Vertical shaft kiln and method of operation thereof

Claim 1

A VERTICAL SHAFT KILN COMPRISING, IN COMBINATION, AN ELONGATED UPRIGHT OUTER WALL, AN ELONGATE UPRIGHT INNER WALL CONCENTRICALLY PLACED WITHIN THE OUTER WALL AND EXTENDING SUBSTANTIALLY THE LENGTH THEREOF WHEREBY TO PROVIDE A UNIFORM WIDTH ANNULUS THEREBETWEEN, A REFRACTORY LINING ON THE OUTER WALL, SAID INNER WALL AND THE INNER SURFACE OF THE OUTER WALL, SAID INNER WALL HAVING A TOP CLOSURE THEREABOVE, A BOTTOM AIR ACCESS INLET MEANS TO THE TOP SPACE ENCLOSED THEREBY AND A TOP EXHAUST MEANS THEREFROM BELOW SAID TOP CLOSURE WHEREBY TO PERMIT COOLING OF THE SAME BY AIR CIRCULATIO THEREWITH, A PLURALITY OF BURNERS CONCENTRICALLY ARRANGED IN THE INNER AND OUTER WALLS WHEREBY TO DISCHARGE INTO A BURNING ZONE IN SAID ANNULUS THEEBETWEEN, THE BURNERS ON THE INNER AND OUTER WALLS POSITIONED AT SUBSTANTIALLY THE SAME HEIGHT, MEANS AT THE BASE OF SAID ANNULUS TO DISCHARGE TREATED MATERIALS THEREFROM, AND MEANS AT THE TOP OF SAID ANNULUS TO COLLECT AND DISCHARGE COMBUSTION GASES THEREFROM.