GB1215914A - A combined recirculating air classifier and hot air drier - Google Patents

Abstract

1,215,914. Pneumatic classifier. POLYSIUS A.G. 14 Feb., 1969 No. 8265/69. Headings B2H and B2P. [Also in Division F4] A combined recirculating air classifier and hot air drier comprises a classifying chamber 2 in which feed material to be classified is distributed centrifugally by a plate 4 carried by a drive shaft 3 on which is also mounted a fan 5 for generating a classifying air current. A coarse fraction receiving chamber 8 consisting of upper and lower cones 9, 10 is located below the chamber 2. A fines-receiving chamber 7 surrounds the chambers 2, 8 and is in communication with the chamber 2 through the fan 5 and through a louvre 6 so that classifying air can be recirculated from the chamber 7 through the louvre 6 into the chamber 2. Radial guide vanes 12 are disposed in the annular gap between the cones 9, 10 and are surrounded by an annular chamber 14 to which hot air is supplied via an inlet duct 15. Below the chamber 14 the finesreceiving chamber 7 is provided with an air quiescent zone 16 which communicates with the outside through an air outlet 17. In operation, the hot air is guided tangentially into the cone 9 by the vanes 12 so that as it ascends in the chamber 2 it whirls and dries the descending coarse fraction and at the same time separates fine material that still adheres to the coarse particles. From the chamber 2 the cooled hot air together with the classifying air and the entrained fibres enter the chamber 7, a part of the total air being recycled through the louvre 6 into the chamber 2 and the remainder being discharged as exhaust air through the quiescent zone 16 and the outlet 17.