Because ball valves typically use rubber, nylon, and PTFE as seat sealing materials, their operating temperature is limited by the material of the seat sealing ring. The shut-off function of a ball valve is achieved by the metal ball pressing against the plastic seat under the influence of the medium (in floating ball valves). Under certain contact pressure, the seat sealing ring undergoes localized elastic-plastic deformation. This deformation compensates for the manufacturing precision and surface roughness of the ball, ensuring the sealing performance of the ball valve.
Furthermore, since the seat sealing ring of a ball valve is usually made of plastic, the fire resistance and fireproofing of the ball valve must be considered when selecting its structure and performance. This is especially important in the petroleum, chemical, and metallurgical industries, where ball valves are used in equipment and pipeline systems containing flammable and explosive media.
Ball valves are generally recommended for piping systems requiring two-position regulation, strict sealing, resistance to mud, wear, constriction, rapid opening and closing (1/4 turn), high-pressure shut-off (large pressure differential), low noise, cavitation and vaporization, minimal leakage to the atmosphere, low operating torque, and low fluid resistance.
Ball valves are also suitable for lightweight structures, low-pressure shut-off (small pressure differential), and corrosive media piping systems. They can also be used in cryogenic (deep cryogenic) equipment and piping systems. In oxygen piping systems in the metallurgical industry, ball valves that have undergone rigorous degreasing treatment are required. Full-bore welded ball valves are required when main pipelines in oil and gas pipelines need to be buried underground. For applications requiring regulating performance, ball valves with a special V-shaped opening structure should be selected. In petroleum, petrochemical, chemical, power, and urban construction industries, metal-to-metal sealed ball valves can be used in piping systems operating at temperatures above 200 degrees Celsius.
