In ball valves, the disc spring assembly plays a critical role by providing continuous preload force to the sealing packing and preventing leakage. Disc springs are known for their narrow bearing surface, high precision, excellent elasticity, and corrosion resistance. These characteristics allow them to maintain optimal performance even in high-temperature, high-pressure, and complex media environments.
Ball valves operate with a spherical closure element that has a round passage, and the valve is opened or closed by rotating the ball 90 degrees around the valve stem axis. Ball valves are not only structurally simple and offer good sealing performance, but they are also compact, lightweight, and require minimal material usage. Their small installation size, low operating torque, and ease of quick operation make them ideal for various applications.
Role of Disc Springs in Ball Valves
The disc spring assembly inside the ball valve serves to provide sustained preload force to the sealing packing, preventing leakage. The advantages of disc springs in this application include:
Narrow Lever Arm: Their narrow bearing surface allows for precise force application.
High Elasticity: Disc springs can maintain their flexibility even under extreme conditions.
Corrosion Resistance: High-quality materials, such as stainless steel, are often used to ensure long-lasting performance.
High Performance in Harsh Conditions: They remain effective even in high temperatures, high pressures, and complex media environments.
Due to the limited installation space, the outer-to-inner diameter ratio (D/d) of disc springs used in ball valves is typically between 1.4 and 1.8. For very small diameter ratios (D/d < 1.8), stainless steel is commonly used to manufacture the springs, ensuring both durability and performance.
Key Functions of Disc Springs in Ball Valves
Disc springs are crucial in ensuring the sealing performance of ball valves. The proper selection of disc spring design and mechanical properties directly impacts the valve's sealing effect. An improper design, such as insufficient preload force or excessive sealing pressure, can cause damage to the sealing surface (e.g., scratches) or result in leakage failure.
To design the appropriate disc spring for a ball valve, the minimum required preload pressure must be calculated based on the spring’s force, the dimensions of the ball, valve body, and seat. This is often done by selecting an initial disc spring size, calculating the force it can provide according to the national standard GB/T 1972-2005, Appendix C, and refining the design through finite element analysis (FEA). After multiple adjustments and optimization, the ideal spring design is achieved.
Once the design is finalized and the product is manufactured, it undergoes strict force verification. If no visible leakage occurs after the disc spring is installed in the ball valve, it indicates that the spring's preload force meets the required specifications.
Additional Benefits of Disc Springs
In addition to providing preload force, disc springs in ball valves also act as elastic supports. They can serve as buffers to absorb vibrations and shocks. During media flow, the elasticity of the disc spring ensures that the valve operates more smoothly and predictably, enhancing the safety and stability of the ball valve.
The selection of suitable materials and sizes for disc springs in ball valve design and manufacturing can greatly improve the valve's performance and longevity. Properly designed disc springs ensure a more efficient and reliable pipeline control solution across various industries.
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Raleigh Spring Technology Co., Ltd.
