GB1027980A - Apparatus for classifying particulate solids - Google Patents

Abstract

1, 027, 980. Classifying solids. POLYSIUS G.m.b.H. Aug. 31,1964 [May 13,1964J, No. 35532/64. Headings B2H and B2P. An air classifier:Fig. 1 (not shown) which is substantially of the type described in Fig. 1 of Specification 934,424, is modified by having the outer tapered wall 1a of the diffuser 11, Fig. 3, bent at its outlet end 1a<SP>1</SP> in a direction towards the separating wall 5 (of the funnel) between the collecting chambers 12 and 13 for coarse or heavy and fine or light particles respectively. This arrangement reduces the surface contact between the main flow of air drawn through the chamber 13 and the air in the chamber 12 thereby reducing the strength of the secondary swirl 15 due to this contact and hence reducing the possibility for the coarse or heavy particles reentering the main flow and of being entrained thereby into the chamber 13. Entrainment of the coarse or heavy particles is further reduced by a guide plate 16 which defines with the diffuser end wall 1a<SP>1</SP> an annular gap 17 through which secondary air, fed tangentially to an annular channel 18, passes and prevents the coarse or heavy particles from entering the chamber 13. The secondary air also cleans coarse or heavy particles which enter the chamber 12 in the direction of the arrow 20 from adhering fine or light particles. The chamber 12 may be extended upwardly as shown by the dotted lines to further reduce entrainment. The funnel 5 is adjustable lengthwise of the classifier.