Abstract: A heat extractor system for a furnace, said furnace including a burner with a chimney that is connected but is normally not in operation. Instead, the furnace is connected to a vent in parallel with the chimney through a draft-inducing arrangement including a water spray in which water is heated and circulated to a point where the heat from the water is utilized. Due to the parallel arrangement of the vent and chimney, if the vent fails to operate, it will function in a fail-safe manner, with the combusted gases from the burner leaving through the chimney.

Abstract: A system is disclosed for recovering heat from high temperature combustion gases escaping from a heater such as for examples a domestic warm air furnace, boiler or the like. The system includes a first conduit leading to a chimney and a second conduit leading to a heat recovery unit which in turn is connected to a vent. A "T" connection interconnects the first and second conduits to each other and to the heater. The heat recovery unit artificially induces a draft in the second conduit which overcomes the natural draft induced in the first conduit by virtue of its connection to the chimney. An accelerator in the T connection increases the velocity of combustion gases flowing past the first conduit into the second conduit.

Abstract: A heat extractor system for a furnace, said furnace including a burner with a chimney that is connected but is normally not in operation. Instead, the furnace is connected to a vent in parallel with the chimney through a draft-inducing arrangement including a water spray in which water is heated and circulated to a point where the heat from the water is utilized. Due to the parallel arrangement of the vent and chimney, if the vent fails to operate, it will function in a fail-safe manner, with the combusted gases from the burner leaving through the chimney.

Abstract: A method and apparatus for efficiently recovering heat from a gas stream such as discharged flue gas. The gas stream is countercurrently contacted with a liquid medium in two stages. A first countercurrent contact stage is between a partially cooled gas stream and cold liquid medium in a bed of packing through which the cold liquid medium flows downwards and the partially cooled gas stream flows upwards, so that a warmed liquid medium and fully cooled gas stream are produced. The second countercurrent contact stage is between the warmed liquid medium derived from the first contact stage and the hot initial gas stream in a plurality of parallel vertically oriented passages. The warmed liquid medium flows downward on the inner walls of the vertically oriented passages as a thin liquid film, while the hot initial gas stream flows upwards within the vertically oriented passages, so that a fully heated liquid medium and the partially cooled gas stream are produced.