Improvements in and relating to apparatus for the thermal decomposition of sawdust

摘要

879,316. Apparatus for producing smoke from sawdust. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Sept. 10, 1958 [Oct. 29, 1957], No. 33737/57. Addition to 781,591. Class 81 (1). In an apparatus for producing smoke from sawdust according to the parent Specification, the sawdust is maintained as a fluidized bed at the base of a diverging chamber by means of a gas, e.g. air which is supplied through one or more openings in the chamber wall at the lower end. The chamber may be of the forms shown in Figs. 1 and 2, i.e. it may be an inverted, truncated cone with an angle of divergence of about 11 degrees or it may diverge more rapidly, e.g. at about 20 degrees at the lower end where the bed is maintained and the angle decreased further up to about 5 degrees. The lower end may include an escape pipe 15 and 15a for particles too heavy to be fluidized and an additional gas supply tube 16 and 16a may be incorporated within it. The gas enters through one or more openings 14 and 14a in the chamber wall or preferably through an annular port which may be adjustable as shown in Fig. 3. The gas may be pre-heated by passing through a heating chamber 31 in Fig. 1 fitted with baffles 28 and a heater 29, the chamber being disposed about the part of the decomposition chamber 12 and 12a which holds the bed, the whole being lagged. The sawdust may be introduced through the side of the decomposition chamber or preferably may be introduced in the gas stream through the pipe 26 in Fig. 3. Specification 862,837 also is referred to.