This paper aim to develop a low-cost Bambara groundnuts sheller that uses vertical spikes as the shelling mechanism. A vertical spike shelling machine was designed, constructed and evaluated. The Bambara groundnut shelling machine consisted of a hopper, shelling system, frame, motor and power transmission system. The Bambara groundnut sheller used a low-cost shelling mechanism of spikes and shaft system, as it has ability to break different sizes of the Bambara groundnut pods. The prototype was tested for shelling efficiency, percentage mechanical damage of nuts during shelling and machine capacity. The machine was evaluated for shelling efficiency, mechanical damage capacity and cleaning efficiency. The samples used for evaluation were set at different moisture content levels of 6, 15 and 20%. The shelling efficiency of the machine declined from 71.7 to 21.9% as moisture content increased from 6 to 20%. The mechanical damage decreased from 3.66 to 1.46% as the moisture content increase while the machine capacity also declines from 145.6 to 80.1 kg hour-1. The prototype can therefore be viewed as feasible for implementation by small scale farmers.
Key words: Shelling, vertical spikes, efficiency.
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