GB1101100A - Fine particle classifier - Google Patents

Abstract

1,101,100. Seals. MICROCYCLOMAT CO. 15 Dec., 1966 [29 Dec., 1965], No. 56303/66. Heading F2B. [Also in Division B2] In a vertical classifier for dry pulverulent material of the kind described in Specifications 923,331 and 926,290, separated coarse particles contained in an annular discharge chamber 43 are prevented from contaminating separated fine particles contained in a discharge chamber formed by the interior of a fan housing 12 by means of an annular pneumatic seal chamber 85 and of a barrier disc 88 extending from the classifier rotor for rotation in the chamber 85. The rotor includes a flanged ring 35 carrying the disc 88 on the lower surface of its flange and, on the upper surface thereof, a segmental ring 41 carrying vertical radial blades 42, which cause centrifugal discharge of the coarse particles. The chamber 85 is bounded by upper and lower plates 81, 86 which extend into close proximity to surfaces of the ring 35 which are formed with one or more annular grooves 89 providing further pneumatic sealing by setting up eddy currents in the air flow drawn from the seal chamber 85 into the chamber 43 and the interior of the fan housing 12. The annular grooves could alternatively be formed on the surfaces of plates 81, 86. Air enters the chamber 85 through an annular slot 87. In operation of the classifier, reduced air pressure is created in the chamber 43 by rotation of the blades 42 and in the interior of the housing 12 by virtue of the rotation of pegs or rods 37 which support the ring 35 and due to a suction source connected to the fan housing. Any coarse particles accidentally escaping from the chamber through the space between the plate 86 and the ring 35 fall on the disc 88 and are thrown centrifugally outward through the air inlet slot 87 without the possibility of being drawn into the interior of the housing 12.