Burner construction

Claim 1

IN A HEAT TREAT FURNACE HAVING TOP AND BOTTOM WALL MEANS DEFINING A TREATING SPACE THEREBETWEEN, A SUBSTANTIALLY CYLINDRICAL RADIANT TUBE DISPOSED INTERIORLY OF SAID FURNACE AND TRAVERSING SAID TREATING SPACE, UPPER AND LOWER HOLLOW ELEMENT HAVING ANNULAR INNER WALL SURFACES REGISTERING WITH SAID TUBE AND CARRIED BY SAID WALL MEANS TO SUPPORT SAID TUBE THEREBETWEEN, MEANS DEFINING A SEALANT CHAMBER DISPOSED EXTERIORLY OF SAID TREATING SPACE AND SUPPORTED BY SAID BOTTOM WALL MEANS TO SURROUND SAID LOWER HOLLOW ELEMENT, MEANS FOR SUPPLYING A COMBUSTION MIXTURE TO THE TUBE FOR COMBUSTION THEREIN, MEANS FOR SUPPLYING ADDITIONAL COMBUSTION-SUPPORTING FLUID TO THE LOWER OF SAID HOLLOW ELEMENT BENEATH THE BOTTOM WALL MEANS AND MEANS FOR FLOWING SAID ADDITIONAL FLUID TANGENTIALLY OF THE ANNULAR INNER WALL SURFACE OF SAID ELEMENT FOR TRAVEL THERETHROUGH IN A HELICAL PATH TO MAINTAIN SAID LOWER HOLLOW ELEMENT AND SAID SEALANT SPACE AT A TEMPERATURE SUBSTANTIALLY LESS THAN THE TEMPERATURE INTERIORLY OF SAID FURNACE.