Expansion valve

An expansion valve is a valve used for different purposes:

Steam engines
A valve used to control the expansion of steam:


 * Expansion valve (steam engine)
 * The best-known of these was the Meyer expansion valve, the invention of Jean-Jacques Meyer

Thermodynamics
A valve used to expand a gas, for thermodynamic cooling purposes in either:


 * Joule-Thomson cooler
 * heat pump

Also
 * Thermal expansion valve, a component in refrigeration and air conditioning systems