Global technology group Buhler is increasing the scope for its Z-series colour sorting system. Primarily designed to detect discoloured rice, it is now being used for a variety of other food grains.
In recent years enormous progress has been made in the field of colour sorters. It has been made possible by the electronic and the improvement of the detection systems. In rice mills, colour sorters have been applied to remove discoloured rice kernels from white rice.
"Processed by Sortex" appears on many a rice bag. In traditional rice-growing countries, this is the highest quality certificate for high-grade rice. Now this technology is also being applied to wheat, rye, and oats in combination with traditional cleaning equipment. The Z-Series colour sorters from Sortex detect ergot, dark contaminants, germ discolourations, dark pebbles, and discoloured and unripe kernels.
Quality starts with cleaning
Modern cleaning flow charts are increasingly using new-generation colour sorters because of the potential presence of health-impairing impurities such as ergot in rye. In durum wheat cleaning, colour sorters remove especially the discoloured kernels.
Semolina made from this sorted wheat has a brighter colour and fewer specks. This improves the appearance of pasta made from it. In sorting hulled oats, the dark kernels are separated from the bright ones. The bright kernels are processed into oat flakes for human consumption, and the dark ones into, for example, horse feed.
Detection of minute discolorations
The Z-Series colour sorters are capable of processing up to 14 metric tons of durum wheat an hour, depending on the machine size. Sortex colour sorters are equipped with high-performance cameras to detect minute dots or colour deviations of 0.3 millimetres and smaller.
The high-speed ejection nozzles at the machine outlet open as many as 300 times a second. Product tracking and automatic calibration produce a consistently high sorting accuracy and material throughput, Buhler claims.
Successful application in the field
Development of colour sorters started over 50 years ago. Since then, more than 20,000 machines have been shipped. Currently Sortex colour sorters are in service around the world in numerous grain mills. Their separating efficiency has been continuously improved and has reached a very high standard, which Buhler claims is due to the application of new electronics and state-of-the-art cameras.
For further information about the Sortex system or any other Buhler products please contact the sales team.
Buhler is a global Technology Group and System Partner for plant and equipment and for process expertise in the fields of Food Processing, Chemical Engineering, and Die Casting, with a worldwide payroll of about 6,300.