Design, Manufacturing and Testing of Composite Type Cylinder Sorghum Thresher

Composite cylinder; Grain damage; Thresher design; Threshing efficiency; Unthreshed grains


January 1, 2024


Background: Sorghum cultivars of widely diverse types of head structures and grain properties are produced in Ethiopia. These require different key threshing actions of various functional elements. But sorghum threshers with cylinder consisting of different functional elements are lacking in the country. 
Objective: The study was aimed to design, manufacture, and test the functionality of a sorghum thresher developed with a composite type cylinder using a selected sorghum variety.
Materials and Methods: Fundamental theories, basic principles of design analysis and methods reviewed from the already published research output were followed to design the thresher. The produced prototype was tested at different levels of concave clearance, cylinder speed and feed rate factors laid in 2x32 factorial design with 3 replications using the sorghum variety of Gubbiye.
Results: The test results indicated increasing mean threshing efficiency from 96.15% to 99.52%, an average cleaning efficiency of 95.43% and an average unthreshed grain loss of 1.42%. Grand mean of 0.77% grain damage was observed with the means ranging from 0.25% to 1.07%. Grains remained with glumes indicated the highest mean of 4.15% at 400 rpm that was reduced to 2.25% at 600 rpm.
Conclusion: The results revealed an average of 98.58% threshing efficiency, grain damage of 0.77%, and 3.16% grains remaining in glumes from the test made on Gubbiye variety. This implies that a designed thresher is efficient which can be used by farmers for threshing grains of sorghum varieties in the country.