GB255079A - Improvements in or relating to the heat treatment of spent bone char and similar damp granular materials - Google Patents

Abstract

255,079. Burroughs, C. W. July 8, 1926. Retort and like furnaces; discharging. - A furnace which may be used for drying, heating :and finally cooling spent bone-char or other damp granular material comprises an annular shaft divided into drying, heating and cooling sections 61, 62 and 63 and formed between an internally heated inner shell 6 and spaced bevelled rings 12, 22 enclosed within an outer casing 15. The beating section 62 which is preferably lined with fire-brick 620 is heated by means of a burner 8, the combustion gases rising between baffles 612 in the drying zone 61. Between the latter and the casing 15 air is circulated, air inlet 16, Fig. 1, and outlet 17, being provided. The combustion gases leave the inner shell 6 through a pipe 60 and are passed to a flue 9 either directly or indirectly by way of the heating zone by means of a pipe 92 so as to provide an inert atmosphere for the heated char. Air may be introduced into the heating zone through pipes 70 when decarbonization of the bone-char is desired. Surrounding the cooling zone is a jacket 32, water entering at 36 and leaving at 37. Below the water jacket and secured to a girder 53 is a section 41 having a bevelled edge 42 and between this and a corresponding edge of a ring 43 which closely fits the lower section 63, the char is discharged. Means are provided for raising and lowering the ring 43, consisting of bolts 45 having straps 46, 46 mounted on eccentrics on shafts 47, 47. A thermostat 81 connected with a fuel valve 80 permits of temperature control. The lowest section 63 is supported on a ball-bearing base 66 and the section 61 has a bearing upon the top section 64 which is fixed, thus enabling the inner casing 6 to be rotated by means of gearing 67.