Abstract: A high thermal efficiency multi-wall heat exchange tube is sealed at one end and has the gap between the tube walls filled with a silicon liquid oil that is nontoxic, has a boiling point above that of water, and increases heat transfer efficiency between the inner and outer walls of the tube. The liquid oil is inserted into the gap between the tube walls by placing the tube into a fixture which receives ten tubes simultaneously, heating the tube and the oil, evacuating the gap and inserting oil into the evacuated gap. The fixture includes a manifold connector assembly which is sealingly positioned over the open end of the one or more tubes to provide a manifold connection between the gap of each tube being filled and a source of vacuum as well as a source of oil and a drain. A hydraulic ram facilitates connection and removal of the manifold connector assembly.

Abstract: A tube and shell type heat exchanger providing multi-pass contraflow of two heat exchange fluids includes a cylindrical outer shell, a modular baffle assembly guiding a shell fluid, a plurality of multi-wall tube sets and a pair of opposed end assemblies. A fixed end assembly fixedly receives one end of the tube sets and provides manifolding for directing multi-pass tube fluid flow through the tube sets. An opposite, floating end assembly slidably receives and seals floating tube ends to accommodate temperature induced expansion and contraction. The floating end assembly also provides manifolding for directing the multi-pass tube fluid flow through the tube sets. A triple wall tube set may be employed to provide extra protection against contamination of heat exchange fluids.

Abstract: A tube and shell type heat exchanger providing multi-pass contraflow of two heat exchange fluids includes a cylindrical outer shell, a modular baffle assembly guiding a shell fluid, a plurality of multi-wall tube sets and a pair of opposed end assemblies. A fixed end assembly fixedly receives one end of the tube sets and provides manifolding for directing multi-pass tube fluid flow through the tube sets. An opposite, floating end assembly slidably receives and seals floating tube ends to accommodate temperature induced expansion and contraction. The floating end assembly also provides manifolding for directing the multi-pass tube fluid flow through the tube sets. A triple wall tube set may be employed to provide extra protection against contamination of heat exchange fluids.

Abstract: A preheater system for using thermal energy available in a refrigeration cycle to heat potable water disposes a double-walled coil having an internal vent path within a water filled tank. Superheated refrigerant is passed through the coil downwardly between an inlet and an outlet. Liquid condensed within the coil accumulates in the bottom of a trap from which it is forced upwardly into a receiver tank and then returned to the refrigeration system. If excessive cooling develops, a pressure responsive valve shunts incoming superheated gas into the receiver tank to return to the selected operating range.