GB629916A - Improvements in or relating to grinding mills - Google Patents

Abstract

629,916. Grinding-mills. HARDTMUTH (GREAT BRITAIN), Ltd.. L. & C., and ZUCKERT, R. Nov. 27, 1947, No. 31452. [Class 59] A mill, particularly for grinding a mixture of graphite and water, comprises a cylindrical casing a, having an inner peripheral wall with an arcuate insert q of hard ceramic material, and a cylindrical rotor m mounted on an eccentric-driving shaft n and carrying grinding blocks s which are slidable radially under the action of centrifugal force. The casing is provided with inlet and outlet pipes c and d communicating with chambers e and f which are separated from the grinding chamber by a plate g formed with an inlet passage j and outlet passage k, the latter extending for 20 degrees up to the position where the peripheries of the rotor and casing are tangential to one another, and the former for about 120 degrees as shown in Fig. 3. The operative faces of the grinding blocks have the same curvature as the periphery of the casing, and their leading ends t are of reduced radius as shown in Fig. 2. The eccentric mounting of the rotor causes it to act as a pump so that material is drawn in through the passage j and expelled through the passage k. If desired, this pumping action may be supplemented by positive and negative pressure means operated so that impulses occur when the spaces between adjacent blocks are opposite the entrance and exit passages. The grinding blocks may be pressed outwardly by springs. The ground material may pass to a storage vessel in which it is agitated, and then returned to the mill for regrinding. Alternatively, a number of mills may be arranged in series. The mill casing and/or storage vessel may be water-cooled.