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Expansion Valve

Expansion Valve


Expansion vales:- Expansion Valve is device is used to make expansion of refrigerant and decrease the temperature of refrigerant. Expansion Valve are the one type of regulator through which refrigerant passes. At the bottom of expansion valve expansion adjustment nut is provided The position of adjustment nut may be changes as per valve design.If  we tightened that bolt high expansion will get us and temperature of refrigerant will highly decreased due to high expansion.If we loosed that nut low expansion will happens .When refrigerant pass through the valve,then pressure drop happens from high pressure to low pressure.Due to sudden Drop of pressure, temperature also decreases of the refrigerant.

Types of Expansion valve


Manual Operated Expansion valve:-
These values were used for CO2 gas refrigeration installation where compressor started and stopped by watch-keeper.The compressor was started at expansion valve open position.Expansion valve then closed to bring up pressure on condensing side until the condensing or saturation temperature for the pressure was five or six degree.
  Manual Operated Expansion valve have a disadvantage of being unresponsive for the changes in load and must be adjusted frequently.

Thermostatic Expansion valve

These values are similar in general design to automatic valve.But having the space above bellow or Diaphragm and filled with liquid refrigerant used in main system and connected with capillary tube to a remote bulb.This bulb is connected in close contact with the suction line at the outlet of the evaporator and it responsive to changes in refrigerant vapour temperature at this point.



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