World Grain - December 2018 - 76

FEED QUARTERLY

Ingredient preparation
Dry ingredients used in feed formulas must
be of similar particle size and distribution
by Fred Fairchild

Before being used in feed formulas, the dry ingredients need
to be of similar particle size and distribution to blend and stay
properly distributed in the formulation when mixed or further
processed such as pelleting.
Some ingredients normally are received in ready-to-use
form and particle size. This includes minerals, soybean meal,
cottonseed meal and others. Other ingredients need additional
preparation before they are ready for use. This is generally processing to obtain the necessary particle size for blending and
mixing. This may include one or more of the following processHV FUDFNLQJ JULQGLQJ VWHDP UROOLQJ RU VWHDP ÀDNLQJ ,Q WKLV
article, we will look at the equipment used for this processing.
The most used ingredients in full feed formulas are grains.
They often make up 65% to 70% of the formula. Corn is by far
used the most, but other grains such as wheat, sorghum, barley
and others are used or substituted for corn based on cost and/
or availability of the grains. These grains are purchased and
arrive in their natural kernel size and need to be ground to
smaller particles to be used in most formulas. Other ingredients such as beet pulp pellets or cottonseed pellets, which are
residues left from the extraction of oil from cottonseed and
starches from sugar production from the sugar beets, are used
and must be ground to use.
Particle size reduction is normally accomplished by grinding the whole kernels or pellets using hammermills or roller
mills. Each of these pieces of equipment has its own grinding
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ticle size produces a wide range of small to large size particles.
Roller mills grinding to the same mean particle size have a
much smaller range of particle sizes and fewer small and large
particles. All particle sizing equipment must have magnets in
the product stream before entering the sizing equipment. Foreign materials, such as stones, etc., should be screened out
beofre the product enters the sizing equipment.

mer chamber. These hammers are surrounded by a perforated
screen through which the ground product exits the grinding
chamber. A hammermill breaks up the product into smaller
particles through the impact of hammers shattering the product until the size is small enough to exit through the perforated
screen surrounding the grinding chamber. Each time a particle
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used when grinding grain or other products into a particle size
that can be combined with other ingredients and further processed into pelleted products. They also can be used to size
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ticles is not a problem. Ground particle sizes must be similar
to the particle size of other ingredients to ensure a uniform
product is added at mixing and remains that way after mixing.
The hammermill system's capacity may be increased 15%
One advantage roller mills, such as the Bühler model below, have over
hammermills is they consume less power. Photo courtesy of Bühler.

HAMMERMILLS
The hammer mill consists of hammers mounted on a spinning shaft. Whole grain or product is introduced into the ham76

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