Chemical recovery furnace with high-temperature superheater

Claim 1

IN A SYSTEM FOR RECOVERING CHEMICALS AND GENERATING AND SUPERHEATING STEAM FROM THE COMBUSTION OF BLACK LIQUOR OF WOOD PULP MILLS, THE COMBINATION OF A SMELTER FURNACE HAVING AN OPEN TOP AND PROVIDED WITH MEANS FOR SPRAYING THE BLACK LIQUOR INTO THE FURNACE INTERIOR AND FOR BURNING SAME IN THE LOWER PORTION THEREOF, A SEPARATE SECOND FURNACE PROVIDED WITH A BURNER FOR FIRING A SEPARATE FUEL, A FLUE CONNECTING THE OFFTAKE OF SAID SECOND FURNACE WITH SAID SMELTER FURNACE INTERIOR AT A LOCATION IN THE SMELTER FURNACE WALL ABOVE SAID BLACK LIQUOR SPRAYING AND BURNING MEANS AND SERVING TO CONVEY AND DISCHARGE THE COMBUSTION GASES FROM THE SECOND FURNACE FUEL TRANSVERSELY INTO THE SMELTER FURNACE THEREBY CAUSING MIXTURE OF THOSE GASES WITH THE RISING GASEOUS PRODUCTS WHICH RESULT FROM COMBUSTION OF SAID LIQUOR, A VERTICAL UPPER EXTENSION OF SAID SMELTER FURNACE DEFINED BY GENERALLY VERTICAL WALLS EXTENDING UPWARDLY FROM SAID OPEN TOP OF THE SMELTER FURNACE TO FORM AN UPRIGHT CHAMBER INTO WHICH THERE PASSES THE AFORESAID RISING MIXTURE OF LIQUOR COMBUSTION PRODUCTS AND SECOND-FURNACE FLUE GASES, A STEAM BOILER SUCCESSIVELY ARRANGED WITH RESPECT TO SAID CHAMBER TO RECEIVE FROM THE CHAMBER''S UPPER PORTION THE SAID MIXTURE OF PRODUCTS AND GASES FROM BOTH FURNACES, A FIRST STEAM SUPERHEATER WITHIN SAID UPRIGHT CHAMBER, LOCATED IN MAJOR PART IN THE UPPER PORTION THEREOF WITH THE LONGITUDINAL AXIS OF ITS TUBES DISPOSED GENERALLY VERTICALLY TO SUBSTANTIALLY PARALLEL THE FLOW THEREOVER OF SAID MIXED PRODUCTS AND GASES AND BEING CONNECTED TO SAID BOILER TO RECEIVE DIRECTLY THEREFROM SATURATED STEAM WHICH IN PASSING THROUGH SAID TUBES HAS SUPERHEAT IMPARTED THERETO, A SECOND STEAM SUPERHEATER IN SAID SECOND FURNACE BEING EXPOSED TO THE FLOW OF SAID SECOND-FURNACE COMBUSTION GASES, CONNECTING MEANS BETWEEN THE INLET OF SAID SECOND SUPERHEATER AND THE OUTLET OF SAID FIRST SUPERHEATER WHEREBY THE STEAM FROM SAID FIRST SUPERHEATER IN PASSING THROUGH THE SECOND SUPERHEATER BY WAY OF SAID CONNECTING MEANS HAS ITS TEMPERATURE STILL FURTHER RAISED