Roller mills for grain and compound feed
Feed structure decides how much of it the animal will use, and structure is made in the mill. The Kahl WSB roller mill produces a coarse granulate instead of a mash-like product, with energy consumption about 50 % lower than a hammer mill.
Two fluted rolls turn in opposite directions but at different speeds. That difference is the whole trick: instead of crushing the grain, the machine cuts it. Size reduction comes from a combination of shear, cutting and pressure.
The result is a narrow particle size distribution, with considerably fewer fines than a hammer mill. This matters because dust is a nuisance later, both in pelleting and in feeding itself.
Roll speed and gap are adjusted during operation. A change of formulation does not mean stopping the line. The roll fluting is selected individually, according to the raw material.
The roll diameter determines both the material feed and the size of the grinding zone. Multi-stage grinding with screening between stages gives an even more uniform particle size.
The mills grind wheat, oats, barley, maize, peas, beans, soya, lupin and rapeseed, in animal feed lines before dosing and mixing, and as dry grinding ahead of the press in biomass pelleting.
Uniform particle size is not cosmetics but animal science: in ruminants, meal that is too fine accelerates starch degradation and leads to metabolic disorders, while in pigs a coarse structure reduces the risk of gastric ulcers at the stomach entrance, and in poultry it improves feed conversion.
For coarse meal a single pass is enough, while a narrower distribution calls for multi-stage grinding with screening between the stages.
The design is chosen according to the raw material, the required capacity and the particle size the formulation calls for.