[Er.Pankaj Garg]

Expansion valves
Expansion valves are devices used to control the refrigerant flow in a refrigeration system. They help to facilitate the change of higher pressure of liquid refrigerant in the condensing unit to lower pressure gas refrigerant in the evaporator.
Types.
1. Automatic Exp. Valves
regulates the flow of refrigerant from the liquid line to the evaporator by using a pressure-actuated diaphragm. It maintains a constant pressure in the evaporator.
2. Thermostatic Exp. Valves : uses a valve mechanism to control the flow of liquid refrigerant into the evaporator coil. The flow is controlled by the pressure in the evaporator.
3.Capillary Tubes is a tube with small internal diameter and could be coiled for part of its length. It is installed to the suction line. A filter-drier is sometimes fitted before the tube to remove dirt or moisture from the refrigerant.
4. Float Valves  is actuated by a float that is immersed in the liquid refrigerant. Both low-side float and high side-float are used to control the flow of liquid refrigerant

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