Abstract: An apparatus functioning as a high-efficiency water heater. This apparatus passes a combustible mixture of gas and air from an impeller into the hollow interior of a cylindrical gas burner. The combustible mixture flows out through apertures in the cylindrical walls of the gas burner and is burned on a cylindrical flame holder as it emerges; the size of the apertures prevents flash-back of the flames of the combustible mixture into the gas burner. Heat is transferred from the flame to the walls of a cylindrical combustion chamber surrounding the gas burner and the combustion products generated pass to a heat exchanger comprising a vertical riser and a downwardly extending helical section which ensures maximum heat transfer to water in a tank surrounding the combustion chamber and heat exchanger. Hot water is discharged from the tank as needed for domestic uses and to another heat exchanger in an air heating duct.

Abstract: An apparatus is described capable of functioning as a high-efficiency water heater. This apparatus passes a combustible mixture of gas and air from an impeller into the hollow interior of a cylindrical gas burner. The combustible mixture flows out through apertures in the cylindrical walls of the gas burner and is burned on a cylindrical flame as it emerges from the gas burner; the size of the apertures prevents flash-back of the flames of the combustible mixture into the gas burner. Heat is transferred from the flame to the walls of a cylindrical combustion chamber surrounding the gas burner and the combustion products generated pass to a heat exchanger comprising a vertical riser and a downwardly extending helical section which ensures maximum heat transfer to liquid in the tank surround the combustion chamber and heat exchanger. The apparatus may be used solely as a water heater or may serve as a combined gas furnace and water heating system.