Improving illumination in sorter cuts waste and raises quality

An Austrian food processor has improved profits, driven up product quality and cut waste by simply upgrading the lights in its Bühler SORTEX optical sorter from fluorescent to LED.

An Austrian manufacturer of bakery products is one of the first European companies to increase productivity and reduce waste by switching to LED lighting in their Bühler SORTEX optical sorter. The decision by the food producer Arnreiter Mühle to replace the more traditional fluorescent lights used in sorters, is set to become an industry trend as companies look to benefit from the lower running costs and the consistent illumination provided by LED lighting.
During the sorting of raw materials such as soya, wheat, malt, spelt, rye, barley and oats, the Bühler SORTEX optical sorter is looking for the subtlest difference in color to ensure it only rejects unwanted materials. Key to this process is the level of illumination of the raw material during the sorting process, to enable Bühler’s high-resolution optic sensors to operate at optimum efficiency.
While a relatively simple upgrade, the result of switching to LED three months ago is already paying dividends for the company. “Since using the LED lights we have found that once the calibration is properly set, we don’t waste so much of the raw materials thanks to less of the good material being rejected,” said CEO Walter Arnreiter. “We could see the quality of the end product had improved with the upgrade. For us, it means less waste, higher profitability and greater product security.”
The industry shift to LED lighting is part of a wider move away from halogen and fluorescent bulbs, both in the manufacturing and domestic markets. LED is not only longer lasting, it is cheaper to run, saving you up to 60 percent in energy costs. Additionally it performs consistently and offers a more directional light than fluorescent bulbs, making it ideal for projecting light onto the viewing area of an optical sorter.


Based in upper Austria, about 40 kms from the regional capital Linz, Mr Arnreiter’s mill produces specialized ingredients for bakeries and food processors, as well as biscuits and muesli. The company sorts and processes a range of raw materials including different types of wheat, soya, spelt, barley, oats and poppy seeds. Mr Arnreiter points out there is already a market awareness of the quality benefits provided by LED lights. He said: “When I talk to our customers in the cereal industry, they have experience with these machines and customers are already aware of the advantages of the upgrade.”
LED lights are also safer to handle during maintenance with no chance of them accidently shattering. Installation time is scheduled for half a day and can take place during the annual maintenance service to reduce any potential production down time. Customers switching to LED lights also benefit from not having to pay for new fluorescent tubes every year as they degrade. LED lights operate at peak performance for five years ensuring the sorters do not require recalibration as the lights deteriorate. Fluorescent tubing may also create an inconsistent illumination along the length of the tube resulting in variable sorting performance. “When using the fluorescent system the brightness can decrease over time and the Bühler SORTEX technicians told me that the light may not be consistent with the left and right sides not being as bright as in the middle,” said Mr Arnreiter.


The LED upgrade is available for the A, B and Z range of Bühler SORTEX optical sorters. Fluorescent lighting is seen as an aging technology, with the chance that replacement parts will eventually become more difficult to source. All new Bühler SORTEX optical sorters come with LED lights already fitted.

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