World Grain - December 2010 - 70

TECHNICAL PROFILE: POULTRY FEED PRODUCTION

good condition. Exactly the same is true for a feed production
plant. What is required is the correct process, the right equipment, properly trained personnel, and a carefully maintained
and intact plant. These requirements are essential in order to
master the challenges of the future.

FROM HAMMERMILLS TO ROLLER MILLS
From the list of possible improvements, let's focus on the
grinding process. A lot has changed over the past 10 years,
especially in this area. Indeed, you might even almost say:
from the conventional hammermill via the vertical hammermill to the roller mill.
That's not to say the roller mill is a new technology. But
using rolls for size reduction is undergoing something of a
renaissance in feed production plants. This is because of the
following benefits:
* low specific energy consumption;
* high particle size flexibility through automatic roll gap adjustment and the use of double or even triple roller mills;
* compact design including bypass system;
* low maintenance requirements;
* production of a good feed texture, with hardly any fines
thanks to narrower particle size distribution than that achieved
by hammer mill grinding;
* lower moisture loss than by hammer mill grinding; and
* suitable for both pre-grinding and post-grinding
applications.
Today, either double or triple roller mills are used, depending on the required processing capacity and the grinding method (pre-grinding or post-grinding). In a triple roller
mill, the sole function of the first roll pair is to reduce large
particles such as sugar beet slices or soy extraction meal.
The second and third roll pairs then produce the desired
product texture.

GOALS DETERMINE THE CONCEPT
What are the requirements that must be satisfied to achieve
the defined quality targets? First of all, a business idea is needed on which to base one's goals. The goals pursued by individual feed producers may vary widely. Some aim at achieving price leadership, others at producing niche products, and
yet others at manufacturing premium segment feeds, and so
on. Another option is to target a specialized feed market.
Let's assume that your customer operates a feed manufacturing plant which produces a high proportion of poultry
feeds. Let's further assume that this market is to remain the
strongest pillar in the company's strategy for the future and is
therefore to be expanded.
These targets give rise to the following questions:
* Does the feed texture meet the needs of the market, or
can you further improve it in the interest of your customers?
* What can you do to improve the feed conversion rate
by the animal?
* Does your poultry feed satisfy the increasingly stringent
sanitation requirements of the market and consequently of the
trade chains?
* If your plant produces different feeds, has it been designed to allow a clear separation of the individual production
lines, including the loadout section?

CORRUGATIONS AND CONDITION OF THE ROLLS
The product texture is greatly determined by the roll corrugations (fluting). What's important is not only the configuration and geometry, but also the condition of the individual
corrugations. Differences undoubtedly exist depending on
whether operation is based on "sharp to sharp," "with or without spiral," or some entirely different combination. This may
lead to discussions similar to those that you know today from
the determination of roller shells of pellet mills. Here, too, the
discussion continues unabated as to whether it is preferable to
use dimpled or corrugated (fluted) rolls. It is therefore understandable that many production managers rely on their own
experience when making related decisions.
What is more important than the selection of the "right"
corrugations is their condition. The better the condition
of the flutes, the better also the particle size distribution,
and therefore the lower the content of fines of the feed. A
well-maintained roller mill will allow up to 40,000 tonnes
of material to be ground before its rolls need to be recorrugated (refluted) or - after two or three refluting cycles
- exchanged. Of course, this also greatly depends on the
raw materials that are ground. Different raw materials and
the pre-cleaning process applied may have a major impact
on the wear to which the corrugations are exposed - both in

Buhler's pellet mill with hygienizer. Photo courtesy of Buhler.

December 2010 / World Grain / www.World-Grain.com

http://www.World-Grain.com

World Grain - December 2010

Table of Contents for the Digital Edition of World Grain - December 2010