Thermostatic expansion valve

Thermostatic expansion valve, used primarily in commercial refrigeration and air conditioning, is to clarify the automatic expansion valve (see Fig. 11-3). Bellows or diaphragm reacts to pressure from remote bulb entrusted to a substance similar to the refrigerant in the system. The ball is attached to a suction line close to the evaporator. It is connected to the expansion valve using a capillary tube.

In operation, thermostatic expansion valve maintains the frost line units in the right place, in response to the overheating of the suction gas. Overheating may not be until all the liquid refrigerant in the evaporator was evaporates. Thus, you can get evaporator temperature range by adjusting the superheat control of the thermostatic expansion valve.

The Prime importance of this type of metering device is its ability to prevent flooding back bullet or liquid through the suction line of the compressor. If this fluid is returned to the compressor, it may damage it. The compressor is designed to pump vapor, not liquids.