Hollow sheet metal structure

Claim 1

FOR A HIGH TEMPERATURE FURNACE HAVING A WALL PROVIDED WITH A DOOR APERTURE AND HAVING A DOOR FRAME IN SAID DOOR APERTURE, A HOLLOW FURNACE DOOR MOVABLE ON SAID DOOR FRAME FROM AN OPEN POSITION TO A CLOSED POSITION, SAID FURNACE DOOR HAVING: (A) A HIGH TEMPERATURE INNER FACE PLATE DISPOSED ADJACENT SAID DOOR FRAME AND HAVING A MAXIMUM HEAT ZONE, (B) A LOW TEMPERATURE OUTER FACE PLATE OPPOSITE SAID HIGH TEMPERATURE INNER FACE PLATE, (C) CLOSURE MEANS ADJACENT SAID HIGH TEMPERATURE INNER FACE PLATE AND SAID LOW TEMPERATURE OUTER FACE PLATE AND DEFINING WITH SAID HIGH TEMPERATURE INNER FACE PLATE AND SAID LOW TEMPERATURE OUTER FACE PLATE A FLUID CHAMBER, (D) A PARTITION MEMBER DISPOSED IN SAID MAXIMUM HEAT ZONE BETWEEN SAID HIGH TEMPERATURE INNER FACE PLATE AND SAID LOW TEMPERATURE OUTER FACE PLATE AND DIVIDING SAID FLUID CHAMBER INTO A FIRST FLUID COMPARTMENT AND A SECOND FLUID COMPARTMENT, SAID PARTITION MEMBER PROVIDING TWO-WAY STRETCH TO SAID FURNACE DOOR ADJACENT SAID MAXIMUM HEAT ZONE AND REMOVING HEAT FROM SAID MAXIMUM HEAT ZONE TO SAID CLOSURE MEANS, (E) EACH OF SAID FIRST FLUID COMPARTMENT AND SAID SECOND FLUID COMPARTMENT HAVING: (1) A FIRST CONDUIT MEANS CONNECTED THERETO AND ADAPTED TO INTRODUCE A FLUID INTO ONE CORNER THEREOF, (2) A SECOND CONDUIT MEANS CONNECTED THERETO AND ADAPTED TO REMOVE FLUID FROM AN OPPOSITE CORNER THEREOF, THEREBY SWIRLING SAID FLUID THROUGH SAID MAXIMUM HEAT ZONE IN A GENERALLY CIRCULAR PATH BETWEEN SAID CLOSURE MEANS AND SAID PARTITION MEMBER AND SIMULTANEOUSLY REMOVING A PORTION OF SAID FLUID THEREFROM AND RESWIRLING THE REMAINDER OF SAID FLUID THROUGH SAID MAXIMUM HEAT ZONE IN SAID GENERALLY CIRCULAR PATH, (3) A PARTITION MEMBER CONNECTED TO ONE OF THE SAID FIRST CONDUIT MEANS AND SAID SECOND CONDUIT MEANS FOR SEPARATING THE PORTION OF SAID FLUID CARRIED BY SAID PARTITION MEMBER FROM THE REMAINDER OF SAID FLUID IN SAID FLUID COMPARTMENT TO MAXIMIZE SWIRLING AND RESWIRLING OF SAID FLUID.