Clustered seal ball valve with radial auxiliary seal structure
By introducing a radial auxiliary sealing structure into the ball valve, and utilizing the pressure balance chamber and mechanical pre-tightening sealing assembly, the problems of poor sealing and high opening and closing torque in traditional ball valves under high pressure environments are solved, achieving efficient sealing and low-torque opening and closing effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUXI KELK APP & VALVE
- Filing Date
- 2026-05-07
- Publication Date
- 2026-06-09
AI Technical Summary
Traditional ball valves have poor sealing performance in high-demand media environments, require high opening and closing torque, and cannot adapt to asymmetrical pressure environments between upstream and downstream, resulting in resource waste and operational difficulties.
A radial auxiliary sealing structure is adopted, including a pressure balance sealing assembly and a mechanical pre-tightening sealing assembly. Pressure balance chambers and helical springs are integrated in the upstream and downstream valve caps, respectively, to achieve adaptive sealing force adjustment and reduce opening and closing torque.
It achieves ideal high-pressure sealing and low torque, adapts to asymmetrical pressure environments, reduces opening and closing friction, and improves system efficiency.
Smart Images
Figure CN122170243A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of valve technology, and more specifically, to a cartridge-type sealing ball valve with a radial auxiliary sealing structure. Background Technology
[0002] Metal hard-seal ball valves are spherical valves mainly used for controlling fluid media. The main structure consists of valve body, valve body cap, ball, valve stem, valve seat, valve seat sealing ring, and drive mechanism. They are suitable for pipeline systems with high temperature, high pressure, and corrosive media, effectively controlling the operating state of fluid media and improving system efficiency. They are widely used in many fields such as petrochemical, power, metallurgy, urban water supply, and pharmaceutical. Metal hard-seal ball valves require good sealing effect and low opening and closing torque in demanding media environments.
[0003] Currently, the conventional structure of a ball valve generally includes a valve body, a ball core, a valve seat, and sealing structures installed on both sides of the valve seat. The main content of patent number CN117588579B can be referenced. Symmetrical sealing structures are set on both sides of the ball core to achieve pre-tight sealing. However, this ignores the inherent asymmetry of the upstream and downstream pressure environments of the ball valve in actual working conditions. The downstream pressure is usually very low. The downstream valve seat uses a complex structure with the same specifications and cost as the upstream valve seat, resulting in a waste of resources. Furthermore, it cannot be optimized for different pressure requirements of upstream and downstream. In addition, when the valve is closed, the upstream and downstream valve seats are clamped together in the middle with a large force under the preload of spring one. When the valve needs to be opened, the operator must apply a huge torque to overcome the static friction generated by the two spring forces.
[0004] To address the practical problems in existing technologies, a cartridge-type sealing ball valve with a radial auxiliary sealing structure is proposed, aiming to solve the challenges of metal hard-seal ball valves in harsh media environments that require ultra-high performance sealing and low opening and closing torque. Summary of the Invention
[0005] The purpose of this invention is to solve the practical technical problems in the prior art and to provide a cartridge-type sealing ball valve with a radial auxiliary sealing structure.
[0006] The objective of this invention can be achieved through the following technical solution: a cartridge-type sealing ball valve with a radial auxiliary sealing structure, comprising a valve body, a ball core, and a valve stem. Both ends of the valve body can be detachably installed with an upstream valve body cap and a downstream valve body cap that communicate with their interiors. The upstream valve body cap and the downstream valve body cap are respectively installed with a pressure-balanced sealing assembly and a mechanical pre-tightening sealing assembly that are in sealing cooperation with the ball core on the side of the upstream valve body. The pressure balancing sealing assembly includes an upstream guide ring fixedly installed inside the upstream valve cap. A balance piston extending towards the ball core and having the same inner diameter as the ball core through hole is slidably installed on the inner wall of the upstream guide ring. An annular cavity is reserved between the balance piston, the upstream valve cap, and the inner wall of the valve body. An upstream sealing valve seat is embedded in the end of the balance piston near the ball core, sealing the inside of the annular cavity and sealingly fitting with the ball core. An annular protrusion protruding outward and sealingly engaging with the annular cavity is provided in the middle of the outer wall of the balance piston. A butterfly spring is sleeved on the balance piston between the annular protrusion and the upstream sealing valve seat. The outer side of the annular protrusion, the upstream guide ring, and the inner wall of the upstream valve cap form a pressure balancing cavity. Multiple pressure guide holes are annularly opened on the end wall of the upstream guide ring for the flow between the pressure balancing cavity and the upstream valve cap flow channel. The mechanical pre-tightening sealing assembly includes a downstream retaining ring fixedly installed inside the downstream valve body cap, and a downstream sealing valve seat that is sealed to the ball core is fixedly installed on the downstream retaining ring by a mechanical elastic component.
[0007] Furthermore, the valve body has a rotating cavity inside to accommodate the rotating installation of the ball core. The top of the ball core is fitted with an annular weld overlay layer that is movably connected to the top wall of the rotating cavity, and the valve stem is fitted with an upper bearing on the connection surface between the top of the ball core and the valve core.
[0008] Furthermore, the inner wall of the upstream guide ring is provided with multiple sliding grooves, and the outer end wall of the balance piston, which is movably connected to the inner wall of the upstream guide ring, is provided with a sliding strip that is adapted to the sliding groove. The length of the sliding strip is less than the length of the sliding groove.
[0009] Furthermore, a groove is provided on the annular protrusion, and an O-ring seal that is fitted into the groove to seal against the inner wall of the upstream valve cap.
[0010] Furthermore, the downstream fixing ring has a hollow convex structure, which includes a fixing sleeve fixedly installed to the circumferential end wall of the downstream valve body cap and a sliding ring installed at the front end of the fixing sleeve with an outer diameter smaller than that of the fixing sleeve. The inner diameters of the sliding ring and the fixing sleeve are the same.
[0011] Furthermore, the mechanical elastic component includes a sliding sleeve that is slidably mounted on the sliding ring and fixedly connected to the downstream sealing valve seat, and a plurality of helical springs that are fixedly connected to the inner wall of the downstream fixed ring are distributed in a ring on the other end wall of the sliding sleeve.
[0012] Furthermore, the inner diameter of the downstream sealing valve seat is the same as the inner diameter of the sliding ring, and the downstream sealing valve seat and the sliding ring are connected by an elastic sealing sleeve of the same diameter.
[0013] Furthermore, both the upstream and downstream sealing valve seats have annular curved grooves on their inner end faces that are in sealing connection with the spherical surface of the ball core, and a main sealing ring is embedded in each pair of annular curved grooves.
[0014] Compared with the prior art, the advantages of this invention are: 1. This solution involves assembling a pressure-balanced sealing assembly and a mechanical pre-tightening sealing assembly in the upstream and downstream directions of the valve body, respectively, to form an asymmetric, cartridge-type radial sealing structure. This adapts to the inherently asymmetrical pressure environment of the ball valve in actual operating conditions. Specifically, the upstream valve body cap integrates a pressure-balanced chamber, a disc spring, and an adaptive dynamic sealing system for the upstream sealing seat. This allows the upstream pressure balance to adaptively adjust the pre-tightening force of the upstream sealing seat against the ball core during the opening and closing process, thereby reducing the opening and closing torque. The downstream valve body cap integrates a simple spiral spring and a constant sealing system for the downstream sealing seat as a safety redundancy. Under the combined action of medium force and mechanical force, both sealing seats can tightly fit the ball, achieving the ideal effect of high-pressure sealing and low-pressure torque.
[0015] 2. The pressure balance sealing assembly of this solution uses a sealed annular space pressure balance chamber. The upstream medium pressure is transmitted to the sealed pressure balance chamber through a small pressure guide hole, which efficiently and reliably converts the static pressure of the upstream medium into mechanical force. This force acts on the end face of the balance piston, generating a huge thrust to push the butterfly spring. The upstream sealing valve seat is tightly pressed against the surface of the ball by the medium pressure in the pressure balance chamber and the butterfly spring. Through pressure sensing and the nonlinear characteristics of the butterfly spring, dynamic preload adjustment is achieved. That is, when the medium pressure increases, the sealing force automatically increases; when the medium pressure decreases, the sealing force automatically decreases, and the torque also decreases accordingly, thus achieving precise and reliable control of the sealing force. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the external structure of the present invention; Figure 2 This is an exploded view of the present invention; Figure 3 This is an overall cross-sectional view of the invention when it is in conduction. Figure 4 This is a cross-sectional view of the junction between the upstream valve cap and the pressure balance sealing assembly of the present invention. Figure 1 ; Figure 5 This is a cross-sectional view of the junction between the upstream valve cap and the pressure balance sealing assembly of the present invention. Figure 2 ; Figure 6 This is an exploded view of the pressure-balanced sealing assembly of the present invention; Figure 7 This is a cross-sectional view of the pressure-balanced sealing assembly of the present invention; Figure 8 This is a cross-sectional view of the junction between the downstream valve cap and the mechanical pre-tightening sealing assembly of the present invention; Figure 9This is a cross-sectional view of the mechanical pre-tightening sealing assembly of the present invention; Figure 10 This is an overall cross-sectional view of the present invention; Figure 11 This is a cross-sectional view of the invention when closed. Figure 1 ; Figure 12 This is a cross-sectional view of the invention when closed. Figure 2 .
[0017] Explanation of the labels in the diagram: 1. Valve body; 2. Ball core; 3. Valve stem; 4. Upstream valve body cap; 5. Downstream valve body cap; 6. Upstream guide ring; 601. Pressure guide hole; 602. Slide groove; 7. Balance piston; 701. Slide bar; 8. O-ring seal; 9. Upstream sealing valve seat; 10. Butterfly spring; 11. Pressure balance chamber; 12. Annular weld overlay; 13. Downstream retaining ring; 14. Downstream sealing seat; 15. Sliding sleeve; 16. Elastic sealing sleeve; 17. Helical spring. Detailed Implementation
[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0019] Example 1: To address the issue that the valve ball's completely symmetrical sealing structure design on both upstream and downstream sides is difficult to adapt to the asymmetrical pressure environment in actual operating conditions, the following technical solution is proposed: For cartridge-type sealed ball valves with radial auxiliary sealing structure, please refer to [link / reference]. Figures 1-3 The valve body includes a valve body 1, a ball core 2, and a valve stem 3. The valve body 1 has a rotating cavity inside to accommodate the rotating installation of the ball core 2. The top of the ball core 2 is fitted with an annular weld overlay layer 12 that is movably connected to the top wall of the rotating cavity. The valve stem 3 is fitted with an upper bearing on the top connection surface of the ball core 2.
[0020] Both ends of the valve body 1 can be detachably installed with an upstream valve body cap 4 and a downstream valve body cap 5 that are connected to the interior. The upstream valve body cap 4 and the downstream valve body cap 5 are respectively installed with a pressure balance sealing assembly and a mechanical pre-tightening sealing assembly that are in sealing cooperation with the ball core 2 on the side close to the valve body 1.
[0021] Please see Figures 3-7The pressure balance sealing assembly includes an upstream guide ring 6 fixedly installed inside the upstream valve body cap 4. A balance piston 7 extending toward the ball core 2 and having the same size as the inner diameter of the through hole of the ball core 2 is slidably installed on the inner wall of the upstream guide ring 6. A plurality of sliding grooves 602 are circumferentially opened on the inner wall of the upstream guide ring 6. A sliding strip 701 adapted to the sliding groove 602 is circumferentially installed on the outer end wall of the balance piston 7 that is movably connected to the inner wall of the upstream guide ring 6. The length of the sliding strip 701 is less than the length of the sliding groove 602. An annular cavity is reserved between the balance piston 7, the upstream valve cap 4, and the inner wall of the valve body 1. An upstream sealing valve seat 9 is installed at the end of the balance piston 7 near the ball core 2, which is sealed inside the annular cavity and is in a sealed fit with the ball core 2. An annular protrusion is provided in the middle of the outer wall of the balance piston 7, which protrudes outward and is sealed to the annular cavity. A butterfly spring 10 is provided between the inner side of the annular protrusion and the upstream sealing valve seat 9 and is sleeved on the balance piston 7. The outer side of the annular protrusion and the upstream guide ring 6 and the inner wall of the upstream valve cap 4 form a pressure balance cavity. A plurality of pressure guide holes 601 are opened in the annular shape on the end wall of the upstream guide ring 6 for the flow between the pressure balance cavity and the flow channel of the upstream valve cap 4. A groove is provided on the annular protrusion, and an O-ring 8 is embedded in the groove to seal against the inner wall of the upstream valve cap 4. The O-ring 8 is made of a medium-compatible and high-temperature resistant elastic material, such as fluororubber or perfluoroether rubber, for harsh working conditions. The O-ring 8 and the inner wall of the upstream valve cap 4 form an absolute static seal to block the "rear end" of the pressure balance chamber 11 and prevent the medium in the chamber from leaking backward along the fit gap between the balance piston 7 and the upstream valve cap 4. The pressure balancing chamber 11 is a sealed space formed by the inner wall of the valve body, the pressure-bearing side of the back of the balancing piston, and the O-ring seal 8. In the closed state, the upstream medium enters the pressure balancing chamber 11 through the pressure guide hole 601. Under the thrust of the pressure balancing chamber 11, the balancing piston 7 is pushed backward, and the butterfly spring 10 is radially compressed, generating elastic force. This thrust acts directly on the upstream sealing valve seat 9 through the butterfly spring 10. The upstream sealing valve seat 9 is pressed tightly on the surface of the ball core 2, forming a metal-soft seal secondary sealing structure, which enhances the initial sealing pressure of the upstream sealing valve seat 9 on the ball core 2. This barrier blocks the "front end" of the pressure balancing chamber 11, isolating it from the ball core through hole or the downstream channel of the valve. In the open state, when the ball core 2 rotates away from the valve seat, the medium pressure decreases. The rebound force of the radially assisted compression butterfly spring 10 helps the valve seat to instantly retract radially and disengage from the surface of the ball core 2, thereby greatly reducing rotational friction and torque. Note: The retraction range of the butterfly spring 10 will not cause the upstream sealing valve seat 9 to disengage from the surface of the ball core 2 by too much distance. Through the coordinated operation of the pressure balance chamber 11 and the butterfly spring 10, the ball valve can adaptively adjust the preload force of the upstream sealing valve seat 9 pressing against the ball core 2 during the opening and closing process. That is, when the system pressure increases, the sealing force automatically increases, and when the system pressure decreases, the sealing force automatically decreases, and the torque also decreases accordingly.
[0022] Please see Figure 3 and Figures 8-9 The mechanical pre-tightening sealing assembly includes a downstream fixing ring 13 fixedly installed inside the downstream valve body cap 5. A downstream sealing valve seat 14 that is sealed and fitted to the ball core 2 is fixedly installed on the downstream fixing ring 13 by a mechanical elastic component. The downstream fixing ring 13 has a hollow convex structure and includes a fixing sleeve fixedly installed to the circumferential end wall of the downstream valve body cap 5 and a sliding ring installed at the front end of the fixing sleeve with an outer diameter smaller than the fixing sleeve. The inner diameters of the sliding ring and the fixing sleeve are the same.
[0023] The mechanical elastic component includes a sliding sleeve 15 that is slidably mounted on the sliding ring and fixedly connected to the downstream sealing valve seat 14. Multiple helical springs 17 that are fixedly connected to the inner wall of the downstream fixed ring 13 are distributed in a ring on the other end wall of the sliding sleeve 15. The inner diameter of the downstream sealing valve seat 14 is the same as the inner diameter of the sliding ring, and the downstream sealing valve seat 14 and the sliding ring are connected by an elastic sealing sleeve 16 of the same diameter.
[0024] The initial preload of the upstream butterfly spring 10 and the preload of the downstream mechanical spring must be in a delicate balance: the initial preload of the upstream should be slightly less than the preload of the downstream. In this way, at the moment of opening, after the upstream high pressure is released, the downstream thrust will become dominant, gently pushing the ball core 2 towards the upstream side, ensuring that the upstream sealing valve seat 9 and the downstream sealing valve seat 14 are always in contact with the end face of the ball core 2.
[0025] Please see Figure 10 The upstream sealing valve seat 9 and the downstream sealing valve seat 14 are provided with annular curved grooves on their inner end faces to seal with the spherical surface of the ball core 2. A main sealing ring is embedded in each pair of annular curved grooves. The surface of the upstream valve body cap 4 corresponding to the main sealing ring is polished or hard chrome plated to reduce the friction coefficient and improve wear resistance and corrosion resistance.
[0026] Please see Figure 3 and Figures 10-12 The pressure-balanced sealing assembly and the mechanical pre-tightening sealing assembly are pre-assembled inside the upstream valve body cap 4 and the downstream valve body cap 5, respectively. Then, the upstream valve body cap 4 and the downstream valve body cap 5 are fixedly installed to the left and right ports of the valve body 1 through flanges, which adapts to the pressure environment of the ball valve under actual working conditions due to the asymmetry between the upstream and downstream sides. Specifically: The upstream valve body cap 4 integrates a pressure balance chamber, a disc spring, and an adaptive dynamic sealing system for the upstream sealing valve seat. This allows the upstream sealing valve seat 9 to adaptively adjust the preload on the ball core 2 during the opening and closing process, thereby reducing the opening and closing torque. The downstream valve body cap 5 integrates a simple spiral spring and a constant sealing system for the downstream sealing valve seat. As a safety redundancy, under the combined action of medium force and mechanical force, both sealing valve seats can tightly fit the ball, achieving the ideal effect of high-pressure sealing and low-pressure torque.
[0027] In summary: Pressure balancing sealing assemblies and mechanical pre-tightening sealing assemblies are respectively assembled in the upstream and downstream directions of valve body 1, forming an asymmetric cartridge radial sealing structure. This structure adapts to the pressure environment of the ball valve in actual working conditions, which is inherently asymmetrical between the upstream and downstream. Specifically, the upstream valve body cap 4 integrates a pressure balancing chamber, a disc spring, and an adaptive dynamic sealing system for the upstream sealing seat. This allows the upstream sealing seat 9 to adaptively adjust the pre-tightening force against the ball core 2 during the opening and closing of the ball valve based on the upstream pressure balance. The downstream valve body cap 5 integrates a simple spiral spring and a constant sealing system for the downstream sealing seat. The upstream system can adaptively adjust with pressure, while the downstream system serves as a safety redundancy. Together, they achieve the ideal effect of high-pressure sealing and low-pressure torque.
[0028] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto; any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.
Claims
1. A cartridge-type sealing ball valve with a radial auxiliary sealing structure, comprising a valve body (1), a ball core (2), a valve stem (3), and an upstream valve body cap (4) and a downstream valve body cap (5) installed upstream and downstream of the valve body (1), characterized in that: The upstream valve cap (4) and the downstream valve cap (5) are respectively equipped with a pressure balance sealing assembly and a mechanical pre-tightening sealing assembly that are in sealing fit with the ball core (2) on the side near the valve body (1); The pressure balancing sealing assembly includes an upstream guide ring (6) fixedly installed inside the upstream valve cap (4) and a balance piston (7) slidably installed thereon. An annular cavity is reserved between the balance piston (7) and the assembled upstream valve cap (4) and the inner wall of the valve body (1). An upstream sealing valve seat (9) that is sealed and fitted with the ball core (2) is embedded in the inner end of the balance piston (7). An annular protrusion that is sealed and connected with the annular cavity is provided in the middle of the outer wall of the balance piston (7). A butterfly spring (10) located between the annular protrusion and the upstream sealing valve seat (9) is sleeved on the balance piston (7). The outer side of the annular protrusion and the upstream guide ring (6) and the inner wall of the upstream valve cap (4) form a pressure balancing cavity. A plurality of pressure guide holes (601) leading to the pressure balancing cavity are opened in an annular shape on the end wall of the upstream guide ring (6). The mechanical pre-tightening sealing assembly includes a downstream fixing ring (13) fixedly installed inside the downstream valve body cap (5), and a downstream sealing valve seat (14) that is sealed and fitted with the ball core (2) is fixedly installed on the downstream fixing ring (13) by a mechanical elastic component.
2. The cartridge-type sealing ball valve with radial auxiliary sealing structure according to claim 1, characterized in that: The valve body (1) has a rotating cavity inside to accommodate the rotating installation of the ball core (2). The top of the ball core (2) is fitted with an annular weld overlay layer (12) that is movably connected to the top wall of the rotating cavity. The valve stem (3) and the top surface of the ball core (2) are fitted with an upper bearing.
3. The cartridge-type sealing ball valve with radial auxiliary sealing structure according to claim 1, characterized in that: The inner wall of the upstream guide ring (6) is provided with a plurality of sliding grooves (602). The outer end wall of the balance piston (7) that is movably connected to the inner wall of the upstream guide ring (6) is provided with a sliding strip (701) that is adapted to the sliding groove (602). The length of the sliding strip (701) is less than the length of the sliding groove (602).
4. The cartridge-type sealing ball valve with radial auxiliary sealing structure according to claim 1, characterized in that: The annular protrusion has a groove, and an O-ring (8) is embedded in the groove to seal against the inner wall of the upstream valve cap (4).
5. The cartridge-type sealing ball valve with radial auxiliary sealing structure according to claim 1, characterized in that: The downstream fixed ring (13) has a hollow convex structure, which includes a fixed sleeve that is fixedly installed with the circumferential end wall of the downstream valve body cap (5) and a sliding ring installed at the front end of the fixed sleeve with an outer diameter smaller than the fixed sleeve. The inner diameters of the sliding ring and the fixed sleeve are the same.
6. The cartridge-type sealing ball valve with radial auxiliary sealing structure according to claim 5, characterized in that: The mechanical elastic component includes a sliding sleeve (15) that is slidably mounted on a sliding ring and fixedly connected to a downstream sealing valve seat (14). The other end wall of the sliding sleeve (15) is circumferentially distributed with a plurality of helical springs (17) that are fixedly connected to the inner wall of the downstream fixed ring (13).
7. The cartridge-type sealing ball valve with radial auxiliary sealing structure according to claim 6, characterized in that: The inner diameter of the downstream sealing valve seat (14) is the same as the inner diameter of the sliding ring, and the downstream sealing valve seat (14) and the sliding ring are connected by an elastic sealing sleeve (16) of the same diameter.
8. The cartridge-type sealing ball valve with radial auxiliary sealing structure according to claim 1, characterized in that: The upstream sealing valve seat (9) and the downstream sealing valve seat (14) are provided with annular curved grooves on their inner end faces that are in sealing connection with the spherical surface of the ball core (2), and a main sealing ring is embedded in each pair of annular curved grooves.