Vortex grinding mill

Claim 1

A GRINDING MILL FOR REDUCING FRIABLE MATERIAL TO A DESIRED RANGE OF FINE SIZES COMPRISING IN COMBINATION, (A) A SUBSTANTIALLY FLAT TABLE MEMBER MOUNTED FOR ROTATION WITHIN A HORIZONTAL PLANE ABOUT A SUBSTANTAILLY VERTICAL AXIS, (B) MEANS TO DRIVE SAID TABLE MEMBER ROTATABLY ABOUT SAID AXIS AT DESIRED SPEEDS, (C) SUBSTANTIALLY RADIAL IMPELLER MEANS CARRIED BY THE HORIZONTAL UPPER SURFACE OF SAID TABLE MEMBER FOR MOVEMENT THEREWITH TO INDUCE ROTARY MOVEMENT OF MATERIAL WITHIN THE MILL, (D) STATIONARY SUBSTANTIALLY CIRCULAR PERIPHERIAL WALL MEANS EXTENDING UPWARDLY FROM SAID TABLE MEMBER ADJACENT THE PERIPHERY THEREOF TO CONFINE AND RETAIN A SEMI-STATIC LAYER OF MATERIAL AGAINST THE SAME AND MEANS SUPPORTING SAID PERIPHERAL WALL MEANS WITH THE LOWER EDGE OF SAID WALL SPACED ABOVE THE PERIPHERY OF SAID TABLE MEMBER TO PROVIDE AN ANNULAR DISCHARGE SPACE OF PREDETERMINED UNIFORM WIDTH FOR GROUND MATERIAL TO PASS THERETHROUGH FROM THE INTERIOR OF THE MILL, (E) A PLURALITY OF BARRIER PLATES, (F) MEANS SUPPORTING SAID BARRIER PLATES STATIONARILY WITHIN SAID CIRCULAR WALL MEANS AT CIRCUMFERENTIALLY SPACED LOCATIONS AND SAID PLATES EXTENDING RADIALLY INWARD THEREFROM, THE LOWER EDGES OF SAID BARRIER PLATES