It’s all about quality and efficiency; so the better the product that is used for processing, the better the end result. And that is where sorting and electronics play such an important role. 

Electronic sorters are accomplishing a level of quality that was not dreamed of 30 years ago and optical inspection systems have become invaluable in improving quality, food safety and a maximum return on investment.

Key Technology’s Tim Reardon, says many factors are critical to the peak performance of optical inspection equipment.
These include plant environment, factory lighting, environmental factors like vibration, the compressed air supply and functional cooling systems.

“To most effectively remove defects and foreign material, the sorter’s cameras and lasers need an unobstructed view of each object, so the product must be spread with minimal overlapping to avoid hiding defects or foreign material,” said Reardon.

And, according to Herbert Engineering, the three basic functional requirements in inspection are to identify quality, remove foreign objects and perform a sizing function. 

This has been achieved with the use of new computing technology and has given operators easier management of quality control and the ability to deal with a high percentage of waste. The result is a more consistent premium final product.
Looking at methodology, Herbert says there are some benefits to the waterfall method – a high-level input feed cascading between the cameras/lasers for inspection.

These are the high capacity, relatively inexpensive manufacturing costs and simplicity of use. But there is a myth that they have a small footprint considering the product has to be raised over a metre to drop it that far so the working footprint is a lot larger than the actual machine. As a result of the speed, camera position and lack of rotation the accuracy falls short of the market leaders by quite some margin as 15-20 per cent of product is not seen. This is due to lack of rotation and product pacing, which also leads to mis-grading. 

Due to their position, the cameras get dirty and need to be regularly cleaned. The result is a higher amount of good product in the waste and less profit for the user. The system’s speed also means that the mechanics cannot keep up in high waste samples so the machine needs to be fed slower.

In linear grading, a different transport mechanism puts the product into lines so it can be inspected and graded.
Channels of potatoes on wires, track or cups are carried to multiple drops. The accuracy tends to be high due to time spent with each tuber.
However, this comes with lower capacity and a complex system of mechanisms to turn and guide the product ultimately leading to higher maintenance costs and more down time for worn parts.
The style of selection process means it has smaller drops than the cascade system and can have multiple exits. This flexibility has a cost not only in monetary terms but space in the factory. As it is accepted that electronic sorting is not 100 per cent perfect, every exit requires inspection afterwards, which negates the need for electronic sorting when you need a premium final product.
Then there’s Herbert’s Auto-sort. Herbert have worked with electronic sorters since the late eighties. They import a multi-exit linear grader the ‘Accu-vision’ from Exeter Engineering in California and co-developed the ‘Upgrader’. Having run the Upgrader for some years Herbert looked at the actual uses of the defect detection system and listened to their customers’ criticisms. They saw what methodology was available and started again with a good knowledge and a blank sheet.

The Auto-sort is based on simple roller table technology for singulation, pace and throughput combined with an intelligent chute made from rows of fingers for final direction. You get good accuracy as a result of 360 degree product viewing, product singulation and paced grading. The Auto-sort was developed to be maintenance friendly and use durable low cost parts meaning the system is robust and reliable. 

With the cameras elevated high away from the flow of product they never get dirty. This also means the drops are reduced compared to other finger bank systems that look at the product mid flight. A key advantage of the Herbert system is the fact that the fingers are in place before the product makes contact. Due to the smaller exit drops the working footprint is compact.
The cameras have an accuracy of 0.5mm2, which enables individual tuber recognition. Hence size and shape are parameters that can be set easily by the operator. There is a sampling facilty, which lets you look at the product though the Auto-sort’s eyes and it indicates graphically on the touch screen interface what the system sees as a problem. You can adjust the parameters to suit your particular customer’s requirements or load saved programmes.

At Herbert, they listen to their customers and continually develop products. Herbert is now confident with the Auto-sort and are seeing it being used in farm, fresh pack and process industries.

With foreign object removal and now texture recognition on the list Herbert see grading of brushed seed potatoes as the next big step. This will see Herbert Engineering as the force to beat in electronic sorting.

Over in the States, Key Technology’s Manta 1600, introduced last year, is doing the job perfectly too. A new family of high performance, mid-volume sorters, Manta features a 1520-mm wide scan area and up to seven cameras and two lasers and sorts as much as 15 metric tonnes of product per hour to perfectly match the requirements of most processed vegetable, potato, and fruit production lines. 

With 0.5-mm camera resolution, the Manta 1600 sets a new standard in its class and, combined with object-based sorting, performs at levels that no other sorter can match today.

Incorporating innovative design features that Key first introduced in 2008 with its two metre wide high-volume Manta 2000 sorter, the new smaller Manta 1600 was developed for the many mid-volume customers in Key’s core markets. To meet the specific needs of each application, Key can configure Manta 1600 to include a combination of cameras and lasers for on-belt and off-belt in-air viewing.

Extreme modularity allows Manta 1600 to be easily reconfigured in the field, which enables processors to confidently select a camera/laser arrangement today knowing that the sorting system can grow if their needs change. Using colour and/or Vis/IR cameras, Manta 1600 recognises each object’s size and shape as well as millions of subtle colour differences to remove defects based on user-defined reject standards.

Raptor lasers detect foreign material (FM) based on differences in the structural properties of the objects while FluoRaptor reliably detects foreign material (FM) based on differing levels of chlorophyll. Combining cameras and lasers on one platform achieves the most comprehensive sort available in the market.

With its mid-volume capacity, Manta 1600 perfectly complements the other camera/laser combination sorters from Key. While the Manta 2000 sorts up to and beyond 20 metric tonnes of product an hour and Key’s Optyx 6000 handles up to 10 metric tonnes, the 15 metric tonnes handled by Manta 1600 is ideal for a majority of processors.

Then there is Key’s Tegra in-air sorter which also processes up to 15 metric tonnes and is suitable for many applications where the shadow of the product on the belt requires full in-air sorting. Optyx 3000 is the smallest sorter offered by Key and is ideal for lower capacity requirements.

Like all of Key’s G6-enabled optical sorters, Manta 1600 can be equipped with FMAlert an enhanced quality monitoring capability that improves the tracking and control of foreign material (FM). FMAlert enables the sorter to capture and save a digital image of every object defined as FM.  Armed with these images, processors can quickly identify critical quality problems and take corrective action to maximise product quality and food safety.

The new Manta 1600 can be configured with two independently driven ejector banks to achieve three outputs. This option allows processors to produce a higher quality product without losing valuable product to the waste stream or requiring additional sorting for rework product.

With three-way sorting, processors can remove foreign material and critical defects with the first ejector bank, sending to waste, without re-sorting or losing valuable yield. Off-grade and quality defects can be ejected at the second position and re-routed for rework, while the pass stream accepts only good product that matches specifications.