Pneumatic Diaphragm Actuators The simple design of our pneumatic diaphragm actuators with a robust power diaphragm makes them universal in application and also ensures hysteresis-free control across the entire actuating range. These pneumatic valve actuators can be opened or closed using spring force or control air – an option that can be switched at any time. The integrated adjusting spring ensures that the pneumatic control actuator always assumes a defined limit position. This is accomplished with very short actuating times meaning that alongside their control tasks, ARCA diaphragm actuators also play a key role in safeguarding the plant. The pneumatic diaphragm actuators can also be configured for manual emergency intervention if requested.