Performance Evaluation of an Engine Driven Onion Grading Machine

To replace the traditional way of onion grading mechanism practiced in the Ethiopia, the performance evaluation of an onion grading machine developed and fabricated at Asella Agricultural Engineering Research Center (AAERC) was undertaken. The experimental design used was factorial in a completely randomized design with two factors (three levels of speeds of grading unit (rpm) and three levels of feed rate (kg/min) with three replications). The main and interaction effects of machine operational parameters on grading capacity, grading efficiency, bulb damages, fuel, and energy consumption were studied. The optimum result was obtained when the machine operated at 55 rpm speed of the grading unit and a feeding rate of 15 kg/min. At these operational parameters, a grading capacity of 1488.43 kg/hr, maximum grading efficiency of 96.04%, bulb damage percentage of 1.20%, and fuel and energy consumption of 1.37(ml/kg) and 4.23 W-hr/kg, respectively were obtained. Statistical analysis of the data showed that the combination of grading unit speed and feed rate of the grader had a significant effect on grading machine capacity, efficiency, and percent of bulb damage at p < 0.05. The cost of the grader was estimated to be 20,880.99 ETB with a cost-benefit ratio of 1.00: 9.09. Generally, it can be concluded that this grading machine is simple in design, easy in operation, and found to be suitable for small and medium-scale farmers.