Telescopic closed sampling device and use method

Abstract

The invention relates to a telescopic closed sampling device which is characterized by comprising a drill bit, a sampling mandrel, a device shell and an elastic short section, one end of the sampling mandrel is connected with the drill bit, and the other end of the sampling mandrel is connected with the elastic short section; a sampling cavity is formed in the middle of the sampling mandrel; three limiting pins and a limiting guide rail are arranged on the inner wall of the middle part of the device shell; two limiting grooves matched with the limiting pins are formed in the outer wall of the middle part of the sampling mandrel; a limiting ring is arranged on the outer wall of the end, close to the elastic short section, of the sampling mandrel, a limiting foot is arranged on the limiting ring, and the limiting foot slides in the limiting guide rail; sealing rings are arranged at the two ends of the sampling mandrel. Sampling is carried out through a self-designed action mode, the closed structure ensures that the sampled coal sample is in a closed state, the purpose of closed sampling while drilling of an underground common drilling machine is achieved, and the sampling device has the advantages of being good in sampling effect and convenient and fast to operate.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mine safety, and relates to a telescopic airtight sampling device and a using method thereof. Background Technique

[0002] With the continuous increase in the depth of coal mining, the mining of deep coal seams faces increasingly complex geological conditions and safety challenges. The significant increase in gas pressure, gas content, and in-situ stress has greatly enhanced the risk of coal and gas outburst. As a serious mine disaster, coal and gas outburst not only threatens the lives of miners but also has a significant impact on the production efficiency and economic benefits of the mine. Therefore, accurately predicting and effectively preventing and controlling coal and gas outburst disasters has become one of the core research topics in deep coal mining technology. According to relevant national regulations and industry standards, in the prediction of regional outburst danger and the inspection of the effect of regional outburst prevention measures, the determination of coal seam gas content and residual gas content is a key link, and these determination works must adopt the fixed-point sampling method to ensure the accuracy and reliability of the data. However, there are still many deficiencies in the current fixed-point sampling technology and equipment in the coal industry, and the limitations of technical means have restricted the efficiency and accuracy of gas content determination work to a certain extent.

[0003] At present, the fixed-point sampling technologies widely used in the coal industry mainly include air reverse circulation sampling technology and airtight coring technology. Each of these two technologies has its own characteristics, but some problems that need to be solved urgently have also emerged in practical applications. The air reverse circulation sampling technology is a relatively mature sampling method. Its basic principle is to carry out drilling construction through double-wall drill pipes and special drill bits. In the sampling stage, by changing the air inlet and outlet channels inside the drill pipe, a negative pressure is generated by the ejector behind the drill bit, so that the pulverized coal is returned out of the borehole along with the air flow through the inside of the drill pipe, thereby realizing the collection of coal samples. This technology has the advantages of simple principle, convenient construction, and relatively low equipment cost, and is widely used in various coal seam sampling scenarios. However, in actual operation, the application effect of the air reverse circulation sampling technology is restricted by various factors. First of all, the strength and sealing performance of the double-wall drill pipe directly affect the stability of the sampling process. If the drill pipe strength is insufficient or the sealing performance is poor, it may lead to air leakage or blockage of the sampling channel, thereby reducing the sampling success rate. Secondly, the hardness and particle characteristics of coal samples will also have a significant impact on the sampling effect. For coal seams with high hardness or uneven particles, it is difficult for the ejector to effectively extract pulverized coal, resulting in insufficient sampling volume or insufficient sample representativeness. In addition, in the high gas pressure environment of deep coal seams, the air reverse circulation sampling technology may cause safety hazards due to improper air flow control, such as gas leakage or local accumulation, further increasing the construction risk.

[0004] In contrast, the closed coring technology is a more advanced sampling method. Its core lies in transforming the conventional coring tube and developing a closed coring device with a sealing function, so as to ensure that the coal sample is in a completely sealed state during the sampling process, avoiding the escape of gas or the pollution of the sample by external air. This technology can theoretically significantly improve the accuracy of gas content measurement, especially suitable for high-gas coal seams and deep mining environments. The design of the closed coring device is the key to this technology. Its main function is to quickly seal the coring channel through the internal sealing mechanism after sampling to prevent the sample from contacting the external environment. At present, the common closed coring devices on the market mostly adopt the valve control method, and the sampling and sample sealing are achieved through the opening and closing of the valve. However, this design has some inherent defects in practical applications. First, the reliability of the valve action is an important factor affecting the sampling effect. Under complex geological conditions, such as high in-situ stress or high gas pressure environments, the valve may fail due to mechanical wear, impurity blockage or pressure shock, resulting in sampling failure or poor sample sealing. Second, during the use of the closed coring device while drilling, the coring channel is easily blocked by coal powder or other impurities. This blockage phenomenon not only reduces the sampling efficiency but also may cause the coring device to malfunction, and even lead to equipment damage. In addition, the existing closed coring devices have complex structures, high manufacturing costs, and high requirements for the professional skills of technicians in on-site operations, which to a certain extent limits the popularization and application of this technology in grass-roots mines.

[0005] In addition to the above two main technologies, the industry has also tried some other sampling methods, such as mechanical grabbing sampling and hydraulic pushing sampling. However, these methods are either not mature enough in technology or have limited application ranges and are difficult to be widely used in deep coal seam sampling. Generally speaking, the limitations of the current fixed-point sampling technology in the coal industry are mainly reflected in the following aspects: First, the reliability and adaptability of the sampling equipment are insufficient, making it difficult to cope with the complex and changeable geological conditions of deep coal seams; second, the sampling success rate and sample representativeness are affected by various factors, and the data accuracy is difficult to fully meet the requirements of gas content measurement; third, the existing technologies have shortcomings in terms of operation convenience and cost control, and it is difficult to achieve efficient and low-cost large-scale application. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a telescopic closed sampling device and its use method.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] On the one hand, the present invention provides a telescopic sealed sampling device, which includes a drill bit, a sampling core shaft, a device housing, and an elastic short section; the sampling core shaft is slidably arranged in the device housing, one end is connected to the drill bit, and the other end is connected to the elastic short section; a sampling cavity is arranged in the middle of the sampling core shaft; three limit pins and a limit guide rail are arranged on the inner wall of the middle part of the device housing; two limit grooves for cooperating with the limit pins are arranged on the outer wall of the middle part of the sampling core shaft; a limit ring is arranged on the outer wall of the sampling core shaft near the elastic short section end, a limit foot is arranged on the limit ring, and the limit foot slides in the limit guide rail; sealing rings are arranged at both ends of the sampling core shaft.

[0009] Furthermore, the elastic short section includes an elastic short section housing and a spring. One end of the elastic short section housing is connected to the device housing, and the other end supports the spring. One end of the spring is connected to the sampling core shaft.

[0010] Furthermore, both ends of the sampling core shaft are cylinders, and the middle part is a hexagonal prism.

[0011] Furthermore, the outer wall of the device housing is cylindrical, and the inner wall cooperates with the sampling core shaft.

[0012] Furthermore, a through hole for ventilation and water passage is arranged on the axis of the sampling core shaft. An air vent and a valve are arranged in the shaft body of the sampling core shaft. One end of the air vent communicates with the sampling cavity, and the other end communicates with the elastic short section.

[0013] Furthermore, the limit guide rail is Y-shaped.

[0014] On the other hand, the present invention provides a method for using a telescopic sealed sampling device, which includes the following steps:

[0015] S1: Insert the first limit pin of the device housing into the first limit groove of the sampling core shaft, so as to limit the sampling core shaft in the device housing;

[0016] S2: Drilling construction: Connect the telescopic sealed sampling device to the drill pipe. After ventilation or water passage, use the drill rig for drilling construction. During the drilling construction process, control the feed force of the drill rig to be less than the shear breaking force of the first limit pin;

[0017] S3: Sampling mandrel extends: After drilling to the sampling location, control the feed force of the drill rig to be greater than the shear failure force of the first limit pin; at this time, the first limit pin is damaged and loses its limiting function, the sampling mandrel is restricted by the bottom of the hole and remains stationary, and the device housing moves towards the bottom of the hole under the action of the feed force of the drill rig until the near-spring end of the limit guide rail contacts the limit foot set on the limit ring, and the device housing is restricted and stops moving; control the drill rig to move the drill pipe together with the telescopic sealed sampling device outwards by a certain distance; during the process of the telescopic sealed sampling device moving outwards, the sampling mandrel extends towards the drill bit under the action of the spring until the second limit pin enters the second limit groove, and during this process, the limit foot set on the limit ring moves along the limit guide rail to the near-drill-bit end;

[0018] S4: Sampling: Stop the air supply and water supply, and use the drill rig to continue drilling deeper for a certain distance and then stop drilling. During the drilling construction process, control the feed force of the drill rig to be less than the shear failure force of the second limit pin. During this process, the coal body broken by the drill bit accumulates at the sampling cavity; control the drill rig to apply a feed force greater than the shear failure force of the second limit pin; at this time, the second limit pin is damaged and loses its limiting function, the sampling mandrel is restricted by the bottom of the hole and remains stationary, and the device housing moves towards the bottom of the hole under the action of the feed force of the drill rig, shoveling the accumulated coal sample into the sampling cavity until the near-spring end of the limit guide rail contacts the limit foot set on the limit ring, and the device housing is restricted and stops moving, and the third limit pin enters the second limit groove, limiting the sampling mandrel in the device housing. Under the combined action of the first sealing ring and the second sealing ring, the coal sample in the sampling cavity is in a sealed state;

[0019] S5: Drill withdrawal: Use the drill rig to withdraw the telescopic sealed sampling device, disassemble the elastic short joint housing, take out the spring, collect the parameters of the coal sample taken through the valve. After the collection is completed, disassemble the third limit pin and take out the sampling mandrel to obtain the coal sample.

[0020] The beneficial effects of the present invention are as follows: The present invention realizes the purpose of downhole ordinary drill rig with-drill sealed sampling by self-designed action mode for sampling and the sealed structure to ensure that the taken coal sample is in a sealed state, and has the characteristics of good sampling effect and convenient operation.

[0021] Other advantages, objectives and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. Description of the Drawings

[0022] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0023] Figure 1 It is a schematic structural diagram of a telescopic and sealed sampling device;

[0024] Figure 2 It is a schematic diagram of the installation state of the device described in step S1;

[0025] Figure 3 It is a schematic diagram of the state where the sampling mandrel extends described in step S3;

[0026] Figure 4 It is a schematic diagram of the sampling completion state described in step S4.

[0027] Reference numerals: drill bit 1, sampling mandrel 2, sealing ring 3, device housing 4, first limit groove 5, first limit pin 6, second limit pin 7, through hole 8, limit guide rail 9, vent hole 10, second limit groove 11, third limit pin 12, limit ring 13, sealing ring 14, valve 15, spring 16, elastic short section 17, elastic short section housing 18, flow-through hole 19. Specific embodiments

[0028] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0029] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as a limitation on the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0030] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation on the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0031] Example 1:

[0032] As Figure 1 shown, the present invention provides a telescopic sealed sampling device, including a drill bit 1, a sampling core shaft 3, a device housing 4, and an elastic short section 17; the sampling core shaft 2 realizes coal sample collection by its telescopic action; a sealing ring is arranged between the device housing 4 and the sampling core shaft 2 to ensure that the sampled coal sample is in a sealed state; the elastic short section 17 provides part of the power for the telescopic movement of the sampling core shaft. The sampling core shaft 2 is installed inside the device housing 4, connected to the drill bit 1 at one end and in contact with the spring 16 at the other end. Both ends of the sampling core shaft 2 are cylindrical, and the middle part is hexagonal; two sealing rings 3 are arranged on the cylindrical section near the drill bit end of the sampling core shaft 2; a sampling cavity, a first limiting groove 5, and a second limiting groove 11 are arranged on the hexagonal section in the middle of the sampling core shaft 2; two sealing rings 14 and a limiting ring 13 are arranged on the cylindrical section near the spring end of the sampling core shaft 2; a through hole 8 is arranged on the axis of the sampling core shaft 2 for ventilation and water passage; a ventilation hole 10 is arranged on the shaft body of the sampling core shaft 2, communicating with the sampling cavity at one end and the elastic short section 17 at the other end, and a valve 15 is arranged. The device housing is a tubular structure installed outside the sampling core shaft, with one end in a free state and the other end connected to the elastic short section.

[0033] The outer wall of the device housing is cylindrical, with cylindrical inner walls at both ends and a hexagonal inner wall in the middle. A first limiting pin 6, a second limiting pin 7, a third limiting pin 12, and a limiting guide rail 9 are arranged on the hexagonal inner wall section in the middle.

[0034] The limiting guide rail is Y-shaped and is used to limit the moving distance of the sampling core shaft. It includes an I end and a III end close to the spring, and a II end close to the drill bit.

[0035] The elastic short section includes an elastic short section housing 18 and a spring 16. An overflow hole 19 for ventilation and water passage is arranged at the axis center of the elastic short section housing. One end of the spring is in contact with the sampling core shaft 2, and the other end is in contact with the elastic short section housing 18. The limiting ring 13 is a ring-shaped structure, embedded in the cylindrical section near the spring end of the sampling core shaft, and can rotate along the axis of the cylinder; limiting feet are arranged on the limiting ring 13, and the limiting feet only move along the limiting guide rail 9.

[0036] Example 2:

[0037] The present invention also provides a method for using a telescopic sealed sampling device, including the following steps:

[0038] S1: Device installation: As Figure 2 shown, the sampling core shaft installed with the sealing ring, drill bit, and valve is installed into the device housing, and the first limiting pin 6 is installed at the first limiting groove 5 to realize the limitation of the sampling core shaft; the second limiting pin 7 and the third limiting pin 12 are installed; the spring and the elastic short section housing are installed.

[0039] S2: Drilling construction: Connect the telescopic airtight sampling device to the drill pipe. After ventilation or water supply, use the drill to carry out drilling construction. During the drilling construction process, control the feed force Fa of the drill to be less than the shearing force Fx of the first limit pin 6.

[0040] S3: Extension of the sampling mandrel: As Figure 3 shown, after drilling to the sampling location, control the feed force Fb of the drill to be greater than the shearing force Fx of the first limit pin 6; at this time, the first limit pin 6 is damaged and loses its limiting function. The sampling mandrel is kept stationary by the bottom-hole limit. The device housing moves towards the bottom hole under the action of the feed force of the drill until the I end of the limit guide rail 9 contacts the limit foot set on the limit ring, and the device housing is limited and stops moving. Control the drill to move the drill pipe together with the telescopic airtight sampling device out of the hole by a certain distance; during the process of the telescopic airtight sampling device moving out of the hole, the sampling mandrel extends towards the free end of the device housing under the action of the spring 16 until the second limit pin 7 enters the second limit groove 11. During this process, the limit foot set on the limit ring moves along the limit guide rail from the I end of the limit guide rail to the II end of the limit guide rail. Complete the action of extending the sampling mandrel.

[0041] S4: Sampling: As Figure 4 shown, stop the drill and continue to drill deeper for a certain distance in the state of stopping air supply and water supply, and then stop drilling. During the drilling construction process, control the feed force Fa of the drill to be less than the shearing force Fx of the second limit pin 7. During this process, the coal body broken by the drill bit accumulates behind the drill bit, that is, at the sampling cavity; control the drill to apply a feed force Fb greater than the shearing force Fx of the second limit pin 7; at this time, the second limit pin 7 is damaged and loses its limiting function. The sampling mandrel is kept stationary by the bottom-hole limit. The device housing moves towards the bottom hole under the action of the feed force of the drill, shovels the accumulated coal sample into the sampling cavity until the III end of the limit guide rail 9 contacts the limit foot set on the limit ring, and the device housing is limited and stops moving, and the third limit pin 12 enters the second limit groove 11 to limit the sampling mandrel in the device housing. At the same time, due to the combined action of the sealing ring 3 and the sealing ring 14, the coal sample in the sampling cavity is in a sealed state.

[0042] S5: Withdrawal of the drill: Use the drill to withdraw the drill and take out the telescopic airtight sampling device, disassemble the elastic short joint housing, take out the spring, collect the parameters of the coal sample taken through the valve 15. After the collection is completed, disassemble the third limit pin 12 and take out the sampling mandrel to obtain the coal sample.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A telescopic sealed sampling device, characterized in that: It includes a drill bit, a sampling mandrel, a device housing and an elastic short joint; the sampling mandrel is slidably arranged in the device housing, with one end connected to the drill bit and the other end connected to the elastic short joint; a sampling cavity is provided in the middle of the sampling mandrel; three limit pins and a limit guide rail are provided on the inner wall of the middle part of the device housing; two limit grooves for cooperating with the limit pins are provided on the outer wall of the middle part of the sampling mandrel; a limit ring is provided on the outer wall of the sampling mandrel near the elastic short joint end, and a limit foot is provided on the limit ring, and the limit foot slides in the limit guide rail; sealing rings are provided at both ends of the sampling mandrel.

2. The telescopic sealed sampling device according to claim 1, characterized in that: The elastic short joint includes an elastic short joint housing and a spring. One end of the elastic short joint housing is connected to the device housing, and the other end supports the spring. One end of the spring is connected to the sampling mandrel.

3. The telescopic sealed sampling device according to claim 1, wherein: Both ends of the sampling mandrel are cylindrical, and the middle part is hexagonal.

4. The telescopic sealed sampling device according to claim 3, wherein: The outer wall of the device housing is cylindrical, and the inner wall cooperates with the sampling mandrel.

5. The telescopic sealed sampling device according to claim 1, characterized in that: A through hole for ventilation and water flow is provided on the axis of the sampling mandrel. An air vent and a valve are provided in the shaft body of the sampling mandrel. One end of the air vent communicates with the sampling cavity, and the other end communicates with the elastic short joint.

6. The telescopic sealed sampling device according to claim 1, characterized in that: The limit guide rail is Y-shaped.

7. A method for using a telescopic airtight sampling device as described in any one of claims 1-6, characterized in that: It includes the following steps: S1: Insert the first limit pin of the device housing into the first limit groove of the sampling mandrel, so as to limit the sampling mandrel in the device housing; S2: Drilling construction: Connect the telescopic sealed sampling device to the drill pipe. After ventilation or water flow, use the drill rig for drilling construction. During the drilling construction process, control the feed force of the drill rig to be less than the shear breaking force of the first limit pin; S3: Sampling mandrel extension: After drilling to the sampling location, control the feed force of the drill rig to be greater than the shear breaking force of the first limit pin; at this time, the first limit pin is damaged and loses its limiting function. The sampling mandrel is limited by the bottom of the hole and remains stationary. The device housing moves towards the bottom of the hole under the action of the feed force of the drill rig until the near-spring end of the limit guide rail contacts the limit foot provided on the limit ring, and the device housing is limited and stops moving; control the drill rig to move the drill pipe together with the telescopic sealed sampling device out of the hole by a certain distance; during the process of moving the telescopic sealed sampling device out of the hole, the sampling mandrel is pushed by the spring and extends towards the drill bit direction until the second limit pin enters the second limit groove. During this process, the limit foot provided on the limit ring moves along the limit guide rail to the near-drill bit end; S4: Sampling: Stop the drill rig from drilling deeper for a certain distance after stopping the air supply and water supply, and control the feed force of the drill rig to be less than the shear breaking force of the second limit pin during the drilling construction process. During this process, the coal body broken by the drill bit accumulates at the sampling cavity; control the drill rig to apply a feed force greater than the shear breaking force of the second limit pin; at this time, the second limit pin is damaged and loses its limiting function. The sampling mandrel is limited by the bottom of the hole and remains stationary. The device housing moves towards the bottom of the hole under the action of the feed force of the drill rig, shovels the accumulated coal sample into the sampling cavity until the near-spring end of the limit guide rail contacts the limit foot provided on the limit ring, and the device housing is limited and stops moving, and the third limit pin enters the second limit groove to limit the sampling mandrel in the device housing. Under the combined action of the first sealing ring and the second sealing ring, the coal sample in the sampling cavity is in a sealed state; S5: Drill withdrawal: Use a drill to withdraw the telescopic airtight sampling device, disassemble the elastic short joint housing, take out the spring, collect the parameters of the coal sample taken through the valve. After the collection is completed, disassemble the third limit pin and take out the sampling mandrel to obtain the coal sample.

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