Design, fabrication and testing of a motorized sorghum threshing machine

Abstract

Sorghum is a very important cereal crop in Uganda mainly grown in the Western, Eastern and Northern regions of the country. Traditionally, sorghum is threshed manually which leads to production of poor-quality grains by farmers. The existing imported threshers have challenges of scarcity of spare parts, high costs, lack of technical support and maintenance difficulties. A locally fabricated sorghum thresher was constructed to address the shortcomings of imported sorghum threshers. The spike tooth cylinder thresher was considered during the design due to its simple design which enabled to maintain the cost and weight of the machine low. The main components of the prototype are the feed hopper, concave drum, motor, fan and a pulley system. A sorghum threshing machine with a capacity of 409kg/hr was developed. The performance of the sorghum threshing machine was tested and evaluated and it was ascertained to have a threshing efficiency of 89.8% and grain damage percentage of 15.4%. The unthreshed sorghum was fed through the hopper into the concave drum containing a rotating threshing cylinder with spike teeth that impact the grain ears with high-speed acceleration, detaching them from their panicles