GB1004750A - Centrifugal pulverizer - Google Patents

Abstract

1,004,750. Centrifugal pulverizers ; pneumatic separators. BATH IRON WORKS CORPORATION. Aug. 25, 1964, No. 34820/64. Headings B2A and B2H. A centrifugal pulverizer for reducing rock, pigments, clay, &c., comprises a cylindrical housing 20 with a cover 21, a bowl 32 rotatable by a spindle 27 at e.g. 300-450 r.p.m. and an impeller 40 rotatable at a higher speed by a spindle 26 e.g. at 2350-3600 r.p.m.; the spindles may be driven in opposite directions. An annular recess 38 is provided in an impactor ring 34, forming the inclined wall of the bowl, whose upper edge forms with the inner wall of the housing an opening 39, and the bowl has vents 37 in its floor. The casing contains lower and upper stationary cones 45, 57 axially supported by radially-disposed, spaced-apart arcuate, directional vanes 51, which direct large particles of material back to the impeller for further pulverizing. The lower portion of the. lower cone 45 extends down into the bowl, and terminates above a central opening 46 of the impeller, and the lower portion 58 of the upper cone 57 is cylindrical, extends within the lower cone and also terminates above the impeller opening. A vertically, axially-disposed feed tube 23 extends through the cover, and the upper and lower cones to a point above the opening 46 and is surrounded by a concentric outlet tube 22. Classification vanes 55 mounted below the cover 21 and spaced around it adjacent the upper edge of the upper cone, are adjustable from radial positions to positions forming an acute angle with the original radial positions. Air, forced into the housing via a duct 52 by a compressor (not shown), divides into two paths, one 60 upwards through the vents 37, along the inner wall of the bowl, and the other 61 upward along the outside of the bowl and through the annular opening 39 between the upper edge of the bowl and the inner wall of the housing, and then recombines and passes upward along the outer wall of the upper cone inward into the upper cone, then upward and out through the conduit 22. This division of the air stream keeps the housing wall above the bowl clear of clogging particles. The radial position of the classification vanes 55 controls the path of inward flow of air into the upper zone, and the particle size of material carried out of the tube 22. Particle size is also governed by adjustment of a sleeve 56 vertically in the discharge tube 22. In a modification, a double-deck impeller co-operates with an impact ring having two recesses so that particles returning to the impeller via the lower cone are returned to the upper desk and particles fed to the impeller from the feed shoot or returned to the impeller via the upper cone are returned to the lower deck.