Patent ID: 7980482

Claim:
A thermostatic expansion valve for an air conditioning system, the valve comprising: a valve body having an evaporator inlet port and an evaporator outlet port, the valve body further including a suction line port and a liquid line port; a sensor chamber formed within the valve body and disposed between the evaporator outlet port and the suction line port; a valve disposed within the valve body, the valve controlling a flow of refrigerant from the liquid line port to the evaporator inlet port; a diaphragm separating a charge chamber and a pressure chamber where a pressure differential between a charge chamber and a pressure chamber controls the positioning of the valve; a restriction flow passage located to provide fluid communication between the sensor chamber and the pressure chamber and configured to limit a flow rate from the pressure chamber to sensor chamber, thereby slowing the opening of the valve resulting in a reduction of noise generated following a startup of a compressor; and a check valve fluidically coupled between the sensor chamber and the pressure chamber for allowing fluid flow from the sensor chamber to the pressure chamber and blocking fluid flow from the pressure chamber to the sensor chamber.