Abstract: Apparatus for effecting heat interchange of fluids, at least one of the fluids containing dispersed or dissolved solids, said apparatus having one or more fluids contacted surfaces which are (1) preferentially oil wettable and (2) substantially zero water adsorbent, wherein the contacted surface or surfaces comprise fluorocarbon polymers, preferably FEP fluorinated hydrocarbon resin, and (3) means for supplying oil or the like to said contacted surface or surfaces, to prevent adherence of solids thereto.

Abstract: Heat exchange takes place between two fluids, namely, mineralized aqueous fluid containing dissolved or dispersed solids or mineral salts and a second fluid, in heat exchange apparatus wherein the surfaces to be contacted by the mineralized aqueous fluid are preferentially oil wettable and substantially zero water adsorbent and are continuously wetted with an organic liquid (oil) which is not permanently miscible with the aqueous fluid being treated, whereby adherence of solids or mineral salts contained in the aqueous fluid or solution is prevented. The preferentially oil wettable and substantially zero water adsorbent contacted surfaces are preferably fluorocarbon polymers such as FEP, however, parylene surfaces are effective and substantially zero water adsorbent but are not as satisfactory as fluorocarbon polymers since parylene coatings on metal are not as permanent as FEP coatings and tend to blister under certain conditions.

Abstract: The method of adhering a preformed continuous film of fluorcarbon plastic material to a flat or convex metal surface which comprises heating both the metal surface and a layer of the plastic material superposed upon the metal surface in a gaseous environment of reduce pressure sufficiently to soften the plastic film and bond the same to the metal surface employing multiple steps of heating, bonding and cooling without application of increased pressure to the outer surface of the heated plastic film to form a bonded metal-plastic combination without entrapment of gas. The invention is particularly adapted to the bonding of fluorocarbon plastic material to surfaces of metal such as aluminum, iron, iron alloys, copper, and copper alloys.