A valve assembly

Abstract

This invention relates to the field of fluid control valve technology. The invention discloses a valve assembly including a valve body, a front return spring, a front limiting concave ring, a connector, a limiting ball, an abutment, a rear limiting concave ring, and a rear return spring. The valve body has an axially penetrating valve body through-hole. The front return spring abuts against the valve body and the front limiting concave ring, which has a front central through-hole and a front side through-hole. The connector is located on one side of the front limiting concave ring and has a central through-hole and a side through-hole, which are sealed by the limiting ball. The abutment presses the limiting ball through a spherical limiting groove, and its central protrusion cooperates with the annular abutment platform to release the rear return spring. The rear limiting concave ring has a rear central through-hole and limits the spring to prevent it from dislodging. Without electrical control, it can automatically switch flow paths according to fluid pressure, providing forward flow and preventing backflow. The annular abutment platform and central protrusion protect the spring, and the front side through-hole reduces fluid impact, integrating dual functions and simplifying pipelines.

Description

Technical Field

[0001] This invention relates to the field of fluid control valve technology, and more particularly to a valve assembly. Background Technology

[0002] In fluid transportation, water supply and drainage engineering, hydraulic and pneumatic systems, and industrial pipeline control, valve assemblies are indispensable core control components. Their main functions are to realize fluid flow control, flow direction regulation, and pressure stabilization, directly affecting the operating efficiency and safety performance of the entire pipeline system. Currently, there are many types of valve products on the market, but most suffer from unreasonable structural design and limited functionality, making it difficult to meet the requirements of modern pipeline systems for integration, high stability, and long service life. Conventional check valves can only achieve fluid conduction in one direction and cannot achieve reverse controllable backflow and pressure relief; while dedicated pressure relief valves require additional check valves, which not only increases the complexity of pipeline assembly but also increases equipment costs and installation space requirements. At the same time, the use of multiple valves together is prone to connection failures, affecting the overall system's operational stability. In addition, the return springs inside existing valves often lack effective limiting and restraining structures. During long-term reciprocating extension and retraction, they are prone to radial displacement, disengagement, or bending deformation, leading to valve core jamming and untimely reset, which in turn causes fluid leakage, abnormal pipeline pressure, and other problems, and in severe cases, even damage to the entire pipeline system.

[0003] Meanwhile, the core components of traditional valves often lack targeted anti-corrosion and wear-resistant designs. In complex fluid media environments such as acids, alkalis, and high temperatures, they are prone to rust, wear, and aging, significantly shortening their service life and increasing the frequency and cost of subsequent maintenance. Regarding sealing performance, existing valves often employ planar contact or simple spherical contact designs, resulting in insufficient sealing and easy fluid leakage, affecting the sealing and safety of the pipeline system. Furthermore, some valves have unreasonable flow channel orifice layouts, easily causing localized excessively high flow velocities and uneven pressure during fluid passage. This not only causes significant fluid impact and exacerbates wear on internal components but also generates noticeable operating noise and increases energy consumption. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention discloses a valve assembly with a reasonable structure, integrated functions, and stable performance.

[0005] This invention discloses a valve assembly comprising:

[0006] Valve body, front return spring, front limit concave ring, connector, limit ball, abutment, rear limit concave ring and rear return spring;

[0007] The valve body is hollow inside and has a through hole along the axial direction that passes through both sides.

[0008] The front return spring is located inside the valve body, with one end abutting against the inner wall of the valve body through hole;

[0009] The front limiting concave ring has an inward concave ring structure. The other end of the front return spring abuts against the inward concave side of the front limiting concave ring. A through-hole is provided at the bottom of the inward concave of the front limiting concave ring. Several front side through holes are provided on the side wall of the front limiting concave ring.

[0010] The connector is fixedly installed on the side of the front limiting concave ring away from the valve body through hole. The connector has a central through hole in the middle that is connected to the front central through hole. The central through hole of the connector has several side through holes in the circumference of the connector. The side through holes of the connector are blocked by the front limiting concave ring.

[0011] The limiting ball is located on the side of the connector away from the front limiting recess ring and blocks the central through hole of the connector;

[0012] The abutment is recessed on the side facing the limiting ball to form a spherical limiting groove for limiting the limiting ball. The abutment abuts against the limiting ball through the spherical limiting groove, keeping the limiting ball in a state of blocking the central through hole of the connector. The abutment is provided with a central protrusion on the side away from the limiting ball. The central protrusion extends into the interior of the return spring. The abutment extends outward from the outer periphery of the side facing the limiting ball to form an annular abutment platform. The annular abutment platform abuts against one end of the return spring.

[0013] The rear limiting concave ring has an inward concave ring structure. A through-hole is provided at the bottom of the concave rear limiting concave ring. The end of the rear return spring away from the abutment extends into the concave cavity of the rear limiting concave ring and is limited to prevent the rear limiting concave ring from coming out of the valve body through hole.

[0014] Furthermore, the diameter of the spherical limiting groove is smaller than the diameter of the limiting ball, and the bottom radius of the spherical limiting groove matches the radius of the limiting ball.

[0015] Furthermore, the surfaces of the valve body, front return spring, rear return spring, limit ball, and abutment are all coated with anti-corrosion coatings or made of stainless steel.

[0016] Furthermore, several front side through holes are evenly distributed along the circumferential direction of the side wall of the front limiting concave ring, and the front side through holes are circular through holes or waist-shaped through holes.

[0017] Furthermore, the outer peripheral wall of the rear limiting recess ring is provided with a wear-resistant coating, which is a polytetrafluoroethylene coating or a ceramic coating.

[0018] Furthermore, the annular abutment platform has an annular positioning groove on the side facing the rear return spring, and the end of the rear return spring is embedded in the annular positioning groove; the end of the central protrusion has a chamfer or rounded corner.

[0019] Beneficial effects:

[0020] This valve assembly integrates the dual core functions of forward conduction and reverse pressure relief and return flow, eliminating the need for additional electrical control equipment or auxiliary valves. It achieves automated flow channel control, significantly improving ease of use and pipeline integration. During forward flow, fluid pressure directly pushes the front limiting concave ring to compress the front return spring, creating a flow gap between the side through-hole of the connector and the front limiting concave ring. The fluid flows smoothly out through the front side through-hole, the front center through-hole, and the end of the front limiting concave ring. The front side through-holes are evenly distributed circumferentially along the side wall and are designed as circular or oblong through-holes, ensuring smooth fluid flow and balanced force, avoiding fluid impact and component wear caused by excessive local flow velocity, and reducing valve operating noise. During reverse flow or backflow, fluid pressure drives the front limiting concave ring to move towards the connector, automatically sealing the side through-hole of the connector, forcing the fluid to flow only through the center through-hole of the connector and act on the limiting ball. When the fluid pressure exceeds the threshold, it pushes the limiting ball to move, opening the flow channel corresponding to the rear return spring, achieving directional pressure relief and backflow, effectively avoiding the impact of disordered backflow on the pipeline system, and ensuring the directionality and stability of valve operation. Overall, the valve assembly, through structural optimization and functional integration, eliminates the need for complex external drive devices and achieves automatic flow channel switching solely based on fluid pressure. It is highly responsive and easy to operate, while also simplifying the overall pipeline structure and reducing the complexity of system installation and maintenance. It is suitable for various scenarios such as water supply and drainage pipelines, hydraulic and pneumatic pipelines, and fluid transportation systems, and has broad application and promotion value and a promising market prospect. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a valve assembly in one embodiment of this application.

[0022] Figure 2 This is a cross-sectional structural diagram of a valve assembly in an embodiment of this application.

[0023] Figure 3 This is a schematic diagram of another cross-sectional structure of the valve assembly in the embodiments of this application.

[0024] In the figure: valve assembly 100, valve body 11, front return spring 12, front limit concave ring 13, connector 14, limit ball 15, abutment 16, central protrusion 161, annular abutment platform 162, rear limit concave ring 17, rear return spring 18. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions in the specific embodiments of the present invention will be clearly and completely described below.

[0026] This invention discloses a valve assembly 100, such as Figure 1 and Figure 2 It is shown to include:

[0027] Valve body 11, front return spring 12, front limit concave ring 13, connecting piece 14, limit ball 15, abutment piece 16, rear limit concave ring 17 and rear return spring 18;

[0028] The valve body 11 is hollow inside and has a through hole that passes through both sides along the axial direction.

[0029] like Figure 3 As shown, the front return spring 12 is disposed inside the valve body 11, with one end abutting against the inner wall of the through hole of the valve body 11;

[0030] The front limiting concave ring 13 has an inward concave ring structure. The other end of the front return spring 12 abuts against the inward concave side of the front limiting concave ring 13. A through-hole is provided at the bottom of the inward concave part of the front limiting concave ring 13. Several front side through holes are provided on the side wall of the front limiting concave ring 13.

[0031] The connector 14 is fixedly installed on the side of the front limiting concave ring 13 away from the through hole of the valve body 11. The connector 14 has a central through hole in the middle that is connected to the front central through hole. The central through hole of the connector 14 has several side through holes in the circumferential direction. The side through holes of the connector 14 are blocked by the front limiting concave ring 13.

[0032] The limiting ball 15 is located on the side of the connector 14 away from the front limiting recess 13, and blocks the central through hole of the connector 14;

[0033] The abutment member 16 is recessed on the side facing the limiting ball 15 to form a spherical limiting groove for limiting the limiting ball 15. The abutment member 16 abuts against the limiting ball 15 through the spherical limiting groove, keeping the limiting ball 15 in a state of blocking the central through hole of the connector 14. The abutment member 16 has a central protrusion 161 on the side away from the limiting ball 15. The central protrusion 161 extends into the interior of the return spring 18. The outer periphery of the abutment member 16 facing the limiting ball 15 extends outward to form an annular abutment platform 162. Figure 3 As shown, the annular abutment platform 162 gradually moves away from the connector 14 from the direction close to the limiting ball 15 to the direction away from the limiting ball 15. At this time, the annular abutment platform 162 will not block the side through hole of the connector 14, and the liquid can flow through the side through hole of the connector 14. After the annular abutment platform 162 abuts against one end of the reset spring 18.

[0034] The rear limiting concave ring 17 has an inwardly concave ring structure. A through rear central through hole is provided at the bottom of the concave concave concave ring 17. The end of the rear return spring 18 away from the abutment member 16 extends into the concave cavity of the rear limiting concave ring 17 and is limited to prevent the rear limiting concave ring 17 from coming out of the through hole of the valve body 11.

[0035] The operation of this valve assembly 100 is as follows: liquid enters the valve assembly 100 through the rear center through hole on one side of the rear limiting concave ring 17, and then flows through the connecting member 14 through the side through hole. At this time, the liquid puts pressure on the front limiting concave ring 13, which in turn transmits pressure to the front return spring 12. When the pressure is large enough, the front return spring 12 is compressed. At this time, the front limiting concave ring 13 begins to move away from the connecting member 14, and the liquid begins to flow out from the front center through hole of the front limiting concave ring 13 and into the front limiting concave ring 13. Then, the liquid flows out from the end of the front limiting concave ring 13 away from the front center through hole and several front side through holes, and finally flows out from the through hole of the valve body 11 near the front return spring 12.

[0036] Another usage procedure of this valve assembly 100 is as follows: liquid flows in or back from the through hole of the valve body 11 near the front return spring 12. When the pressure of the inflow or return reaches a certain level, the pressure of the liquid drives the front limiting concave ring 13 to move towards the connector 14 until it abuts against the connector 14. At this time, the through holes on the side of the connector 14 are blocked by the front limiting concave ring 13 and the connector 14. The liquid can only flow through the central through hole of the connector 14, thereby applying pressure to the limiting ball 15. When the applied pressure is greater than the water flow pressure on the side of the rear limiting concave ring 17 and the elastic force of the rear return spring 18, the rear return spring 18 is compressed. At this time, the limiting ball 15 moves away from the connector 14, and the liquid flows from the central through hole of the connector 14 into the rear limiting concave ring 17 and then flows out of the valve assembly 100 through the rear central through hole on the side of the rear limiting concave ring 17.

[0037] The valve assembly 100 has a compact and robust overall structure. The front limiting concave ring 13 and the rear limiting concave ring 17 provide reliable limiting constraints for the front return spring 12 and the rear return spring 18, respectively, effectively preventing the springs and related components from coming out of the through hole in the valve body 11 and ensuring overall stability after assembly. The front return spring 12 and the rear return spring 18 provide stable return support for the front limiting concave ring 13 and the limiting ball 15, respectively, so that each moving part can quickly return to its original position after changes in fluid pressure, ensuring continuous and stable valve operation. At the same time, the limiting ball 15 and the spherical limiting groove of the abutment part 16 fit tightly together, providing excellent sealing performance. In the non-working state, it can effectively seal the central through hole of the connecting part 14 and prevent fluid leakage.

[0038] This valve can automatically open and close and switch flow channels according to the fluid pressure, without the need for external electrical control. It has a sensitive pressure response and is easy to use. During forward flow, the fluid pressure pushes the front limit ring 13 to compress the front return spring 12, opening the flow channel to allow the fluid to flow smoothly. During reverse fluid backflow, the fluid pressure drives the front limit ring 13 to block the side through hole of the connector 14, forcing the fluid to flow only through the center through hole of the connector 14, realizing directional flow channel switching, effectively avoiding disorderly fluid backflow, and ensuring the directional operation of the valve and the stability of pipeline operation.

[0039] The annular abutment platform 162 and the central protrusion 161 on the abutment member 16 are reasonably designed. The annular abutment platform 162 can stably abut and support the rear return spring 18 without blocking the side through hole of the connector 14, ensuring normal fluid flow. At the same time, the central protrusion 161 can radially limit the rear return spring 18 to prevent the spring from shifting or bending, reducing component wear. The multiple front side through holes opened in the front limiting concave ring 13 can make the fluid flow out evenly, reducing fluid impact and working noise. The valve integrates the dual functions of forward conduction and reverse pressure relief and return flow, eliminating the need for additional auxiliary valves, simplifying the pipeline structure, and improving the valve's applicability and service life.

[0040] In one implementation, the diameter of the spherical limiting groove is smaller than the diameter of the limiting ball 15, and the bottom radius of the spherical limiting groove matches the radius of the limiting ball 15.

[0041] The diameter of the spherical limiting groove is smaller than the diameter of the limiting ball 15, which can reliably limit the limiting ball 15 and prevent it from falling out of the groove, ensuring the stability of the component fit; and the bottom radius of the groove matches the radius of the limiting ball 15, which can make the two fit tightly, improve the sealing effect, effectively prevent fluid leakage from the central through hole of the connector 14, and at the same time, it does not affect the flexible movement of the limiting ball 15 under pressure, ensuring the stable and smooth realization of the valve's reverse pressure relief and backflow function.

[0042] In one embodiment, the surfaces of the valve body 11, the front return spring 12, the rear return spring 18, the limit ball 15, and the abutment member 16 are all provided with an anti-corrosion coating or are made of stainless steel.

[0043] The valve body 11, return spring, limit ball 15 and abutment part 16 and other components are made of stainless steel or have anti-corrosion coating, which can effectively resist the corrosion and erosion of fluids, prevent the components from rusting, wearing or failing, improve the overall corrosion resistance and service life of the valve, and ensure that the valve can work stably in different media environments, reduce the frequency of maintenance, and enhance the applicable scenarios and long-term reliability of the valve.

[0044] In one embodiment, a number of front side through holes are evenly distributed along the circumferential direction of the side wall of the front limiting recess 13, and the front side through holes are circular through holes or waist-shaped through holes.

[0045] The through holes on the front side are evenly distributed around the circumference of the side wall, which can make the fluid flow evenly and smoothly when it flows out, avoiding the situation of excessive local flow velocity or excessive impact. The structure of the circular or waist-shaped through holes is easy to process and smooth flow. It can ensure sufficient flow area and is not easy to be blocked by impurities, effectively improving the flow efficiency and working stability of the valve.

[0046] As one embodiment, the outer peripheral wall of the rear limiting recess 17 is provided with a wear-resistant coating, which is a polytetrafluoroethylene coating or a ceramic coating.

[0047] The outer peripheral wall of the rear limiting concave ring 17 is coated with polytetrafluoroethylene or ceramic wear-resistant coating, which can effectively reduce the frictional resistance between it and the inner wall of the through hole of the valve body 11, reduce wear and jamming caused by long-term reciprocating motion, and improve the smoothness of component movement; at the same time, it can extend the service life of the rear limiting concave ring 17, enhance the durability and working stability of the overall valve structure, and ensure that the valve can maintain reliable limiting and sealing effects during long-term use.

[0048] In one embodiment, the annular abutment platform 162 has an annular positioning groove on the side facing the rear return spring 18, and the end of the rear return spring 18 is embedded in the annular positioning groove; the end of the central protrusion 161 has a chamfer or rounded corner.

[0049] The annular abutment platform 162 is provided with an annular positioning groove to securely embed the end of the rear reset spring 18, preventing the spring from radially shifting or falling off during the extension and retraction process, ensuring that the spring is subjected to uniform force and moves stably; the chamfer or rounded corner at the end of the central protrusion 161 can reduce assembly resistance, prevent scratching the inner wall of the spring during assembly, and at the same time reduce frictional loss during movement, improving the overall assembly convenience and operational reliability of the valve.

[0050] In one embodiment, the inner depth of the front limiting concave ring 13 is greater than the compression stroke of the front return spring 12, and the inner depth of the rear limiting concave ring 17 is greater than the compression stroke of the rear return spring 18.

[0051] like Figure 2 and Figure 3As shown, the front limiting concave ring 13 has an inwardly concave annular structure, and its concave cavity is used to accommodate the end of the front return spring 12. The concave depth H1 of the front limiting concave ring 13 is designed to be greater than the maximum compression stroke L1 of the front return spring 12. When the front return spring 12 is compressed under fluid pressure, its compression deformation can reach a maximum of L1. Since H1>L1, the end of the front return spring 12 is always constrained within the concave cavity of the front limiting concave ring 13 and will not come out from its side wall. Similarly, the rear limiting concave ring 17 has an inwardly concave annular structure, and its concave depth H2 is greater than the maximum compression stroke L2 of the rear return spring 18. When the limiting ball 15 pushes the abutment member 16 to compress the rear return spring 18, the end of the rear return spring 18 is also confined within the concave cavity of the rear limiting concave ring 17. The front limiting concave ring 13 and the rear limiting concave ring 17 form a double limit in the radial and axial directions for the front return spring 12 and the rear return spring 18, respectively, effectively preventing the spring from radially shifting, bending, deforming, or coming out of the through hole of the valve body 11 during the extension and retraction movement.

[0052] The front limiting concave ring 13 and the rear limiting concave ring 17 provide reliable constraint and limitation for the front return spring 12 and the rear return spring 18, respectively, preventing the springs from dislodging, jamming, or skewing during long-term reciprocating extension and retraction, thus improving the operational stability and reset reliability of the valve's moving parts. Since the springs are always confined within a predetermined movement trajectory, the opening and closing position accuracy of the connecting piece 14 is guaranteed, thereby reducing the risk of fluid leakage caused by spring misalignment. This structure reduces frictional contact between the springs and the inner wall of the valve body 11, reducing component wear and extending the overall service life of the valve assembly.

[0053] In one implementation, the ratio of the diameter of the limiting ball 15 to the diameter of the central through hole of the connector is 1.2:1 to 1.5:1, so that the limiting ball 15 forms an annular line contact seal when blocking the central through hole of the connector.

[0054] like Figure 2 and Figure 3As shown, the limiting ball 15 is located on the side of the connector 14 away from the front limiting recess 13 and is used to block the central through hole of the connector 14. The ratio of the diameter D of the limiting ball 15 to the diameter d of the central through hole of the connector is set to 1.2:1 to 1.5:1. Within this ratio range, the spherical surface of the limiting ball 15 forms an annular line contact seal with the edge of the central through hole of the connector, rather than a traditional surface contact or planar fit seal. When the limiting ball 15 is pressed against the end face of the connector 14 by the second return spring 18 and the abutment 16, since the ball diameter is larger than the hole diameter, the limiting ball 15 will not sink into the through hole, but will instead form a continuous annular contact line with the sharp edge of the periphery of the through hole through its spherical surface. This annular contact line generates high contact stress under the action of spring force, thereby achieving reliable blocking of the fluid channel. When the reverse fluid pressure exceeds the threshold, the limiting ball 15 is pushed open, the contact line separates, and the flow channel opens.

[0055] Compared to traditional surface contact seals involving spherical and conical surfaces or spherical and planar surfaces, annular line contact seals offer higher contact pressure, achieving better sealing performance under the same spring force and effectively preventing minor leaks at low pressures. The line contact structure significantly reduces frictional resistance between the limiting ball 15 and the connecting member 14, allowing for more sensitive and smooth movement of the limiting ball 15 during opening and resetting, avoiding response delays caused by sticking or jamming. If the ratio is below 1.2:1 (i.e., the ball diameter is relatively small), the limiting ball 15 is prone to sinking into the through-hole, leading to poor sealing or even jamming. If the ratio is above 1.5:1 (i.e., the ball diameter is too large), the contact line is too close to the top of the ball, resulting in a narrow sealing area that is prone to wear and failure, and also increases the required opening pressure. This design achieves a balance between sealing reliability, movement sensitivity, and manufacturing economy, while extending the service life of the limiting ball 15 and the connecting member 14.

[0056] In one implementation, the valve body is provided with external or internal threads at both ends for connection to external pipelines.

[0057] The valve body 11 has a hollow cylindrical structure with a through hole running through both sides along its axial direction. Both ends of the valve body 11 are provided with external or internal threads for detachable, sealed connections to external pipelines. Specifically, depending on actual installation requirements, the inlet and outlet ends of the valve body 11 can both be configured with external threads, or both with internal threads, or one end can be externally threaded and the other internally threaded. External threads facilitate mating with pipelines equipped with internally threaded fittings, while internal threads facilitate direct screwing to pipe fittings with external threads.

[0058] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A valve assembly comprising: include: Valve body, front return spring, front limit concave ring, connector, limit ball, abutment, rear limit concave ring and rear return spring; The valve body is hollow inside and has a through hole along the axial direction that passes through both sides. The front return spring is located inside the valve body, with one end abutting against the inner wall of the valve body through hole; The front limiting concave ring has an inward concave ring structure. The other end of the front return spring abuts against the inward concave side of the front limiting concave ring. A through-hole is provided at the bottom of the inward concave of the front limiting concave ring. Several front side through holes are provided on the side wall of the front limiting concave ring. The connector is fixedly installed on the side of the front limiting concave ring away from the valve body through hole. The connector has a central through hole in the middle that is connected to the front central through hole. The central through hole of the connector has several side through holes in the circumference of the connector. The side through holes of the connector are blocked by the front limiting concave ring. The limiting ball is located on the side of the connector away from the front limiting recess ring and blocks the central through hole of the connector; The abutment is recessed on the side facing the limiting ball to form a spherical limiting groove for limiting the limiting ball. The abutment abuts against the limiting ball through the spherical limiting groove, keeping the limiting ball in a state of blocking the central through hole of the connector. The abutment is provided with a central protrusion on the side away from the limiting ball. The central protrusion extends into the interior of the return spring. The abutment extends outward from the outer periphery of the side facing the limiting ball to form an annular abutment platform. The annular abutment platform abuts against one end of the return spring. The rear limiting concave ring has an inward concave ring structure. A through-hole is provided at the bottom of the concave rear limiting concave ring. The end of the rear return spring away from the abutment extends into the concave cavity of the rear limiting concave ring and is limited to prevent the rear limiting concave ring from coming out of the valve body through hole.

2. A valve assembly according to claim 1, characterized in that: The diameter of the spherical limiting groove opening is smaller than the diameter of the limiting ball, and the radius of the bottom of the spherical limiting groove matches the radius of the limiting ball.

3. A valve assembly according to claim 1, characterized in that: The valve body, front return spring, rear return spring, limit ball, and abutment are all coated with anti-corrosion coating or made of stainless steel.

4. A valve assembly according to claim 1, characterized in that: Several front side through holes are evenly distributed along the circumferential direction of the side wall of the front limiting concave ring, and the front side through holes are circular through holes or waist-shaped through holes.

5. A valve assembly according to claim 1, characterized in that: The outer peripheral wall of the rear limiting concave ring is provided with a wear-resistant coating, which is a polytetrafluoroethylene coating or a ceramic coating.

6. A valve assembly according to claim 1, characterized in that: The annular abutment platform has an annular positioning groove on the side facing the rear return spring, and the end of the rear return spring is embedded in the annular positioning groove; the end of the central protrusion has a chamfer or rounded corner.

7. A valve assembly according to claim 1, characterized in that: The inner depth of the front limiting concave ring is greater than the compression stroke of the front return spring, and the inner depth of the rear limiting concave ring is greater than the compression stroke of the rear return spring.

8. A valve assembly according to claim 1, characterized in that: The ratio of the diameter of the limiting ball to the diameter of the central through hole of the connector is 1.2:1 to 1.5:1, so that the limiting ball forms an annular line contact seal when blocking the central through hole of the connector.

9. A valve assembly according to claim 1, characterized in that: The valve body has external or internal threads at both ends for connection to external pipelines.

Images