GB946178A - Circulating air classifier - Google Patents

Abstract

946,178. Pneumatic separators. POLYSIUS G.m.b.H. May 25, 1962, No. 20271/62. Heading B2H. A circulating air classifier in which moist feed may be dried by hot air or gas and simultaneously classified, comprises a central gas inlet pipe 1 leading vertically upwards inside the classifier to a gas distributer cone 5 located in a classifier chamber 6 between a rotary distributer plate 3 for the feed and a vane assembly 2, a flow chamber 8 surrounding the chamber 6 and leading to a fines settling chamber 9 being provided, the chamber 9 surrounding a collecting chamber 10 for the coarse particles, and an annular chamber 7 above the vane assembly 2 and surrounding the chamber 6 is also provided, exhaust pipes 11 leading from the chamber 7 to the outside of the classifier, the arrangement being such that, in operation, the feed material is distributed from the rotary plate 3 into the chamber 6 where it is dried and classified by the hot air or gas into a coarse fraction which passes through the vane assembly 2 to the chamber 10, and a fine fraction which is carried upwardly to the chamber 8 wherein it flows downwardly, the gas then being deflected into the chamber 7 by suction applied to the exhaust pipes 11 thereby allowing the fines to settle in the chamber 9. The pipe 1 may have an extension 4, carrying the cone 5, which may be adjusted towards and away from the plate 3 or alternatively the cone may be fixed to the underside of the plate 3. The plate 3 may be perforated to allow some of the hot gas to pass through it. The pipes 11 lead tangentially from the chamber 7 and gas is drawn through these pipes by a fan (not shown). Flaps 12 control the flow of air in the pipes 11, which are of a section preventing fines from settling thereon. Cold air may alternatively be used in the classifier providing the desired drying effect may be obtained.