The appropriate feed processing technology and a proper set of feed processing equipment will offer you assured feed products. Thus feed milling technology plays quite a very important role in feed production. It ensures the benign and steady development of the feed industry. Technology also provides a technique guarantee for converting animal nutrition research into high quality feed products and makes a great contribution to improving feeding efficiency and the value of feedstuffs. Feed pellets, as a kind of palatable and nutritious feed, enjoy wide popularity in feeding poultry, livestock and aquatic animals. At present, more than half of the world’s feedstuff is processed by pelleting technology.

1. Digital Re-print September | October 2013
Sieving technology in feed pellet production
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2. “ After a decade, we replaced our Tapco
Heavy-Duty buckets with the Xtreme-Duty
ones. If the new ones perform half as
well as the originals, who knows
how long they’ll last — maybe
20 years or more!
”
Jamie Mattson
Operations Manager
JAMES VALLEY GRAIN, LLC
Oakes, North Dakota, U.S.A.
Jon Hansen
Plant Operator
JAMES VALLEY
GRAIN, LLC.
Why 10 Years is Just a Drop in the Bucket When it
Comes to the Performance of Tapco Buckets
calculated that the original Tapco buckets handled 169,297,881
bushels – and most of those buckets were the originals.”
When James Valley Grain installed Tapco buckets in their new
facility in 2001, nobody expected them to last this long. A lot
of commodities of different density
variations – like wheat, corn and soybeans – have run through the original
7.05-million-bushel
terminal, which added
extra wear on the
STYLE CC-HD
(HEAVY DUTY)
buckets. Through the
®
years, the volume of
STYLE CC-XD
(XTREME DUTY) material has gone way up, too.
“Ten years is a long time for buckets to endure, especially
running as hard as we do,” Mattson says. “Honestly, when we
took them off, it was pretty incredible how well they wore. If the
new ones perform half as well as the originals, who knows how
long they’ll last – maybe 20 years or more!”
“We went from five million bushels the first year to around
30 million the last four years,” Jamie Mattson, Operations
Manager, James Valley Grain, says. “In fact, I just looked it up and
Extend the longevity of your loadout legs with Tapco buckets.
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ELEVATOR BUCKETS - ELEVATOR BOLTS
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Tel.: +1 314 739 9191 • +1 800 AT TAPCO (+1 800 288 2726) • Fax: +1 314 739 5880 • www.tapcoinc.com
*Grain Journal, Country Journal Publishing Co., Inc., Decatur, Illinois, U.S.A.
The color blue, when used in connection with elevator buckets, is a U.S. registered trademark owned by Tapco Inc. © 2013 Tapco Inc.® All rights reserved.

3. FEATURE
Sieving technology in
feed pellet
production
by Amanda Zhou,
Allance Machinery, China
T
he appropriate feed processing
technology and a proper set of feed
processing equipment will offer you
assured feed products. Thus feed milling
technology plays quite a very important
role in feed production. It ensures the
benign and steady development of the
feed industry. Technology also provides a
technique guarantee for converting animal
nutrition research into high quality feed
products and makes a great contribution to improving feeding efficiency and
the value of feedstuffs. Feed pellets, as
a kind of palatable and nutritious feed,
enjoy wide popularity in feeding poultry,
livestock and aquatic animals. At present,
more than half of the world’s feedstuff are
processed by pelleting technology.
Feed pellet processing
technology
Feed pellets have been defined as
‘agglomerated feeds formed by extruding
individual ingredients or mixtures by compacting and forcing through die openings
by any mechanical process’. Basically, the
purpose of pelletizing is to process finely
divided, sometimes dusty, unpalatable and
difficult-to-handle feed materials and, by way
of heat, moisture and pressure, into larger
particles. These larger particles are easier to
Table 1: Example particle size distribution
US sieve
12
Grams
Percentage
0.03
0.02
16
1.64
1.20
20
27.21
19.88
25
43.29
31.64
30
40.33
29.47
40
17.09
12.49
Pan
7.25
5.30
Total
136.84
100
1/8’’ grind milo based ration
28 | September - october 2013
handle, more palatable and usually nutritious
enough to ensure animal healthy growth. For
the pelletizing process technology, it has the
following steps.
Grain material selecting and
sieving
Grain materials are sieved to remove
the big and magnetic impurities. The sieving machine structure should be capable
of avoiding material blocking and ensure
a consistent smooth flow. The mass flow
concept features once the feeder opens, the
mass material will flow down without blocking, packing and will be graded automatically.
Grain grinding
Grinding or particle-size reduction is a
major step in pelleted feed manufacturing. Grain grinding generally improves feed
digestibility, acceptability, mixing properties,
pellet quality, and increases the bulk density
of some ingredients. According to research,
feed pellet quality depends on the following
factors: 40 percent diet formulation, 20 percent particle size, 20 percent conditioning,
15 percent die specifications, and 5 percent
cooling and drying.
Apart from diet formulation, particle size
is the first factor that will dictate about
20 percent of pellet quality and also
has a significant effect on the other
factors, such as decreasing the particle size of ingredients results in a
greater surface area per unit volume
for absorption of condensing steam and
increases the surface area available for
bonding. Moreover, penetration of heat
and moisture to the core of a particle
can be achieved in a shorter amount
of time with small particles and a large
surface area per unit of weight.
But this is not a one-size-fits-all situation.
The ideal finished particle size varies by the
grain being processed, and depends on the
species and life stage of the animal. Bearing
all these in mind, selecting the proper
method of grain particle size reduction is a
critical decision.
Hammer mills for grinding and
sieving
In general, both roller mills and hammer mills have been applied to the task of
particle size reduction or grinding in feed
pelletizing technology. The hammer mill has
been traditionally used to produce the finer
materials commonly used for pelleting, and
for many mash feed applications. A hammer
mill is essentially a steel box surrounding a
rotor. Swinging hammers attached to the
rotor flail out when the rotor spins. A screen
covers the discharge opening to regulate the
finished particle size.
In the hammer mill, the motor drives the
rotor to rotate at a high speed through the
belt, and on the rotor there are series of hammers. When the materials get into the working area
of hammers,
the
&feed millinG technoloGy
Grain

4. FEATURE
Table 2: Tip speed-feet/minute. Rotor diameter*RPM
Diameter
1200RPM
1800RPM
3600RPM
19’’
NA
7536
17898
22’’
NA
10362
20724
28’’
NA
13194
38’’
11938
17670
42’’
13194
19782
44’’
13823
20724
54’’
16964
"Feed pellet production
needs not only a complete
proper set of equipment but
efficient and cost-effective
processing solutions"
25434
rotating hammers with high rotation speed
strike them over and over until they are
small enough to fit through a screen. A large
amount of air also moves through the hammer mill, and it dragging any material small
enough to make it through screen holes
this becomes the final product - the larger
products are brought back to the crushing
area by the hammers for being re-crushed
until they reach the required size.
As materials move through the grinding
chamber, they tend to approach hammer
tip speed. Since reduction only occurs
when significant energy is transferred from
the hammer to the particle (large difference in velocities), less grinding takes place
when the particles approach hammer tip
speed. Many manufacturers incorporate
devices within their mills to interrupt this
product flow, allowing impact and reduction to continue. Tear circle hammer mills
have a more positive, natural redirection
of product at the inlet than ‘full circle’
design machines.
Factors determining ground
particle size: sieves
Precision and consistency of the finished
particle size have a strong effect on the
digestibility of feed pellets. A finished particle
size that is either too large or too small will
have adverse effects on quality of pellets and
animal performance.
The primary factor determining finished parti-
cle size is the measurement of the perforations in
the screen covering the discharge area. The size
of these perforations is equal to the maximum
finished particle size of the material processed.
Large particles will cause cracks and fractures in pellets. It is recommended that the
hammer mill screens for grinding do not
exceed 1/8 inch diameter. Better results can be
achieved from use of a #7 (7/64 inch) screen.
Smaller particles will increase horsepower
efficiency by increasing the throughput of
material through the die holes with less
horsepower. The finer grind also extends the
die life as it decreases the ‘grinding’ or milling
of material on the solid surface between the
holes on the die face.
The ideal particle size range of 650 to
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13210 Villarta de San Juan • Ciudad Real- Spain
T: +34 926 640 475 • F: +34 926 640 294
grain silos
&feed millinG technoloGy
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hoppered silos
Madrid Office:
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T: +34 91 726 43 04 • F: +34 91 361 15 94
September - october 2013 | 29

5. FEATURE
750 microns can easily and consistently be
achieved through proper screen selection.
In addition, screens can easily be changed
to accommodate the processing goals of a
variety of grains using the same hammer mill.
Machinery sifting is the main screen
technology applied in animal feed
machinery at present. In the present
market, punching, woven screen and bar
grizzly are widely used as screen plates.
The key part of screening equipment
which affects sieving efficiency is screen
surface.
Factors determining ground
particle size: tip speed
Tip speed, in addition to screen size, has
a significant influence on ground and sifted
particle size. High tip speeds (>18,000 Ft/
min) will always grind finer and produce more
fines than lower tip speeds. Low tip speeds
(<13,000 Ft/min), on the other hand, produce
a coarser granulation with fewer fines. As a
rule, smaller screen hole sizes should be used
with higher tip speeds, and larger screen hole
sizes with lower tip speeds. Tip speed is simply a factor of mill diameter and motor RPM
and is not easily changed on direct coupled
machines. There are a few V-belt drive hammer mills on the market today.
To produce a uniform granulation with
few fines on materials like corn, wheat, grain
sorghum, pelleted ingredients and solvent
extracted meals, an intermediate tip speed is
normally desirable. Hammer mills with a tip
speed of 13,000-18,000 Ft/Min will produce
a high quality finished product with excellent
capacity and efficiency. 38" diameter mills
with 1800 RPM motors (17,800 Ft/Min) and
44" mills with 1200 or 1500 RPM motors
(13,500 or 17,250 Ft/Min) are both used
extensively in the processing of all kinds of
feed ingredients.
For finely ground products and tough to
grind materials like soybean hulls, mill feed,
and mixtures with animal protein products,
a higher tip speed is needed because more
energy is required to grind these kinds of
materials. Normal tip speeds for fine grinding
and fibrous materials are obtained on 42" and
44 inch mills operating at 1,800 RPM (19,500
and 20,000 Ft/Min), or 28 inch mills operating
at 3,000 RPM and 54 inch mills operating at
1,500 RPM (21,000 Ft/Min). Recent developments in hammer mill grinding have included
the use of 54 inch diameter mills operating at
1,800 RPM. This very high tip speed (>25,000
Ft/Min) is particularly well suited to fine
grinding at high capacities and high efficiency.
Because a larger screen (hole) sizes can be
used while maintaining the fineness of the
grind, operating costs are reduced as well.
Mixing
conditioning. The machine consists of cylindrical dies of different diameters to pelletize
varying sizes of feed, which depends on the
age, size and spices of animals involved. Most
feeds produced are compressed pellets.
Pelleted feeds have numerous advantages
which include less feed wastage, uniform
feed intake, and destruction of growth inhibitors.
The ring die feed pellet mill is equipped
with one or more layer conditioner to be
added in the form of steam which softens
the feed and partially gelatinizes the starch
content of the ingredients, so as to process
firmer (and for aquatic feed more stable) pellets. Generally speaking, the starch
in grain materials can be ripened about
60-80% by hot air in conditioner so that
high starch or molasses content pelleted
feed can be processed.
Mixing or blending can be either a batch
process or a continuous process. Batch
mixing can be done on an open flat surface
with shovels or in containers shaped such as
cylinders, half-cylinders, cones or twin-cones
with fixed baffles or moving augers, spirals,
or paddles. Continuous mixing proportions
by weight or volume is a technique best
suited for formula feeds with few ingredients
and minimal changes. Different types of mixers, such as horizontal or vertical as well as
special mixers like liquid mixers are used to
achieve mixing.
Pellets from dry pellet machines may
exit at up to 88°C and 17-18% moisture.
The temperature must be quickly reduced
to ambient or less and the moisture level
to 10-12% or less for proper storage and
handling. Pellets must therefore be cooled
and dried. Moist pellets, if they are going
to be converted to dry pellets, also need
drying although their temperature is not
normally much elevated during manufacture.
Pelleting
Sifting
Mechanically, the pelleting process
involves forcing soft feed through holes in a
metal ring die or flat die. The holes may be
round or square, tapered or non-tapered.
This is done either by using a locally fabricated pelleting machine, which is operated by
diesel engine, electricity powered machine
or manually, or by using automatic highly
sophisticated machines with hot air or water
Pellet sifting is the last process in pellet
manufacturing and this equipment should
be located just above the bagging or final
discharge bin. A rotary sieve, as the specially
designed sieving device, is used to grade and
screen feed pellets having undergone the
secondary crushing in the large or mediumsized animal feed manufacturing plant. The
undesired feed pellets can be removed from
cooled pellets to get uniform finished
pellets. In order to get perfect product,
more and more feed pellet plants
choose proper sifters in their feed pelletizing process.
Cooling
Conclusion
Feed pellet production needs not
only a complete proper set of equipment but high efficient and costeffective processing solutions. A finer
grinded material or mixture will produce a better quality pelleted feed at
a lower cost both in terms of energy
and maintenance. The fineness of the
grind must be matched to both the
particle size and capacity requirements of the entire feed manufacturing process.
More inforMation:
Email: service@pellet-machine.net
Website: www.pellet-machine.net
30 | September - october 2013
&feed millinG technoloGy
Grain

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September - October 2013
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Sieving
technology in
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