Abstract:
The post-harvest unit operations of onion umbels are being carried out manually. Tomechanize this process, the present study was carried out to develop an onionumbels thresher. The developed machine works on the principle of abrasive andimpact actions from rasp bars. Thresher performance was evaluated at different num-bers of rasp bars (2, 3, 4, and 8 numbers), feed rates (25 ± 1, 30 ± 1, and 35± 1 kg/h), concave clearance (6.5 and 7.5 mm), and peripheral speeds (2.5 and 3.3 m/s). At 35 ± 1 kg/h feed rate, 2 numbers of rasp bars, 7.5 mm concave clearance, and2.5 m/s peripheral speed recorded higher threshing efficiency (97.82%) and lowerseed damage (2.08%). The parameters such as the number of rasp bars on thethreshing cylinder, peripheral speeds, concave clearances, and feed rates recordedsignificant effect (p< 0.01) on threshing efficiency and seed damage.
