DEVELOPMENT AND PERFORMANCE EVALUATION OF YAM FLOUR MILLING MACHINE

Abstract

Conventional method of processing yam flour is ineffective and time-consuming and this leads to low output. Automated operated yam milling machine was designed and fabricated using simulated Engineering principles from locally-sourced materials. The fabricated machine was evaluated to determine its functional efficiency. The major components of the machine include; hammer mill (enclosed with the crushers), attrition mill consisting of two cylindrical concave plates, rotating shaft, feed hopper, frame, screw conveyor, concave cylinder and discharge outlet. The machine was powered by an electric motor of 2.5 h.p. Results of the evaluation indicated that maximum milling efficiency of 86.20% was obtained at the lowest speed of 600 rpm with feed rate capacity of 73.35 kg/hr and percentage unmilled of 13.80 % was obtained at higher speed of 1050 rpm with feed rate capacity of 125.52 kg/hr, Therefore, milling efficiency was higher when the machine was operated at a lower speed. It was also observed that, at lower moisture contents of 7.5 %, milling efficiency of 82.40 % was obtained and at higher moisture contents of 18.50 %, milling efficiency obtained was 69.60 %. Therefore, milling efficiency was higher when the machine was operated at a lower moisture contents of the yam slices. The fineness modulus of the flour produced was found to be 0.31 and in line with uniformity index of 0: 1: 9 (coarse: medium: fine). With these performances, efficient milling has been achieved. Introduction of the machine in the technology will advance the production of yam flour. Therefore if the machine is made available to local users, more yam flour will be produced with less drudgery