Patent ID: 7601112

Claim:
A method of treating a substrate in preparation of removing a contaminant contained thereon, the method comprising: providing a centrifuge assembly comprising: a high pressure vessel having an upper region and a lower region; a centrifuge drum disposed within the high pressure vessel, the drum having a central axis, a bottom wall supported by one or more bearings and a perforated side wall; a drive shaft for rotating the drum about the central axis; a stationary, porous centrifuge shield circumscribing the centrifuge drum and forming a separation compartment bounded by the porous shield and the high pressure vessel, the shield adapted to protect an inner surface of the high pressure vessel from potential impact by the rotating drum and/or contents contained therein; a drain port positioned within the high pressure vessel; a fill port positioned within the high pressure vessel; and a high optical sensor located in the upper region of the high pressure vessel and a low optical sensor located in the lower region of the high pressure vessel for monitoring the fluid levels within the high pressure vessel; positioning the substrate containing the contaminant within the centrifuge assembly; supplying the centrifuge assembly with a solvent; pressurizing the centrifuge assembly with carbon dioxide to carbonate the solvent; and contacting the carbonated solvent with the substrate for a selected period of time.