Heat exchanger utilizing products of combustion as a heating medium

Claim 1

IN A FUEL FIRED HEAT EXCHANGER, A SHELL HAVING AN INLET FOR COMBUSTIBLE FUEL AT ONE END THEREOF, AN ANNULAR PARTITION IN SAID SHELL FORMING AN INNER COMBUSTION CHAMBER AND AN ANNULAR OUTER HEAT EXCHANGE CHAMBER, SAID INLET FOR COMBUSTIBLE MATERIAL COMMUNICATING WITH SAID INNER COMBUSTION CHAMBER, SAID ANNULAR PARTITION HAVING OPENINGS THEREIN NEAR THE END OF THE SHELL REMOTE FROM SAID FUEL INLET, A PLURALITY OF SUBSTANTIALLY U-SHAPED TUBES IN SAID SHELL AND HAVING THEIR INLETS AND OUTLETS AT THE ENDS OF THE SHELL REMOTE FROM SAID FUEL INLET, THE BENDS OF SAID TUBES EXTENDING THROUGH SAID ANNULAR PARTITION WHEREBY ONE LEG OF EACH OF THE TUBES WILL BE LOCATED IN SAID INNER COMBUSTION CHAMBER AND THE OTHER LEG OF EACH TUBE WILL BE LOCATED IN THE OUTER ANNULAR HEAT EXCHANGE CHAMBER SAID SHELL HAVING AN OUTLET FOR GASES OF COMBUSTION THEREIN, SAID OUTLET OPENING INTO SAID HEAT EXCHANGE CHAMBER ADJACENT TO THE END OF THE SHELL REMOTE FROM SAID OPENINGS IN SAID ANNULAR PARTITION.