Image Number 8 for United States Patent #7980482.
A thermostatic expansion valve includes a valve body having an evaporator inlet port, an evaporator outlet port, a suction line port, and a liquid line port. A sensor chamber formed within the valve body is disposed between the evaporator outlet port and the suction line port. A valve is disposed within the valve body controls a flow of refrigerant from the liquid line port to the evaporator inlet port. A diaphragm separates 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 is 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 an initial startup of a compressor.