Pneumatic Actuators

Pneumatic actuators convert compressed air energy into valve motion — linear thrust for globe, gate, and control valves, or rotary torque for ball, butterfly, and plug valves. The actuator type matches the valve motion type: linear actuators push valve stems up and down, rotary actuators turn valve shafts 90°. FLOWKS manufactures five pneumatic actuator configurations spanning both motion types and three force-generation mechanisms. Diaphragm pneumatic actuators produce linear thrust through a flexible diaphragm that deflects under air pressure — low supply pressure (40-80 psi), large diaphragm area compensates for the lower pressure, spring-return fail-safe, and the standard actuator for process control valves where low hysteresis and precise stem positioning matter. Diaphragm pneumatic actuators with handwheel add a declutchable manual override for plant startup and air-supply-outage operation — same actuator performance, plus handwheel positioning when air isn't available. Scotch yoke pneumatic actuators produce variable rotary torque through a piston-driven yoke mechanism — torque peaks at the initial breakout position to unseat quarter-turn valves, and the geometry delivers higher torque at large valve sizes (8"-48" butterfly, 8"-24" ball) where rack-and-pinion actuators can't generate enough force. Linear stroke cylinders use a piston-in-cylinder design for linear thrust — higher supply pressure (up to 150 psi), longer stroke capability (up to 12"), more compact than diaphragm actuators at equivalent thrust, specified for gate valves with long stem travel and tight-installation spaces. AT series cylinders are rack-and-pinion rotary actuators in extruded aluminum bodies — constant torque across 90° stroke, NAMUR accessory mounting, compact and lightweight for small-to-medium quarter-turn valve automation up to 12" butterfly and 8" ball sizes.

FLOWKS pneumatic actuators automate valve operation across both linear-stroke and quarter-turn valve types. Diaphragm pneumatic actuators deliver linear thrust for globe, gate, and control valves — low supply pressure, spring-return fail-safe, low hysteresis for precise modulating control, thrust range 100-10,000 lbf. Diaphragm pneumatic actuators with handwheel add declutchable manual override for startup commissioning and air-supply-outage operation — same actuator plus manual positioning capability when compressed air is unavailable. Scotch yoke pneumatic actuators produce variable rotary torque for large quarter-turn valves — torque peaks at initial breakout for reliable ball and butterfly valve unseating, output range 500-100,000 Nm across model sizes, spring-return or double-acting. Linear stroke cylinders provide piston-driven linear thrust for long-stroke gate and globe valves — higher supply pressure up to 150 psi, stroke range 1"-12", compact installation where diaphragm actuator size doesn't fit. AT series cylinders are rack-and-pinion quarter-turn actuators in extruded aluminum — constant torque output, NAMUR solenoid and accessory mounting, compact lightweight design for automated ball and butterfly valves up to moderate sizes, torque range 10-5,000 Nm.