Ultrahigh pressure valve rod sealing element

Abstract

The utility model relates to the technical field of valve rod sealing, and discloses an ultrahigh pressure valve rod sealing element which comprises a sealing ring and a supporting ring arranged at the root of the sealing ring, the sealing ring comprises a base body and a sealing lip, the sealing lip is arranged at the top, away from the supporting ring, of the base body, and a lip edge is formed on the outer side of the sealing lip. The lip edge is of a single-layer structure in the direction from the top of the sealing ring to the root of the sealing ring and is provided with a curved surface protruding outwards, and the curved surface is in smooth connection with the outer wall of the base body. Only the single-layer lip edge is arranged on the outer side of the sealing lip, the number of the lip edges is reduced, the radial interval is formed between the curved surface of the lip edge and the outer wall of the base body, after the sealing lip is subjected to the working conditions of ultrahigh pressure and high and low temperature, generated abrasion chippings can be discharged from the bottom of the lip edge, chipping accumulation can be prevented, and then the risk of sealing failure is greatly reduced; as the service time is prolonged and the friction loss is caused, the section of the sealing lip is thinned, and the curved surface of the lip edge protrudes outwards, so that the thickness of the sealing lip is increased, and the service life of a product is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of valve stem sealing technology, and in particular to an ultra-high pressure valve stem seal. Background Technology

[0002] Gate valves, also known as sluice gate valves, work by rotating the valve stem to raise or lower a gate connected to the lower part of the stem, thereby opening and closing pipelines, controlling liquid flow, and regulating and controlling the transported media. Traditional valve stem packings experience increased wear with increasing working pressure, becoming insufficient for optimal sealing conditions. Therefore, depending on the usage of the gate valve, regular leak checks are necessary, and damaged valve stem packing should be replaced promptly. This places high demands on the lifespan of the valve stem packing.

[0003] Patent CN203286123U discloses a valve stem sealing ring with a metal spring, comprising an annular base made of modified polytetrafluoroethylene, a groove on one side of the annular base, a metal spring in the groove, sealing lips on both the outer and inner circumferential surfaces of the annular base, the sealing lips being located on both sides of the groove, and multiple arc-shaped protrusions along the axial direction of the annular base forming a wave-shaped sealing lip, with a gasket abutting against the other side of the annular base relative to the groove.

[0004] The aforementioned valve stem sealing ring features a wavy sealing lip design with multiple arc-shaped protrusions, enhancing sealing performance. However, with prolonged use, friction reduces the thickness of the valve stem sealing packing, preventing the effective removal of friction debris. This debris blocks the gap between the lips, creating a smooth, straight surface, effectively reducing the preload. After use, the gap between the valve stem and the sealing packing widens, reducing the sealing effect and potentially leading to leakage. Especially under ultra-high pressure (172.5 MPa) and temperature ranges from -46°C to 180°C, the original valve stem sealing packing is more prone to damage and leakage, requiring more manpower and resources for maintenance and replacement, thus indirectly increasing operating costs. Utility Model Content

[0005] The purpose of this invention is to provide an ultra-high pressure valve stem seal to solve the problem in the prior art where the debris from frictional wear of the valve stem seal ring cannot be discharged, resulting in reduced sealing effect or even leakage.

[0006] To achieve the above objectives, this utility model provides an ultra-high pressure valve stem seal, including a sealing ring and a support ring disposed at the root of the sealing ring. The sealing ring includes a base and a sealing lip. The sealing lip is disposed at the top of the base away from the support ring. The outer side of the sealing lip is formed with a lip edge. The lip edge has a single-layer structure in the direction from the top to the root of the sealing ring. The lip edge has an outwardly convex curved surface, and the curved surface is smoothly connected to the outer wall of the base.

[0007] Preferably, the root of the base has a bevel and a connecting edge. There are two sets of bevels, which are symmetrically arranged on both sides of the base. The connecting edge connects the two sets of bevels. The top of the support ring is provided with a support groove. The support groove has side walls on both sides and a bottom wall connected between the side walls. The side walls are adapted to the bevels, and the bottom wall is adapted to the connecting edge. The root of the base is supported and arranged in the support groove.

[0008] Preferably, the sidewall and the bottom wall are connected by an arc, and the connecting edge and the inclined edge are connected by an arc.

[0009] Preferably, the support ring includes a first retaining ring and a second retaining ring arranged in layers, the first retaining ring being located between the second retaining ring and the sealing ring, the support groove being located on top of the first retaining ring, the first retaining ring being a polyetheretherketone (PEEK) component, and the second retaining ring being a metal component.

[0010] Preferably, the second retaining ring is made of brass.

[0011] Preferably, the sealing ring forms a groove between the sealing lips, and a U-shaped spring is provided in the groove, with the top of the U-shaped spring supporting the sealing lip;

[0012] The ultra-high pressure valve stem seal also includes a pressure ring, which has a T-shaped structure and the bottom end of the pressure ring supports the U-shaped spring.

[0013] Preferably, the top end of the sealing lip is provided with a flange extending into the groove, the top end of the U-shaped spring presses against the flange, and there is a radial gap between the flange and the pressure ring.

[0014] Compared with the prior art, the ultra-high pressure valve stem seal of this utility model has the following advantages: Only a single layer of lip edge is provided on the outer side of the sealing lip from top to root, reducing the number of lip edges. The curved surface of the lip edge is smoothly connected to the outer wall of the substrate, and there is a radial gap between the curved surface of the lip edge and the outer wall of the substrate. After the sealing lip experiences ultra-high pressure and high / low temperature conditions, the wear debris generated can be discharged from the bottom of the lip edge, which helps prevent debris accumulation and thus greatly reduces the risk of seal failure. As the service time increases and friction wears off, the cross-section of the sealing lip will become thinner. Due to the outward convexity of the curved surface of the lip edge, the thickness of the sealing lip is increased, thereby increasing the product's lifespan. Attached Figure Description

[0015] Figure 1 This is a structural schematic diagram of the ultra-high pressure valve stem seal of this utility model;

[0016] Figure 2 yes Figure 1 A schematic diagram of the sealing ring structure of an ultra-high pressure valve stem seal;

[0017] Figure 3 yes Figure 1 A schematic diagram of the structure of the first retaining ring of the ultra-high pressure valve stem seal.

[0018] In the figure, 1 is the sealing ring, 11 is the base, 111 is the bevel, 112 is the connecting edge, 12 is the sealing lip, 121 is the lip edge, 13 is the groove, 14 is the flange, 2 is the support ring, 21 is the first retaining ring, 22 is the second retaining ring, 23 is the support groove, 231 is the side wall, 232 is the bottom wall, 3 is the U-shaped spring, and 4 is the pressure ring. Detailed Implementation

[0019] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0020] A preferred embodiment of the ultra-high pressure valve stem seal of this utility model is as follows: Figures 1 to 3 As shown, the ultra-high pressure valve stem seal includes a sealing ring 1 and a support ring 2. The sealing ring 1 is the sealing body of the ultra-high pressure valve stem seal. The support ring 2 is located at the root of the sealing ring 1 and is used to provide axial support for the sealing ring 1. The root and top correspond to the force direction of the valve stem. The valve stem applies an axial force from the top of the seal to the root.

[0021] The sealing ring 1 includes a base 11 and sealing lips 12. The sealing lips 12 are located on the top of the base 11, away from the support ring 2. There are two sets of sealing lips 12, arranged symmetrically. The base 11 is the root structure of the sealing ring 1 and supports the sealing lips 12. When the sealing ring 1 is compressed, the sealing lips 12 expand outward, increasing the sealing effect. The outer side of the sealing lips 12 is formed with a lip edge 121, which refers to the side where the two sealing lips 12 are opposite to each other. The lip edge 121 is used to contact and seal with the valve stem.

[0022] The lip 121 has a single-layer structure from the top to the root of the sealing ring 1, meaning that there is only one set of lips 121 on the outer side of each sealing lip 12. This avoids gaps between multiple lip layers that could clog filler debris. After experiencing ultra-high pressure and high / low temperature conditions, the resulting wear debris can be discharged from the bottom, which helps prevent debris accumulation and greatly reduces the risk of seal failure. The lip 121 has an outwardly convex curved surface that is smoothly connected to the outer wall of the base 11. The outward convexity of the curved surface increases the thickness of the sealing lip 12, which can increase the service life when the sealing ring 1 experiences frictional wear. In this embodiment, the lip 121 itself is an interference fit design, which already ensures good sealing performance at low temperatures.

[0023] In this embodiment, the sealing ring 1 is made of modified PTFE (polytetrafluoroethylene) material with a fixed ratio. Carbon is added to the material, which can improve the hardness of PTFE and its resistance to high and low temperatures. At the same time, due to the properties of carbon, this product is more wear-resistant than ordinary PTFE, which improves the problem that the seal is difficult to withstand long-term use under ultra-high pressure (172.5MPa) and temperature conditions of -46 degrees Celsius to 180 degrees Celsius.

[0024] PTFE possesses excellent chemical stability, exhibiting strong resistance to most acids, alkalis, and organic solvents. This allows it to maintain its performance even in chemically treated and corrosive environments. PTFE materials are stronger than elastic materials, providing excellent wear resistance. Furthermore, PTFE is more wear-resistant than elastic materials. PTFE (polytetrafluoroethylene) itself has a self-lubricating effect; modified PTFE has a coefficient of friction of 0.277, minimizing friction and preventing excessive temperature increases in the sealing system due to friction. Due to the material's inherent properties, it significantly enhances the wear resistance of the sealing ring, thereby greatly extending the service life of the system seal.

[0025] This ultra-high pressure valve stem seal has only a single layer of lip 121 on the outer side of the sealing lip 12 from top to root, reducing the number of lip 121. The curved surface of the lip 121 is smoothly connected to the outer wall of the base 11, and there is a radial gap between the curved surface of the lip 121 and the outer wall of the base 11. After the sealing lip 12 has experienced ultra-high pressure and high and low temperature conditions, the wear debris generated can be discharged from the bottom of the lip 121, which helps to prevent debris accumulation and thus greatly reduces the risk of seal failure. As the service time increases and friction wears off, the cross section of the sealing lip 12 will become thinner. Since the curved surface of the lip 121 protrudes outward, the thickness of the sealing lip 12 is increased, thereby increasing the product's lifespan.

[0026] Preferably, the root of the base 11 has a bevel 111 and a connecting edge 112. There are two sets of bevels 111, which are symmetrically arranged on both sides of the base 11. The connecting edge 112 is connected between the two sets of bevels 111. The top of the support ring 2 is provided with a support groove 23. The support groove 23 has side walls 231 on both sides and a bottom wall 232 connected between the side walls 231. The side walls 231 are adapted to the bevels 111, and the bottom wall 232 is adapted to the connecting edge 112. The root of the base 11 is supported and arranged in the support groove 23.

[0027] The base 11 has a V-shaped design between its beveled edge 111 and connecting edge 112, and between its sidewall 231 and bottom wall 232. This design allows the base 11 to better fit the support ring 2 under ultra-high pressure and temperature, resulting in better contact between the sealing ring 1 and the support ring 2. Furthermore, the close fit of the base 11 to the support ring 2 significantly reduces the risk of material extrusion after use. Additionally, under high temperature and ultra-high pressure, the support ring 2 will experience high-temperature creep. In this case, the V-shaped structure at the base of the base 11 opens to both sides and fits tightly against the support groove 23, reducing gaps and protecting the support ring 2.

[0028] Preferably, the side wall 231 and the bottom wall 232 are connected by an arc, and the connecting edge 112 and the inclined edge 111 are connected by an arc.

[0029] The rounded transitions between the side wall 231 and the bottom wall 232, and between the connecting edge 112 and the inclined edge 111, can prevent stress concentration in the support ring 2 and greatly reduce the risk of tearing.

[0030] Preferably, the support ring 2 includes a first retaining ring 21 and a second retaining ring 22 arranged in layers. The first retaining ring 21 is located between the second retaining ring 22 and the sealing ring 1. The support groove 23 is located on top of the first retaining ring 21. The first retaining ring 21 is a polyetheretherketone (PEEK) component, and the second retaining ring 22 is a metal component.

[0031] The support ring 2 is formed by a first retaining ring 21 and a second retaining ring 22. The first retaining ring 21 is made of polyetheretherketone (PEEK). PEEK has wear resistance, high strength and rigidity, and excellent chemical stability. It has good resistance to various complex high temperature and high pressure and acids. In addition, since PEEK has good compressive strength but poor tensile strength, the first retaining ring 21 designed with PEEK as material is used under the sealing ring 1 to provide protection and compressive strength.

[0032] The second retaining ring 22 is a metal part. Metal has high processing precision, so it plays a key role in controlling the product gap and supports the first retaining ring 21, which can further reduce the gap.

[0033] Preferably, the second retaining ring 22 is made of brass.

[0034] Brass has good ductility and is softer than grooved cylinders, resulting in better compressive strength and less susceptibility to temperature changes compared to polyetheretherketone (PEEK). It is less prone to deformation and damage to the sealing grooves under high, low temperature, and ultra-high pressure conditions.

[0035] Preferably, the sealing ring 1 forms a groove 13 between the sealing lips 12, and a U-shaped spring 3 is provided in the groove 13, with the top of the U-shaped spring supporting the sealing lip 12;

[0036] The ultra-high pressure valve stem seal also includes a pressure ring 4, which has a T-shaped structure and a U-shaped spring 3 at its bottom.

[0037] A U-shaped spring 3 is installed in the groove 13 of the sealing ring 1, and the bottom end of the pressure ring 4 supports the U-shaped spring 3. The U-shaped spring 3 can open the sealing lips 12 on both sides, providing elastic sealing force for the sealing ring 1 and improving the sealing reliability of the sealing ring 1. The pressure ring 4 supports the U-shaped spring 3, and the other end of the pressure ring 4 can be connected to the valve stem to apply axial force to the U-shaped spring 3, so that the U-shaped spring 3 opens the sealing lips 12.

[0038] Preferably, the top end of the sealing lip 12 is provided with a flange 14 extending into the groove 13, the top end of the U-shaped spring 3 presses against the flange 14, and there is a radial gap between the flange 14 and the pressure ring 4.

[0039] There is a radial gap between the flange 14 and the pressure ring 4, which can prevent the U-shaped spring 3 and the sealing lip 12 from being compressed and play a role in protecting the U-shaped spring 3 and the sealing lip 12.

[0040] In summary, this utility model embodiment provides an ultra-high pressure valve stem seal, which has only a single layer of lip edge on the outer side of the sealing lip from top to root, reducing the number of lip edges. The curved surface of the lip edge is smoothly connected to the outer wall of the substrate, and there is a radial gap between the curved surface of the lip edge and the outer wall of the substrate. After the sealing lip has experienced ultra-high pressure and high and low temperature conditions, the wear debris generated can be discharged from the bottom of the lip edge, which helps to prevent debris accumulation and thus greatly reduces the risk of seal failure. As the service time increases and friction wears off, the cross-section of the sealing lip will become thinner. Since the curved surface of the lip edge protrudes outward, the thickness of the sealing lip is increased, thereby increasing the product's lifespan.

[0041] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A high-pressure valve stem seal, characterized in that, The sealing ring (1) includes a sealing ring (1) and a support ring (2) located at the root of the sealing ring (1). The sealing ring (1) includes a base (11) and a sealing lip (12). The sealing lip (12) is located on the top of the base (11) away from the support ring (2). The outer side of the sealing lip (12) is formed with a lip edge (121). The lip edge (121) has a single-layer structure in the direction from the top to the root of the sealing ring (1). The lip edge (121) has an outwardly protruding curved surface. The curved surface is smoothly connected to the outer wall of the base (11).

2. The ultra-high pressure valve stem seal according to claim 1, characterized in that, The base (11) has a hypotenuse (111) and a connecting edge (112) at its root. There are two sets of hypotenuses (111), which are symmetrically arranged on both sides of the base (11). The connecting edge (112) is connected between the two sets of hypotenuses (111). The top of the support ring (2) is provided with a support groove (23). The support groove (23) has side walls (231) on both sides and a bottom wall (232) connected between the side walls (231). The side walls (231) are adapted to the hypotenuses (111), and the bottom wall (232) is adapted to the connecting edge (112). The root of the base (11) is supported and arranged in the support groove (23).

3. The ultra-high pressure valve stem seal according to claim 2, characterized in that, The sidewall (231) and the bottom wall (232) are connected by an arc, and the connecting edge (112) and the inclined edge (111) are connected by an arc.

4. The ultra-high pressure valve stem seal according to claim 2, characterized in that, The support ring (2) includes a first retaining ring (21) and a second retaining ring (22) arranged in layers. The first retaining ring (21) is located between the second retaining ring (22) and the sealing ring (1). The support groove (23) is located on top of the first retaining ring (21). The first retaining ring (21) is a polyetheretherketone (PEEK) component, and the second retaining ring (22) is a metal component.

5. The ultra-high pressure valve stem seal according to claim 4, characterized in that, The second retaining ring (22) is made of brass.

6. The ultra-high pressure valve stem seal according to any one of claims 1-5, characterized in that, The sealing ring (1) forms a groove (13) between the sealing lips (12), and a U-shaped spring (3) is provided in the groove (13), with the top of the U-shaped spring (3) supporting the sealing lip (12). The ultra-high pressure valve stem seal also includes a pressure ring (4), which is a T-shaped structure, and the bottom end of the pressure ring (4) supports the U-shaped spring (3).

7. The ultra-high pressure valve stem seal according to claim 6, characterized in that, The sealing lip (12) has a flange (14) extending toward the groove (13) at its top end. The top end of the U-shaped spring (3) presses against the flange (14). There is a radial gap between the flange (14) and the pressure ring (4).

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