A device and method for fixed-point airtight sampling of deep holes in coal mines

Abstract

The present invention belongs to the technical field of coal mine sampling. It relates to a deep-hole fixed-point airtight sampling device and method for coal mines. Sampling is carried out using the deep-hole fixed-point airtight sampling device for coal mines. The deep-hole fixed-point airtight sampling device for coal mines includes a connection part connected to a drill pipe, a sampling part threadedly connected to the connection part, and a drill bit provided at the end of the sampling part and connected by threads. The sampling part includes a core-taking outer cylinder, a one-way valve, a telescopic locking mechanism, and a core-taking middle cylinder that are sequentially sleeved inside the core-taking outer cylinder, and a core-taking inner cylinder sleeved inside the core-taking middle cylinder; the core-taking inner cylinder is fixedly connected to the core-taking outer cylinder; the core-taking inner cylinder is connected to the drill bit through a sampling valve, a valve switch is provided on the sampling valve, and the core-taking middle cylinder is connected to the valve switch; the telescopic locking mechanism is driven by high-pressure water inside the drill pipe to push the core-taking middle cylinder to axially move inside the core-taking outer cylinder, thereby driving the valve switch to open and close the sampling valve. The present invention has good airtightness and can be reused.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mine sampling, and relates to a deep-hole fixed-point airtight sampling device and method for coal mines. Background Art

[0002] Determination of coal seam gas content is required for area prediction of coal mining faces and evaluation of drainage effects. With the popularization of directional long boreholes, the need for deep-hole sampling has become more obvious. In the prior art, for example, Chinese Patent with publication number CN107806341B discloses a deep-hole fixed-point airtight sampling device and sampling method for coal mines. It adopts a three-cylinder structure design of inner, middle, and outer cylinders. During the core drilling process, the core outer cylinder drives the core bit to drill coal samples, and the coal core enters the core inner cylinder through the core thin-wall bit and the ball valve. After reaching the core length, drilling stops, and high-pressure water is introduced. The high-pressure water acts on the cut-off valve after passing through the check valve. When the water pressure generates a thrust to cut the pin, the cut-off valve and the core middle cylinder move forward, driving the ball valve switch and the ball valve to rotate, thereby cutting off the core coal column and sealing the coal sample and gas in the core inner cylinder. After core sampling, connect the downhole desorption instrument to perform on-site desorption. However, it still has the following deficiencies:

[0003] (1) The core inner cylinder is sealed with a plugging ball before sampling, and the sealing effect of the plugging ball is poor, and gas and water in the borehole are likely to enter the sampling inner cylinder.

[0004] (2) The starting water pressure of sampling cannot be adjusted, which easily causes mis-triggering of the opening and closing of the ball valve, and coal slag and water enter the sampling device, affecting the accuracy of experimental results. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to solve the above problems and propose a deep-hole fixed-point airtight sampling device and method for coal mines.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A deep-hole fixed-point airtight sampling device for coal mines includes a connection part connected to a drill pipe, a sampling part threadedly connected to the connection part, and a drill bit threadedly connected to the end of the sampling part. The sampling part includes a core outer cylinder, a one-way valve, a telescopic locking mechanism, and a core middle cylinder sequentially sleeved inside the core outer cylinder, and a core inner cylinder sleeved inside the core middle cylinder; the core inner cylinder is fixedly connected to the core outer cylinder; the core inner cylinder is connected to the drill bit through a sampling valve, the sampling valve is provided with a valve switch, and the core middle cylinder is connected to the valve switch;

[0008] The telescopic locking mechanism is driven by high-pressure water in the drill pipe to push the core middle cylinder to move axially inside the core outer cylinder, thereby driving the valve switch to open and close the sampling valve.

[0009] Further, the telescopic locking mechanism includes a locking member, a pressure rod, a limiting ring, and a return spring; the return spring is arranged inside the core barrel and abuts against the end face of the core middle barrel to push the core middle barrel to reset;

[0010] The limiting ring is fixedly arranged inside the core barrel; the pressure rod is slidably arranged inside the limiting ring, one end of the pressure rod is in contact with the high-pressure water inside the drill pipe, and the other end is provided with saw teeth; a sliding groove is arranged on the side wall of the limiting ring, and a stop groove is arranged on the end face of the limiting ring; the sliding groove and the stop groove are alternately distributed at one end of the limiting ring; the locking member is arranged between the limiting ring and the core middle barrel; one end of the locking member is provided with a slider, and a first inclined surface is arranged on the end face of the slider; a second inclined surface is arranged at the entrance of the stop groove, and a third inclined surface is arranged at the entrance of the sliding groove;

[0011] The initial position of the slider is located in the sliding groove and is in sliding fit with the sliding groove; when the pressure rod pushes the locking member, the tooth top of the saw teeth abuts against the first inclined surface. When the slider is in the sliding groove, the pressure rod pushes the locking member to slide in the sliding groove, so that the locking member generates an axial displacement, and the locking member drives the core middle barrel to move, driving the sampling valve to open and close; when the slider slides out of the sliding groove, the first inclined surface pushes the locking member to generate a circumferential rotation, so that the first inclined surface cooperates with the second inclined surface, and the slider slides into the stop groove to lock the position of the core middle barrel, and the sampling valve remains in the open state; when the pressure rod pushes the locking member again, the locking member rotates so that the first inclined surface cooperates with the third inclined surface, the slider resets to the sliding groove, and at the same time under the action of the return spring, the core middle barrel drives the sampling valve to close.

[0012] Further, the inclination directions and angles of the first inclined surface, the second inclined surface, and the third inclined surface are the same.

[0013] Further, the number of teeth of the saw teeth is the sum of the numbers of the sliding groove and the stop groove.

[0014] Further, a water pressure regulating disc is arranged between the one-way valve and the telescopic locking mechanism; a plurality of water permeable holes are arranged on the water pressure regulating disc, and detachable screws are arranged in the water permeable holes, and the water pressure acting on the telescopic locking mechanism is changed by adjusting the number of screws.

[0015] Further, a toothed disc is arranged on the edge of the valve switch; a toothed groove is arranged at the position of the core middle barrel corresponding to the valve switch, and the toothed groove is meshed with the toothed disc.

[0016] Further, an inner barrel base is arranged at one end of the core inner barrel far away from the drill bit, and an analysis interface is arranged on the inner barrel base.

[0017] A method for taking sealed samples at fixed points in deep coal mine holes uses the above-mentioned device for taking sealed samples at fixed points in deep coal mine holes, and includes the following steps:

[0018] 1) Conduct sampling hole drilling construction. After the sampling drilling is completed, withdraw the drill pipe, connect the coal mine deep-hole fixed-point airtight sampling device to the drill pipe. At this time, the sampling valve is in the closed state, and send the coal mine deep-hole fixed-point airtight sampling device to the sampling point through the drill pipe;

[0019] 2) After the coal mine deep-hole fixed-point airtight sampling device is sent to the sampling point, increase the water pressure to the set driving water pressure. At this time, the high water pressure drives the telescopic locking mechanism to act, the core-taking middle cylinder extends forward, the sampling valve opens, and sampling is carried out after the water pressure is reduced;

[0020] 3) After sampling is completed, increase the water pressure again, drive the telescopic locking mechanism to act again, close the water injection, the core-taking middle cylinder resets, and the sampling valve closes to complete the sampling.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The telescopic locking mechanism adopted in the present invention is similar to the principle of the telescopic locking mechanism of a ballpoint pen. The high-pressure water is used to drive the telescopic locking mechanism to open and close the sampling valve. The sampling process realizes the maintenance of the open state of the sampling valve through the stop groove. Only the high-pressure water needs to be started when the sampling valve is opened and closed, and the high-pressure state does not need to be maintained during the sampling process, avoiding the high-pressure water from entering the coal sample and affecting the measurement of the coal sample.

[0023] 2. The present invention controls the starting water pressure of the telescopic locking mechanism through the water pressure regulating disc, which can effectively control the starting water pressure, avoid the disadvantages of using high-pressure water cutting in the prior art, and the device will not cause damage during use and can be reused.

[0024] Other advantages, objectives and features of the present invention will be described to some extent in the subsequent description, 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 realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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:

[0026] Figure 1 is a schematic diagram of the coal mine deep-hole fixed-point airtight sampling device in the present invention;

[0027] Figure 2 is a schematic diagram of the telescopic locking mechanism in the present invention;

[0028] Figure 3 is a schematic diagram of the pressure rod;

[0029] Figure 4It is a schematic diagram of a limit ring;

[0030] Figure 5 It is a schematic diagram of a locking member;

[0031] Figure 6 It is a schematic diagram of a water pressure regulating disc.

[0032] Reference numerals: 1 - reducing joint; 2 - core barrel; 3 - drill bit; 4 - one-way valve; 5 - water pressure regulating disc; 6 - pressure rod; 7 - limit ring; 8 - locking member; 9 - core middle barrel; 10 - core inner barrel; 11 - sampling valve; 12 - valve switch; 13 - return spring; 14 - inner barrel base; 15 - analysis interface; 61 - serration; 71 - sliding groove; 72 - stop groove; 73 - second inclined plane; 74 - third inclined plane; 81 - slider; 82 - first inclined plane. Detailed implementation manners

[0033] The following uses specific specific examples to illustrate the implementation manners 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 implementation manners. 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.

[0034] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and cannot be understood as a limitation to 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.

[0035] 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 position relationship, it is based on the orientation or position relationship shown in the drawings. It is 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 position relationship in the drawings are only for illustrative purposes and cannot be understood as a limitation to 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.

[0036] Please refer to Figures 1 to 6, it is a device for deep-hole fixed-point airtight sampling in coal mines, including a connecting part connected to a drill pipe, a sampling part threadedly connected to the connecting part, and a drill bit 3 threadedly connected to the end of the sampling part. The connecting part is a reducing joint 1. The sampling part includes a core barrel 2, a one-way valve 4, a telescopic locking mechanism, and a core barrel 9 that are sequentially sleeved inside the core barrel 2, and a core barrel 10 sleeved inside the core barrel 9; the core barrel 10 is fixedly connected to the core barrel 2; a sampling valve 11 is connected between the core barrel 10 and the drill bit 3, a valve switch 12 is arranged on the sampling valve 11, and the core barrel 9 is connected to the valve switch 12;

[0037] The telescopic locking mechanism is driven by high-pressure water inside the drill pipe to push the core barrel 9 to move axially inside the core barrel 2, thereby driving the valve switch 12 to realize the opening and closing of the sampling valve 11.

[0038] The telescopic locking mechanism includes a locking part 8, a pressure rod 6, a limit ring 7, and a return spring 13; the return spring 13 is arranged inside the core barrel 2 and abuts against the end face of the core barrel 9 to push the core barrel 9 to reset;

[0039] The limit ring 7 is fixedly arranged inside the core barrel 2; the pressure rod 6 is slidably arranged inside the limit ring 7. One end of the pressure rod 6 is in contact with the high-pressure water inside the drill pipe, and the other end is provided with a sawtooth 61; a sliding groove 71 is arranged on the side wall of the limit ring 7, and a stop groove 72 is arranged on the end face of the limit ring 7; the sliding groove 71 and the stop groove 72 are alternately distributed at one end of the limit ring 7; the locking part 8 is arranged between the limit ring 7 and the core barrel 9; one end of the locking part 8 is provided with a slider 81, and a first inclined surface 82 is arranged on the end face of the slider 81; a second inclined surface 73 is arranged at the entrance of the stop groove 72, and a third inclined surface 74 is arranged at the entrance of the sliding groove 71; the inclination directions and angles of the first inclined surface 82, the second inclined surface 73, and the third inclined surface 74 are the same. The number of teeth of the sawtooth 61 is the sum of the numbers of the sliding groove 71 and the stop groove 72, and each sliding groove 71 and stop groove 72 corresponds to a sawtooth 61.

[0040] The initial position of the slider 81 is located within the sliding groove 71 and is in sliding fit with the sliding groove 71; when the pressing rod 6 pushes the locking member 8, the tooth crest of the sawtooth 61 abuts against the first inclined surface 82. When the slider 81 is within the sliding groove 71, the pressing rod 6 pushes the locking member 8 to slide within the sliding groove 71, thereby causing the locking member 8 to have an axial displacement. The locking member 8 drives the coring middle cylinder 9 to move, driving the sampling valve 11 to open and close; when the slider 81 slides out of the sliding groove 71, the first inclined surface 82 pushes the locking member 8 to rotate circumferentially, causing the first inclined surface 82 to cooperate with the second inclined surface 73, and the slider 81 slides into the stop groove 72 to lock the position of the coring middle cylinder 9, and the sampling valve 11 remains in the open state; when the pressing rod 6 pushes the locking member 8 again, the locking member 8 rotates to make the first inclined surface 82 cooperate with the third inclined surface 74, and the slider 81 resets to the sliding groove 71. At the same time, under the action of the return spring 13, the coring middle cylinder 9 drives the sampling valve 11 to close.

[0041] A water pressure regulating disc 5 is provided between the one-way valve 4 and the telescopic locking mechanism; the water pressure regulating disc 5 is provided with a plurality of water permeable holes, and detachable screws are provided in the water permeable holes. The water pressure acting on the telescopic locking mechanism is changed by adjusting the number of screws.

[0042] A toothed disc is provided at the edge of the valve switch 12; a toothed groove corresponding to the valve switch 12 is provided on the coring middle cylinder 9, and the toothed groove meshes with the toothed disc.

[0043] An inner cylinder base 14 is provided at one end of the coring inner cylinder 10 away from the drill bit 3, and an analysis interface 15 is provided on the inner cylinder base 14. After sampling, gas analysis measurement is directly carried out through the analysis interface 15.

[0044] A method for coal mine deep hole fixed-point sealed sampling uses the coal mine deep hole fixed-point sealed sampling device in this embodiment for sampling, including the following steps:

[0045] 1) Carry out sampling hole drilling construction. After the sampling borehole construction is completed, withdraw the drill pipe, connect the coal mine deep hole fixed-point sealed sampling device to the drill pipe. At this time, the sampling valve 11 is in the closed state, and the coal mine deep hole fixed-point sealed sampling device is sent to the sampling point through the drill pipe;

[0046] 2) When the coal mine deep hole fixed-point sealed sampling device is sent to the sampling point, increase the water pressure to the set driving water pressure. At this time, the high water pressure drives the telescopic locking mechanism to act, the coring middle cylinder 9 extends forward, the sampling valve 11 opens, the slider 81 slides into the stop groove 72, and the sampling valve 11 remains in the open state. After reducing the water pressure, sampling is carried out;

[0047] 3) After sampling, increase the water pressure again to drive the telescopic locking mechanism to act again. The slider 81 slides from the stop groove 72 into the sliding groove 71, stop water injection, the coring middle cylinder 9 resets under the action of the return spring 13, the sampling valve 11 closes, and sampling is completed.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. 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 within the scope of the claims of the present invention.

Claims

1. A deep-hole fixed-point airtight sampling device for coal mines, comprising a connecting part connected to a drill pipe, a sampling part threadedly connected to the connecting part, and a drill bit arranged at the end of the sampling part and connected by threads, characterized in that: The sampling part includes a coring outer cylinder, a one-way valve, a telescopic locking mechanism, and a coring middle cylinder that are sequentially sleeved inside the coring outer cylinder, and a coring inner cylinder that is sleeved inside the coring middle cylinder; the coring inner cylinder is fixedly connected to the coring outer cylinder; the coring inner cylinder is connected to the drill bit through a sampling valve, a valve switch is provided on the sampling valve, and the coring middle cylinder is connected to the valve switch; The telescopic locking mechanism is driven by high-pressure water inside the drill pipe to push the coring middle cylinder to axially move inside the coring outer cylinder, thereby driving the valve switch to realize the opening and closing of the sampling valve; The telescopic locking mechanism includes a locking member, a pressure rod, a limiting ring, and a return spring; the return spring is arranged inside the coring outer cylinder and abuts against the end face of the coring middle cylinder to push the coring middle cylinder to reset; The limiting ring is fixedly arranged inside the coring outer cylinder; the pressure rod slides inside the limiting ring, one end of the pressure rod contacts the high-pressure water inside the drill pipe, and the other end is provided with sawteeth; a sliding groove is provided on the side wall of the limiting ring, and a stop groove is provided on the end face of the limiting ring; the sliding groove and the stop groove are alternately distributed at one end of the limiting ring; the locking member is arranged between the limiting ring and the coring middle cylinder; one end of the locking member is provided with a slider, and a first inclined surface is provided on the end face of the slider; a second inclined surface is provided at the entrance of the stop groove, and a third inclined surface is provided at the entrance of the sliding groove; The initial position of the slider is located inside the sliding groove and is in sliding fit with the sliding groove; when the pressure rod pushes the locking member, the tooth top of the sawteeth abuts against the first inclined surface. When the slider is inside the sliding groove, the pressure rod pushes the locking member to slide inside the sliding groove, so that the locking member generates an axial displacement, and the locking member drives the coring middle cylinder to move to drive the sampling valve to open and close; when the slider slides out of the sliding groove, the first inclined surface pushes the locking member to generate a circumferential rotation, so that the first inclined surface cooperates with the second inclined surface to make the slider slide into the stop groove to realize the position locking of the coring middle cylinder, and the sampling valve remains in the open state; when the pressure rod pushes the locking member again, the locking member rotates to make the first inclined surface cooperate with the third inclined surface, and the slider resets to the sliding groove. At the same time, under the action of the return spring, the coring middle cylinder drives the sampling valve to close; The inclination directions and angles of the first inclined surface, the second inclined surface, and the third inclined surface are the same; a water pressure adjusting disc is arranged between the one-way valve and the telescopic locking mechanism; a plurality of water permeable holes are provided on the water pressure adjusting disc, and removable screws are provided in the water permeable holes, and the water pressure acting on the telescopic locking mechanism is changed by adjusting the number of screws.

2. The deep-hole fixed-point airtight sampling device for coal mines according to claim 1, wherein: The number of teeth of the sawteeth is the sum of the numbers of the sliding groove and the stop groove.

3. The deep-hole fixed-point airtight sampling device for coal mines according to claim 1, characterized in that: A toothed disc is arranged at the edge of the valve switch; a toothed groove is provided at the position of the coring middle cylinder corresponding to the valve switch, and the toothed groove meshes with the toothed disc.

4. The deep-hole fixed-point airtight sampling device for coal mines according to claim 1, characterized in that: An inner cylinder base is provided at one end of the coring inner cylinder away from the drill bit, and an analysis interface is provided on the inner cylinder base.

5. A method for deep-hole fixed-point airtight sampling in coal mines, characterized in that: Sampling is carried out by using the coal mine deep-hole fixed-point closed sampling device according to any one of claims 1 to 4, including the following steps: 1) Conduct sampling hole drilling construction. After the sampling drilling is completed, withdraw the drill pipe, connect the coal mine deep hole fixed-point airtight sampling device to the drill pipe. At this time, the sampling valve is in the closed state, and send the coal mine deep hole fixed-point airtight sampling device to the sampling point through the drill pipe; 2) After the coal mine deep hole fixed-point airtight sampling device is sent to the sampling point, increase the water pressure to the set driving water pressure. At this time, the high water pressure drives the telescopic locking mechanism to act, the core barrel extends forward, the sampling valve opens, and sampling is carried out after the water pressure is reduced; 3) After sampling is completed, increase the water pressure again, drive the telescopic locking mechanism to act again, close the water injection, the core barrel resets, the sampling valve closes, and sampling is completed.

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