A pneumatic actuator provides high stem force output for demanding service conditions. These actuators are usually air operated but some can be self operated by the process fluid.
Fisher spring and diaphragm pneumatic actuators can be ''direct-acting'', meaning that air to the diaphragm casing pushes the actuator stem downward.
Fisher linear piston actuators are powerful, double-acting actuators that provide accurate throttling or on-off operation for sliding-stem control valves.
Fisher rack-and-pinion rotary actuators are available in both double-acting and spring-return configurations.
Fisher self-operated actuators provide control for a wide variety of pressure regulation applications.