Performance Assessment of a Mechanical Mini-Rice Thresher in Maiduguri, Borno State, Nigeria

Abstract

The thresher is a requisite machine in the production of rice business at present. For a newly constructed rice thresher, evaluating its parameters such as efficiency, capacity, optimum speed of thresher and fuel consumption is essential. In a country where imported rice stands at 70% of what we consume; it is very prudent to increase our local production by motorizing the threshing process. Rice quality is affected by moisture content at harvest and the cylinder speed of the thresher during threshing. The effect of cylinder speed hence the optimum speed of the machine will be working as it is investigated. L50 rice variety was used. A recognized method of calculating efficiency, moisture content, and capacity was adopted. Higher moisture 26.2% (wb) yielded an efficiency of 85.3% while the supplementary tests with moisture content of 16.67% (wb) and 23.37% yielded efficiencies of 90.61% and 89.18%. This result was attained when threshing was done at 890 rpm for both cases. The capacity of the thresher at 800 rpm was 26.01 kg/hr whereas 0.35 l of petrol was used in threshing a unit mass of paddy. The optimum speed of the thresher was 890 rpm. In conclusion, higher efficiency was attained when threshing was done at lower moisture content and higher speed. The efficiency on the other hand would increase if threshing losses are minimized as much as possible. Threshing above the optimum speed would increase the losses hence minimizing the efficiency of the thresher.

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