Classifier, crushing classifier and pulverized coal combustion boiler

摘要

The classifier includes a housing configured to blow airflow from below into the outer peripheral region of the inner space, a drift portion provided on an inner wall surface of the housing and configured to turn the airflow toward the central axis side of the housing, And an annular rotating portion rotatably provided on an inner circumferential side region of the inner space which is positioned on an inner circumferential side with respect to the outer circumferential side region and configured to classify particles accompanying the air flow. Wherein the annular rotating portion has a plurality of rotating blades arranged with a gap around the rotating shaft of the annular rotating portion, and the outer shape of the annular rotating portion formed by the plurality of rotating blades is such that, at the side of the annular rotating portion, The angle formed by the outer shape of the annular rotating portion with respect to a line segment extending in the horizontal direction from the annular rotating portion toward the radially outer side is 75 degrees or less.