Patent ID: 7267293

Claim:
A high efficiency bowl mill having a substantially closed separator body having an interior surface, a rotatable grinding table mounted for rotation in a first direction within the separator body and upon which pulverization of material is effected, a dam ring provided on the rotatable grinding table so as to extend around the circumference of the rotatable grinding table, a plurality of grinding rolls for pulverizing the material on the rotatable grinding table, and an annular passage formed between the separator body and the dam ring provided on the rotatable grinding table, comprising: an inverted cone mounted within the separator body such that an outlet at a lower end of said inverted cone is positioned with a clearance above the plurality of grinding rolls; a deflector embodying a multiplicity of segments, each one of said multiplicity of segments being supported on the interior surface of the separator body so as to be located between a respective pair of the plurality of grinding rolls and above the plurality of grinding rolls; a mill plow having a leading edge, a trailing edge, an angle of incline and a width equal to approximately half the width of each of the plurality of grinding rolls and positioned on a downstream side of a first one of the plurality of grinding rolls so as to be located close to the dam ring and in the path of the plurality of grinding rolls, and with the leading edge of said mill plow facing in the first direction of rotation of the rotatable grinding table, and said mill plow being operative to loosen any material that is caked on the rotatable grinding table; and wherein said inverted cone is operative to eject material for pulverization from the outlet at the lower end of said inverted cone onto a center of the rotatable grinding table, said deflector is operative to cause an air stream flowing through the annular passage from beneath the rotatable grinding table to be directed toward a center of the high efficiency bowl mill and such that the directed air stream is restricted from entering the outlet at the lower end of said inverted cone thereby causing (i) coarser particles of pulverized material entrained in the directed air stream to lose momentum and to separate from the directed air stream for return to the rotatable grinding table for further pulverization and (ii) material loosened by said mill plow to be entrained in the directed air stream, and the mill plow is attached within the interior of the separator body so that a respective one of the multiplicity of segments of said deflector overlies said mill plow.