A new high differential pressure valve seat sealing structure

Abstract

The present invention relates to the technical field of valve sealing structures, and specifically discloses a novel high-pressure differential valve seat sealing structure, which includes a valve body and a valve seat arranged in a stepped hole of the valve body. A sleeve is provided above the valve seat, and a medium flow through hole is provided on the sleeve. A valve core is arranged in the sleeve. A stepped hole is arranged in the valve seat, and a sealing member is arranged in the large hole of the valve seat. The sealing member is made of a non-metallic material and is hollow. A support sleeve is arranged at the stepped hole of the sealing member. The lower end of the support sleeve fits with the inner hole of the valve seat and extends outside the valve seat. A locking nut is arranged on the outer side of the lower end of the support sleeve, and an elastic element is arranged between the locking nut and the valve seat. The lower end of the valve core is respectively provided with a first inclined surface and a second inclined surface that cooperate with the upper end surface of the sealing member and the upper end surface of the support sleeve. The present invention can effectively utilize the characteristics of cold plastic deformation of the sealing member material to solve the problem of high-pressure differential load conditions, especially the problem of zero-leakage sealing that cannot be achieved in large-diameter valves.

Description

Technical Field

[0001] The present invention relates to the technical field of valve sealing structures, and particularly to a novel high differential pressure valve seat sealing structure. Background Art

[0002] In an ultra-supercritical thermal power unit system, the operating conditions of high-end key valves are harsh. In order to meet the actual operating conditions, the valve leakage rate is required to reach Class V or zero leakage. Due to the relatively high operating differential pressure of the valve, the sealing specific pressure is large, and the yield point of soft sealing materials is generally low, so they cannot be directly applied.

[0003] At present, the main method to solve such problems is to adopt a metal hard sealing structure. Tungsten carbide is surfacing welded on the sealing surface of the metal material to increase the allowable sealing specific pressure to meet the sealing specific pressure requirements. However, it is very difficult for the metal hard seal to achieve Class V or zero leakage, especially for large-diameter valves, and the manufacturing cost is high, and the maintenance and repair are difficult. Summary of the Invention

[0004] The purpose of the present invention is to provide a novel high differential pressure valve seat sealing structure, which can effectively solve the problem of unable to achieve zero leakage sealing under high differential pressure load conditions, especially for large-diameter valves. Among them, when the acting force is less than the material yield point of the seal, reliable sealing can be achieved by using the elastic deformation of the seal; when the acting force exceeds the material yield point of the seal, the seal can generate plastic deformation within the deformation space to fill the voids and achieve the sealing effect, and the sealing load that can be borne is several times that of the traditional soft sealing structure.

[0005] To solve the above technical problems, the present invention provides a novel high differential pressure valve seat sealing structure, including a valve body and a valve seat arranged in a stepped hole of the valve body. A sleeve is arranged above the valve seat, a medium flow through hole is arranged on the sleeve, and a valve core is arranged in the sleeve;

[0006] A stepped hole is arranged in the valve seat, a seal is arranged in the large hole of the valve seat. The seal is hollow, and a support sleeve is arranged at the stepped hole of the seal. The lower end of the support sleeve fits with the inner hole of the valve seat and extends outside the valve seat. A locking nut is arranged on the outer side of the lower end of the support sleeve, and an elastic element is arranged between the locking nut and the valve seat. The elastic element is sleeved on the outer side of the support sleeve;

[0007] The lower end of the valve core is respectively provided with a first inclined surface and a second inclined surface that cooperate with the upper end surface of the seal and the upper end surface of the support sleeve.

[0008] Further, the upper end face of the seal forms a first sealing surface with the first inclined surface, the stepped hole connecting portion of the seal forms a second sealing surface with the inclined surface of the support sleeve, the lower end face of the seal forms a third sealing surface with the conical surface of the valve seat, and the second inclined surface and the inner hole of the support sleeve form a fourth sealing surface.

[0009] Further, a limit step is provided at the upper end of the valve core, and the limit step cooperates with the upper end of the valve seat.

[0010] Further, a cylindrical section is provided between the first inclined surface and the second inclined surface. The diameter of the cylindrical section is larger than the diameter of the small hole of the seal, and the diameter of the cylindrical section is smaller than the diameter of the large hole of the seal.

[0011] Further, the seal is made of non-metallic material, and a deformation space of the seal is formed between the seal, the valve core and the support sleeve.

[0012] Further, a sealing gasket is provided between the valve seat and the valve body.

[0013] Further, the inner diameter of the sleeve is larger than the inner diameter of the inner hole of the valve seat.

[0014] Further, the lower end of the valve seat includes a first boss section, a second boss section and a first cylindrical section formed integrally. The sealing gasket is arranged at the first boss section. The second boss section fits with the stepped surface of the valve body, and a gap is provided between the first cylindrical section and the valve body.

[0015] Further, the upper end of the valve seat includes a third boss section and a second cylindrical section formed integrally. The outer side section of the lower end of the sleeve fits with the third boss section, and the inner side section fits with the second cylindrical section.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. The present invention can effectively solve the problem of high differential pressure load conditions, especially the problem of zero-leakage sealing that cannot be achieved in large-diameter valves. Among them, when the acting force is less than the material yield point of the seal, reliable sealing can be achieved by using the elastic deformation of the seal; when the acting force exceeds the material yield point of the seal, the seal can produce plastic deformation in the deformation space to fill the gap and achieve the sealing effect, and the sealing load that can be borne is several times that of the traditional soft-sealing structure.

[0018] 2. Through the design of the first sealing surface, the second sealing surface, the third sealing surface and the fourth sealing surface, the sealing effect is better.

[0019] 3. The design of the limiting step can make the limiting step contact the upper end face of the valve seat when the load reaches the designed pressure value. The valve core cannot push the support sleeve to continue compressing the sealing space where the seal is located, achieving the purpose of limiting the highest limit load pressure and ensuring reliable sealing.

[0020] 4. The design of the elastic element can compensate for the clearance caused by the downward movement of the support sleeve under load, prevent loosening due to compression deformation, and improve the sealing effect.

[0021] 5. In the structural design of the valve seat, the lower end of the valve seat includes a first boss section, a second boss section, and a first cylindrical section formed integrally. The sealing gasket is arranged at the first boss section, and the second boss section fits with the stepped surface of the valve body, which can improve the sealing effect between the valve seat and the valve body; the upper end of the valve seat includes a second boss section and a second cylindrical section formed integrally. The outer side section of the lower end of the sleeve fits with the second boss section, and the inner side section fits with the second cylindrical section, which can improve the sealing effect between the sleeve and the valve seat. Brief Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 is a schematic structural view of the novel high-pressure differential valve seat sealing structure of the present invention in a state where the acting force is less than the yield point of the seal material;

[0024] Figure 2 is a schematic structural view of the novel high-pressure differential valve seat sealing structure of the present invention in a state where the acting force is greater than the yield point of the seal material;

[0025] Figure 3 is a schematic structural view of the novel high-pressure differential valve seat sealing structure of the present invention in a state where the acting force is less than the yield point of the seal material;

[0026] In the figure: 1-valve body, 2-valve seat, 3-sleeve, 4-valve core, 5-seal, 6-support sleeve, 7-lock nut, 8-elastic element, 9-sealing gasket, 10-deformation space, 21-first boss section, 22-second boss section, 23-first cylindrical section, 24-third boss section, 25-second cylindrical section, 41-limiting step, 42-cylindrical section, 100-first sealing surface, 200-second sealing surface, 300-third sealing surface, 400-fourth sealing surface. Detailed Embodiment

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0028] In a specific embodiment of the present invention, as Figures 1-3 shown, a new type of high differential pressure valve seat sealing structure includes a valve body 1 and a valve seat 2 arranged in the stepped hole of the valve body 1. A sealing gasket 9 is provided between the valve seat 2 and the valve body 1. A sleeve 3 is provided above the valve seat 2. The sleeve 3 is provided with a medium flow through hole, and a valve core 4 is arranged in the sleeve 3;

[0029] The valve seat 2 is provided with a stepped hole. A seal 5 is arranged in the large hole of the valve seat 2. The seal 5 is hollow and a support sleeve 6 is arranged at the stepped hole of the seal 5. The lower end of the support sleeve 6 fits with the inner hole of the valve seat 2 and extends outside the valve seat 2. A locking nut 7 is arranged on the outer side of the lower end of the support sleeve 6. An elastic element 8 is arranged between the locking nut 7 and the valve seat 2. The elastic element 8 is sleeved on the outer side of the support sleeve 6;

[0030] The lower end of the valve core 4 is respectively provided with a first inclined surface and a second inclined surface that cooperate with the upper end surface of the seal 5 and the upper end surface of the support sleeve 6. The upper end surface of the seal 5 and the first inclined surface form a first sealing surface 100. The stepped hole connecting part of the seal 5 and the inclined surface of the support sleeve 6 form a second sealing surface 200. The lower end surface of the seal 5 and the conical surface of the valve seat 2 form a third sealing surface 300. The second inclined surface and the inner hole of the support sleeve 6 form a fourth sealing surface 400.

[0031] Wherein, the inner diameter of the sleeve 3 is greater than the inner diameter of the inner hole of the valve seat 2. The upper end of the valve core 4 is provided with a limit step 41. The limit step 41 contacts the upper end surface of the valve seat 2. The valve core 4 cannot push the support sleeve 6 to further compress the sealing space where the seal 5 is located, so as to achieve the purpose of limiting the highest limit load pressure and ensuring reliable sealing.

[0032] A cylindrical section 42 is arranged between the first inclined surface and the second inclined surface. The diameter of the cylindrical section 42 is greater than the diameter of the small hole of the seal 5 and less than the diameter of the large hole of the seal 5. The seal 5 is made of non-metallic material. A deformation space 10 of the seal 5 is formed among the seal 5, the valve core 4 and the support sleeve 6. When the acting force exceeds the material yield point of the seal 5, the seal 5 can generate plastic deformation in the deformation space 10 to fill the voids and achieve the sealing effect.

[0033] As Figure 3As shown, the lower end of the valve seat 2 includes a first boss section 21, a second boss section 22 and a first cylindrical section 23 which are formed at one time. The sealing gasket 9 is arranged at the first boss section 21. The second boss section 22 fits with the step surface of the valve body 1, thereby improving the sealing effect between the valve seat and the valve body. A gap is provided between the first cylindrical section 23 and the valve body 1, thereby facilitating the installation of the valve seat 2 in the valve body 1.

[0034] The upper end of the valve seat 2 includes a third boss section 24 and a second cylindrical section 25 formed in one step. The outer section of the lower end of the sleeve 3 fits with the third boss section 24, and the inner section fits with the second cylindrical section 25, thereby improving the sealing effect between the sleeve and the valve seat.

[0035] The installation process of the present invention:

[0036] First, install the valve seat 2 in the step hole of the valve body 1 through the sealing gasket 9, and then install the seal 5 in the valve seat 2. The support sleeve 6 is installed at the step hole of the seal 5 from above the seal 5. The elastic element 8 and the locking nut 7 are installed at the lower end of the support sleeve 6. The function of the locking nut 7 is to prevent the seal 5, the support sleeve 6 and the valve seat 2 from falling off. The function of the elastic element 8 is to compensate for the gap caused by the downward movement of the support sleeve 6 after the load; then install the sleeve 3 above the valve seat 2, install the valve core 4 in the sleeve 3, and the valve core 4 moves up and down in the sleeve 3 to realize the opening or closing of the valve.

[0037] The working principle of the present invention is:

[0038] When the valve is closed, the high pressure load force pushes the valve core 4 to move downward along the sleeve 3. When the first inclined surface and the second inclined surface contact the upper end surface of the sealing member 5 and the upper end surface of the support sleeve 6 respectively, the valve seat 2, the valve core 4 and the support sleeve 6 form a compressible sealing space around the sealing member 5.

[0039] When the high-pressure load force is less than the allowable yield force of the seal, the sealing surface of the seal 5 in contact with the valve seat 2, the support sleeve 6, and the valve core 4 produces elastic deformation (or slight plastic deformation), and reliable sealing can be achieved;

[0040] When the high pressure load force is greater than the allowable yield force of the sealing material, since the sealing member 5 is made of non-metallic material and its allowable yield force is relatively low, the cold plastic deformation characteristics of the material are utilized to fill the gap in the sealing space, such as Figure 2As shown, the seal will fill the deformation space. Moreover, as the load force continuously increases, the support sleeve 6 will move downward along the inner hole of the valve seat 2, continuously compressing the sealing space of the seal 5, enabling it to fully fill all the gaps in the sealing space and achieving a zero-leakage sealing effect. The valve seat 2, the valve core 4, and the support sleeve 6 form a compressible sealing space around the seal, and the mating clearance is small enough. The sealing load can increase infinitely. However, in practical applications, since the support sleeve 6 will move downward along the inner hole of the valve seat 2, when the load force reaches a certain limit value, there is a risk that the seal 5 will be extruded from its gap. Therefore, a limiting step 41 is provided on the valve core 4. When the load reaches the designed pressure value, the limiting step 41 contacts the upper end face of the valve seat 2, and the valve core 4 cannot push the support sleeve 6 to continue compressing the sealing space where the seal 5 is located, achieving the purpose of limiting the maximum limit load pressure and ensuring reliable sealing.

[0041] When the valve is opened, the load acting on the seal 5 and the support sleeve 6 is removed. Since the compression deformation generated by the seal 4 cannot be restored to its original state, the gap generated with the support sleeve 6 is compensated by the elastic element 8 to prevent loosening due to compression deformation.

[0042] In the present invention, the sealing space formed by the valve seat, the valve core, and the support sleeve can also be designed into other shape structures, such as trapezoidal, Z-shaped, etc. For the above-mentioned valve seat, valve core, and support sleeve forming the sealing space, appropriate structural adjustments are also required for the relative sealing positions.

[0043] The present invention goes against the traditional soft-sealing structure design. According to the principle of cold plastic deformation of the seal material beyond the yield limit, it fills the voids to achieve a zero-sealing effect. The sealing load it can withstand is several times that of the traditional soft-sealing structure. Moreover, the design structure is simple, the sealing is reliable, and the maintenance is convenient, which can effectively solve the problem of unable to achieve zero-leakage sealing in high-pressure difference load conditions (especially for large-diameter valves).

[0044] The above-disclosed is only a preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A novel high differential pressure valve seat sealing structure, characterized in that, It includes a valve body (1) and a valve seat (2) arranged in the stepped hole of the valve body (1). Above the valve seat (2), there is a sleeve (3). The sleeve (3) is provided with a through hole for medium flow, and a valve core (4) is arranged in the sleeve (3). The valve seat (2) is provided with a stepped hole. A seal (5) is arranged in the large hole of the valve seat (2). The seal (5) is hollow, and a support sleeve (6) is arranged at the stepped hole of the seal (5). The lower end of the support sleeve (6) fits with the inner hole of the valve seat (2) and extends outside the valve seat (2). A locking nut (7) is arranged on the outer side of the lower end of the support sleeve (6). An elastic element (8) is arranged between the locking nut (7) and the valve seat (2). The elastic element (8) is sleeved on the outer side of the support sleeve (6). The lower end of the valve core (4) is respectively provided with a first inclined surface and a second inclined surface that cooperate with the upper end surface of the seal (5) and the upper end surface of the support sleeve (6). A cylindrical section (42) is arranged between the first inclined surface and the second inclined surface. The diameter of the cylindrical section (42) is larger than the diameter of the small hole of the seal (5), and the diameter of the cylindrical section (42) is smaller than the diameter of the large hole of the seal (5). The seal (5) is made of non-metallic material. A deformation space (10) of the seal (5) is formed among the seal (5), the valve core (4), and the support sleeve (6). When the acting force is less than the material yield point of the seal, reliable sealing can be achieved by using the elastic deformation of the seal. When the acting force exceeds the material yield point of the seal, the seal can produce plastic deformation in the deformation space to fill the gap and achieve sealing.

2. The novel high differential pressure valve seat sealing structure according to claim 1, characterized in that, The upper end surface of the seal (5) and the first inclined surface form a first sealing surface (100). The connecting part of the stepped hole of the seal (5) and the inclined surface of the support sleeve (6) form a second sealing surface (200). The lower end surface of the seal (5) and the conical surface of the valve seat (2) form a third sealing surface (300). The second inclined surface and the inner hole of the support sleeve (6) form a fourth sealing surface (400).

3. The novel high differential pressure valve seat sealing structure according to claim 1, characterized in that, The upper end of the valve core (4) is provided with a limit step (41), and the limit step (41) cooperates with the upper end of the valve seat (2).

4. The novel high differential pressure valve seat sealing structure according to claim 1, characterized in that, A sealing gasket (9) is arranged between the valve seat (2) and the valve body (1).

5. The novel high differential pressure valve seat sealing structure according to claim 1, characterized in that, The inner diameter of the sleeve (3) is larger than the inner diameter of the inner hole of the valve seat (2).

6. The novel high differential pressure valve seat sealing structure according to claim 4, characterized in that, The lower end of the valve seat (2) includes a first boss section (21), a second boss section (22), and a first cylindrical section (23) formed integrally. The sealing gasket (9) is arranged at the first boss section (21). The second boss section (22) fits with the stepped surface of the valve body (1). There is a gap between the first cylindrical section (23) and the valve body (1).

7. The novel high differential pressure valve seat sealing structure according to claim 1, characterized in that, The upper end of the valve seat (2) includes a third boss section (24) and a second cylindrical section (25) formed integrally. The outer side section of the lower end of the sleeve (3) fits with the third boss section (24), and the inner side section fits with the second cylindrical section (25).

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