Fisher 685 series piston actuators provide medium to high thrust output for a variety of medium to very large Fisher sliding-stem valves, including the easy-e™, HP, EH, FB, and 461 valves.The double-acting design of the actuator results in stiff, precise positioning. Spring-return constructions are also available and offer a fail open or closed mode of operation when paired with a valve.
FeaturesMaximum thrusts of up to 354 kN (79,000 lbf) can be produced, depending on construction.Depending on size, strokes of up to 610 mm (24 in) are available.The double-acting construction allows for stiff, precise positioning.A side-mounted handwheel is available for all sizes except the size 28, which uses a hydraulic hand pump for manual override control.Internal bias spring constructions are available for applications requiring a mechanical fail mode.Low friction piston seals and cylinder coatings reduce sliding friction and wear.
