PERFORMANCE OF STRIPPER ELEMENT DESIGNS IN LABORATORY TESTING FOR STRIPPER HARVESTERS AT VARIOUS GRAIN MOISTURE LEVELS AND ROTOR SPEEDS

The rice harvester machine (stripper) in Indonesia struggles with high grain losses and low cleanliness. This study examines factors such as comb design, rotor speed, and grain moisture levels contributing to these issues. Using a laboratory testing apparatus, the research evaluates different stripper element designs and rotor speeds at varying grain moisture levels. Data on collected and uncollected grains are categorized as unstripped, shattered, and scattered losses. The experimental design employs a factorial randomized block design with three replications, with percentage losses and cleanliness as dependent parameters and comb type, grain moisture content, and rotor speed as independent parameters. Analysis of variance assesses the significance of each parameter’s influence and their interactions. Subsequent Duncan Multiple Range Tests at α 5% determine specific differences. ANOVA results show significant differences in losses among independent parameters and their interactions. Cleanliness observations also show significant differences among independent parameters. The best comb design is the curved comb type, with the lowest grain losses at 6.34% and highest cleanliness at 97.29%. Operating at a rotor speed of 1.41 m/s (54 rpm) with a grain moisture content of 12%, this design offers improved efficiency for rice harvesters in Indonesia