210MPa surface safety valve

Abstract

The invention relates to the technical field of petroleum and natural gas wellhead equipment, in particular to a 210MPa surface safety valve which comprises a cut-off assembly, a valve rod assembly, a valve rod assembly and a control assembly. The driving assembly comprises a pressure cylinder, a piston cylinder arranged outside the pressure cylinder in a sleeving mode, a piston arranged in the piston cylinder and a valve rod connected and matched with the piston, the piston and the piston cylinder are arranged to axially move relative to the valve body, the size constraint of the piston is released, the stress area of the piston is increased, and the safety valve can be opened and closed under the same opening force. The hydraulic driving pressure is greatly reduced; moreover, the stroke adjusting nut is arranged at the top and is matched with the bearing, so that the torque needing to be adjusted is reduced, and an operator can observe and adjust conveniently; in addition, by arranging the buffering piece, impact energy can be absorbed at the tail end of the closing stroke, and rigid collision is avoided; and the sand prevention pin is arranged in the pressure balance hole, so that opening friction force is reduced, sand grains are prevented from invading the sealing cavity, and the service life of the whole safety valve is prolonged.

Description

Technical Field

[0001] This invention relates to the field of oil and gas wellhead equipment technology, and in particular to a 210MPa surface safety valve. Background Technology

[0002] Surface safety valves (SSVs) are crucial safety devices in oil and gas wellhead control systems. Their core function is to rapidly shut off the wellhead fluid passage when abnormal conditions are detected, preventing accidents. According to GB / T 22513 or API 6A standards, for ultra-high pressure oil and gas fields, surface safety valves are required to reliably seal and actuate rapidly under pressure differentials of 210 MPa or even higher. However, conventional surface safety valves with existing technology face a series of severe technical challenges when dealing with such ultra-high pressure conditions: First, the piston and return spring are coaxially integrated, and the piston diameter is limited by the inner diameter of the spring, resulting in insufficient force-bearing area and driving pressure as high as 40-50 MPa, making the system complex and risky. Secondly, the stroke adjustment mechanism is built into the spring cavity, which makes it difficult for operators to touch and observe during installation and debugging. The adjustment process is cumbersome and relies on experience, making it impossible to achieve precise stepless adjustment. Third, the return spring of the ground safety valve usually has a large stiffness. When the pressure is released in an emergency, the huge energy released by the spring drives the piston and other components to return at high speed and collide violently with the end cover at the end of the stroke. The strong impact and vibration will not only generate noise, but also damage the structural integrity of the piston, seal and connecting components. Long-term action may lead to component fatigue failure, affecting the service life and reliability of the valve. Fourth, by opening balance holes on the valve plate, the pressure before and after the valve plate can be balanced and friction reduced. However, under harsh media conditions such as sand, these balance holes become channels for sand particles to enter the sealing cavity, causing the sealing pair to be eroded and scratched, thus accelerating failure and reducing the reliability of the valve.

[0003] Therefore, in order to solve the aforementioned technical problems, we propose a 210MPa ground safety valve. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to achieve a comprehensive performance improvement that includes low-pressure high-efficiency drive, top-mounted stepless stroke adjustment, smooth action buffering and fluid pressure balance, and sand prevention function.

[0005] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a 210MPa ground safety valve, which includes a flow-blocking assembly, including a valve body and a valve plate disposed in the valve body; A drive assembly for driving the flow-closing component to perform opening and closing actions includes a pressure cylinder, a piston cylinder sleeved outside the pressure cylinder, a piston disposed inside the piston cylinder, and a valve stem connected and cooperating with the piston; and, The valve stem is connected to the valve plate; by inputting a pressurizing medium into the pressure cylinder, the medium acts on the piston, and the piston and the piston cylinder can move axially relative to the valve body, thereby causing the valve plate to move.

[0006] In a preferred embodiment of the 210MPa ground safety valve of the present invention: the valve stem and the piston are connected by a limiting adjustment screw; and... The limit adjustment screw has a stroke adjustment nut at one end that passes through the piston, and a bearing is provided between the stroke adjustment nut and the piston.

[0007] In a preferred embodiment of the 210MPa ground safety valve of the present invention: the end of the stroke adjusting nut away from the piston is connected to the valve position indicator rod through a limiting nut.

[0008] In a preferred embodiment of the 210MPa ground safety valve of the present invention: the valve body is connected to the valve cover by a flange steel ring, the valve cover is connected to the spring cylinder by a connecting ring, and an upper cover is provided above the spring cylinder.

[0009] In a preferred embodiment of the 210MPa ground safety valve of the present invention: a hydraulic interface is provided on the outer wall of the upper cover, and the pressure cylinder is fixedly connected to the upper cover.

[0010] In a preferred embodiment of the 210MPa ground safety valve of the present invention: a pressure plate is provided on the outer wall of the piston cylinder, and a first spring is provided between the pressure plate and the connecting ring.

[0011] In a preferred embodiment of the 210MPa ground safety valve of the present invention: the upper cover is provided with a buffer, the buffer including a first screw connected to the upper cover.

[0012] In a preferred embodiment of the 210MPa ground safety valve of the present invention: a baffle is slidably provided on the outer wall of the first screw, a second spring is provided between the baffle and the upper cover, and the baffle is movably engaged with the pressure plate.

[0013] In a preferred embodiment of the 210MPa ground safety valve of the present invention: a limiting ring is provided on the piston cylinder, and the limiting ring is in movable cooperation with the piston.

[0014] In a preferred embodiment of the 210MPa ground safety valve of the present invention: a pressure balance hole is provided on the valve plate, a sand-proof pin is provided in the pressure balance hole, and a second screw is provided in the pressure balance hole and above the sand-proof pin.

[0015] The beneficial effects of this invention are as follows: by setting the piston and piston cylinder to be able to move axially relative to the valve body, the size constraint of the piston is released, and the force-bearing area of ​​the piston can be increased, so that the hydraulic drive pressure of the safety valve can be greatly reduced under the same opening force; furthermore, by placing the stroke adjusting nut at the top and cooperating with the bearing, the required adjustment torque is reduced, and it is also convenient for the operator to observe and adjust; in addition, by setting a buffer, the impact energy can be absorbed at the end of the closing stroke to avoid rigid collision; and, by setting a sand-proof pin inside the pressure balance hole, the opening friction is reduced while preventing sand particles from entering the sealing cavity. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 A schematic diagram of the overall structure of the 210MPa ground safety valve is shown. Figure 2 A cross-sectional view of the internal structure of a 210MPa ground safety valve is shown. Figure 3 An enlarged schematic diagram of a portion of the drive component structure is shown; Figure 4 An enlarged schematic diagram of the buffer connection structure is shown; Figure 5 A schematic diagram of a partial connection between the valve stem and the valve plate is shown. Figure 6 An enlarged schematic diagram of the sand-proof pin connection structure is shown; Figure 7 This diagram illustrates the displacement of a 210MPa ground safety valve from fully closed to fully open. Figure 8 A comparison diagram of the piston and piston cylinder connection of a conventional safety valve and the design of this invention is shown; Figure 9 A comparison diagram of the piston diameter dimensions of a conventional safety valve and the design of this invention is shown; Figure 10 A comparison diagram of the stroke adjusting nut arrangement of a conventional safety valve and the design of this invention is shown; Figure 11 A schematic diagram of the working state of the buffer is shown. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0018] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0019] Reference Figures 1-11 This embodiment provides a 210MPa ground safety valve, including a flow-stopping assembly 1, comprising a valve body 11 and a valve plate 12 disposed within the valve body 11. A valve seat 111 is provided within the valve body 11, and the valve seat 111 is movably engaged with the valve plate 12. Figure 2 As shown, the valve stem 24 is connected to the valve plate 12. The valve stem 24 can drive the valve plate 12 to move axially along the valve body 11. When the valve seat 111 and the channel on the valve plate 12 are connected, fluid can pass through.

[0020] A 210MPa ground safety valve also includes a drive assembly 2 for driving the shut-off assembly 1 to achieve opening and closing actions. The drive assembly 2 includes a pressure cylinder 21, a piston cylinder 22 sleeved outside the pressure cylinder 21, a piston 23 disposed inside the piston cylinder 22, and a valve stem 24 connected and cooperating with the piston 23, as detailed below. Figure 3 As shown, dynamic sealing can be used between the components. The piston 23 and the pressure cylinder 21 are arranged in parallel. In this scheme, the piston 23 is preferably located directly below the pressure cylinder 21. Furthermore, by inputting a pressurizing medium into the pressure cylinder 21, the medium acts on the piston 23, causing the piston 23 and piston cylinder 22 to move relative to the pressure cylinder 21. Specifically, they move along the axial direction of the valve body 11, thereby driving the valve stem 24 and the valve plate 12 to control the opening and closing of the flow-stopping assembly 1.

[0021] like Figure 8 As shown, the connection between piston C23 and piston cylinder C22 in a traditional safety valve adopts a "fixed piston-cylinder" design (left figure). That is, piston C23 and piston cylinder C22 are in a static fit relationship. Piston cylinder C22 and the top cover are integrally designed and fixed. Only piston C23 reciprocates under hydraulic pressure. However, the connection between piston 23 and piston cylinder 22 in our safety valve adopts a "dynamic piston-cylinder" system (right figure). That is, unlike the traditional safety valve, both piston 23 and piston cylinder 22 in our valve can move relative to each other. Through this design, the wear of the moving parts is shared, effectively extending the service life of piston 23 seal.

[0022] Furthermore, such as Figure 9 As shown, in traditional safety valves, the spring C151 is typically coaxially nested or arranged parallel to the piston C23. The installation space directly limits the maximum outer diameter D1 of the piston C23 (left figure). This structural coupling results in insufficient effective working area of ​​the piston C23. According to the formula P=F / S, with a constant required opening force F, the smaller the area S, the higher the required hydraulic drive pressure P, typically reaching around 50MPa, potentially leading to high-pressure leakage risks. However, due to the change in motion relationship, the installation position and space of the piston 23 can be redesigned, allowing the maximum outer diameter of the piston 23 to reach D2 (right figure). It is no longer directly limited by the installation space of the spring 151. Figure 9 As shown, the key dimensions of the spring, such as the mean diameter, cross-sectional diameter, and length, remain unchanged, but the diameter of the piston has been significantly increased from the traditional D1 to D2.

[0023] In one embodiment provided in this application, the valve stem 24 and the piston 23 are connected by a limiting adjustment screw 25; and a stroke adjustment nut 251 is provided at one end of the limiting adjustment screw 25 that passes through the piston 23, and a bearing 252 is provided between the stroke adjustment nut 251 and the piston 23.

[0024] In one embodiment provided in this application, the end of the stroke adjusting nut 251 away from the piston 23 is connected to the valve position indicator rod 253 via a limiting nut 2531.

[0025] like Figure 10 As shown, in traditional safety valves, the stroke adjusting nut C251 (left image) is located inside the spring C151. This layout makes it difficult for operators to access and observe during installation and commissioning, resulting in a cumbersome adjustment process that relies heavily on experience and cannot achieve precise stepless adjustment. In contrast, the stroke adjusting nut 251 of our safety valve (right image) is located on top of the hydraulic actuator, precisely between our piston 23, piston cylinder 22, and pressure cylinder 21. Compared to the traditional design, this cleverly provides space for installing the stroke adjusting nut 251 at the top, as this position is completely exposed and easily accessible. Furthermore… A high-load bearing 252 is introduced into the stroke adjusting nut 251, which transforms the traditional sliding friction into rolling friction. This significantly reduces the torque required to rotate the stroke adjusting nut 251, making operation easier and more flexible. Through this design, combined with the visibility of the top-mounted stroke adjusting nut 251 and the convenience provided by the bearing 252, operators can make continuous and precise stepless adjustments on the top of the hydraulic actuator using standard tools without any disassembly. The adjustment process of the stroke adjusting nut 251 is smooth, and the spring preload can be easily set and locked at the theoretically calculated optimal value.

[0026] In one embodiment provided in this application, the valve body 11 is connected to the valve cover 13 via a flange steel ring 131, the valve cover 13 is connected to the spring cylinder 15 via a connecting ring 14, and an upper cover 16 is provided above the spring cylinder 15. A hydraulic interface 161 is provided on the outer wall of the upper cover 16, and a first fixing plate 211 is provided on the outer wall of the pressure cylinder 21. The first fixing plate 211 is bolted to the upper cover 16, thereby realizing the fixed connection between the pressure cylinder 21 and the upper cover 16.

[0027] Among them, such as Figure 3 As shown, by inputting pressurized medium into the hydraulic interface 161, the medium enters the pressure cylinder 21 and acts on the piston 23, thereby causing the piston 23 to move axially relative to the valve body 11.

[0028] In one embodiment provided in this application, a pressure plate 221 is provided on the outer wall of the piston cylinder 22, and a first spring 151 is provided between the pressure plate 221 and the connecting ring 14.

[0029] Among them, such as Figure 3 As shown, the outer wall of the piston cylinder 22 is provided with a second fixing plate 223, and the pressure plate 221 is bolted to the second fixing plate 223, thereby realizing the connection between the pressure plate 221 and the piston cylinder 22.

[0030] In one embodiment provided in this application, such as Figure 4 As shown, the upper cover 16 is provided with a buffer 162, which includes a first screw 1621 connected to the upper cover 16.

[0031] One end of the first screw 1621 is fixedly connected to the upper cover 16, and the other end extends to the outside of the upper cover 16. The first screw 1621 provides a guiding function for the baffle 1622. Of course, in this application, it is not excluded that other connecting components, such as connecting columns, slides, sliders, etc., can be used to guide the baffle 1622.

[0032] In one embodiment provided in this application, a baffle 1622 is slidably provided on the outer wall of the first screw 1621, a second spring 1623 is provided between the baffle 1622 and the upper cover 16, and the baffle 1622 is movably engaged with the pressure plate 221.

[0033] Among them, such as Figure 4 As shown, a receiving cavity can be opened on the outer wall of the upper cover 16. The second spring 1623 is partially located in the receiving cavity. The second spring 1623 is sleeved on the outer wall of the first screw 1621. Under the action of the first spring 151, when the pressure plate 221 is reset, it contacts and cooperates with the baffle 1622, thereby achieving a buffering effect.

[0034] like Figure 11As shown, when the valve is in the open state, the second spring 1623 is in its natural length state (left figure). After the emergency closing command is issued, the drive assembly 2 performs a reset action. At this time, the system hydraulic pressure has been released, and the first spring 151 releases its stored elastic potential energy, driving the piston 23 and related moving components to move upward (towards the closing direction) at high speed. During most of the reset stroke, the buffer 162 has not yet intervened, and the piston 23 accelerates under the action of the first spring 151 until there is about 10mm left before the end of the stroke. When plate 221 begins to contact buffer 162 (right figure), it enters the buffering stage. After plate 221 contacts baffle 1622 and begins to compress the second spring 1623, it moves 10mm. Then, valve stem 24 reverses to seal and is positioned, and the stroke ends. At this time, the valve has reached the fully closed position in balance, without rigid impact or violent vibration. When it is necessary to execute the valve opening command, plate 221 will disengage from buffer 162, the second spring 1623 will return to its natural state, and baffle 1622 will contact the first screw 1621 to limit its movement and stop moving, preparing for the next buffering.

[0035] In one embodiment provided in this application, a limiting ring 222 is provided on the piston cylinder 22, and the limiting ring 222 is in movable cooperation with the piston 23, such as... Figure 3 As shown, when the piston 23 moves downward, the limiting ring 222 acts as abutment against the bottom of the piston 23, thereby driving the piston cylinder 22 to move downward as well.

[0036] In one embodiment provided in this application, a pressure balance hole 121 is provided on the valve plate 12, and a sand-proof pin 122 is provided in the pressure balance hole 121. A second screw 123 is also provided in the pressure balance hole 121 and above the sand-proof pin 122. The second screw 123 can abut against the sand-proof pin 122 to limit its movement. It mainly serves to prevent the sand-proof pin 122 from going upward. The installation connection leaves a gap so as not to affect the passage of high pressure medium.

[0037] Among them, such as Figure 5 As shown, the valve plate 12 and the valve stem 24 are connected by a T-slot. One end of the pressure balance hole 121 is connected to the fluid passage on the valve plate 12, and the other end is connected to the upper chamber of the valve seat 111 through the T-slot. The diameter of the pressure balance hole 121 near the fluid passage is smaller, and the sand-proof pin 122 is positioned above the smaller diameter hole to install the sand-proof pin 122 and prevent it from falling off. There is a small gap between the pressure balance hole 121 and the sand-proof pin 122, which allows the high-pressure medium to pass through while blocking sand particles from passing through.

[0038] like Figure 5 , Figure 6As shown, by setting the anti-sand pin 122, the function of allowing pressure to pass through and prohibiting sand particles from passing through is realized. When the valve is in the closed state, a small amount of high-pressure medium can slowly seep into and fill the upper chamber of the valve plate 12 through the tiny gap between the anti-sand pin 122 and the pressure balance hole 122. This process allows the pressure on the upper and lower sides to be pre-balanced before opening, thereby converting the huge static friction between the valve plate 12 and the valve seat 111 into a very small dynamic friction, so that the valve can be opened with a low hydraulic driving force.

[0039] Furthermore, during the pressure balancing process, solid sand particles in the medium move with the fluid to the inlet of the pressure balancing hole 121. Due to the extremely small gap between the sand-proof pin 122 and the hole wall, and the large size and irregular shape of the sand particles, they are effectively blocked outside the inlet of the pressure balancing hole 121 and cannot enter and scour or wear the precise main sealing surface between the valve plate 12 and the valve seat 111, thus ensuring the long-term reliability of the sealing pair.

[0040] It should be further noted that the ground safety valve designed in this paper is suitable for 210MPa ground safety valves, such as... Figure 7 As shown, the diagram illustrates two working states of the ground safety valve: fully closed (left) and fully open (right). The dimensions S marked in the diagram represent the movement of the valve position indicator rod 253, piston 23, limit adjustment screw 25, and valve plate 12, respectively. During the process of the ground safety valve moving from fully closed to fully open, the valve stem 24, first spring 151, pressure plate 221, and stroke adjusting nut 251 also move downward in a straight line.

[0041] In summary, when the valve chamber is pressurized, a certain amount of hydraulic pressure is pumped in through the hydraulic interface 161 to overcome the upward thrust F1 of the valve stem 24, the frictional force F2 between the valve plate 12 and the valve seat 111, the frictional force F3 between the valve stem 24 and the sealing packing, the initial preload of the first spring 151, and the spring force F4 during the compression process, thus pushing the piston 23 and the limit adjustment screw 25 downward. The piston 23 drives the piston cylinder 22 downward, and the piston cylinder 22 and the pressure plate 221 are connected as a whole through the second fixed plate 223, compressing the first spring 151 to move downward, and the limit adjustment screw... The upper part of piston 25 is connected to the stroke adjusting nut 251 and valve position indicator rod 253 to form a whole. The lower part of limit adjusting screw 25 is connected to the upper part of valve stem 24 by threads to form a whole. The lower part of valve stem 24 is connected to the upper part of valve plate 12 by T-slot to form a whole. Therefore, when piston 23 and limit adjusting screw 25 move downward linearly, they will drive valve stem 24 and valve plate 12 to move downward linearly, and at the same time compress the first spring 151 until limit adjusting screw 25 contacts the limiting device of connecting ring 14, and the movement stroke ends. In this way, the ground safety valve realizes a complete stroke from fully closed to fully open.

[0042] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A 210MPa ground safety valve, characterized in that: include, The flow-stopping assembly (1) includes a valve body (11) and a valve plate (12) disposed within the valve body (11). A drive assembly (2) for driving the flow-closing assembly (1) to perform opening and closing actions includes a pressure cylinder (21), a piston cylinder (22) sleeved outside the pressure cylinder (21), a piston (23) disposed inside the piston cylinder (22), and a valve stem (24) connected and cooperating with the piston (23); and, The valve stem (24) is connected to the valve plate (12); by inputting a pressurizing medium into the pressure cylinder (21), the medium acts on the piston (23), and the piston (23) and the piston cylinder (22) can move axially relative to the valve body (11), thereby causing the valve plate (12) to move.

2. The 210MPa ground safety valve according to claim 1, characterized in that: The valve stem (24) and the piston (23) are connected by a limiting adjustment screw (25); and, The limit adjustment screw (25) has a stroke adjustment nut (251) at one end that passes through the piston (23), and a bearing (252) is provided between the stroke adjustment nut (251) and the piston (23).

3. The 210MPa ground safety valve according to claim 2, characterized in that: The end of the stroke adjusting nut (251) away from the piston (23) is connected to the valve position indicator rod (253) via a limiting nut (2531).

4. The 210MPa ground safety valve according to claim 1 or 3, characterized in that: The valve body (11) is connected to the valve cover (13) via a flange steel ring (131), and the valve cover (13) is connected to the spring cylinder (15) via a connecting ring (14). The spring cylinder (15) is provided with an upper cover (16).

5. The 210MPa ground safety valve according to claim 4, characterized in that: The outer wall of the upper cover (16) is provided with a hydraulic interface (161), and the pressure cylinder (21) is fixedly connected to the upper cover (16).

6. The 210MPa ground safety valve according to claim 5, characterized in that: The piston cylinder (22) has a pressure plate (221) on its outer wall, and a first spring (151) is provided between the pressure plate (221) and the connecting ring (14).

7. The 210MPa ground safety valve according to claim 4, characterized in that: The upper cover (16) is provided with a buffer (162), the buffer (162) including a first screw (1621) connected to the upper cover (16).

8. The 210MPa ground safety valve according to claim 7, characterized in that: A baffle (1622) is slidably provided on the outer wall of the first screw (1621), and a second spring (1623) is provided between the baffle (1622) and the upper cover (16). The baffle (1622) is in movable cooperation with the pressure plate (221).

9. The 210MPa ground safety valve according to claim 1 or 6, characterized in that: The piston cylinder (22) is provided with a limiting ring (222), and the limiting ring (222) is in active cooperation with the piston (23).

10. The 210MPa ground safety valve according to any one of claims 1-3 and 5-8, characterized in that: The valve plate (12) is provided with a pressure balance hole (121), and a sand-proof pin (122) is provided in the pressure balance hole (121). A second screw (123) is also provided in the pressure balance hole (121) and above the sand-proof pin (122).

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