Manual Gear Operator
Designs vary, but most include a self-locking, declutchable worm gear which is designed to provide a secure engagement keeping the valve firmly in position. Declutchable manual gear overrides are usually designed to be “sandwiched” between a pneumatic actuator and quarter-turn valve, allowing the operator to manually operate a pneumatic actuator in case of emergency power or air loss.
Construction normally protects the gears in a completely enclosed, weatherproof and permanently lubricated enclosure. The operation is done via some type of hand wheel. A wide variety of torque outputs are available.
When selecting a declutchable manual gear override consideration must be given to valve torque requirements, weight, size, mounting, operating environment, and criticality of application. An experienced valve application engineer should be consulted prior to selection.