The two main goals of vegetable processing, food safety and product quality, are sacrosanct – but the goalposts keep moving.
Each incoming truck load of carrots might vary in quality. Due to slightly different weather, soil or growing conditions, there might be more or fewer discolorations, or a sudden influx of foreign material. And because carrots are sold in varying quality grades and differing forms, product specifications often also need changing. This complicates the day-to-day business of vegetable processing, but there can be no excuses: no matter how much or how often circumstances change on the processing line, product imperfections must be detected and ejected.
During years of frontline experience working closely with processors, TOMRA Food’s sorting machines have been developed to deal with such variables. It is fair to say that today’s sorters are amazingly flexible. One reason for this is sophisticated software programs, which have pre-programable machine controls. Another reason is the wide-ranging technologies employed by sorting machines, which enable an equally wide range of specialized functionalities.
On the software side, the programs that run sorters’ automatic functions can also be manually pre-set by operators via touchscreen controls. This facility enables the machines’ detection and rejection parameters to be easily and precisely tailored to each new batch of vegetables coming down the line, minimizing downtime between batches as well as maximizing yields.
Another benefit of sophisticated software is that the machines are getting more intelligent. A good example of this is the web-based platform TOMRA Insight. This turns sorters into connected devices that generate valuable data, then processes the data into actionable information. Also, SCADA (supervisory control and data acquisition) systems can connect sorters to a control center where fault-alerts are flagged-up immediately and can be responded to remotely. These developments herald the arrival of a new era of machine networking and self-learning which will further enhance sorting efficiencies.
Then there is the hardware, the machines themselves. Developed and configured for different purposes, these can handle all manner of sorting tasks from one end of the processing line to the other. This versatility is made possible by diverse defect-detection technologies: pulsed LED light sources, high-resolution cameras, near-infrared cameras, and lasers are all deployed by today’s sorting machines, sometimes independently, sometimes in combination, depending on the designated task.
And the sorters best suited to carrots? There are three machines especially worth knowing about: the Sentinel II, the Halo, and the TOMRA 5B.
The Sentinel II is a pre-sorter which prevents defects from entering lines handling peeled carrots. This machine uses the latest illumination and detection technology, with pulsed LED sensor arrays. Adjusting these sensors with a simple user interface makes it possible to control the removal of a broad range of defects such as crop damage and discoloration and undersize product, in addition to foreign material such as stones, plastic, glass, metal, and animal matter.
The Halo is used for fresh pack carrots after the washer and polisher, and as a pre-sorter for peeled carrots to protect the peeler knives (although newer installations tend to assign to this function the TOMRA 5A). The Halo uses top and bottom sensor banks to view each individual object ‘in flight’ using a combination of LED, CCD camera and near infrared, to perform spectroscopy with 1mm precision. This advanced system views and analyses visible attributes (such as color, shape, blemish, and foreign material), as well as defects in product composition that are otherwise invisible or difficult to see.
The result is a highly accurate, flexible and controllable sort which can increase yield by up to 4% and throughput by up to 25%. Both the Sentinel II and the Halo sorter use fast and sturdy ejection fingers, ensuring effective removal of these defects.
And the state-of-the-art TOMRA 5B is used widely for processed carrots. Whether you’re sorting baby carrots, diced or sliced carrots, the TOMRA 5B sorter can be tailored to your product and more important to your requirements. The sorter can detect off-colored product or misshapen items using a specific set-up of high res cameras while ignoring any type of belt discoloration that might occur over time. The laser set-up will knock out any type of foreign matter based on structural differences with perfect ease. Struggling with very stringent customers even for slightest green discolorations? TOMRA 5B’s laser Fluo module that sorts based on the amount of chlorophyll is the perfect fit. High speed air ejectors accurately remove these defects in a smart way, increasing removal efficiency while minimizing rejection of good product.
Like a professional photographer taking pictures with intensive surround lighting and reflective underground, the TOMRA 5B inspects objects under a dome of surrounding LED light, on a reflective sorting belt. Process engineers at customers have reported that this allows them to detect very subtle color variations and very small defects, resulting in premium quality sorting.
These sorters, and others in TOMRA Food’s portfolio, enable vegetable processors to tackle varied sorting tasks by deploying varied technical solutions. Hygienic design remains paramount for the food industry and must therefore be implemented without any shortcuts. This means there’s a perfect solution available, whatever comes rolling down the line.