| 摘要 |
PURPOSE:To perform a stabilized operation without deteriorating particles size of coal at an outlet of a mill by a method wherein if H denotes a distance from coal layer level to an inner cylinder surface level of a coal classifier, H is requested to adjust and control so that the formula H/D>=0.4 may hold. CONSTITUTION:In the coal classifier hopper 33 pressure taps 37-39 are arranged, besides, a differential pressure between pressure tape 37 and 38, also the same between 38 and 39, are detected by differential pressure detectors 40, 41. Based on the signal detected by these detectors 40, 41, the level of the coal layer 32 of the hopper 33 is decided by a use of an arithmetic unit 42. The distance L, between the highest position of the pressure taps 37 and the lower end level of the inner cylinder 45 of the classifier, also D represents diameter of the coal classifier, then the coal layer level is to be controlled so that the value of ratio L1/D may hold more than 0.4. In case of an increasing load, which causes a higher level of coal seam, then action taken is that a control valve 43 is greatly opened to increase amount of compressed air C into the hopper 33, thereby the coal layer level becomes lower, therefore it is made possible to adjust a position of the coal layer level between the pressure taps 38 and 39.
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