The object is to determine a suitable stop timing of dry cleaning operation in a dry cleaning method without an oil-soluble surface-active agent. Contamination level of a pure solvent supplied from a supply tank to an inner drum of a process tank by a supply-side pump is detected by a supply-side RGB...http://www.google.com/patents/US20050091758?utm_source=gb-gplus-sharePatent US20050091758 - Dry cleaning method and apparatus therefor
