• Hytork Controls Inc

Air Fail Safe Actuator

Air Fail Safe Actuator is used for torque requirement valves up to 28500 inch.lbs (3220 Nm.) The AFS (Air Fail Safe) actuator is designed to provide a high fail stroke torque in a double rack and pinion actuator that cannot be achieved using springs. All the safety and performance features of double rack and pinion actuators are maintained as is the Hytork "XL" reliability. Using the time proven air accumulator system, and modern design techniques, Hytork produces air chamber modules with all the pneumatic circuitry Safety protected within. The HYTORK AFS maintains the highest seen air supply pressure within the chamber modules, to be released upon control demand. This design also prevents closure "creeping" when air supply pressures drop, which occurs with all spring return designs. Torque output is constant in the powered stroke with only a small drop off on the fail stoke. The AFS operates as a double acting actuator in both directions until there is a loss of supply pressure. When this loss occurs, the compressed air stored in the chambers powers the actuator to close the valve. This makes the AFS Series suitable for use in ON/OFF and MODULATING CONTROL situations while still providing the fail-safe requirement. The AFS is supplied already furnished with an installed, direct mount solenoid valve. The coil type is selected to suit your site requirements. This saves on site piping and ensures the assembly has been fully tested.

High Performance In The Fail And Powered Strokes
Constant torque output during normal operation
A very low torque drop off on the fail stroke provides higher usable torque than spring designs

High Reliability
All components are located and protected inside the air chamber modules
A proven, successful track record

Compact Heavy Duty Design
Similar in size to spring return designs yet three times the power output
Central mounting over the valve prevents pipe twisting
Balanced design eliminates the need for support brackets
No side loads to wear the valve stem packing
Lower actuator cost