R134a: Is internationally recognized as one of the main refrigerant working substances . It does not contain chlorine atom, gives no bad effects against ozonosphere and has excellent safety performances, such as non-toxicity, non-inflammability, non-explosive ability , non-pungency, and non-corrosive ability. It is a colorless gas under ordinary temperature and a colorless & transparent liquid under the pressure of itself. It is often used in the refrigerating systems of auto air conditioners, commercial and industrial purposes, and as the vesicant, it is used to produce the heat-protective material made of rigid plastics, and also to prepare other blend refrigerants, such as R404A & R407C.