Jamesbury™ Quadra-Powr™ spring diaphragm quarter turn actuators, QPX series

For use in both modulating control and on-off service

Jamesbury spring diaphragm QPX series quarter turn actuators are designed for use in both modulating control and on-off service. These actuators offer an exceptionally long cycle life and are well suited to operate almost any type of rotary valve. QPX actuator is designed for smooth and efficient quarter-turn valve operation and it provides safe and reliable operation even when minimal supply pressure is available.

Rugged and reliable

Smooth operation

Accurate positioning

Low maintenance


  • Rolling diaphragm for minimum friction
  • Low friction bearings – factory lubricated for lifetime
  • Field reversible for spring to open or close simply by flipping actuator over
  • Safety contained springs prevent hazards of inadvertent ejection during maintenance
  • Corrosion resistant – two layer epoxy and polyurethane paint with stainless steel fasteners
  • Adjustable stops for both open and closed positions
  • Wide input pressure range – up to 7 bar (100 psi)


Action: Single acting
Supply media: Air, water, mineral-based hydraulic fluid
Torque output: 15 to 796 Nm (11 to 587 lb-ft)
Operating pressure: 1.4 - 7 bar (20 - 100 psi)
Temperature range: -29 to +66 °C / -20 to 150 °F

Mechanical lock-out, 100% adjustable stop, tropicalization for wet and humid environments, fast operation and manual override