Shaft furnace

Claim 1

IN A SHAFT FURNACE FOR HEAT TREATING A FLUENT MASS OF SOLID MATEWRIAL SUCH AS LIMESTONE, DOLOMITE, MAGNESITE AND SIMILAR MATERIALS INTRODUCED IN THE UPPER END OF THE FURNACE SHAFT AND DESCENDING THROUGH PREHEATING, COMBUSTION AND COOLING ZONES BEFORE BEING DISCHARGED FROM THE LOWER END OF THE FURNACE, SAID SHAFT FURNACE INCLUDING A CYLINDRICAL WALL, MEANS FOR INTRODUCING AIR AT THE LOWER PORTION OF SAID CYLINDRICAL WALL AND THE LOWER PORTION OF SAID COOLING ZONE INTO THE DESCENDING MATERIAL TO FLOW UPWARD THEREIN IN HEAT ABSORBING RELATION THEREWITH, CIRCUMFERENTIALLY SPACED COMBUSTION CHAMBERS DISPOSED IN SAID CYLINDRICAL WALL LOCATED AT UPPER AND LOWER LEVELS IN COMMUNICATION WITH SAID COMBUSTION ZONE LOCATED AT VERTICALLY SPACED POINTS OF SAID COMBUSTION ZONE, BURNER MEANS LOCATED IN EACH OF SAID COMBUSTION CHAMBERS FOR BURNING FLUID FUEL IN SAID CHAMBERS, VERTICAL TUBULAR CONDUIT MEANS COMPRISING A TUBULAR MEMBER CONCENTRICALLY ARRANGED IN SAID SHAFT THROUGH WHICH COOLING AIR AND EXHAUST GASES OF COMBUSTION ARE WITHDRAWN FROM SID SHAFT FURNACE, SECOND CONDUIT MEANS HAVING ONE END CONNECTED WITH SAID VERTICAL TUBULAR CONDUIT AT A POINT ITNERMEDIATE SAID COOLING ZONE AND THE POINTS OF COMMUNICATION OF SAID UPPER COMBUSTION CHAMBERS, A GAS ACCELERATING MEANS HAVING SUCTION AND PRESSURE SIDES, THE OTHER END OF SAID SECOND CONDUIT MEANS BEING CONNECTED WITH THE SUCTION SIDE OF SAID GAS ACCELERATING MEANS, AND DUCT MEANS CONNECTING THE PRESSURE SIDE OF SAID GAS ACCELERATING MEANS TO SID COMBUSTION CHAMBERS, WHEREBY A MIXTURE OF AIR AND COMBUSTION GASES WILL BE SUPPLIED DIRECTLY TO THE COMBUSTION CHAMBERS OF SAID BURNER MEANS IN THE IMMEDIATE VICINITY OF THE FLAME FROM SAID BURNING FLUID FUEL, AND MEANS TO PERMIT THE ESCAPE OF EXCESS EXHAUST GASES AT THE UPPER OPEN END OF SAID CYLINDRICAL WALL SHAFT FURNACE.