Fluid metering valve

摘要

A fluid metering valve includes a gear rack which is slidable on a valve stem in which a spring counteracts the force of an actuator to maintain a constant load on the gear mechanism to prevent backlash. Corresponding stop mechanisms between the gear and the shaft of a rotary actuator come into engagement with each other near a fully closed position of the fluid metering valve for zero calibration purposes upon power loss to the actuator. A single valve member and a single actuator of the fluid metering valve provides for both a shut-off function and a metering function.