What is difference between a pneumatic on-off valve and a pneumatic control valve

The pneumatic ball valve consists of a pneumatic actuator and a ball valve. It is a valve driven by compressed air and is usually used in applications requiring automatic control. Pneumatic ball valves are available in two different control modes: switch type and regulation type to meet different needs of customers. What is the difference between the pneumatic on-off valve and the pneumatic control valve?

First, the optional accessories are different: the pneumatic switch valve can be equipped with solenoid valve, limit switch, filter pressure reducing valve, etc.; the pneumatic control valve must be equipped with a positioner to realize the adjustment function, in addition to the positioner can also be equipped with a solenoid valve, Limit switch and filter pressure reducing valve.

Second, the use of different functions: Pneumatic switch valve is mainly for the opening and closing of the pipeline medium and emergency cut off. Pneumatic control valve is used together with the positioner. It can control the operation by inputting 4~20mADC signal and 0.4~0.7MPa air source to realize the adjustment of pressure, flow, temperature and liquid level.

Third, other differences: Pneumatic switch valves have no special requirements for flow characteristics other than open and closed. Pneumatic control valves have higher requirements for circulation characteristics from open to closed; pneumatic switch valves have higher requirements for switching speed than adjustment. Valves, pneumatic regulating valves have higher requirements for opening stability between opening and closing than switching valves; the distinction between pneumatic regulating valves and pneumatic switching valves is due to the different use cases, the different emphasis on the indicators, and There are big differences in the structure of the valve body and the drive mechanism.