The product is fed into the ACM pneumatically. Size reduction is a result of the feed product impacting against the rotating grinding elements and against the stationary liner. At beater tip speeds of up to 140 m/s, fineness values of d97 = 10 µm are achieved. The product becomes entrained in the cooling, conveying and classifying air drawn through the mill by the downstream fan and is routed along the guide vanes of the vane ring.
Characteristic for the ACM is the integrated dynamic classifier. The product/air mixture is distributed uniformly by the guide vane ring to the rotating classifier. Because of the two opposing forces and the different masses of the particles, the product is separated in the classifying zone into a coarse fraction and a fine fraction. The coarse material is rejected by the classifying wheel and returned to the grinding zone for further comminution. The fines pass through the classifying wheel and exit the mill. The cut point is a function of the classifying wheel speed, which can be steplessly adjusted even during operation.