Patent ID: 8151701

Claim:
An apparatus for producing a surface-treated granular product comprising a cylindrical retainer having a plurality of retaining sites for retaining each granule of a granular material travelling along an inside face of the retainer, an abrading tool having a number of elongate flexible abrading segments which are disposed to extend radially of a rotary shaft that extends along the central axis of the cylindrical retainer so as to permit the rotation thereof and are each arranged in such a way that a terminal tip thereof touches the surface of each granule of the granular material retained at the retaining site of the retainer while rotating, a raw material supply site for supplying a granular raw material to the cylindrical retainer and a treated product discharge site for discharging a surface-treated granular product from the cylindrical retainer, wherein the retaining sites are provided with a number of small apertures adapted to sustain granules on the retainer inside face between granules to temporarily retain each granule of the granular material travelling along the inside face of the cylindrical retainer so that the terminal tips of the abrading segments touch and press the surface of the granule retained on the retaining site.