Festo HEL Series On/off Valve

The Festo HEL Series On/off Valve is designed to slowly pressurize and vent pneumatic systems, in conjunction with the HE and HEE on/off valves. They are available in three size variants - Mini, Midi, and Maxi - with varying pneumatic connection sizes. The valves feature a piston spool design and can be mounted in any orientation, suitable for use with compressed air or inert gases. The duration of the pressure build-up is set using a restrictor attached to the valve cap, allowing the outlet pressure to rise slowly. The main seat opens when the switch-through pressure is reached, at approximately 50% of the input pressure. This gradual pressure build-up helps drives move slowly and reliably into the initial position, avoiding sudden and erratic movements.