Abstract: An apparatus and method for controlling the use of carbon dioxide in drying cleaning clothes, garments and other fabrics is disclosed and claimed. The components of the invention include a distillation vessel, a compressor, a warm-up vessel, a cleaning chamber, a condenser, and a carbon dioxide storage tank. A programmable logic controller is utilized to control the apparatus. Several modes of use are disclosed. One mode, the reclaim mode, enables the efficient operation of the apparatus. As the name implies the reclaim mode recovers most of the carbon dioxide gas remaining in the cleaning chamber is removed therefrom.

Abstract: An apparatus for precision cleaning with carbon dioxide includes a pressure vessel having a removable cleaning drum with a sanitized work zone. The sanitized work zone is defined by an impermeable drum body having a removable exit filter to ensure that circulating cleaning fluid does not redeposit contaminants on the parts. The carbon dioxide is maintained in liquid form in the storage vessel, raised above its critical temperature by the preheater, pumped into the pressure vessel to achieve critical pressure, circulated through the work zone for a predetermined period of time, and removed through the let-down valve.

Abstract: A method for precision cleaning of a workpiece with a cleaning fluid comprising liquid and/or supercritical fluid carbon dioxide and a primary solvent which is liquid at ambient temperatures and pressures comprises first placing the workpiece in a pressurizable vessel with a removable lid and within an inner tank open at the top; supplying the primary solvent to the inner tank; flushing the primary solvent through the pressure vessel; draining the inner tank to remove the primary solvent; and then supplying liquid and/or supercritical fluid carbon dioxide to the pressure vessel and flushing it through the vessel by withdrawing it from near the bottom of the inner tank.

Abstract: A method for precision cleaning of a workpiece with a cleaning fluid comprising liquid and/or supercritical fluid carbon dioxide and a primary solvent which is liquid at ambient temperatures and pressures comprises first placing the workpiece in a pressurizable vessel with a removable lid and within an inner tank open at the top; supplying the primary solvent to the inner tank; flushing the primary solvent through the pressure vessel; draining the inner tank to remove the primary solvent; and then supplying liquid and/or supercritical fluid carbon dioxide to the pressure vessel and flushing it through the vessel by withdrawing it from near the bottom of the inner tank.

Abstract: An improved precision cleaning method includes introducing a solvent to a cleaning vessel, placing a workpiece in the cleaning vessel and contacting the workpiece with the solvent during a residence period. The cleaning vessel is then pressurized to a target pressure by adding carbon dioxide to the vessel, and additional carbon dioxide is pumped into the vessel while maintaining the target pressure to flush contents of the vessel. Cleaning may be enhanced by pressurizing to above the supercritical point of the carbon dioxide, and cleaning is further enhanced by application of sonic energy or mechanical agitation.

Abstract: An apparatus for precision cleaning with carbon dioxide includes a pressure vessel having a removable cleaning drum with a sanitized work zone, a separator for regenerating spent carbon dioxide, and pressure and temperature monitoring and control devices to maintain the carbon dioxide in a supercritical state while it is circulated in contact with a part to be cleaned. The sanitized work zone is defined by an impermeable drum body having removable entry and exit filters to ensure that circulating cleaning fluid does not redeposit contaminants on the parts. The separator includes distillation means. The pressure vessel and separator form part of an overall system, including a storage vessel for carbon dioxide, a pump, a preheater, a let-down valve in communication with the pressure vessel outlet, a condenser and a bypass.