Large cast steel valve sealing structure

Abstract

The utility model discloses a large cast steel valve sealing structure, which belongs to the technical field of valve manufacture and comprises a base, a valve seat and a double-layer movable valve plate, and the base fixes the valve seat through a fastening bolt. Two inclined sealing parts are arranged on the inner wall of the valve seat, the inclined sealing parts and the movable valve plate form a sealing face, a right-angle avoiding face is arranged between the two sealing parts, and a middle cavity is formed. The complexity of a leakage path is increased, the sealing reliability is improved, meanwhile, a buffer space is provided for thermal expansion, and stress concentration and abrasion are reduced. The double-layer structure of the movable valve plate ensures precise attachment, and aligning notches are formed in the ends of all the layers so as to maintain proper intervals. Grooves with beveled edges are formed in the first sealing part and the second sealing part, and transition layers and surfacing metal layers are arranged in the grooves; the structure of the implementation mode can be used for variable working environments and extreme temperature conditions, it is ensured that the valve keeps excellent sealing effect and stability under various working conditions, meanwhile, the maintenance cost is reduced, and the production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to valve manufacturing technical field, especially, relate to a large -scale cast steel valve sealing structure. BACKGROUND

[0002] With the continuous progress of industrial technology, the performance and service life of valve equipment are put forward more strict requirements in manufacturing industry and social life, especially for large -scale cast steel valve. As the key component of fluid control system, the main function of valve is to accurately control medium flow, including cut off, regulation and guide. In order to improve its service life and sealing performance, users generally expect that the sealing surface of valve can show higher strength and excellent corrosion resistance.

[0003] Traditionally, in order to meet these needs, the industry usually adopts flexible sealing (such as elastic material) and plane sealing. However, in high temperature and high pressure environment, flexible sealing material is prone to deformation, aging and even rupture, thereby losing its sealing efficiency, and it is not suitable for application scenarios containing abrasive medium. Plane sealing faces the problem that two contact surfaces are difficult to be perfectly parallel and flat, especially under high load conditions, any slight deviation can cause serious leakage problem, and additional fastening device is needed, which increases the structural complexity and maintenance difficulty.

[0004] Therefore, the surfacing sealing technology has been widely used in large valve sealing. Surfacing adds a layer of alloy material with excellent mechanical properties and corrosion resistance on the surface of valve seat or closing piece, which significantly improves the overall performance of valve equipment. However, due to the combination of two materials with different thermal expansion coefficients in the surfacing process, cracks are easy to appear on the sealing surface. When these cracks are washed by fluid or gas in actual use, intergranular corrosion may occur, which affects the sealing performance and shortens the service life of valve. SUMMARY

[0005] The purpose of the utility model embodiment is to provide a large -scale cast steel valve sealing structure to meet the wear -resisting requirement of large -scale cast steel valve sealing surface, solve the problem that surfacing structure is easy to appear crack and prolong the service life of valve.

[0006] To solve the above technical problems, the utility model adopts the technical scheme of a large -scale cast steel valve sealing structure, which comprises a valve seat and a moving valve plate, a base, the valve seat is connected with the base through a fastening bolt, the inner wall of the valve seat is provided with a first sealing part and a second sealing part, the first sealing part and the second sealing part are two discontinuous inclined surfaces with the same angle, a right angle avoiding surface is arranged between the first sealing part and the second sealing part.

[0007] The first sealing part and the second sealing part are two discontinuous inclined surfaces with the same angle, and a right angle avoiding surface is arranged between the first sealing part and the second sealing part.

[0008] The mobile valve plate is a double-layer valve plate structure, the end of each layer of valve plate has the same inclination angle with the first sealing part and the second sealing part, and is respectively attached to the first sealing part and the second sealing part to form a sealing surface; a notch is arranged between the ends of the two layers of valve plate; the notch and the right-angle avoiding surface form a central control cavity.

[0009] Further, grooves are arranged on the first sealing surface and the second sealing surface, and the width and length of the grooves should be more than half of the width and length of the end of each layer of mobile valve plate respectively.

[0010] Further, the depth of the groove is 9±1mm, the bevel is arranged on the surfacing edge of the groove, the bevel of the groove edge is 35~45°, and the bottom of the groove is a plane.

[0011] Further, a transition layer is arranged on the inner surface of the groove, and a surfacing metal layer is arranged on the transition layer; the thickness of the transition layer is 3±1mm; and the thickness of the surfacing metal layer is 4~8mm.

[0012] Further, the transition layer is specifically a high-chromium molybdenum nickel alloy steel surfacing layer; and the surfacing metal layer is specifically a chromium molybdenum alloy steel surfacing layer.

[0013] Compared with the prior art, the utility model has the advantages that: the utility model first significantly enhances the sealing performance. By introducing an intermediate cavity between the valve seat and the mobile valve plate, the complexity and length of the medium leakage path are increased, the leakage resistance is effectively improved, and the leakage risk is reduced. Even if the sealing surface appears local failure (such as a small crack), since the double sealing surfaces work independently, single-point failure will not immediately lead to overall sealing failure, thereby greatly enhancing the reliability and safety of the system. In addition, the intermediate cavity provides a buffer space for thermal expansion, effectively alleviating the stress concentration problem caused by temperature changes, and avoiding the possible deformation or damage of the sealing surface.

[0014] Secondly, the utility model effectively reduces friction and wear. The design of the intermediate cavity reduces the direct contact area between the first sealing part, the second sealing part and the end of the mobile valve plate, not only reduces friction and wear, but also further prolongs the service life of the sealing assembly. This design is particularly suitable for valve applications that need to cope with variable working environments and extreme temperature conditions, ensuring that it can maintain excellent sealing effect and stability under various working conditions.

[0015] Furthermore, the utility model discloses solve the crack problem of traditional surfacing component. By introducing the transition layer and the groove between the valve seat base body and the surfacing layer, the mechanical properties and the thermal shrinkage rate of the transition layer are between the valve seat base body material and the surfacing material, thereby effectively reducing the thermal shrinkage difference between the two, significantly reducing the deformation risk caused by thermal stress, the groove releases the concentrated stress of surfacing, and improves the stability and durability of the overall structure. Especially for large components that are inconvenient to heat treatment, the composite process method combining the transition layer and the specific surfacing material can effectively overcome the material compatibility problem, ensure the ideal metallurgical bonding strength and microstructure stability, and finally realize excellent wear resistance and adaptability to complex working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0017] Figure 1 It is the valve sealing structure overview of this embodiment;

[0018] Figure 2 It is the valve sealing structure schematic view of this embodiment;

[0019] Figure 3 It is the groove schematic view of the sealing part surfacing piece of this embodiment.

[0020] In the drawing, 1, base; 2, valve seat; 201, first sealing part; 2011, surfacing metal layer; 2012, transition layer; 202, second sealing part; 3, moving valve plate; 4, fastening bolt. DETAILED DESCRIPTION

[0021] The technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0022] As Figures 1-2 In order to meet the performance requirements of the valve sealing surface, the utility model discloses a large cast steel valve sealing structure, and in some specific embodiments, the sealing structure includes base 1, valve seat 2 and moving valve plate 3.

[0023] In some specific embodiments, the base 1 is used to support and fix the valve seat 2, and the base 1 is connected with the valve seat 2 through fastening bolts 4; the inner wall of the valve seat 2 is provided with two inclined sealing parts including a first sealing part 201 and a second sealing part 202, and forms a sealing surface with the moving valve plate 3 to cut off the medium. The angles of the first sealing part 201 and the second sealing part 202 provided on the inner wall of the valve seat 2 are the same but not continuous, and a right-angled avoiding surface is arranged between the two inclined sealing parts, and a certain cavity is left between the moving valve plate 3 and the moving valve plate 3 after the valve seat 2 and the moving valve plate 3 cut off the medium; in this embodiment, the sealing structure of the introduced intermediate cavity can significantly improve the sealing performance. By increasing the complexity and length of the medium leakage path, this embodiment effectively improves the leakage resistance and reduces the risk of medium leakage. Even if the sealing surface appears local failure (such as a small crack), since the two sealing surfaces work independently, single-point failure will not immediately lead to overall sealing failure, thereby enhancing the reliability and safety of the system. In addition, the intermediate cavity provides a buffer space for thermal expansion, effectively alleviating the stress concentration problem caused by temperature changes, and avoiding the possible deformation or damage of the sealing surface caused by this. In addition, the arrangement of the cavity also reduces the direct contact area between the first sealing part 201, the second sealing part 202 and the end part of the moving valve plate 3, not only reducing friction and wear, but also further prolonging the service life of the sealing assembly. This embodiment is suitable for valve applications that need to cope with variable working environments and extreme temperature conditions, ensuring that it can maintain excellent sealing effect and stability under various working conditions.

[0024] In some specific embodiments, the moving valve plate 3 adopts a double-layer valve plate structure, and the end part of each layer of valve plate maintains the same inclination angle with the first sealing surface and the second sealing surface on the valve seat 2, and realizes precise fitting, ensuring the sealing performance. Between the end parts of the upper and lower valve plates, aligned notches are arranged to maintain a proper spacing therebetween, prevent direct contact, and ensure that the right-angled avoiding surfaces between the end parts of the upper and lower valve plates and the two inclined sealing surfaces of the valve seat 2 cooperate with each other to jointly form a hollow cavity.

[0025] As Figure 3 In some possible embodiments, grooves are arranged on the first sealing surface and the second sealing surface, and the depth of the grooves is 9±1mm; the length of the grooves is determined according to the design length and needs of the sealing surface, and in this embodiment, the length and width of the grooves are not less than half of the length and width of each end part of the moving valve plate 3; a transition layer 2012 with a thickness of 3±1mm is arranged on the inner wall part of the groove, preferably 3mm, preferably a high-chromium-molybdenum-nickel alloy steel cladding layer; a cladding metal layer 2011 with a thickness of 4-8mm is arranged on the transition layer 2012, preferably 6mm; preferably a chromium-molybdenum alloy steel cladding layer.

[0026] In some specific embodiments, the valve seat 2 base is made of cast steel. In this embodiment, a transition layer 2012 is introduced between the valve seat 2 base and the cladding layer. The mechanical properties and thermal shrinkage of the transition layer 2012 are between those of the valve seat 2 base material and the cladding material, thereby effectively reducing the thermal shrinkage difference between the two, significantly reducing the risk of deformation caused by thermal stress, and improving the stability and durability of the overall structure.

[0027] In some possible embodiments, the upper surface of the chromium-molybdenum alloy steel cladding layer forms a flat and continuous contact surface with the surrounding structure on the valve seat 2, ensuring seamless connection and good sealing performance between the valve seat 2 and the movable valve plate 3.

[0028] In some possible embodiments, the cladding edge of the groove is provided with a bevel, and the bottom of the groove is flat, with an inclination angle of 35° to 45° with respect to the horizontal reference surface. The bevel in this embodiment can prevent cracks in the cladding metal layer 2011 and the transition layer 2012 due to stress concentration.

[0029] In this embodiment, the provision of the transition layer 2012 not only significantly reduces the repair costs of cracks caused by improper cladding, but also significantly enhances the long-term service capability and sealing efficiency of the valve, fundamentally guarantees the consistency and reliability of product quality, and promotes the efficient operation of the overall manufacturing process. In particular, when facing large components that cannot be subjected to traditional heat treatment processes, by using a composite process scheme combining the transition layer 2012 and specific cladding materials, the material compatibility problem can be effectively overcome, the ideal metallurgical bonding strength and microstructure stability can be ensured, and finally excellent wear resistance and the ability to adapt to complex working conditions can be achieved.

[0030] The above only describes the preferred embodiments of the present application and is not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application are included in the protection scope of the present application.

Claims

1. A large-sized steel valve seal structure comprising a valve seat (2) and a moving valve plate (3), characterized in that, It also includes the base (1), the valve seat (2) and base (1) through the fastening bolt (4) connection; the valve seat (2) inner wall is provided with the first sealing part (201) and the second sealing part (202); The first sealing part (201) and the second sealing part (202) are two discontinuous but same angle inclined surface; the first sealing part (201) and the second sealing part (202) are provided with right angle avoiding surface; The mobile valve plate (3) is double-layer valve plate structure, the end of each layer valve plate is same with the first sealing part (201), the second sealing part (202) and the first sealing part (201) and the second sealing part (202) respectively adhere to constitute sealing surface; the gap is provided between the end of two layers of valve plate; the gap and the right angle avoiding surface constitute hollow cavity.

2. A large steel valve seal structure according to claim 1, wherein The first sealing part (201) and the second sealing part (202) are provided with groove, the width and length of the groove should exceed half of the width and length of the end of each layer of mobile valve plate (3) respectively.

3. A large steel valve seal structure according to claim 2, wherein The groove depth is 9±1mm, the groove edge is provided with bevel, the groove edge is inverted 35~45°bevel, and the groove bottom is plane.

4. A large steel valve seal structure according to claim 2, wherein The inner surface of the groove is provided with transition layer (2012), the transition layer (2012) is provided with surfacing metal layer (2011); the thickness of the transition layer (2012) is 3±1mm; the thickness of the surfacing metal layer (2011) is 4~8mm.

5. A large steel valve seal structure according to claim 4, wherein The transition layer (2012) is high chromium molybdenum nickel alloy steel surfacing layer; the surfacing metal layer (2011) is chromium molybdenum alloy steel surfacing layer.

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