GB259389A - Improvements in or relating to furnaces - Google Patents

Abstract

259,389. Trocknungs-, Verschwelungs-, und Vergasungs-Ges., Honigmann, L., and Bartling, F. Oct. 19, 1925. Hearths; tunnel kilns; charging and discharging.-A furnace of the annular rotary hearth type for the heat treatment of pulverulent, pulpy or like material comprises an annular furnace arch a enclosing a space b in which rotates the hearth c, means h, l for continuous charge and discharge of the material and means for applying heat to the charge and heating the uncharged hearth between the discharging and charging points II, I. From the charging pipe h is elastically suspended a hopper h<1> the lower edge of which is in sliding contact with ledges k projecting from the hearth c, a cross beam j preventing the hopper from being carried round with the hearth. Between the ledges k the hopper h carries an adjustable plate i sweeping directly over ribs d on the surface of the hearth to spread the material uniformly. The discharge pipe leads to the intake of a blower m and supports a suction chamber resting on the ledges k so that the treated mateterial is drawn off the hearth together with distillation gases to a separator n, the gases being returned to the furnace by a pipe o. Hot gases are admitted at p and pass out at g heating the empty hearth in the zone III which is shut off from the treating zone IV. Pipes are provided for withdrawing the gaseous products of the distillation &c. from the zone IV, which may also be heated by hot gases passed through channels in the, roof a. The annular hearth c comprises a ribbed metal plate c<1> and an underlying plate c<11> nf fire-brink carried by an annular tank f floating in liquid in a chamber e, the tank being rotated by gearing g<11> and guided by rollers g. Sand or water seals e<1> prevent admission of air above the hearth and the hearth may be cooled by air admitted to the tank f through slits f<1>.