Low temperature top entry ball valve with pre-tightened seat

Abstract

The utility model discloses a low temperature upper ball valve of valve seat pre -tightening relates to valve technical field, aiming at the problem of existing spring adjustment pre -tightening force complicated etc. Including threaded bush and disc spring, threaded bush is connected on the valve seat with screw thread, and disc spring is equipped with on the valve seat outside, and the both ends of disc spring abut respectively on threaded bush and the inner wall of valve body, and the axial position of valve seat and the pre -tightening force of disc spring can be adjusted through rotating threaded bush, the outer peripheral surface of threaded bush is provided with a plurality of positioning slot, and the bottom of valve cover is equipped with the radial outward protruding limit platform, when the valve cover is covered on the valve body, the limit platform is embedded in the positioning slot, to limit the circumferential rotation of threaded bush, and the limit platform can slide along the axial direction with the positioning slot between relatively. Rotating threaded bush can adjust pre -tightening force on line, and the operation is simple, and disc spring is small in the change of elastic modulus under low temperature, and the pre -tightening force is stable and durable, and the limit platform cooperates with the positioning slot and can effectively prevent threaded bush loosening, simultaneously does not affect the axial floating of valve seat, guarantees the sealing compensation ability.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, and in particular to a cryogenic top-loading ball valve with pre-tightened valve seat. Background Technology

[0002] Cryogenic top-loading ball valves are mainly used for the transportation and control of cryogenic media such as liquefied natural gas, liquid oxygen, liquid nitrogen, and liquid argon. Under cryogenic conditions, the valve components undergo varying degrees of thermal expansion and contraction due to temperature changes, causing variations in the sealing pressure between the valve seat and the ball. If the sealing pressure is too low, media leakage will occur; if the sealing pressure is too high, it will increase the rotational torque of the ball and may even lead to excessive wear of the sealing surface, affecting the valve's service life.

[0003] To address the aforementioned problems, existing technologies typically incorporate an energy storage ring and a spring between the valve seat and the valve body. The spring's elastic force provides preload to the valve seat, compensating for material shrinkage at low temperatures. However, existing valve seat preload structures have the following drawbacks: First, adjusting the preload is difficult. In existing technologies, the spring preload is typically set once during assembly and cannot be adjusted online after assembly. If the preload is set incorrectly, the spring must be disassembled, replaced, and readjusted, which is cumbersome.

[0004] Secondly, the preload stability is poor. In low-temperature environments, the elastic modulus of the spring changes, leading to a decrease in preload. Simultaneously, during long-term use, wear on the sealing surface of the valve also gradually reduces the preload, making it impossible to guarantee long-term stable sealing performance.

[0005] Secondly, the accumulator ring is prone to detachment. In low-temperature environments, the elasticity of the accumulator ring decreases significantly. In existing technologies, the accumulator ring is usually installed in the annular groove of the valve seat only through an interference fit, without any additional fixing measures. The accumulator ring is prone to detaching from the groove under the influence of medium pressure and temperature changes, leading to seal failure. Utility Model Content

[0006] The purpose of this utility model is to address the problems of cumbersome spring adjustment of preload force and energy storage coil detachment in existing products, and to provide a low-temperature top-mounted ball valve with preloaded valve seat.

[0007] The technical solution of this utility model includes a valve body, a valve cover, a ball, a valve seat, and an energy storage ring. The valve seat is axially movable and installed in the valve body. The valve seat has a sealing surface that mates with the ball. The energy storage ring is installed between the outer periphery of the valve seat and the inner wall of the valve body. It also includes a threaded sleeve and a disc spring. The threaded sleeve is threaded onto the valve seat, and the disc spring is sleeved on the outside of the valve seat. The two ends of the disc spring abut against the threaded sleeve and the inner wall of the valve body, respectively. The axial position of the valve seat and the preload of the disc spring can be adjusted by rotating the threaded sleeve. The outer periphery of the threaded sleeve has multiple positioning grooves. The bottom of the valve cover has a radially outward protruding limiting platform. When the valve cover is closed on the valve body, the limiting platform is embedded in the positioning groove to restrict the circumferential rotation of the threaded sleeve. The limiting platform and the positioning groove can slide relative to each other axially.

[0008] By adopting the above technical solution, on the one hand, the axial position of the valve seat and the preload of the disc spring can be adjusted simultaneously by rotating the threaded sleeve, solving the problem that the preload cannot be adjusted online and the spring can only be disassembled and replaced in the prior art. The operation is simple and the sealing pressure can be accurately adjusted according to the actual working conditions during the assembly stage, avoiding problems caused by excessive or insufficient preload. On the other hand, using a disc spring as the preload element, compared with ordinary cylindrical springs, the disc spring has a smaller change in elastic modulus at low temperatures and a slower preload decay, which can provide a long-term stable preload and effectively compensate for material shrinkage and sealing surface wear under low-temperature conditions. In addition, the limiting platform at the bottom of the valve cover is embedded in the positioning groove of the threaded sleeve, which can reliably limit the circumferential rotation of the threaded sleeve and prevent the threaded sleeve from loosening due to vibration, medium pressure fluctuations and other factors during valve use, thereby ensuring the long-term stability of the preload. At the same time, the limiting platform and the positioning groove can slide relative to each other along the axial direction without affecting the axial movement of the valve seat, ensuring that the valve seat can perform normal elastic floating compensation and sealing surface fit adjustment.

[0009] In one possible design, multiple limiting grooves are also provided on the outer circumferential surface of the valve seat. The limiting grooves correspond to the positioning grooves in the circumferential position. The limiting platform extends along the axial direction of the valve cover, so that its end passes through the positioning groove and is inserted into the limiting groove to restrict the circumferential rotation of the valve seat. The limiting platform and the limiting groove can slide relative to each other in the axial direction.

[0010] The above design utilizes the same limiting platform to simultaneously achieve circumferential limiting of the threaded sleeve and valve seat. The structure is compact and eliminates the need for an additional independent circumferential limiting component for the valve seat, simplifying the overall structure. It effectively prevents the valve seat from rotating circumferentially under the influence of medium pressure fluctuations and repeated rotation of the ball, avoiding changes in the preload caused by circumferential movement of the valve seat. At the same time, the limiting platform and the limiting groove can slide relative to each other axially without affecting the axial movement function of the valve seat, ensuring that the sealing compensation capability of the valve seat remains unaffected.

[0011] In one possible design, the number of limiting platforms is the same as the number of threaded sleeves, and multiple positioning grooves are distributed along the circumference of the threaded sleeves. When the valve cover is closed on the valve body, the limiting platform is embedded in a positioning groove that is aligned with its circumferential position.

[0012] With the above design, a one-to-one alignment and embedding relationship is formed between the limiting stage and the positioning groove, which clarifies the cooperation method between the limiting stage and the threaded sleeve, ensuring the accuracy and reliability of circumferential positioning. The structure is simple and easy to assemble.

[0013] In one possible design, a retaining ring and a pin are also included; the outer circumferential surface of the valve seat is provided with an annular stepped groove, the energy storage ring is installed in the annular stepped groove, and the retaining ring is installed in the annular stepped groove and located on the side of the energy storage ring away from the ball in the axial direction; a pin hole is opened on the valve seat, the pin hole passes through the retaining ring, and the pin passes through the pin hole to position and connect the retaining ring and the valve seat.

[0014] By adopting the above design, the accumulator ring is axially limited by a retaining ring, and then the retaining ring is fixedly connected to the valve seat by a pin, forming a double fixing structure. This effectively solves the problem in the prior art where the accumulator ring is fixed only by an interference fit and is prone to falling off after its elasticity decreases in low-temperature environments. Even under harsh working conditions such as low-temperature medium impact and frequent pressure fluctuations, the accumulator ring can be reliably kept in the annular stepped groove, effectively preventing the retaining ring from excessive displacement or being pushed out under high-pressure medium impact, ensuring the integrity and reliability of the sealing system, and avoiding sealing failure caused by the accumulator ring falling off.

[0015] In one possible design, the pin is a cotter pin, which is a hollow cylinder with an axially open groove, and is elastically held in place within the pin hole.

[0016] With the above design, the elastic cotter pin is fixed in the pin hole by its own elastic tension, making installation convenient and quick without the need for additional fasteners; at the same time, the elastic cotter pin is not easy to loosen when subjected to external impact, which further improves the reliability of the retaining ring positioning and can still maintain a good fixing effect under low temperature conditions.

[0017] In one possible design, the disc spring is a single disc spring, or a disc spring assembly consisting of multiple disc springs stacked together.

[0018] By adopting the above design, a single disc spring or a combination of disc springs of different numbers and in different ways can be flexibly selected according to different valve specifications, working pressure and low temperature conditions to obtain the required preload and compensation stroke, thereby expanding the application range of the valve and meeting the sealing requirements under various complex working conditions.

[0019] In one possible design, the positioning groove is a long groove extending axially along the threaded sleeve, allowing the limiting stage to slide axially within the positioning groove.

[0020] The above design clarifies the structural form of the positioning groove, ensuring that while the limiting platform reliably restricts the circumferential rotation of the threaded sleeve, it can slide freely axially within the positioning groove without interfering with the axial movement of the valve seat and the threaded sleeve. This ensures that the valve seat can perform normal axial compensation as the medium pressure changes and the sealing surface wears, maintaining a stable sealing pressure ratio. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of Embodiment 1 of the present utility model; Figure 2 This is a partial structural schematic diagram of Embodiment 1 of the present utility model; Figure 3 This is a cross-sectional view of the main part of Embodiment 1 of this utility model; Figure 4 This utility model Figure 3 Exploded view; Figure 5 This is a schematic diagram of the main structure of the second embodiment of the present invention; Among them, 1. Valve body; 2. Valve cover; 21. Limiting platform; 3. Ball; 4. Valve seat; 41. Sealing surface; 42. Limiting groove; 43. Annular stepped groove; 44. Pin hole; 5. Energy storage ring; 6. Threaded sleeve; 61. Positioning groove; 7. Disc spring; 8. Retaining ring; 9. Pin. Detailed Implementation Example 1

[0022] like Figures 1 to 4 The illustrated cryogenic top-mounted ball valve with pre-tightened valve seat includes a valve body 1, a valve cover 2, a ball 3, a valve seat 4, an accumulator ring 5, a threaded sleeve 6, and a disc spring 7. The valve body 1 is a top-mounted structure with an opening at its top. The valve cover 2 is detachably bolted to the opening at the top of the valve body 1, forming a closed valve cavity. The ball 3 is rotatably mounted within the valve cavity, with its top fixedly connected to a valve stem. The valve stem extends upward through the valve cover 2 to drive the ball 3 to rotate, thus opening and closing the valve. Two valve seats 4 are annular structures, located on either side of the ball 3, and both are axially movable within the valve body 1. Each valve seat 4 has a sealing surface 41 on its side facing the ball 3, which is adapted to the surface of the ball 3. The sealing surface 41 is tightly fitted to the surface of the ball 3 to form the primary seal. The accumulator ring 5 is installed between the outer circumferential surface of the valve seat 4 and the inner wall of the valve body 1 to provide an auxiliary seal between the valve seat 4 and the valve body 1.

[0023] Each valve seat 4 has an external threaded section machined on its outer circumferential surface. The threaded sleeve 6 is a ring-shaped nut structure, with an internal thread machined on its inner circumferential surface to match the external threaded section of the valve seat 4. The threaded sleeve 6 is screwed onto the external threaded section of the valve seat 4 via a threaded connection. A disc spring 7 is sleeved on the outer circumference of the valve seat 4 and located between the threaded sleeve 6 and the inner wall of the valve body 1. One end of the disc spring 7 abuts against the end face of the threaded sleeve 6 facing the valve body 1, and the other end abuts against the stepped surface of the inner wall of the valve body 1. By rotating the threaded sleeve 6, the axial position of the threaded sleeve 6 on the valve seat 4 can be changed, thereby simultaneously achieving two adjustment functions: first, pushing the valve seat 4 axially to adjust the initial contact gap between the sealing surface 41 of the valve seat 4 and the ball 3; second, compressing or releasing the disc spring 7 to precisely adjust the preload applied by the disc spring 7 to the valve seat 4. This adjustment method does not require disassembling the internal components of the valve, and the sealing pressure can be accurately set according to the actual working conditions during the assembly stage, making the operation simple and efficient.

[0024] Using a disc spring 7 as the preload element offers significant advantages over traditional cylindrical helical springs. The disc spring 7 exhibits minimal change in its elastic modulus at low temperatures, with a slow rate of preload decay, maintaining stable elastic properties over extended periods at temperatures as low as -196℃. Simultaneously, the disc spring 7 exhibits small deformation while possessing high load-bearing capacity, providing sufficient preload within limited installation space. This effectively compensates for thermal expansion and contraction of components under low-temperature conditions, as well as wear on the sealing surface 41 during long-term valve use, ensuring a consistently appropriate sealing pressure between the valve seat 4 and the ball 3.

[0025] To prevent the threaded sleeve 6 from loosening and rotating due to vibration, medium pressure fluctuations, or other factors during valve use, thus reducing the preload, this invention incorporates a circumferential limiting structure between the threaded sleeve 6 and the valve cover 2. Multiple positioning grooves 61 are formed on the outer circumferential surface of the threaded sleeve 6, evenly distributed along its circumference. A radially outwardly protruding limiting platform 21 is integrally formed at the bottom of the valve cover 2. The number of limiting platforms 21 corresponds to the number of threaded sleeves 6, and their positions are circumferentially aligned with the positioning grooves 61 on the threaded sleeve 6. When the valve cover 2 is fitted onto the valve body 1, the limiting platform 21 precisely embeds into the corresponding positioning groove 61, thereby restricting the circumferential rotation of the threaded sleeve 6. Simultaneously, the positioning groove 61 is an elongated groove extending axially along the threaded sleeve 6, allowing the limiting platform 21 and the positioning groove 61 to slide relative to each other axially. This prevents interference with the axial floating of the valve seat 4 and the threaded sleeve 6, ensuring that the valve seat 4 can properly perform elastic floating compensation and sealing surface 41 fit adjustment.

[0026] To address the problem of the energy storage ring 5 easily detaching in low-temperature environments in existing technologies, this invention improves the fixing structure of the energy storage ring 5. The outer circumferential surface of the valve seat 4 is provided with an annular stepped groove 43, within which the energy storage ring 5 is installed. It also includes a retaining ring 8 and a pin 9. The retaining ring 8 is installed within the annular stepped groove 43 and located on the side of the energy storage ring 5 axially away from the ball 3, serving to axially limit the energy storage ring 5. A pin hole 44 is radially formed on the valve seat 4, with its inner end penetrating the annular stepped groove 43 and extending into the retaining ring 8. The pin 9 passes through the pin hole 44, positioning the retaining ring 8 to the valve seat 4 and preventing the retaining ring 8 from detaching from the annular stepped groove 43 under medium pressure. When the pressure inside the valve body 1 rises abnormally, the medium pressure acts on the accumulator ring 5, which transmits the axial thrust to the retaining ring 8. The retaining ring 8 then transmits the force to the valve seat 4 through the pin 9, thereby effectively preventing the retaining ring 8 and the accumulator ring 5 from being pushed out and falling off, ensuring the integrity and reliability of the sealing system.

[0027] The pin 9 is a flexible cotter pin, which is a hollow cylindrical structure with an axially open groove. During installation, the flexible cotter pin is inserted into the pin hole 44, and is fixed in place by the tightening force generated by its own elastic deformation. No additional fasteners such as nuts or washers are required, simplifying the assembly process. The elastic tightening effect of the flexible cotter pin effectively prevents it from loosening or falling off due to vibration during valve use, maintaining good fixation even under low-temperature conditions, ensuring the installation reliability of the retaining ring 8 and the energy storage ring 5.

[0028] To meet the needs of valves of different specifications and operating conditions, the disc spring 7 can be a single disc spring 7 or a disc spring group composed of multiple disc springs 7 stacked together. By adjusting the stacking method and number of disc springs 7, the required preload and compensation stroke can be flexibly obtained, thus expanding the applicability of the valve. Example 2

[0029] Unlike Example 1, as Figure 5As shown, multiple limiting grooves 42 are also provided on the outer circumferential surface of the valve seat 4. The number of limiting grooves 42 is the same as the number of positioning grooves 61, and they correspond one-to-one with the positioning grooves 61 in the circumferential position. The limiting platform 21 extends downward along the axial direction of the valve cover 2, so that its end passes through the positioning groove 61 of the threaded sleeve 6 and is inserted into the limiting groove 42 of the valve seat 4. This structure uses the same limiting platform 21 to simultaneously achieve circumferential limiting of the threaded sleeve 6 and the valve seat 4, without the need for additional independent circumferential limiting components for the valve seat 4. The structure is compact and simplifies the overall design. In this way, through a single limiting platform 21, dual circumferential limiting of the threaded sleeve 6 and the valve seat 4 is achieved simultaneously, effectively preventing the valve seat 4 from circumferentially rotating under the action of medium pressure fluctuations and repeated rotation of the ball 3, and avoiding changes in the preload of the disc spring 7 or a decrease in the fitting accuracy of the sealing surface 41 due to the circumferential rotation of the valve seat 4. At the same time, the limiting platform 21 and the limiting groove 42 can also slide relative to each other in the axial direction, without affecting the axial movement function of the valve seat 4.

[0030] The assembly process of this utility model is as follows: First, the disc spring 7 is sleeved on the outside of the valve seat 4, and the threaded sleeve 6 is threaded onto the valve seat 4. The energy storage ring 5 and the retaining ring 8 are sequentially installed into the annular stepped groove 43, and the retaining ring 8 is positioned and connected to the valve seat 4 with the pin 9 to complete the assembly of the valve seat 4 assembly. Then, the valve seat 4 assembly is installed into the inner cavity of the valve body 1. Next, the ball 3 is installed into the valve body 1, and the threaded sleeve 6 is rotated to adjust the axial position of the valve seat 4 and the preload of the disc spring 7 so that the sealing surface 41 of the valve seat 4 and the ball 3 obtain a suitable sealing pressure ratio. After the threaded sleeve 6 is adjusted to the position, the valve cover 2 is placed on the valve body 1. The limiting platform 21 at the bottom of the valve cover 2 is inserted into the positioning groove 61 on the threaded sleeve 6, which is located at the top and aligned with its circumferential position. If the valve seat 4 is provided with a limiting groove 42, the limiting platform 21 is inserted into the limiting groove 42 at the same time to complete the assembly. When online maintenance or replacement of internal valve components is required, simply remove the valve cover 2 to remove the components from above the valve body 1. There is no need to remove the valve body 1 from the pipeline, making the operation convenient and quick.

[0031] The working principle of this utility model is as follows: Under low-temperature conditions, valve components will shrink and deform due to the temperature drop. At this time, the disc spring 7 releases its stored elastic potential energy, pushing the threaded sleeve 6 and valve seat 4 to move axially, compensating for the shrinkage of the components and ensuring that the sealing surface 41 of the valve seat 4 always fits tightly against the surface of the ball 3, maintaining a stable sealing pressure. When the valve experiences wear on the sealing surface 41 due to prolonged use, the disc spring 7 can also automatically push the valve seat 4 to move axially, compensating for the wear and extending the valve's service life.

[0032] During valve opening and closing, the ball 3 rotates around the valve stem axis, generating relative friction with the sealing surface 41 of the valve seat 4. Since the limiting platform 21 of the valve cover 2 simultaneously restricts the circumferential rotation of both the threaded sleeve 6 and the valve seat 4, the valve seat 4 does not rotate with the ball 3, thus avoiding uneven wear of the sealing surface 41. Simultaneously, the axial sliding fit between the limiting platform 21 and the positioning groove 61 and limiting groove 42 ensures that the valve seat 4 can freely perform axial floating compensation.

[0033] The accumulator ring 5 forms a reliable auxiliary seal between the valve seat 4 and the valve body 1, preventing media leakage from the gap between the valve seat 4 and the valve body 1. The double fixing structure composed of the retaining ring 8 and the elastic cotter pin ensures that the accumulator ring 5 will not fall out of the annular stepped groove 43 under the conditions of low temperature media impact and frequent pressure fluctuations, thus guaranteeing the long-term reliability of the sealing system.

Claims

1. A cryogenic top-mounted ball valve with pre-tightened valve seat, comprising a valve body (1), a valve cover (2), a ball (3), a valve seat (4), and an energy storage ring (5), wherein the valve seat (4) is axially movable and installed inside the valve body (1), the valve seat (4) has a sealing surface (41) that mates with the ball (3), and the energy storage ring (5) is installed between the outer periphery of the valve seat (4) and the inner wall of the valve body (1); characterized in that, It also includes a threaded sleeve (6) and a disc spring (7). The threaded sleeve (6) is threaded onto the valve seat (4), and the disc spring (7) is sleeved on the outside of the valve seat (4). The two ends of the disc spring (7) abut against the inner wall of the threaded sleeve (6) and the valve body (1) respectively. By rotating the threaded sleeve (6), the axial position of the valve seat (4) and the preload of the disc spring (7) can be adjusted. The outer circumferential surface of the threaded sleeve (6) is provided with multiple positioning grooves (61), and the bottom of the valve cover (2) is provided with a radially outward protruding limiting platform (21). When the valve cover (2) is closed on the valve body (1), the limiting platform (21) is embedded in the positioning groove (61) to restrict the circumferential rotation of the threaded sleeve (6), and the limiting platform (21) and the positioning groove (61) can slide relative to each other along the axial direction.

2. The cryogenic top-mounted ball valve with pre-tightened valve seat according to claim 1, characterized in that, The valve seat (4) is also provided with a plurality of limiting grooves (42) on its outer peripheral surface. The limiting grooves (42) correspond to the positioning grooves (61) in the circumferential position. The limiting platform (21) extends along the axial direction of the valve cover (2) so that its end passes through the positioning groove (61) and is inserted into the limiting groove (42) to restrict the circumferential rotation of the valve seat (4). The limiting platform (21) and the limiting grooves (42) can slide relative to each other in the axial direction.

3. The cryogenic top-mounted ball valve with pre-tightened valve seat according to claim 1, characterized in that, The number of limiting platforms (21) is the same as the number of threaded sleeves (6). Multiple positioning grooves (61) are distributed along the circumference of the threaded sleeves (6). When the valve cover (2) is closed on the valve body (1), the limiting platform (21) is embedded in one of the positioning grooves (61) that is aligned with its circumferential position.

4. The cryogenic top-mounted ball valve with pre-tightened valve seat according to claim 1, characterized in that, It also includes a retaining ring (8) and a pin (9); the outer circumferential surface of the valve seat (4) is provided with an annular stepped groove (43), the energy storage ring (5) is installed in the annular stepped groove (43), the retaining ring (8) is installed in the annular stepped groove (43) and is located on the side of the energy storage ring (5) away from the sphere (3) in the axial direction; the valve seat (4) is provided with a pin hole (44), the pin hole (44) passes through the retaining ring (8), and the pin (9) passes through the pin hole (44) to position and connect the retaining ring (8) and the valve seat (4).

5. The cryogenic top-mounted ball valve with pre-tightened valve seat according to claim 4, characterized in that, The pin (9) is an elastic cotter pin, which is a hollow cylinder with an axial opening groove, and is elastically supported in the pin hole (44).

6. The cryogenic top-mounted ball valve with pre-tightened valve seat according to any one of claims 1 to 4, characterized in that, The disc spring (7) is a single disc spring (7) or a group of disc springs (7) consisting of multiple disc springs (7) stacked together.

7. The cryogenic top-mounted ball valve with pre-tightened valve seat according to any one of claims 1 to 4, characterized in that, The positioning groove (61) is a long groove extending axially along the threaded sleeve (6) to allow the limiting platform (21) to slide axially within the positioning groove (61).

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