In a preferred embodiment, refrigerant together with oil, water and any other contaminants is drawn off from a high pressure refrigeration system. The drawn off refrigerant is reduced in pressure and serially, the oil is removed, the water is removed and the amount of water and acid present is deter...http://www.google.com.hk/patents/US4923806?utm_source=gb-gplus-share專利 US4923806 - Method and apparatus for refrigerant testing in a closed system
