GB934423A - Apparatus for classifying solids - Google Patents

Abstract

934,423. Separating solids. POLYSIUS G.m.b.H. Nov. 4, 1959 [Nov. 7, 1958], No. 37464/59. Classes 23 and 117. Solids entrained in a gas stream are separated according to grain size and specific gravity by decelerating the stream in a diffuser 1, Fig. 1, the finer particles being decelerated by the decelerating stream more than the coarser particles, and then deflecting the gas stream to carry away the slower moving finer particles and allow the faster moving coarser particles to continue. The gas stream may be deflected either by a second air stream as indicated at 2 or by a suction fan. The diffuser may be vertical or horizontal. As shown in Fig. 4, a diffuser is of annular conical shape, material to be classified is introduced at 7 and air at 8, deflection of the air stream may be induced by the suction of a dust separator connected to a chamber 10 and there is an adjustable baffleplate 14 to improve the fineness of separation. The diffuser walls may be interconnected by spiral deflector walls, alternatively the airsolid mixture may be blown into the diffuser tangentially. In a further embodiment, similar to that shown in Fig. 4, the diffuser rotates about its cone axis and centrifugal force aids the separation. Fig. 7 shows a diffuser 6, which may be designed to rotate, and indicates a deflecting air stream from between walls 12 and 13. The diffusers may be divided by partitions 5, e.g. as shown in Fig. 3, so that the angle of divergence of the component diffusers will be lessened. Another diffuser comprises a pair of circular discs, the material and air entering between them at the centre and issuing from the rims. A curved divergent duct forms a further diffuser. The separating efficiency is determined by controlling the volume of entraining gas and, if the diffuser rotates, by varying its speed of revolution.