Abstract: The disclosure is directed to a furnace having an elongate, cylindrical, combustion chamber surrounded by a water jacket. Air is blown into the combustion chamber through a loop-shaped distributor having a front bight and a rear bight and parallel horizontal side members. Axially-oriented jet ports are disposed in said bights which direct jets of air toward each other into the center portion of the combustion chamber and chord-oriented jet ports in the side members which direct jets of air downwardly toward the bottom center of the combustion chamber. Fire-tubes are located in the top portion of the water jacket through which the combustion products flow in heat exchange with the water introduced into the water jacket and second fire-tubes in heat exchange with the outlet water lead the combustion gases to a stack. A special band of scraper-deflectors is provided on at least some of the fire-tubes.

Abstract: The disclosure is directed to a furnace having an elongate, cylindrical, combustion chamber surrounded by a water jacket. Air is blown into the combustion chamber through a loop-shaped distributor having a front bight and a rear bight and parallel horizontal side members. Axially-oriented jet ports are disposed in said bights which direct jets of air toward each other into the center portion of the combustion chamber and chord-oriented jet ports in the side members which direct jets of air downwardly toward the bottom center of the combustion chamber. Fire-tubes are located in the top portion of the water jacket through which the combustion products flow in heat exchange with the water introduced into the water jacket and second fire-tubes in heat exchange with the outlet water lead the combustion gases to a stack. A special band of scraper-deflectors is provided on at least some of the fire-tubes.