Abstract: A process for the assembly of welded plastic hollow plate heat exchangers in which hollow plastic plates with channels running in one direction are welded at the open edge of the sheets to hollow plastic spacing strips which have at least one closed channel running along the open edge of the hollow plastic plate parallel to the open face of the hollow plastic plate by using a taut hot wire, hot knife, or similar cut off and seal techniques and the heat exchangers made by this process. Further improved ruggedness and strength are achieved by melting together the ends of the spacers and the adjacent closed top of the hollow plates.

Abstract: An energy efficient falling film evaporator having a plurality of substantially vertical and equidistant heat exchange elements made of a synthetic polymeric material. Each evaporating surface is in contact with a liquid spreading means, and each heat exchange element is heated by steam having a condensation temperature slightly higher than the boiling point of the aqueous solution from which water is being evaporated. Steam formed by evaporation of water either is recompressed and reintroduced as heating steam in a single-stage process or is used as heating steam for another stage, operating at a lower temperature and pressure, in a multistage process. Heating steam condenses to fresh water, which is recovered. This process is operated at a lower temperature and pressure, in a multistage apparatus. Heating steam condenses to fresh water, which is recovered.

Abstract: An energy-efficient water evaporation process uses a falling film evaporator having a plurality of substantially vertical and equidistant heat exchange elements made of a synthetic polymeric material. Each evaporating surface is in contact with a liquid spreading means, and each heat exchange element is heated by steam having a condensation temperature slightly higher than the boiling point of the aqueous solution from which water is being evaporated. Steam formed by evaporation of water either is recompressed and reintroduced as heating steam in a single-stage process or is used as heating steam for another stage, operating at a lower temperature and pressure, in a multistage process. Heating steam condenses to fresh water, which is recovered. This process is operated at a low feed rate, preferably below 45 Kg of incoming aqueous solution per linear meter of horizontal width of each evaporating surface, and is capable of providing a 50% fresh water recovery per pass from sea water.

Abstract: A reinforced optical fiber cable comprises (i) an optical filamentary material with a glass or silica core and a lower index of refraction sheath, (ii) a reinforcement comprising at least two polymeric fibers having an elastic modulus above 10,000,000 psi, said fibers being held under tension separate from one another and positioned substantially parallel to the longitudinal axis of the core with substantially zero twist and (iii) a jacket which holds the reinforcement under tension.

Abstract: An optical filamentary material with a thermoplastic optically transparent core and a lower index of refraction sheath is spaced from a protective jacket by a heat shield which thermally protects the optical filamentary material during extrusion and application of a jacketing polymer.

Abstract: A reinforced optical fiber cable comprises (i) an optical filamentary material with a glass or silica core and a lower index of refraction sheath, (ii) a reinforcement comprising at least two polymeric fibers having an elastic modulus above 10,000,000 psi, said fibers being held under tension .[.separate from one another.]. .Iadd.around the sheath .Iaddend.and positioned substantially parallel to the longitudinal axis of the core with substantially zero twist and (iii) a jacket which holds the reinforcement under tension.