The causes are as follows: 1) the speed of classifier does not match with the vertical roller mill grading particle size required by the material; 2) The air volume of the blower is not appropriate. 3) The classifier blade is worn (too coarse).
Solutions: 1) adjust the classifier speed; 2) If the powder is too coarse, the inlet pipe valve of the blower can be properly turned down when the speed of the classifier cannot be adjusted; If the powder is too fine, the speed of the classifier can be reduced or the classifier can be removed to increase the speed of the blower. 3) Blade wear will lead to coarse powder, so it is necessary to replace new blade.