GRINDER

PURPOSE:To enhance the production capacity of the overall grinder than heretofore by drastically enhancing throughput of a selector in comparison with the case for introducing the pulverized material to a vibrating screen and sieving it as in the conventional manner. CONSTITUTION:While a dispersion plate 39 is rotated, classification air 34 is introduced into an air introducing port 35 and pulverized material 5 supplied from a preliminary grinder is introduced from an introduction chute 43. Classification air 34 ascends through the inside of a easing 32. The pulverized material 5 is dispersed in the radial direction from the central part of the dispersion plate 39 by centrifugal force and blown up by the classification air 34. At this time, fine powder 11 contained in the pulverized material 5 is accompanied with the flow of the classification air 34 and raised. Then this fine powder is introduced into a cyclone 44 and collected therein and carried to a ball mill. Further coarse powder 9 contained in the pulverized material 5 is not accompanied with the flow of the classification air 34 and falls. This coarse powder is taken out from a segmenting nozzle 37 and returned to the preliminary grinder.