High-temperature ball valve sealing structure and characteristics

High-temperature ball valve sealing structure and characteristics

High-Temperature Ball Valve Sealing Structure

1. High-temperature ball valves feature low fluid resistance, convenient operation, rapid opening and closing, and good and reliable sealing. They are widely used in petrochemical, long-distance pipeline, and urban heating industries.

2. High-temperature ball valve seats are made of polytetrafluoroethylene (PTFE) (or filled with PTFE), known as soft-seal ball valves, with an operating temperature not exceeding 200°C.

3. Valves with metal seats are called hard-seal ball valves or high-temperature ball valves, with an operating temperature of 350°C or higher. To meet the demands of high-temperature operating conditions, domestic and international ball valve manufacturers have optimized the sealing structure of high-temperature ball valves to significantly reduce the opening and closing torque, significantly extend their service life, and significantly improve their performance. It has been improved.

Sealing Characteristics of High-Temperature Ball Valves

1. The sealing characteristics of high-temperature ball valves primarily utilize metal seals. High-temperature ball valves are suitable for a wide temperature range. The coefficients of thermal expansion of various metals do not differ significantly. As long as the correct selection is made, they are essentially consistent. Adjustment for temperature difference deformation is possible.

2. The disadvantages of high-temperature ball valve seals are the hardness of the material and the high specific pressure required for the seal. Due to the high specific pressure of the seal, even with pre-tightening, the valve seat and ball will experience severe wear. Furthermore, the high coefficient of friction of the metal sealing surface increases the opening and closing torque of the ball valve. Therefore, most high-temperature ball valves use resilient seals with reliable performance, strong elastic compensation, and a wide applicable temperature range, making them suitable for both floating and stationary ball valves.

3. Due to the effects of pre-tightening and hydraulic pressure, the valve seat and ball are compressed, and the sealing surface of the valve seat deforms and seals. The sealing effect depends on the valve seat’s ability to effectively compensate for the roundness and micro-uniformity of the ball under fluid pressure and pre-tightening.