A downhole coal seam gas fixed-point sampling device

Abstract

The present application belongs to the technical field of coal mine gas disaster prevention and control, and particularly relates to an underground coal seam gas fixed-point sampling device, which comprises a standard drill rod combination and a sampling drill rod installed at the end or middle of the standard drill rod combination, a side wall of the planing knife mouth smooth drill rod is provided with a sampling port, and a sliding sliding door mechanism and a crank baffle mechanism are installed at the sampling port, and an anti-throwing-out sampling cylinder is installed in the planing knife mouth smooth drill rod. The present application has a reasonable structure design, and the coal sample collection is carried out in a closed environment, so that the escape of the gas content in the coal sample is avoided. Thus, the sum of the coal sample field gas desorption amount and the coal sample residual gas desorption amount determined in the laboratory is calculated to obtain the coal sample gas content. The coal sample collection device is simple to operate, has strong applicability, is simple to maintain, safe and efficient, realizes the collection of the coal sample while drilling with the drill rod, and can ensure that the coal sample is in a closed state during the collection process, avoids the loss of the gas in the coal sample, and effectively improves the accuracy of the coal mine underground gas condition detection.

Description

Technical Field

[0001] This invention belongs to the field of coal mine gas disaster prevention and control technology, specifically relating to a fixed-point sampling device for underground coal seam gas. Background Technology

[0002] Coal mine gas accidents occur frequently. During coal mining, the immaturity of gas pressure-maintaining and leakage-prevention technologies leads to significant discrepancies between laboratory gas content measurements and actual underground gas content. This affects the accuracy of subsequent coal mine gas control and gas resource assessment data. Furthermore, gas outbursts are crucial for prevention and prediction, as a certain gas content can trigger an outburst. Since 2009, the "Prevention of Coal and Gas Outbursts" standard has been implemented, imposing strict requirements on the mining of coal seams prone to gas outbursts. However, the situation regarding coal and gas outburst disaster prevention remains severe, with frequent accidents. Therefore, the technology of precise measurement of coal seam gas content through fixed-point pressure-maintaining sampling is of great significance for improving the exploration and development of coalbed methane resources and the level of coal mine gas disaster control.

[0003] The existing technologies for fixed-point drill cuttings sampling and gas pressure maintenance and leakage prevention mainly have the following problems: 1) Drilling, sampling and testing cannot be carried out simultaneously; 2) The sampling depth is shallow and deep coal samples cannot be obtained; 3) The sampling time is long, the airtightness of the device is poor, and the amount of gas leakage during the sampling process is large; 4) The sample volume is small, making it difficult to accurately detect the gas concentration of the coal sample; 5) It is difficult to achieve precise fixed-point sampling, and coal samples from different locations are seriously mixed.

[0004] The above reasons lead to inaccurate gas content measurements, affecting the objective assessment of gas hazard levels and subsequent prevention and control measures. Summary of the Invention

[0005] The purpose of this invention is to overcome the aforementioned problems in traditional technologies and to provide a fixed-point sampling device for underground coal seam gas.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0007] A fixed-point sampling device for coal seam gas in underground mines includes a standard drill rod assembly and a sampling drill rod installed at its end or middle. The sampling drill rod consists of a planer-edge smooth drill rod and drill rod connecting female heads and drill rod connecting female heads installed at its two ends. The side wall of the planer-edge smooth drill rod has a sampling port, and a sliding door mechanism and a crank door mechanism are installed at the sampling port. An anti-throw-out sampling cylinder is installed inside the planer-edge smooth drill rod.

[0008] In this embodiment, the sampling drill rod is equipped with an air pipe that communicates with the ventilation holes inside the standard drill rod on the front and / or rear sides, facilitating the injection of jet airflow to expel coal dust from the borehole during drill rod excavation; a valve core-type air intake port that communicates with the air pipe is installed on the pipe wall of the sampling drill rod; after sampling is completed and the entire machine structure is removed and emptied, an air intake pipe connector is connected to this air intake port to ensure that not too much gas is leaked during the extraction of methane gas on the ground at the end of sampling; the air pipe is equipped with a vent on the pipe body inside the anti-throw-out sampling cylinder.

[0009] In this embodiment, a certain amount of air pipe space is reserved inside the sampling drill pipe section, and the specific air pipe size is determined based on computer simulation and laboratory experimental measurement. This size ensures that the drill pipe as a whole can smoothly receive the jet airflow during drilling to remove coal dust that hinders drilling and to ensure the jet airflow. This size ensures that it will not affect other internal structures of the sampling drill pipe.

[0010] In this embodiment, the sliding door mechanism includes a cover plate, a motor cylinder, a DC servo motor, a motor frame, a coupling, a screw, a movable nut, and a sliding door. Both ends of the cover plate are fixed to the inner wall of the planer blade's smooth drill rod via supports. The cover plate is fixed to the DC servo motor via the motor cylinder and motor frame. The output shaft of the DC servo motor is fixed to one end of the screw via a coupling. A bearing seat is installed on the cover plate to provide rotational support for the other end of the screw. A movable nut is fitted onto the outer side of the screw for engagement. A sliding door is installed on the movable nut. The sliding door is positioned against the inner area of ​​the sampling port, and its opening and closing can be controlled by sliding.

[0011] In this embodiment, the crank door mechanism includes a hinge, a crank door, and a crank connecting rod. The hinge is installed at the sampling port. One end of the crank door is rotatably connected to the smooth drill rod of the planer blade via the hinge, and the other end is connected to the sliding door via the crank connecting rod.

[0012] In this embodiment, the anti-throw-out sampling cylinder includes a sampling cylinder, a baffle, and a baffle spring. The sampling cylinder has a guide port near the sampling port. A rotatable baffle is installed on the inner side of the guide port. A positioning shaft that provides rotational support is installed in the middle of the baffle. The side wall of the sampling cylinder has symmetrically opened positioning grooves that cooperate with the positioning shaft. A baffle spring is installed between the baffle and the sampling cylinder at the end away from the guide port.

[0013] In this embodiment, when sampling begins, the sliding door drives the crank door to open, preventing coal dust in the sampling hole from moving to the rear of the sampling port, causing a large amount of coal sample to accumulate on the baffle and pushing the coal sample into the sampling cylinder; when sampling is completed, the sliding door drives the crank door to close, pushing the coal dust still accumulated on the baffle into the sampling cylinder and squeezing it into the upper space of the anti-throw-out sampling cylinder, increasing the sampling amount.

[0014] In this embodiment, the smooth drill rod with planer blade has a control chip and battery with an integrated remote control module installed inside;

[0015] The baffle is equipped with a position sensor that can identify the baffle's flip angle;

[0016] The inner wall of the sampling tube is equipped with a patch-type temperature sensor, humidity sensor, and pressure sensor.

[0017] The position sensor, temperature sensor, humidity sensor, pressure sensor, and DC servo motor are all connected to the control chip of the integrated remote control module.

[0018] In this embodiment, the sliding door is machined with concave grooves around its perimeter, and the sampling port is fitted with a raised rubber sealing strip at the corresponding position; a brush is installed on the sliding door, and when the sampling drill rod reaches the designated position, the brush moves accordingly when the sliding door is opened, which can displace the coal dust adhering to the outside of the sampling drill rod tube wall.

[0019] In this embodiment, the sampling tube uses part of the cover plate and the support connected to the cover plate as the components of its own tube body. When the sliding door closes the sampling port, it also closes the sample guide port of the sampling tube. At this time, the inner cavity of the sampling tube is in a completely sealed state.

[0020] The beneficial effects of this invention are:

[0021] This invention features a reasonable structural design, with coal sample collection conducted in a closed environment, preventing the escape of gas content from the coal sample. The gas content of the coal sample is calculated by summing the on-site gas desorption amount and the laboratory-measured residual gas desorption amount. Furthermore, this coal sample collection device is simple to operate, highly applicable, easy to maintain, safe, and efficient. It enables coal sample collection while drilling, ensuring the sample remains sealed during collection, preventing gas loss and effectively improving the accuracy of underground gas detection in coal mines.

[0022] Of course, any product implementing this invention does not necessarily need to achieve all of the above advantages at the same time. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments 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.

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the planer blade cross-section of the smooth drill rod in this invention;

[0026] Figure 3 This is a schematic diagram of the crank door structure in this invention;

[0027] Figure 4 This is a schematic diagram illustrating the working principle of the crank door in this invention;

[0028] Figure 5 This is a schematic diagram of the crank door mechanism in this invention;

[0029] Figure 6 This is a schematic diagram illustrating the working principle of the upper baffle of the anti-splash sampling cylinder in this invention.

[0030] Figure 7 This is a schematic diagram of the structure of the upper baffle of the anti-splash sampling cylinder in this invention;

[0031] In the attached diagram, the component numbers are as follows:

[0032] 1- Drill rod connecting head, 2- Smooth drill rod with planer blade, 3- Motor cylinder, 4- Battery, 5- DC servo motor, 6- Motor frame, 7- Coupling, 8- Screw, 9- Movable nut, 10- Sliding door, 11- Bearing seat, 12- Sampling cylinder, 13- Vent port, 14- Hinge, 15- Crank door, 16- Crank connecting rod, 17- Baffle, 18- Baffle spring, 19- Cover plate, 20- Drill rod connecting head. Detailed Implementation

[0033] 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, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] like Figures 1-7As shown, this embodiment provides a fixed-point sampling device for coal seam gas in underground mines, including a standard drill rod assembly and a sampling drill rod installed at its end or middle. The sampling drill rod consists of a planer-edge smooth drill rod 2 and drill rod connecting female head 1 and drill rod connecting female head 20 respectively installed at its two ends. The side wall of the planer-edge smooth drill rod 2 is provided with a sampling port, and a sliding door mechanism and a crank door mechanism are installed at the sampling port. An anti-throw-out sampling cylinder is installed inside the planer-edge smooth drill rod.

[0035] In this embodiment, the sampling drill rod is equipped with an air pipe that communicates with the ventilation holes inside the standard drill rod on the front and / or rear sides. This facilitates the injection of jet gas during drill pipe excavation to expel coal dust from the borehole. A valve-type air intake port, connected to the air pipe, is installed on the pipe wall of the sampling drill rod. After sampling is completed and the entire machine structure is removed and emptied, an air intake pipe connector is connected to this air intake port to ensure that minimal gas leakage occurs during the extraction of methane gas from the surface at the end of sampling. A vent 13 is provided on the pipe body inside the anti-ejection sampling cylinder. A certain amount of space is reserved inside the sampling drill rod section for the air pipe, and the specific air pipe dimensions are determined based on computer simulation and laboratory experimental measurements. These dimensions ensure that the entire drill rod can unobstructedly receive jet gas during drilling to expel coal dust that hinders drilling and to ensure sufficient jet gas flow. These dimensions also ensure that the sampling drill rod's internal structure will not be affected.

[0036] In this embodiment, the sliding door mechanism includes a cover plate 19, a motor cylinder 3, a DC servo motor 5, a motor frame 6, a coupling 7, a screw 8, a movable nut 9, and a sliding door 10. Both ends of the cover plate 19 are fixed to the inner wall of the planer-edge smooth drill rod 2 via supports. The cover plate 19 is fixed to the DC servo motor 5 via the motor cylinder 3 and the motor frame 6. The output shaft of the DC servo motor 5 is fixed to one end of the screw 8 via the coupling 7. A bearing seat 11 is installed on the cover plate 19 to provide rotational support for the other end of the screw 8. A movable nut 9 is fitted onto the outer side of the screw 8 for engagement. The sliding door 10 is installed on the movable nut 9 and is positioned against the inner area of ​​the sampling port. Sliding allows for the opening and closing control of the inner port of the sampling port.

[0037] In this embodiment, the crank door mechanism includes a hinge 14, a crank door 15, and a crank connecting rod 16. The hinge 14 is installed at the sampling port. One end of the crank door 15 is rotatably connected to the smooth drill rod 2 of the planer blade via the hinge 14, and the other end is connected to the sliding door 10 via the crank connecting rod 16. When sampling begins, the sliding door 10 drives the crank door 15 to open, preventing coal dust in the sampling hole from moving to the rear of the sampling port, causing a large amount of coal sample to accumulate on the baffle 17, and pushing the coal sample into the sampling cylinder 12. When sampling is completed, the sliding door 10 drives the crank door 15 to close, pushing the coal dust still accumulated on the baffle 17 into the interior of the sampling cylinder 12, squeezing into the upper space of the anti-throw-out sampling cylinder, increasing the sampling volume.

[0038] In this embodiment, the anti-throw-out sampling cylinder includes a sampling cylinder 12, a baffle 17, and a baffle spring 18. The sampling cylinder 12 is provided with a sample guide port near the sampling port. A baffle 17 that can be rotated and opened is installed in the inner area of ​​the sample guide port. A positioning shaft that provides rotational support is installed in the middle of the baffle 17. Positioning grooves that cooperate with the positioning shaft are symmetrically opened on the side wall of the sampling cylinder 12. A baffle spring 18 is installed between the baffle 17 and the sampling cylinder 12 at the end away from the sample guide port.

[0039] In this embodiment, the smooth drill rod 2 with planer blade has an integrated remote control module control chip and a battery 4 installed inside. The battery 4 is fixedly installed on a support connected to one end of the cover plate 19. A position sensor capable of identifying the baffle flip angle is installed on the baffle 17. A patch-type temperature sensor, humidity sensor, and pressure sensor are installed on the inner wall of the sampling cylinder 12. The position sensor, temperature sensor, humidity sensor, pressure sensor, and DC servo motor are all connected to the control chip of the integrated remote control module.

[0040] In this embodiment, concave grooves are machined around the upper perimeter of the sliding door 10, and a raised rubber sealing strip is installed at the corresponding position of the sampling port; a brush is installed on the sliding door 10, and when the sampling drill rod reaches the designated position, the brush on it moves with the sliding door, which can displace the coal dust attached to the outside of the sampling drill rod tube wall.

[0041] In this embodiment, the sampling cylinder 12 uses part of the cover plate 19 and the support connected to the cover plate as the components of its own cylinder. When the sliding door 10 closes the sampling port, it also closes the sample guide port of the sampling cylinder 12. At this time, the inner cavity of the sampling cylinder is in a completely sealed state.

[0042] The specific sampling process of this invention is as follows:

[0043] Install the drilling rig, air filling equipment, and external electrical system for drilling on the ground. Assemble the corresponding number of drill rods to the specified length as required. The last section is the sampling device provided in this embodiment, namely the sampling drill rod section. Then, install the drilling bit at the very top.

[0044] Turn on the drilling rig and begin drilling. At the same time, turn on the air supply equipment to circulate air into the pipe, ensuring that the drilling speed is high and the air supply intensity is high.

[0045] Once a set number of drill rods have been inserted into the borehole, the sampling drill rod section is controlled by a transmission wire wound around the surface of each drill rod.

[0046] Once the sampling drill rod reaches the designated sampling depth, the DC servo motor 5 inside the remotely controlled sampling drill rod begins to rotate, while simultaneously controlling the drilling speed of the drill to a low speed and reducing the inflation intensity of the air inflation device.

[0047] The DC servo motor 5 is powered by a storage battery also placed inside the sampling drill rod. The rotation of the motor shaft drives the coupling 7 connected to the motor shaft to rotate, which in turn drives the screw 8 at the other end of the coupling to start rotating. At the same time, the drilling speed of the drill is controlled to become a low speed state, and the inflation intensity of the air inflation device is weakened. One end of the screw 8 is connected to the coupling 7, and the other end is fixed in the bearing seat 11 equipped with an angular contact bearing. When the screw 8 starts to rotate, the movable nut 9 on it drives the sliding door 10 to move linearly.

[0048] The sliding door 10 is opened to fully expose the sampling port and the sample guide port. The crank connecting rod 16 connected to the outside of the sliding door 10 drives the crank door 15 to rotate. One end of the crank door 15 is connected to the rotating pair of the crank connecting rod 16, and the other end is connected to the hinge 14. The hinge 14 is installed on the outer wall of the smooth drill rod and acts as a rotating pair to realize the rotation of the crank door 15.

[0049] The crank door 15 is inclined at an angle of about 30° to the wall of the sampling cylinder and pushes away the coal dust that was previously attached to other positions on the surface of the drill rod. At the same time, the sliding door 10 is equipped with a brush of a certain length. When the sampling drill rod reaches the designated position, the sliding door 10 is opened. At this time, the brush on the sliding door 10 moves and pushes away the coal dust that was previously attached to the outside of the sampling drill rod tube wall.

[0050] At this point, the drilling speed remains low and the air filling intensity is weak, and drilling continues. As drilling continues, the coal cuttings at this location will be broken up by the drill bit. Then, due to the obstruction of the crank door 15, a large amount of coal sample accumulates on the baffle 17 and pushes the coal sample into the sampling cylinder 12.

[0051] After the coal sample enters the sampling cylinder 12, it hits the baffle 17 and enters the sampling cylinder 12. During the drilling and sampling process, the centrifugal force generated by the rotating drilling action prevents the coal sample inside the sampling cylinder 12 from being thrown out of the sampling port and continuing to accumulate coal dust inside the sampling cylinder 12. A position sensor is installed on the baffle 17. When the position sensor detects that the baffle has flipped to a certain angle, it can be considered that the sampling action has been completed. At this time, the control chip controls the DC servo motor 5 to close the sampling port using the sliding door 10. The sliding door 10 simultaneously drives the crank door 15 to close, sealing and blocking the sampling port.

[0052] A concave groove is machined around the sliding door 10, and a raised rubber sealing strip is installed at the position corresponding to the sampling port to achieve the sealing of the sampling cylinder 12; after the sliding door 10 is completely closed, the entire structure operation ends, and the surface-mount temperature sensor, humidity sensor and pressure sensor inside the sampling cylinder 12 are activated. The control chip communicates remotely with the back-end terminal through the remote control module to realize remote monitoring of the coal sample and natural gas inside the sampling cylinder 12.

[0053] Once the necessary data collection is complete, the entire sampling drill pipe is removed, and the natural gas inside the pipe is collected through the gas sampling pipe joint on one side of the pipe wall.

[0054] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A fixed-point sampling device for underground coal seam gas, characterized in that: It includes a standard drill rod assembly and a sampling drill rod installed at its end or middle. The sampling drill rod consists of a planer-edge smooth drill rod and drill rod connecting female head and drill rod connecting female head installed at both ends. The side wall of the planer-edge smooth drill rod has a sampling port, and a sliding door mechanism and a crank baffle mechanism are installed at the sampling port. The inside of the planer-edge smooth drill rod is equipped with an anti-throw-out sampling cylinder. The sliding door mechanism includes a cover plate, a motor cylinder, a DC servo motor, a motor frame, a coupling, a screw, a movable nut, and a sliding door. The two ends of the cover plate are fixed to the inner wall of the planer blade smooth drill rod by supports. The cover plate is fixed with the DC servo motor by the motor cylinder and the motor frame. The output shaft of the DC servo motor is fixed to one end of the screw by the coupling. The cover plate is equipped with a bearing seat that provides rotational support for the other end of the screw. The outer side of the screw is fitted with a meshing movable nut. The movable nut is installed on the movable nut. The sliding door is set against the inner area of ​​the sampling port. The opening and closing of the inner port of the sampling port can be controlled by sliding. The crank baffle mechanism includes a hinge, a crank door, and a crank connecting rod. The hinge is installed at the sampling port. One end of the crank door is rotatably connected to the smooth surface drill rod of the planer blade via the hinge, and the other end is connected to the sliding door via the crank connecting rod. The anti-throw-out sampling cylinder includes a sampling cylinder, a baffle, and a baffle spring. The sampling cylinder has a sample guide port near the sampling port. A rotatable baffle is installed in the inner area of ​​the sample guide port. A positioning shaft that provides rotational support is installed in the middle of the baffle. The side wall of the sampling cylinder has symmetrically opened positioning grooves that cooperate with the positioning shaft. A baffle spring is installed between the baffle and the sampling cylinder at the end away from the sample guide port. When sampling begins, the sliding door opens the crank door, preventing coal dust from moving to the back of the sampling port, causing a large amount of coal sample to accumulate on the baffle and pushing the coal sample into the sampling cylinder; when sampling is completed, the sliding door closes the crank door, pushing the coal dust still accumulated on the baffle into the sampling cylinder and squeezing it into the upper space of the anti-throw-out sampling cylinder, increasing the sampling volume.

2. The underground coal seam gas fixed-point sampling device according to claim 1, characterized in that: The sampling drill rod is equipped with an air pipe that communicates with the ventilation holes inside the standard drill rod on the front and / or rear sides, facilitating the injection of jet airflow to expel coal dust from the borehole during drill rod excavation. A valve core-type air intake port connected to the air pipe is installed on the pipe wall of the sampling drill rod. After sampling is completed and the entire machine structure is removed and emptied, an air intake pipe connector is connected to this air intake port to ensure that not too much gas leaks during the extraction of methane gas on the ground at the end of sampling. The air pipe is equipped with a vent on the pipe body inside the anti-throw-out sampling cylinder.

3. The underground coal seam gas fixed-point sampling device according to claim 2, characterized in that: A certain amount of air pipe space is reserved inside the sampling drill pipe section, and the specific air pipe size is determined based on computer simulation and laboratory experimental measurement. This size ensures that the drill pipe as a whole can be unobstructed to receive the jet airflow during drilling, so as to remove coal cuttings that hinder drilling and ensure the jet airflow. This size ensures that it will not affect other internal structures of the sampling drill pipe.

4. The underground coal seam gas fixed-point sampling device according to claim 1, characterized in that: The smooth drill rod with a planer blade has a control chip and battery installed inside that integrate a remote control module. The baffle is equipped with a position sensor that can identify the baffle's flip angle; The inner wall of the sampling tube is equipped with a patch-type temperature sensor, humidity sensor, and pressure sensor. The position sensor, temperature sensor, humidity sensor, pressure sensor, and DC servo motor are all connected to the control chip of the integrated remote control module.

5. The underground coal seam gas fixed-point sampling device according to claim 4, characterized in that: The sliding door is machined with concave grooves around its perimeter, and the sampling port is fitted with a raised rubber sealing strip at the corresponding position. A brush is installed on the sliding door, and when the sampling drill rod reaches the designated position, the brush moves accordingly when the sliding door is opened, which can displace the coal dust adhering to the outside of the sampling drill rod tube wall.

6. The underground coal seam gas fixed-point sampling device according to claim 5, characterized in that: The sampling tube utilizes part of the cover plate and the support connected to the cover plate as its own body. When the sliding door closes the sampling port, it also closes the sample guide port of the sampling tube. At this time, the inner cavity of the sampling tube is in a completely sealed state.

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