Apparatus for grinding and uniformizing grains and screen with annular working space for use in the apparatus

摘要

A double screen (42) including a cylindrical screen (18) and a conical screen (23) is attached to an upper casing (3) into which a revolution shaft (11) is inserted and is provided with a supply opening (2). A rotary blade 12 is arranged within an annular space (15) having a nearly V-shaped section between the cylindrical screen (18) and the conical screen (23) so as to rotate keeping a desired gap relative to the respective screen surfaces. Since the annular space (15) having the nearly V-shaped section is spaced apart from the revolution shaft (11), the rotary blade (12) rotates at a high circumferential speed even in the bottom portion of the annular space (15).