Patent ID: 7673827

Claim:
A bowl mill for a coal pulverizer with an air mill section for primary entry of air comprising: a substantially closed separator body having a central axis; a bowl-like grinding table mounted on a shaft rotatable about said central axis and cooperating with a plurality of grinding rolls; and an air mill with an outer wall disposed under the bowl-like grinding table wherein said air mill is provided with multiple entry annular openings tangentially disposed on the outer wall of said air mill, at least two, resulting in better uniformity in air flow around the air mill section and minimizing formation of eddies and vortices, wherein two separate sets of inlet ductings are provided leading to said multiple entry annular openings and the cross sectional area of each opening of the multiple entry annular openings is a fraction of an area required for any given single entry mill output, the fractional area of each opening of the multiple entry annular openings being derived by dividing the area required for the primary entry of air or given mill output by the number of entry annular openings.