DEVELOPMENT AND PERFORMANCE EVALUATION OF AN IMPROVED CASSAVA PEELING MACHINE

Abstract

A cassava peeling machine was designed, fabricated and evaluated. The machine consists of a peeling system which makes use of three set of peeling tools mounted in a peeling chamber. Each peeling tool consists of a hollow cylindrical roller of about 10 cm diameter on which peeling blades were attached at angle less than 30˚ across the length and circumference of the roller. A disc- auger conveyor powered by a reduction geared motor, was mounted to convey the tubers from the inlet point to the tuber collection point of the machine and a peel outlet chute enables separate collection of the peels. The machine was powered with two 1 hp electric motors which powered the peeling system and the auger separately and was evaluated at five peeling tool speeds of 300 rpm, 500 rpm, 700 rpm, 900 rpm and 1100 rpm and two auger speeds of 10 rpm and 20 rpm. The effects of tuber sizes on the peeling efficiency were determined by introducing cassava tubers grouped into three categories; Small, Medium and Large which had mean masses of 120 g, 600 g and 1200 g respectively. The ejected tubers and peels were checked for the proportion of peels on tubers and tubers in peels respectively and the individual weights of these quantities were recorded. Statistical analysis revealed that the speed of rotation of the peeling tool had significant effect on the percentage tuber loss and total efficiency, although the percentage peel retention slightly differs at different cutting tool speed. 500 rpm presented the highest performance efficiency, having efficiency of 87.06 % which was obtained at 10 rpm auger speed and it was also found to be maximally efficient for medium and large tubers. However, the overall peeling efficiency obtained at the two auger speeds was not significantly different at the obtained P value of 0.547. Also, efficiency initially increases with the batch feed from 5-15 kg and start decreasing thereafter.