Abstract: A dual direct contact water heater is described and consists of a heater housing having two sections, each section having a water reservoir. One section provides hot water at a high temperature and provides a source of heat exchange to heat an external source of water for commercial use. A burner is provided in the first section to provide the heat source to a packing through which water percolates. The source of water for the first section is the outlet of a heat exchanger whereby water from the reservoir is recirculated in a closed circuit in the first section. Hot gases rising from the first section is directed to a second section which also includes a second packing and a reservoir and it also has a closed loop whereby a second source of hot water, at a lower temperature, is utilized in a closed loop and in heat exchange with a second external source to produce domestic hot water or without heat exchanger to produce hot water for various processes.

Abstract: A gas-fired water heater is comprised of a vertical housing (11) having a circumferential side wall (12), a closed bottom end (13), and a flue (14) connected to a top end portion (15) thereof. A packing (17) of heat exchange elements (18) is supported inside the housing (11) in an uppermost region (19) thereof. A water discharge orifice or nozzle (21) is disposed above the packing (17) and connected to a water supply (22) for releasing water to be heated on the packing. An axial burner (23) is disposed substantially centrally with the housing under the packing (17). A feed pipe (24) is connected to the burner (23) and extends at least partly axially within the housing. A gas-air mixture is fed to the burner (23) through the feed pipe (24). An ignitor device (25) is provided to ignite the burner (23).

Abstract: A direct contact water heater having a hybrid heat source, and its method of operation is described. The water heater is comprised of an elongated vertical tubular housing having a water spray nozzle in an upper end thereof for spraying water substantially uniformly over a top packing of heat exchange bodies. An intermediate space is provided below the packing where external hot recovery gases are admitted into the housing. A burner chamber is provided at the bottom of the housing above a reservoir to provide a primary heat source. Heat from the primary heat source mixes with the hot recovery gases below the packing, and is in counter-current flow with the water percolating through the housing from the packing located at the top of the housing. Two packings of heat exchange bodies may be provided in the tubular housing spaced from one another with the hot recovery gases fed between the two packings and the primary hot gas from the heat source being generated below a lower one of the packings.