A dual-sealing valve internal structure

Abstract

This application discloses a dual-seal valve internal structure, employing a design that combines a hard metal seal and a soft seal. Upon initial valve closure, the outer valve core first contacts the upper inclined sealing surface of the valve seat, forming the first hard metal seal. Subsequently, the valve stem compresses against the disc spring, causing the soft-seal valve core to move downwards and contact the lower inclined sealing surface of the valve seat, forming the second, near-zero-leakage soft seal. The two seals complement each other. Under low-pressure conditions, the soft seal ensures a Class VI leakage rating. Under high-temperature, high-pressure, or strongly eroded conditions, even if the soft seal experiences some wear, the hard metal seal continues to play a dominant role, thus maintaining a high sealing rating across all operating conditions. The soft-seal valve core is fixed to the bottom of the inner valve core base with fastening bolts, facilitating assembly and replacement. The O-ring effectively blocks the upward leakage of the medium along the gap between the inner valve core base and the outer valve core.

Description

Technical Field

[0001] This invention relates to the field of single-seat sealing valve technology, and more particularly to a double-seat valve internal structure. Background Technology

[0002] In the field of industrial process control, control valves, as key control components in fluid transport systems, directly affect production safety, environmental protection, and energy efficiency through their sealing performance. As modern industry develops towards higher temperatures, higher pressures, stronger corrosion, and higher parameters, increasingly stringent requirements are being placed on the sealing level and service reliability of valves. Currently, the mainstream single-seat valve sealing structures on the market are mainly divided into two categories: pure metal hard seal structures and pure soft seal structures.

[0003] For metal hard-seal structures, the valve core and seat are typically paired using the same or different metal materials, with precise machining and grinding ensuring a tight seal. This type of structure offers advantages such as high temperature resistance, erosion resistance, and high mechanical strength, making it suitable for high-temperature, high-pressure differential, and media containing solid particles. However, due to limitations in the elastic modulus of the metal materials and the microscopic roughness of the machining process, achieving a completely gapless seal between metal sealing pairs is difficult. In practical applications, especially for gaseous or low-viscosity liquid media, relying solely on the metal sealing surface often fails to meet the high leakage levels (such as Class IV and above) specified in standards, resulting in typically significant leakage that cannot satisfy processes with stringent sealing requirements.

[0004] On the other hand, soft-seal structures, by embedding polytetrafluoroethylene (PTFE) in the valve seat or valve core, utilize the elasticity and self-lubricating properties of non-metallic materials to achieve a tight fit under relatively low operating forces, thus achieving a near-zero leakage (Class VI) excellent sealing effect. However, soft-seal materials have inherent limitations: their upper temperature resistance is relatively low, and their material hardness and strength are limited. Under high-pressure conditions, high-speed fluid erosion can easily cause soft seals to be squeezed, deformed, worn, or even torn, thus rapidly losing their sealing function. In addition, pressure fluctuations and frequent operations of the medium can also accelerate the aging and fatigue failure of soft seals, significantly shortening the service life and maintenance cycle of the valve.

[0005] In summary, traditional single-type sealing structures all have corresponding defects. Therefore, there is an urgent need to research and develop a dual-seal valve internal structure that organically combines a metal hard seal and a soft seal structure to improve its applicability and service life under harsh operating conditions. Summary of the Invention

[0006] The purpose of this application is to provide a dual-sealing valve internal structure to solve the defects of traditional single-type sealing structures, thereby improving their applicability and service life under harsh working conditions.

[0007] To address the aforementioned technical problems, this application provides a dual-sealing valve internal structure, comprising: A valve seat is installed on the valve body. An upper valve cover is installed on the upper end of the valve body by bolts. A guide sleeve is inlaid in the lower inner part of the upper valve cover. A valve core assembly is installed in the space formed by the valve seat, the upper valve cover and the guide sleeve. The valve core assembly includes an outer valve core, a first mounting groove is provided at the lower end of the outer valve core, a second mounting groove is provided at the upper end of the outer valve core, an inner valve core base is provided in the first mounting groove, and a soft-seal valve core is fixed to the bottom of the inner valve core base by fastening bolts, the bottom of the fastening bolts abutting against the inner side of the valve seat. A groove is provided on the lower outer periphery of the inner valve core base, and an O-ring is installed in the groove. A valve stem is screwed onto the center of the outer valve core. The lower part of the valve stem is threaded to the inner valve core base, and the upper part of the valve stem passes through the upper valve cover to the outside of the upper valve cover. A disc spring is placed in the second mounting groove and is fitted onto the valve stem. A limiting block is screwed onto the valve stem and abuts against the upper end of the disc spring.

[0008] In a preferred embodiment, a double-sealed valve internal structure is provided, wherein the side of the outer valve core is provided with a mounting hole, and a set screw located on the inner valve core base is installed through the mounting hole, one end of the set screw abutting against one side of the bolt.

[0009] The solution requires further detailed explanation of a double-sealed valve internal structure, in which the limiting block and the valve stem are provided with drilled holes, and cylindrical pins are installed in the drilled holes to prevent the limiting block from rotating.

[0010] In a preferred embodiment, a double-sealed valve internal structure is provided, wherein the inner side of the valve seat is provided with an upper inclined sealing surface and a lower inclined sealing surface with an inclination angle smaller than that of the upper inclined sealing surface, the bottom sealing surface of the outer valve core abuts against the upper inclined sealing surface, and the sealing surface of the soft-sealed valve core abuts against the lower inclined sealing surface.

[0011] The solution requires further detailed explanation of a dual-sealing valve internal structure, wherein the soft-sealing valve core is made of polytetrafluoroethylene or para-polystyrene.

[0012] In a preferred embodiment, a double-sealed valve internal structure has two mounting holes and two set screws.

[0013] Compared with the prior art, the dual-sealing valve internal structure provided by the present invention has at least the following beneficial effects: 1. The internal structure of this dual-seal valve adopts a design that combines metal hard seal and soft seal. When the valve is initially closed, the outer valve core first contacts the upper inclined sealing surface of the valve seat to form the first metal hard seal. Subsequently, the valve stem compresses against the disc spring, causing the soft-seal valve core to move downward and contact the lower inclined sealing surface of the valve seat. The elasticity and plasticity of the non-metallic material of the soft-seal valve core achieve a tight fit, forming the second near-zero leakage soft seal. The two seals complement each other. Under low-pressure conditions, the soft seal ensures a Class VI leakage rating. Under high-temperature, high-pressure, or strong media erosion conditions, even if the soft seal experiences some wear, the metal hard seal can still play a dominant role, thus maintaining a high sealing rating across the entire operating range and solving the problem of poor adaptability of traditional single-seal structures.

[0014] 2. The soft-seal valve core is fixed to the bottom of the inner valve core base with fastening bolts, making assembly and replacement convenient. When the soft seal wears or ages due to long-term use, replacement can be completed simply by removing the fastening bolts, without replacing the entire valve core assembly, significantly reducing maintenance costs and downtime. Simultaneously, the disc spring design maintains a certain elastic compensation stroke between the soft-seal valve core and the valve seat. Even if the soft sealing material experiences minor wear or thermal expansion and contraction, the preload of the disc spring can still push the inner valve core base downwards, automatically compensating for the gap between the sealing pairs and extending the effective service life of the sealing pairs.

[0015] 3. The O-ring is set in the groove on the lower outer periphery of the inner valve core base, forming a sliding seal with the inner wall of the outer valve core. This effectively blocks the upward leakage of the medium along the gap between the inner valve core base and the outer valve core, preventing the medium from entering the valve core assembly and causing corrosion or jamming of the disc spring and threaded connection. Attached Figure Description

[0016] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0017] Figure 1 This is a schematic diagram of a valve core assembly planar structure provided in an embodiment of this application; Figure 2 This is a three-dimensional structural diagram of a valve core assembly provided in an embodiment of this application; Figure 3 This is a schematic diagram of the installation of a double-sealed valve internal structure provided in an embodiment of this application; Figure 4 This is a schematic diagram of a valve seat structure provided in an embodiment of this application; Figure 5This is a schematic diagram of an external valve core structure provided in an embodiment of this application; In the diagram: 1. Fastening bolt; 2. Soft-seal valve core; 3. Inner valve core base; 4. Set screw; 5. Outer valve core; 50. First mounting groove; 51. Second mounting groove; 6. Disc spring; 7. Limiting block; 8. Valve stem; 9. Cylindrical pin; 10. O-ring seal; 11. Valve body; 12. Upper valve cover; 13. Guide sleeve; 14. Valve core assembly; 15. Valve seat; 150. Upper inclined sealing surface; 151. Lower inclined sealing surface. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0019] The core of this application is to provide a dual-sealing valve internal structure that solves the defects of traditional single-type sealing structures, thereby improving their applicability and service life under harsh operating conditions.

[0020] Figure 1 This is a schematic diagram of a valve core assembly planar structure provided in an embodiment of this application. Figure 2 This is a three-dimensional structural diagram of a valve core assembly provided in an embodiment of this application. Figure 3 This is a schematic diagram of the internal structure and installation of a double-sealed valve provided in an embodiment of this application. Figure 4 This is a schematic diagram of a valve seat structure provided in an embodiment of this application. Figure 5 This is a schematic diagram of an external valve core structure provided in an embodiment of this application; see also Figures 1 to 5 As shown.

[0021] Example 1 A double-sealed valve internal structure includes a valve seat 15 mounted on a valve body 11. An upper valve cover 12 is bolted to the upper end of the valve body 11, and a guide sleeve 13 is embedded in the lower inner side of the upper valve cover 12. A valve core assembly 14 is fitted within the space enclosed by the valve seat 15, the upper valve cover 12, and the guide sleeve 13. The guide sleeve 13 provides guiding constraints for the vertical movement of the valve core assembly 14, ensuring the coaxiality of the valve core assembly 14 and the valve seat 15.

[0022] The valve core assembly 14 includes an outer valve core 5. A first mounting groove 50 is provided at the lower end of the outer valve core 5, and a second mounting groove 51 is provided at the upper end of the outer valve core 5. Both the first mounting groove 50 and the second mounting groove 51 are arranged along the length direction of the outer valve core 5. An inner valve core base 3 is disposed within the first mounting groove 50, and a clearance fit is used between the inner valve core base 3 and the first mounting groove 50, allowing the inner valve core base 3 to float axially relative to the outer valve core 5 within a certain range. A soft-seal valve core 2 is fixed to the bottom of the inner valve core base 3 by a fastening bolt 1. In this embodiment, the fastening bolt 1 is arranged along the axial center of the inner valve core base 3. The head of the fastening bolt 1 passes through a through hole on the soft-seal valve core 2 and is embedded inside the inner valve core base 3, and is screwed to a threaded hole on the inner valve core base 3 for fixation. In this embodiment, an upper inclined sealing surface 150 and a lower inclined sealing surface 151 are provided on the inner side of the valve seat 15, wherein the inclination angle of the upper inclined sealing surface 150 is greater than the inclination angle of the lower inclined sealing surface 151. The bottom of the fastening bolt 1 protrudes from the lower end face of the soft-seal valve core 2. When the valve core assembly 14 is initially closed, the lower end metal sealing cone surface of the outer valve core 5 cooperates with the upper inclined sealing surface 150 of the valve seat 15 to form a metal hard seal pair. When the valve core assembly 14 is fully closed, the disc spring 6 pushes the inner valve core base 3 downward, and the sealing surface of the soft-seal valve core 2 abuts against the lower inclined sealing surface 151 to form a soft seal pair.

[0023] A groove is provided on the lower outer periphery of the inner valve core base 3, and an O-ring seal 10 is installed in the groove. The outer diameter of the O-ring seal 10 is slightly larger than the outer diameter of the inner valve core base 3, so that it forms an interference fit with the inner wall of the first mounting groove 50 of the outer valve core 5, thereby achieving a sliding seal between the inner valve core base 3 and the outer valve core 5 and preventing the medium from flowing upward along the gap between the two.

[0024] A valve stem 8 is screwed onto the center of the outer valve core 5. The lower part of the valve stem 8 has an external thread that connects to the threaded hole at the center of the inner valve core base 3. The upper part of the valve stem 8 extends through the central through-hole of the upper valve cover 12 to the outside of the upper valve cover 12 for connection to an external actuator. A disc spring 6 is placed in the second mounting groove, fitted onto the valve stem 8. The lower end of the disc spring 6 abuts against the bottom surface of the second mounting groove 51, and the upper end of the disc spring 6 abuts against the limiting block 7 screwed onto the valve stem 8. The limiting block 7 is threaded onto the valve stem 8. By screwing the limiting block 7, the pre-compression of the disc spring 6 can be adjusted, thereby adjusting the initial sealing pressure of the soft-seal valve core 2.

[0025] Example 2 Based on Embodiment 1, as a preferred embodiment, a double-sealed valve internal structure is provided. The outer valve core 5 has a mounting hole on its side, through which a set screw 4 located on the inner valve core base 3 is installed. One end of the set screw 4 abuts against one side of the fastening bolt 1. The mounting hole is preferably a through hole radially penetrating the side wall of the outer valve core 5. The inner valve core base 3 has a threaded hole. After the set screw 4 is screwed into the threaded hole through the through hole, its inner end abuts against one side of the fastening bolt 1, using friction to prevent the fastening bolt 1 from loosening due to vibration. To further improve the reliability of the anti-loosening mechanism, there are two mounting holes and two set screws 4. One set screw 4 is used to tighten the fastening bolt 1, and the other set screw 4 is used to tighten the valve stem 8.

[0026] As a further preferred embodiment, the limiting block 7 and the valve stem 8 are also provided with drilled holes, and a cylindrical pin 9 is installed in the drilled holes to prevent the limiting block 7 from rotating. Specifically, after the limiting block 7 is screwed to the desired position, a through pin hole is drilled at the junction of the outer circumferential surface of the limiting block 7 and the outer circumferential surface of the valve stem 8, and the cylindrical pin 9 is pressed into the pin hole to achieve circumferential locking between the limiting block 7 and the valve stem 8.

[0027] In this embodiment, the material of the soft-seal valve core 2 is preferably polytetrafluoroethylene (PTFE) or para-polystyrene (PPL). PTFE has excellent self-lubricating properties and corrosion resistance; para-polystyrene has higher hardness and wear resistance. The material selection of the soft-seal valve core 2 is determined according to the actual operating temperature and media corrosivity.

[0028] The dual-sealing valve internal structure provided in this application allows for initial valve closure. When the valve is initially closed, the external actuator drives the valve stem 8 downwards. The valve stem 8 first moves the outer valve core 5 downwards, causing the lower metal sealing cone surface of the outer valve core 5 to tightly adhere to the upper inclined sealing surface 150 of the valve seat 15, forming a first hard metal seal. Subsequently, the valve stem 8 continues to move downwards, compressing the disc spring 6 and causing the inner valve core base 3 and the soft-sealing valve core 2 fixed at its bottom to move downwards until the lower end face of the soft-sealing valve core 2 contacts the lower inclined sealing surface 151 inside the valve seat 15. At this point, utilizing the elastic-plastic deformation of the soft sealing material, a second seal is formed between the soft-sealing valve core 2 and the valve seat 15, achieving a near-zero leakage soft seal effect. At this time, the valve is in a fully closed state, with both the soft seal between the soft-sealing valve core 2 and the valve seat 15 and the hard metal seal between the metal sealing cone surface and the valve seat 15 functioning simultaneously. When the medium is gas or low-viscosity liquid, the soft seal ensures near-zero leakage. When the medium temperature is high, causing a decline in the performance of the soft seal material, or when high pressure differential causes wear on the soft seal surface, the metal hard seal can still maintain a certain sealing effect, ensuring that the overall sealing level of the valve is not lower than Class IV. The two seals are redundant and complementary, significantly improving the sealing reliability of the valve under complex operating conditions.

[0029] When the valve is opened, the external actuator drives the valve stem 8 to move upward. The valve stem 8 first moves the outer valve core 5 upward, causing the metal sealing cone surface to disengage from the valve seat 15. As the valve stem 8 continues to move upward, the limit block 7, through the disc spring 6, moves the inner valve core base 3 upward, causing the soft-seal valve core 2 to disengage from the valve seat 15. At this time, the valve is fully open, and the medium can flow freely through the valve seat 15.

[0030] During valve opening and closing, the O-ring 10 maintains a sliding seal between the inner valve core base 3 and the outer valve core 5, preventing the medium from leaking upwards along the mating gap into the second mounting groove 51 and protecting the disc spring 6 and threaded connection from medium corrosion. The set screw 4 continuously applies a tightening force to the fastening bolt 1 throughout the valve's entire lifespan, preventing the fastening bolt 1 from loosening due to frequent valve operation or medium pressure pulsation, ensuring reliable fixation of the soft-seal valve core 2.

[0031] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and incorporate common knowledge or customary techniques in the art disclosed herein. The specification and examples are to be considered exemplary only, and the true scope of this application is indicated by the claims.

[0032] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The embodiments of this application described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A double-sealed valve internal structure, characterized in that, include: A valve seat (15) is installed on the valve body (11). An upper valve cover (12) is installed on the upper end of the valve body (11) by bolts. A guide sleeve (13) is inlaid on the lower inner side of the upper valve cover (12). A valve core assembly (14) is installed in the space formed by the valve seat (15), the upper valve cover (12) and the guide sleeve (13). The valve core assembly (14) includes an outer valve core (5), the lower end of which is provided with a first mounting groove (50), and the upper end of which is provided with a second mounting groove (51). An inner valve core base (3) is provided in the first mounting groove (50), and a soft-seal valve core (2) is fixed to the bottom of the inner valve core base (3) by a fastening bolt (1). The bottom of the fastening bolt (1) abuts against the inner side of the valve seat (15). A groove is provided on the lower outer periphery of the inner valve core base (3), and an O-ring seal (10) is installed in the groove. A valve stem (8) is screwed on the center of the outer valve core (5). The lower part of the valve stem (8) is threaded to the inner valve core base (3). The upper part of the valve stem (8) passes through the upper valve cover (12) to the outside of the upper valve cover (12). A disc spring (6) is placed in the second mounting groove (51) and is sleeved on the valve stem (8). A limiting block (7) is screwed on the valve stem (8) and abuts against the upper end of the disc spring (6).

2. The internal structure of the double-sealed valve according to claim 1, characterized in that, The outer valve core (5) is also provided with a mounting hole on its side, through which a set screw (4) located on the inner valve core base (3) is installed, and one end of the set screw (4) abuts against one side of the bolt.

3. The internal structure of the double-sealed valve according to claim 1, characterized in that, The limiting block (7) and the valve stem (8) are also provided with drill holes, and a cylindrical pin (9) is installed in the drill holes to prevent the limiting block (7) from rotating.

4. The internal structure of the double-sealed valve according to claim 1, characterized in that, The valve seat (15) is provided with an upper inclined sealing surface (150) and a lower inclined sealing surface (151) with an inclination angle smaller than that of the upper inclined sealing surface (150) on the inner side. The bottom sealing surface of the outer valve core (5) abuts against the upper inclined sealing surface (150), and the sealing surface of the soft sealing valve core (2) abuts against the lower inclined sealing surface (151).

5. The internal structure of the double-sealed valve according to claim 1, characterized in that, The soft-seal valve core (2) is made of polytetrafluoroethylene or para-polystyrene.

6. The internal structure of the double-sealed valve according to claim 2, characterized in that, The number of mounting holes is two, and the number of set screws (4) is two.

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