New or improved method and means of cleaning filtering medium employed in the separation of mixtures of liquids, e.g. oil and water, or mixtures of liquids and solids

摘要

268,474. Alexander, H. M. Jan. 20, 1926. Filtering-media; filters having sheet filtering- materials.-Filtering-media, such as felt, paper or textile fabric, charged with oils or fats are cleansed by forcing therethrough a solvent for oils or fats which is of greater specific gravity than water, has a lower boiling point and specific heat than the oil or fat and is substantially non- inflammable. Halogen derivatives of hydrocarbons, particularly trichlorethylene, carbon tetrachloride, tetrachlorethane and dichlorethylene, are suitable solvents. The solvent is afterwards separated from the fat by distillation. The method can be applied to a filter having tubular elements without dismantling- the elements and without emptying the filter. Air or steam may be passed through the elements both before and after the solvent is passed, in the first case to loosen and partiallv remove the oil or fat and in the second case to remove any solvent retained by the filtering-medium.