Gravity-type heat exchanger for treating particulate solid material

Claim 1

IN AN APPARATUS FOR TRANSFERRING THERMAL ENERGY BETWEEN A FLUID AND A SOLID MATERIAL, IN COMBINATION: (A) A FIRST WALL OF SUBSTANTIALLY CIRCULAR CROSS SECTION ABOUT A VERTICAL AXIS; (B) A SECOND WALL OF SUBSTANTIALLY CIRCULAR CROSS SECTION ABOUT SAID AXIS, SAID WALLS DEFINING THEREBETWEEN AN ANNULAR VERTICALLY EXTENDING CONDUIT HAVING A FEED OPENING AND A DISCHARGE OPENING DOWNWARDLY SPACED FROM SAID FEED OPENING, SAID WALLS EACH HAVING A PLURALITY OF SUBSTANTIALLY IMPERFORATE AXIALLY SPACED PORTION AND A PLURALITY OF PERFORATED AXIALLY SPACED PORTIONS, CORRESPONDING ONES OF THE PERFORATED PORTIONS OF SAID WALLS BEING AXIALLY COEXTENSIVE TO CONSTITUTE A PAIR OF PERFORATED PORTIONS, SAID RESPECTIVE ONES OF SAID IMPERFORATDE PORTIONS BEING INTERPOSED IN EACH WALL BETWEEN SAID FEED OPENING AND AN UPPER ONE OF SAID PERFORATED PORTIONS, BETWEEN SAID UPPER PERFORATED PORTION AND A LOWER PERFORATED PORTION, AND BETWEEN SAID LOWER PERFORATED PORTION AND SAID DISCHARGE OPENING;