Valve sealing structure and ultra-low temperature ball valve

Abstract

The valve sealing structure comprises a valve seat and a valve body, which cooperate to form a sealing element mounting area, the sealing element mounting area is U-shaped, and a flexible sealing element is adapted to be mounted in the sealing element mounting area; a supporting ring is arranged at an opening of the U-shaped sealing element mounting area, and a front end of the supporting ring abuts against the sealing element to deform the sealing element to two sides of the U-shaped sealing element mounting area. The application further discloses an ultralow-temperature ball valve which applies the valve sealing structure. The application has the advantages that: 1, the lip-shaped sealing ring can effectively cope with the cold shrinkage of metal parts; 2, the supporting ring is inserted between the two lips of the lip-shaped sealing ring to prevent the two lips from retracting; 3, the supporting ring abuts against the radial deformation of the sealing ring spring, and the sealing effect is more reliable; and 4, the compression ring spring cooperates with the supporting ring compression ring to prevent the supporting ring from retracting.

Description

Technical Field

[0001] This utility model relates to the field of valves, specifically a valve sealing structure and an ultra-low temperature ball valve using the valve sealing structure. Background Technology

[0002] In recent years, LNG has become a key industry in the national energy strategy, and the requirements for valves in liquefied natural gas (LNG) receiving terminals are becoming increasingly stringent. Since LNG is transported after being liquefied under ultra-low temperature pressure, valves in LNG receiving terminals need to operate under ultra-low temperature conditions. Chinese patent document CN217056411U, published on July 26, 2022, discloses a valve seat structure for an ultra-low temperature metal hard-seal floating ball valve, including a valve body and a ball disposed in the cavity of the valve body. A floating valve seat is disposed between the valve body and the ball, and a hard seal is formed between the valve seat and the ball. Low-temperature resistant sealing packing is disposed between the valve seat and the valve body. This ultra-low temperature metal hard-seal floating ball valve seat structure provides two seals between the valve seat and the valve body: a hard seal and a Lipseal packing, effectively preventing leakage between the valve seat and the valve body and ensuring a sealing effect under low-temperature conditions. Furthermore, the valve seat and valve body are separated into two parts, making it easier to perform fitting and adjustment between the valve seat and the ball.

[0003] In practical applications, existing technologies like the one described above have shortcomings: the main structure of the valve is made of metal, and the thermal expansion and contraction effect is obvious in ultra-low temperature environments. Gaps may appear between the sealing packing and the valve seat, between the sealing packing and the valve body, and even within the sealing packing itself, leading to sealing failure. Summary of the Invention

[0004] To address the above problems, this invention provides a valve sealing structure that effectively eliminates the gap between the valve body and the sealing element, ensuring a good sealing effect. This invention also provides a cryogenic ball valve incorporating this valve sealing structure.

[0005] To achieve the first objective of the invention, this utility model adopts the following technical solution: A valve sealing structure, comprising a valve seat and a valve body, which cooperate to form a sealing element mounting area. The sealing installation area is U-shaped, and a flexible sealing element is fitted into it; A support ring is installed at the U-shaped opening. The front end of the support ring abuts against the seal, causing the seal to deform to both sides of the U-shape.

[0006] Preferably, the sealing element is a lip seal; the opening of the lip seal faces the U-shaped opening; the front end of the support ring is inserted between the two lips of the lip seal, so that the two lips of the lip seal abut against the two side walls of the U-shape respectively.

[0007] Preferably, the support ring is slidable within the seal mounting area.

[0008] Preferably, the lip seal includes a seal body, which includes two lips, with a seal spring sandwiched between the lips; the seal spring has a hollow annular cross-sectional shape; the front end of the support ring abuts against the seal spring, causing the seal spring to deform towards both sides of the U-shape of the sealing installation area.

[0009] Preferably, the sealing ring spring has an elliptical ring cross-section, with the major radius of the ellipse pointing in the direction of insertion of the support ring in the relaxed state.

[0010] Preferably, a support ring pressure ring is also included, which is press-fitted onto the outside of the support ring.

[0011] Preferably, it also includes a compression spring with its elastic direction parallel to the insertion direction of the support ring; one end of the compression spring abuts against the fixing point, and the other end abuts against the support ring compression ring.

[0012] Preferably, the compression spring is a wave spring.

[0013] To achieve the second objective of the invention, the present invention adopts the following technical solution: A cryogenic ball valve employs the valve sealing structure described above.

[0014] The beneficial effects of this plan are: 1. A lip seal is used, which can effectively cope with the dimensional shrinkage of metal parts; 2. A support ring is inserted between the two lips of the lip-shaped sealing ring to prevent the lips from retracting; 3. The support ring abuts against the sealing ring spring, causing radial deformation, resulting in a more reliable sealing effect; 4. The pressure ring spring works in conjunction with the support ring pressure ring to prevent the support ring from retracting. Attached Figure Description

[0015] Figure 1 This is a schematic cross-sectional view of a valve sealing structure according to this utility model; Figure 2 yes Figure 1 This utility model provides a schematic cross-sectional view of the structure of an ultra-low temperature ball valve, which also serves as... Figure 1 Enlarged view of part I.

[0016] Among them: valve body 01, ball 02, valve cover 03, valve seat 04, valve stem 05, stuffing box 06, lower cover 07, lip seal 08, seal ring body 081, seal ring spring 082, support ring 09, support ring pressure ring 10, and pressure ring spring 11. Detailed Implementation

[0017] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0018] Example 1 Example 1 focuses on an innovative valve sealing structure design. For example... Figure 1 As shown, in ball valves or similar valve systems, the valve seat 04 and valve body 01 are typically configured as core components to achieve the normal function of the valve. The valve sealing structure proposed in this embodiment focuses on improving the sealing performance of the joint between the valve seat 04 and the valve body 01, constituting a key technological breakthrough.

[0019] Of particular note is that in the technical concept of this solution, the valve body 01 and valve cover 03 follow the same or similar structural principles when sealing with the valve seat 04, thus giving this solution broad applicability and versatility. For simplicity, this embodiment only selects the sealing fit structure between the valve cover 03 and the valve seat 04 as the demonstration object. If this solution needs to be extended to the sealing fit between the valve body 01 and the valve seat 04, simply replace the valve cover 03 in the embodiment with the valve body 01 to achieve a smooth transfer of technical effect, which is simple to operate and reliable.

[0020] Specific observations Figure 2 The valve seat 04 is designed as a lower structure, with a stepped shape that is higher on the left and lower on the right. This design helps to achieve more precise sealing positioning and higher sealing reliability. The valve cover 03 has an L-shaped layout, cleverly forming a tight fit with the valve seat 04, and is located above and to the right of it. Because the horizontal part on the top of the valve cover 03 fits tightly with the higher step on the left side of the stepped shape of the valve seat 04, a U-shaped sealing element installation area with an opening to the right is naturally formed between the horizontal part on the top of the valve cover 03 and the lower step on the right side of the stepped shape of the valve seat 04. This area is specifically designed for installing sealing elements to ensure the sealing performance of the valve under harsh conditions such as high pressure and low temperature.

[0021] In comparing and analyzing traditional solutions, we found that the cryogenic sealing packing used in products such as CN217056411U, due to the physical properties of thermal expansion and contraction of materials, may develop minute gaps between the sealing packing and valve seat 04, between the sealing packing and valve cover 03, and even within the sealing packing itself, under cryogenic operating conditions. These gaps significantly reduce the valve's sealing effect and may even lead to leakage accidents. To solve this problem, this solution features an innovative design improvement for the sealing element, selecting a sealing ring material with excellent elasticity, such as PTFE (polytetrafluoroethylene). These materials can be flexibly selected and applied according to the actual needs of those skilled in the art. The sealing ring is manufactured using a one-piece molding process, ensuring that it will not become loose or degrade in performance due to shrinkage under low-temperature conditions, thus effectively avoiding leakage problems caused by the sealing ring itself.

[0022] Furthermore, this embodiment also features a support ring 09 carefully fitted at the opening of the sealing element installation area. The support ring 09 has a T-shaped cross-section to perfectly fit the opening structure of the sealing element installation area. Overall, the support ring 09 can be securely installed within the opening of the sealing element installation area, with the vertical side of the T-shape serving as the leftward-extending front end and the horizontal side serving as the vertical rear end. The entire support ring 09 can slide freely left and right within the opening of the sealing element installation area to achieve precise pushing and deformation control of the sealing ring. By pushing the support ring 09 to the left, its front end generates a leftward pushing force on the sealing ring. This force causes the sealing ring to expand and deform in the left, up, and down directions, thereby further increasing the contact area and friction between the sealing ring and the valve seat 04 and valve cover 03, significantly improving the valve's sealing effect and reliability. Crucially, even in extreme low-temperature environments, the continuous and reliable pushing force of the support ring 09 ensures that the deformation of the sealing ring is sufficient to offset its own shrinkage due to cold. Furthermore, it has enough capacity to compensate for the increased clearance in the sealing area caused by the shrinkage of the valve seat 04 and valve cover 03 due to cold. Therefore, this solution ensures that the sealing area maintains excellent sealing performance and stability under various harsh operating conditions.

[0023] This embodiment serves as a fundamental application example of the solution, not only verifying the feasibility and effectiveness of the technical solution, but also laying a solid foundation for the technical evolution and optimization of subsequent embodiments.

[0024] Example 2 Based on inheriting and fully absorbing the core technology essence of Example 1, Example 2 has undergone systematic and effective optimization and upgrading, aiming to further improve the performance and reliability of the valve sealing structure.

[0025] The optimization measures in this embodiment are mainly reflected in the following two core aspects: Firstly, the selection of the sealing ring was refined and optimized, and the lip seal 08 was chosen as the preferred option. As a high-performance sealing element, the lip seal 08, with its unique structural design and excellent sealing characteristics, shows broad application prospects in the field of valve sealing.

[0026] Secondly, an innovative design was implemented for the fit between the support ring 09 and the lip seal 08. Specifically, the front end of the support ring 09 is carefully fitted and inserted between the upper and lower lips of the lip seal 08. This design allows the upper lip to tightly and continuously adhere upwards to the lower sealing surface of the valve cover 03 (i.e., the upper sidewall of the seal installation area), while the lower lip can also firmly adhere downwards to the upper sealing surface of the valve seat 04 (i.e., the lower sidewall of the seal installation area). This tight fit effectively ensures a high level of sealing performance of the seal installation area under various operating conditions.

[0027] The lip seal 08 features an ingenious structural design, comprising a seal body 081 with upper and lower lips extending cleverly to the right from the body. This structure's advantage stems from the thin and flexible nature of its lips, allowing for easier elastic deformation and a tighter fit with the sealing surface, forming an effective sealing barrier. However, it is worth noting that if the fit between the upper and lower lips and the sealing surface fails, the sealing effect will be severely affected, potentially leading to leakage.

[0028] To address this issue, this embodiment utilizes a support ring 09 that extends deep between the upper and lower lips of the lip seal 08, effectively preventing the risk of adhesion failure between the upper and lower lips and the sealing surface. To further enhance the support effect, the front end of the support ring 09 can be specifically shaped. For example, its end can be designed with a slightly enlarged shape to fully exert the compression effect on the upper and lower lips, enhancing the stability and durability of the seal. Of course, the specific shape improvement scheme should be flexibly adjusted and optimized by those skilled in the art based on actual working conditions and requirements to ensure the achievement of the best sealing effect.

[0029] Same as Example 1.

[0030] Example 3 Based on fully inheriting the technical advantages of Example 2, Example 3 has undergone more in-depth and refined evolution and optimization, aiming to further enhance the sealing performance of the valve sealing structure and its ability to adapt to complex working conditions.

[0031] The core optimization of this embodiment lies in the innovative installation of a sealing ring spring 082 between the upper and lower lips of the sealing ring body 081. The sealing ring spring 082 is typically made of metal to ensure sufficient strength and elastic recovery. Its overall design is a hollow annular structure, cleverly clamped to the outside of the sealing ring body 081, specifically located between the roots of the upper and lower lips, forming a stable support and elastic compensation mechanism.

[0032] In this structure, the role of the front end of the support ring 09 is further expanded and strengthened. It not only exerts a continuous compression effect on the upper and lower lips, ensuring a tight fit between the lips and the sealing surface, but also applies compression to the sealing ring spring 082. This dual compression mechanism allows the sealing ring spring 082 to deform precisely in the left, upper, and lower directions, thereby driving the sealing ring body 081 to deform synchronously in these three directions. This multi-directional deformation capability significantly enhances the sealing ring's fit and adaptability to the sealing surface, maintaining excellent sealing performance even when there are minor unevennesses on the sealing surface or changes in operating conditions.

[0033] To further optimize sealing performance, the cross-sectional shape of the sealing ring spring 082 is carefully designed in this embodiment. In the preferred embodiment, the cross-sectional shape of the sealing ring spring 082 is defined as an annular shape. The annular cross-section has isotropic characteristics. When one side is subjected to force, uniform elastic deformation is more likely to occur in the other three directions, thereby ensuring that the sealing ring spring 082 can maintain stable deformation characteristics under multi-directional compression, providing continuous and uniform elastic support for the sealing ring body 081.

[0034] Furthermore, to achieve a superior sealing effect, this embodiment proposes an even better cross-sectional shape design—an elliptical ring. The major diameter of the elliptical ring-shaped sealing spring 082 precisely coincides with the leftward pushing direction of the front end of the support ring 09. This design cleverly utilizes the geometric characteristics of an ellipse, allowing the sealing spring 082 to undergo greater elastic deformation in the major diameter direction when subjected to a leftward pushing force, thereby further amplifying the deformation effect after being pushed. This amplified deformation effect helps the sealing ring body 081 form a tighter and more comprehensive sealing contact, especially under extreme operating conditions or high-pressure environments, significantly improving the reliability and durability of the seal.

[0035] The shape of the front end of the support ring 09 can also be further adapted to the object being pushed.

[0036] Same as Example 2.

[0037] Example 4 Based on the technical context of the previous embodiments, Example 4 innovatively optimizes the positioning and force-bearing mechanism of the support ring 09, aiming to further improve the sealing stability and reliability of the lip seal ring 08.

[0038] In this embodiment, a composite structure of a support ring pressure ring 10 and a pressure ring spring 11 is carefully configured on the right side of the rear end of the support ring 09. The end dimensions of the support ring pressure ring 10 are precisely calculated to perfectly match the right opening dimensions of the U-shaped seal mounting area, ensuring smooth left-right sliding within the seal mounting area. In the assembled state, the support ring pressure ring 10 applies a stable counterforce to the rear end of the support ring 09 from right to left, effectively preventing the support ring 09 from loosening to the right due to vibration or external forces during operation, thereby providing a durable and reliable sealing guarantee for the lip seal ring 08.

[0039] The pressure ring spring 11, as a key component providing continuous elastic force, has its left end tightly pressed against the support ring pressure ring 10, while its right end rests against the right vertical side of the L-shaped structure of the valve cover 03, which is in a relatively fixed position. This layout design not only simplifies the installation process and improves assembly efficiency, but more importantly, it ensures that the pressure ring spring 11 can provide stable and continuous elastic force support for the support ring 09, maintaining stable sealing performance even under long-term valve operation or changing operating conditions.

[0040] From a theoretical perspective, omitting the support ring pressure ring 10 and directly pressing the left end of the pressure ring spring 11 against the rear end of the support ring 09 is technically feasible. However, in practical applications, due to the relatively small size of the rear end of the support ring 09 and the limited elastic contact surface of the pressure ring spring 11, precise alignment between the two is difficult, and uneven force transmission or failure can easily occur due to assembly deviations or minor displacements during operation. Therefore, this embodiment innovatively introduces the support ring pressure ring 10 as a force-bearing intermediate element, effectively solving this technical problem and improving the reliability and stability of the entire sealing structure.

[0041] Furthermore, to optimize the performance of the pressure ring spring 11, this embodiment preferably uses a wave spring as the specific form of the pressure ring spring 11. With its unique wave structure, the wave spring can provide a large reserve of elastic force within a limited axial space, while also possessing good fatigue life and impact resistance. This choice not only improves the elastic force output efficiency of the pressure ring spring 11 but also enhances the adaptability of the entire sealing structure to complex working conditions, providing a strong guarantee for the long-term stable operation of the valve.

[0042] It should be stated that this solution can be applied not only to the sealing structure of valve seat, valve body and elastic sealing ring, but also to similar sealing structures. By applying additional radial pressure to the elastic sealing ring, the elastic sealing ring is deformed in the radial direction, thereby improving the sealing effect.

[0043] Example 5 Example 5 is a cryogenic ball valve that uses the valve sealing structure as described in Example 4.

[0044] See Figure 1 As shown, the cryogenic ball valve in this embodiment is used in an LNG receiving station, and its working environment is a cryogenic environment.

[0045] The cryogenic ball valve of this embodiment includes a valve body 01 and a valve cover 03 assembled on the left and right. The assembly space contains a ball 02, and the lower cover 07 is located below the assembly space. A valve seat 04 is located between the valve body 01 or the valve cover 03 and the ball 02. The upper part of the ball 02 is connected to the valve stem 05, and the valve stem 05 is sleeved in the stuffing box 06.

[0046] In this embodiment, the valve sealing structure as shown in Embodiment 4 is applied between the valve body 01 and the valve seat 04, and between the valve cover 03 and the valve seat 04 of the cryogenic ball valve.

Claims

1. A valve sealing structure, comprising a valve seat (04) and a valve body (01), which cooperate to form a sealing element mounting area, characterized in that, The sealing installation area is U-shaped, and a flexible sealing element is fitted into it; A support ring (09) is installed at the U-shaped opening. The front end of the support ring (09) abuts against the seal, causing the seal to deform to both sides of the U-shape.

2. The valve sealing structure according to claim 1, characterized in that, The sealing element is a lip seal (08); the opening of the lip seal (08) faces the U-shaped opening; the front end of the support ring (09) is inserted between the two lips of the lip seal (08), so that the two lips of the lip seal (08) abut against the two side walls of the U-shape respectively.

3. A valve sealing structure according to claim 1 or 2, characterized in that, The support ring (09) can slide within the seal installation area.

4. The valve sealing structure according to claim 3, characterized in that, The lip seal (08) includes a seal body (081), the seal body (081) includes two lips, and a seal spring (082) is sandwiched between the two lips; the seal spring (082) has a hollow annular cross-section; the front end of the support ring (09) abuts against the seal spring (082), causing the seal spring (082) to deform towards both sides of the U-shape of the sealing installation area.

5. A valve sealing structure according to claim 4, characterized in that, The cross-sectional shape of the sealing ring spring (082) is an elliptical ring, and in the relaxed state, the direction of the major radius of the ellipse is the insertion direction of the support ring (09).

6. The valve sealing structure according to claim 4, characterized in that, It also includes a support ring pressure ring (10) that is press-fitted onto the outside of the support ring (09).

7. A valve sealing structure according to claim 6, characterized in that, It also includes a compression spring (11) whose elastic direction is parallel to the insertion direction of the support ring (09); one end of the compression spring (11) abuts against the fixed point, and the other end abuts against the support ring compression ring (10).

8. A valve sealing structure according to claim 7, characterized in that, The compression ring spring (11) is a wave spring.

9. A cryogenic ball valve, characterized in that, The valve sealing structure as described in claim 1 is applied.

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