Patent ID: 7735434
Filing Date: 2010-06-15
Classification: F27B,F27D

Abstract:
1. A multiple-hearth furnace comprising: a furnace wall delimiting a cylindrical space with a vertical axis, said furnace wall comprising an inner surface and an outer surface; a plurality of soles delimiting said hearths within said cylindrical space; at least one rabble arm with a wall scraper configured to recover material that accumulates in the vicinity of the furnace wall, said rabble arm being associated with one of said soles, where it is able to rotate about said vertical axis, and said wall scraper defining, during rotation of said rabble arm, an annular scraped zone on said inner surface of said furnace wall; wherein said furnace wall comprises a plurality of wall cavities which form a succession of access openings in said scraped zone, said wall cavities being configured so that they progressively fill with material through said access opening during rotation of said rabble arm.