Petal core barrel seal and method of using same

Abstract

The present application relates to a petal type core tube sealing structure of a pressure maintaining corer and a use method thereof, comprising an outer tube, a pressure maintaining controller, a core tube and a closing control tube, the pressure maintaining controller and the closing control tube are both installed in the outer tube, a petal valve for closing a lower end tube port of the core tube is installed at a lower end of the core tube, the petal valve comprises two closing blades, and a spring is arranged between the closing blades and the core tube; an inner diameter of the closing control tube is greater than an outer diameter of the core tube, an axial column which is adapted to one of the closing blades is arranged in the closing control tube, and the opened closing blade is operatively inserted between the axial column and an inner wall of the closing control tube. The petal valve directly seals the lower end of the core tube, reduces coal dust falling in the core tube from the root, almost ensures zero coal dust falling of a valve seat sealing surface, improves the sealing stability of the pressure maintaining controller and ensures the pressure maintaining performance of the corer.

Description

Technical Field

[0001] This invention relates to the field of pressure-holding core sampling equipment, and in particular to the petal-shaped core tube sealing structure of pressure-holding core sampling equipment and its usage method. Background Technology

[0002] Coal seam gas content is an important basic parameter in fields such as mine gas disaster prevention and control, evaluation of coal seam gas pre-drainage effect, evaluation and development of coalbed methane resources, so it is necessary to sample the coal seam.

[0003] The pressure-maintaining gas core drill is a gas and coal sample collection device with pressure-maintaining function. Its main working principle involves loading the pressure-maintaining gas core into an external drilling tool and continuing to drill a certain distance into the working face, allowing the coal sample to enter the core tube. The core tube is then raised to the core chamber, where a pressure-maintaining controller seals the lower end, thus providing pressure-maintaining space for the coal sample.

[0004] The pressure holding controller includes a valve seat and a valve cover. The top of the valve seat has a sealing surface that matches the valve cover. Since there is a coal sample inside the core tube, coal dust may fall onto the sealing surface of the valve seat when the core tube passes through the valve seat, which will affect the sealing performance of the valve seat and the valve cover, and ultimately affect the pressure holding performance of the core sampler. Summary of the Invention

[0005] This application provides a petal-shaped core tube sealing structure for a pressure-holding core sampler and its usage method in order to solve the above-mentioned technical problems.

[0006] This application is achieved through the following technical solution:

[0007] The petal-shaped core tube sealing structure of the pressure-holding coring device provided in this application includes an outer tube, a pressure-holding controller, a core tube, and a closing control tube. Both the pressure-holding controller and the closing control tube are installed inside the outer tube. A petal valve for closing the lower end of the core tube is installed at the lower end of the core tube. The petal valve includes two closing blades, which are symmetrically installed at the lower end of the core tube by means of pins. A spring is provided between the closing blade and the core tube, and the closing blade tends to close under the action of the spring. The closing control tube is located below the pressure-holding controller. The inner diameter of the closing control tube is larger than the outer diameter of the core tube. An axial column is provided inside the closing control tube, which is adapted to one of the closing blades. The lower end of the axial column is fixed to the closing control tube, and the upper end of the axial column is a free end. There is a gap between the upper end of the axial column and the upper end of the closing control tube. The opened closing blade is operably inserted between the axial column and the inner wall of the closing control tube.

[0008] Optionally, the spring is a torsion spring, which is sleeved on the pin.

[0009] In particular, each closed blade is equipped with two axial posts, which are used to restrain the closed blade from both sides.

[0010] Optionally, a semicircular tube segment can be cut from a conical or spherical surface to obtain a spatial curved surface, and then the spatial curved surface can be symmetrically divided into two halves to obtain two closed blades. The outer diameter of the semicircular tube segment matches the outer diameter of the core tube. After the spatial curved surface is placed inside the core tube, the outer edge of the spatial curved surface is in sealed contact with the inner wall of the core tube.

[0011] Optionally, the inner wall of the upper end of the closure control tube has a second annular protrusion, the inner diameter of which is consistent with the outer diameter of the core tube.

[0012] Specifically, the lower end of the closure control tube has a coaxial circular ring structure, the outer diameter of which is the same as the inner diameter of the core tube; the lower end of the core tube is operably fitted over the circular ring structure; the axial column is located between the circular ring structure and the inner wall of the closure control tube.

[0013] Optionally, the outer tube includes a first outer tube and a second outer tube, with the upper end of the first outer tube threadedly connected to the lower end of the second outer tube, the pressure holding controller installed inside the second outer tube, and the closing control tube installed inside the first outer tube.

[0014] The pressure holding controller includes a valve seat and a valve cover, with a sealing surface on the top of the valve seat that matches the valve cover; the valve seat and valve cover may or may not have permanent magnets.

[0015] Optionally, the upper inner wall of the first outer tube has a first annular protrusion, and the lower end of the valve seat abuts against the first annular protrusion.

[0016] The method of using the petal-shaped core tube sealing structure of the pressure-holding coring device provided in this application includes the following steps:

[0017] In the initial state: the core tube passes through the valve seat and the inner hole of the closing control tube, the valve cover is open and located in the annulus between the core tube and the outer tube; the axial column in the closing control tube supports two closing blades, the closing blades are restricted between the axial column and the inner wall of the closing control tube, and the closing blades are in the open state against the elastic force of the spring under the action of the axial column.

[0018] In operation: The core sampler completes core collection, the core tube moves upward under the action of external force, and the axial column of the closure control tube continues to support the closure blades to open them;

[0019] As the core tube continues to move upward, the axial column of the closure control tube can no longer support the closure blades. The closure blades close under the elastic force of the spring, sealing the lower end of the core tube.

[0020] The core tube continues to move upwards, and the valve cover closes.

[0021] Compared with the prior art, this application has the following beneficial effects:

[0022] 1. The petal valve of this application directly seals the lower end of the core tube, reducing the falling of coal dust inside the core tube from the source. It can almost guarantee zero falling of coal dust on the valve seat sealing surface, which can improve the sealing stability of the pressure holding controller and ensure the pressure holding performance of the core sampler.

[0023] 2. The closure control tube of this application realizes the opening and closing of the closure blade through a simple structure, and also takes into account the airtight connection with the core tube, ensuring that coal cuttings will not enter other spaces during normal drilling, reducing the blockage and other problems caused by it, and improving stability.

[0024] 3. The sealing structure adopts a petal-shaped design and uses spring force and the axial movement drive of the core tube itself. The closing control tube can be used in narrow spaces without major improvements to the existing core extractor, making it convenient to use. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the embodiments of this application and form part of this application, do not constitute a limitation on the embodiments of the present invention.

[0026] Figure 1 This is a cross-sectional view of the petal-shaped core tube sealing structure in the initial state of the embodiment;

[0027] Figure 2 yes Figure 1 Enlarged view of the cross-sectional view at point AA;

[0028] Figure 3 This is a cross-sectional view of the petal-shaped core tube sealing structure during the closing process of the closed blade in the embodiment;

[0029] Figure 4 This is a cross-sectional view of the petal-shaped core tube sealing structure after the closed blades are closed in the embodiment;

[0030] Figure 5 This is a cross-sectional view of the petal-shaped core tube sealing structure in the final state of the embodiment;

[0031] Figure 6 This is a three-dimensional diagram of the core tube during the closing process of the closing blade in the embodiment;

[0032] Figure 7 This is a three-dimensional diagram of the two closed blades in the embodiment when they are closed;

[0033] Figure 8 This is a cross-sectional view of the first outer tube in the embodiment;

[0034] Figure 9 This is a three-dimensional diagram of the closure control tube in the embodiment;

[0035] Figure 10 This is a cross-sectional view of the closure control tube in the embodiment. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in 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, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. It should also be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] like Figures 1-5 As shown, the petal-shaped core tube sealing structure of the pressure-holding coring device disclosed in this embodiment includes an outer tube, a pressure-holding controller, a core tube 5, and a closure control tube 6. The pressure-holding controller and the closure control tube 6 are coaxially mounted inside the outer tube, and the core tube 5 can pass through the center of the closure control tube 6.

[0043] The pressure holding controller includes a valve seat 3 and a valve cover 4. The top of the valve seat 3 has a sealing surface that matches the valve cover 4. The top of the valve seat 3 is movably connected to the valve cover 4 via a shaft 32. When the core tube 5 is located in the valve seat 3, the valve cover 4 is open and located in the annular space between the core tube 5 and the outer tube. When the core tube 5 is lifted to a certain height, the valve cover 4 flips over to close with the valve seat 3. This is conventional technology in the field and will not be described in detail here.

[0044] In one possible design, the valve seat 3 is provided with multiple permanent magnets 31 along the circumference, and the valve cover 4 is also provided with permanent magnets 31. The permanent magnets 31 on the valve seat 3 can attract the permanent magnets 31 on the valve cover 4, thereby increasing the sealing pressure and improving the sealing stability.

[0045] like Figure 1 As shown in the figure, a petal valve for closing the lower end of the core tube 5 is installed at the lower end of the core tube 5. The petal valve includes two closing blades 7, which are symmetrically installed at the lower end of the core tube 5 via pins 8. A spring is provided between the closing blades 7 and the core tube 5. Under the action of the spring, the closing blades 7 tend to close.

[0046] Optionally, the spring is a torsion spring, which is fitted onto the pin 8 and can provide torque to close the closing blade 7.

[0047] Optionally, the lower end of the core tube 5 has two symmetrical notches for installing the closing blade 7 and the pin 8. It is worth noting that the side wall of the core tube 5 has a medium through-hole (not shown in the figure) for communicating with the pressure-holding cavity.

[0048] In one possible design, such as Figure 7As shown, a semi-circular tube segment is cut with a conical or spherical surface to obtain a spatial curved surface. Then, the spatial curved surface is symmetrically divided into two halves to obtain two closed blades 7. The outer diameter of the semi-circular tube segment matches the outer diameter of the core tube 5. After the spatial curved surface is placed inside the core tube 5, the outer edge of the spatial curved surface is in sealed contact with the inner wall of the core tube 5.

[0049] like Figure 9 , Figure 10 As shown, the closing control tube 6 is an annular hollow structure. The closing control tube 6 is coaxially fixed inside the outer tube. The inner diameter of the closing control tube 6 is larger than the outer diameter of the core tube 5, so that when the core tube 5 passes through the closing control tube 6, there is a gap between the inner wall of the closing control tube 6 and the outer wall of the core tube 5, which is mainly used to provide space for the movement of the closing blade 7.

[0050] The closure control tube 6 is provided with axial columns 63 that are adapted to one of the closure blades 7. The axial columns 63 are arranged circumferentially around the axis of the closure control tube 6. The circumferential diameter of the axial columns 63 is smaller than the inner diameter of the closure control tube 6 and larger than the outer diameter of the core tube 5. The axial columns 63 are used to provide support force for the opening of the closure blades 6.

[0051] The lower end of the axial column 63 is fixed to the closing control tube 6, and the upper end of the axial column 63 is a free end. There is a gap between the upper end of the axial column 63 and the upper end of the closing control tube 6 so that the closing blade 7 can be inserted between the inner wall of the axial column 63 and the closing control tube 6, thereby preventing the closing blade 7 from closing.

[0052] In one possible design, each closed blade 7 is equipped with a set of axial columns 63. The two sets of axial columns 63 are symmetrical, with two axial columns 63 in each set. The two axial columns 63 restrict the edges of the closed blade 7 from both sides, thereby overcoming the closing torque provided by the spring and preventing the closed blade 7 from closing, so that the core can enter the core tube 5.

[0053] In one possible design, the lower end of the closed control tube 6 has a coaxial circular annular structure 61 for connecting to the core tube 5, preventing the core from falling into the non-storage space during sampling. The outer diameter of the circular annular structure 61 is the same as the inner diameter of the core tube 5. Four axial columns 63 are arranged circumferentially around the axis of the circular annular structure 61.

[0054] In one possible design, there is a second annular protrusion 62 on the inner wall of the upper end of the closed control tube 6. The inner diameter of the second annular protrusion 62 is consistent with the outer diameter of the core tube 5, which can play a certain role in removing chips from the outer wall of the core tube 5 and remove some of the coal chips attached to the outer wall of the core tube 5.

[0055] In one possible design, the outer tube includes a first outer tube 1 and a second outer tube 2. The upper end of the first outer tube 1 is threaded to the lower end of the second outer tube 2. The second outer tube 2 is used to install a pressure holding controller. The diameter of the outer surface of the closing control tube 6 is the same as the inner diameter of the first outer tube 1. The closing control tube 6 is fixedly fitted with the first outer tube 1.

[0056] Optional, such as Figure 8 As shown, the upper inner wall of the first outer tube 1 has a first annular boss 11, which is used to determine the axial position of the lower end of the valve seat 3. The valve seat 3 is installed in the second outer tube 2, and its lower end abuts against the first annular boss 11.

[0057] The working principle of this embodiment:

[0058] In the initial state: such as Figure 1 , Figure 2 As shown, the core tube 5 passes through the valve seat 3 and the inner hole of the closing control tube 6. The valve cover 4 is open and located in the annular space between the core tube 5 and the second outer tube 2. The lower end of the core tube 5 is sleeved on the outer side of the circular ring structure 61. The axial column 63 inside the closing control tube 6 supports two closing blades 7. The closing blades 7 are restricted between the axial column 63 and the inner wall of the closing control tube 6. Under the action of the axial column 63, the closing blades 7 overcome the elastic force of the spring and are in the open state.

[0059] In working condition: such as Figure 3 As shown, the core sampler completes coal sample collection. The core tube 5 moves upward under the action of external force. The four axial columns 63 of the closure control tube 6 continue to support the closure blade 7 to keep it open. Excess coal dust will fall into the annular space of the closure control tube 6 to prevent the closure blade 7 from failing to close properly.

[0060] Then, the core tube 5 continues to move upward. At this point, the four axial columns 63 of the closing control tube 6 can no longer support the closing blade 7. The closing blade 7 closes under the elastic force of the spring, sealing the lower end of the core tube 5. Figure 4 As shown;

[0061] As the core tube 5 continues to move upward, the valve cover 4 closes, forming a sealed pressure-holding space, such as... Figure 5 As shown. This embodiment does not show the complete pressure-holding space, but it has pressure-holding capability under actual conditions. This is a conventional technique in the field and will not be described in detail here.

[0062] Reinstall core tube 5, remove debris from inside the closure control tube 6, clean it thoroughly, and reinstall it in its initial position.

[0063] This application utilizes a mechanical petal structure, combined with the axial movement inherent in the core tube, to achieve the opening, holding, and closing actions of the petal valve. The petal valve directly seals the lower end of the core tube, reducing coal dust falling from the core tube at the source. It can almost guarantee zero coal dust falling from the valve seat sealing surface, thereby improving the sealing stability of the pressure holding controller and ensuring the pressure holding performance of the core extractor.

[0064] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A petal core barrel seal structure of a pressure-maintaining core barrel, comprising an outer tube, a pressure-maintaining controller and a core barrel (5), the pressure-maintaining controller being installed in the outer tube, characterized in that: The core tube (5) is provided with a petal valve at the lower end thereof for closing the lower end opening of the core tube (5), the petal valve comprises two closing blades (7) which are symmetrically arranged at the lower end opening of the core tube (5) through pins (8) respectively, and a spring is arranged between the closing blades (7) and the core tube (5) so that the closing blades (7) have a closing tendency under the action of the spring; The closing control tube (6) is coaxially arranged in the outer tube below the pressure maintaining controller, the inner diameter of the closing control tube (6) is larger than the outer diameter of the core tube (5), and the closing control tube (6) is provided with an axial column (63) which is adapted to one of the closing blades (7) and is fixed at the lower end of the closing control tube (6) and has a free end at the upper end thereof, and the upper end of the axial column (63) is spaced from the end of the closing control tube (6), and the opened closing blade (7) can be operatively inserted between the axial column (63) and the inner wall of the closing control tube (6); Each closing blade (7) is provided with two axial columns (63) for limiting the closing blade (7) from both sides; The spatial curved surface is obtained by cutting a semicircular tube piece with a conical surface or a spherical surface, and then the spatial curved surface is symmetrically divided into two halves to obtain the two closing blades (7), the outer diameter of the semicircular tube piece is matched with the outer diameter of the core tube (5), and after the spatial curved surface is arranged in the core tube (5), the outer edge of the spatial curved surface is in sealing contact with the inner wall of the core tube (5); The outer tube comprises a first outer tube (1) and a second outer tube (2), the upper end of the first outer tube (1) is threadedly connected with the lower end of the second outer tube (2), the pressure maintaining controller is arranged in the second outer tube (2), and the closing control tube (6) is arranged in the first outer tube (1); The inner wall of the upper end of the first outer tube (1) is provided with a first annular boss (11), and the lower end of the valve seat (3) abuts against the first annular boss (11); The pressure maintaining controller comprises a valve seat (3) and a valve cover (4), and the top of the valve seat (3) is provided with a sealing surface matched with the valve cover (4).

2. The petal core barrel obturator of claim 1, wherein: The spring is a torsion spring which is sleeved on the pin (8).

3. The petal core barrel obturator of claim 1, wherein: The inner wall of the upper end of the closing control tube (6) is provided with a second annular boss (62), and the inner diameter of the second annular boss (62) is consistent with the outer diameter of the core tube (5).

4. The petal core barrel obturator of any of claims 1-3, wherein: The lower end of the closing control tube (6) is provided with a coaxial circular ring structure (61), the outer diameter of the circular ring structure (61) is consistent with the inner diameter of the core tube (5), and the lower end of the core tube (5) is operatively sleeved outside the circular ring structure (61); The axial column (63) is located between the circular ring structure (61) and the inner wall of the closing control tube (6).

5. The petal core barrel closure of any of claims 1-3, wherein: Permanent magnets (31) are arranged on the valve seat (3) and the valve cover (4).

6. The method of using the petal core barrel packer of any one of claims 1-5, wherein: The method comprises the following steps: Initial state: the core tube (5) passes through the valve seat (3) and the inner hole of the closing control tube (6), the valve cover (4) is opened and located in the annular space between the core tube (5) and the outer tube; the axial column (63) in the closing control tube (6) corresponds to support the two closing vanes (7), the closing vanes (7) are limited between the axial column (63) and the inner wall of the closing control tube (6), and the closing vanes (7) are in an open state under the action of the axial column (63) and overcome the elastic force of the spring; Working state: the corer completes core collection, the core tube (5) moves upward under the action of external force, the axial column (63) of the closing control tube (6) continues to support the closing vanes (7) to make them open; The core tube (5) continues to move upward, the axial column (63) of the closing control tube (6) can no longer support the closing vanes (7), the closing vanes (7) are closed under the action of the elastic force of the spring, and the lower end of the core tube (5) is sealed; The core tube (5) continues to move upward, and the valve cover (4) is closed.

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