Flow regulating valve apparatus for air conditioning systems

Abstract

A flow regulating valve for air conditioning systems is shown in which a body member (26, 26a-26e) is provided with a passageway (28, 28a-28f) which results in regulating flow of refrigerant into the evaporator of the air conditioning system under normal conditions. Under severe operating conditions, e.g., high ambient temperature and low or idle speeds, the system refrigerant pressure rises. This increases pressure in the evaporator and an increase in the saturation temperature of refrigerant in the evaporator. This increase in temperature is sensed by a thermostatic metal element (44, 80, 88) of the regulating valve which moves to increase restriction to the flow of the refrigerant fluid through the valve thereby decreasing pressure of the refrigerant entering the evaporator. In several embodiments the thermostatic metal element is in the form of a helix (44) with one end fixed to the body member and the opposite end attached to a sleeve (38, 38d) in certain embodiments and an end cap (54, 60, 68) in other embodiments to rotate the sleeve or end cap to restrict fluid flow in an auxiliary passage. In other embodiments the thermostatic metal element is a relatively straight strip (80, 88) having one end fixed to the body member and its opposite end, in one embodiment, movable toward and away from an auxiliary inlet port (34) and in another embodiment the opposite end is attached to a block (94) having a relatively smaller effective passage (29e) movable into and out of alignment with a larger passage (31e) to change the effective level of flow restriction.