Vapor generator furnace

Claim 1

IN A VERTICALLY ARRANGED FLUID HEATER FURNACE HAVING A TOTALLY UNOBSTRUCTED LOWER CHAMBER ADAPTED TO RECEIVE THE PRODUCTS OF COMBUSTION IN WHICH THE COMBUSTION OF ASH-CONTAINING SOLID FUEL IS SUBSTANTIALLY COMPLETED AT TEMPERATURES ABOVE THE ASH FLUID HEATED FUSION TEMPERATURE, WALLS DEFINING SAID FURNACE COMPRISING A FRONT UPRIGHT WALL HAVING AN OPENING THEREIN AT ONE ELEVATION FOR ADMITTING THE PRODUCTS OF THE COMBUSTION OF ASH-CONTAINING SOLID FUEL AND A SEPARATE OPENING AT A LOWER ELEVATION FOR ADMITTING THE DISCHARGE OF MOLTEN SLAG, MEANS DEFINING A FLOOR OF SAID CHAMBER AT A LEVEL SUBJACENT SAID SLAGE ADMISSION OPENING. SAID FLOOR. HAVING FRONT AND REAR PORTIONS INCLINED DOWNWARDLY TOWARD A SLAG OUTLET FORMED THEREIN ADJACENT SAID FRONT WALL, A REAR UPRIGHT WALL HAVING AN INTERMEDIATE PORTION EXTENDED FORWARDLY IN THE FORM OF A REVERSE ARCH AND DEFINING WITH SAID FRONT WALL A GAS OUTLET PASSAGE FROM SAID LOWER CHAMBER, SAID WALLS INCLUSIVE OF THE LOWER PORTION OF SAID ARCH DIRECTING SAID GASES WITHIN SAID LOWER CHAMBER ALONG A HORIZONTALLY ELONGATED U-SHAPED PATH OF WHICH THE UPPER PASS TERMINATES IN SAID OUTLET PASSAGE, FLUID HEATING TUBES EXTENDING ALONG THE LOWER PART OF THE REAR WALL AND THENCE ALONG THE LOWER SIDE OF THE ARCH, AND FLUID HEATING WALL TUBES EXTENDING UPWARDLY ALONG SAID FRONT WALL AND THENCE AS A SCREEN ACROSS SAID GAS OUTLET PASSAGE TO SAID ARCH AND THE REAR WALL.