Since pneumatic three-way ball valves usually use rubber, nylon and polytetrafluoroethylene as the seat sealing ring material, its operating temperature is limited by the seat sealing ring material. The cut-off function of the ball valve is accomplished by pressing the metal ball against each other between the plastic valve seats under the action of the medium (floating ball valve). Under the action of appropriate contact pressure, the valve seat sealing ring deforms elastically and plastically in some areas. This deformation can compensate the manufacturing accuracy and surface roughness of the ball to maintain the sealing performance of the ball valve.
In addition, since the valve seat sealing ring of pneumatic three-way ball valve is usually made of plastic, when selecting the structure and performance of the ball valve, it is necessary to consider the fire resistance and fire resistance of the ball valve. For example, in the petroleum, chemical, metallurgical and other sectors, the Ball valves are used in equipment and piping systems for explosive media, and more attention should be paid to fire resistance and fire prevention.
Generally, in two-position adjustment, strict sealing performance, mud, wear, necking channel, fast opening and closing action (1/4 turn opening and closing), high pressure cut-off (large pressure difference), low noise, cavitation and vaporization, It is recommended to use a ball valve in a piping system with a small amount of leakage to the atmosphere, small operating torque and small fluid resistance.
Features
(1) The fluid resistance is small, and its resistance coefficient is equal to that of a pipe section of the same length.
(2) Simple structure, small size and light weight.
(3) Good sealing performance. At present, most of the sealing surface materials of ball valves are made of plastics, which have good sealing performance, and they are also commonly used in vacuum systems.
(4) Convenient operation, fast opening and closing, and only rotate 90° from fully open to fully closed, which is convenient for remote control.
(5) Convenient maintenance, simple structure of the ball valve, and generally movable sealing rings, making it easier to disassemble and replace.
(6) When fully open or fully closed, the sealing surface of the ball and the valve seat is isolated from the medium. When the medium passes, it will not cause erosion of the sealing surface of the pneumatic three-way ball valve
(7) The scope of application is wide, the diameter is from a few millimeters to a few meters, and it can be applied from high vacuum to high pressure.
Pneumatic three-way ball valve applicable occasions:
Pneumatic three-way ball valve is also suitable for light structure, low pressure cut-off (small pressure difference), corrosive medium piping system. 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 lines in the oil and gas pipelines need to be buried underground, full-diameter welded ball valves are required. When adjusting performance is required, a ball valve with a V-shaped opening structure 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 degrees. Pneumatic three-way ball valves are mainly used in chemicals, petroleum, textiles, electricity, and food. , Refrigeration, aviation, aerospace, papermaking and other industrial fields.
