Abstract:
Mixture homogeneity is an issue of serious concern in the course of adding
insignificant amount of feed components in a mixture. Several different methods of
determining animal feed homogeneity are used worldwide. In the course of this work,
two feed mixers, vertical and horizontal, were evaluated for performance. Mixing
ability tests were carried out on them. The aims were to determine their optimum
performance parameters and make necessary modifications.
The coloured iron filing
method of mixer test was used. The major materials mixed include Poultry feed and
iron filings. Power supply to the mixers was from a 2hp electric motor of 1410 rpm.
While the electric motor was on, 30kg of poultry feed was introduced into the vertical
mixer immediately after which 10kg of iron filings was introduced. The mixer
operated for 20 minutes. 10 samples of the mix were taken at 2 minutes intervals. The
same process was replicated for the horizontal feed mixer. Speeds of operation were
varied by interchanging pulleys in other to determine the specific speed for optimum
mix ability. The quantity of iron filings in each sample was separated by a magnet.
The quantities retrieved in each sample were weighed. Variation in the weight
distribution of iron filings in all the samples was calculated using the Coefficient of
Variation (CV) formula, degrees of mixing (DM) and conveyance efficiency. For the
Vertical mixer, we got DM of 91.5% while it was 92.0% for the Horizontal mixer.
The Vertical mixer attained an acceptable 8.8% CV in 18 minutes of continuous
operation at 350rpm while horizontal mixer attained an acceptable 9.7% CV in 16
minutes at 560 rpm. The trough cover of the horizontal mixer was modified
incorporating a feed hopper. Dead spot was reduced within the feed trough by
blocking the space of un mixable deposit with triangular metal sheet. The mixers were also spray painted to prevent rust and for aesthetic purpose. The data generated
from this work would be of immense assistance to users and researchers of feed
mixers.
