Determining effects of impeller peripheral area on husking properties of rice [Oryza sativa]

The motion of paddy from the inlet of the impeller blade to the husking board is very much complicated. It is said that the husking process is almost equal to the process of energy consumption, due to the friction between the husk and the impeller blades, and the impact energy due to the collision of paddy to the husking board. Although impact forces mainly influence the husking process, these are also the major cause of damage to the rice. Alternative methods of investigations are necessary to reduce the influence of impact forces on the grains. Theoretical approach was applied to analyze a single grain of rice to find out the longitudinal length effect of the impeller blade in this study. By increasing the peripheral area, the revolutionary speed of impeller blade (rpm) was decreased, and conversely less shock or impact energy was produced for the husking purpose. Using two impeller units with 8. 5 cm and 15. 5 cm radius for this, a comparative evaluation was done for the validation of the theory. Ultimately less damage was found on the rice kernels when a larger peripheral area impeller blade was used even with the same peripheral speed (m/s) of the impeller.