Force transmission structure for enhancing operational stability of high-pressure safety valve, and safety valve

Abstract

A force transmission structure for enhancing the operational stability of a high-pressure safety valve, and a safety valve, relating to the field of safety valve structures. The force transmission structure comprises a disc holder (3), a valve disc (4), a guide sleeve (6), and a steel ball (7), wherein the guide sleeve is provided with a limiting through hole; one end of the disc holder is mounted in the limiting through hole, the disc holder is slidably connected to the guide sleeve in the axial direction of the limiting through hole, and the other end of the disc holder is provided with a first mounting groove; the valve disc is mounted in the first mounting groove, and a second mounting groove is provided in the middle of the end face of the valve disc facing the bottom of the first mounting groove; and the steel ball is mounted between the disc holder and the valve disc, the steel ball being in contact with the bottom of the first mounting groove and the bottom of the second mounting groove. The force transmission structure ensures the setting stability of the safety valve under high-pressure operating conditions, achieving a setting pressure deviation of ≤3% and a setting pressure stability deviation within ±1%.

Description

A force transmission structure and safety valve for improving the operational stability of a high-pressure safety valve

[0001] This application claims priority to Chinese Patent Application No. 2024116277427, filed on November 14, 2024, entitled "A force transmission structure and safety valve for improving the stability of high-pressure safety valve operation", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention patent belongs to the field of safety valve structure design technology, specifically relating to a force transmission structure and safety valve for improving the operational stability of a high-pressure safety valve, thereby improving the operational stability of the safety valve under high-pressure conditions. Background Technology

[0003] Safety valves are important overpressure protection devices for pressure vessels and process systems. When the equipment reaches the set pressure of the safety valve, the safety valve automatically opens to discharge a rated amount of fluid, thereby reducing the equipment pressure and ensuring equipment safety.

[0004] Stable operation of safety valves is crucial for the smooth operation of protective equipment. According to ASME XIII, "Rules for Overpressure Protection," and GB / T 12243, "Spring-Loaded Safety Valves," the requirements for the stability of safety valve operation are as follows:

[0005] Table 1. Safety Valve Operation Stability Requirements

[0006] The common safety valve structure is shown in Figure 1. The spring direct load type safety valve is provided with preload by spring 1. The preload is transmitted step by step through valve stem 2, backflush disc 3, and valve disc 4, and finally forms pressure on the contact surface between valve disc 4 and valve seat 5, which is the set pressure.

[0007] When the system pressure is lower than the safety valve's set pressure, valve disc 4 is pressed against valve seat 5, and the safety valve is closed and remains sealed. When the system pressure is higher than the set pressure, the system pressure acting on valve disc 4 overcomes the spring preload, causing the safety valve to open. When the system pressure drops below the reseating pressure, the safety valve closes again.

[0008] As shown in Figure 2, a common safety valve force transmission structure consists of a valve stem 2, a backflush disc 3, and a valve disc 4. The point of action between the valve stem 2 and the backflush disc 3 is a, and the point of action between the backflush disc 3 and the valve disc 4 is b.

[0009] Due to factors such as the machining accuracy of parts, the fit tolerance of parts, and the assembly deviation, the spring preload cannot be guaranteed to be transmitted vertically, and both the recoil disc 3 and the valve disc 4 will bear a portion of the lateral force.

[0010] The magnitude of the lateral force directly affects the stability of the safety valve's operation, causing uneven pressure between the valve disc 4 and the valve seat 5, leading to premature leakage and opening of the safety valve, i.e., a larger setting deviation. In addition, the lateral force increases the friction between the backflush disc 3 and the guide sleeve 6, resulting in unstable operation of the safety valve.

[0011] As the safety valve's set pressure increases, the spring preload also increases, leading to a greater lateral force on the spring. This has a more significant impact on the stability of the set pressure, causing the operational stability to exceed standard requirements. Summary of the Invention

[0012] The technical problem solved by this application is to overcome the shortcomings of the prior art and provide a force transmission structure with a steel ball to improve the stability of high-pressure safety valve operation, so that the safety valve sets pressure deviation, safety valve sets pressure stability deviation and mechanical performance and other indicators meet the standard specifications under high pressure, and realize the stability and reliability of the safety valve's online operation performance.

[0013] The technical solution provided in this application is as follows:

[0014] A force transmission structure for improving the operational stability of a high-pressure safety valve includes a backflush disc, a valve disc, a guide sleeve, and a steel ball. The guide sleeve is provided with a limit through hole. One end of the backflush disc is installed in the limit through hole. The backflush disc and the guide sleeve are slidably connected along the axial direction of the limit through hole. The other end of the backflush disc is provided with a first mounting groove. The valve disc is installed in the first mounting groove. A second mounting groove is provided in the middle of the end face of the valve disc facing the bottom of the first mounting groove. The steel ball is installed between the backflush disc and the valve disc. The steel ball contacts the bottom of the first mounting groove and the bottom of the second mounting groove.

[0015] The first mounting groove includes a cylindrical groove and a conical groove located at the bottom of the cylindrical groove; the second mounting groove is conical in shape.

[0016] The cone angles of both the conical groove and the second mounting groove are 120°.

[0017] The outer circumferential surface of the valve disc is clearance-fitted with the recoil disc.

[0018] The difference between the diameter of the valve disc and the diameter of the cylindrical groove is between 0.05 and 0.1.

[0019] The distance from the contact point between the steel ball and the valve disc to the contact surface between the valve disc and the valve seat / the outer diameter of the valve disc = 0.3 to 0.5.

[0020] When the valve disc is coaxial with the first mounting groove, the steel ball is in contact with the bottom of the first mounting groove and the bottom of the second mounting groove, and the center of the steel ball is coaxial with the first mounting groove and the second mounting groove, the valve disc is not in contact with the inner wall of the first mounting groove.

[0021] A safety valve includes a valve body, a valve seat, a valve stem, a spring, and a force transmission structure described above for improving the operational stability of a high-pressure safety valve. The valve body has a valve cavity and has a first outlet, a second outlet, and a third outlet communicating with the valve cavity. A valve seat is connected to the first outlet of the valve body, and the second outlet is directly opposite the first outlet. A valve cover is connected to the second outlet of the valve body. The valve stem is slidably connected to the valve cover, and the spring is disposed outside the valve stem for driving the valve cover to move.

[0022] The force transmission structure includes a recoil disc, a valve disc, a guide sleeve, and a steel ball. The guide sleeve is fitted between the first outlet end of the valve body and the valve cover. The end of the valve stem is installed in the limiting through hole and contacts the end of the recoil disc. The valve disc is directly opposite the valve seat.

[0023] When the valve disc contacts the valve seat, the length of the backflush disc inserted into the guide sleeve is 0.2 to 0.4 times the diameter of the guide sleeve hole. This setting further lowers the center of gravity of the backflush disc.

[0024] In summary, this application includes at least the following beneficial technical effects:

[0025] The use of a new type of steel ball force transmission structure ensures the setting stability of the safety valve under high pressure conditions, achieving a setting pressure deviation of ≤3% and a setting pressure stability deviation of ±1%. Attached Figure Description

[0026] Figure 1. A common safety valve structure diagram;

[0027] Figure 2. Common force transmission structure diagram of safety valve;

[0028] Figure 3 shows the improved force transmission structure of the safety valve.

[0029] The following are the reference numerals: 1. Spring; 2. Valve stem; 3. Backflush disc; 4. Valve disc; 5. Valve seat; 6. Guide sleeve; 7. Steel ball. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0031] This application discloses a force transmission structure for improving the stability of high-pressure safety valve operation, as shown in Figure 3, including a spring 1, a valve stem 2, a backflush disc 3, a valve disc 4, a guide sleeve 6, and a steel ball 7.

[0032] The guide sleeve 6 is provided with a limiting through hole. One end of the recoil plate 3 is installed in the limiting through hole. The recoil plate 3 and the guide sleeve 6 are slidably connected along the axis of the limiting through hole. The other end of the recoil plate 3 is provided with a first mounting groove. The valve disc 4 is installed in the first mounting groove. The first mounting groove includes a cylindrical groove and a conical groove located at the bottom of the cylindrical groove. A second mounting groove is provided in the middle of the end face of the valve disc 4 facing the bottom of the first mounting groove. The second mounting groove is conical in shape, and the cone angle of both the conical groove and the second mounting groove is 120°. A steel ball 7 is installed between the recoil plate 3 and the valve disc 4. The steel ball 7 contacts the bottom of the conical groove and the second mounting groove, forming two line contacts. The end of the second mounting groove to the edge of the valve disc 4 is an annular surface with a width of 2-4 mm.

[0033] The outer circumferential surface of valve disc 4 and the recoil plate 3 are in clearance fit, meaning that valve disc 4 oscillates within the recoil plate 3 around the contact point between valve disc 4 and steel ball 7. The amplitude of this oscillation determines the stability and sealing of the safety valve. Through experiments with different oscillation amounts, it was ultimately determined that the optimal oscillation angle for valve disc is between 0.55° and 0.85°, thus determining the clearance between the outer circumferential surface of valve disc 4 and recoil plate 3 to be 0.2° to 0.335°. The diameter of steel ball 7 is determined based on the ratio of the distance from the contact point between steel ball 7 and valve disc 4 to the contact surface between valve disc 4 and valve seat 5 to the outer diameter of valve disc 4.

[0034] When the valve disc 4 contacts the valve seat 5, the end of the backflush disc 3 inserted into the guide sleeve 6 is the force-bearing point position A. The distance between the force-bearing point position A and the end of the limiting through hole facing the valve seat 5 is 5 to 10 mm.

[0035] By adding a steel ball 7 between the recoil plate 3 and the valve disc 4, the self-aligning ability of the valve disc 4 is enhanced by the variable position of the steel ball 7. At the same time, the position A of the force point between the valve stem 2 and the recoil plate 3 is reduced, thereby reducing the influence of lateral force on the recoil plate 3 and the valve disc 4, thus ensuring the stability of the safety valve's operation.

[0036] The force transmission structure of this patent features a dual force transmission point design with steel balls: a dual force transmission point design with steel balls 7 in line contact is adopted between the recoil plate 3 and the valve disc 4. The first force transmission point is located between the steel ball 7 and the recoil plate 3, and the second force transmission point is located between the steel ball 7 and the valve disc 4, both of which are in line contact.

[0037] During the setting, opening, discharging, and reseating processes of the safety valve, the lateral force acting on the backwash plate 3 will pass through the steel ball 7 when it is transmitted to the valve disc 4. The position of the steel ball 7 can change slightly, which enhances the self-aligning ability of the valve disc 4 and thus reduces the influence of the lateral force.

[0038] ② Design of the relationship between the force-bearing point and the center of gravity of the valve disc: As shown in Figure 3, according to the calculation formula of the annular disk in the "Mechanical Design Handbook", the thickness of the valve disc under different pressure levels is calculated. Under the premise of ensuring strength, the thickness of the valve disc 4 is reduced, and a steel ball 7 of appropriate size is added between the recoil plate 3 and the valve disc 4. The force-bearing point of the valve disc 4 and the steel ball 7 is determined by the ratio of the distance from the contact point of the steel ball 7 and the valve disc 4 to the valve disc 4 and the valve seat 5 to the outer diameter of the valve disc 4. The ratio needs to be below 0.5, and the distance between the force-bearing point of the valve disc 4 and the center of gravity of the valve disc 4 is kept within 4.5mm, thereby increasing the stability of force transmission.

[0039] ③ Design of the force-bearing point of the recoil plate: As shown in Figure 3, adjust the position A of the force-bearing point between the valve stem 2 and the recoil plate 3, and move it down by an appropriate distance Y to reduce the force transmission point and reduce the influence of lateral force on the recoil plate 3.

[0040] A safety valve includes a valve body, a valve seat 5, a valve stem 2, a spring 1, and the aforementioned force transmission structure. The valve body has a valve cavity and three outlets communicating with the valve cavity: a first outlet, a second outlet, and a third outlet. The valve seat 5 is connected to the first outlet of the valve body, the second outlet is opposite to the first outlet, and a valve cover is connected to the second outlet. The valve stem 2 is slidably connected to the valve cover. The spring 1 is located outside the valve stem 2 and is used to drive the valve cover to move. The force transmission structure includes a back pressure plate 3, a valve disc 4, a guide sleeve 6, and a steel ball 7. The guide sleeve 6 is engaged between the first outlet end of the valve body and the valve cover. The end of the valve stem 2 is installed in a limiting through-hole and contacts the end of the back pressure plate 3. The valve disc 4 is opposite to the valve seat 5.

[0041] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

[0042] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

1. A force transmission structure for improving the stability of the action of a high-pressure safety valve, characterized by: It includes a backflush disc (3), a valve disc (4), a guide sleeve (6), and a steel ball (7). The guide sleeve (6) is provided with a limit through hole. One end of the backflush disc (3) is installed in the limit through hole. The backflush disc (3) and the guide sleeve (6) are slidably connected along the axis of the limit through hole. The other end of the backflush disc (3) is provided with a first mounting groove. The valve disc (4) is installed in the first mounting groove. A second mounting groove is provided in the middle of the end face of the valve disc (4) facing the bottom of the first mounting groove. The steel ball (7) is installed between the backflush disc (3) and the valve disc (4). The steel ball (7) is in contact with the bottom of the first mounting groove and the bottom of the second mounting groove.

2. The force transmission structure for improving the stability of the action of a high-pressure safety valve according to claim 1, characterized in that: The first mounting groove includes a cylindrical groove and a conical groove located at the bottom of the cylindrical groove; the second mounting groove is conical in shape.

3. The force transmission structure for improving the stability of the action of a high-pressure safety valve according to claim 2, characterized in that: The cone angles of both the conical groove and the second mounting groove are 120°.

4. The force transmission structure for improving the stability of the action of a high-pressure safety valve according to claim 2, characterized in that: The outer peripheral surface of the valve disc (4) and the recoil disc (3) are in clearance fit.

5. The force transmission structure for improving the stability of the action of a high-pressure safety valve according to claim 4, characterized in that: The difference between the diameter of the valve disc (4) and the diameter of the cylindrical groove is between 0.05 and 0.

1.

6. The force transmission structure for improving the stability of the action of a high-pressure safety valve according to claim 1, characterized in that: The distance from the contact point between the steel ball (7) and the valve disc (4) to the contact surface between the valve disc (4) and the valve seat (5) / the outer diameter of the valve disc (4) = 0.3 to 0.

5.

7. The force transmission structure for improving the stability of the operation of a high-pressure safety valve according to claim 1, characterized in that: When the valve disc (4) is coaxial with the first mounting groove, the steel ball (7) is in contact with the bottom of the first mounting groove and the bottom of the second mounting groove, and the center of the steel ball (7) is coaxial with the first mounting groove and the second mounting groove, the valve disc (4) does not contact the inner wall of the first mounting groove.

8. A relief valve characterized by: The valve body includes a valve body, a valve seat (5), a valve stem (2), a spring (1), and a force transmission structure for improving the stability of the operation of a high-pressure safety valve as described in any one of claims 1-7. The valve body has a valve cavity, a first outlet, a second outlet, and a third outlet that communicate with the valve cavity. The valve seat (5) is connected to the first outlet of the valve body, the second outlet is opposite to the first outlet, and the valve cover is connected to the second outlet of the valve body. The valve stem (2) is slidably connected to the valve cover. The spring (1) is located outside the valve stem (2) and is used to drive the valve cover to move. The force transmission structure includes a backflush disc (3), a valve disc (4), a guide sleeve (6), and a steel ball (7). The guide sleeve (6) is engaged between the first outlet end of the valve body and the valve cover. The end of the valve stem (2) is installed in the limiting through hole and contacts the end of the backflush disc (3). The valve disc (4) is opposite to the valve seat (5).

9. The safety valve of claim 9, wherein: When the valve disc (4) contacts the valve seat (5), the length of the backflush disc (3) inserted into the guide sleeve (6) is 0.2 to 0.4 times the diameter of the guide sleeve (6).

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