Rostra Precision Controls, Inc.

David Piscitelli

Kevin W Lamb

Kenneth Lionello

Kenneth Lionello Iii

Edward A Voytek

An improved heat exchanger, and flow control valve assembly associated with a heat exchanger, of the type wherein the temperature responsive flow control valve is integrated with the heat exchanger the valve assembly is well suited for mounting at the discharge port of the heat exchanger, without relying on rigid interaction with the inside wall of the discharge header or the tube ends in the discharge header. In this manner, the same basic valve assembly can be utilized in a variety of heat exchanger headers, merely by adapting the connection between the end of the valve assembly closest to the discharge port, and the housing or related structure of the heat exchanger at the discharge port. To the extent a relatively standard size valve assembly is to be used with heat exchangers having discharge conduits of different cross sectional area or shape, a baffle member can be placed around the valve assembly before insertion into the header.

Thermally actuated valve assembly

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.

Self-contained thermal actuator

A specially profiled wax retaining cup and piston guide are crimped together to compress a peripheral portion of a diaphragm wax seal to the extent of extruding the diaphragm material to form both an axial seal and at least one radial seal. The compressed, extruded diaphragm seal provides a wax containment seal capable of withstanding high wax pressures that generate high actuation forces. A wax filled thermal actuator reliably produces an actuating force F sufficient to lift a load in a range of 2500 to 6000 times the mass of the actuator. Performance of the thermal actuator may also be expressed in terms of the internal pressures generated and delivered to the bottom of the actuator piston. The pressure applied to the bottom of the actuator piston in the inventive actuator is in the range of approximately 1700 to 8800 psi (124 to 620 kg/cm).

Thermal actuator

A thermal flow control valve uses a cylindrical valve sleeve in a stepped bore to regulate fluid flow between an inlet and an outlet. A wax filled actuator is coupled to the valve sleeve to move the sleeve from an open position in which radial flow openings in the sleeve communicate with a larger diameter portion of the stepped bore to a closed position in which the radial flow openings are closed by a sleeve chamber closely surrounding the sleeve. A flow-through end cap closes one end of the stepped bore and provides an axially aligned fixed stop for the actuator piston. Two-way, three-way and mixing embodiments of the valve are disclosed.

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Wallingford, CT, United States of America

David Piscitelli