A three-proofing device for coal mine

Abstract

The application discloses a kind of three-proofing devices for coal mine, including outer tube, inner tube, slag discharge cylinder;Outer tube is connected with inner tube by positioning mechanism, and the outer end of slag discharge cylinder is provided with drill pipe sealing mechanism, and the peripheral portion close to the outer end of slag discharge cylinder is provided with gas extraction interface, coal slag discharge interface.The three-proofing device of the application can be installed on the drilling hole opening wall of gas extraction main pipeline construction, which can prevent fire, prevent back gas and prevent explosion;Among them, the drill pipe sealing assembly has the effect of blocking gas, so that it cannot enter the tunnel, which avoids the condition that gas leakage in drilling operation leads to the threat to the life safety of construction personnel, improves the safety of coal mining operation, and has perfect functionality, and has fixing and sealing effect simultaneously, effectively prevents gas leakage;And it is convenient to install, simple to disassemble, widely applicable, with large stroke range of expansion mechanism, can be applied to various aperture, can prevent spouting and outburst, further improves the use effect of the application.

Description

Technical Field

[0001] This invention relates to the field of coal seam mining equipment technology, and in particular to a three-proof device for coal mines. Background Technology

[0002] During coal seam mining, methane gas may leak from boreholes into the roadways, causing methane levels to exceed safe limits and threatening the lives of workers. Therefore, it is necessary to research a device to prevent methane leakage and address this problem. Summary of the Invention

[0003] The purpose of this invention is to address the above-mentioned problems by providing a coal mine gas prevention device that is simple in structure and easy to use, in order to prevent gas from leaking from boreholes into roadways.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] A coal mine three-proof device includes an outer cylinder that is detachably fixed to the borehole wall via a support mechanism, an inner cylinder that can slide and adjust relative to the outer cylinder, and a slag discharge cylinder that is fixedly connected to the inner cylinder; the outer cylinder and the inner cylinder are adjustablely connected via a positioning mechanism, the outer end of the slag discharge cylinder is provided with a drill rod sealing mechanism, and the periphery of the slag discharge cylinder near the outer end is provided with a gas extraction interface and a coal slag discharge interface.

[0006] As an improvement to the above technical solution, the inner cylinder is slidably disposed in the inner cavity of the outer cylinder; at the sliding fit with the inner and outer cylinders, the outer cylinder is provided with a through-hole adjustment groove in the axial direction so that part of the outer wall of the inner cylinder is exposed, and the expansion mechanism is disposed at the adjustment groove; the expansion mechanism includes a top rod hinged to the outer wall of the outer cylinder and a push rod hinged to the exposed outer wall of the inner cylinder, and the other end of the push rod passes through the adjustment groove and is hinged to the other end of the top rod.

[0007] As an improvement to the above technical solution, the expansion mechanism is in multiple groups, each group having multiple expansion mechanisms evenly distributed on the outer periphery of the outer cylinder. The multiple expansion mechanisms in one group and the multiple expansion mechanisms in adjacent groups are separated in the length direction and staggered in the circumferential direction. The multiple expansion mechanisms in the same group together include an annular support structure disposed on the outer periphery of the outer cylinder. The push rods of the multiple expansion mechanisms in the same group are hinged to the annular support structure by pins. Correspondingly, the multiple expansion mechanisms in the same group have multiple adjusting slots, and each of the multiple adjusting slots is provided with a hinge seat so that the multiple push rods of the same group are respectively hinged to their respective hinge seats by pins.

[0008] As an improvement to the above technical solution, multiple expansion mechanisms in two adjacent groups are staggered and evenly distributed in the circumferential direction. For example, if a group has three expansion mechanisms, the three expansion mechanisms in a group are evenly distributed in the circumferential direction, and there are a total of six expansion mechanisms in two adjacent groups, with the six expansion mechanisms staggered by 60° in the circumferential direction.

[0009] As an improvement to the above technical solution, the outer cylinder is provided with an outer cylinder flange at its outer end, the inner cylinder is provided with an inner cylinder flange at its outer end, and the slag discharge cylinder is provided with a slag discharge cylinder flange at its inner end; the inner cylinder flange is provided with a third mounting hole, and the slag discharge cylinder flange is provided with a corresponding fourth mounting hole; the inner cylinder and the slag discharge cylinder are fixedly connected by bolts passing through the third mounting hole and the fourth mounting hole; the positioning mechanism includes a positioning screw welded to the outer cylinder flange, a first mounting hole correspondingly provided on the inner cylinder flange, and a clearance hole correspondingly provided on the slag discharge cylinder flange; the other end of the positioning screw passes through the first mounting hole and the clearance hole; the positioning screw is threaded with a first positioning nut and a second positioning nut on both sides of the inner cylinder flange, so that the outer cylinder and the inner cylinder can be adjustedly connected by the positioning bolt, the first positioning nut, and the second positioning nut; the first positioning nut is recessed in the clearance hole.

[0010] As an improvement to the above technical solution, the drill pipe sealing mechanism has two types, including a first drill pipe sealing mechanism and a second drill pipe sealing mechanism; the first drill pipe sealing mechanism includes a pressure plate and a fixed cover with a cavity that is fixedly connected to the outer end of the slag discharge cylinder; the fixed cover is open to the outside, and a mounting screw is provided on the inner circumference of the cavity of the fixed cover; the pressure plate is provided with a through hole and is sleeved on the mounting screw through the through hole, pressing against the inner end face of the cavity; a sealing assembly is provided between the pressure plate and the inner end face of the cavity of the fixed cover; the part of the mounting screw that passes through the pressure plate is threadedly connected to a mounting nut.

[0011] As an improvement to the above technical solution, the pressure plate is annular in shape, and a spring is provided between the pressure plate and the mounting nut. After installation, the spring is in a compressed state, the purpose of which is to apply a small pressure to the sealing assembly through the pressure plate.

[0012] As an improvement to the above technical solution, the sealing assembly includes a left guard plate, a right guard plate, and several layers of rubber plates stacked sequentially. The rubber plates are positioned between the left and right guard plates, coaxially arranged with the left and right guard plates, and fixedly connected by pins. The two guard plates and the rubber plates can move around the pressure plate, with a maximum stroke of 20mm in each direction, to follow the swing of the drill rod (the drill rod swings continuously during drilling, affecting the seal). The left and right guard plates each have a clearance hole at their center, and the rubber plates each have a central hole at their center. Several extrusion slits are evenly spaced along the circumference of the rubber plate on the inner wall of the central hole, with the length of the extrusion slits aligned with the radial direction of the central hole. The slits are designed to prevent tearing of the rubber plates during drill rod swing; the staggered angles of the slits ensure a good seal.

[0013] As an improvement to the above technical solution, the extrusion gaps on adjacent rubber sheets in the plurality of layers of rubber sheets are staggered.

[0014] As an improvement to the above technical solution, the second drill pipe sealing mechanism includes a cover plate connected to the outer end of the slag discharge cylinder via a transition cylinder. A rear cylinder disposed on the outer side of the cover plate forms a cavity for placing polyurethane sealing rings. Multiple polyurethane sealing rings are stacked in the cavity of the rear cylinder, and adjacent polyurethane sealing rings are separated by spacers. A pressure plate is disposed on the outermost side of the cavity of the rear cylinder. The pressure plate is connected to the cover plate by bolts passing through the pressure plate, the polyurethane sealing rings, and the spacers.

[0015] As an improvement to the above technical solution, the cross-section of the polyurethane sealing ring is curved and funnel-shaped, with the small opening of the polyurethane sealing ring facing the inner side of the rear cylinder.

[0016] As an improvement to the above technical solution, the bottom end of the slag discharge interface is inclined toward the outer end of the slag discharge cylinder.

[0017] The three-proof device of the present invention is used as follows:

[0018] First, a larger borehole is drilled on the coal seam mining face. The inner ends of the outer cylinder and the inner cylinder are then inserted into the borehole. After the outer cylinder flange contacts the borehole end face, the worker tightens the first positioning nut to move the inner cylinder relative to the outer cylinder. Once in place, the second positioning nut is tightened to fix the outer cylinder and the inner cylinder relative to each other. At this time, the expansion and support mechanism expands and tightens the inner wall of the borehole, realizing the positioning operation of the outer cylinder and the inner wall of the borehole. Finally, the slag discharge cylinder is installed. When drilling in the coal seam, one end of the drill rod is passed through the drill rod sealing mechanism, the slag discharge cylinder, and the inner cylinder in sequence before drilling.

[0019] Compared with the prior art, the advantages and positive effects of this invention are:

[0020] The three-proof device of this invention can be installed on the borehole wall during the construction of the main gas drainage pipeline, effectively preventing fire, backflow, and explosion. The drill rod sealing assembly at the outer end of the slag discharge cylinder in the three-proof device provides a barrier, ensuring that gas ejected from the borehole enters the gas drainage equipment through the gas drainage interface, preventing it from entering the roadway. This avoids gas leakage into the roadway during drilling operations, thus preventing threats to the lives of construction personnel and improving the safety of coal mining operations. Its functionality is comprehensive, combining fixing and sealing effects to effectively prevent gas leakage. Furthermore, it is easy to install and disassemble, has a wide range of applications, and the expansion mechanism has a large stroke range, making it suitable for various borehole diameters. It can prevent blowouts and outbursts, further improving the effectiveness of this invention. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the present invention;

[0023] Figure 2 for Figure 1 A magnified view of the local structure;

[0024] Figure 3 This is a cross-sectional view of the present invention;

[0025] Figure 4 for Figure 3 A magnified view of the local structure;

[0026] Figure 5 This is a schematic diagram of the rubber sheet structure;

[0027] Figure 6 This is a schematic diagram of the second type of drill pipe sealing mechanism. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art to all other embodiments obtained without creative effort should be included within the protection scope of the present invention.

[0029] like Figures 1 to 5As shown in the figure, this embodiment discloses a three-proof device for coal mines, including an outer cylinder 1, an inner cylinder 2, and a slag discharge cylinder 3. The outer cylinder 1 is sleeved on the outside of one end of the inner cylinder 2, and the inner cylinder 2 can slide relative to the outer cylinder 1. One end of the outer cylinder 1 and one end of the inner cylinder 2 extend into the borehole. An expansion mechanism 4 is provided between the outer cylinder 1 and the inner cylinder 2, and the outer cylinder 1 is connected to the inner wall of the borehole through the expansion mechanism 4. An outer cylinder flange 101 is provided at the end of the outer cylinder 1 located at the borehole port, and an inner cylinder flange 201 is provided at the end of the inner cylinder 2 located outside the borehole. The outer cylinder flange 101 and the inner cylinder flange 201 are positioned by... The mechanisms are connected; one end of the slag discharge cylinder 3 is connected to the inner cylinder flange 201 and the interior of the slag discharge cylinder 3 is connected to the interior of the inner cylinder 2; a gas extraction port 302 for extracting gas leaking from the borehole is provided at the top middle part of the slag discharge cylinder 3, and a slag discharge port 303 for discharging slag generated during the drilling operation is provided at the bottom middle part of the slag discharge cylinder 3. The gas extraction port 302 is connected to the gas extraction equipment, and the slag discharge port 303 is connected to the slag collection container. A drill rod sealing mechanism 5 is provided at the end of the slag discharge cylinder 3 away from the inner cylinder 2.

[0030] The three-proof device is mainly used during drilling operations. It is typically a four-way system, with the drill rod passing through the borehole. The upper end connects to the gas extraction pipe, and the lower end connects to a water-slag separation device, which is fixed to the borehole wall. During normal operation, water and slag enter the coal-water separation device through the lower outlet, while gas is extracted through the upper outlet. If a blowout is encountered during drilling, a large amount of gas will be blocked within the borehole by the blowout preventer, and the gas will be extracted through the extraction pipe. This prevents a large amount of gas from escaping into the roadway in a short period, causing gas exceedances and affecting operational safety.

[0031] In use, this invention first involves drilling a large borehole on the coal seam face. Then, one end of the outer cylinder and one end of the inner cylinder are inserted into the borehole. After the outer cylinder flange contacts the coal seam borehole wall, the inner cylinder is pushed to move relative to the outer cylinder. At this time, the expansion mechanism expands and tightens the inner wall of the borehole, achieving the positioning operation between the outer cylinder and the inner wall of the borehole. Next, the connection structure between the inner and outer cylinders is defined by the positioning mechanism. Finally, the slag discharge cylinder is installed. During coal seam drilling, one end of the drill rod is passed through the drill rod sealing mechanism, the slag discharge cylinder, and the inner cylinder in sequence before drilling. Due to the obstruction of the drill rod sealing assembly, the gas ejected from the borehole will enter the gas extraction equipment through the gas extraction interface and will not enter the roadway. This avoids the situation where gas leaks into the roadway during drilling operations, threatening the lives of construction personnel and improving the safety of coal mining operations.

[0032] The expansion mechanism 4 includes a top rod 401 and a push rod 402. One end of the top rod 401 is connected to the outer wall of the outer cylinder 1 by a pin, and the other end of the top rod 401 is connected to one end of the push rod 402 by a pin. The outer cylinder 1 has a long groove 103 (adjusting long groove) on its side wall. The end of the push rod 402 away from the top rod 401 passes through the long groove 103 (adjusting long groove) and is connected to the outer wall of the inner cylinder 2 by a pin. When the inner cylinder 2 moves relative to the outer cylinder 1, the push rod 402 moves in the long groove 103.

[0033] The outer cylinder 1 is provided with an annular support structure 102, and the annular support structure 102 is sequentially fixedly sleeved on the outer side of the outer cylinder 1 along the axial direction of the outer cylinder 1; the expansion mechanism 4 is provided at equal intervals along the circumferential direction of the annular support structure 102; the end of the push rod 401 in the expansion mechanism 4 away from the push rod 402 is connected to the pin shaft of the annular support structure 102.

[0034] The push rod and the push rod form a linkage mechanism, which works on a similar principle to an expansion bolt. As the inner cylinder continues to move into the larger borehole relative to the outer cylinder, the push rod and the push rod rotate and tilt, generating an outward expansion action. When the ends of the push rod and the push rod are pressed and tightened against the inner wall of the borehole, a stable connection structure between the outer cylinder and the borehole is achieved. When the drill rod rotates and drills inside the inner cylinder, the outer cylinder and the inner cylinder do not move relative to the larger borehole.

[0035] The positioning mechanism includes a positioning screw 6, a first positioning nut 8, and a second positioning nut 7. A slag discharge cylinder flange 301 is provided at one end of the slag discharge cylinder 3 near the inner cylinder 2. The slag discharge cylinder flange 301 is correspondingly provided with the inner cylinder flange 201 and the two are connected by bolts. A second mounting hole is provided on the slag discharge cylinder flange 301. One end of the positioning screw 6 is welded to the outer cylinder flange 101. The other end of the positioning screw 6 passes through the first mounting hole provided on the inner cylinder flange 201 and the second mounting hole provided on the slag discharge cylinder flange 301 in sequence and is threadedly connected to the first positioning nut 8. The second positioning nut 7 is provided between the outer cylinder flange 101 and the inner cylinder flange 201 and is threadedly connected to the positioning screw 6.

[0036] The inner cylinder and the slag discharge cylinder are connected by bolts. When the expansion mechanism tightens the inner wall of a larger borehole, the first positioning nut is tightened, and then the second positioning nut is tightened, thus achieving the positioning operation between the inner cylinder and the outer cylinder. During disassembly, the first positioning nut is loosened, and the second positioning nut is tightened to move towards the inner cylinder flange, squeezing the inner cylinder flange and causing the inner cylinder to move outward from the borehole. This causes the expansion mechanism to contract, allowing the outer cylinder to detach from the inner wall of the borehole, thus making it easy to remove the outer cylinder and the inner cylinder from the borehole.

[0037] The drill pipe sealing mechanism 5 includes a fixed cover 501, which is fixedly connected to the end of the slag discharge cylinder 3 away from the inner cylinder 2. A pressure plate 502 is provided inside the fixed cover 501. The pressure plate 502 is annular. An installation screw 503 is provided on the fixed cover 501. One end of the installation screw 503 passes through the through holes provided on the fixed cover 501 and the pressure plate 502 in sequence and is threadedly connected to the installation nut 504. A spring 505 is sleeved on the outside of the installation screw 503 and the spring 505 is located between the pressure plate 502 and the installation nut 504. A sealing assembly 9 is provided between the pressure plate 502 and the fixed cover 501.

[0038] The sealing assembly 9 includes a left protective plate 901, a right protective plate 902, and a plurality of rubber plates 903 stacked sequentially. The plurality of rubber plates 903 are disposed between the left protective plate 901 and the right protective plate 902. The rubber plates 903, the left protective plate 901, and the right protective plate 902 are coaxially arranged and fixedly connected by pins 904. A plurality of extrusion gaps 9032 are equally spaced along the circumference of the rubber plate 903 on the inner side wall of the central hole 9031. The length direction of the extrusion gaps 9032 is consistent with the radial direction of the central hole 9031. The extrusion gaps 9032 on adjacent rubber plates 903 are staggered.

[0039] To ensure a tight seal, this application also provides a second drill pipe sealing mechanism, such as... Figure 6 As shown, the system includes a cover plate 1102 connected to the outer end of the slag discharge cylinder 3 via a transition cylinder 1101. A rear cylinder 1104 is disposed outside the cover plate 1102, forming a cavity within the rear cylinder 1104 for placing polyurethane sealing rings 1107. Multiple polyurethane sealing rings 1107 are stacked within the cavity of the rear cylinder 1104, with adjacent polyurethane sealing rings 1107 separated by spacers 1103. A pressure plate 1105 is disposed on the outermost side of the cavity of the rear cylinder 1104. The pressure plate 1105 is connected to the cover plate 1102 by bolts 1106 passing through the pressure plate 1105, the polyurethane sealing rings 1107, and the spacers 1103. The polyurethane sealing ring 1107 has a curved trumpet-shaped cross-section, with the smaller opening of the polyurethane sealing ring 1107 facing inward towards the rear cylinder.

[0040] The three-proof device is mainly used during drilling operations. It is typically a four-way system, with the drill rod passing through the borehole, the upper end connected to a gas extraction pipe, and the lower end connected to a water-slag separator fixed to the coal face. During normal operation, water and slag enter the coal-water separator through the lower outlet, while gas is extracted through the upper outlet. If a blowout is encountered during drilling, a large amount of gas will be blocked within the borehole by the blowout preventer, and the gas will be extracted through the extraction pipe. This prevents a large amount of gas from escaping into the roadway in a short period, causing gas exceedances and affecting operational safety.

[0041] The drill rod passes through the center of the pressure plate and then sequentially through the center holes of the right protective plate, rubber plate, and left protective plate before extending into the slag discharge cylinder. The sealing assembly, under the elastic force of the spring, is pressed between the fixed cover and the pressure plate. This allows the sealing assembly to move slightly within the space between the pressure plate and the fixed cover with the drill rod during drilling, ensuring that the sealing effect of the sealing assembly on the outer circumference of the drill rod is not affected by the drilling motion. Simultaneously, the inner diameter of the center hole on the rubber plate is slightly smaller than the outer diameter of the drill rod, thus ensuring that after the drill rod is inserted into the center hole... The inner wall of the central hole can tightly wrap around the outer circumference of the drill rod. The design of the compression gap on the inner wall of the central hole not only facilitates the insertion of the drill rod, but also keeps the outer wall of the drill rod in contact with the inner wall of the central hole when the drill rod shakes during drilling, effectively preventing gas leakage and further improving the sealing effect of the invention. When disassembling, first remove the slag discharge cylinder, tighten the second positioning nut to pull the inner cylinder outward, gradually causing the expansion mechanism to retract, and finally remove the inner and outer cylinders. The disassembly process is simple and quick, further improving the use effect of the invention.

Claims

1. A three-proofing device for coal mines, characterized by: The outer cylinder is detachably fixed to the borehole wall through a spreader mechanism, the inner cylinder is slidably adjusted relative to the outer cylinder, and the slag discharge cylinder is fixedly connected to the inner cylinder; the outer cylinder and the inner cylinder are adjustably connected through a positioning mechanism, the outer end of the slag discharge cylinder is provided with a drill rod sealing mechanism, and the peripheral part close to the outer end of the slag discharge cylinder is provided with a gas extraction interface and a coal slag discharge interface; The inner cylinder is slidably arranged in the inner cavity of the outer cylinder; at the sliding fit position of the inner cylinder and the outer cylinder, the outer cylinder is provided with a through adjusting long slot in the axial direction, so that part of the outer wall of the inner cylinder is exposed, and the spreader mechanism is arranged at the adjusting long slot; the spreader mechanism comprises a top rod hinged to the outer wall of the outer cylinder and a push rod hinged to the exposed outer wall of the inner cylinder, and the other end of the push rod is hinged to the other end of the top rod through the adjusting long slot. The spreader mechanism is composed of multiple groups of spreader mechanisms, each group of spreader mechanisms is distributed on the outer periphery of the outer cylinder, the multiple spreader mechanisms of one group and the multiple spreader mechanisms of an adjacent group are spaced apart in the length direction and are arranged in a staggered manner in the circumferential direction; the multiple spreader mechanisms of the groups collectively comprise an annular support structure arranged on the outer periphery of the outer cylinder, and the top rods of the multiple spreader mechanisms of the groups are hinged to the annular support structure through a pin shaft; correspondingly, the multiple spreader mechanisms of the groups correspond to multiple adjusting long slots, and the multiple adjusting long slots are respectively provided with a hinge seat, so that the multiple push rods of the groups are respectively hinged to the respective hinge seats through a pin shaft.

2. The coal mine three-proofing device according to claim 1, characterized in that: The outer end of the outer cylinder is provided with an outer cylinder flange, the outer end of the inner cylinder is provided with an inner cylinder flange, and the inner end of the slag discharge cylinder is provided with a slag discharge cylinder flange; a third mounting hole is arranged on the inner cylinder flange, a fourth mounting hole is correspondingly arranged on the slag discharge cylinder flange, and the inner cylinder and the slag discharge cylinder are fixedly connected through bolts penetrating the third mounting hole and the fourth mounting hole; the positioning mechanism comprises a positioning screw rod welded to the outer cylinder flange, a first mounting hole correspondingly arranged on the inner cylinder flange, and a relief hole correspondingly arranged on the slag discharge cylinder flange; the other end of the positioning screw rod penetrates the first mounting hole and the relief hole; the positioning screw rod is threadedly connected with a first positioning nut and a second positioning nut on both sides of the inner cylinder flange, so that the outer cylinder and the inner cylinder are adjustably connected through the positioning screw rod, the first positioning nut and the second positioning nut; the first positioning nut is arranged in the relief hole.

3. The coal mine three-proofing device according to claim 2, characterized in that: The drill rod sealing mechanism has two types, including a first drill rod sealing mechanism and a second drill rod sealing mechanism; the first drill rod sealing mechanism comprises a pressing plate and a fixed cover fixedly connected to the outer end of the slag discharge cylinder and having a cavity; the fixed cover is outwardly open, the cavity of the fixed cover is provided with a mounting screw on the inner periphery, the pressing plate is correspondingly provided with a through hole and is sleeved on the mounting screw through the through hole to press the inner end face of the cavity, and a sealing assembly is arranged between the pressing plate and the inner end face of the cavity of the fixed cover; the part of the mounting screw penetrating the pressing plate is threadedly connected with a mounting nut.

4. The coal mine three-proofing device according to claim 3, characterized in that: The pressing plate is in the shape of an annular plate, and a spring is arranged between the pressing plate and the mounting nut.

5. The coal mine three-proofing device according to claim 3, characterized in that: The sealing assembly comprises a left guard plate, a right guard plate and a plurality of rubber plates arranged in sequence, the plurality of rubber plates are arranged between the left guard plate and the right guard plate, the plurality of rubber plates and the left guard plate and the right guard plate are coaxially arranged and are fixedly connected through a pin; the left guard plate and the right guard plate are both provided with an avoiding hole at a center position, the plurality of rubber plates are provided with a center hole at a center position, a plurality of extrusion gaps are arranged on an inner side wall of the center hole of the rubber plate along a circumferential direction of the rubber plate at equal intervals, and a length direction of the extrusion gap is consistent with a radial direction of the center hole.

6. The coal mine three-proofing device according to claim 5, characterized in that: Among the plurality of rubber plates, the extrusion gaps on adjacent rubber plates are arranged in a staggered manner.

7. The coal mine three-proofing device according to claim 3, characterized in that: The second drill rod sealing mechanism comprises a cover plate connected to an outer end of the residue discharging cylinder through a transition cylinder, a rear cylinder arranged outside the cover plate, an inner cavity of the rear cylinder forming a cavity for placing polyurethane sealing rings, a plurality of polyurethane sealing rings stacked in the cavity, adjacent polyurethane sealing rings being separated by a spacer sleeve, a pressing plate arranged at an outermost side of the cavity of the rear cylinder, and the pressing plate being connected to the cover plate through bolts penetrating the pressing plate, the polyurethane sealing rings and the spacer sleeve.

8. The coal mine three-proofing device according to claim 7, characterized in that: A cross section of the polyurethane sealing ring is in a curved trumpet shape, a small opening of the polyurethane sealing ring is directed to an inner side direction of the rear cylinder, and a bottom end of the coal residue discharging interface is obliquely arranged towards the outer end of the residue discharging cylinder.

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