Patent ID: 7444761

Claim:
A method of treating an object in a closed solvent processing system, said system including a processing chamber, said object being disposed in said processing chamber, said system further comprising a process fluid supply system in communication with said processing chamber, said solvent comprising a flammable solvent, said method comprising the steps of: sealing the process fluid supply system with respect to the chamber; evacuating the process fluid supply system gases to establish a low oxygen environment within the process fluid supply system; introducing an inert gas to said process fluid supply system to return the process fluid supply system to atmospheric pressure; evacuating the process fluid supply system a second time to reduce the oxygen content in the process fluid supply system to create a low oxygen concentration in the process fluid supply system; sealing the processing chamber with respect to the surroundings; applying a negative gauge pressure to the processing chamber to remove non-condensable gases; opening the processing chamber with respect to the fluid supply system and introducing a process fluid into the evacuated processing chamber; processing the object within the chamber while maintaining a low oxygen environment within the chamber; recovering and processing the process fluid introduced into the processing chamber within the closed circuit processing system; sealing the processing chamber with respect to the process fluid supply system; opening the processing chamber with respect to a closed circuit vapor recovery system; recovering and processing the process fluid residual liquid and vapors; introducing an inert gas into the processing chamber for sweeping further process fluids and vapors on the object and within the chamber while maintaining a low oxygen environment within the processing chamber; sealing the processing chamber with respect to a vapor recovery system; introducing an inert gas into the processing chamber to return the processing chamber to atmospheric pressure; and opening the processing chamber and removing the treated object.