Abstract: A by-pass valve fitting assembly in which the valve element is retained in a cage having a front end support rigidly trapped between a cylindrical body and an inlet fitting, with the other end cantilevered in a flow cavity of the body, such that the biasing spring is seated in the cantilevered support to urge the valve element through the front support against a sealing face on the inlet fitting.

Abstract: A self-contained thermal actuator positions the piston return member inside the actuator cup. The inventive configuration eliminates the guide and diaphragm seal that closed the open end of the wax filled cup in the typical thermal actuator configuration. The piston and an O-ring seal seated in an annular recess defined by the piston contain the thermally responsive wax. A return member within the cup and engaged between axially spaced, radially overlapping shoulders on the cup and piston biases the piston toward its pre-actuation position. The return member may be a spring or an elastomeric O-ring that also seals the thermal actuator against intrusion of contaminants from the use environment. The piston is closely received in the cup for guided axial reciprocation therein.