Patent ID: 8714359

Claim:
A rotating classifier comprising: a classifier motor; a rotary shaft which is disposed vertically and driven to rotate by the classifier motor; a fixed member which is disposed horizontally so that the rotary shaft passes through the fixed member; support members which are shaped annularly in plan view and disposed below the fixed member and at a distance radially outside the rotary shaft; a large number of rotary classification fins which are fixed to the support members at intervals in a circumferential direction of the support members; and connection members which connect the rotary classification fins to the rotary shaft, the rotary classification fins being rotated by the classifier motor so that a particle group carried by an air flow is classified by centrifugal force of the rotary classification fins; characterized in that: comb teeth-like protrusion portions which protrude toward the fixed member side at intervals along a circumferential direction of the rotary classification fins are provided on top of the rotary classification fins; a first gap is provided between an upper end portion of each of the protrusion portions and a lower surface of the fixed member; a coarse particle passage suppression ring is attached to the lower surface of the fixed member and located radially outside the protrusion portions so that the protrusion portions are surrounded by the coarse particle passage suppression ring; the ratio (Hb/Ha) of Hb to Ha is set to be not larger than 0.2 when Ha is the height of each protrusion portion and Hb is the height of the first gap; and the ratio (Hc/Ho) of Hc to Ho is set to be not smaller than 1.4 when Ho is the length from the lower surface of the fixed member to a lower surface of the coarse particle passage suppression ring and Hc is the height from a lower end of each protrusion portion to the lower surface of the fixed member.