Patent ID: 6092538
Filing Date: 2000-07-25
Classification: B08B,H01L,Y10S

Abstract:
In a closed recycle system wherein objects to be cleaned in a pressure cleaning vessel are contacted by a high density compressed liquefied gas at its near-critical point state as cleaning solvent is injected from outside said pressure cleaning vessel, contaminants adhered to the objects to be cleaned are dissolved in the high density compressed liquefied gas, subsequent to which said liquefied gas containing said contaminants is then transferred to a recovery tank or a separation vessel and decompressed to reduce the density of said liquefied gas so that the contaminants precipitate for separation, and further the cleaning solvent with the contaminants or impurities removed is reclaimed as a high density compressed liquefied gas and stored for reuse;a method for cleaning and recirculating solvent, wherein a high density compressed liquefied gas existing in near-critical and supercritical state is employed as a solvent, the entire transfer of said solvent is achieved without requiring use of any high pressure generating device by feeding under pressure resulting from a vapor pressure difference between vaporization and liquefaction wherein for said high density compressed liquefied gas the closer to its critical point, the smaller the energy required for vaporization by heating or liquefaction by cooling, and by gravity settling at a set difference in level backed up by the vapor pressure difference, while in the pressure cleaning vessel, the high density compressed liquefied gas is sprayed to the objects to be cleaned for pre-cleaning massive contaminants so that the contaminants can be immediately removed outside the pressure cleaning vessel thereby preventing re-adhesion of the contaminants, and perfect cleaning for a variety of objects to be cleaned is is achieved by forced agitation derived from ultrasonic energy, cavitation affecting the entire solvent by its expansion, and formation of micelles.