Design modification of wheat and barley threshing machine

Wheat and barley provide over two-thirds of the human food in Ethiopia, with grain protein content similar to other cereals. In Ethiopia, barley and wheat research to date has focused mostly on breeding and on improving agronomic practices, Mechanization has not been widely researched; conventional methods of threshing wheat and barley crop is done on the special flat ground called ‘obdi’ which is usually plastered by cow dung. Nevertheless, considerable yield losses are incurred while threshing. The wheat and barley threshing process traditionally is tedious, labor-demanding, and most of the time causes children out of school while harvesting and threshing. Besides this, as the threshing is done on the ground, the quality of the wheat and barley crop is affected as it can become mixed with the soil, sand, and other contaminants. This affects the market value of wheat significantly as wheat becomes polluted by foreign matter, predominantly minute grains of sand and soil, which are not easy to clean and cause discomfort in the consumption of ‘Budena’. Generally, that is why this project focused on developing a complete wheat threshing machine to overcome wheat threshing and cleaning challenges, thereby decreasing tremendous wheat grain post-harvest loss because of the traditional method of threshing and cleaning, due to the lack of sole threshing machine of this Ethiopian golden crop. The thresher was evaluated and tested at drum speeds of 700, 750, and 800 rpm and feed rates of 23, 25, and 28 kg/min using simulation software. A split plot method of experimental design was used and the variables were replicated three times and a total of 27 observations were used to analyze data. The results showed that the minimum total grain losses of 2.706 %, threshing efficiency of 99.250%, and cleaning efficiency of 99.028 were recorded under a drum speed of 750 rpm and feed rate of 23kg/min.