Low-temperature two-way lip-shaped sealing floating ball valve

Abstract

The utility model relates to a low-temperature two-way lip-shaped sealing floating ball valve which comprises a valve body, a valve cover, a ball body, a valve seat, a valve rod, a support and a transmission mechanism, the valve seat is of a floating structure, the support is of a lengthened structure, and a heat insulation plate is arranged in the middle of the support. Composite sealing devices composed of sealing washers and pressure self-sealing devices are arranged between the valve body and the valve deck and between the valve body and the support respectively, medium pressure pushes wedge-caulking rings of the pressure self-sealing devices to open sealing between the two sides of elastic expanding and shrinking rings and the valve body, between the valve deck and the support and between the valve body and the support, and self-sealing between the valve body and the valve deck and between the valve body and the support is achieved. The problem that the sealing performance between the valve body and the valve cover and between the valve body and the support is reduced due to shrinkage of the sealing washer under the low-temperature working condition is solved, and zero leakage is achieved. The sealing device is reliable in sealing performance and suitable for working conditions of low-temperature media such as liquid nitrogen, liquid oxygen and liquefied natural gas.

Description

Technical Field

[0001] This utility model relates to a ball valve, and more particularly to a low-temperature bidirectional sealing floating ball valve. Background Technology

[0002] Floating ball valves are widely used in pipeline systems for transporting cryogenic and ultra-crescent media such as liquid oxygen, liquid nitrogen, and liquefied natural gas due to their simple structure, convenient opening and closing, and full-flow performance. Their structure generally includes a valve body, valve cover, valve seat, ball, valve stem, and transmission mechanism. To reduce the impact of cryogenic media on the transmission mechanism, the transmission mechanism is generally mounted on the upper end face of the valve body cavity via an extension rod. To prevent the valve seat from jamming due to thermal expansion and contraction, the valve seat generally adopts a floating structure. However, the main drawbacks of existing cryogenic ball valves are: dynamic sealing is generally achieved between the valve seat and valve body using a sealing ring, while static sealing is achieved between the valve body and valve cover, and between the extension bracket and valve body using sealing gaskets. These sealing rings and gaskets are prone to leakage during cryogenic contraction, resulting in poor sealing performance. Utility Model Content

[0003] This utility model addresses the shortcomings of existing technologies by providing a low-temperature bidirectional lip-sealed floating ball valve with reliable sealing performance, where the valve body, valve seat, valve cover, and extended support each have a self-sealing function based on medium pressure.

[0004] The technical solution for realizing this utility model is as follows:

[0005] A cryogenic bidirectional lip-sealed floating ball valve includes a valve body, a valve cover, a ball, a valve seat, a valve stem, a bracket, and a transmission mechanism. The valve seat adopts a floating structure, with a pressure ring and a disc spring installed within the radial step of the valve body and valve cover passage. The valve seat sealing surface and the ball surface form a bidirectional sealing structure. The ball is installed at the lower end of the valve stem and placed within the valve cavity to form a floating ball valve structure. The bracket adopts an extended structure with a heat insulation plate in the middle. The valve valve is characterized by having composite sealing devices installed between the valve body, valve cover, and bracket. The composite sealing device consists of a sealing gasket and a pressure self-sealing device. The pressure self-sealing device consists of an elastic expansion ring and a wedge ring, which are installed as a whole within a sealing cavity near the valve cavity. The elastic expansion ring has an annular expansion groove in the middle of one side of its annular plane, and the wedge ring is embedded in the annular expansion groove. The opening of the annular expansion groove faces the valve cavity.

[0006] A preferred embodiment is to provide one-way sealing devices between the outer surface of the valve seat and the inner wall of the valve body and valve cover passage. The one-way sealing device consists of a lip sealing ring, an elastic hollow ring, a tightening ring, and an annular disc spring. The lip sealing ring has a U-shaped groove, with the opening of the U-shaped groove facing away from the valve cavity. The elastic hollow ring is embedded in the U-shaped groove. One side of the tightening ring has an annular protrusion that contacts the elastic hollow ring. The annular disc spring is installed between the tightening ring and the pressure ring on the other side. The outer surface of the tightening ring is clearance-fitted with the inner wall of the valve body and valve cover passage.

[0007] The preferred embodiment is that the annular expansion groove is a U-shaped groove, and the wedge-tightening ring is an elastic hollow ring with a circular cross-section.

[0008] The preferred embodiment is that the annular expansion groove is a V-shaped groove, the wedge ring is a circular ring with a triangular cross-section, and there is a triangular cavity between the bottom of the annular expansion groove and the wedge ring.

[0009] The advantages of this utility model compared with the prior art are:

[0010] 1. A composite sealing device consisting of a sealing gasket and a pressure self-sealing device is installed between the valve body, the valve cover, and the bracket. The medium pressure pushes the wedge ring to open the elastic expansion ring on both sides and the seal between the valve body, the valve cover, and the bracket, thereby achieving self-sealing between the valve body, the valve cover, and the bracket. This solves the problem of reduced sealing performance between the valve body and the valve cover and between the valve body and the bracket due to the shrinkage of the sealing gasket under low temperature conditions, achieving zero external leakage.

[0011] 2. One-way sealing devices are installed between the outer surface of the valve seat and the inner wall of the valve body and valve cover channels. The pressure of the medium flowing in from the valve body or valve cover channel pushes the lip seal ring to open the seal, realizing the self-sealing between the valve seat and the valve body and valve cover. Abnormal high pressure in the valve cavity will compress the lip seal ring radially, so that the pressure in the valve cavity is released through the outer ring surface of the lip seal ring and the inner wall of the flow channel of the valve body or valve cover, preventing the medium in the valve cavity from generating abnormal high pressure due to temperature changes, which could lead to safety accidents. This constitutes a one-way sealing function between the valve seat and the valve body channel and the valve cover channel. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model.

[0013] Figure 2 This is a utility model Figure 1 Enlarged view of the local structure at point A in the middle.

[0014] Figure 3 This is a utility model Figure 1 Enlarged view of the local structure at point B in the middle.

[0015] Figure 4 This is a utility model Figure 1Enlarged view of the local structure at point C.

[0016] In the diagram: 1 Valve body, 2 Valve cover, 3 Ball, 4 Valve seat, 5 Pressure ring, 6 Disc spring, 7 Bracket, 8 Valve stem, 9 Heat insulation plate, 10 Packing seal device, 11 Lip seal ring, 12 Elastic hollow ring, 13 Tightening ring, 14 Annular disc spring, 15 Sealing gasket, 16 First elastic expansion ring, 17 First wedge ring, 18 Second elastic expansion ring, 19 Second wedge ring. Detailed Implementation

[0017] like Figure 1 The low-temperature bidirectional lip-sealed floating ball valve shown includes a valve body 1, a valve cover 2, a ball 3, a valve seat 4, a valve stem 8, a bracket 7, and a transmission mechanism. The valve seat 4 adopts a floating structure and is installed in the radial steps of the valve body 1 and valve cover 2 channels by a pressure ring 5 and a disc spring 6. That is, the valve seat 4 is installed in the valve body 1 channel and the valve cover 2 channel respectively, forming a bidirectional sealing structure. The ball 3 is installed at the lower end of the valve stem 8 and placed in the valve cavity to form a floating ball structure. The bracket 7 adopts an extended structure and a heat insulation plate 9 is set in the middle to reduce the influence of the low-temperature medium on the packing seal device 10 and the transmission mechanism. Sealing gaskets 15 are respectively set in the contact plane between the valve body 1, the valve cover 2, and the bracket 7 to respectively realize the sealing of the valve body. A static seal is provided between valve body 1 and valve cover 2, and between valve body 1 and bracket 7; characterized in that: pressure self-sealing devices are respectively provided between valve body 1 and valve cover 2, and between valve body 1 and bracket 7, the pressure self-sealing devices and sealing gasket 15 forming a composite sealing structure; the pressure self-sealing device between valve body 1 and valve cover 2 is composed of a first elastic expansion ring 16 and a first wedge ring 17, which are installed as a whole in the sealing cavity between the contact planes of valve body 1 and valve cover 2, the first elastic expansion ring 16 has an annular expansion groove in the middle of one side of the annular plane, the first wedge ring 17 is embedded in the annular expansion groove, and the opening of the annular expansion groove is installed in the direction of medium flowing into the sealing cavity between valve body 1 and valve cover 2, such as Figure 3 As shown, when the medium enters the sealing cavity between the valve body 1 and the valve cover 2, the medium pressure pushes the first wedge ring 17, expands the first elastic expansion ring 16, and presses it to seal the valve body 1 and the valve cover 2, realizing the pressure self-sealing between the valve body 1 and the valve cover 2. This solves the problem of leakage caused by the long-term low-temperature shrinkage of the sealing gasket 15 between the valve body 1 and the valve cover 2, resulting in a decrease in sealing performance. The pressure self-sealing device between the valve body 1 and the bracket 7 is composed of a second elastic expansion ring 18 and a second wedge ring 19, which are installed as a whole in the sealing cavity between the valve body 1 and the bracket 7. The second elastic expansion ring 18 has an annular expansion groove in the middle of one side of its annular plane, and the second wedge ring 19 is embedded in the annular expansion groove. The opening of the annular expansion groove faces the direction of the medium flowing into the sealing cavity between the valve body 1 and the bracket 7. Figure 4As shown, when the medium enters the sealing cavity between the valve body 1 and the bracket 7, the medium pressure pushes the second wedge ring 19, expands the second elastic compression ring 18, and presses it to seal the valve body 1 and the bracket 7, realizing the pressure self-sealing between the valve body 1 and the bracket 7. This solves the problem of leakage caused by the long-term low-temperature shrinkage of the sealing gasket 15 between the valve body 1 and the bracket 7, which leads to a decrease in sealing performance.

[0018] One-way sealing devices are respectively installed between the outer circular surface of the valve seat 4 and the inner wall of the valve body 1 and valve cover 2 passage. Each one-way sealing device consists of a lip-shaped sealing ring 11, an elastic hollow ring 12, a tightening ring 13, and an annular disc spring 14. The lip-shaped sealing ring 11 has a U-shaped groove, with the opening of the U-shaped groove facing away from the valve cavity. The elastic hollow ring 12 is embedded in the U-shaped groove. One side of the tightening ring 13 has an annular protrusion that contacts the elastic hollow ring 12. The annular disc spring 14 is installed between the other side of the tightening ring 13 and the pressure ring 5. Figure 2 As shown, when the ball 3 is closed, the pressure of the inlet medium pushes the tightening ring 13 and the elastic hollow ring 12 of the one-way sealing device on the inlet side, wedging them into the U-shaped groove and opening the lip sealing ring 11 to achieve a seal between the outer surface of the valve seat 4 and the inner wall of the channel. The abnormal high pressure in the valve cavity pushes the tightening ring 13 and the elastic hollow ring 12 out of the U-shaped groove, compressing the lip sealing ring 11 to release the abnormal high pressure in the valve cavity and protect the valve safety. The outer surface of the tightening ring 13 is fitted with the inner wall of the valve body 1 and the valve cover 2 channel to ensure the release of valve cavity pressure.

[0019] The annular expansion groove adopts a U-shaped groove, and the first wedge ring 17 and the second wedge ring 19 adopt elastic hollow rings with circular cross-sections to improve their elastic deformation performance.

[0020] The annular expansion groove adopts a V-shaped groove, and the first wedge ring 17 and the second wedge ring 19 adopt a triangular cross-section ring. There is a triangular cavity between the bottom of the V-shaped groove and the first wedge ring 17 and the second wedge ring 19, which ensures that the first wedge ring 17 and the second wedge ring 19 can be embedded in the V-shaped groove when pushed by the medium pressure, and reliably expand the first elastic expansion ring 16 and the second elastic expansion ring 18.

Claims

1. A low-temperature bidirectional lip-sealed floating ball valve, comprising a valve body (1), a valve cover (2), a ball (3), a valve seat (4), a valve stem (8), a bracket (7), and a transmission mechanism, wherein the valve seat (4) adopts a floating structure and is installed in the radial step of the valve body (1) and valve cover (2) channel by a pressure ring (5) and a disc spring (6) to form a bidirectional sealing structure; the ball (3) is installed at the lower end of the valve stem (8) and placed in the valve cavity to form a floating ball structure; the bracket (7) adopts an extended structure and a heat insulation plate (9) is provided in the middle; and sealing gaskets (15) are respectively provided in the contact plane between the valve body (1), the valve cover (2), and the bracket (7); its characteristic is: Pressure self-sealing devices are respectively provided between the valve body (1) and the valve cover (2) and between the valve body (1) and the bracket (7). The pressure self-sealing device and the sealing gasket (15) form a composite sealing structure. The pressure self-sealing device between the valve body (1) and the valve cover (2) is composed of a first elastic expansion ring (16) and a first wedge ring (17), which are installed as a whole in the sealing cavity between the contact planes of the valve body (1) and the valve cover (2). The first elastic expansion ring (16) has an annular expansion groove in the middle of one side of the annular plane, and the first wedge ring (17) is embedded in the annular expansion groove. The annular expansion groove is installed with the medium flowing into the sealing cavity between the valve body (1) and the valve cover (2). The pressure self-sealing device between the valve body (1) and the bracket (7) consists of a second elastic expansion ring (18) and a second wedge ring (19), which are installed as a whole in the sealing cavity between the valve body (1) and the bracket (7). The second elastic expansion ring (18) has an annular expansion groove in the middle of one side of the annular plane, and the second wedge ring (19) is embedded in the annular expansion groove. The opening of the annular expansion groove is installed with the medium flowing into the sealing cavity between the valve body (1) and the bracket (7).

2. The cryogenic bidirectional lip-sealed floating ball valve according to claim 1, characterized in that: One-way sealing devices are respectively provided between the outer circular surface of the valve seat (4) and the inner wall of the valve body (1) and valve cover (2) channel. The one-way sealing device consists of a lip sealing ring (11), an elastic hollow ring (12), a tightening ring (13), and an annular disc spring (14). The lip sealing ring (11) has a U-shaped groove, and the opening of the U-shaped groove is installed away from the valve cavity direction. The elastic hollow ring (12) is embedded in the U-shaped groove. An annular convex ring is provided on one side of the tightening ring (13), and the annular convex ring contacts the elastic hollow ring (12). The annular disc spring (14) is installed between the other side of the tightening ring (13) and the pressure ring (5). The outer circular surface of the tightening ring (13) is clearance-fitted with the inner wall of the valve body (1) and valve cover (2) channel.

3. The cryogenic bidirectional lip-sealed floating ball valve according to claim 1 or 2, characterized in that: The annular expansion groove adopts a U-shaped groove, and the first wedge ring (17) and the second wedge ring (19) adopt an elastic hollow ring with a circular cross section.

4. The cryogenic bidirectional lip-sealed floating ball valve according to claim 1 or 2, characterized in that: The annular expansion groove adopts a V-shaped groove, and the first wedge ring (17) and the second wedge ring (19) adopt a triangular cross-section ring. There is a triangular cavity between the bottom of the V-shaped groove and the first wedge ring (17) and the second wedge ring (19).

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