Bühler’s new Vertical Pearler Osiris MTPA. Photo courtesy of Bühler.
UZWIL, SWITZERLAND — Bühler has introduced the Vertical Pearler Osiris MTPA to be used for pearling the outermost hull layers from various types of grain.


The innovative and sturdy design, revised drive concept and diamond abrasion medium result in more efficient pearling compared to other machines to date, Bühler said.

The additional processing step produces more pure and almost speck-free semolina. Semolina quality is improved and the lower portion of hulls means higher yield with a constant ash content, the company said. Compared to mills without pearlers, a larger amount of pure semolina is produced. The pearling process also is used to process end products such as barley and sorghum.

Conventional grain pearling machines usually use abrasion stones as grinders, which wear and can break off. The new Vertical Pearler Osiris MTPA uses synthetically produced diamonds as a grinding medium, as diamond is known to be the hardest abrasive.

The newly developed grinding wheels on the Osiris MTPA are steel that has been coated with diamond grains through a galvanizing process. This construction is resistant to higher pressures and guarantees lifetime constant outer diameter. The coating also makes it possible to optimize the circumferential speed, which increases the pearling effect.

The diamond coated rotor is directly driven by the main motor. Direct drive means that the costs and maintenance associated with drive belts are eliminated, Bühler said. Plus, there is one less source of possible contamination.

The new type of construction and new abrasion medium can save up to 20% in energy costs compared to other grain pearlers with the same throughput and pearling performance, the company said.

A new aspiration system creates even aspiration across the complete height of the rotor. Fresh air is drawn in directly through the grinding rotor creating optimal removal of the grinding flour.

The new pearler can achieve an index performance of 8 tons per hour at an 8% pearling degree when processing durum wheat, Bühler said.

The housing is casted and the wear parts are easily accessible by opening the aspiration channel flap. The machine is automatically controlled and can be operated directly or from the command room.