Double-spring reset structure for subsurface safety valve

Abstract

The utility model relates to the technical field of reset structures, and provides a double-spring reset structure for a subsurface safety valve, which is used for storing force when the valve is opened and promoting a central pipe to reset when the valve is closed, and comprises an upper spring and a lower spring, and the upper spring and the lower spring are mounted in an abutting manner and are opposite in rotating direction. According to the utility model, one existing spring is designed into the upper spring and the lower spring which are arranged in a butting manner and are opposite in rotating direction, so that the torsion generated by the upper spring and the lower spring can be mutually counteracted, and the damage to the piston assembly is reduced.

Description

Technical Field

[0001] This utility model relates to the field of reset structure technology, and more specifically, to a double-spring reset structure for a downhole safety valve. Background Technology

[0002] A downhole safety valve is a downhole tool installed inside the wellbore and connected to the tubing to prevent blowouts and ensure production safety. Its working principle is as follows: When the well is in normal production, the surface pressure control system transmits pressure to the piston assembly through the hydraulic control line. The piston rod pushes the central tube and compresses the return spring. As the pressure in the hydraulic control line increases, the central tube gradually pushes open the valve plate, opening the downhole safety valve and thus connecting the production channel. When the downhole fluid pressure becomes abnormal, the surface pressure control system cuts off the pressure in the hydraulic control line. The central tube returns to its original position under the action of the return spring, and the valve plate returns to its original position under the action of the return torsion spring, closing the downhole safety valve and thus disconnecting the production channel.

[0003] It is evident that the return spring, as the reset structure of the central tube, plays an important role in downhole safety valves. Since the return spring is a helical structure, it generates torque when compressed. For large-volume downhole safety valves, the torque generated when the return spring is compressed is relatively large, which can easily cause damage (deformation, bending) to the piston assembly. Utility Model Content

[0004] The purpose of this invention is to provide a double-spring reset structure for downhole safety valves, thereby overcoming the aforementioned deficiencies in the prior art.

[0005] This utility model is achieved through the following technical solution:

[0006] A double-spring reset structure for a downhole safety valve is used to store force when the valve is opened and to reset the central tube when the valve is closed. The structure includes an upper spring and a lower spring, which are mounted opposite each other and rotate in opposite directions.

[0007] Optionally, the diameter of the upper spring is equal to the diameter of the lower spring, and the length of the upper spring is also equal to the length of the lower spring.

[0008] Optionally, the top surfaces of the upper spring and the lower spring are planar.

[0009] Optionally, an annular washer is provided between the upper spring and the lower spring.

[0010] Optionally, the inner edges of both sides of the annular gasket are provided with positioning grooves, the diameter of which is equal to the outer diameter of the upper spring and the lower spring.

[0011] Optionally, the lower end of the lower spring is supported by a planar bearing.

[0012] Optionally, the planar bearing includes a bearing body and a bearing housing, the bearing housing is fixedly disposed, the bearing housing is provided with a support ring groove, and the bearing body is installed in the support ring groove.

[0013] Optionally, the bearing housing is fixed in position by a resilient retaining ring.

[0014] The technical solution of this utility model has at least the following advantages and beneficial effects:

[0015] 1. In this utility model, an existing spring is designed as an upper spring and a lower spring that are mounted opposite each other and rotate in opposite directions. In this way, the torque generated by the upper spring and the lower spring can cancel each other out, reducing damage to the piston assembly.

[0016] 2. In this utility model, the diameter and length of the upper and lower springs are equal, which can make the torque values ​​generated by the two equal, improve the mutual cancellation effect, and avoid damage to the piston assembly as much as possible.

[0017] 3. In this utility model, a planar bearing is provided at the lower end of the lower spring. When the resetting structure tends to twist when compressed, the planar bearing can cause the lower end of the resetting structure to twist in the opposite direction, thereby minimizing the torque generated when the resetting structure is compressed. Attached Figure Description

[0018] Figure 1 A diagram illustrating the usage state of a double-spring reset structure for a downhole safety valve provided by this utility model;

[0019] Figure 2 for Figure 1 Enlarged view of point A in the image;

[0020] Figure 3 for Figure 2 Enlarged view of point B in the image;

[0021] Figure 4 for Figure 2 Enlarged view of point C in the image;

[0022] Reference numerals: 1-Upper spring, 2-Lower spring, 3-Annular washer, 4-Bearing body, 5-Bearing seat, 6-Elastic retaining ring, 7-Center tube, 8-Spring cylinder, 9-Piston assembly. Detailed Implementation

[0023] refer to Figure 1A double-spring reset structure for a downhole safety valve is disclosed, used to store force when the valve is opened and to reset the central tube 7 when the valve is closed. It should be understood that this invention only improves the reset structure and its installation structure in the downhole safety valve; other structures of the downhole safety valve and the installation position of the reset structure are achievable by those skilled in the art based on existing technology and common knowledge in the field. As one existing structure, the reset structure is installed in the cavity formed between the central tube 7 and the spring cylinder 8, with one end abutting against the lower end of the piston assembly 9 and the other end abutting against the support step inside the spring cylinder 8.

[0024] refer to Figure 2 This invention improves upon the above-mentioned features. Specifically, the reset structure includes an upper spring 1 and a lower spring 2, which are mounted opposite each other and rotate in opposite directions. This ensures that the torque generated by the upper spring 1 and the lower spring 2 cancels each other out, reducing damage to the piston assembly 9. Furthermore, the diameters of the upper spring 1 and the lower spring 2 are equal, and their lengths are also equal, ensuring that the torque generated during compression is equal, further enhancing the canceling effect and minimizing damage to the piston assembly 9.

[0025] refer to Figure 3 In this embodiment, the top surfaces of the upper spring 1 and the lower spring 2 are flat, which better ensures axial compression. Furthermore, an annular washer 3 can be provided between the upper spring 1 and the lower spring 2 to better ensure that the upper spring 1 and the lower spring 2 are flat against each other.

[0026] It should be understood that the inner diameter of the annular gasket 3 is larger than the outer diameter of the central tube 7, and the outer diameter of the annular gasket 3 is smaller than the inner diameter of the spring cylinder 8, ensuring that the annular gasket 3 can move smoothly when the upper spring 1 and the lower spring 2 are compressed or restored, avoiding jamming. Furthermore, positioning grooves can be provided on the inner edges of both sides of the annular gasket 3, with the diameter of the positioning grooves equal to the outer diameters of the upper spring 1 and the lower spring 2. The ends of the upper spring 1 and the lower spring 2 are installed in the positioning grooves to restrict the radial position of the annular gasket 3.

[0027] refer to Figure 4 In this embodiment, the lower end of the lower spring 2 is supported by a planar bearing. When the reset structure tends to twist when compressed, the planar bearing can cause the lower end of the reset structure to twist in the opposite direction, thereby avoiding torque as much as possible when the reset structure is compressed.

[0028] The planar bearing includes a bearing body 4 and a bearing housing 5. The bearing housing 5 has a support ring groove, and the bearing body 4 is installed in the support ring groove. The bearing housing 5 is fixedly installed. Alternatively, the position of the bearing housing 5 is fixed by an elastic retaining ring 6. The elastic retaining ring 6 is a commonly used mechanical standard part, also known as a retaining ring, snap ring, etc., and is often used to limit the axial movement of parts. Those skilled in the art should know its structure and installation method, which will not be described in detail here. In addition, in order to limit the radial position of the bearing housing 5, a positioning cone surface is designed on the support step of the spring cylinder 8 in this embodiment, and the end of the bearing housing 5 away from the lower spring 2 is designed as a cone surface structure that mates with the positioning cone surface. In other embodiments, the outer diameter of the bearing housing 5 can also be designed to be equal to the inner diameter of the spring cylinder 8.

[0029] In other embodiments, the position of the bearing housing 5 can of course be fixed in other ways, for example, in some embodiments it can be connected to the spring sleeve 8 by a screw arranged radially.

[0030] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A double-spring reset structure for a downhole safety valve, used to store force when the valve is opened and to reset the central tube when the valve is closed, characterized in that, It includes an upper spring and a lower spring, which are mounted opposite each other and rotate in opposite directions; the diameters of the upper spring and the lower spring are equal, and the lengths of the upper spring and the lower spring are also equal; the opposing surfaces of the upper spring and the lower spring are flat.

2. The double-spring reset structure for downhole safety valves according to claim 1, characterized in that, An annular washer is provided between the upper spring and the lower spring.

3. The double-spring reset structure for downhole safety valves according to claim 2, characterized in that, The inner edges of both sides of the annular gasket are provided with positioning grooves, the diameter of which is equal to the outer diameter of the upper spring and the lower spring.

4. The double-spring reset structure for a downhole safety valve according to any one of claims 1-3, characterized in that, The lower end of the lower spring is supported by a planar bearing.

5. The double-spring reset structure for a downhole safety valve according to claim 4, characterized in that, The planar bearing includes a bearing body and a bearing housing. The bearing housing is fixedly installed and has a support ring groove. The bearing body is installed in the support ring groove.

6. The double-spring reset structure for a downhole safety valve according to claim 5, characterized in that, The bearing housing is fixed in position by a flexible retaining ring.

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