Improvements in or relating to chemical cleaning process and an apparatus for carrying out the process

摘要

PICT:0824474/III/1 Dirty solvent from the cleaning or rinsing steps of a chemical cleaning process for textiles or furs is continuously purified by fractional distillation at such a temperature that the solvent is evaporated while impurities in the solvent remain in liquid or solid form and are precipitated to the bottom of the still for removal, the evaporated solvent being subsequently condensed, and dirty solvent being preheated before entering the still by passage through a heat exchanger heated by hot evaporated solvent which has already passed through the still. As shown, a preferred embodiment comprises a washing drum 10, above which are situated pre-washing tank I and clean solvent tank II, and below which are dirty solvent tank III and final rinse tank IV. Dirty solvent is passed continuously from tank III through heat exchanger 22 to still 19, where the solvent is evaporated and passed to heat exchanger coils 21 where it is partially condensed in heating incoming dirty solvent. The partially condensed solvent then passes to device 29, where it is completely condensed, before passing to 31, where any water present is removed, and thence to tank II. Articles in the drum, which is adapted for spin-drying and for ventilating, and which may be automatically controlled, are initially pre-washed with solvent from tank I, the solvent from this stage thereafter passing to dirty solvent tank III. The main washing process is then carried out with clean solvent from tank II with the possible addition of soap solution, this solvent after use also passing to tank III, after which the articles are rinsed with clean solvent, the rinsings being thereafter passed to tank IV and thence to pre-wash tank I. The articles are then spin-dried, dried, blown off and ventilated.