Method of cleaning workpiece with solvent and then with liquid carbon dioxide
AssigneeAutoclave Engineers, Inc.
InventorsCharles W. Smith, Jr., Larry R. Rosio, Stephen H. Shore
Life of this patent
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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.
Claims12
A method for precision cleaning of a workpiece comprising the steps of:
- placing the workpiece in a pressurizable vessel with a removable lid and within an inner tank open at the top
- supplying a primary solvent to the inner tank which is liquid at ambient temperatures and pressures and which can be rinsed away by carbon dioxide pressurized to at least liquefying pressures without contaminating the interior walls of the pressurizable vessel;
- flushing the primary solvent through the pressure vessel without contaminating the interior walls of the pressure vessel;
- draining the inner tank to remove the primary solvent;
- supplying carbon dioxide to the pressure vessel pressurized to at least liquefying pressures and flushing it through the vessel by withdrawing it from near the bottom of the inner tank;
- recycling the carbon dioxide by passing it through a let-down valve to a liquid/vapor separator and then passing the vaporized carbon dioxide through an adsorption media filter prior to recondensing to a liquid;
- and
- simultaneously withdrawing carbon dioxide from the tank and from a location in the vessel outside of the tank.
A system for precision cleaning out of a workpiece with a cleaning fluid comprising carbon dioxide pressurized to at least liquefying pressures and a primary solvent which is liquid at ambient temperatures and pressures comprising a pressurizable vessel with a removable lid;
- an inner tank open at the top defining a workspace into which the workpiece can be placed, said inner tank positioned within the pressure vessel;
- means to supply the primary solvent to the inner tank without contaminating the interior walls of the pressurizable vessel;
- means to withdraw the primary solvent from the inner tank without contaminating the inner walls of the pressure vessel;
- means to flush the primary solvent through the pressure vessel and then to drain the tank including means to recycle the primary solvent;
- means to supply carbon dioxide pressurized to at least liquefying pressures to the pressure vessel;
- means to flush carbon dioxide pressurized to at least liquefying pressures through the vessel drawing the carbon dioxide from the interior of the tank;
- means to separate the carbon dioxide flushed through the vessel from contaminants by lowering the pressure thereof, vaporizing and repressurizing;
- and,
- means to simultaneously withdraw carbon dioxide from the tank and from a location in the vessel outside of the tank.
Dependencies are inferred from the claim text.