Development of an Improved Iar Sorghum Thresher.
Abstract
Despite the high of production of sorghum in Nigeria, its threshing and operation remains among the major to farmers especially in the northern of the .
Efficient sorghum threshers are not available to Nigerian farmers.
The prototype thresher developed at the institute for agricultural research (iar) was associated with many problems such as low out capacity, higher scatter loss, and mechanical grain damage.
To solve these problems a modified model was designed, constructed, and evaluated.
The major components modified include feed hopper, cylinder, concave, and shaker.
The machine performance was evaluated at various levels of moisture contents, cylinder speed, and feed rates.
The results showed that threshing efficiency, cleaning efficiency, and throughput capacity of the modified thresher were 99.98, 99.95 %, and 253.96kg/h respectively while those for scattering losses and mechanical grain damage were 5.45 and 3.70 % respectively.
This indicates a percentage increase of 0.98, 6.95, and 56.96% for threshing efficiency, cleaning efficiency, and throughput capacity respectively and a decrease in scatter loss and grain damage of 5.98 and 3.84 % respectively.
The best combinations of the independent variables for optimum operations were 13 % moisture content, 12.67 m/s cylinder speed and 5 kg/min feed rate.
The optimum performance values obtained were of 297 kg/h throughput capacity, while threshing efficiency, cleaning efficiency, scatter losses and mechanical grain damage were 99.8, 99.5, 5.09, and 3.4 % respectively.
Introduction
1.1.General background
Threshing and cleaning operation is a necessary step before processing of grains into flour for domestic or industrial uses.
In addition, annual yield evaluations by farmers are only possible after threshing operations.
The by-products of threshing such as chopped straws and chaff could be accumulated in the stack and be saved for future use as animal feed.
Nigeria heavily relies on imported technology in areas of machinery and equipment (Bashir and dauda, 2003).
This machinery has only made a limited impact on increased food production due to several problems such as regular break down.
Experience has shown that a number of this machinery and equipment break down as early as few days after commissioning due to improper usage (yisa, 1999).
Over the years different mechanical means of shelling were imported in moderate quantities which include: power threshers of various make and models such as Nogueira, lion, midget, Alva blanch (iar, 1987).
However various tests conducted at the institute for agricultural research (iar), Ahmad Bello University, revealed various defects in the performance of these machines.
Seed losses were of unacceptable levels and cleaning efficiency was unsatisfactory.
References
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