GB176834A - Improvements in furnaces for producing chemical changes - Google Patents

Abstract

176,834. Woodall, Duckham, & Jones (1920), Ltd., and Duckham, Sir A. M. Oct. 14, 1920. Charging and discharging; tunnel kilns; muffle furnaces; gases, supplying.-An annular muffle kiln, a portion of which is shown developed in Fig. 2. is charged and discharged, without interrupting the operation of the conveying-platform g<0>, through gas-tight devices, the muffle being thus completely closed. The kiln walls are supported on columns y by girders d, the space between the girders d being closed at the bottom by plates d<1> having equiangularly-spaced pockets d<2> containing the supporting-rollers e for the annular platform g<0>, which is provided on its underside with a rack f<1> meshing with a driving- pinion f<2>. The upper surface of the platform g<0> is convex to correspond with the roof curvature and the depth of the bed of material thereon is regulated by an adjustable scraper g<2> carried by the shoot g<1> which supports the charging-device g. The arrow indicates the direction of rotation. The charging-device is immediately preceded by a discharger comprising a bucket conveyer o, a casing n carrying a scraper n, and a helical conveyer which receives the material from the buckets and delivers it into a gas-tight discharging hopper. Air is supplied to the combustion space at o and flows in the opposite direction to the platform, and being thus preheated, and incidentally cooling the material, burns with gas supplied through ports on the side of the kiln remote from the charging-device. The combustion products pass through flues k, c to a central chimney. Gas for promoting chemical change in the material is introduced through ports s into a passage r in which it flows in the opposite direction to the combustion gases, and being thus preheated, is admitted through vertical passages into the muffle where its direction is reversed. The gas escapes through passages u, v. A heat-insulating air space w is provided. The charging and discharging devices are mounted on removable plates x which facilitate inspection. Trucks may replace the annular platform, in which case the material is swept by an inclined scraper over the sides of the trucks to a discharging-shoot.