Vibratory grinding

Claim 1

A VIBRATORY GRINDING MILL COMPRISING A RESILIENTLY MOUNTED GRINDING CHAMBER HAVING A TOP WALL AND ADAPTED TO CONTAIN GRINDING MEDIA FOR ACTING UPON A CHARGE OF MATERIAL TO BE GROUND, VIBRATORY MEANS CONNECTED THERETO, THE LOWER PART OF THE CHAMBER HAVING INCLINED WALLS BY WHICH ITS AREA IN HORIZONTAL CROSS-SECTION INCREASES UNIFORMLY WITH INCREASE IN HEIGHT, MEANS AT THE BASE OF THE CHAMBER WHERE ITS HORIZONTAL CROSS-SECTIONAL AREA IS SMALLEST FOR INTRODUCING A FLOW OF AIR WHICH WILL CONSEQUENTLY RISE UP THROUGH THE CHARGE AND FLUIDIZE IT, INLET MEANS IN THE UPPER PART OF THE CHAMBER FOR INTRODUCING MATERIAL TO BE GROUND, A DISCHARGE OUTLET IN THE UPPER ZONE OF THE CHAMBER FOR WITHDRAWING AIR AND GROUND PARTICLES OF THE MATERIAL, AND DUCT MEANS SEPARATE FROM SAID INLET MEANS FOR ADMITTING A STREAM OF AIR TO THE UPPER PART OF THE CHAMBER TO STRIKE THE TOP SURFACE OF THE CHARGE OF MATERIAL TO BE GROUND IN THE CHAMBER.