Ultra-low temperature top-entry ball valve with valve seat seal structure

Abstract

This utility model discloses an ultra-low temperature top-mounted ball valve with a valve seat sealing structure, relating to the field of valve equipment technology. It includes a valve body and a ball disposed within the valve body's internal cavity. The valve body has an inlet and an outlet end, respectively. Both the inlet and outlet ends of the valve body are equipped with valve seat support rings. A valve seat is disposed between the valve seat support ring and the ball, with the valve seat support ring pressing the valve seat against the ball surface to form a sealing fit. An annular support ring groove is coaxially provided on the side of the valve seat support ring closest to the ball, and the valve seat is embedded in the support ring groove with an interference fit. A stepped surface is provided on the side of the valve seat located within the support ring groove, and a sealing ring is fitted onto the stepped surface. The width of the stepped surface is greater than the width of the sealing ring. The sealing ring can move axially under the pressure of the medium, thereby sealing any gaps created, improving sealing performance, and preventing leakage at the mating part between the valve seat and the valve seat support ring.

Description

Technical Field

[0001] This utility model relates to the field of valve equipment technology, and in particular to an ultra-low temperature top-mounted ball valve with a valve seat sealing structure. Background Technology

[0002] When a cryogenic top-mounted ball valve is closed, the pressure of the medium trapped in the valve body cavity increases with rising temperature. To achieve automatic pressure relief, existing cryogenic top-mounted ball valves typically have a one-way seal at the inlet and a two-way seal at the outlet. Cryogenic top-mounted ball valves are susceptible to internal leakage at low temperatures. The main causes of internal leakage include: 1. Leakage between the valve seat sealing surface and the ball; 2. Leakage at the mating point between the valve seat support ring and the valve body; 3. Leakage at the mating point between the valve seat and the valve seat support ring. Causes 1 and 2 have been addressed. For cause 3, the current main solution is to press the pre-machined valve seat into the valve seat support ring at low temperatures using an interference fit. However, there are uncertainties in controlling the pressing temperature and the interference fit. Because the valve seat and valve seat support ring are made of different materials, their shrinkage rates differ significantly at low temperatures, making it difficult to guarantee the sealing performance of the valve seat and valve seat support ring under these conditions. Therefore, leakage still exists between the valve seat and valve seat support ring in actual operation.

[0003] Chinese utility model patent document CN212297700U discloses a sealing device for a cryogenic ball valve. The technical solution includes a valve body, a metal valve seat, and a ball. An annular metal support ring and an annular first lip seal are installed in the space between the valve body and the metal valve seat. The first lip seal includes two first lips with an annular groove between them. The outer side of the first lip seal abuts against the valve body, and the inner side abuts against the metal valve seat. One end of the metal support ring is a protruding head, and the other end is a set of circular holes. The protruding head abuts against the annular groove of the first lip seal. A thrust spring is installed inside the circular holes of the metal support ring, and the other end of the thrust spring abuts against the valve body. Although the technical solution of this utility model can improve the sealing performance between the valve body and the valve seat, as well as between the valve seat and the ball, it is necessary to add a thrust spring, a support ring, and a sealing ring between the valve body and the valve seat. The thrust spring provides elastic force to squeeze the support ring and the sealing ring to improve the sealing performance, and there is still room for optimization in the structure. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an ultra-low temperature top-mounted ball valve with a valve seat sealing structure that has a simple structure and can effectively improve the sealing effect between the valve seat and the valve seat support ring.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: an ultra-low temperature top-mounted ball valve with a valve seat sealing structure, including a valve body and a ball disposed in the inner cavity of the valve body. The two ends of the valve body are the inlet end and the outlet end, respectively. Both the inlet end and the outlet end of the valve body are provided with valve seat support rings. A valve seat is provided between the valve seat support ring and the ball. The valve seat support ring presses the valve seat tightly against the surface of the ball to form a sealing fit. The valve seat support ring is coaxially provided with an annular support ring groove on the side near the ball. The valve seat is embedded in the support ring groove and is interference-fitted with the support ring groove. A stepped surface is provided on the side of the valve seat located in the support ring groove. A sealing ring is fitted on the stepped surface. The width of the stepped surface is greater than the width of the sealing ring.

[0006] As an improvement to the above solution: the sealing ring is a lip seal, with the lip of the lip seal facing the bottom of the support ring groove.

[0007] As an improvement to the above solution, an elastic support ring is also included. The elastic support ring is an annular support ring that is fixed inside the lip opening of the sealing ring and is coaxially arranged with the sealing ring. Both sides of the elastic support ring are bent toward the valve seat support ring to form a U-shaped opening with the same orientation as the lip opening of the sealing ring.

[0008] As an improvement to the above solution: the edge of the lip opening of the sealing ring is provided with an inwardly bent limiting stop, which is overturned onto the edge of the U-shaped opening of the elastic support ring to form a limiting fit.

[0009] As an improvement to the above solution: the two sides of the U-shaped opening formed by the elastic support ring are radially outward-expanding oblique sides.

[0010] As an improvement to the above solution: the valve seat is provided with at least one degassing groove, which is located on the outer side of the valve seat.

[0011] As an improvement to the above solution: the width difference between the stepped surface and the sealing ring is ≥2mm.

[0012] The beneficial effects of this utility model are as follows: This utility model improves the sealing structure between the valve seat and the valve seat support ring in an ultra-low temperature top-mounted ball valve. By setting a support ring groove on the valve seat support ring to allow the valve seat to be embedded to form an interference fit, and setting a stepped surface on the valve seat to form a space with the support ring groove to accommodate the sealing ring, a gap will be generated between the mating surfaces of the valve seat and the support ring groove due to the different shrinkage rates of the materials under low temperature working conditions. The medium flowing in the valve can enter the support ring groove through the gap. Because there is a width difference between the stepped surface of the valve seat and the sealing ring, the sealing ring can move axially under the push of the medium pressure, thereby sealing the gap and improving the sealing performance, preventing leakage at the mating part of the valve seat and the valve seat support ring. Attached Figure Description

[0013] Figure 1 This is a cross-sectional view of the structure of this utility model;

[0014] Figure 2 This is a schematic diagram of the initial state of the sealing ring after the valve seat is pressed into the valve seat support ring in this utility model.

[0015] Figure 3 This is a schematic diagram showing the state of the sealing ring after the valve seat is compressed in this utility model;

[0016] Figure 4 This is an isometric view of the valve seat structure.

[0017] The markings in the diagram are: 100-valve body, 200-ball, 300-valve seat support ring, 310-support ring groove, 400-valve seat, 410-step surface, 420-degassing groove, 500-sealing ring, 510-elastic support ring. Detailed Implementation

[0018] To facilitate understanding of this utility model, the following description, in conjunction with the accompanying drawings, will provide further details.

[0019] In the description of this utility model, it should be noted that the terms "front", "rear", "left", "right", "up", "down", "inner", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of description and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] like Figures 1 to 3 As shown, the cryogenic top-mounted ball valve with a valve seat sealing structure disclosed in this utility model includes a valve body 100, a ball 200, a valve seat support ring 300, and a valve seat 400. The valve body 100 has an inlet end and an outlet end, both of which communicate with the internal cavity of the valve body 100. The ball 200 is disposed within the internal cavity of the valve body 100, and the flow of the medium is controlled by the lifting and rotation of the ball 200. A valve seat support ring 300 is provided at both the inlet and outlet ends of the valve body 100. A valve seat 400 is positioned between the valve seat support ring 300 and the ball 200, pressing the valve seat 400 against the surface of the ball 200 to form a sealing fit.

[0021] This utility model improves the mating structure of the valve seat support ring 300 and the valve seat 400, such as... Figure 2 and Figure 3As shown, an annular support groove 310 is provided on the side of the valve seat support ring 300 near the ball 200. The support groove 310 is coaxial with the valve seat support ring 300, and the shape and size of the support groove 310 are adapted to the valve seat 400 so that the valve seat 400 can be embedded in the support groove 310 to form an interference fit; at the same time, as Figure 4 As shown, a step is provided at the end of the valve seat 400 that mates with the valve seat support ring 300, so that the side of the valve seat 400 located in the support ring groove 310 forms a stepped surface 410. A sealing ring 500 is fitted onto the stepped surface 410, and the axial width of the sealing ring 400 is limited to be less than the axial width of the stepped surface 410, so that the sealing ring 500 has a path for translation after being fitted onto the stepped surface 410. Figure 2 As shown, when the valve seat 400 with the sealing ring 500 is embedded in the support ring groove 310 on the valve seat support ring 300, there is a gap H between the sealing ring 500 and the stepped end face of the valve seat 400. This gap H is the width difference between the sealing ring 500 and the valve seat 400, and the size of the gap H is ≥2mm. When the cryogenic top-mounted ball valve is in a cryogenic working state, under the action of the cryogenic medium, a gap is generated between the mating surfaces of the valve seat 400 and the valve seat support ring 300 due to the difference in shrinkage rate of their different materials. At this time, if... Figure 3 As shown, the medium inside the valve body 100 can flow into the support ring groove 310 of the valve seat support ring 300 along the direction of the arrow shown in the figure. Then, the sealing ring 500 can be axially translated towards the stepped end face of the valve seat 400 under the push of the medium pressure. At this time, the size of the gap H becomes 0, thereby achieving sealing of the mating part between the valve seat support ring 300 and the valve seat 400 without the need for components such as thrust springs in the prior art. In addition, as Figure 4 As shown, at least one degassing groove 420 can also be provided on the outer side of the valve seat 400. The degassing groove 420 is located on the part of the valve seat 400 where the step surface 410 is not provided. By providing the degassing groove 420 on the valve seat 400, the space in the support ring groove 310 between the sealing ring 500 and the step end face is connected to the inside of the valve body 100. During the translation of the sealing ring 500, the size of the spacing H decreases. At this time, the gas in this space can be discharged from the support ring groove 310 through the degassing groove 420, so as to avoid the internal air pressure from generating resistance to the translation of the sealing ring 500 and affecting the translation of the sealing ring 500.

[0022] Furthermore, such as Figure 2 and Figure 3 As shown, the sealing ring 500 in this utility model adopts a lip seal ring, and the lip opening of the lip seal ring is limited to facing the bottom of the support ring groove 310. When the medium enters the support ring groove 310, it will apply pressure to the lip seal ring through the lip opening, thereby increasing the contact area between the medium and the lip seal ring and improving the pressure effect of the medium on the lip seal ring.

[0023] Furthermore, such as Figure 2 and Figure 3 As shown, this utility model also provides an elastic support ring 510 inside the sealing ring 500. The elastic support ring 510 is an annular support ring fixed inside the lip opening of the sealing ring 500 and coaxially arranged with the sealing ring 500. Both sides of the elastic support ring 510 are bent towards the valve seat support ring 300 to form a U-shaped opening with the same orientation as the lip opening of the sealing ring 500, that is, the cross-section of the elastic support ring 510 is U-shaped. Furthermore, the two sides of the elastic support ring 510 forming the U-shaped opening can be further defined as radially outwardly expanding inclined sides, that is, the cross-section of the elastic support ring 510 is V-shaped, so that the U-shaped opening of the elastic support ring presents an outwardly expanding opening. This invention uses an elastic support ring 510 to support the sealing ring 500. During the installation process of fitting the sealing ring 500 onto the valve seat 400 and embedding the valve seat 400 into the support ring groove 310, the elastic support ring 510 can be compressed to produce elastic deformation. After the valve seat 400 is embedded in the support ring groove 310, the elastic support ring 510 can press the sealing ring 500 onto the mating surface through its own elastic force to recover its deformation, thereby further improving the sealing effect of the sealing ring 500.

[0024] Furthermore, such as Figure 2 and Figure 3 As shown, in order to improve the overall stability of the sealing ring 500 and the elastic support ring 510, the present invention can also provide an inwardly bent limiting edge at the edge of the lip opening of the sealing ring 500. The limiting edge is overturned onto the edge of the U-shaped opening of the elastic support ring 510 to form a limiting fit, so as to prevent the elastic support ring 510 from detaching from the lip opening of the sealing ring 500.

[0025] When assembling the cryogenic top-mounted ball valve with a valve seat sealing structure disclosed in this utility model, first clean the valve seat support ring 300 with a metal cleaner and let it air dry. Then soak it in alcohol for at least 15 minutes and let it air dry. Clean the support ring groove 310 of the valve seat support ring 300 with acetone. After it is completely dry, use a 365nm ultraviolet flashlight to check the degreased surface of the support ring groove 310. If there is no bright blue fluorescence, it is considered qualified. Soak the processed valve seat 400 in alcohol for at least 15 minutes and let it air dry. Then wipe all surfaces of the valve seat 400 with a lint-free cloth soaked in carbon tetrachloride. Figure 2 As shown, the valve seat 400 is press-fitted into the support ring groove 310 of the valve seat support ring 300 using a press. After holding the pressure for 10 minutes, it is removed and the sealing surface between the valve seat 400 and the ball 200 is machined according to the design dimensions.

[0026] like Figure 3As shown, when the assembled cryogenic top-mounted ball valve is in operation, under the action of the cryogenic medium, the valve seat 400 and the valve seat support ring 300 contract. Due to the different shrinkage rates of the materials of the valve seat 400 and the valve seat support ring 300, gaps will be generated on the three surfaces of the valve seat 400 that contact the support ring groove 310 in the valve seat support ring 300. The medium will enter the support ring groove 310, and the sealing ring 500 will undergo axial translation under the action of the medium pressure. Furthermore, due to the medium pressure, the elastic support ring 510 will open at a larger angle, causing the two sides of the sealing ring 500 to fit tightly against the support ring groove 310, thereby producing a better sealing effect and preventing medium leakage.

[0027] The cryogenic top-mounted ball valve with a valve seat sealing structure disclosed in this utility model can ensure a stable sealing effect at the mating part of the valve seat 400 and the valve seat support ring 300, effectively preventing media leakage; at the same time, it is not limited to pressing the valve seat 400 into the valve seat support ring 300 only at low temperature, but can also complete the assembly of the valve seat 400 and the valve seat support ring 300 even at normal temperature.

Claims

1. A cryogenic top-mounted ball valve with a valve seat sealing structure, comprising a valve body (100) and a ball (200) disposed in the inner cavity of the valve body (100), wherein the two ends of the valve body (100) are an inlet end and an outlet end, respectively, and both the inlet end and the outlet end of the valve body (100) are provided with valve seat support rings (300), and a valve seat (400) is provided between the valve seat support ring (300) and the ball (200), wherein the valve seat support ring (300) presses the valve seat (400) tightly against the surface of the ball (200) to form a sealing fit, characterized in that: The valve seat support ring (300) has an annular support ring groove (310) coaxially arranged on the side near the ball (200). The valve seat (400) is embedded in the support ring groove (310) and is press-fitted with the support ring groove (310). The valve seat (400) has a stepped surface (410) on the side of the valve seat (400) located in the support ring groove (310). A sealing ring (500) is fitted on the stepped surface (410). The width of the stepped surface (410) is greater than the width of the sealing ring (500).

2. The ultra-low temperature top-entry ball valve with seat seal structure of claim 1, wherein: The sealing ring (500) is a lip seal, with the lip facing the bottom of the support ring groove (310).

3. The ultra-low temperature top-entry ball valve with seat seal structure of claim 2, wherein: It also includes an elastic support ring (510), which is an annular support ring fixed inside the lip opening of the sealing ring (500) and coaxially arranged with the sealing ring (500); both sides of the elastic support ring (510) are bent toward the valve seat support ring (300) to form a U-shaped opening with the same orientation as the lip opening of the sealing ring (500).

4. The ultra-low temperature top-entry ball valve with seat seal structure of claim 3, wherein: The edge of the lip opening of the sealing ring (500) is provided with an inwardly bent limiting stop, which is overturned onto the edge of the U-shaped opening of the elastic support ring (510) to form a limiting fit.

5. The ultra-low temperature top-entry ball valve with seat seal structure of claim 3, wherein: The elastic support ring (510) forms a U-shaped opening with radially outward-expanding oblique sides on both sides.

6. The ultra-low temperature top-entry ball valve with seat seal structure of claim 1, wherein: The valve seat (400) is provided with at least one degassing groove (420), which is located on the outer side of the valve seat (400).

7. The ultra-low temperature top-entry ball valve with seat seal structure of claim 1, wherein: The width difference between the stepped surface (410) and the sealing ring (500) is ≥2mm.

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