Biffi Alga Algas AlgasQA Double acting and spring return pneumatic quarter convert actuators for on-off and modulating control of valves in heavy duty services. Readily available for output torques to 750,000 Nm. The Viking Pneumatic Actuator is really a spring loaded to open, rolling diaphragm, piston operated valve. It's used https://donovanabwpi.thezenweb.com/A-Review-Of-pneumatic-actuator-48558156