Cushman, Darby & Cushman
Cleaning method and an apparatus thereof
 The cleaning method of the present invention comprises; (a) immersing a material to be cleaned in a mixed solvent contained in the first open vessel, wherein the mixed solvent consists of a chlorofluoro-hydrocarbon with a boiling point of 20.degree.-50.degree. C. and an organic solvent with a boiling point of 50.degree. C. or more higher than that of said chlorofluoro-hydrocarbon and compatible therewith, but not azeotropic therewith, and kept at a temperature within a range between the boiling point of the chlorofluoro-hydrocarbon and a temperature of at least 30.degree. C. lower than the boiling point of the organic solvent, (b) then transferring the material into a boiling liquid essentially consisting of said chlorofluoro-hydrocarbon contained in the second open vessel, (c) and taking out the material from the boiling liquid, (d) wherein, constituting a saturated vapor zone of the chlorofluoro-hydrocarbon by the evaporated vapor from the boiling liquid essentially consisting of the chlorofluoro-hydrocarbon and the mixed solvent in an open container equipped with cooling apparatus in the upper part and holding the open vessels in the lower part, (e) and keeping a constant state of the ratio of the chlorofluoro-hydrocarbon and the organic solvent in the mixed solvent, with a equilibrium of the evaporation of the chlorofluoro-hydrocarbon from the mixed solvent and its absorption from the saturated vapor zone of the chlorofluoro-hydrocarbon, by keeping the temperature of the mixed solvent at a constant temperature. 
Du Pont - Mitsui Fluorochemicals Co. Ltd.
C C
C23G C23G
inventional inventional
Hideaki Michinori
Kikuchi Yokozawa