Effect of screw auger rotational speed on paddy (Oryza sativa L.) grains damage in handling process

In this research, the effect of screw auger rotational speed on paddy grains damage was evaluated. A screw auger with the length of 150 cm, flight diameter of 12.7 cm having standard pitch was constructed for conducting the experiments. The paddy grains damage was determined in terms of broken grains, husked grains, husked-fissured grains, and fissured grains. The results revealed that as the screw rotational speed increased from 100 to 500 rpm, the mass percentage of broken grains and husked grains increased from 0.11 to 0.32%, 0.23 to 0.44%, respectively. Increasing the screw rotational speed from 100 to 500 rpm also caused the number percentages of husked- fissured grains and fissured grains to be increased from 1.65 to 7.42% and 1.0 to 2.5%, respectively. Comparing the results obtained in this study with the results had been previously reported in the case rice grains damage in rice combine cylinder, it was concluded that the extent of paddy grains damage in handling with screw augers is lower than that of rice combine cylinder.