Schematic diagram of the modified Vincent three-pass rotary drum dryer showing gas/fluid and material flow directions ARTICLE IN PRESS FRACTIONATION OF ALFALFA INTO LEAVES AND STEMS 457 44.5 50.8 Middle drum 38.1 19.1 12.7 95.3 9.5 Outer drum 41.3 (stationary) Inner drum 12.7 38.1 Note: All dimensions are in mm, also paddle thickness is 3.2 mm