PERFORMANCE OF GRAIN GRINDING MACHINES IN TAMALE METROPOLIS

Abstract

This study was conducted in the Tamale metropolis in the Northern Region of Ghana. The study aimed at evaluating the performance of grain grinding machines in the metropolis. The treatments used were grain condition (moist at a moisture content of 10-18.22 % wb and dry) and burr mills of the same type (A, B, C, D and E). The treatments were replicated three times (5 mills x 2 treatments x 3 replications =30). Fifteen corn samples which were to be ground moist were soaked in water for 48 hours. The other fifteen samples were ground in the dry condition. Five mills were selected from a total population of twenty five mills from the metropolis. In this study, the influence of moisture content and other grinding characteristics on milling performance were studied. The attrition mills were evaluated for their fineness modulus, uniformity index, milling efficiencies, average particle size, milling losses of flour, flour temperature and electrical power requirement during milling. The fineness modulus was high in dry grains milling than moist grains milling. Aggregate of flour fineness was largely associated with moist grains milling than dry grains milling. Average particle size was high among dry grains milling and low in moist grains milling. The milling efficiencies ranged from 54.33 – 63.33 % for dry grains and 63.33 – 75.65 % on moist grains milling. Flour losses were high among moist milling and ranged from 9.04 – 16.20 % and 7.60 – 15.10 % on dry grains milling. Flour temperature increased among dry milling than moist milling ranging from 62.09 - 67.15 oC and 54.17 – 58.20 oC respectively. Results of the study have shown that grinding of dry grains to any acceptable fineness as moist grains would requires more energy demand and therefore extra cost of grinding. The study recommends periodic training of grinding mill operators to study performance characteristics of grain grinding.