effect of variety, rotational blade speed and paddy moisture content on performance of a de-awner

paddy de-awning using a de-awner increases the uniformity and flow rate of paddy grains through the orifices of hoppers, bucket elevators and chutes. in this study the effects of paddy variety, rotational blade speed and moisture content on performance of a prototype de-awner machine were investigated. the experiment was conducted in a factorial design with three factors, variety (hashemi and binam), blade rotational speeds (600, 700, 800, 900 and 1000 rpm) and paddy moisture content (9, 11, 13 and 15% wb) in a completely randomized design with three replications. the results revealed that the effect of variety was significant for de-awning efficiency (p<0.05) and cracked grains (p<0.01). the blade rotational speed significantly affected de-awning efficiency, broken, de-husked paddy (p<0.01) and cracked grains (p<0.05). the paddy moisture content significantly (p<0.01) affected de-awning efficiency and broken paddy. the de-awning efficiency increased from 45.33 to 80.33%, broken paddy from 0.59 to 1.14%, de-husked paddy from 0.56 to 1.11% and cracked grains from 5.50 to 7.63% as the blade rotational speed increased from 600 to 1000 rpm. when moisture content increased from 9 to 15% wb, de-awning efficiency decreased from 75.03 to 57.90%, broken paddy from 0.92 to 0.77%, de-husked paddy from 0.81 to 0.74% and cracked grains from 6.73 to 6.10%. the de-awning efficiency of the hashemi varietywas higher than that for the binam variety. the appropriate blade rotational speed was 700-800 rpm and paddy moisture content was 9-11% wb.