Toward Pure Leaf
With its new Pure-F sorter, Koerber Technologies removes undesired materials from tobacco at the earliest possible point.
By Stefanie Rossel
It’s annoying but unavoidable: Nontobacco-related materials (NTRMs) can find their way into tobacco at any production stage, from harvesting to processing through packing, shipping, warehousing and even beyond. The range of things found in freshly harvested tobacco during the sorting process is nothing short of amazing, including civilization waste such as plastic bags or sweets wrappers, but also organic remainders such as bird feathers, insect cocoons, grass or cobwebs and even cadavers of small animals. Sand, pebbles and small rocks may also be found. This is sometimes added to by metal objects such as nuts, bolts or bearing balls from harvesting and processing machinery failure, and more frequently by packing materials such as shrink wraps, metal staples, strings or cardboard.
If not removed, the unwanted objects may have a detrimental effect on threshers and slicers. What’s worse, if not removed at a very early stage in the production process, the problem will multiply as once the NTRMs move through the thresher, they will be cut into 10 pieces or even more. The tinier the particles are, the harder and more complex it is to remove them during the following production stages, requiring, of course, even more sorting equipment.
That’s where Koerber’s new Hauni Pure-F sorter comes in: “Sorting early in the process, before threshing, can replace sorters in the downstream process,” says Ralf Kohlhardt, head of technical sales primary at Koerber. “These are the main reasons why sorting before threshing is so effective: There is a much lower amount of NTRMs. The NTRMs are bigger and hence easier to detect. In addition, it avoids that one NTRM will become 10 or more. And also hand pickers, which are standard in green-leaf threshing (GLT) processing, aren’t required anymore.”
The Hauni Pure-F, which Koerber claims is the only green leaf sorter on the market, is the successor of the Hauni Aerosort, which was already capable of processing whole leaves. Based on the proven Hauni Aerosort design, the Hauni Pure-F is sorting the leaves in an upstream flow, which is what allows it to process all kinds of whole leaves, hand-cut as well as machine-harvested. The machine features an optimized monolayer for detection because it transports the leaves pneumatically at a speed of 20 meters to 23 meters per second. “When the leaves enter the upstream airflow, they will be separated due to the air velocity,” Kohlhardt points out. “This avoids blockages and allows proper sorting.”
A heavy particle separator sorts out heavy objects such as tobacco pads or larger pieces of metal. The leaves and remaining NTRMs then travel upward in the sorter to pass the centerpiece of the Hauni Pure-F, its vision unit. The unit, featuring new processing software and hardware developed by the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB) and equipped with three state-of-the-art channel cameras, LED lights, static background and a new evaluating processor unit, detects nontobacco particles with unprecedented efficiency, the company says. In a next step, these particles are removed by air, and the NTRM-free tobacco leaves can enter the threshing process. The Hauni Pure-F sorter has been developed for strips and whole leaf in the GLT or primary and has a capacity of up to 12 tons per hour.
Opting for Camera Technology
With other suppliers such as Tomra or Key gradually withdrawing from the tobacco market, Koerber remains one of the few providers of advanced sorting equipment in this field. During the last four years, the company has continuously revised its portfolio of sorting equipment, which it now markets under the Pure brand family.
Among manufacturers of sorting equipment, the technology chosen for the actual detection process of unwanted particles has always been a bit of a holy war. The reason for this is another vital issue in the early stages of production: Certain parts of the tobacco plant itself, such as woody stalks, roots, seed capsules or moldy leaves, are just as little wanted in the final product as NTRMs, as they would negatively impact its quality. The problematic plant remainders are a category in themselves, referred to as nondesired tobacco products, and they pose a particular challenge to optical sorting systems as even perfectly good tobacco displays natural color variations even within the same leaf. Proponents of laser-based sorting systems argue that their systems also examine structural and biological differences while camera-only systems are limited to merely scanning color differences, which reportedly makes it difficult to sort out nondesired tobacco products.
Koerber has decided on purpose to use camera technology-based vision units. “Besides to the technical abilities, it is the very reliable technology which isn’t subject of any wear and tear,” says Kohlhardt. “The same applies for the LED light.”
Camera technology is also significantly less costly: Unlike laser technology, which may bring about annual maintenance costs of $30,000 during its years of operation, camera-based vision units are maintenance-free and extremely long-lasting. Koerber’s latest vision unit, benefiting from the company’s more than 20 years of experience in the field of sorting, takes these advantages even further: It is equipped with newly designed encapsulated housing inclusive of a double sealing. Integrated air-conditioning via a water-air heat exchanger makes it also suitable for warm, ambient conditions. Furthermore, it features actively cooled LED lighting. With a newly designed static background, the vision unit comes without any rotating parts, preventing the unit from scratches on the background surface and requiring no cleaning.
“What is most important about the inside of the vision unit is that it is clean, dark—i.e., there’s no reflection—and cool,” Kohlhardt explains. “Being heat [resistant] and dust resistant, the Pure design is most reliable and failure-free.”
Sixteen Million Shades
Being able to detect and process 16 million colors, the new Pure vision unit also distinguishes small color differences in the visible color range as well as in the near infrared range, which makes it possible to distinguish moldy leaves from good product, he adds. “Tobacco reflects infrared light very well. Advanced technologies and new developments contribute to the highest sorting efficiency, including much more efficient LED lighting, much higher resolution of the camera, i.e., pixel size, and a completely new and high-advanced sorting algorithm supported by Fraunhofer IOSB.”
To customers who use previous Koerber sorter models, such as the tobacco sorter Hauni TS8 or the Hauni Aerosort, Koerber offers to upgrade them with its new Pure vision unit.
Outstanding efficiency is also a key feature of Koerber’s other Pure sorter models. Its Hauni Pure 1400 T&B and 2100 T&B optical belt sorters are the only ones on the market with integrated second sorting, which means they have an in-built rerun. “Not only does this increase the sorting efficiency, but it also mainly reduces the false reject rate drastically,” Kohlhardt relates. “There isn’t almost any tobacco in the reject waste. According to the defined cross industry test (CIT) procedure, the false reject rate is reduced from approximately 2 percent without rerun to 0.2 percent with integrated rerun. Some factories have hand pickers or even a separate sorter to sort the false reject. This isn’t needed anymore with Koerber’s new technology.”
A world in which 100 percent sorting efficiency can be achieved is not completely out of reach, he says. “We are on the way. With our detection unit, we see almost all NTRMs. With CIT test results above 90 percent with the Pure, we prove that we are close already.”
