Abstract
A pedal operated paddy rice winnower for small scale rural farmers was developed to work under the condition of Bauchi state. It was locally fabricated in center for industrial studies (CIS), Abubakar Tafawa Balewa University Bauchi. The whole machine was constructed from steel, angle iron, sheets, bearing, chain and sprockets, shaft, bolts, nuts, and bicycle frame, while design parameters calculated includes shaft diameter (15mm), torsional moment (0.68Nm) and gear ratio (2.66) respectively. The cleaning effect of the winnower is achieved through the cranking of the prime mover (Bicycle) which drives the fan. The machine was developed to be driven by human muscle power through the pedal on the bicycle. The threshed grain with a moisture content of 13.28% (wb) was fed into the hopper manually and the final cleaned grain was collected under the sieve on a collecting pan. From the test carried out on the machine, it indicates that only one person is needed to operate, while it needs the sum of #73,100.00 as an investment cost. On the other hand, the performance test indicates a cleaning capacity of 90 – 100kg/hr of threshed paddy rice, with a cleaning efficiency of 84.04% and a loss of not more than 13.82%. The machine has a great potential in helping to reduce cleaning time and save cost.
Highlights
Rice (Oryza sativa) production is extending to areas which traditionally are not producers of the crops [1]
It indicates that as the feed rate increases, the cleaning efficiency decreases, while the percentage grain loss increases with increased feed rates
He explain the phenomenon as due to the fact that as the feed rate gradually increases, the mass flow across the air current could still allow air to penetrate and flush out unwanted materials up to a point corresponding to minimum grain loss, after which feed rate reached a level that the blanket effect could completely prevent air current penetrating through the material mass flow and more grains are dragged along the sieve and expelled through unwanted material outlet, which gives rise to increase in grain loss after minimum point [8]
Summary
Rice (Oryza sativa) production is extending to areas which traditionally are not producers of the crops [1]. Cleaning and winnowing is one of the important processes done in preparing rice as food. It involves the removal of chaff and other debris from the grain. A good winnowing machine should remove all chaff straw and plant debris with little grain loss. Winnowing removes unwanted materials like straws, chaffs, weeds, soil particles and rubbish from grains. It improves grain storability, reduces dockage during milling, gives good quality milled rice and improves the milling output.
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