• 9 December 2015 •

How to increase the performance of your mill by reducing the decline in grinding

In the standard conditioning process, water is absorbed by wheat through the germ opening, which is just a tiny area on the whole grain surface.
The R&D division at Omas was aiming to increase the absorbent surface by removing the waterproof layers of bran which have the highest lignin and cellulose content.

To achieve this aim, research was carried out on some prototype machines installed in three different next-generation mills in Russia, Uruguay and Italy.
 
Omas Debranners were installed where the glassiness of the wheat influenced conditioning significantly, with resulting reduction in grinding performance along the whole process.

With the new Giotto technology, the conditioning process for the wheat has been completely redesigned to have a combined scrubbing and suction action:
• Special paddles hull the outer layers of the wheat to the right level; the layers are then removed by air flow passing through the machine;
• The helical design of the paddle does not break the wheat kernels and this way, the loss of starch is comparable to that of any conventional brush;
• According to capacity requirements the machine will have a variable number of paddles, hardened to 750 HB (Brinell);
• The air flow comes from a small positive pressure fan installed at the machine inlet. Air is distributed for the whole length of the rotor, keeping a constant pressure;
• The air flow cleans the kernel and removes the scraped layers of bran, which are then collected in an intermediate receiving cyclone for inspection and control of the process. The cyclone is connected to the main extraction circuit in the cleaning section.

According to Omas company technology, different varieties of grain need different degrees of scrubbing. For this purpose GIOTTO has been developed to be easily adjustable, in a fully automatic manner, using a PLC with touch screen operator interface. The machine can be integrated and operated remotely from the mill - supervisor.

Thanks to GIOTTO, there are several benefits for mills:

1. The grain absorbs water from a larger surface, evenly and in depth;
2. water is absorbed with a 20% - 30% shorter rest time;
3. commercial yield for the mill increases by 0.5 %;
4. the milling section is supplied with a grain with ash content of less than 5-10%  and therefore, there is greater extraction of white flour;
5. TBL, mould, inorganic impurity and surface micro toxins are reduced by 70 to 95%.

Researchers at OMAS found that the conditioning water reached the depth of the kernel and that there is a lower evaporation level during grinding.

The graphs below show how the quantities of H2O absorbed by a grain sample consisting of 100 grams soaked in H20 for 3 hours is superior while the water evaporated with the passing of time is decidedly lower than of grain treated with standard processes.

From machine start-up data (19 October 2013), the check weighers have recorded a different product flow trend.

The graph below shows the variations in grinding decline on different days, showing a clearly more stable trend, due to a constant and controlled grinding decline value with different types of grain.

The loss of grinding is reduced from 3.5 to 3% when grinding vitreous grain with medium-high protein content.

The graph below shows the system performance, from which it is possible to see improvements from day 19.

The graph shows:
- increase in white flour yield by 0.81% and
- overall commercial yield increase of 1.035%.

GIOTTO has been designed for easy installation in place of any conventional grain brush, before wheat conditioning.

Further studies are ongoing as to how using GIOTTO will reduce:

• running costs for the building’s venting system;
• plansifter cleaning and maintenance;
• filter cleaning and maintenance;
• piping cleaning and maintenance.

Giotto is covered by international patent.

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