connected to the filter component for separating the slag from the water.

[0069] In some examples of this utility model, such as Figure 3 As shown, the support member 54 is slidably mounted on the support shaft 52, and the end near the drill hole is limited by a retaining ring, while the end away from the drill hole is provided with a first elastic member 55.

[0070] The first elastic element 55 contacts the support element 54 and the adjusting cylinder 56 respectively; the adjusting cylinder 56 is connected to the support shaft 52.

[0071] Specifically, the support member 54 can be connected to the support shaft 52 by a flat key or spline. The end of the support shaft 52 near the drill hole can be threaded. The retaining ring is threaded on the support shaft 52 to limit the movement of the support member 54 toward the drill hole.

[0072] The first elastic element 55 can be a cylindrical spring, located between the support element 54 and the adjusting cylinder 56;

[0073] In the initial state, under the action of the first elastic member 55, the support member 54 is close to the drill hole. After the buffer plate 53 is impacted, it can compress the first elastic member 55. After the impact decreases, the buffer plate 53 can return to the initial position.

[0074] Furthermore, such as Figure 2 , Figure 3 As shown, the adjusting cylinder 56 is threaded onto the support shaft 52, with one end extending to the outside of the blowout preventer main housing 10;

[0075] Specifically, the adjusting cylinder 56 is threaded onto the support shaft 52 and can move axially relative to the support shaft 52 to adjust the elastic force of the first elastic element 55. That is, when the adjusting cylinder 56 is close to the drill hole, the deformation of the first elastic element 55 increases and the buffer plate 53 is subjected to an increased elastic force. When the adjusting cylinder 56 is away from the drill hole, the deformation of the first elastic element 55 decreases and the buffer plate 53 is subjected to a decreased elastic force.

[0076] One end of the adjusting cylinder 56 extends to the outside of the main blowout preventer 10 to facilitate rotation and adjustment of the adjusting cylinder 56;

[0077] This example controls the deformation of the first elastic element 55 by moving the adjusting cylinder 56, thereby adjusting the elastic force on the buffer plate 53 towards the borehole to accommodate the different degrees of impact on the buffer plate 53 by gas and slag during the extraction process.

[0078] In some examples of this utility model, such as Figure 4 As shown, the buffer plate 53 is rotatably mounted on the support member 54 on its inner side;

[0079] The outer periphery of the buffer plate 53 is provided with multiple arc-shaped strips 531;

[0080] Multiple arc-shaped strips 531 are arranged in the same direction, with one end gradually contracting towards the cone angle and the other end gradually extending in a circumferential arc shape;

[0081] When the buffer plate 53 is impacted and under the action of the arc strip 531, the buffer plate 53 rotates on its own and is positioned on the support member 54.

[0082] Specifically, the buffer plate 53 can be rotatably mounted on the support member 54 via a bearing;

[0083] Although the conical shell structure of the buffer plate 53 can disperse the gas, water and slag from the middle along the perimeter of the buffer plate 53 to the outside, reducing the concentrated impact of high-pressure gas, water and slag, the fixed buffer plate 53 is prone to deformation under uneven impact for a long time.

[0084] When the buffer plate 53 is impacted by gas, water and slag, the impact acts on the arc-shaped strip 531, causing it to bear a circumferential force, thereby driving the buffer plate 53 to rotate on the support member 54. In this example, without affecting the axial movement of the support member 54 on the support shaft 52, the buffer plate 53 can rotate, which can reduce the uneven impact of gas, water and slag on the buffer plate 53 during extraction and reduce the deformation of the fixed buffer plate 53 due to long-term impact.

[0085] In some examples of this utility model, such as Figure 3 As shown, a first sliding sealing ring is provided between the adjusting cylinder 56 and the blowout preventer main box 10;

[0086] A second sliding seal ring is provided between the support shaft 52 and the drill rod;

[0087] Specifically, the first sliding seal ring is used to prevent gas, water, and slag from leaking between the regulating cylinder 56 and the blowout preventer main box 10, and the second sliding seal ring is used to prevent gas, water, and slag from leaking between the drill rod and the support shaft 52.

[0088] In some examples of this utility model, such as Figure 1 , Figure 5 , Figure 6 , Figure 7 As shown, the drill rod assembly includes a drill bit rod, a plurality of intermediate rods 20, and a drive rod 41 that is driven to rotate, which are connected in sequence.

[0089] Both the drill bit rod and the intermediate rod 20 have axially movable sealing elements 23 in the through holes at one end. The sealing elements 23 are closed by elastic force.

[0090] A top piece 21 extending outward is fixed in the through hole at the other end of the intermediate rod 20 and at one end of the drive rod 41;

[0091] When the drill rod is connected to the intermediate rod 20, adjacent intermediate rods 20 are connected to each other, and the intermediate rod 20 is connected to the drive rod 41, the top member 21 acts on the closing member 23 to move it and open the through hole.

[0092] Specifically, during the actual drilling process, the drill rod, multiple intermediate rods 20, and drive rod 41 are connected in sequence. The drilling depth is mainly adjusted by adding intermediate rods 20. The drill rod, intermediate rods 20 (hollow structure), and drive rod 41 all have through holes. After being connected in sequence, the corresponding pipelines are connected to the drill bit of the drill rod through the through holes to provide drilling conditions such as cooling water for the drill bit. The drive rod 41 is connected to the drive assembly 40 to realize the drilling power input of the drive rod 41. This is a conventional structure and will not be further elaborated here.

[0093] The top component 21 may include a fixedly arranged support ring 211 and a top rod 212 located in the middle of the support ring 211. The top rod 212 is connected to the support ring 211 by a connecting rod or a reinforcing rod. In the non-closed state, it can ensure the normal passage of gas, water and slag.

[0094] For ease of description, assume that there are three intermediate rods 20, namely A, B, and C, which are arranged from left to right along with the drill rod and drive rod 41. Then, the drill rod has a closing member 23 on the right side, the intermediate rod A has a top member 21 on the left side and a closing member 23 on the right side, and the drive rod 41 has a top member 21 on the left side.

[0095] When not connected, the closing member 23 closes the through hole of the corresponding rod body under the action of elastic force;

[0096] When the left side of the intermediate rod A is connected to the right side of the drill rod, the top member 21 on the intermediate rod A acts on the closing member 23 of the drill rod, causing it to move axially and open the through hole, that is, the through hole of the drill rod is connected to the through hole of the intermediate rod A. When the left side of the drive rod 41 is connected to the right side of the intermediate rod A, the top member 21 on the drive rod 41 acts on the closing member 23 of the intermediate rod A, causing it to move axially and open the through hole, that is, the through hole of the drive rod 41 is connected to the through hole of the intermediate rod A. The right side of the drive rod 41 can be connected to a corresponding pipeline to provide drilling conditions, or a valve can be provided on the right side of the drive rod 41 to realize opening and closing.

[0097] When intermediate rod B is installed, drive rod 41 is disengaged from intermediate rod A. The sealing member 23 of intermediate rod A is closed by the elastic force of the through hole, and the gas, water and slag extracted can strengthen the closure of the sealing member 23, effectively preventing the leakage of gas, water and slag. When intermediate rod B is connected to intermediate rod A, the sealing member 23 on the right side of intermediate rod B closes the through hole. Similarly, the left side of drive rod 41 is connected to the right side of intermediate rod B, completing the connection of the corresponding through hole.

[0098] When the intermediate rod C is installed, the drive rod 41 is disengaged from the intermediate rod B, and the sealing part 23 of the intermediate rod B is closed by the elastic force to prevent leakage of gas, water and slag. When the intermediate rod C is connected to the intermediate rod B, the sealing part 23 on the right side of the intermediate rod C closes the through hole. Similarly, the left side of the drive rod 41 is connected to the right side of the intermediate rod C to complete the connection of the corresponding through hole.

[0099] Furthermore, such as Figure 5 , Figure 6 As shown, one end of both the drill bit rod and the intermediate rod 20 is provided with a cavity 25 coaxial with the through hole;

[0100] The cavity 25 is provided with a second elastic element 24 and a ring 22 fixed and close to the opening; the second elastic element 24 is in contact with the bottom of the cavity 25 and the sealing element 23 respectively;

[0101] The closure member 23 is located inside the cavity 25 and is a coaxial stepped rod structure. Under the action of the second elastic member 24, the middle part of the closure member 23 contacts one end face of the ring member 22 to close.

[0102] One end of the top member 21 can pass through the ring member 22 and act on the closing member 23;

[0103] Specifically, the diameter of the cavity 25 is larger than the diameter of the through hole, so that the second elastic element 24 can contact the bottom of the cavity 25; the second elastic element 24 can be a corrosion-resistant cylindrical spring.

[0104] The cavity 25 may be provided with internal threads, and the ring 22 is threadedly installed on the cavity 25, through which air, water and slag are supplied; the sealing member 23 is a rod structure, the diameter of the middle part of this rod is larger than that on both sides, and it can contact one end face of the ring 22 to achieve closure;

[0105] In the initial state, the position of the adjustable ring 22 can be adjusted to adjust the elastic force of the second elastic element 24. Under the action of the second elastic element 24, the closing element 23 approaches the ring 22, and the middle shoulder of the rod contacts the end face of the ring 22 to close the through hole.

[0106] When the drill rod is connected to the intermediate rod 20, adjacent intermediate rods 20 are connected to each other, and the intermediate rod 20 is connected to the drive rod 41, one end of the top member 21 can pass through the ring member 22 and act on the closing member 23. That is, the top member 21 drives the closing member 23 away from the ring member 22, the hole in the middle of the ring member 22 is opened, and the through holes between the drill rod and the intermediate rod 20, adjacent intermediate rods 20, and the intermediate rod 20 and the drive rod 41 are interconnected.

[0107] In some examples of this utility model, such as Figure 1 , Figure 8 As shown, the drive rod 41 is provided with a collection box 30 connected to the through hole for collecting gas, water and slag;

[0108] The collection box 30 is rotatably and sealed on the drive rod 41 and is provided with a second slag discharge pipe 31 and a second exhaust pipe 32 connected to the inside;

[0109] Valves are installed on the second slag discharge pipe 31 and the second exhaust pipe 32;

[0110] Specifically, the drive rod 41 may be provided with a slot 42, which connects the through hole of the drive rod 41 and the inside of the collection box 30; the second exhaust pipe 32 is located at the upper end of the collection box 30, and the second slag discharge pipe 31 is located at the lower end of the collection box 30, and is provided with corresponding valves.

[0111] When the drill bit rod, multiple intermediate rods 20, and drive rod 41 are connected in sequence and the internal through holes are interconnected, the pipeline on the end side of the drive rod 41 can provide drilling conditions such as cooling water or air pressure to the drill bit rod. However, when the drilling does not require cooling water or air pressure, the pipeline can be closed. At this time, when the internal pressure of coal seam extraction is large, gas can easily leak from the connection of the drill rod components.

[0112] Therefore, a rotating sealed collection box 30 is provided on the drive rod 41. The purpose of the collection box 30 is to collect the gas inside the drill rod. When the pipeline on the end side of the drive rod 41 can provide drilling conditions such as cooling water or air pressure to the drill rod, that is, the pipeline is opened and the second slag discharge pipe 31 and the second exhaust pipe 32 are closed. At this time, normal drilling conditions can be provided. When the drilling does not require cooling water or air pressure, that is, the pipeline is closed and the second slag discharge pipe 31 and the second exhaust pipe 32 are opened. At this time, the gas, water and slag inside the drill rod will enter the collection box 30. The gas will be discharged from the second exhaust pipe 32 and the water slag will be discharged from the second slag discharge pipe 31.

[0113] In some examples of this utility model, the first slag discharge pipe 11 and the second slag discharge pipe 31 are respectively connected to the filter assembly;

[0114] The first exhaust pipe 12 and the second exhaust pipe 32 are respectively connected to the negative pressure assembly;

[0115] Specifically, the filter assembly is used to separate water and solids. Its structure can be a filter box, a filter screen located inside the filter box, and a first outlet and a second outlet on the filter box. The first outlet is located above the filter screen and is used to collect solids, while the second outlet is located below the filter screen and is used to collect water.

[0116] The negative pressure assembly is used to collect gas.

[0117] When this type of coal seam gas extraction drilling blowout prevention device is used, the drill bit rod, intermediate rod 20 and drive rod 41 in the drill rod are connected in sequence, so that their internal through holes are connected. The pipeline on the end side of the drive rod 41 can provide drilling conditions such as cooling water or air pressure to the drill bit rod.

[0118] The drill rod penetrates deep into the coal seam and drills holes. The drilling generates high-pressure gas and water slag, which enter the inner cavity of the blowout preventer main box 10 in a short time.

[0119] The buffer plate 53 receives high-pressure gas and water slag. The conical structure allows the gas, water, and slag to disperse from the center outwards along the circumference of the buffer plate 53, reducing the concentrated impact of the high-pressure gas, water, and slag. The impact acts on the arc-shaped strip 531, causing it to bear the circumferential force, thereby driving the buffer plate 53 to rotate on the support member 54. This reduces the uneven impact of gas, water, and slag on the buffer plate 53 during extraction. After passing through the buffer plate 53, the impact force of the gas, water, and slag decreases, and the gas is discharged from the first exhaust pipe 12 at the top, while the water slag is discharged from the first slag discharge pipe 11 at the bottom.

[0120] When the drilling depth is increased, the pipeline on the end side of the drive rod 41 is closed, and the drive rod 41 is disassembled from the intermediate rod 20 on the side. Under the action of the second elastic member 24, the sealing member 23 closes the through hole of the intermediate rod 20 on the side, and the gas, water and slag in the through hole cannot leak. When the new intermediate rod 20 is connected to the intermediate rod 20 on the side, the top member 21 at one end of the new intermediate rod 20 drives the sealing member 23 in the intermediate rod 20 on the side to move and open the through hole. The other end of the new intermediate rod 20 is closed and waiting for the drive rod 41 to dock. When the new intermediate rod 20 is connected to the drive rod 41, the through hole of the drill rod is still connected, and the pipeline on the end side of the drive rod 41 can still provide drilling conditions for the drill rod normally.

[0121] When the pipeline on the end of the drive rod 41 is closed, the gas, water and slag inside the drill rod will enter the collection box 30, the gas will be discharged from the second exhaust pipe 32 and the water slag will be discharged from the second slag discharge pipe 31.

[0122] The discharged water and sludge are separated by a filtration system, and the gas is extracted by a negative pressure system.

[0123] The foregoing description, with reference to preferred embodiments, details an exemplary implementation of the borehole blowout prevention device for coal seam gas extraction in mines 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. Mine coal seam gas drainage uses borehole blowout prevention devices, including: The blowout preventer main box (10) is installed at the drill hole and has an inner cavity. The upper and lower ends are respectively provided with a first exhaust pipe (12) and a first slag discharge pipe (11) connected to the inner cavity. Its characteristic is that it further includes: The buffer assembly, located inside the main blowout shield (10), has a buffer plate (53) and a hollow support shaft (52). One end of the support shaft (52) is fixedly connected to the main blowout preventer (10), and the other end faces the drill hole; The buffer plate (53) is a conical shell structure, with one end of the cone angle close to the borehole and the outer diameter of the cone bottom not less than the diameter of the borehole. The buffer plate (53) is slidably mounted on the support shaft (52) and subjected to elastic force towards the borehole. Among them, relative to the first exhaust pipe (12) and the first slag discharge pipe (11), the buffer plate (53) is close to the borehole; One end of the drill rod is connected to the drive assembly (40), and the other end extends through the support shaft (52) into the coal seam to perform drilling.

2. The borehole blowout prevention device for coal seam gas extraction in mines according to claim 1, characterized in that, The buffer plate (53) is connected to the support shaft (52) via a support member (54); The support member (54) is slidably mounted on the support shaft (52) by means of a key, and the end near the drill hole is limited by a retaining ring, while the end away from the drill hole is provided with a first elastic member (55). The first elastic element (55) contacts the support element (54) and the adjusting cylinder (56) respectively; the adjusting cylinder (56) is connected to the support shaft (52).

3. The borehole blowout prevention device for coal seam gas extraction in mines according to claim 2, characterized in that, The adjusting cylinder (56) is threaded onto the support shaft (52), with one end extending to the outside of the blowout preventer main box (10).

4. The borehole blowout prevention device for coal seam gas extraction in mines according to claim 2, characterized in that, The buffer plate (53) is rotatably mounted on the support (54) on its inner side; The outer periphery of the buffer plate (53) is provided with multiple arc-shaped strips (531); Multiple arc-shaped strips (531) are arranged in the same direction, with one end gradually contracting towards the cone angle and the other end gradually extending in a circumferential arc shape; When the buffer plate (53) is impacted and under the action of the arc strip (531), the buffer plate (53) rotates on its own and is positioned on the support (54).

5. The mine coal seam gas drainage borehole blowout prevention device according to any one of claims 2 to 4, characterized in that, A first sliding sealing ring is provided between the regulating cylinder (56) and the blowout preventer main box (10); A second sliding seal ring is provided between the support shaft (52) and the drill rod.

6. The mine coal seam gas drainage borehole blowout prevention device according to any one of claims 1 to 4, characterized in that, The drill rod assembly includes a drill bit rod, multiple intermediate rods (20) that are disassembled and connected in sequence, and a drive rod (41) that is driven to rotate. Both the drill rod and the intermediate rod (20) have axially movable sealing elements (23) in the through holes at one end. The sealing elements (23) are closed by elastic force. A top piece (21) extending outward is fixed in the through hole at the other end of the intermediate rod (20) and at one end of the drive rod (41). When the drill rod is connected to the intermediate rod (20), adjacent intermediate rods (20) are connected to each other, and the intermediate rod (20) is connected to the drive rod (41), the top member (21) acts on the closing member (23) to move it and open the through hole.

7. The mine coal seam gas drainage borehole blowout prevention device according to claim 6, characterized in that, One end of the drill rod and the intermediate rod (20) is provided with a cavity (25) coaxial with the through hole. The cavity (25) is provided with a second elastic element (24) and a ring (22) fixed and close to the opening; the second elastic element (24) is in contact with the bottom of the cavity (25) and the sealing element (23) respectively; The closure (23) is located inside the cavity (25) and is a coaxial stepped rod structure. Under the action of the second elastic element (24), the middle part of the closure (23) contacts one end face of the ring (22) to close. One end of the top piece (21) can pass through the ring piece (22) and act on the closing piece (23).

8. The mine coal seam gas drainage borehole blowout prevention device according to claim 7, characterized in that, The drive rod (41) is provided with a collection box (30) connected to the through hole for collecting gas, water and slag. The collection box (30) is sealed and rotatably mounted on the drive rod (41), and is provided with a second slag discharge pipe (31) and a second exhaust pipe (32) connected to the interior. Valves are installed on the second slag discharge pipe (31) and the second exhaust pipe (32).

9. The borehole blowout prevention device for coal seam gas extraction in mines according to claim 8, characterized in that, The first slag discharge pipe (11) and the second slag discharge pipe (31) are respectively connected to the filter assembly; the first exhaust pipe (12) and the second exhaust pipe (32) are respectively connected to the negative pressure assembly.

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