Apparatus for processing coal - Williams Patent Crusher ...
Williams Patent Crusher and Pulverizer Company (St. Louis, MO) ... One such apparatus is shown in the prior patent of Williams U.S. Pat. No. 3,794,251, issued on Feb. 26, 1974. Another related apparatus is shown in Williams U.S. Pat. No. 3,981,454, issued Sept. 21, 1976 wherein segregation of material is effected by use of an air column so that ...