Enhanced Particle Removal from Inertial Guidance Instrument Parts by Fluorocarbon Surfactant Solutions

Entropic Systems, Inc.'s enhanced particle removal process is a new technology that is being successfully applied to the cleaning of inertial guidance instrument parts. In this process, the part to be cleaned is contacted, under conditions of shear, with a solution of a high molecular weight fluorocarbon surfactant in an inert perfluorinated liquid. It is then rinsed with a volatile perfluorinated liquid which is easily evaporated. The perfluorinated liquids of interest are nontoxic, nonflammable, and environmentally compatible. They do not contain chlorine or bromine, and thus do not present a hazard to the ozone layer. An order of magnitude increase in the rate and extent of fine particle removal from the surfaces of a wide variety of instrument parts is observed when CFC-113 is replaced as the cleaning liquid in an ultrasonic bath by a solution of a high molecular weight fluorocarbon surfactant in an inert perfluorinated liquid. It has also been noted that residual surfactant adsorbed on the cleaned parts is quantitatively removed by subsequent rinsing with clean perfluorinated liquid. A manufacturing scale system which embodies the various elements of the ESI process is presently under construction. In this system, the fluorinated process liquids are recovered and recycled to minimize consumption and fugitive losses, so as to satisfy both economic and environmental imperatives.