US 5,251,459 AGranted

Thermal expansion valve with internal by-pass and check valve

AssigneeEmerson Electric Co.

InventorsThomas Grass, Robert W. Haul

Life of this patent

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Abstract

A reversible flow thermal expansion valve for use in a heat system is disclosed wherein the thermal expansion valve includes a valve body having a flowpath therethrough with an inlet and outlet, an expansion port within the flowpath, and an expansion valve to open and close the expansion port. An internal by-pass flow path by-passes the expansion port for reverse flow through the expansion valve. A check valve in the by-pass flow path prevents refrigerant from by-passing the expansion port during regular, forward flow through the expansion valve. The check valve has a spring to bias the check valve normally closed, and a bypass port communicating between a check valve guide path chamber and a check valve outlet in order to relieve pressure in the guide path chamber and increase the flow rate through the check valve.

In a heat pump system comprising a compressor having an inlet and an outlet, a first heat exchanger to be located outdoor, a second heat exchanger to be located indoors, said indoor and outdoor heat exchangers being in communication with one another, a shiftable valve connected to the outlet and the inlet of the compressor and to the outdoor and indoor heat exchangers, said valve being selectively shiftable between a first position in which refrigerant is delivered from the outlet of the compressor to the outdoor heat exchanger such that the heat pump system is operated in a cooling mode and a second position in which refrigerant is delivered form the outlet of said compressor to said indoor heat exchanger such that said heat pump system is operated in a heating mode, and at least one thermostatic expansion valve between said indoor and said outdoor heat exchangers, said thermostatic expansion valve comprising a valve body including a flowpath therethrough having an inlet and an outlet, a thermal expansion port in said flowpath, movable valve means to selectively open and close said expansion port, wherein the improvement comprises:

an internal by-pass flow path within said valve body, said by-pass flowpath having a check valve therein, said check valve being in fluid communication with said valve body flowpath inlet and with said valve body flowpath outlet, said check valve comprising a check valve seat, a movable check valve ball separate from said expansion valve means, means for biasing said check valve toward its said closed position, and means for fully opening said check valve;
said check valve ball being movable in a guide path between a closed position in which said check valve member engages said check valve seat thereby to block the flow of refrigerant through said by-pass flow path from said inlet to said outlet, and an open position in which said check valve member is clear of said check valve seat thereby to permit flow of refrigerant from said outlet to said inlet through said by-pass flow path around said expansion port;
said means for fully opening said check valve including a pressure relief port in said guide path, said pressure relief means providing an escape for fluid contained in said guide path.

Facts

Application

07/861,318Filed 31 Mar 1992 · continuation in part

Priority

28 May 1991

Granted

12 Oct 1993

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

F25B 13/00
Compression machines, plants or systems, with reversible cycle
F25B 41/325
Expansion valves: having two or more valve members
F25B 41/335
With the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant: via diaphragms
F25B 41/38
Expansion means; Dispositions thereof: specially adapted for reversible cycles, e.g. bidirectional expansion restrictors

Abstract

Claims10