Cost of operation, return on investment, quality design, service and high throughput are some of the main challenges and opportunities associated with potato sorting equipment. Therefore, potato processors should look at a sorting system though the filter of their specific products and production requirements. They should select a system that is tailored to what they need and which offers the versatility to be upgraded as needs change and as technology advances, to maximize the long-term return on their investment.

Potato producers and processors have always been the first in the food processing industry to show an interest towards optical sorting machines. This is explained because they can derive important benefits from a sorting equipment, mainly due to the nature of the processed product: potatoes are easily sorted (light product with dark defects) and are usually processed in large quantities 365 days a year, so that processors can take advantage of the benefits of automatic sorting, in comparison to manual selection, with a much more consistent R.O.I. than in any other segment.

Continued evolution in R&D
Manufacturers believe that optical sorters will be used even more frequently in the future, in different parts of the processing lines. Various sorting technologies will be necessary for unpeeled, peeled, chips, French fries or mashed potatoes. When the fight against contaminants is done in steps, the result is better than trying to eliminate contaminants with one optical sorter placed near the final packing, believe Raytec representatives.

“On the applications where it is necessary the detection of small defects (1 mm), Dryce could be successfully used to sort washed unpeeled potatoes, peeled potatoes and frozen diced potatoes. It rejects all contaminants such as foreign bodies, color defects and rotten products,” say Raytec representatives. “The machine is equipped with the most innovative technologies ensuring accuracy and safety: a double side view with 4 cameras, 10 frequencies pulsed LED light, high 4K resolution and a smart-jet rejection system. In addition, it has an original ultra-clean design guaranteeing high standards of hygiene. Dryce has a production capacity of up to 40 t/h,” they add.

One company that also brings innovation in their sorting machines is Herbert Engineering, which supplies handling systems for the agricultural, fresh pack, food processing, materials handling and waste management industries. Herbert is specialized in highly efficient handling systems, designed to meet operational needs and assist clients in all stages of a project implementation, from initial design and layout to building the equipment, installation and ongoing support. Their vegetable handling equipment is renowned for quality of design and manufacture. This means longer life, increased reliability, lower maintenance and lower running costs. Their Oculus sorter uses 360º vision, which allows for easy and effective inspection of every part of the tuber.

“Oculus is fitted with infrared cameras for the most effective identification of greens, and the latest digital color cameras delivering market leading resolution of up to 0.25mm sq pixel size for exceptional accuracy of defect identification,” says Mark Verschuren, managing director of the company. “Oculus identifies and sorts extremely easily and effectively for a range of surface abnormalities and diseases, including bumps and notches, skin discoloration, green and dark colors and common defects like green and mechanical damage, common scab, cracks and black dot,” he adds.

Future trends and Industry 4.0
With regards to sorting, equipment manufacturers see a clear trend towards increasing the number of sorting outlets. Having the ability to bring out special selections and to divide the bulk product into more groups, thus increasing the uniformity, raises the potential value that can be added to the raw material in the production.

“We believe that line integration in terms of higher degree of communication amongst functional nodes in a production will drive the near terms requirements for production installations,” say Newtec representatives, adding that “whether this will happen through “Industry 4.0” or some other de facto standard from IoT, the value of sharing information amongst various machine functions in a production line will be one of the key abilities, to get a fully automated and adaptive production environment.”

Newtec has been developing algorithms for analyzing and to determine the optimal way to split a given batch towards the customers’ needs and requirements. In other words, automating the process of setting up the sorting on quality and sizing, based on the given raw material versus orders to be delivered, thus optimizing the utilization of the products, to either avoid need for temporary storage, or to optimize towards best value to market. These new features remove the responsibilities expert operators have in setting up the parameters on the sorting machines, having the machine doing the parameter adjustments instead, based on large statistical insight. This way, the equipment secures a much better chance of fitting the given potato batches into product-groups based on the current business values.

Moreover, Newtec say that when choosing an optical grader, the outcome is, of course, the first thing to ensure. Can the machine do what is needed, and does it do with the accuracy needed? This goes for both size and quality. It is important to check that the machine can handle the defects which will occur for the customer, and also that the machine can be trained to grade new or unknown defects. “Secondly, it is important to check and approve the handling of the products going through the machine. For potatoes, we always minimize the drop heights in order not to bruise or damage the products. Also, we keep a constant flow of the potatoes going through the machine and avoid to take out all the energy of the travelling speed at once. Furthermore, the machine should be so good, both in the grading and in the design, that no return system is needed. This only means even more handling of the products,” the company adds.

One trend noticed by manufacturer Key Technology involves potato processors that are increasingly interested in detecting or measuring internal conditions such as sugar, moisture and oil content with a strip sorter. Improving internal defect detection and enabling accurate chemometric analysis is an area Key is working to evolve. Another direction the sorting industry is heading towards is the continued need for systems that operate autonomously and are more intuitive when human intervention is required.

“A sweeping trend in the food processing industry involves ‘big data,’ and intelligent digital sorters are perfectly positioned to deliver. Equipped with Information Analytics software, a VERYX sorter can collect, analyze and share data across the processor’s enterprise at the same time it sorts. Harvesting data about the product flowing through the sorter, whether that data is used to make sort decisions or not, enables processors to better manage raw materials and optimize processes upstream and downstream of the sorter, in addition to improving the sorter’s accept/reject decisions. By using a sorter as an intelligent data center, we’re giving our customers new ways to maximize their competitive edge,” says Marco Azzaretti, Advanced Inspection Systems Product Manager at Key Technology. “Our VERYX sorters offer our latest advancements, including auto-learning, self-adjustment algorithms, predictive diagnostics and smart alarms in addition to FMAlert and Sort-to-Grade, which enable it to adapt to normal changes in the product and environment without operator intervention. Of course, we’re continuing to develop new ways to improve automation and ease-of-use all the time,” he adds.

Continuous development
A recent area of advancement in optical sorting is the availability of optical sorting equipment for use on dirty crop. Whilst optical sorting of washed crop is an increasingly commonplace process, the removal of stones and clod from dirty crop still remains a largely manual process for most.

“As official UK distributor of the Visar Sortop Optical Sorter, which was originally designed to effectively source carrots with minimal labor requirements, we are now talking to potato growers and processors about the new Visar sorter for potatoes,” explains Edward Tong, managing director of Tong Engineering. “The new model of the Sortop has been developed to bring a fully automated optical sorter to the potato industry, which can be specified for use in both washed and unwashed conditions. Due to its intelligent software, which allows the Sortop’s software to automatically and progressively learn which faults are acceptable or not, as it works, the Visar Optical sorter for potatoes removes the need for tedious adjusting and programming that is often required with other sorting machines, and most importantly, it helps to significantly reduce labor costs whilst improving yield and reducing waste,” he adds.

Optical sorting for unwashed crop can now also be specified on selected mobile grading machines on the market. The Tong Caretaker mobile grader can be fitted with the option of an integrated optical sorter in place of a standard inspection table, for automatic separation of foreign material from crop. Using the latest camera technology, the optical sorter within the Caretaker, scans all items whilst in-flight to identify and separate crop from clod, stones and foreign objects including wood, plastic, glass, bone, rubber, metal and more. The machine offers effective separation for a wide range of potato varieties, including main, seed and processing crop.

Moreover, processing lines are getting bigger and bigger with higher levels of automation. Due to these high volumes the risk in getting FM into the final product or even the risk for very expensive product recalls is increasing dramatically. The digital sorter is capable of what no mechanic devices or expensive people on a belt are capable of. According to equipment producer Insort, an end of line digital sorter is a must have at any processing line, because food safety and quality control issues are generally getting more and more important in all food processing industries.

“Insort has recently launched its first end of line sorter Sherlock Hybrid for frozen French fries and other cut potato products. Sherlock Hybrid is equipped, as all Sherlock sorters from Insort, with Chemical Imaging Technology (CIT®), enabling classification of each object by chemical composition. This technology operates with 240 wavelengths per pixel, which allows to teach the whole range of “good products” to the machine exceeding capabilities of any other sorting equipment in the market. Any object that doesn’t fit the good product signature is automatically recognized as foreign body, which allows the highest Food Safety performance at lowest false rejects,” according to company representatives.

Last but not least, grading and inspection equipment – at point-of-origin, prior to shipment to the supermarket, or from the on-line dispatching warehouse – can ensure the produce has the desired size and ripeness without bruising or mold. In addition, sorting equipment at different stages in the supply chain will be able to provide essential information on sizing, quality and other quality markers.

“In readiness for these needs, the sorting machines made by TOMRA Group are being enabled to share data to ensure the highest standards of quality and safety. These machines are also being fine-tuned in data-gathering and application to help processors pick the correct incoming material, to get to the final product in the most efficient way,” says Bjorn Thumas, director Business Development Food at TOMRA Food.

Summing it up
In order to get the most value, a processor should consider the sorter’s capabilities as a data center as well as its sort performance. In addition to easily accessing the sets of data that most interest them, the processor should look for a sorter that easily connects with networks and other plant equipment to facilitate data sharing and integration within the enterprise.

“Finally, every processor will want to engage with a supplier that has the expertise to tailor the sorting system to meet their application’s requirements. Important non-product considerations include the level of assistance the supplier can offer during the sales process, after-sales service and support capabilities as well as the supplier’s willingness to partner in the future as application needs evolve,” Key Technology’s Marco Azzaretti concludes.