Performance evaluation of motorized and treadle cowpea threshers

Abstract

 A motorized thresher and a treadle cowpea thresher were evaluated in terms of threshing efficiency (%), throughput capacity (kg h^-1), cleaning efficiency (%), mechanical damage (%) and percentage loss (%) for three commonly grown cowpea varieties in Nigeria.  The three varieties were 994, IAR48 and TVX.  The cylinder concave clearances were fixed at 13, 12 and 11 mm based on the major diameter of each cowpea variety.  The investigation was conducted at three levels of moisture contents (12.5%, 15% and 17% wet basis).  Evaluation results indicated that for motorized thresher threshing efficiency varied from 71.4 to 82.86%, 73.56 to 87.14% and 77. 63 to 88.57% while for treadle thresher threshing efficiency varied from 20.50 to 24.29%, 21.50 to 25.71% and 25.05 to 28.57 for 994, IAR48 and TVX varieties respectively.  The highest cleaning efficiency of 80.77% was obtained at 610 r min^-1 for 994 cowpea variety for motorized thresher.  Least damage of 6.00% and 7.5% were observed at 405 and 406 r min^-1 for IAR48 and 994 varieties for motorized and treadle threshers respectively.  A throughput capacity of 66.06 kg h^-1 was obtained at moisture content of 12.5% wet basis and 405 r min^-1 while throughput capacity of treadle thresher was 55.51 kg h^-1 at moisture content of 17% wet basis and 610 r min^-1.

Keywords: cowpea, mechanical damage, moisture content, threshing efficiency, variety