Optimization of operational parameters of multi-crop spikes tooth thresher for threshing black gram

The present study was aimed at optimizing operational parameters influencing threshing of mash or black gram (Vignamungo). Six spikes were arranged helically on cylinder by arranging one spike per row. Concave clearance was kept as 25mm. Peripheral speed (PS) of cylinder and crop feed rate (F) were independent parameters, whereas grain damage, noncollectable losses, sieve overflow, output of thresher, cleaning efficiency and threshing efficiency were dependent parameters. Peripheral speed of 21.9 m/s and feed rate of 1000kg/h was found optimum. At this combination the percent grain breakage was 0.47, percent non collectable losses were 0.51, percent sieve overflow was 1.90, output was 319.2 kg/h, percent cleaning efficiency was 97.80 and percent threshing efficiency was 99.06 respectively.