Apparatus for supercritical cleaning

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. 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. The separator regenerates the carbon dioxide and carbon dioxide gas is then condensed and sent to the storage vessel for reuse.