US 5,344,493 AGranted

Cleaning process using microwave energy and centrifugation in combination with dense fluids

OwnerDavid P. Jacksoninventor

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Abstract

An environmentally safe process for cleaning substrates used in critical environments with stringent end-product cleanliness requirements in a single process using microwave-energized and centrifuged dense fluids. One or more dense fluids are mixed with one or more chemical or physical agents and are simultaneously subjected to microwave radiation and centrifugal force to remove deeply recessed contaminants from internal and external surfaces of intricately arranged or formulated substrates such as biomaterials, spent activated carbon, elastomerics, surgical aids, or dental implants. Subsequently, cleaned substrates are simultaneously subjected to microwave radiation and centrifugal force under vacuum to remove residual volatile contaminants. Additionally, the cleaned and sterilized substrates are contacted with chemical or physical agents to provide enhanced cleaning and to provide new and improved substrate properties such as increased electrical insulation, conductivity, or biocompatibility. Finally, the entire process is performed on substrates which are prepackaged in semi-permeable membranes, preventing recontamination of the cleaned substrates.

Claims25

Dependent claims

A process for cleaning a substrate containing at least one contaminant, by placing said contaminated substrate in a centrifuge basket in a cleaning chamber, and by following the steps of:

1) contacting said substrate containing said contaminant with a dense fluid at a pressure equal to or above the critical pressure and below the critical temperature of said dense fluid;
2) continuously centrifuging said substrate in said basket;
3) simultaneously subjecting said contaminant contained in said substrate and dense fluid to a high energy source of microwave energy at a frequency of 2.45 GHz;
4) maintaining contact of said energized contaminant on said substrate for a predetermined period of time above the critical pressure and below critical temperature of said dense fluid, wherein a wide range of solvent environments are created wherein contaminant solubility and transport from said substrate is provided to thereby remove said contaminant from said substrate in one continuous process;
and
5) introducing a physical or chemical agent into the dense fluid by injection, solution, or reaction methods and contacting for a predetermined period of time in the dense fluid, in order to cause the precipitation, dissociation, dissolution, or activation of the physical or chemical contaminant in said substrate interstices;
and
6) subjecting said substrate to high vacuum (0.0001 Torr) to remove residual contaminants and excess chemical and physical agents.

5 more elements

Dependencies are inferred from the claim text.