Fig. 1From: Energy consumption of two-stage fine grinding of Douglas-fir wooda Schematic of operational mechanism of the rotor impact mill. A: fine particle stream escaping out of the grinding zone through the classifier, B: turbine air classifier, C: shroud, D: coarse particle stream falling back to the grinding zone, E: hammers, and F: rotor. b Schematic of the hammer mill. G: hammer, H: screenBack to article page