Abstract: The research background of high-pressure and large-diameter plug valves is introduced. The valve is analyzed from the equal deformation design of the valve body sealing surface, equal width of sealing surfaces of valve bodies and plugs, low torque of valves, lasting balance of sealing and anti-deformation. The matters needing attention in the design and manufacturing process of high-pressure and large-diameter pressure-balanced plug valves are obtained.
High-pressure and large-diameter pressure-balanced plug valves are essential components in various industries, including oil and gas, chemical, and power generation. These valves are designed to handle high-pressure fluids while maintaining a tight seal to prevent leakage. One of the key features of these valves is their large diameter, which allows for the smooth flow of fluids through the pipeline. This is especially important in applications where a high volume of fluid needs to be transported efficiently. The larger diameter also reduces pressure drop across the valve, minimizing energy loss. Another crucial aspect of these valves is their pressure-balanced design. This means that the forces acting on the plug are balanced, allowing for easy operation even under high-pressure conditions. The pressure-balanced design also ensures that there is minimal friction between the plug and seat, reducing wear and tear on the valve components. Furthermore, these valves are equipped with advanced sealing mechanisms to ensure a tight seal even at high pressures. This prevents any leakage that could lead to environmental hazards or loss of valuable resources. With their advanced sealing mechanisms, these valves provide a reliable solution for maintaining system integrity and preventing leakage.
1. Overview
In 2012, in order to ensure the supply of natural gas energy and revitalize China's equipment manufacturing industry, the government proposed key equipment for oil and gas pipelines being made in China, and the valve project being made in China began to be officially implemented. The pressure-balanced plug valve project is included. After the successful advancement of this project, the domestic production of pressure-balanced plug valves with a diameter of being less than and equal to 16 inches and a pressure of Class 900 has been achieved. Plug valves beyond this range still rely on imports. due to the untimely supply of such imported plug valves due to COVID-19, project construction has been seriously affected. Taking into account the high price, long manufacturing cycle and many uncertain factors of such imported products, the 2020 National Oil and Gas Pipeline Group Corporation Construction Project Management Branch has proposed requirements for large-diameter pressure-balanced plug valves being made in China, involving valve specifications of 24 inches and Class 900 or CL600. In the process, certain experiences have accumulated in the design and manufacturing process of large-diameter plug valves.
High-pressure and large-diameter pressure-balanced plug valves are essential components in various industries, including oil and gas, chemical, and power generation. These valves are designed to handle high-pressure fluids while maintaining a tight seal to prevent leakage. One of the key features of these valves is their large diameter, which allows for the smooth flow of fluids through the pipeline. This is especially important in applications where a high volume of fluid needs to be transported efficiently. The larger diameter also reduces pressure drop across the valve, minimizing energy loss. Another crucial aspect of these valves is their pressure-balanced design. This means that the forces acting on the plug are balanced, allowing for easy operation even under high-pressure conditions. The pressure-balanced design also ensures that there is minimal friction between the plug and seat, reducing wear and tear on the valve components. Furthermore, these valves are equipped with advanced sealing mechanisms to ensure a tight seal even at high pressures. This prevents any leakage that could lead to environmental hazards or loss of valuable resources. With their advanced sealing mechanisms, these valves provide a reliable solution for maintaining system integrity and preventing leakage.
1. Overview
In 2012, in order to ensure the supply of natural gas energy and revitalize China's equipment manufacturing industry, the government proposed key equipment for oil and gas pipelines being made in China, and the valve project being made in China began to be officially implemented. The pressure-balanced plug valve project is included. After the successful advancement of this project, the domestic production of pressure-balanced plug valves with a diameter of being less than and equal to 16 inches and a pressure of Class 900 has been achieved. Plug valves beyond this range still rely on imports. due to the untimely supply of such imported plug valves due to COVID-19, project construction has been seriously affected. Taking into account the high price, long manufacturing cycle and many uncertain factors of such imported products, the 2020 National Oil and Gas Pipeline Group Corporation Construction Project Management Branch has proposed requirements for large-diameter pressure-balanced plug valves being made in China, involving valve specifications of 24 inches and Class 900 or CL600. In the process, certain experiences have accumulated in the design and manufacturing process of large-diameter plug valves.
2. Equal deformation of sealing surfaces of valve bodies
One key aspect to consider when designing plug valve bodies is equal deformation across their sealing surfaces. This refers to maintaining uniform stress distribution during operation, which ultimately leads to improved sealing performance and extended valve lifespan. Equal deformation can be achieved through careful material selection and design considerations. Firstly, using materials with high strength and good elasticity properties is essential to withstand the forces exerted on the sealing surfaces. Additionally, incorporating features such as reinforcement ribs or gussets can help distribute stress evenly. Furthermore, proper machining techniques are vital in achieving equal deformation. Precise tolerances must be maintained during manufacturing to ensure that all sealing surfaces have consistent dimensions. This prevents uneven stress concentration and potential leakage points.
The key point in the design of the valve body structure of high-pressure and large-diameter pressure-balanced plug valves is to ensure equal deformation at the matching sealing surfaces of the valve body and the plug. The structural length and flange standard are selected according to user requirements. Design flow channel and middle cavity structure of the valve body according to requirements for the flow or flow area, and then select the valve body’s wall thickness to design the valve body shape. The inner cavity design is reviewed and verified using flow field analysis software to try to avoid sudden changes in the flow field and reduce the impact of flow rate changes on the inner wall. The design ideas for large and small diameters are the same. If the high-pressure large-diameter valve body is designed with the same wall thickness as the small-diameter valve body, the sealing surface between the valve body and the plug will have an abnormal structure, poor rigidity, and uneven deformation, which is detrimental to valve sealing. Therefore, when designing the shape of high-pressure and large-diameter valves, a detailed design should be carried out to strengthen partial areas to ensure that the deformation of the above-mentioned sealing surfaces is as consistent as possible and the valve’s sealing effect is balanced at any position. The valve body’s sealing part is shown in Figure 1.
Figure 1 The sealing part of the valve body
The key point in the design of the valve body structure of high-pressure and large-diameter pressure-balanced plug valves is to ensure equal deformation at the matching sealing surfaces of the valve body and the plug. The structural length and flange standard are selected according to user requirements. Design flow channel and middle cavity structure of the valve body according to requirements for the flow or flow area, and then select the valve body’s wall thickness to design the valve body shape. The inner cavity design is reviewed and verified using flow field analysis software to try to avoid sudden changes in the flow field and reduce the impact of flow rate changes on the inner wall. The design ideas for large and small diameters are the same. If the high-pressure large-diameter valve body is designed with the same wall thickness as the small-diameter valve body, the sealing surface between the valve body and the plug will have an abnormal structure, poor rigidity, and uneven deformation, which is detrimental to valve sealing. Therefore, when designing the shape of high-pressure and large-diameter valves, a detailed design should be carried out to strengthen partial areas to ensure that the deformation of the above-mentioned sealing surfaces is as consistent as possible and the valve’s sealing effect is balanced at any position. The valve body’s sealing part is shown in Figure 1.
Figure 1 The sealing part of the valve body
Next: High-pressure and Large-diameter Pressure-balanced Plug Valves (Part Two)
Previous: An Overview of Valve Seats, Valve Discs and Valve Cores
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