Abstract: Apparatus for cleaning and drying components, such as electronic or electrical components, by contact with a flammable liquid organic solvent, such as alcohol for example, including a reservoir (24) for a highly fluorinated compound, a heating device (22) for heating the reservoir and evaporating the highly fluorinated compound therefrom, a cleaning chamber (12) containing the liquid organic solvent (21) into which the components to be cleaned are emersed for cleaning, a fluid conduit (25) for conducting highly fluorinated compound vapor from the reservoir (24) to the cleaning chamber (12) to cover the organic liquid (21) in the cleaning chamber and directly heating the organic liquid, cooling coils (13) on which the vapor above the organic liquid condenses in the tank (12). Heavy, largely immiscible condensate sinks to the bottom of the tank (12) and is pumped by a pump (20) through a filter (19) to a gravity separator (14).

Abstract: Ternary mixtures of isopropanol, water and a perfluorocarbon boiling at 30.degree. to 70.degree. C., especially perfluoro-n-hexane, have reduced flammability. They can be used for cleaning purposes.

Abstract: Components, especially of an electronic or electrical type, are cleaned by contact with a flammable liquid organic solvent (21), especially an alcohol. The surface of the solvent is covered with a non-flammable highly fluorinated compound vapor blanket (26), which vapor may also be used to transfer heat to the organic solvent. Both highly fluorinated compound and organic solvent are condensed and re-cycled.

Abstract: A method of leak testing electrical or electronic components, by immersion in an inert liquid at a temperature above 100.degree. C., to detect any bubbles arising from the component, after which the component is removed from the liquid and drained, wherein according to the invention the liquid in which the component to be tested is immersed comprises predominantly perfluoroperhydrofluorene, C.sub.13 F.sub.22.

Abstract: Dielectric, cooling or arc-extinguishing fluids comprise a mixture of tetrachlorodifluoroethane and perchloroethylene, optionally with incorporation of a third component which is preferably trichlorotrifluoroethane. Transformer and circuit-interrupter apparatus containing such dielectric fluids are also described.

Abstract: An electrical circuit interrupting device such as a circuit breaker or switch has openable contacts immersed in a first relatively dense liquid, such as a perfluorocarbon, constituting an arc interruption medium and has a second less dense non-flammable dielectric liquid e.g. a halogenated liquid such as perchloroethylene or trichlorobenzene or carbontetrachloride constituting a coolant forming a second phase above the first liquid.

Abstract: Drying articles by displacement and/or solubilization of water with an organic solvent, by dipping the article into a body of solvent which is made effervescent, the said body of solvent being separated, except at the top and bottom thereof, from a non-effervescent body of solvent by means of a baffle wall which extends from a level above the bottom of the solvent container to substantially the surface level of solvent in the container, whereby a circulation of solvent is set up between the effervescent and non-effervescent bodies, and water is removed from the upper part of the non-effervescent body of solvent.