A bearing seat oil seal for main valve of steam turbine

Abstract

The present application discloses a bearing seat oil seal for a main valve of a steam turbine, which relates to the field of steam turbines. The oil seal comprises an annular body, an annular metal frame buried in the body, and an annular lip-shaped sealing portion arranged inside the body, wherein the body is made of hydrogenated nitrile rubber, one axial side of which is the oil side, and the other side is the air side; a dustproof lip is extended from the lower end of the body to the air side; the lip-shaped sealing portion is made of fluororubber, which is connected to the lower end of the body through a connecting arm and is inclined to the oil side; the lower end of the lip-shaped sealing portion comprises an oil side lip surface facing the oil side and an air side lip surface facing the air side, and the oil side lip surface and the air side lip surface are connected to the sealing edge at the lower edge to form a lip end. The oil seal adopts composite materials, introduces a multilayer structure and improves the sealing shape, which can significantly improve the sealing effect and durability of the oil seal. This can not only improve the working efficiency of the steam turbine, but also reduce the maintenance frequency and reduce resource waste.

Description

Technical Field

[0001] The present application relates to the field of steam turbines, and in particular to a bearing seat oil seal for a main valve of a steam turbine. Background Art

[0002] Steam turbine is a kind of equipment widely used in the power industry. It converts the thermal energy of steam into mechanical energy to drive generators and other mechanical devices. The main valve plays a key role in the operation of the steam turbine. It is responsible for regulating the flow of steam to ensure the efficiency and safety of the steam turbine. To ensure the normal operation of the main valve, the design and application of the bearing seat oil seal are crucial. The main function of the bearing seat oil seal is to prevent the leakage of lubricating oil and effectively prevent external impurities from entering the bearing seat, thereby ensuring the long-term stable operation of the steam turbine under high temperature and high pressure environment.

[0003] The current bearing seat oil seal structure usually relies on the direct contact between the elastic sealing ring and the bearing surface to achieve sealing. However, this traditional design has several significant deficiencies in practical applications. First, existing oil seals generally adopt a single material design. Although this design has advantages in production cost, it is difficult to achieve ideal results in terms of performance. Although the use of high-cost materials can provide good high temperature resistance, wear resistance and corrosion resistance, its price is significantly increased and cannot be widely adopted. Although the use of some conventional materials has a lower cost, it performs poorly in high temperature and high pressure working environments, and is prone to aging, deformation and wear, resulting in reduced sealing performance, which in turn causes lubricating oil leakage problems, increasing the maintenance frequency and overall cost of the equipment.

[0004] Secondly, the contact surface design of existing oil seals is often a simple plane. Although this design is convenient in manufacturing, in actual applications, plane contact cannot effectively form an ideal sealing effect. Microscopic unevenness of the surface may lead to loose contact, resulting in oil leakage under high pressure conditions. In addition, plane contact will also produce large friction resistance, which not only affects the normal operation efficiency of the oil seal, but also may cause energy waste and excessive wear of the equipment.

[0005] In terms of structure, the current oil seal design still has significant room for improvement and necessity. Therefore, it is particularly important to develop a new type of bearing seat oil seal for the main valve of the steam turbine. Its potential technological innovation will provide a strong guarantee for the long-term stable operation of the steam turbine. Summary of the invention

[0006] The purpose of this application is to overcome at least one of the shortcomings of the prior art and provide a bearing seat oil seal for a main valve of a steam turbine, which uses a composite material, introduces a multi-layer structure and improves the sealing shape, which can significantly improve the sealing effect and durability of the oil seal. This can not only improve the working efficiency of the steam turbine, but also reduce the maintenance frequency, reduce resource waste, and thus improve the overall economic benefits.

[0007] To achieve the above-mentioned purpose, the present application discloses a bearing seat oil seal for a main valve of a steam turbine, the oil seal comprising an annular body, an annular metal frame buried in the body, and an annular lip-shaped sealing portion arranged inside the body, wherein the body is made of hydrogenated nitrile rubber, one axial side of the body is an oil side, and the other side is an air side; a dust lip extends from the lower end of the body toward the air side;

[0008] The lip seal is made of fluororubber, connected to the lower end of the body through a connecting arm and inclined toward the oil side;

[0009] The lower end of the lip seal portion includes an oil side lip surface facing the oil side and an air side lip surface facing the air side. The oil side lip surface and the air side lip surface are connected at the sealing edge at the lower edge to form a lip end. When working, the lip end of the lip seal portion is interference fit with the bearing seat, so that the sealing edge and adjacent parts are squeezed to form a sealing surface, ensuring effective isolation between oil and air;

[0010] A plurality of oil storage grooves are arranged circumferentially along the upper edge of the oil side lip surface, close to the sealing edge position. The groove of the oil storage groove is arc-shaped at one end close to the gas side lip surface, and gradually narrows to form a sharp angle structure at one end close to the oil side lip surface. The whole gradually shrinks downward from the arc edge, and finally forms an acute angle at the bottom end, forming a water drop shape;

[0011] A plurality of pumping protrusions are arranged circumferentially along the gas side lip surface near the sealing edge. The pumping protrusion is arc-shaped at one end near the gas side lip surface and gradually narrows to form a sharp angle at one end near the oil side lip surface. The whole gradually shrinks downward from the arc edge and finally forms an acute angle at the bottom end, forming a water drop-shaped protrusion;

[0012] The connecting arm is connected to a sealing lip located between the dust lip and the lip-shaped sealing portion and inclined toward the air side; the sealing lip is made of polytetrafluoroethylene;

[0013] The metal frame is made of No. 45 steel, including an inverted L-shaped upper part located in the body and a lower part extending from the lower end of the upper part into the connecting arm and in the same direction as the connecting arm. The length of the lower part is 0.3-0.6 of the connecting arm; the thickness of the lower part is 0.5-0.7 of the upper part.

[0014] In some embodiments, the body, the lip seal portion and the sealing lip are vulcanized into one piece.

[0015] In some embodiments, the angle between the oil-side lip surface of the lip seal and the horizontal plane is 45 degrees, and the angle between the gas-side lip surface and the horizontal plane is 20 degrees.

[0016] In some embodiments, the elastic modulus of the lip seal is 5-8 MPa, and the Poisson's ratio is 0.47-0.49.

[0017] In some embodiments, the roughness peak radius of the oil side lip surface and the air side lip surface of the lip seal portion is 1 μm, the roughness is 0.65 μm, and the roughness peak density is 10 13 m -2 , the rough peak aspect ratio is 1.

[0018] In some embodiments, the oil storage groove has a depth of 3-4 μm, an acute angle at the bottom of the groove is 20-45 μm away from the sealing edge, a maximum groove width of 16-25 μm, and a distance between adjacent grooves of 60-120 μm; the pumping protrusion is adapted to the shape and size of the oil storage groove.

[0019] Furthermore, adjacent oil storage grooves are connected via an annular groove arranged along the circumference of the lip seal portion.

[0020] In some embodiments, an annular groove with a major arc cross-section is provided on the upper end surface of the lip seal portion in the circumferential direction, and a tightening spring is installed in the annular groove. The tightening spring is used to apply radial pressure to the lip seal portion.

[0021] Furthermore, the tightening spring is formed by winding a carbon steel wire, and the spring coefficient is 13-38N / mm.

[0022] In some embodiments, the width of the sealing surface of the lip seal when in operation is 0.3-0.4 mm.

[0023] In some embodiments, an annular metal spring frame is disposed inside the sealing lip.

[0024] In some embodiments, the elastic modulus of the sealing lip is 7-8 MPa, and the Poisson's ratio is 0.47-0.49.

[0025] In some embodiments, the upper surface of the connecting arm has an arc-shaped protrusion, and the torsional strength is improved by the arc-shaped protrusion.

[0026] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0027] 1. Multi-material design: The use of composite materials significantly improves the durability and sealing performance of the oil seal in high temperature and high pressure environments, reducing the risk of lubricating oil leakage.

[0028] 2. Optimize the contact surface structure: The improved contact surface design not only enhances the sealing effect, but also effectively reduces the friction resistance, thereby improving the operating efficiency of the oil seal.

[0029] 3. Reduce maintenance frequency: As the durability and sealing of the oil seal are improved, the maintenance frequency of the equipment is reduced, thereby reducing the overall operating cost.

[0030] 4. Improve safety: effectively prevent lubricating oil leakage, reduce the risk of equipment failure caused by insufficient lubrication, and improve the safety and reliability of the steam turbine.

[0031] The above-listed beneficial effects are not exhaustive of all advantages. Other potential beneficial effects and detailed technical implementations will be further disclosed in the examples or other description parts of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] After reading the following detailed description in conjunction with the accompanying drawings, you will have a better understanding of various aspects of the present disclosure. The positions, sizes, and ranges of various structures shown in the accompanying drawings sometimes do not represent the actual positions, sizes, and ranges. In the accompanying drawings:

[0033] Figure 1 It is a structural schematic diagram of an embodiment disclosed in this application.

[0034] Figure 2 It is a structural schematic diagram of an embodiment disclosed in the present application from another perspective.

[0035] Figure 3 yes Figure 2 Schematic diagram of the cross section of AA.

[0036] Figure 4 yes Figure 3 Enlarged view of point A in .

[0037] Figure 5 yes Figure 3 Enlarged view of point B in .

[0038] Figure 6 It is a structural schematic diagram of an embodiment disclosed in the present application from another perspective. DETAILED DESCRIPTION

[0039] The present disclosure will be described below with reference to the accompanying drawings, wherein the accompanying drawings illustrate several embodiments of the present disclosure. However, it should be understood that the present disclosure can be presented in a variety of different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present disclosure more complete and fully illustrate the scope of protection of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide more additional embodiments.

[0040] It should be understood that the same reference numerals represent the same elements throughout the drawings. In the drawings, the dimensions of certain features may be distorted for clarity.

[0041] It should be understood that the words used in the specification are only used to describe specific embodiments and are not intended to limit the present disclosure. All terms (including technical terms and scientific terms) used in the specification have the meanings commonly understood by those skilled in the art unless otherwise defined. For the sake of brevity and / or clarity, the techniques, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorized specification.

[0042] The singular forms "a", "said" and "the" used in the specification include plural forms unless clearly indicated. The words "include", "comprise" and "contain" used in the specification indicate the presence of the claimed features, but do not exclude the presence of one or more other features. The word "and / or" used in the specification includes any and all combinations of one or more of the relevant listed items. Example

[0043] like Figure 1-6 As shown, the turbine main valve bearing seat oil seal described in this embodiment is a highly innovative sealing device, and its design fully considers the particularity and stringent requirements of the turbine working environment. The oil seal can not only maintain excellent sealing performance under high-speed rotation, high temperature and high pressure environment, but also significantly extend the service life and reduce maintenance costs.

[0044] The core structure of the oil seal includes an annular body 1 , a metal skeleton 3 and a lip seal portion 4 .

[0045] Specifically, the annular body 1 is made of hydrogenated nitrile rubber, which is selected because of its excellent oil resistance, heat resistance and mechanical strength. When the steam turbine is working, the temperature around the bearing seat may reach above 120°C, and hydrogenated nitrile rubber can still maintain good elasticity and sealing performance at this temperature.

[0046] In this embodiment, one side of the body 1 is defined as the oil side d, and the other side opposite thereto is defined as the air side c. Such clear definition is helpful to optimize the design and function of each part.

[0047] The dust lip 2 extending from the lower end of the body 1 is an important auxiliary sealing structure. The dust lip 2 is made of the same material as the body 1 and extends at an angle of 45 degrees to the air side c. Its function is not limited to blocking external dust and impurities, but also to balance the pressure difference between the oil side d and the air side c to a certain extent, reducing the load on the main sealing area.

[0048] In this embodiment, the metal skeleton 3 embedded in the body 1 is made of 45 steel. 45 steel is selected because it has excellent mechanical properties, especially its elastic modulus and yield strength can meet the requirements of high-speed rotation environment. The metal skeleton 3 has an upper part 301 and a lower part 302 in structure: the upper part 301 is located in the body 1, providing rigid support for the entire oil seal; the lower part 302 connected to the upper part 301 extends into the connecting arm 5 connected to the lip seal 4, which not only enhances the strength of the connecting arm 5, but also provides the necessary deformation space when the oil seal is installed, ensuring that the lip seal 4 and the shaft maintain an appropriate contact pressure.

[0049] More specifically, the length of the lower portion of the metal skeleton 3 is 0.3-0.6 times that of the connecting arm 5 . This ratio is an optimal value obtained through a large number of experiments and calculations, and can ensure sufficient strength without excessively restricting the elastic deformation of the connecting arm 5 .

[0050] In addition, the upper surface of the connecting arm 5 has an arc-shaped protrusion 501 , and the arc-shaped protrusion 501 improves the torsional strength.

[0051] In this embodiment, the lip seal 4 is the core component of the entire oil seal and is made of fluororubber. Fluororubber is selected as the material of this component because it has excellent heat resistance (can work for a long time at above 250°C), oil resistance and chemical stability. In the working environment of the steam turbine, it may be exposed to various lubricating oils and cleaning agents, and fluororubber can resist the erosion of these chemicals well. The lip seal 4 is connected to the lower end of the body 1 through the connecting arm 5, and is inclined to the oil side d. This inclined design is very critical. It can apply a certain pre-pressure to the shaft in static state to ensure the initial sealing effect. At the same time, during dynamic operation, due to the effect of fluid pressure, this inclination can also generate additional sealing force.

[0052] The lower end of the lip seal 4 includes an oil-side lip surface 401 facing the oil side d and an air-side lip surface 402 facing the air side c. The two lip surfaces 401 and 402 meet at the lower edge to form a sharp sealing edge 403, and then form a lip end. When the oil seal is installed in place and starts working, the lip end of the lip seal 4 and the bearing seat are interference fit, so that the sealing edge 403 and its surrounding area are squeezed to form an effective sealing surface. This design ensures complete isolation between oil and air, preventing oil leakage and air entry. The width of the sealing surface is controlled within the range of 0.3-0.4mm, which is a result of precise calculation. A sealing surface that is too narrow may cause excessive local pressure and accelerate wear; while a sealing surface that is too wide may increase unnecessary friction. A width of 0.3-0.4mm can achieve the best balance between the two.

[0053] On the oil side lip surface 401, a series of oil storage grooves 4001 are evenly distributed along the circumference. These grooves 4001 are arc-shaped at the end close to the air side c, and gradually narrow at the end close to the oil side d, eventually forming a sharp angle. Overall, these oil storage grooves 4001 present a shape similar to a water drop, which gradually shrinks downward from the arc edge to form an acute angle at the bottom. This unique shape design can not only effectively store lubricating oil, but also produce a dynamic pumping effect during the rotation of the shaft.

[0054] It should be noted that the oil storage groove 4001 in the figure is not of actual size and proportion, but is enlarged and scaled up for display purposes only to express the structure and cannot be used as a reference for specific size and density settings.

[0055] Specifically, when the shaft rotates at high speed, the oil storage groove 4001 will deform slightly due to centrifugal force and fluid dynamic effects. The arc end of the oil storage groove 4001 has a relatively large deformation due to its large radius of curvature, while the pointed end has a relatively small deformation due to its sharp shape. This asymmetric deformation results in the formation of a tiny fluid channel in the oil storage groove 4001, whose cross-sectional area gradually decreases from the arc end to the pointed end. According to the principles of fluid mechanics, a pressure difference will be generated when the fluid passes through this variable cross-section channel, thereby forming a tiny pumping effect, pumping the oil from the arc end to the pointed end, that is, pumping to the oil side d.

[0056] Corresponding to the oil storage groove 4001, a series of pumping protrusions 4002 are designed on the air side lip surface 402. These pumping protrusions 4002 are also evenly distributed along the circumference, close to the sealing edge 403. Their shape is similar to the oil storage groove 4001, and they also present a teardrop-shaped structure: the end close to the air side c is arc-shaped, and the end close to the oil side d gradually narrows to form a sharp angle. The whole gradually shrinks downward from the arc edge, and finally forms an acute angle at the bottom. The purpose of this design is to produce a small pumping effect during the rotation of the shaft, and pump the oil that may penetrate into the air side back to the oil side.

[0057] The pumping protrusion 4002 and the oil storage groove 4001 are precisely matched in shape and size. This matching design not only enhances the overall sealing effect, but also produces a unique fluid mechanics effect during dynamic operation. When the shaft rotates, the concave-convex structure formed by the pumping protrusion 4002 and the plane will be compressed, resulting in local stress concentration. The rotation of the shaft will also generate shear stress on these structures, causing the concave and convex to deform slightly in the tangential direction. This deformation causes tiny fluid channels to form between the concave and convex, which are actually a series of micropores deflected in the axial direction.

[0058] The formation of these microporous groove structures leads to two fluid flows in opposite directions: one is the leakage flow from the oil side d to the air side c, and the other is the pumping flow from the air side c to the oil side d. Due to the asymmetry of the concave-convex structure, especially the uneven pressure distribution caused by the water droplet-shaped design, the concave-convex structure undergoes asymmetric deformation. The maximum value of this asymmetric deformation occurs on the fluid side (i.e., the oil side d), resulting in an asymmetric distribution of the formed micropores. As a result of this asymmetric distribution, the reverse pumping fluid flow to the fluid side (oil side d) is higher than the leakage flow to the air side c.

[0059] This ingenious design realizes a self-balancing sealing system: even if a small amount of oil penetrates into the air side c, it will be pumped back to the oil side d under the rotation of the shaft. This not only improves the reliability of the seal, but also reduces oil loss and extends the maintenance cycle of the entire system.

[0060] In order to further optimize the sealing performance, the surface roughness parameters of the lip seal 4 are also carefully designed. The roughness peak radius of the oil side lip surface 401 and the gas side lip surface 402 is 1 μm, the roughness is 0.65 μm, and the roughness peak density is 10 13 m -2 , and the roughness peak aspect ratio is 1. These parameters are selected to minimize wear while providing sufficient friction. The presence of roughness peaks can also increase the retention space of lubricating oil on a microscopic scale, further improving lubrication conditions.

[0061] In addition, further, the specific dimensions of the oil storage groove 4001 and the pumping protrusion 4002 have also been accurately calculated and optimized. The groove depth of the oil storage groove 4001 is 3-4μm, which can store enough lubricating oil without excessively affecting the overall rigidity of the sealing lip. The distance between the acute angle at the bottom of the groove and the sealing edge 403 is 20-45μm. This distance ensures that the groove can effectively supply oil to the sealing edge 403 without excessively weakening the strength of the sealing edge 403. The maximum width of the groove is 16-25μm, and the distance between adjacent grooves is 60-120μm. The selection of these parameters takes into account the fluid mechanics characteristics and material strength requirements, and can provide sufficient oil storage space while maintaining the integrity of the overall structure of the lip-shaped sealing part. Similarly, the height of the pumping protrusion 4002 is also 3-4μm.

[0062] In order to further enhance the lubrication effect, adjacent oil storage grooves 4001 are connected by an annular groove 4003 arranged along the circumference of the lip seal 4. This design allows the lubricating oil to flow between different oil storage grooves 4001, ensuring that the entire sealing surface can be fully lubricated.

[0063] It should be noted that, as a preference, the depth of the annular groove 4003 is slightly smaller than the oil storage groove 4001, so that the overall strength of the oil seal will not be excessively affected while ensuring the flow of oil.

[0064] On the upper end surface of the lip seal 4, an annular groove 404 with a superior arc cross section is provided along the circumferential direction for mounting a fastening spring 6. The fastening spring 6 is wound from a carbon steel wire, and its spring constant is 13-38N / mm. The function of the fastening spring 6 is to apply radial pressure to the lip seal 4 to ensure that the sealing surface is always in close contact with the shaft, and to maintain effective sealing even when the shaft is slightly deformed or vibrated. The preload of the fastening spring 6 is precisely calculated to provide sufficient sealing pressure while minimizing additional friction.

[0065] In this embodiment, a sealing lip 7 made of polytetrafluoroethylene (PTFE) is also provided on the connecting arm 5. The sealing lip 7 is located between the dust lip 2 and the lip seal 4 and is deflected toward the air side c. PTFE is selected as the material because it has an extremely low friction coefficient (about 0.1) and excellent chemical resistance, and can provide auxiliary sealing without adding additional friction. PTFE has a wide operating temperature range (-200°C to 260°C), which fully meets the working requirements of the steam turbine. The presence of the sealing lip 7 further enhances the reliability of the entire sealing system and provides additional protection for the main seal.

[0066] It is worth noting that a ring-shaped metal spring skeleton 701 is also provided in the sealing lip 7. The metal spring skeleton 701 is made of elastic stainless steel, which enhances the rigidity of the sealing lip 701 and prevents it from being deformed under the airflow generated by high-speed rotation. At the same time, the metal spring skeleton 701 can also provide a certain elastic support so that the sealing lip 7 can adapt to the slight vibration and vibration of the shaft. The elastic modulus of the sealing lip 7 is 7-8 MPa and the Poisson's ratio is 0.47-0.49. These parameters enable it to have a certain elastic deformation ability while maintaining sufficient rigidity to adapt to changes in the working environment.

[0067] In actual application, the body 1, the lip seal 4 and the sealing lip 2 are formed into a whole through the vulcanization process. This integrated structure not only enhances the bonding strength between the components, but also eliminates the possible tiny gaps, further improving the reliability of the seal. During the vulcanization process, the control of temperature and pressure is very critical to ensure that a strong chemical bond is formed between the components without affecting the original properties of the materials.

[0068] This innovative oil seal design has shown excellent performance in practical applications. Through these fine designs and parameter control, the main valve bearing oil seal of the steam turbine can work stably in harsh environments of high temperature, high pressure and high speed, ensuring effective isolation of lubricating oil, reducing equipment wear, extending equipment service life, and improving the overall operating efficiency and safety of the steam turbine.

[0069] Although the exemplary embodiments of the present disclosure have been described, it should be understood by those skilled in the art that various changes and modifications can be made to the exemplary embodiments of the present disclosure without departing from the spirit and scope of the present disclosure in essence. Therefore, all changes and modifications are included in the scope of protection of the present disclosure as defined by the claims. The present disclosure is defined by the appended claims, and the equivalents of these claims are also included.

Claims

1. A bearing seat oil seal for a main valve of a steam turbine, characterized in that: The oil seal comprises: an annular body, an annular metal frame buried in the body, and an annular lip-shaped sealing portion arranged inside the body, wherein the body is made of hydrogenated nitrile rubber, one axial side of the body is the oil side, and the other side is the air side; a dust lip extends from the lower end of the body toward the air side; The lip seal is made of fluororubber, connected to the lower end of the body through a connecting arm and inclined toward the oil side; The lower end of the lip seal portion includes an oil side lip surface facing the oil side and an air side lip surface facing the air side. The oil side lip surface and the air side lip surface are connected at the sealing edge at the lower edge to form a lip end. When working, the lip end of the lip seal portion is interference fit with the bearing seat, so that the sealing edge and adjacent parts are squeezed to form a sealing surface, ensuring effective isolation between oil and air; A plurality of oil storage grooves are arranged circumferentially along the upper edge of the oil side lip surface, close to the sealing edge position. The groove of the oil storage groove is arc-shaped at one end close to the gas side lip surface, and gradually narrows to form a sharp angle structure at one end close to the oil side lip surface. The whole gradually shrinks downward from the arc edge, and finally forms an acute angle at the bottom end, forming a water drop shape; A plurality of pumping protrusions are arranged circumferentially along the gas side lip surface near the sealing edge. The pumping protrusion is arc-shaped at one end near the gas side lip surface and gradually narrows to form a sharp angle at one end near the oil side lip surface. The whole gradually shrinks downward from the arc edge and finally forms an acute angle at the bottom end, forming a water drop-shaped protrusion; The connecting arm is connected to a sealing lip located between the dust lip and the lip-shaped sealing portion and inclined toward the air side; the sealing lip is made of polytetrafluoroethylene; The metal frame is made of 45# steel, including an inverted L-shaped upper portion located in the body and a lower portion extending from the lower end of the upper portion into the connecting arm and in the same direction as the connecting arm, the length of the lower portion is 0.3-0.6 of the connecting arm; the thickness of the lower portion is 0.5-0.7 of the upper portion; The body, the lip-shaped sealing portion and the sealing lip are vulcanized into one piece; The angle between the oil-side lip surface of the lip seal and the horizontal plane is 45 degrees, and the angle between the gas-side lip surface and the horizontal plane is 20 degrees.

2. A bearing seat oil seal for a main valve of a steam turbine as claimed in claim 1, characterized in that: The elastic modulus of the lip seal is 5-8 MPa, and the Poisson's ratio is 0.47-0.

49.

3. A bearing seat oil seal for a main valve of a steam turbine as claimed in claim 1, characterized in that: The roughness peak radius of the oil side lip surface and the gas side lip surface in the lip seal portion is 1 μm, the roughness is 0.65 μm, and the roughness peak density is 10 13 m -2 , the rough peak aspect ratio is 1.

4. A bearing seat oil seal for a main valve of a steam turbine as claimed in claim 1, characterized in that: An annular groove with a major arc cross section is provided on the upper end surface of the lip seal portion in the circumferential direction, and a fastening spring is installed in the annular groove. The fastening spring is used to apply radial pressure to the lip seal portion.

5. A bearing seat oil seal for a main valve of a steam turbine as claimed in claim 4, characterized in that: The fastening spring is formed by winding a carbon steel wire, and the spring coefficient is 13-38N / mm.

6. A bearing seat oil seal for a main valve of a steam turbine as claimed in claim 1, characterized in that: The width of the sealing surface of the lip seal when in operation is 0.3-0.4 mm.

7. A bearing seat oil seal for a main valve of a steam turbine as claimed in claim 1, characterized in that: An annular metal spring frame is arranged inside the sealing lip.

8. A bearing seat oil seal for a main valve of a steam turbine as claimed in claim 1, characterized in that: The elastic modulus of the sealing lip is 7-8 MPa and the Poisson's ratio is 0.47-0.

49.

9. A bearing seat oil seal for a main valve of a steam turbine as claimed in claim 1, characterized in that: The upper surface of the connecting arm is provided with an arc-shaped protrusion, and the torsional strength is improved by the arc-shaped protrusion.

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