DESIGN, MANUFACTURING AND PERFORMANCE EVALUATION OF ENGINE DRIVEN BARLEY DEHULLER

Abstract

xvii DESIGN, MANUFACTURING AND PERFORMANCE EVALUATION OF ENGINE DRIVEN BARLEY DEHULLER ABSTRACT The conventional method of dehulling barley grains involves the use of milling machines or pounding in a mortar with pestles, which can be costly and time consuming. To address this issue, a batch type engine driven barley dehuller was designed and manufactured to efficiently dehull barley grains. This machine operates on the principle of abrasion to remove the hulls of the grains. Dehulling occurs through rubbing and friction generated by machine with a rotating flat iron beater inside a dehulling chamber, combined with the friction between the grains themselves as they move. The design and fabrication utilized locally sourced available materials and technology, aiming to design, manufactures, test and evaluate the performance of the barley dehuller. The study focused on the physical characteristics of barley grains and assessed how independent variables like operational speed of the beater and hopper loading affected dependent variables like dehulling efficiency, dehulling capacity, percentage of damage and cleaning efficiency. The findings revealed that increased the operational speed of beater from 900.00 to 1100.00 rpm and hopper loading from 5.00 to 11.00 kg/min significantly enhanced dehulling efficiency, achieving maximum rates of 97.22 and 98.05%, respectively. The higher centrifugal force at increased beater speed improved the separation of bran from the grains, while greater hopper loading facilitated better grain flow. The prototype dehuller demonstrated a dehulling capacity of 191.41 kg/hr. at the highest hopper loading and beater speed of 11.00 kg/min and 1100.00 rpm respectively. However, it was noted that higher beater speed led to a greater percentage of damaged grains, whereas increased hopper loadings reduced grain damage. The maximum cleaning efficiency recorded was 98.52% at 1100.00 rpm beater speed and a hopper loading of 11.00 kg/min. The dehuller was designed to handle a maximum feed rate of grains that was 0.18 kilogram per second.