Control valves with pneumatic drive are used when regulation requires a fail-safe mode (spring to close / spring to open – in case of irregularities, the valve automatically closes / opens). Pneumatic valves are usually accompanied by a positioner (for regulation) or a solenoid valve for on/off functions. When defining a control valve with pneumatic drive, it is necessary to specify:

• The type of function it performs (on/off or regulation)
• The type of pneumatic drive (double-acting or single-acting/spring-return)
• Whether there are conditions for supplying the pneumatic drive with compressed air
• The number of springs