Grinding characteristics, gravimetric properties and energy constant calculations of dried and roasted dehulled soybean splits

The dried and roasted dehulled soybean splits were conditioned to 3 ± 0.02% (db). These samples were ground with hammer mill having different screen aperture sizes (1.5,1.2 and 0.7 mm) and feed rates (18,14,10 kgh"¹) at constant rotor speed (3000 rpm). The dimensions (major, medium and minor), geometric mean diameter, sphericity, surface area, thousand grains mass and bulk density of dried and roasted soybean sample were found to be 2.03 - 8.3 mm and 2.12 - 9.13 mm, 5.15 mm and 5.74 mm, 53.18% and 53.28%, 78.39 mm² and 95.11 mm²,46.78 g and 46.01 g, 601.66 kg m"³ and 484.58 kgm"³, respectively. The size reduction ratio and grinding effectiveness was maximum at 18 kg h"¹ feed rate and 1.2 mm screen aperture size. The specific energy consumptions and power consumption decreased froml52.06 kJ kg"¹ to 15.36 kJkg"¹ and 69.12 kJ kg"¹ to 15.36 kJ kg"¹; 1612.8 W kg"¹ - 1267.2 W kg"¹ and 1382.4 Wkg"¹-1267.2 W kg"¹ with increased feed rate (10 kgh"¹ -18 kgh"¹) for screen aperture size (0.7 mm-1.5 mm) for dried and roasted soybean sample, respectively. Also, the energy constants values showed a decreasing trend with feed rate and screen aperture size range