Soaking pit construction for metal ingots

Claim 1

IN A SOAKING PIT FOR ALUMINUM INGOTS AND THE LIKE, A HEATING CHAMBER HAVING A FLOOR WITH OPENINGS THEREIN WHICH PROVIDE FOR VERTICAL CIRCULATION OF HEATED AIR TO EFFEACT A HEATING ACTION ON ALUMINUM IGNOTS RECEIVED THEREIN, A HEAT EXCHANGER CHAMBER FOR RECEIVING A FLOW OF SUCH GASES AFTER THEY PASS THROUGH THE HEATING CHAMBER AND ARE THEREAFTER RETURNED UNDER PRESSURE FOR REPEATED RECIRCULATORY MOVEMENT THROUGH SAID HEATING CHAMBER, MEANS FOR SUBDIVIDING THE FLOW OF HEATED AIR WITHIN SAID HEATING CHAMBER INTO SUBSTANTIALLY UNIFORM FLOWS SO THAT SUBDIVIDED FLOWS WILL SWEEP UNIFORMLY THE ALUMIMUM INGOTS THEREIN, MEANS FOR COLLECTING SUCH SUBDIVIDED FLOWS AND THEREAFTER DIRECTING THEN TO SAID HEAT EXCHANGE CHAMBER, A PUMP ADAPTED TO CIRCULATE UNDER PRESSURE A HEATED FLOW OF COMBUSTION PRODUCT GASES THROUGH SAID HEAT EXCHANGE MEANS, A BURNER FOR RECEIVING A COMBUSTIBLE FLOW OF FUEL AND AIR FOR GENEATING A HIGH TEMPERATURE FLOW OF GASES FOR CIRCULATION THROUGH SAID HEAT EXCHANGE MEANS, AN EXHAUST FOR REMOVING A PORTION OF THE CIRCULATING COMBUSTION PRODUCT FLOW TO MAINTAIN THE PRESSURE CONDITIONS AT A SUBSTANTIALLY CONSTANT VALUE, AND MEANS PROVIDING AN INFLOW OF AIR AT CONTROLLABLE RATES TOGETHER WITH SAID COMBUSTION PRODUCT GASES TO ESTABLISH THE TEMPERATURE OF THE CIRCULATING PRODUCT GASES.