Air classifying apparatus with wear reducing deflector

Abstract

Improvements are disclosed in apparatus for air classifying mineral particles by size. The apparatus is of the type including a vertically oriented flow channel for carrying an upwardly directed air flow stream in which the particles are dispersed and a cylindrical air classifier mounted in the flow channel. The classifier has a cage which is rotatable about a vertical axis and is laterally open to the flow channel. A plurality of spaced vertical rejector blades are mounted about the lateral periphery, and the cage is closed at its lower end by a support plate. An outlet is connected to the classifier interior for withdrawing particles passing radially through the blades for collection; and air drawing device is connected to the outlet for drawing the air stream and particles into the classifier and establishing an upward flow of air and dispersed particles within channel. The improvement prevents or limits damage of the classifier support plate by the abrasive impact of the particles carried by the upward flow. A hollow funnel-shaped deflector is fixedly secured below the classifier with its tip facing downwardly. The deflector is open at its base, and formed thereat into an axially-extending lip, the inside of which surrounds but is slightly spaced from the lateral edge of the face plate. An outward air flow is induced through the space between the support plate edge and the deflector lip. This provides an air seal preventing particles from entering the interior of the deflector where they can interfere with the rotation of the classifier or damage the support plate.