PERFORMANCE EVALUATION OF A BURMIL FOR PROCESSING OF MAIZE GRITS

This paper examines the performance of a burmil using dry and wet maize at variable moisture contents and operating speeds. The moisture contents of the dry maize were 10%, 12%, 14% and 16%. For wet experiment, the moisture contents were 22%, 25%, 30% and 35%. The operating speeds for both dry and wet experiments were 500, 550 and 600 rpm. The weight of samples were measured using an electronic weighing machine; the moisture content was taken with a moisture-meter and the milling time recorded using a stop watch. The results showed that milling efficiency decreased with increase in moisture at all operating speeds in the two experiments. Optimum performance was recorded at 22% moisture content for wet experiment and operating speed of 500 rpm at 74% milling efficiency. While the optimum performance for dry maize was at 10% moisture content and 550 and 600rpm operating speeds at 83% milling efficiency. The particle size distribution increased with increase in moisture content at all the operating speeds. The finest particle was observed at 10% and 22% for both dry and wet experiments respectively. A linear relationship was observed between the operating speed and the milling efficiency as well as the particle size distribution. It is concluded that a linear relationship therefore exists between the moisture content, operating speed, milling efficiency particle size distribution of maize grit. The results of the evaluation are therefore recommended for the use of farmers, fabricators and processing industries.