Design and Development of a Black and Green Gram Thresher

Researchers have tried the existing paddy and wheat thresher for pulse crop and have suggested wide ranging modifications. In this study, an attempt was made to design and develop a thresher for pulse crop especially green and black gram. Design consideration showed that the threshing drum diameter could be 40 cm with an r.p.m of 400. Peg type threshing elements (5.5 cm) were used and staggered at 42° for through impact of the threshing element on the crop. The concave was made of 9 mm x 9 mm square bar laterally spaced at 10 mm with a wrapping angle of 136°. The length of the blower was fixed at 27 cm and the height of the blower outlet was calculated to be 6.0 cm. No-load test did not show slackness and noise of any sort. The power consumption at no load was 0.72 hp. From short duration test, it was found that the threshing efficiency was 95.30 and 94.70 per cent for green and black gram respectively. The cleaning efficiency was comparatively low (78.68%) which needs to be improved by providing a second sieve. The power consumption of the thresher was 1.58 and 1.49 hp for green and black gram respectively for at feed rates of 144 and 139 kg ha⁻¹ respectively.