Since ball valves are usually made of rubber, nylon and PTFE as seat seal material, the temperature of the valve is limited by the material of the seat ring. The cut-off effect of the ball valve depends on the metal sphere under the action of the medium, the plastic valve seat between the pressure to complete each other (floating ball valve). The valve seat sealing ring under the action of certain contact pressure, the elastic-plastic deformation occurs in the local area.
This deformation compensates for the manufacturing accuracy and surface roughness of the sphere, ensuring the sealing performance of the ball valve.
Because the ball valve seat sealing ring is usually made of plastic, so in the choice of ball valve structure and performance, to consider the ball valve fire and fire, especially in the oil, chemical, metallurgy and other departments, in flammable, explosive medium equipment and piping system using ball valve, more attention should be paid to fire and fire.
Usually, in the double-position adjustment, tight sealing performance, mud, wear, necking channel, rapid opening and closing action (1/4), high-voltage cutoff (pressure differential), low noise, cavitation and gasification phenomenon, small leakage to the atmosphere, small operating torque, small fluid resistance piping system, the recommended use of ball valve. Ball valves are also suitable for use in piping systems with light construction, low pressure cutoff (low dropout voltage) and corrosive media. Ball valves are also available in cryogenic (deep cooling) and piping systems. In the metallurgical industry oxygen piping System, the use of a strict degreasing ball valve. Full bore welded ball valves are required for the main line in the pipeline and gas pipeline to be buried in the ground. A ball valve with a special structure with a V-shaped opening is required when regulating performance is required.
In the petroleum, petrochemical, chemical, electric power, urban construction, the operating temperature of more than 200 degrees in the pipeline system can choose metal-to-metal sealed ball valve.