OPTIMIZATION OF MELKASSA AGRICULTURAL RESEARCH CENTER (MARC) BEAN THRESHER PARAMETERS USING RESPONSE SURFACE METHOD (RSM)

In this study, the Agricultural Research Center of Melkassa examined the performance of a laboratory loop type bean thresher. As a function of different drum speeds (450, 550, and 650 rpm), concave apertures (25, 35, and 45 mm), feed rates (550, 650, and 750 kg/h), and moisture levels (5, 10, and 15%), the extent of grain deterioration, threshing efficiency, and rate of implantation were examined. Utilizing response surface techniques, the experimental design for optimization was developed. The response variables were significantly impacted by each independent variable. With a cylinder speed increase of 7.5 to 10.83 ms-1 , the percentages of grain damaged, threshed, and germination decreased from 45.98 to 47.97%, 96.81 to 99.69%, and 85.75 to 55.98%, respectively. Despite an increase in seed germination, damaged grain and threshing efficiency decreased as the moisture content increased. Grain deterioration and threshing efficiency decreased, however seed sprouting improved in tandem with an increase in feed rate and convex aperture. The cylinder speed of 8.25 ms-1, the concave clearance of 37.4 mm, the feed rate of 672 kg/h, and the moisture content of 11.6% (db) were found to be the ideal parameters. In this case, the ideal ranges for seed sprouting, threshing efficiency, and grain impairment were found to be 3, 98.3, and 84.29%, respectively.