Abstract: Apparatus for improving the efficiency of a water heater having a tank, a burner and a flue, the flue being disposed within said tank for evacuation of burned combustion gases therethrough with resulting heating of water in the tank, generally including combustion gas deflector for enhancing heat transfer from the combustion gases through a flue wall and into surrounding water during ignition of the burner.

Abstract: A gas-to-liquid heat exchanger formed by winding circular finned tubing into a helical coil has bare tubing wrapped around the coil such that it nests between adjacent turns of the finned tubing. Fittings at the inlets and outlets of both coils distribute the liquid stream so that a portion flows through each coil. The fan tube coil acts as a cooled baffle which directs the hot gas stream flowing over the finned tubes so that it contacts a greater portion of the finned tube external surface area at high velocity and increases the heat transfer effectiveness. Because the baffle is cooled, its temperature remains close to that of the finned tubing. This protects the baffle and eliminates differential expansion which could cause the baffle to fall off or loosen during operation.

Abstract: A preheater for a conventional gas-fired water heater having an outer container, an inner reservoir, water conduits in fluid communication with the reservoir and openings in the outer container allowing the through passage of hot exhaust flue gas from a conventional hot water tank to have an increased residence time with respect to the reservoir for efficient heat transfer of the hot flue gases. The heated water is fed from the preheater to the hot water tank on demand. The preheater is placed atop the hot water tank to receive the hot flue gases therefrom.

Abstract: A device for heating fluid with the exhaust gases from a furnace or stove includes a coiled fluid conduit mounted within the exhaust conduit and means such as baffles for directing the exhaust gases through and around the coiled fluid conduit. In one embodiment, the fluid in the coiled conduit is water from a cold water source which, after passing through the coil and being heated by the exhaust gases, flows to a water heating tank in a pre-heated condition.

Abstract: This disclosure is directed to a heat exchanger which includes a coil through which a heat exchange medium, such as Freon, is circulated between an inlet and an outlet, the coil defining an interior chamber having a lower chamber portion, means for generating a flame, such as a natural gas burner at a lower end portion of the coil whereby heat is introduced into the interior chamber and rises upwardly therein such that the same might be absorbed by the heat exchange medium for subsequent utilization, and the upper end portion of the heat exchanger being closed preferably by insulation material such that virtually all of the heat introduced into the interior chamber is absorbed during the passage therethrough.