Adjustable hard seal fixed ball valve

Abstract

The application discloses an adjustable hard sealing fixed ball valve, which comprises a middle body, left and right bodies connected to the two sides of the middle body respectively, a ball body arranged in a valve cavity, a valve rod for driving the ball body to rotate, a fixed plate and a valve seat assembly, wherein the valve seat assembly comprises a valve seat body, a wedge-shaped block and two C-shaped rings, and the wedge-shaped block is arranged between the two C-shaped rings. The valve seat adopts double C-shaped ring ring sealing, the wedge-shaped block is additionally arranged in the middle, pressure can push the C-shaped ring to the large end of the wedge-shaped block, so that a more compact seal is formed, and after the seal is loosened under high temperature and high pressure, the C-shaped ring and the wedge-shaped block can effectively compensate the deformation.

Description

Technical Field

[0001] This utility model relates to an adjustable hard-seal fixed ball valve, belonging to the field of ball valves. Background Technology

[0002] With the continuous increase in medium pressure and temperature in industrial pipeline systems, the sealing reliability and opening / closing stability of valves under complex conditions such as high temperature, high pressure, corrosiveness, or the presence of solid particles have gradually become key indicators. As an important type of shut-off valve, the sealing compensation capability of the fixed ball valve, the machining accuracy of the valve body and fixed plate, the ball positioning accuracy, and the pressure relief method of the valve cavity directly affect the valve's sealing life, torque, and the smoothness of the opening and closing process. Under harsh operating conditions, any minute dimensional error or fit deviation in the valve structure can be magnified exponentially into wear on the sealing surface, increased torque, and even valve leakage.

[0003] However, several key deficiencies still exist in existing fixed ball valve structures. Traditional valve seats rely on fixed spring preload to form a seal, which cannot effectively compensate for changes in size and deformation caused by high temperature and pressure. The fixed plate and the middle body are usually machined and assembled separately, and the unavoidable errors between the shaft hole and the end face reduce the positioning accuracy of the ball, resulting in excessive torque and unstable sealing performance. The valve cavity pressure relief structure relies on the area difference between the valve seat piston and the sealing surface, and its pressure relief pressure and sealing specific pressure are mutually restrictive, making it difficult to achieve both accurate pressure relief and reliable sealing. At the same time, the valve seat preload in traditional structures cannot be adjusted according to actual working conditions, making it difficult to achieve both low torque and good sealing. Therefore, it is urgent to improve the existing technology to solve the core problems such as insufficient sealing compensation under high temperature and pressure, positioning deviation caused by large machining errors, uncontrollable pressure relief, and inability to adjust the preload. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide an adjustable hard-seal fixed ball valve.

[0005] An adjustable hard-seal fixed ball valve includes a middle body, a left body and a right body respectively connected to both sides of the middle body, a ball disposed in the valve cavity, a valve stem for driving the ball to rotate, a fixing plate, and a valve seat assembly. The valve seat assembly includes a valve seat body, a wedge block, and two C-rings, with the wedge block disposed between the two C-rings.

[0006] Furthermore, the small end of the wedge block faces the direction of the medium flow channel, and the large end of the wedge block faces the direction of the valve cavity; a gasket is provided at the bottom of the two C-rings, and a first spring is provided on the side of the gasket away from the C-ring. The first spring abuts against the valve seat body and is used to provide an initial preload force to the C-rings and wedge blocks, pushing the C-rings and wedge blocks to form a tight fit with the valve seat body.

[0007] Furthermore, the valve seat body is provided with a push groove, and the large end of the wedge block is fitted into the push groove.

[0008] Furthermore, the valve seat assembly is mounted on the fixed plate, and a pre-tightening adjustment mechanism is provided between the valve seat assembly and the fixed plate; the pre-tightening adjustment mechanism includes an adjusting screw and a second spring, and the adjusting screw passes through the fixed plate and is connected to the valve seat body.

[0009] Furthermore, the second spring is sleeved on the adjusting screw and located between the fixing plate and the valve seat body. The adjusting screw is used to adjust the compression of the second spring, thereby adjusting the preload of the valve seat assembly.

[0010] Furthermore, the middle body and the fixed plate are engaged with each other by axially extending wedge-shaped teeth, and the fixed plate is fixed to the middle body by fasteners and positioning pins that are inclined perpendicular to the valve medium channel axis.

[0011] Furthermore, the middle body is provided with inner wedge-shaped teeth, and the fixing plate is provided with outer wedge-shaped teeth that match the shape of the inner wedge-shaped teeth. The inner wedge-shaped teeth and the outer wedge-shaped teeth are in an interference fit or transition fit in the axial direction.

[0012] Furthermore, the fastener is an obliquely arranged fastening screw, and the fixing plate and the middle body are provided with screw holes and pin holes with the axis inclined to the valve diameter direction. The screw holes are used to install fastening screws, and the pin holes are used to install positioning pins.

[0013] Furthermore, the fixing plate is provided with a fixing shaft hole, and the middle body is provided with a middle body shaft hole corresponding to the fixing shaft hole. The fixing shaft hole and the middle body shaft hole are coaxial holes that are machined in one go after the fixing plate is installed in the middle body.

[0014] Furthermore, the two end faces of the fixing plate are symmetrical planes machined with the fixing shaft hole as the reference.

[0015] The beneficial effects of this utility model are as follows: 1. The valve seat adopts a double C-ring seal with an added wedge block in the middle. The pressure will push the C-ring towards the large end of the wedge block to form a tighter seal. After the seal loosens under high temperature and high pressure, the C-ring and wedge block can effectively compensate for the deformation.

[0016] 2. The fixed plate and the middle body are machined simultaneously. Before machining the shaft holes and end faces, the middle body and the support plate are machined with intermeshing wedge-shaped teeth. Then, the middle body and the left and right bodies are positioned by pins and fastening screws. Then, the upper and lower shaft holes are machined. This can eliminate the assembly and machining errors between the middle body and the fixed plate, thereby improving the sealing performance, reducing the valve torque, and increasing the valve life.

[0017] 3. Positioning of the fixed plate and the middle body: Since the fixed plate and the middle body are fixed before processing, there are no assembly and processing errors between the fixed plate and the middle body. This ensures the positional accuracy of the ball after installation, which can improve sealing performance, reduce valve torque, and increase valve life.

[0018] 4. Pressure relief in the middle cavity is achieved by pushing the seal, which satisfies both the appropriate sealing pressure ratio and allows for pressure relief at a lower pressure.

[0019] 5. The valve seat preload adopts an adjustable structure. The spring compression can be adjusted by rotating the adjusting screw, and the spring preload can be adjusted according to the actual sealing conditions and sealing environment. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of this utility model.

[0021] Figure 1 This is a schematic diagram of the main structure of this utility model; Figure 2 This is a side view of the present invention; Figure 3 for Figure 1 Enlarged detail view of point A in the middle; In the diagram, 1. Middle body; 11. Inner wedge tooth; 12. Middle body shaft hole; 2. Left body; 3. Right body; 4. Ball; 5. Valve stem; 6. Fixing plate; 61. Outer wedge tooth; 62. Fixing shaft hole; 63. Screw hole; 64. Pin hole; 7. Valve seat assembly; 71. Valve seat body; 711. Push groove; 72. Wedge block; 73. C-ring; 74. Washer; 75. First spring; 8. Adjusting screw; 9. Second spring; 10. Fastening screw; 11. Locating pin. Detailed Implementation

[0022] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0023] It should be noted that all uses of "first" and "second" in the embodiments of this utility model are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of this utility model. Subsequent embodiments will not explain this in detail.

[0024] The directional and positional terms used in this utility model, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for the purpose of explaining and understanding this utility model, and not for limiting the scope of protection of this utility model.

[0025] like Figure 1-3 The illustration shows an embodiment of an adjustable hard-seal fixed ball valve according to this utility model. It includes a central body 1, a left body 2 and a right body 3 connected to both sides of the central body 1, a ball 4 disposed within the valve cavity, a valve stem 5 for rotating the ball 4, a fixing plate 6, and a valve seat assembly 7. The valve seat assembly 7 includes a valve seat body 71, a wedge block 72, and two C-rings 73, with the wedge block 72 disposed between the two C-rings 73.

[0026] The small end of the wedge block 72 faces the direction of the medium flow channel, and the large end of the wedge block 72 faces the direction of the valve cavity; the bottom of the two C-rings 73 is provided with a gasket 74, and a first spring 75 is provided on the side of the gasket 74 away from the C-rings 73. The first spring 75 abuts against the valve seat body 71 and is used to provide an initial preload to the C-rings 73 and the wedge block 72, pushing the C-rings 73 and the wedge block 72 towards the valve seat body 71 to form a tight fit with it.

[0027] The first spring can be multiple sets of cylindrical helical springs or disc springs distributed circumferentially. These springs provide preload, bringing the C-ring, wedge, and valve seat into contact to form an initial seal. As the pressure increases, the medium pushes the C-ring towards the larger end of the wedge, creating a tighter seal. When the valve seat deforms under high temperature and pressure, the C-ring moves synchronously with the deformation, filling the gaps and forming a stable seal. When the pressure in the middle cavity is too high and pressure relief is needed, the medium pushes the C-ring towards the smaller end of the wedge, reducing the sealing force and allowing for pressure relief in the middle cavity.

[0028] The release of pressure in the valve cavity is generally achieved by the medium in the cavity pushing the valve seat. During the process of the valve seat being pushed open by the medium, the valve seat sealing surface and the ball will separate. At this time, impurities in the medium will enter the middle of the sealing surface, and the sealing surface will be scratched during the opening and closing process. Moreover, the release pressure is directly related to the size of the sealing surface and the outer diameter of the piston. When the size of the sealing surface is close to the outer diameter of the piston, the release pressure will be very small, but the sealing specific pressure will also be very small, making it difficult for the valve to seal. When the size of the sealing surface and the outer diameter of the piston are significantly different, the sealing specific pressure will be relatively high, and the sealing performance will be better, but the release pressure will be very large, making it difficult for the valve to release pressure. Therefore, traditional structures cannot achieve a structure with both a high sealing specific pressure and a low release pressure. However, the valve seat release of this utility model is achieved by the medium pushing the C-ring and wedge block, which can precisely adjust the release pressure and arbitrarily adjust the valve seat sealing specific pressure.

[0029] The reason why fixed ball valves are more prone to leakage at higher temperatures and pressures is that the valve seat is easily deformed under high temperature and pressure. However, the valve seat seal of this invention will have a greater sealing force under high temperature and pressure due to the wedge block principle, under the deformation caused by temperature and the push of pressure. Therefore, the seal will be more stable as the pressure and temperature increase.

[0030] In some embodiments, the valve seat body 71 is provided with a push groove 711, and the large end of the wedge block 72 is fitted into the push groove 711. The push groove 711 ensures that the wedge block 72 always moves along the axial direction of the valve or a predetermined trajectory, thus guaranteeing a uniform distribution of sealing force.

[0031] Optionally, in some embodiments, the valve seat assembly 7 is mounted on the fixed plate 6, and a preload adjustment mechanism is provided between the valve seat assembly 7 and the fixed plate 6; the preload adjustment mechanism includes an adjusting screw 8 and a second spring 9, the adjusting screw 8 passing through the fixed plate 6 and connected to the valve seat body 71. Further, the second spring 9 is sleeved on the adjusting screw 8 and located between the fixed plate 6 and the valve seat body 71, the adjusting screw 8 being used to adjust the compression of the second spring 9, thereby adjusting the preload of the valve seat assembly 7.

[0032] When the adjusting screw 8 is tightened clockwise, it pulls the valve seat body 71 closer to the fixed plate 6, thereby compressing the second spring 9. By controlling the screw-in depth, technicians can precisely set the initial thrust of the valve seat on the ball. For gaseous media, a higher initial sealing pressure is required, so the compression can be increased; for liquid media such as water or lubricating oil, the compression can be appropriately reduced to decrease the operating torque. This structure avoids the drawback of traditional valves that require disassembly and spring replacement to adjust the preload. Under good sealing conditions, the preload can be reduced to decrease torque and reduce wear between sealing surfaces. Under harsh and severe sealing conditions, the preload can be increased to ensure a tight seal.

[0033] Optionally, in some embodiments, the middle body 1 and the fixing plate 6 are engaged with each other by axially extending wedge-shaped teeth, and the fixing plate 6 is fixed to the middle body 1 by fasteners and positioning pins 11 that are inclined perpendicular to the axis of the valve medium passage. Further, the middle body 1 is provided with inner wedge-shaped teeth 11, and the fixing plate 6 is provided with outer wedge-shaped teeth 61 that match the shape of the inner wedge-shaped teeth 11. The inner wedge-shaped teeth 11 and the outer wedge-shaped teeth 61 are interference fit or transition fit in the axial direction.

[0034] The fixed plate and the middle body are engaged by wedge-shaped teeth. At this time, the fixed plate can only move in the axial direction. Then, screw holes and pin holes are machined obliquely in the direction perpendicular to the inner cavity of the valve. The fixed plate is firmly fixed to the middle body by fastening screws and positioning pins. At this time, the fixed plate is completely fixed to the middle body and cannot be moved at all.

[0035] Compared to traditional planar bonding, the wedge-shaped tooth structure can withstand greater alternating loads, making it particularly suitable for applications involving frequent switching or severe fluid pulsation. While this structure is complex to manufacture, high-precision tooth shaping or broaching processes ensure the meshing accuracy of the teeth, thereby guaranteeing the stability of the fixed plate 6 as the foundation for the sphere's support.

[0036] In some embodiments, the fastener is an obliquely arranged fastening screw 10. The fixing plate 6 and the middle body 1 are provided with screw holes 63 and pin holes 64 whose axes are inclined to the valve diameter direction. The screw holes 63 are used to install the fastening screw 10, and the pin holes 64 are used to install the positioning pin 11.

[0037] Optionally, in some embodiments, the fixing plate 6 is provided with a fixing shaft hole 62, and the middle body 1 is provided with a middle body shaft hole 12 corresponding to the fixing shaft hole 62. The fixing shaft hole 62 and the middle body shaft hole 12 are coaxial holes that are machined in one go after the fixing plate 6 is installed in the middle body 1. Further, the two end faces of the fixing plate 6 are symmetrical planes machined with the fixing shaft hole 62 as the reference.

[0038] The lower shaft hole of the middle body 1 and the shaft hole 62 of the supporting ball on the fixed plate 6 are bored on the same machine tool and in the same clamping after the fixed plate 6 has been firmly installed on the middle body 1. This process eliminates cumulative errors, allowing the coaxiality of all shaft holes to be controlled within an extremely small tolerance range. Using this high-precision shaft hole connection as a reference, the two end faces of the fixed plate 6 are then precision machined to ensure the perpendicularity of the end face to the axis and the parallelism between the two end faces. This extreme geometric precision ensures that the ball 4 is always at the theoretical center during rotation, and will not generate additional squeezing force on the valve seat due to eccentricity, thereby significantly reducing the opening and closing torque of the valve, enabling easy operation even on large-diameter, high-pressure valves, while also ensuring uniform sealing.

[0039] Typically, the body and positioning plates are machined separately. Machining errors are unavoidable during the processing of the shaft holes in both positioning plates and the body. This error is often the cause of valve leakage, high torque, and rapid wear. Using a method of first positioning and fixing the parts before machining can avoid these errors. Furthermore, machining the two parts together after fixing them allows for simultaneous processing of three parts in the same operation, reducing machining steps and increasing efficiency.

[0040] In summary, the working principle of the embodiments of this application is as follows: During valve assembly, the fixing plate 6 engages with the middle body 1 via wedge teeth 61 / 11 and is fully locked in place by oblique fastening screws 10 and locating pins 11. Subsequently, the entire assembly is precision machined to ensure extremely high coaxiality. The valve seat assembly 7 is mounted on the fixing plate 6 via adjusting screws 8, and the initial preload is set by adjusting the compression of the second spring 9.

[0041] When the valve is in operation, the first spring 75 pushes the gasket 74, causing the C-ring 73 to come into close contact with the wedge block 72, forming an initial seal. When the medium enters the flow channel, the pressure pushes the C-ring 73 towards the larger end of the wedge block 72, and the C-ring 73 expands radially, more tightly filling the micro-gap between the ball and the valve seat. The greater the pressure, the more reliable the seal.

[0042] When high-temperature operating conditions cause component deformation, the C-ring 73 moves and deforms accordingly to maintain a dynamic seal.

[0043] When the pressure in the cavity rises abnormally and pressure needs to be released, the reverse pressure pushes the C-ring 73 toward the small end of the wedge block 72, reducing the contact pressure and allowing the fluid to be discharged through the gap, thus achieving automatic safety protection.

[0044] Throughout the process, the high-precision structure ensures low-torque operation, the adjustable mechanism ensures adaptability to different media, and the unique sealing structure solves the leakage problem of hard-seal valves under harsh operating conditions.

[0045] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

[0046] Although the present invention has been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the specific embodiments disclosed. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. An adjustable hard-seal fixed ball valve, characterized in that: The valve includes a central body, a left body and a right body connected to both sides of the central body, a ball disposed in the valve cavity, a valve stem for driving the ball to rotate, a fixing plate, and a valve seat assembly. The valve seat assembly includes a valve seat body, a wedge block, and two C-rings, with the wedge block disposed between the two C-rings.

2. The adjustable hard-seal fixed ball valve as described in claim 1, characterized in that: The small end of the wedge block faces the direction of the medium flow channel, and the large end of the wedge block faces the direction of the valve cavity; the bottom of the two C-rings is provided with a gasket, and the side of the gasket away from the C-ring is provided with a first spring. The first spring abuts against the valve seat body and is used to provide an initial preload force to the C-rings and wedge blocks, pushing the C-rings and wedge blocks to form a tight fit with the valve seat body.

3. The adjustable hard-seal fixed ball valve as described in claim 2, characterized in that: The valve seat body is provided with a push groove, and the large end of the wedge block is fitted into the push groove.

4. The adjustable hard-seal fixed ball valve as described in claim 1, characterized in that: The valve seat assembly is mounted on the fixed plate, and a pre-tightening adjustment mechanism is provided between the valve seat assembly and the fixed plate; the pre-tightening adjustment mechanism includes an adjusting screw and a second spring, and the adjusting screw passes through the fixed plate and is connected to the valve seat body.

5. The adjustable hard-seal fixed ball valve as described in claim 4, characterized in that: The second spring is sleeved on the adjusting screw and located between the fixed plate and the valve seat body. The adjusting screw is used to adjust the compression of the second spring, thereby adjusting the preload of the valve seat assembly.

6. The adjustable hard-seal fixed ball valve as described in claim 1, characterized in that: The middle body and the fixed plate are engaged with each other by axially extending wedge-shaped teeth. The fixed plate is fixed to the middle body by fasteners and positioning pins that are inclined perpendicular to the axis of the valve medium channel.

7. The adjustable hard-seal fixed ball valve as described in claim 6, characterized in that: The middle body is provided with inner wedge-shaped teeth, and the fixing plate is provided with outer wedge-shaped teeth that match the shape of the inner wedge-shaped teeth. The inner wedge-shaped teeth and the outer wedge-shaped teeth are in an interference fit or transition fit in the axial direction.

8. The adjustable hard-seal fixed ball valve as described in claim 6, characterized in that: The fastener is an obliquely arranged fastening screw. The fixing plate and the middle body are provided with screw holes and pin holes whose axes are inclined to the valve diameter direction. The screw holes are used to install fastening screws, and the pin holes are used to install positioning pins.

9. The adjustable hard-seal fixed ball valve as described in claim 1, characterized in that: The fixing plate is provided with a fixing shaft hole, and the middle body is provided with a middle body shaft hole corresponding to the fixing shaft hole. The fixing shaft hole and the middle body shaft hole are coaxial holes that are machined in one go after the fixing plate is installed in the middle body.

10. The adjustable hard-seal fixed ball valve as described in claim 9, characterized in that: The two end faces of the fixing plate are symmetrical planes machined with the fixing shaft hole as the reference.

Images