Automatic expansion valve

Auto-expansion valves control the flow of liquid in response to pressure suction units operating on its diaphragm or bellows (see Fig. 11-2). When the valve is opened, the liquid passes the refrigerant in the evaporator. The resulting increase in pressure in the evaporator closes the valve. Meanwhile, compressor, pulling gas from the coil, reducing the pressure. This decrease in pressure allows the expansion valve to open again. In operation, the valve is never closed. Needle floats only benches and opens wide calls when the device for cooling. When the computer is turned off, the pressure building in rolls expansion valve is closed until the device switches on.