Experimental Performance Evaluation of the Effect of Rotary Sifter Speed on the Product Quality, Purity and Recovery of Continuous Mung bean Thresher using a Variable Frequency Drive

The experimental performance evaluation of the effect of rotary sifter speed on the product quality, purity and recovery of continuous Mungbean Thresher was performed to address the problem in the quality, bean recovery and purity of the existing traditional design. To improve recovery of the output during sifting process, the products are enclosed in a rotating perforated horizontal rotary sifter. To easily control the rotational speed of the sifter, a variable frequency drive was installed to the electric motor. At the usual moisture content ($12 \%$) of the mung bean with pods, machine was tested using three different sifter speed ($146 \text{rpm}, 97 \text{rpm}$, and 73 rpm). Analysis of the results showed that the machine exhibited acceptable values of all the criteria for evaluation but the machine performed well at 90 rpm sifter speed. At this speed, the machine exhibited a $61.5 \%$ shelling recovery with $98 \%$ bean purity and sieving capacity of $900 \text{g} / \text{min}$. It was also observed the higher rotational speed of the sifter produces more output efficiency but also more breakage and low purity while running the sifter at a lower rotational speed results to less breakage, higher purity but low output efficiency.