Since the ball valve usually uses rubber, nylon and polytetrafluoroethylene as the seat sealing ring material, its use temperature is limited by the seat sealing ring material. The cut-off function of the ball valve is achieved by pressing the metal ball against the plastic seat under the action of the medium (floating ball valve). Under the action of certain contact pressure, the seat sealing ring has elastic-plastic deformation in some areas. This deformation can compensate the manufacturing accuracy and surface roughness of the ball, and ensure the sealing performance of the ball valve.
the fire resistance and fire resistance of the ball valve
In addition, since the seat sealing ring of the ball valve is usually made of plastic, when selecting the structure and performance of the ball valve, the fire resistance and fire resistance of the ball valve must be considered, especially in the petroleum, chemical, metallurgical and other sectors, in the flammable and explosive media Ball valves are used in the equipment and pipe system, and more attention should be paid to fire resistance and fire prevention.
Generally, in two-position adjustment, strict sealing performance, mud, abrasion, necking channel, rapid opening and closing action (1/4 turn opening and closing), high pressure cut-off (large pressure difference), low noise, cavitation and vaporization, In piping systems with a small amount of leakage to the atmosphere, small operating torque and small fluid resistance, ball valves are recommended.
Ball valves are also suitable for piping systems with light structure, low pressure cut-off (small pressure difference), and corrosive media.
Ball valves can also be used in low temperature (cryogenic) devices and pipeline systems.
In the oxygen pipeline system of the metallurgical industry, ball valves that have undergone strict degreasing treatment are required.
When the main line in the oil pipeline and gas pipeline needs to be buried underground, full-diameter welded ball valves are required.
When the adjustment performance is required, a ball valve with a special structure with a V-shaped opening should be selected.
In petroleum, petrochemical, chemical, electric power, and urban construction, metal-to-metal sealed ball valves can be used for pipeline systems with operating temperatures above 200°C.
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