Optimizing Processing Parameters of Concentric Type Rotary Sieve Grader Using Dimensional Analysis

摘要

Using dimensional analysis, various factors influencing the grading efficiency of concentric type rotary sieve grader which was developed for size based grading of in-shell ca-shewnuts were optimized. The grading efficiency was found to increase as the size of the screen perforations became larger. Optimum length of sieve cylinder observed was 1.2 m for a feed rate of 292 kg h~(-1), suggesting further increase in screen length would yield negligible increase in the grading efficiency. Residence time of nuts inside sieve cylinder decreased as the slope increased from 9 to 18° and reduced rotational speed (10 rpm) of the sieve cylinder ensured ample opportunity for the nuts to pass through the sieve perforation due to lesser relative motion between the nuts and cylinder. A prediction equation for grading efficiency of rotary sieve grader relating various dimensionless products was developed. About 71.67 % of the predicted values deviated less than ± 10 % from the observed response.