FAILSAFE THERMAL BYPASS VALVE FOR COOLING SYSTEM

摘要

A thermal bypass valve for a heat exchanger circuit includes a valve housing forming a valve chamber including a bypass passage and ports for the flow of heat exchange fluid into and out of the valve chamber as well as a bypass port defined by a valve seat. Two axially aligned thermally sensitive actuators are mounted in the chamber, each with an actuator body and a movable piston extendible from one end of the body. One piston operably engages the actuatory body associated with the other piston. Each actuator body is normally movable in the chamber in response to extension of its piston. One actuator extends its piston at a higher temperature than the temperature required for the other actuator to extend its piston. A bypass valve member is mounted on one actuator and can be moved by either actuator from an open position to a closed position.