Stop valve and preparation method thereof

Abstract

The invention discloses a stop valve and a preparation method thereof. The stop valve comprises an execution mechanism; a valve body; the support is used for connecting the valve body and an executing mechanism; the valve seat is arranged in the valve body; the valve element can move longitudinally to seal the valve seat or be separated from the valve seat; the valve cover is arranged in the valve body and is positioned above the valve seat; the valve rod penetrates through the valve cover and is in transmission connection with the executing mechanism; and the actuating mechanism drives the valve rod to move longitudinally. And the manufacturing precision of the stop valve is greatly improved by defining strict parameter standards such as dimensional precision and surface roughness of each component.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, and in particular to a cut-off valve and a preparation method thereof. Background Art

[0002] A shut-off valve is a high-performance product with fast action and tight shutoff. Used in conjunction with high-power solenoid valves, pressure reducing valves, and other accessories, it can automatically and quickly discharge, urgently shut off, or redirect fluids in automated system pipelines, achieving automatic control of process parameters such as pressure, flow, temperature, and liquid level. It is particularly suitable for high-temperature and high-pressure applications requiring reliability and high shutoff performance. Existing shut-off valves have low manufacturing precision, making them susceptible to leakage and failure risks due to manufacturing errors. Based on this, a shut-off valve and its manufacturing method have been designed. Summary of the Invention

[0003] In order to overcome at least one of the above-mentioned drawbacks of the prior art, the present invention provides a shut-off valve and a method for manufacturing the same. By specifying strict dimensional accuracy, surface roughness and other parameter standards for each component, the manufacturing accuracy of the shut-off valve is greatly improved.

[0004] The technical solution adopted by the present invention to solve the problem is:

[0005] A shut-off valve comprises: an actuator; a valve body; a bracket, the bracket being used to connect the valve body and the actuator; a valve seat, the valve seat being arranged in the valve body; a valve core, the valve core being able to move longitudinally to seal the valve seat or detach from the valve seat; a valve cover, the valve cover being arranged in the valve body and located above the valve seat; and a valve stem, the valve stem passing through the valve cover and being transmission-connected to the actuator, so as to drive the valve stem to move longitudinally through the actuator.

[0006] By adopting the above solution, the valve core can move longitudinally to seal or disengage from the valve seat. This design can quickly and effectively cut off or circulate the fluid, meet the basic functional requirements of the shut-off valve for fast action and strict shut-off, and ensure the control accuracy of the fluid in the automation system conveying pipeline.

[0007] Furthermore, filler is filled between the valve cover and the valve stem to achieve a sealed connection between the valve cover and the valve stem.

[0008] By adopting the above solution, filler is filled between the valve cover and the valve stem, thereby achieving a sealed connection between the valve cover and the valve stem, effectively preventing fluid from leaking from the gap between the valve cover and the valve stem, improving the sealing reliability of the shut-off valve, reducing the risk of leakage, and ensuring the normal operation of the system; good sealing can reduce the corrosion and wear of the fluid on components such as the valve stem and valve cover, thereby extending the overall service life of the shut-off valve and reducing maintenance costs.

[0009] Furthermore, a medium inlet and a medium outlet are respectively provided on both sides of the valve body, and the medium inlet and the medium outlet are in an S-shaped structure.

[0010] By adopting the above solution, the medium inlet and medium outlet on both sides of the valve body are in an S-shaped structure. This design can optimize the flow path of the fluid in the valve body, reduce the resistance to fluid flow, reduce pressure loss, and improve fluid transportation efficiency; the S-shaped structure can buffer the impact force when the fluid enters and flows out, reduce the impact and vibration on the valve body and related components, which is beneficial to improving the stability and reliability of the shut-off valve and reducing the risk of failure caused by vibration.

[0011] Furthermore, the valve body and the valve cover are made of chromium-molybdenum alloy steel, the valve seat is made of tungsten-cobalt hard alloy, the valve core and the valve cover are made of stainless steel, the filler is made of polytetrafluoroethylene, and the bracket is made of carbon steel.

[0012] By adopting this approach, different components are made of different materials, fully considering the operating conditions and performance requirements of each component in the shut-off valve. For example, the valve body and bonnet are made of chromium-molybdenum alloy steel, which has excellent strength and high-temperature resistance, suitable for high-temperature and high-pressure applications. The valve seat is made of tungsten-cobalt cemented carbide, which is hard and wear-resistant, ensuring the seal between the valve seat and the valve core and its service life. The valve core and bonnet are made of stainless steel for corrosion resistance. The packing is made of polytetrafluoroethylene, which has excellent sealing and chemical stability. The bracket is made of carbon steel, which meets the strength requirements while being relatively low-cost. This material selection approach fully utilizes the advantages of each material to improve the overall performance of the shut-off valve.

[0013] Furthermore, the actuator is a pneumatic actuator, an electric actuator or a hydraulic actuator.

[0014] By adopting the above solution, the actuator is a pneumatic actuator, an electric actuator or a hydraulic actuator, which provides users with a variety of options. Users can flexibly select the appropriate actuator type according to different automation systems, working environments and usage requirements, thereby improving the versatility and applicability of the shut-off valve.

[0015] A method for preparing a shut-off valve, comprising the above-mentioned shut-off valve, is as follows:

[0016] S1, valve body processing;

[0017] S11. The forging ratio is controlled between 3-5 to ensure the metal structure is dense. After forging, ultrasonic flaw detection is carried out with a flaw detection sensitivity of not less than level II to ensure that there are no cracks and inclusions inside the valve body;

[0018] S12. The inner diameter of the valve body is controlled at H7 level, with a surface roughness of Ra ≤ 1.6 μm. The valve body is turned on a CNC lathe and the rough turning-semi-finishing turning-finishing turning process is used to gradually achieve the required accuracy.

[0019] S13. The quenching temperature of the valve body is controlled at 850-880℃, and the tempering temperature is 600-650℃. After heat treatment, the hardness test is carried out and the hardness value must reach HB220-260;

[0020] S2, valve seat processing;

[0021] S21. Use isostatic pressing to prepare the valve seat blank. The molding pressure is controlled at 150-200 MPa to ensure uniform material density. The sintering temperature is set at 1400-1450℃ and the sintering time is 2-3 hours. After sintering, the density is tested and it must reach more than 98% of the theoretical density.

[0022] S22, the outer diameter of the valve seat is controlled at R7 level, and the interference with the inner hole of the valve body is controlled at 0.03-0.05mm. It is ground by internal and external cylindrical grinders to ensure the matching accuracy;

[0023] S3, valve core processing;

[0024] S31, using precision casting technology, the valve core shell baking temperature is controlled at 1000-1050℃, and the pouring temperature is 1550-1600℃;

[0025] S32, the dimensional accuracy of the valve core shape is controlled within ±0.03mm, and it is processed using CNC lathes and CNC milling machines;

[0026] S4, valve stem processing;

[0027] S41, the outer diameter of the valve stem is controlled at h6 level, with surface roughness Ra≤0.8μm, and is turned using a high-precision CNC lathe;

[0028] S42, valve stem quenching temperature is 1020-1050℃, tempering temperature is 550-600℃, and the surface hardness after heat treatment reaches HRC40-45;

[0029] S43. Perform external cylindrical grinding on the valve stem to further improve dimensional accuracy and surface quality. The dimensional accuracy is controlled at h5 level and the surface roughness Ra ≤ 0.4 μm.

[0030] S5, valve cover processing;

[0031] S51. The inner diameter dimensional accuracy of the stuffing box on the valve cover is controlled at H7 level, with a surface roughness of Ra ≤ 1.6μm. It is processed using a CNC boring machine and measured with an inner diameter micrometer after processing to ensure dimensional accuracy;

[0032] S52, the bonnet quenching temperature is controlled at 850-880℃, the tempering temperature is 600-650℃, and the hardness test is carried out after heat treatment. The hardness value must reach HB220-260.

[0033] By adopting the above solution, the valve body performance is improved, the valve seat quality is guaranteed, the valve core is accurately processed, the valve stem performance is improved, and the valve cover processing is optimized.

[0034] Furthermore, when the polytetrafluoroethylene fibers are woven, the weaving density is controlled at 8-10 stitches / cm, which is precisely controlled by the parameters of the weaving machine. The woven filler rope is subjected to a tensile strength test, and the tensile strength is not less than 15 MPa.

[0035] By adopting the above solution, when weaving the polytetrafluoroethylene fiber, the weaving density is controlled at 8-10 stitches / cm, which is precisely controlled by the parameter settings of the weaving machine. This appropriate weaving density can ensure the density and elasticity of the packing, thereby ensuring that the packing can form a good seal between the valve cover and the valve stem to prevent fluid leakage; the braided packing rope is required to undergo a tensile strength test, and the tensile strength is not less than 15MPa, which ensures that the packing has sufficient strength during use, can withstand the friction and pressure during the movement of the valve stem, is not easy to break or damage, extends the service life of the packing, and improves the sealing reliability and stability of the shut-off valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the cross-sectional structure of an embodiment of the present invention;

[0037] The meanings of the accompanying figures are as follows: 1. Actuator; 2. Valve body; 3. Bracket; 4. Valve seat; 5. Valve core; 6. Valve cover; 7. Valve stem; 8. Packing; 9. Medium inlet; 10. Medium outlet. DETAILED DESCRIPTION

[0038] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described and discussed below in conjunction with the drawings of the present invention. Obviously, what is described here is only a part of the examples of the present invention, not all the examples. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] To facilitate understanding of the embodiments of the present invention, the following will be further explained with reference to specific embodiments as examples in conjunction with the accompanying drawings, and each embodiment does not constitute a limitation on the embodiments of the present invention.

[0040] In the description of the present invention, it should be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0042] See Figure 1 The present invention discloses a shut-off valve, comprising an actuator 1, a valve body 2, a bracket 3, a valve seat 4, a valve core 5, a valve cover 6, and a valve stem 7. The bracket 3 is used to connect the valve body 2 and the actuator 1; the valve seat 4 is arranged in the valve body 2; the valve core 5 can move longitudinally to seal the valve seat 4 or detach from the valve seat 4; the valve cover 6 is arranged in the valve body 2 and is located above the valve seat 4; the valve stem 7 passes through the valve cover 6 and is transmission-connected to the actuator 1, so as to drive the valve stem 7 to move longitudinally through the actuator 1. The valve core 5 can move longitudinally to seal or detach from the valve seat 4. This design can quickly and effectively realize the shut-off or circulation of the fluid, meet the basic functional requirements of the shut-off valve for fast action and tight shut-off, and ensure the control accuracy of the fluid in the conveying pipeline of the automation system.

[0043] The valve body 2 is provided with a medium inlet 9 and a medium outlet 10 on either side, each of which forms an S-shaped structure. This S-shaped structure optimizes the fluid flow path within the valve body 2, reduces resistance to fluid flow, lowers pressure loss, and improves fluid delivery efficiency. The S-shaped structure cushions the impact of fluid entering and exiting the valve body, reducing impact and vibration on the valve body 2 and related components, thereby improving the stability and reliability of the valve and reducing the risk of failure due to vibration.

[0044] The valve body 2 and valve cover 6 are made of chromium-molybdenum alloy steel, the valve seat 4 is made of tungsten-cobalt carbide, the valve core 5 and valve cover 6 are made of stainless steel, the packing 8 is made of polytetrafluoroethylene, and the bracket 3 is made of carbon steel. Different components are made of different materials, fully considering the working conditions and performance requirements of each component in the shut-off valve. For example, the valve body 2 and valve cover 6 are made of chromium-molybdenum alloy steel, which has excellent strength and high-temperature resistance, and can adapt to high-temperature and high-pressure environments; the valve seat 4 is made of tungsten-cobalt carbide, which has high hardness and good wear resistance, ensuring the sealing performance and service life between the valve seat 4 and valve core 5; the valve core 5 and valve cover 6 are made of stainless steel, which is corrosion-resistant; the packing 8 is made of polytetrafluoroethylene, which has excellent sealing and chemical stability; and the bracket 3 is made of carbon steel, which meets the strength requirements while being relatively low in cost. This material selection scheme fully utilizes the advantages of each material to improve the overall performance of the shut-off valve. The actuator 1 is a pneumatic actuator 1, an electric actuator 1 or a hydraulic actuator 1. The actuator 1 is a pneumatic actuator 1, an electric actuator 1 or a hydraulic actuator 1, which provides users with a variety of options. Users can flexibly select the appropriate type of actuator 1 according to different automation systems, working environments and usage requirements, thereby improving the versatility and applicability of the shut-off valve.

[0045] The present invention also discloses a method for manufacturing a shut-off valve, comprising the aforementioned shut-off valve, as follows: S1. Processing the valve body 2; S11. Controlling the forging ratio between 3 and 5 to ensure a dense metal structure. After forging, ultrasonic flaw detection is performed with a sensitivity of no less than Class II to ensure that the valve body 2 is free of cracks and inclusions; S12. The valve body 2 is turned on a CNC lathe, using a roughing-semi-finishing-finishing process to gradually achieve the required accuracy; S13. Controlling the quenching temperature of the valve body 2 between 850 and 880°C and the tempering temperature between 600 and 650°C. After heat treatment, a hardness test is performed, with the hardness value reaching HB220-260; S2. Processing the valve seat 4; S21. Using an isostatic pressing process to prepare the valve seat 4 blank, with a molding pressure controlled between 150 and 200 MPa to ensure uniform material density. The sintering temperature is set at 1400-1450℃, the sintering time is 2-3 hours, and the density is tested after sintering. The density must reach more than 98% of the theoretical density; S22. The outer diameter size accuracy of the valve seat 4 is controlled at r7 level, and the interference with the inner hole of the valve body 2 is controlled at 0.03-0.05mm. It is ground by internal and external cylindrical grinders to ensure the matching accuracy; S3. Valve core 5 processing; S31. Using precision casting technology, the baking temperature of the valve core 5 shell is controlled at 1000-1050℃, and the pouring temperature is 1550-1600℃; S32. The dimensional accuracy of the valve core 5 shape is controlled at ±0.03mm, and it is processed by CNC lathe and CNC milling machine; S4. Valve stem 7 processing; S41. The outer diameter size accuracy of the valve stem 7 is controlled at h6 level, the surface roughness Ra≤0.8μm, and it is turned by high-precision CNC lathe; S42. Valve stem 7 quenching The quenching temperature is 1020-1050℃, the tempering temperature is 550-600℃, and the surface hardness reaches HRC40-45 after heat treatment; S43, the valve stem 7 is subjected to external cylindrical grinding to further improve the dimensional accuracy and surface quality. The dimensional accuracy is controlled at h5 level, and the surface roughness is Ra≤0.4μm; S5, the valve cover 6 is processed; S51, the inner diameter dimensional accuracy of the stuffing box 8 on the valve cover 6 is controlled at H7 level, and the surface roughness is Ra≤1.6μm. It is processed by CNC boring machine and measured with internal micrometer after processing to ensure dimensional accuracy; S52, the quenching temperature of the valve cover 6 is controlled at 850-880℃, and the tempering temperature is 600-650℃. The hardness is tested after heat treatment, and the hardness value needs to reach HB220-260, improve the performance of the valve body 2, ensure the quality of the valve seat 4, accurately process the valve core 5, enhance the performance of the valve stem 7, and optimize the processing of the valve cover 6. When the polytetrafluoroethylene fibers are woven, the weaving density is controlled at 8-10 stitches / cm and is precisely controlled by setting parameters of the weaving machine.The braided packing rope 8 needs to be tested for tensile strength, and the tensile strength is not less than 15MPa. When weaving polytetrafluoroethylene fibers, the weaving density is controlled at 8-10 stitches / cm, which is precisely controlled by the parameter settings of the braiding machine. This appropriate weaving density can ensure the density and elasticity of the packing 8, thereby ensuring that the packing 8 can form a good seal between the valve cover 6 and the valve stem 7 to prevent fluid leakage; the braided packing rope 8 needs to be tested for tensile strength, and the tensile strength is not less than 15MPa, which ensures that the packing 8 has sufficient strength during use, can withstand the friction and pressure during the movement of the valve stem 7, is not easy to break or damage, extends the service life of the packing 8, and improves the sealing reliability and stability of the shut-off valve.

[0046] By defining strict standards for dimensional accuracy, surface roughness, and other parameters for each component, the manufacturing precision of the shut-off valve has been significantly improved. Strict control of various process parameters during the manufacturing process, coupled with a comprehensive testing process, ensures the consistent quality of each component. Whether it's the heat treatment hardness of the valve body 2 or the performance testing of the actuator 1, the overall quality of the shut-off valve is more stable and reliable, reducing product rejection rates and improving the company's production efficiency and economic benefits. Precise manufacturing standards and strict process control enable this shut-off valve to meet the high-precision and high-reliability requirements of high-end industries such as petrochemicals, energy, and electricity.

[0047] The technical means disclosed in the solutions of the present invention are not limited to those disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above-mentioned technical features. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A shut-off valve, characterized in that: include: executive body; Valve body; a bracket, the bracket being used to connect the valve body and the actuator; a valve seat, the valve seat being arranged in the valve body; a valve core capable of longitudinally moving to seal against the valve seat or to separate from the valve seat; a valve cover, the valve cover being disposed in the valve body and located above the valve seat; The valve stem passes through the valve cover and is in transmission connection with the actuator so as to drive the valve stem to move longitudinally through the actuator.

2. A shut-off valve according to claim 1, characterized in that: Filling is filled between the valve cover and the valve stem to achieve a sealed connection between the valve cover and the valve stem.

3. A shut-off valve according to claim 2, characterized in that: A medium inlet and a medium outlet are respectively provided on both sides of the valve body, and the medium inlet and the medium outlet are in an S-shaped structure.

4. A shut-off valve according to claim 3, characterized in that: The valve body and the valve cover are made of chromium-molybdenum alloy steel, the valve seat is made of tungsten-cobalt hard alloy, the valve core and the valve cover are made of stainless steel, the filler is made of polytetrafluoroethylene, and the bracket is made of carbon steel.

5. A shut-off valve according to claim 4, characterized in that: The actuator is a pneumatic actuator, an electric actuator or a hydraulic actuator.

6. A method for preparing a cut-off valve, characterized in that: The cut-off valve according to any one of claims 1 to 5 is prepared as follows: S1, valve body processing; S11. The forging ratio is controlled between 3-5 to ensure the metal structure is dense. After forging, ultrasonic flaw detection is carried out with a flaw detection sensitivity of not less than level II to ensure that there are no cracks and inclusions inside the valve body; S12. The inner diameter of the valve body is controlled at H7 level, with a surface roughness of Ra ≤ 1.6 μm. The valve body is turned on a CNC lathe and the rough turning-semi-finishing turning-finishing turning process is used to gradually achieve the required accuracy. S13. The quenching temperature of the valve body is controlled at 850-880℃, and the tempering temperature is 600-650℃. After heat treatment, the hardness test is carried out and the hardness value must reach HB220-260; S2, valve seat processing; S21. Use isostatic pressing to prepare the valve seat blank. The molding pressure is controlled at 150-200 MPa to ensure uniform material density. The sintering temperature is set at 1400-1450℃ and the sintering time is 2-3 hours. After sintering, the density is tested and it must reach more than 98% of the theoretical density. S22, the outer diameter of the valve seat is controlled at R7 level, and the interference with the inner hole of the valve body is controlled at 0.03-0.05mm. It is ground by internal and external cylindrical grinders to ensure the matching accuracy; S3, valve core processing; S31, using precision casting technology, the valve core shell baking temperature is controlled at 1000-1050℃, and the pouring temperature is 1550-1600℃; S32, the dimensional accuracy of the valve core shape is controlled within ±0.03mm, and it is processed using CNC lathes and CNC milling machines; S4, valve stem processing; S41, the outer diameter of the valve stem is controlled at h6 level, with surface roughness Ra≤0.8μm, and is turned using a high-precision CNC lathe; S42, valve stem quenching temperature is 1020-1050℃, tempering temperature is 550-600℃, and the surface hardness after heat treatment reaches HRC40-45; S43. Perform external cylindrical grinding on the valve stem to further improve dimensional accuracy and surface quality. The dimensional accuracy is controlled at h5 level and the surface roughness Ra ≤ 0.4 μm. S5, valve cover processing; S51. The inner diameter dimensional accuracy of the stuffing box on the valve cover is controlled at H7 level, with a surface roughness of Ra ≤ 1.6μm. It is processed using a CNC boring machine and measured with an inner diameter micrometer after processing to ensure dimensional accuracy; S52, the bonnet quenching temperature is controlled at 850-880℃, the tempering temperature is 600-650℃, and the hardness test is carried out after heat treatment. The hardness value must reach HB220-260.

7. A method for preparing a cut-off valve according to claim 6, characterized in that: When the polytetrafluoroethylene fibers are woven, the weaving density is controlled at 8-10 stitches / cm, which is precisely controlled by the parameters of the weaving machine. The woven filler rope is tested for tensile strength, and the tensile strength is not less than 15 MPa.

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