Recuperator

Claim 1

A HEAT EXCHANGER RECUPERATOR COMPRISING A GENERALLY HORIZONTALLY DISPOSED LONGITUDINALLY EXTENDING CHAMBER HAVING LONGITUDINALLY EXTENDING SIDE WALLS; MEANS FOR PASSING HEATING GASES LONGITUDINALLY THROUGH SAID CHAMBER; A STRUCTURE FOR CONDUCTING GASES TO BE HEATED EXTENDING ACROSS THE TOP OF SAID CHAMBER AND COMPRISING UPPER AND LOWER COMPARTMENTS EXTENDING TRANSVERSELY OF SAID CHAMBER WITH A LOWER PARTITION AT THE BOTTOM OF SAID LOWER COMPARTMENT AND AN INTERMEDIATE PARTITION SEPARATING SAID UPPER ABD LOWER COMPARTMENTS; AND A BANK OF DOWNWARDLY EXTENDING ELONGATED HEAT EXCHANGE ELEMENTS OF RECTANGULAR CROSS SECTION SUSPENDED FROM SAID STRUCTURE WITH THE MAJOR AXIS OF THE RECTANGULAR CROSS SECTION OF EACH HEAT EXCHANGE ELEMENT EXTENDING GENERALLY LONGITUDINALLY OF SAID CHAMBER, SAID BANK EXTENDING TRANSVERSELY OF SAID CHAMBER, EACH OF SAID HEAT EXCHANGE ELEMENTS COMPRISING A DOWNWARDLY EXTENDING ELONGATED INNER TUBULAR ELEMENT OF RECTANGULAR CROSS SECTION HAVING AN OPENING AT ITS LOWER END AND AT ITS UPPER END BEING SUPPORTED BY SAID INTERMEDIATE PARTITION IN COMMUNICATION WITH UPPER COMPARTMENT, A DOWNWARDLY EXTENDING ELONGATED OUTER TUBULAR ELEMENT OF RECTANGULAR CROSS SECTION AND FORMED OF HEAT CONDUCTIVE METAL SURROUNDING SAID INNER TUBULAR ELEMENT AND DEFINING THEREBETWEEN A PERIPHERAL SPACE, SAID OUTER TUBULAR ELEMENT HAVING A CLOSED LOWER END AND AT ITS UPPER END BEING SUPPORTED BY SAID LOWER PARTITION IN COMMUNICATION WITH SAID LOWER COMPARTMENT AND HAVING ITS EXTERIOR SURFACE OF METAL AND ESSENTIALLY BARE OF EXTERNAL PROTUBERANCES PROVIDING EXTENDED HEAT TRANSFER SURFACES, AND