Evaluating the Effects of Milling Speed and Screen Size on Power Consumed During Milling Operation

This study was conducted to evaluate the effect of rotor speed and screen size on power consumed during milling operation. The milling system was tested using three fish feed ingredients; bone meal, groundnut cake and maize. The moisture contents of the ingredients bought from the market are 13.1%, 14.7% and 17.5% dry basis, respectively. The milling machine was evaluated with the 3 kg of each feed ingredient and was replicated three times for each of the experimental parameters. The machine parameters varied during the experiment includes four screen sizes (1.5 mm, 2.0 mm, 2.5 mm and 3.0 mm) and five rotor speeds (1500 rpm, 1800 rpm, 2100 rpm, 2400 rpm and 2700 rpm). Regression analysis was carried out on the data collated. The analysis was used to develop a model which is capable of predicting the electrical energy (kJ) consumed. There was no significant effect of screen size on the average power consumed during milling since there is no linear relationship between power consumed and screen size. However, there is a significant effect of speed on average power consumed, the power consumed increases as speed decreases therefore making milling operation at higher speed to be cost effective since it doesn’t require much power to achieve the required output. The P-Value depicts that screen size has no significant effect on the electrical energy consumed during the milling operation while speed has a significant effect on the electrical energy used at 95% confidence level.