Performance evaluation of a locally developed rice dehulling machine

Abstract The performance of a locally fabricated rice milling machine at Federal University of Technology, Minna was evaluated to determine the behavior of different paddy varieties at different conditions during milling. The varieties used were: FARO52, Nerica1 and FARO55 which represent long, medium and short grain respectively commonly grown by Nigerian farmers. Ten kilogram of each variety was fed into the machine and milled at burr speed of 900 rpm. The milled rice were collected at grain outlet and examined for milled, unmilled and broken grains. From the performance test carried out, the milling efficiency, cleaning efficiency, input capacity, output capacity and average percentage of head rice yield obtained were 90.22%, 90.2%, 27.3kg/hr, 16.47kg/hr, and 44.2% respectively. Total losses, grain recovery range, capacity utilization, milling index, milling intensity, milling rate, milling recovery and co-efficient of husking were 2.5%, 97.5%, 60.3%, 53%, 0.137kg/hr, 14.8kg/hr, 48.8% and 94.8% respectively. The effectiveness of the milling machine is said to be dependent on the paddy varieties and sizes, paddy conditions, milling duration, speed of burr and operator's skill. The result of this performance evaluation can be used by future research in performance optimization of this machine and of course any rice milling machine. The results can also be used in modeling performance evaluation of any rice milling machine.