An equipment for preventing coal loss during coring of soft coal seam and a working method thereof

Abstract

The application discloses a kind of equipment and working method of preventing coal chip loss in the process of soft coal seam coring, equipment includes hollow drill bit, coal chip collection tank, coring tube, anti-loss assembly;Its working method includes the following steps: S1, using drilling machine, drill rod and drilling bit to construct a sample drilling;S2, hollow drill bit, coring tube, coal chip collection tank, drill rod are connected and pushed to the predetermined sampling position;S3, after reaching the predetermined sampling position, start drilling machine to drive hollow drill bit to rotate and cut coal sample, coal sample enters into coring tube and extrudes anti-loss assembly, anti-loss assembly opens, coal sample enters into coal chip collection tank through coring tube;S4, after coring is completed, anti-loss assembly is closed, coal sample is enclosed in coring tube and coal chip collection tank;S5, after drill rod, hollow drill bit, coring tube, coal chip collection tank are all taken out, drill rod is separated from coal chip collection tank, coring tube is disassembled, and coal chip can be obtained in coal chip collection tank.

Description

Technical Field

[0001] This invention relates to the field of coal seam sampling, and in particular to an equipment and its working method for preventing coal dust loss during coring of soft coal seams. Background Technology

[0002] Coalbed methane is a major cause of gas disasters, but it is also a clean energy source that can optimize the energy industry structure. Therefore, effective control of coalbed methane is crucial for achieving dual carbon targets and alleviating environmental pressures. A prerequisite for effective coalbed methane control is understanding its content, as coalbed methane content measurement is necessary for coal seam outburst risk assessment, regional effectiveness verification, extraction effectiveness evaluation, and regional prediction.

[0003] Methods for determining coal seam gas content include direct underground measurement (GB / T23250-2009) and indirect methods. Indirect methods primarily involve calculations based on coal seam gas pressure, coal adsorption constant, moisture content, ash content, porosity, and apparent density. However, the Detailed Rules for the Prevention and Control of Coal and Gas Outbursts (2022) have specific requirements for the use of direct methods to determine coal seam gas content. For example, regional predicted coal seam gas pressure and gas content parameters should be based on actual underground measurements, and fixed-point sampling should be used when determining gas content using direct methods. The effectiveness of protective layers in mining is primarily verified using residual gas pressure, residual gas content, and other experimentally proven indicators and methods; residual gas pressure and residual gas content used in these verifications must be measured values. For regional outburst prevention measures using pre-drainage of coal seam gas, the effectiveness of these measures must be verified, with residual gas content being the preferred verification indicator, and the residual gas content should be a measured value.

[0004] The direct method for measuring coal seam gas underground (GB / T23250-2009) stipulates that coring tube sampling should be the first choice when measuring coal seam gas content. The coring tube sampling process is as follows: First, drill a borehole using a drilling rig; second, remove the drill rod, install the coring tube on the drilling rig, and connect the drill rod behind the coring tube; finally, send the coring tube to the location to be sampled through the drill rod for coring. This sampling method has been widely used in major mining areas across the country. Core sampling is effective for upward boreholes with slightly larger inclination angles, and coal dust is less likely to be lost during the withdrawal of the drill rod after sampling. However, for upward boreholes with near-horizontal inclination angles and downward boreholes, especially in soft coal seams, the coal dust is granular, and the friction between the dust and the inner wall of the core tube is low. During the withdrawal of the drill rod after sampling, the unsealed cutting end of the core tube makes it easy for coal dust to be lost, leading to failed coal seam gas content tests or poor test accuracy. Therefore, it is necessary to provide equipment and its operating method to prevent coal dust loss during core sampling in soft coal seams, so as to achieve coal dust-free coring in near-horizontal and downward boreholes, thereby improving the efficiency and accuracy of coal seam gas content determination. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned problems by providing a simple and convenient equipment and operating method for preventing coal dust loss during coring of soft coal seams.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] An apparatus for preventing coal dust loss during coring in soft coal seams includes a hollow drill bit, a coal dust collection tank, a coring tube, and an anti-loss component. One axial end of the coring tube is detachably connected to the hollow drill bit, and the other axial end of the coring tube is detachably connected to one axial end of the coal dust collection tank. The other axial end of the coal dust collection tank is detachably connected to one end of the drill rod. The anti-loss component is fixedly connected inside the coring tube. The anti-loss component includes several sets of baffle mechanisms and several sets of lifting and sealing mechanisms. The baffle mechanisms and lifting and sealing mechanisms are correspondingly arranged, and the lifting and sealing mechanisms are located below the baffle mechanisms and connected to the baffle mechanisms through a spring-loaded mechanism.

[0008] Furthermore, the baffle mechanism comprises four sets, arranged along the circumference of the core tube; each baffle mechanism includes a limiting block and a closing blade; one side wall of the limiting block is arc-shaped and its arc end face is fixedly connected to the inner wall of the core tube; in the four sets of baffle mechanisms, the arc end faces of the four limiting blocks are connected end to end and enclose a central area; the end of the limiting block away from the inner wall of the core tube is connected to the closing blade pin, and the closing blade is triangular in shape; in the four sets of baffle mechanisms, the four closing blades block and close the central area when in a horizontal state.

[0009] Furthermore, the end face of the limiting block away from the inner wall of the core tube is set as a first vertical plane, and the bottom of the end of the limiting block away from the inner wall of the core tube is set as a convex arc surface. The top of the convex arc surface is connected to the first vertical plane, and a vertical limiting groove is provided at the bottom of the convex arc surface. The end face of the closing blade near the limiting block is set as a second vertical plane, and a vertical limiting protrusion is provided at the bottom of the second vertical plane. The upper end face of the vertical limiting protrusion is set as a concave arc surface that matches the convex arc surface, and the top of the concave arc surface is connected to the second vertical plane. When the closing blade is in a horizontal state, the first vertical plane and the second vertical plane abut against each other. When the closing blade is opened, the closing blade rotates downward, and the convex arc surface and the concave arc surface generate sliding friction until the vertical limiting protrusion is embedded in the vertical limiting groove. At this time, the closing blade is in a vertical state.

[0010] Furthermore, the end face of the limiting block away from the inner wall of the core tube is provided with an installation groove, and the end face of the closing blade near the limiting block is provided with an installation protrusion. The installation protrusion is inserted into the installation groove and the installation protrusion and the installation groove are connected by an installation shaft pin.

[0011] Furthermore, the rebound mechanism includes a spring and a transmission rod. One end of the transmission rod is connected to the bottom pin of the closed blade, the other end of the transmission rod is connected to the lifting and sealing mechanism, the middle part of the transmission rod is connected to one end of the spring, and the other end of the spring is connected to the bottom of the limiting block.

[0012] Furthermore, the lifting and sealing mechanism includes a protective cover, a fixed rack, and a movable gear. The protective cover is a rectangular cylindrical shell, located below the limiting block, and fixedly connected to the inner wall of the core tube. A fixed rack is fixedly connected to the inner wall of the protective cover and is arranged longitudinally. The outer teeth of the movable gear mesh with the teeth of the fixed rack. A movable shaft is rotatably connected to the center of the movable gear and is coaxial with the movable gear. One end of the movable shaft is connected to the movable gear, and the other end of the movable shaft passes through a longitudinal opening on the side wall of the protective cover and is connected to a pin at one end of the transmission rod. When the movable gear rolls longitudinally along the fixed rack, the movable shaft slides longitudinally within the longitudinal opening.

[0013] Furthermore, the protective cover is equipped with four rotating shafts, the axis of which is consistent with the width direction of the longitudinal opening. The four rotating shafts are distributed at the four corners of the protective cover, and both ends of the rotating shafts are rotatably connected to the inner wall of the protective cover. Flexible baffles are sleeved on the outside of the four rotating shafts and can rotate around the four rotating shafts. One side wall of the flexible baffle is parallel to the side wall of the protective cover to which the longitudinal opening belongs, and the flexible baffle is located inside the longitudinal opening. The side of the flexible baffle near the longitudinal opening is provided with a clearance hole for connecting to the movable shaft. When the movable shaft is connected to the transmission rod, one end of the movable shaft passes through the clearance hole on the flexible baffle and the longitudinal opening of the side wall of the protective cover in sequence, and then connects to one end of the transmission rod with a pin.

[0014] Furthermore, the inner wall of the protective cover with the longitudinal opening is provided with a sealing protrusion. There are two sealing protrusions, and the two sealing protrusions are respectively located on both sides of the width direction of the longitudinal opening. A sealing clearance groove is provided on the side of the sealing protrusion near the flexible baffle, and the sealing clearance groove avoids the movement of the flexible baffle.

[0015] Furthermore, the two axial ends of the core tube are threadedly connected to the hollow drill bit and the coal dust collection tank, respectively. The inner wall of the coal dust collection tank away from the core tube is provided with a sealing cap, and the end of the coal dust collection tank away from the core tube is threadedly connected to the drill rod.

[0016] A method for operating equipment to prevent coal dust loss during coring of soft coal seams includes the following steps:

[0017] S1. Use a drilling rig, drill rod and drill bit to construct a sampling borehole. When the drilling reaches the predetermined sampling position, stop the drilling and remove the drill rod and drill bit.

[0018] S2. Connect the hollow drill bit, core tube, coal dust collection tank, and drill rod. Fix the drill rod on the drilling rig. Use the drilling rig and drill rod to push the hollow drill bit, core tube, and coal dust collection tank to the predetermined sampling position.

[0019] S3. After reaching the predetermined sampling position, start the drilling rig to drive the hollow drill bit to rotate and cut the coal sample. The coal sample enters the core tube and squeezes the closed blade in the anti-loss component. The closed blade is squeezed and rotates inward along the arc convex surface with the mounting shaft as the center. At the same time, the closed blade pushes the transmission rod to move downward. The transmission rod moves downward, stretches the spring, and drives the movable shaft to pull the movable gear to move downward along the fixed rack. The movable shaft drives the flexible baffle to move downward in the longitudinal opening through the avoidance hole on the flexible baffle. The flexible baffle moves along the four rotating shafts inside the protective cover. When the vertical limiting protrusion at the rear end of the closed blade rotates into the vertical limiting groove at the front end of the limiting block, the closed blade stops rotating inward, the anti-loss component is in the open state, and the coal sample enters the coal dust collection tank through the core tube.

[0020] S4. After coring is completed, the drill rod, hollow drill bit, coring tube, and coal dust collection tank are withdrawn by the drilling rig. When the coring tube leaves the predetermined sampling position, the spring contracts, and the traction transmission rod moves upward. The upward movement of the transmission rod drives the movable shaft to pull the movable gear to move upward along the fixed rack. The movable shaft drives the flexible baffle to move upward in the longitudinal opening through the clearance hole on the flexible baffle. The flexible baffle moves along four rotating shafts inside the protective cover. The closing blade is pushed by the transmission rod and rotates outward along the arc convex surface with the mounting shaft as the center. The vertical limiting protrusion at the rear end of the closing blade separates from the vertical limiting groove at the front end of the limiting block and returns to the initial position. At this time, the second vertical plane at the rear end of the closing blade abuts against the first vertical plane at the front end of the limiting block. The closing blade is in a horizontal state, the anti-loss component is closed, and the coal sample is sealed in the coring tube and the coal dust collection tank.

[0021] S5. After removing the drill rod, hollow drill bit, coring tube, and coal dust collection tank, separate the drill rod from the coal dust collection tank and remove the coring tube to obtain coal dust in the coal dust collection tank.

[0022] Compared with the prior art, the advantages and positive effects of this invention are:

[0023] During sampling, the hollow drill bit drills into the coal sample, pushing open the baffle mechanism in the anti-loss assembly, thus opening the anti-loss assembly. The coal sample passes through the core tube and enters the coal dust collection tank. After sampling, the drill rod, hollow drill bit, coal dust collection tank, and core tube are moved outward. Under the elastic action of the rebound mechanism in the anti-loss assembly, the baffle mechanism returns to its original state, closing the anti-loss assembly and achieving a sealing effect on the core tube and coal dust collection tank. This effectively prevents the loss of coal sample from the coal dust collection tank during drill rod withdrawal, improving the accuracy and efficiency of coal seam gas content testing.

[0024] On the other hand, the design of the lifting and sealing mechanism in the anti-loss component of this invention ensures that when the baffle mechanism drives the rebound mechanism, the bottom end of the transmission rod in the rebound mechanism moves smoothly under the action of the lifting and sealing mechanism, thus guaranteeing the movement stability of the transmission rod and improving the stability of the baffle mechanism during opening and closing. At the same time, the lifting and sealing mechanism is equipped with a flexible baffle to block the longitudinal opening for the longitudinal movement of the movable shaft, preventing coal dust from entering the lifting and sealing mechanism and hindering the longitudinal movement of the movable shaft, which would affect the service life of the anti-loss component. Furthermore, the flexible baffle can move longitudinally together with the movable shaft and the transmission rod, ensuring the sealing performance inside the lifting and sealing mechanism without hindering the longitudinal movement of the movable shaft and the transmission rod, further improving the effectiveness of this invention. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is an assembly structure diagram of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the present invention;

[0028] Figure 3 This is a structural diagram showing the connection between the hollow drill bit and the coal dust collection tank.

[0029] Figure 4 This is an assembly structure diagram of the core sampling tube and the anti-loss component;

[0030] Figure 5 This is a structural diagram of the anti-loss component;

[0031] Figure 6 This is a connection structure diagram of the baffle mechanism and the lifting sealing mechanism;

[0032] Figure 7 This is a schematic diagram of the limit stop block;

[0033] Figure 8 This is a schematic diagram of a closed blade.

[0034] Figure 9 This is an assembly structure diagram of the baffle mechanism;

[0035] Figure 10 This is a diagram showing the connection structure between the movable gear and the fixed rack in the lifting and sealing mechanism.

[0036] Figure 11 This is a diagram showing the connection structure between the flexible baffle and the rotating shaft in the lifting and sealing mechanism.

[0037] Figure 12 This is a diagram showing the connection structure between the flexible baffle and the sealing protrusion in the lifting and sealing mechanism. Detailed Implementation

[0038] 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.

[0039] like Figures 1 to 12 As shown, this embodiment discloses an apparatus for preventing coal dust loss during coring of soft coal seams, including a hollow drill bit 6, a coal dust collection tank 4, a core tube 1, and an anti-loss component 2. One axial end of the core tube 1 is threaded and threadedly connected to the hollow drill bit 6. The other axial end of the core tube 1 is also threaded and threadedly connected to one axial end of the coal dust collection tank 4. The other axial end of the coal dust collection tank 4 is threadedly connected to one end of the drill rod 5. The anti-loss component 2 is fixedly connected inside the core tube 1. A sealing cover 401 is provided on the inner wall of the end of the coal dust collection tank 4 away from the core tube 1. When the anti-loss component 2 is in the closed state, the anti-loss component 2, the core tube 1, and the coal dust collection tank 4 together form a sealed cavity structure for holding the collected coal sample. Figures 1-4 As shown.

[0040] The anti-loss component 2 includes four sets of baffle mechanisms 3, four sets of lifting and sealing mechanisms 8, and four sets of rebound mechanisms 7. The four sets of baffle mechanisms 3 are correspondingly arranged with the four sets of lifting and sealing mechanisms 8 and the four sets of rebound mechanisms 7. The lifting and sealing mechanism 8 is located below the baffle mechanism 3 and is connected to the baffle mechanism 3 through the rebound mechanism 7.

[0041] The four sets of baffle mechanisms 3 are arranged along the circumference of the core tube 1; each baffle mechanism 3 includes a limiting block 31 and a closing blade 32; one side wall of the limiting block 31 is arc-shaped and the arc end face is fixedly connected to the inner wall of the core tube 1; in the four sets of baffle mechanisms 3, the arc end faces of the four limiting blocks 31 are connected end to end and form a central area by the four limiting blocks 31; the end of the limiting block 31 away from the inner wall of the core tube 1 is pin-connected to the closing blade 32, and the closing blade 32 is triangular; in the four sets of baffle mechanisms 3, when the four closing blades 32 are in a horizontal state, they block and close the central area, such as Figure 5 , Figure 6 As shown;

[0042] like Figure 7 , Figure 8 As shown, the end face of the limiting block 31 away from the inner wall of the core tube 1 is set as a first vertical plane 311, and the bottom of the end of the limiting block 31 away from the inner wall of the core tube 1 is set as an arcuate convex surface 312. The top of the arcuate convex surface 312 is connected to the first vertical plane 311, and a vertical limiting groove 313 is provided at the bottom of the arcuate convex surface 312. The side of the vertical limiting groove 313 away from the arcuate convex surface 312 is set as a first inclined slope 314. The end face of the closing blade 32 near the limiting block 31 is set as a second vertical plane 323, and a vertical limiting protrusion 321 is provided at the bottom of the second vertical plane 323. The upper end face of the vertical limiting protrusion 321 is set as... An arc concave surface 322 is adapted to the arc convex surface 312. The top end of the arc concave surface 322 is connected to the second vertical plane 323. The lower end face of the vertical limiting protrusion 321 is set as the second inclined slope 324. When the closing blade 32 is in a horizontal state, the first vertical plane 311 and the second vertical plane 323 abut against each other. When the closing blade 32 is opened, the closing blade 32 rotates downward, and the arc convex surface 312 and the arc concave surface 322 generate sliding friction until the vertical limiting protrusion 321 is embedded in the vertical limiting groove 313 and the second inclined slope 324 abuts against the first inclined slope 314. At this time, the closing blade 32 is in a vertical state.

[0043] The limiting block 31 has a mounting groove 315 at the middle of the end face away from the inner wall of the core tube 1, and the closing blade 32 has a mounting protrusion 325 at the middle of the end face near the limiting block 31. The inner wall of the mounting groove 315 and the mounting protrusion 325 are respectively provided with a first pin hole 316 and a second pin hole 326. The mounting protrusion 325 is inserted into the mounting groove 315, and the first pin hole 316 and the second pin hole 326 are connected by a mounting shaft 33.

[0044] When the closed blade is in a horizontal or vertical state, the anti-loss component is in a closed or open state, respectively. The design of the first vertical plane and the second vertical plane allows the closed blade to remain flush with the upper surface of the limit block when it is in a horizontal state. The design of the vertical limit groove and the vertical limit protrusion ensures that the closed blade accurately stops rotating when it is in a vertical state, ensuring that the open state of the anti-loss component is not affected.

[0045] like Figure 5 , Figure 6 As shown, the rebound mechanism 7 includes a spring 72 and a transmission rod 71. The transmission rod 71 is inclined. The top end of the transmission rod 71 is connected to the bottom end of the closed blade 32 by a pin. The bottom end of the transmission rod 71 is connected to the lifting and sealing mechanism 8. The middle part of the transmission rod 71 is connected to the bottom end of the spring 72. The top end of the spring 72 is connected to the bottom end of the limiting block 31.

[0046] The lifting and sealing mechanism 8 includes a protective cover 81, a fixed rack 82, and a movable gear 83. The protective cover 81 is a rectangular cylindrical shell. The protective cover 81 is located below the limiting block 31, and its outer wall is fixedly connected to the inner wall of the core tube 1. The fixed rack 82 is fixedly connected to the inner wall of the protective cover 81 and is arranged longitudinally. The outer teeth of the movable gear 83 mesh with the teeth of the fixed rack 81. A movable shaft 84 is rotatably connected to the center of the movable gear 83 and is coaxial with the movable gear 83. One end of the movable shaft 84 is connected to the movable gear 83, and the other end of the movable shaft 84 passes through a longitudinal opening 811 on the side wall of the protective cover 81 and is connected to the bottom pin of the transmission rod 71. When the movable gear 83 rolls longitudinally along the fixed rack 82, the movable shaft 84 slides longitudinally within the longitudinal opening 811. Figure 5 , Figure 6 , Figure 10 As shown, Figure 10 This is a diagram showing the connection structure between the internal structure of the protective cover and the baffle mechanism. It is mainly for observing the connection structure between the fixed rack and the movable gear. In order to avoid the rotating shaft and flexible baffle in the internal structure of the protective cover from affecting the observation, the rotating shaft and flexible baffle in this figure are omitted.

[0047] When the closing blade flips inward, the bottom end of the transmission rod drives the movable shaft to move downward within the longitudinal opening. At the same time, the movable gear moves downward relative to the fixed rack under the meshing action of the teeth. When the closing blade returns to its original state, the transmission rod, movable shaft, and movable gear all move upward. The smooth lifting and lowering effect of the transmission rod and movable shaft is achieved through the meshing connection and movement of the gears and rack.

[0048] The protective cover 81 contains four rotating shafts 86, the axes of which are aligned with the width of the longitudinal opening 811. The four shafts 86 are located at the four corners of the protective cover 81, and both ends are rotatably connected to the inner wall of the protective cover 81. Flexible baffles 85 are fitted around the outer sides of the four shafts 86 and can rotate around them. One sidewall of the flexible baffle 85 is parallel to the sidewall of the protective cover 81 to which the longitudinal opening 811 belongs, and the flexible baffle 85 is located inside the longitudinal opening 811. A clearance hole 851 for connecting to a movable shaft 84 is provided on the side of the flexible baffle 85 closest to the longitudinal opening 811. When the movable shaft 84 is connected to the transmission rod 71, one end of the movable shaft 84 passes sequentially through the clearance hole 851 on the flexible baffle 85 and the longitudinal opening 811 on the sidewall of the protective cover 81, and then connects to one end of the transmission rod 71 via a pin. Figure 5 , Figure 6 , Figure 11 As shown, Figure 11 This is a longitudinal sectional view of the protective cover, mainly to observe the connection structure between the four rotating shafts and the flexible baffle. In order to avoid the fixed rack and movable gear in the internal structure of the protective cover from affecting the observation, the fixed rack and movable gear structure is omitted in this figure.

[0049] The protective cover 81 has two sealing protrusions 812 on the inner wall of one side of the longitudinal opening 811. The two sealing protrusions 812 are located on opposite sides of the width of the longitudinal opening 811. A sealing clearance groove 813 is provided on the side of the sealing protrusion 812 closest to the flexible baffle 85. The sealing clearance groove 813 helps to avoid and guide the movement of the flexible baffle 85. The two edges of the flexible baffle 85 in the width direction are embedded in the sealing clearance groove 813 and can slide longitudinally within the sealing clearance groove 813. Figure 12 As shown in the attached figure, this is a transverse sectional view of the protective cover, mainly to observe the connection structure between the sealing protrusion and the flexible baffle. At the same time, in order to avoid the fixed rack and movable gear in the internal structure of the protective cover from affecting the observation, the fixed rack and movable gear structure is omitted in this figure.

[0050] The flexible baffle can rotate and move under the action of four rotating shafts. When the movable shaft moves longitudinally within the longitudinal opening, it drives the flexible baffle to move longitudinally together under the action of the clearance hole. The rotating shaft and the sealing clearance groove both play a guiding and limiting role for the flexible baffle, allowing the flexible baffle to move easily while tightly fitting against the inner wall of the protective cover. This reduces the gap between the flexible baffle and the inner wall of the longitudinal opening, ensuring the sealing effect of the flexible baffle on the longitudinal opening. It prevents coal dust from entering the protective cover through the longitudinal opening and affecting the movement between the fixed rack and the movable gear, thus extending the service life of the anti-loss component and improving its effectiveness.

[0051] The specific working method of the above equipment is as follows:

[0052] S1. Use a drilling rig, drill rod 5 and drill bit to construct a sampling hole (upward hole, downward hole or parallel hole). When the construction reaches the predetermined sampling point, stop the construction and remove the drill rod 5 and drill bit.

[0053] S2. Connect the hollow drill bit 6 to the core tube 1. Connect the core tube 1 to the anti-loss component 2 and the coal dust collection tank 4 to form a core tube system. Connect the coal dust collection tank 4 to the drill rod 5. Fix the drill rod 5 on the drilling machine. Use the drilling machine to push the drill rod 5 and the core tube system into the borehole. Push the core tube system to the predetermined core sampling position by connecting the drill rods one by one.

[0054] S3. After reaching the predetermined sampling position, start the drilling machine to drive the hollow drill bit 6 to rotate and cut the coal sample. The coal sample enters the core tube 1 and squeezes the closed blade 32 in the anti-loss component 2. The closed blade 32 is squeezed and rotates inward along the arc convex surface 312 with the mounting shaft 33 as the center. At the same time, the closed blade 32 pushes the transmission rod 71 to move downward. The transmission rod 71 moves downward, stretches the spring 72 and drives the movable shaft 84 to pull the movable gear 83 to move downward along the fixed rack 82. The movable shaft 84 drives the flexible baffle 85 to move downward in the longitudinal opening 811 through the avoidance hole 851 on the flexible baffle 85. The flexible baffle 85 moves along the four rotating shafts 86 inside the protective cover 81. When the vertical limiting protrusion 321 at the rear end of the closed blade 32 rotates into the vertical limiting groove 313 at the front end of the limiting block 31, the closed blade 32 stops rotating inward, the anti-loss component 2 is in the open state, and the coal sample enters the coal dust collection tank 4 through the core tube 1.

[0055] S4. After core sampling is completed, the drill rods 5 and the core tube system are withdrawn one by one by the drilling rig. When the core tube 1 leaves the predetermined core sampling position, the spring 72 contracts, pulling the transmission rod 71 upward. The upward movement of the transmission rod 71 drives the movable shaft 84 to pull the movable gear 83 upward along the fixed rack 82. The movable shaft 84 drives the flexible baffle 85 to move upward within the longitudinal opening 811 through the clearance hole 851 on the flexible baffle 85. The flexible baffle 85 moves along the four rotating shafts 86 inside the protective cover 81. The closing blade 32 is pushed by the transmission rod 71 and rotates outward around the mounting shaft 33 along the arc convex surface 312. The vertical limiting protrusion 321 at the rear end of the closing blade 32 separates from the vertical limiting groove 313 at the front end of the limiting block 31, returning to the initial position. At this time, the second vertical plane 323 at the rear end of the closing blade 32 abuts against the first vertical plane 311 at the front end of the limiting block 31, the closing blade 32 is in a horizontal state, the anti-loss component 2 is closed, and the coal sample is sealed in the core tube 1 and the coal dust collection tank 4.

[0056] S5. After removing the drill rod 5 and the core tube system, separate the drill rod 5, the core tube 1 from the coal dust collection tank 4, and finally obtain the collected coal dust sample in the coal dust collection tank 4.

[0057] During sampling, the hollow drill bit drills into the coal sample, pushing open the baffle mechanism in the anti-loss assembly, thus opening the anti-loss assembly. The coal sample passes through the core tube and enters the coal dust collection tank. After sampling, the drill rod, hollow drill bit, coal dust collection tank, and core tube are moved outward. Under the elastic action of the rebound mechanism in the anti-loss assembly, the baffle mechanism returns to its original state, closing the anti-loss assembly and achieving a sealing effect on the core tube and coal dust collection tank. This effectively prevents the loss of coal sample from the coal dust collection tank during drill rod withdrawal, improving the accuracy and efficiency of coal seam gas content testing.

[0058] On the other hand, the design of the lifting and sealing mechanism in the anti-loss component of this invention ensures that when the baffle mechanism drives the rebound mechanism, the bottom end of the transmission rod in the rebound mechanism moves smoothly under the action of the lifting and sealing mechanism, thus guaranteeing the movement stability of the transmission rod and improving the stability of the baffle mechanism during opening and closing. At the same time, the lifting and sealing mechanism is equipped with a flexible baffle to block the longitudinal opening for the longitudinal movement of the movable shaft, preventing coal dust from entering the lifting and sealing mechanism and hindering the longitudinal movement of the movable shaft, which would affect the service life of the anti-loss component. Furthermore, the flexible baffle can move longitudinally together with the movable shaft and the transmission rod, ensuring the sealing performance inside the lifting and sealing mechanism without hindering the longitudinal movement of the movable shaft and the transmission rod, further improving the effectiveness of this invention.

Claims

1. An apparatus for preventing coal dust loss during coring of soft coal seams, comprising a hollow drill bit and a coal dust collection tank, wherein the hollow drill bit is connected to the coal dust collection tank; characterized in that: The equipment also includes a core tube and an anti-loss component; one axial end of the core tube is detachably connected to a hollow drill bit, and the other axial end of the core tube is detachably connected to one axial end of a coal dust collection tank, and the other axial end of the coal dust collection tank is detachably connected to one end of a drill rod; the anti-loss component is fixedly connected inside the core tube; the anti-loss component includes several sets of baffle mechanisms and several sets of lifting and sealing mechanisms, with the baffle mechanisms and lifting and sealing mechanisms corresponding to each other, the lifting and sealing mechanisms being located below the baffle mechanisms and connected to the baffle mechanisms via a spring-loaded mechanism; The lifting and sealing mechanism includes a protective cover, a fixed rack, and a movable gear. A movable shaft is rotatably connected to the center of the movable gear. One end of the movable shaft is connected to the movable gear, and the other end of the movable shaft passes through a longitudinal opening on the side wall of the protective cover and is connected to a pin at one end of the transmission rod in the spring mechanism. Four rotating shafts are provided inside the protective cover. Flexible baffles are sleeved on the outside of the four rotating shafts and can rotate around the four rotating shafts. The movable shafts can drive the flexible baffles to move longitudinally together.

2. The equipment for preventing coal dust loss during coring of soft coal seams as described in claim 1, characterized in that: The baffle mechanism comprises four sets arranged along the circumference of the core tube. Each baffle mechanism includes a limiting block and a closing blade. One side wall of the limiting block is arc-shaped and its arc end face is fixedly connected to the inner wall of the core tube. In the four sets of baffle mechanisms, the arc end faces of the four limiting blocks are connected end to end and enclose a central area. The end of the limiting block away from the inner wall of the core tube is connected to the closing blade pin, and the closing blade is triangular in shape. In the four sets of baffle mechanisms, the four closing blades block and close the central area when in a horizontal state.

3. The equipment for preventing coal dust loss during coring of soft coal seams as described in claim 2, characterized in that: The end face of the limiting block away from the inner wall of the core tube is set as a first vertical plane, and the bottom of the end of the limiting block away from the inner wall of the core tube is set as a convex arc surface. The top of the convex arc surface is connected to the first vertical plane, and a vertical limiting groove is provided at the bottom of the convex arc surface. The end face of the closing blade near the limiting block is set as a second vertical plane, and a vertical limiting protrusion is provided at the bottom of the second vertical plane. The upper end face of the vertical limiting protrusion is set as a concave arc surface that matches the convex arc surface, and the top of the concave arc surface is connected to the second vertical plane. When the closing blade is in a horizontal state, the first vertical plane and the second vertical plane abut against each other. When the closing blade is opened, the closing blade rotates downward, and the convex arc surface and the concave arc surface generate sliding friction until the vertical limiting protrusion is embedded in the vertical limiting groove. At this time, the closing blade is in a vertical state.

4. The equipment for preventing coal dust loss during coring of soft coal seams as described in claim 3, characterized in that: The limiting block has an installation groove in the middle of the end face away from the inner wall of the core tube, and the closing blade has an installation protrusion in the middle of the end face near the limiting block. The installation protrusion is inserted into the installation groove and the installation protrusion and the installation groove are connected by an installation pin.

5. The equipment for preventing coal dust loss during coring of soft coal seams as described in claim 4, characterized in that: The rebound mechanism includes a spring and a transmission rod. One end of the transmission rod is connected to the bottom pin of the closed blade, and the other end of the transmission rod is connected to the lifting and sealing mechanism. The middle part of the transmission rod is connected to one end of the spring, and the other end of the spring is connected to the bottom of the limiting block.

6. The equipment for preventing coal dust loss during coring of soft coal seams as described in claim 5, characterized in that: The protective cover is in the shape of a rectangular column shell. The protective cover is located below the limiting block and is fixedly connected to the inner wall of the core tube. A fixed rack is fixedly connected to the inner wall of the protective cover and is arranged longitudinally. The outer teeth of the movable gear mesh with the teeth of the fixed rack. The movable shaft is coaxial with the movable gear. When the movable gear rolls longitudinally along the fixed rack, the movable shaft slides longitudinally within the longitudinal opening.

7. The equipment for preventing coal dust loss during coring of soft coal seams as described in claim 6, characterized in that: The axial direction of the four rotating shafts is consistent with the width direction of the longitudinal opening. The four rotating shafts are distributed at the four corner positions of the protective cover, and both ends of the rotating shafts are rotatably connected to the inner wall of the protective cover. One side wall of the flexible baffle is parallel to the side wall of the protective cover to which the longitudinal opening belongs, and the flexible baffle is located inside the longitudinal opening. The side of the flexible baffle near the longitudinal opening is provided with a clearance hole for connecting to the movable shaft. When the movable shaft is connected to the transmission rod, one end of the movable shaft passes through the clearance hole on the flexible baffle and the longitudinal opening of the side wall of the protective cover in sequence, and then connects to one end of the transmission rod with a pin.

8. The equipment for preventing coal dust loss during coring of soft coal seams as described in claim 7, characterized in that: The protective cover has two sealing protrusions on the inner wall of the side with the longitudinal opening. The two sealing protrusions are located on both sides of the width direction of the longitudinal opening. A sealing clearance groove is provided on the side of the sealing protrusion near the flexible baffle, and the sealing clearance groove avoids the movement of the flexible baffle.

9. The equipment for preventing coal dust loss during coring of soft coal seams as described in claim 8, characterized in that: The two ends of the coring tube are threadedly connected to the hollow drill bit and the coal dust collection tank, respectively. The inner wall of the coal dust collection tank away from the coring tube is provided with a sealing cap, and the end of the coal dust collection tank away from the coring tube is threadedly connected to the drill rod.

10. A method for operating the equipment as described in claim 9 for preventing coal dust loss during coring of soft coal seams, characterized in that: Includes the following steps: S1. Use a drilling rig, drill rod and drill bit to construct a sampling borehole. When the drilling reaches the predetermined sampling position, stop the drilling and remove the drill rod and drill bit. S2. Connect the hollow drill bit, core tube, coal dust collection tank, and drill rod. Fix the drill rod on the drilling rig. Use the drilling rig and drill rod to push the hollow drill bit, core tube, and coal dust collection tank to the predetermined sampling position. S3. After reaching the predetermined sampling position, start the drilling rig to drive the hollow drill bit to rotate and cut the coal sample. The coal sample enters the core tube and squeezes the closed blade in the anti-loss component. The closed blade is squeezed and rotates inward along the arc convex surface with the mounting shaft as the center. At the same time, the closed blade pushes the transmission rod to move downward. The transmission rod moves downward, stretches the spring, and drives the movable shaft to pull the movable gear to move downward along the fixed rack. The movable shaft drives the flexible baffle to move downward in the longitudinal opening through the avoidance hole on the flexible baffle. The flexible baffle moves along the four rotating shafts inside the protective cover. When the vertical limiting protrusion at the rear end of the closed blade rotates into the vertical limiting groove at the front end of the limiting block, the closed blade stops rotating inward, the anti-loss component is in the open state, and the coal sample enters the coal dust collection tank through the core tube. S4. After coring is completed, the drill rod, hollow drill bit, coring tube, and coal dust collection tank are withdrawn by the drilling rig. When the coring tube leaves the predetermined sampling position, the spring contracts, and the traction transmission rod moves upward. The upward movement of the transmission rod drives the movable shaft to pull the movable gear to move upward along the fixed rack. The movable shaft drives the flexible baffle to move upward in the longitudinal opening through the clearance hole on the flexible baffle. The flexible baffle moves along four rotating shafts inside the protective cover. The closing blade is pushed by the transmission rod and rotates outward along the arc convex surface with the mounting shaft as the center. The vertical limiting protrusion at the rear end of the closing blade separates from the vertical limiting groove at the front end of the limiting block and returns to the initial position. At this time, the second vertical plane at the rear end of the closing blade abuts against the first vertical plane at the front end of the limiting block. The closing blade is in a horizontal state, the anti-loss component is closed, and the coal sample is sealed in the coring tube and the coal dust collection tank. S5. After removing the drill rod, hollow drill bit, coring tube, and coal dust collection tank, separate the drill rod from the coal dust collection tank and remove the coring tube to obtain coal dust in the coal dust collection tank.

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