Patent ID: 7497877

Claim:
A solvent cleaning process of cleaning a non-aqueous solvent used in a dry cleaning process for fabrics, the dry cleaning process comprising consecutive wash cycles for washing respective fabrics batches, the solvent cleaning process occurring independent of the wash cycles and when the solvent fulfills a first predetermined condition, the solvent cleaning process comprising: (a) a basic solvent refining cycle; and (b) a first advanced solvent refining cycle; said basic solvent refining cycle comprising a step of separating the solvent into: (i) a first solvent fraction; and (ii) a second solvent fraction which is less clean than the first fraction, by first reducing a temperature of the solvent below 0 degrees C. and then passing the cooled solvent through a cross-flow membrane filter; said first advanced solvent refining cycle comprising a step of low temperature evaporation of the second solvent fraction at a temperature at least 16 degrees C. below a flash point of the solvent, and then condensing the evaporated second solvent fraction and delivering it to a clean solvent storage container, wherein the first advanced solvent refining cycle is effected independent of the basic solvent refining cycle when solvent to be cleaned fulfils a second predetermined condition.