FAIL-SAFE ACTUATOR FOR ROTARY VALVES

摘要

An actuator for a rotary valve includes a fail-safe mechanism for automatically opening or closing the valve upon the occurrence of a predetermined condition. The actuator also includes a mechanism for permitting the manual operation of the valve from the open to closed position, and vice versa, and to a continuum of positions between the open and closed positions even when the fail-safe mechanism is activated. A biased clutch activates the fail-safe mechanism and also couples a worm-gear drive for effecting the manual operation of the valve.