Method for using high density compressed liquefied gases in cleaning applications

Cleaning equipment using a high density compressed liquefied gas wherein a closed recycle system comprises:

• a pressure cleaning vessel (1) provided with a cleaning basket (2) supported in space within said pressure cleaning vessel for accomodating the objects to be cleaned and a plurality of nozzles (3) to emit a spray of compressed liquid (5) directly to said objects to be cleaned, and atmospheric containers (10) placed over and connected to said pressure cleaning vessel, said cleaning vessel further provided with an agitator consisting of an impeller (11) disposed in the bottom of said cleaning vessel and sound wave generators (12) directed towards said impeller and disposed In the side walls of said cleaning vessel;
• a pressure recovery vessel (14) equipped with means for controlling temperature and placed under and branched from said pressure cleaning vessel (1) for receiving the used cleaning liquid after the cleaning process and having a drain cylinder (16) detachably suspended from under said pressure recovery vessel;
• a high density compressed liquefied gas supply cylinder (18) equipped with means for controlling temperature and placed over said pressure cleaning vessel (1) so as to provide communication with the upper portion of said pressure recovery vessel (14) and storage for receiving the upper vapor therefrom;
• an entrainer vessel (13) disposed and connected halfway the feed line between said high density compressed liquefied gas supply cylinder (18) and said pressure cleaning vessel (1);
• and
• said vessels for supplying and receiving the respective compressed liquid are communicating between the respective upper portions thereof for providing communication between the upper vapor in the respective vessels.

In a closed recycling system wherein objects to be cleaned accommodated in a pressure cleaning vessel are contacted by supercritical fluid injected from outside the vessel through means for providing a supercritical state, aqueous and organic contaminants adhered to the objects to be cleaned are dissolved and transferred into said supercritical fluid, which supercritical fluid containing said contaminants is then transferred to a separation tank and decompressed to reduce the density of the supercritical fluid so that these contaminants precipitate for removal, and further the supercritical fluid purified with these contaminants removed is stored with its density recovered for reuse;

• a method for cleaning and recirculating solvent, wherein a high density compressed liquefied gas existing in both regions of 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 setting 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 is achieved by forced agitation and cavitation affecting the entire solvent by its expansion, which cavitation is secured and continued through recycling of the solvent.

Cleaning mechanism in a supercritical fluid cleaning equipment, said mechanism comprising:

• a pressure cleaning vessel (101) provided with a cleaning basket (102) supported in a space within said pressure cleaning vessel for accomodating the objects to be cleaned and a plurality of nozzles (103) to emit a spray of compressed liquid directly to said objects to be cleaned, said cleaning vessel further provided with an agitator consisting of an impeller (105) disposed in the bottom of said cleaning vessel and sound wave generators (106) directed towards said impeller and disposed in the side walls of said cleaning vessel;
• a pressure recovery vessel (108) equipped with means for controlling temperature and placed under and branched from said pressure cleaning vessel (101) for receiving the used cleaning liquid after the cleaning process and having a drain cylinder (110) detachably suspended from under said pressure recovery vessel;
• and
• a low pressure expansion vessel (112) equipped with means for controlling temperature and placed over said pressure cleaning vessel (101), said expansion vessel providing vapor-phase communication with as well as a recycled supply of liquid phase to the pressure cleaning vessel.