Sorting It All Out

Efficient and reliable removal of NRTM and NDTP from tobacco at the threshing and primary stages is a crucial task that not only ensures final product quality but also helps prevent potential equipment damage. Tobacco Asia explores the specialized sorting machinery offered by the two world leaders, Hauni and TOMRA.

By Thomas Schmid

Foreign objects can find their way into tobacco at any production stage, from harvesting to curing; to packing, shipping, and warehousing, and beyond. Referred to as non-tobacco related materials (NTRM), they are strictly speaking any materials or substances that are, well, not tobacco. Another category in itself are actual parts of the tobacco plant proper, such as woody stalks, roots, seed capsules, or such plant parts which are not wanted in the final product because they’d negatively impact its quality and purity.

NTRM: a plethora of non-tobacco stuff

Tobacco can get contaminated with NTRM at pretty much any stage during production and processing. While the bulk of NTRM are introduced coincidentally or accidentally, it sometimes can be the result of carelessness during farming, harvesting, and processing. Bird feathers, animal droppings, insect cocoons and pupae, cobwebs, grass, and weeds can find their way into tobacco bales. Sand may be left clinging to leaves, but pebbles and small rocks also may be contained in bales and pressed strips.

ALSO: The Wall of Shame

Civilization trash like discarded plastic bags, candy wrappers, and the like also is relatively common. Harvesting and processing machinery failures may unduly “enrich” tobacco with nuts, bolts, bearing balls, and other metal objects; and the consequences for threshers or slicers can obviously be disastrous if they are not removed. Packing materials such as metal staples, strings, cardboard, shrink wrap, or wood chips from palettes and crates are yet more examples for NTRM. Even cadavers of small animals like rats, field mice, or reptiles are frequently discovered during sorting. Finally, some of the tobacco itself may be tainted with molds, rotting leaves, and similar. Many processing plants maintain their own “wall of shame” (see side box) displaying sometimes mind-boggling objects.

NDTP: tobacco that is Not Needed

While the term NTRM strictly is used for any material or object that explicitly is not tobacco, sorting also concerns a second category referred to as “non-desired tobacco products”, or NDTP, according to Lars Janssens, global market manager tobacco at leading tobacco sorter supplier, TOMRA. “The term describes typical product defects resulting from an increased level of mechanization in the farming and harvesting process such as woody stalks, torn-out roots, and seed capsules.”

Leaves and stems themselves also can sustain defects during curing, fermentation, storage and shipping. “Moldy tobacco can therefore also be considered an NDTP,” said Janssens, just like bruised, squashed, water-logged, or heavily discolored leaves. Some of these may be deliberately introduced to otherwise perfectly good product by dishonest farmers or traders (for more on this see our side box). “Luckily, the industry has slowly gotten around to devise measures that ensure it is paying for tobacco instead of rubbish,” Janssens remarked. This may be so, but the bottom line is: Whether NTRM or NDTP, they both need to be reliably removed before tobacco can be processed further.

Sophisticated NTRM/NDTP Detection

A powerful arrangement of permanent magnets or electromagnetic coils installed at feeders, blenders, or conveyor belts usually is effective enough for removing larger metal objects. And so-called “heavies” (pebbles, clumps of dirt, etc.) can be separated by running the tobacco over a series of simple shaker sieves or impact screens of various mesh sizes. But, small metal pieces (e.g. staples) or tiny heavies can still easily escape these mechanical sorting methods and more sophisticated tools are needed to discover and eject them together with the myriad of other NTRM and NDTP that may be present.

“The most effective NTRM detection method is by way of an optical system,” explained Janssens. It scans run-through product for foreign objects and potentially existing tobacco defects. The tricky part is of course that even perfectly good tobacco displays natural color variations even within the same leaf. “Therefore [TOMRA’s] sorting systems do not limit themselves to merely scanning color differences as a camera-only system would do. Instead, our sorters also examine structural and biological differences through integrated lasers,” “In simple terms, the laser light penetrates the materials, determining their structural properties and – more importantly – biological or chemical differences. For example, actual tobacco contains chlorophyll, and that sets it apart from most NTRM, which do not contain chlorophyll.” Once identified, the unwanted material is then accurately removed by triggering compressed air valves.

Ruling the Sorter Market: Hauni and TOMRA

Hauni Maschinenbau GmbH and its various subsidiaries have been renowned throughout the industry for several decades as suppliers of a tremendously comprehensive catalogue of machinery and equipment. From cutters to filter and cigarette makers, from packing machines to lab equipment and more, the group of companies is sort of a one-stop center when tobacco manufacturers are looking for solutions. And, of course, Hauni also offers a wide range of sorters that can be deployed in both the GLT and primary industries to remove any NTRM imaginable, as well as NDTP.

Meanwhile, Norwegian firm TOMRA was founded in 1972, but initially focused on food processing equipment and a variety of non-tobacco related business sectors such as mining and recycling, industries in which the company fostered its ability to sort a range of over 180 different kinds of products, ultimately making it into the largest sorting company in the world. Its vast expertise in a diverse range of sorting technologies (camera, laser, x-ray, EM sensors, etc.) allowed it to combine them into so-called hybrid machines capable of delivering optimal sorting efficiency in any targeted application area. TOMRA eventually also ventured into the tobacco industry when it acquired Belgian Electronic Sorting Technologies (BEST) in 2012. At that time, BEST already had an excellent reputation as a world leader in tobacco sorting. Like Hauni, TOMRA currently likewise maintains an impressive tobacco sorter portfolio that addresses all and any sorting needs, from farmer to finished product.

The Hauni universe of sorters

“From processing tobacco all the way through to manufacturing the finished cigarette, accurate removal of NTRM is essential for product quality,’ explained Frank Schuster, project manager process design sorting equipment at Hauni Maschinenbau GmbH. “It keeps customers happy, ensures smooth production sequences, and helps avoid unnecessary material costs.” To handle the sheer variety of NTRM that can be present, Hauni markets a comprehensive range of sorting machinery, which according to Schuster “covers the entire spectrum of NTRM solutions for GLT and primary sectors.”

Hauni XC

A relatively simple mechanical unit, the XC has been particularly designed for the removal of strings and other long fibrous materials. Tobacco is conveyed over rotating cleaning rollers on which fibrous NTRM are caught and retained. There are virtually no tobacco losses and Schuster called the XC “an ideal addition for optimizing NTRM separation efficiency.”

Hauni Aerosort

This high-capacity pneumatic sorter integrates two distinct heavy-particle removal and optical sorting functions. Used for all types of tobacco in the GLT and primary sectors, it boasts a sorting efficiency of more than 85% in cross-industry tests (CITs) and processes tobacco at a rate of 3 to 12 metric tons per hour.

Hauni Tobaccosorter 8

According to Schuster Hauni’s “cutting-edge belt sorter,” Tobaccosorter 8 is suitable for all types of tobacco in GLT and primary processing. It optically inspects tobacco at a mass flow of 3 to 10 metric tons per hour and has shown a sorting efficiency of over 87%, including integrated second sorting run in CITs (single sorting run above 93%). If more mass flow should be needed, it’s possible to run several of the sorters in parallel. By arranging a second post-sorting path the ejected material can be subjected to another sorting so that tobacco loss can be minimized ten-fold. This is only possible thanks to the high pixel resolution of Tobaccosorter 8’s cameras and could not be achieved with a laser system, Hauni claims.

Hauni Optyx

The company’s most compact belt sorter, Optyx is designed for processing stems, tips and ripper shorts in the GLT and primary sectors. It is often deployed by customers with high expectations concerning the good product ejection rate, which is ten times less with Optyx than with comparable equipment. Optyx is also used as a second pass unit, for example in conjunction with Tobaccosorter 8. Optyx achieves a sorting efficiency of more than 95% at a put-through of 0.75 to 5.5 metric tons every hour.

All Hauni sorting solutions – including separators, permanent magnets, and metal detectors - have consistently delivered outstanding results in a variety of applications and settings and fared exceptionally well in tests.

“Especially our superior high-end camera technology-based units show a sorting efficiency second to none,” said Schuster. “Camera technology is preferred in cases where the color differences between natural NTRM and tobacco are less pronounced, for instance such as in the Indonesian hand-cut tobacco market, which we have furnished with our machines. The high color resolution of cameras gives a significant advantage. A false ejection rate of less than 2% in the first run is achieved in all kinds of sorting applications, like CIT or natural NTRM. In a second run, the so-called re-run, the overall ejection rate is even less than 0.2 %.”

Hauni’s high-precision machines are appreciated by customers on all continents and who comprise some of the best-known names in the industry. “We don’t have clearly defined key markets, which is of course because we sell our sorters to all regions, and where Hauni sorters have been placed in primaries as well as in GLT facilities. In Asia, we are currently represented in countries such as China, Indonesia, India, Taiwan, Thailand, Bangladesh, Hong Kong, and Japan,” concluded Schuster.

TOMRA sorters: in high demand around the world

Claiming that its global market share for tobacco sorters could “easily be between 60 and 70%,” TOMRA said its current key customers come from the PMD, SMD, and GLT sectors from all over the world. “But our install base in Asia is particularly huge and probably the biggest of all our other territories - at least for now, because we also see stable growth in other territories,” said the company’s Lars Janssens. He added the main demand drivers for TOMRA sorters in the region are countries like China, India, Japan, and Indonesia. And with an extremely well-developed sorting machine portfolio at its hands, TOMRA certainly is a force to be reckoned with.

TOMRA Cerberus

At the core of the Cerberus is a roller deck designed to create a single layer of product (Janssens: “After all, you cannot sort what you cannot see.”) and it is therefore ideal as an in-feed system to the actual optical sorters.

Cerberus then separates small-size tobacco particles (which typically are highly contaminated with NTRM) and bigger-size tobacco particles (typically less contaminated), because sorting uniform fraction sizes separately increases the sorter’s performance. Secondly, Cerberus’ modular design allows to add a Velcro system to catch strings, as well as an electromagnetic sensor for removing metal objects. “With its sensor and pneumatic removal system, Cerberus can accurately eject even smaller items and drastically reduce the amount of good tobacco that is removed along with defects when compared with a traditional magnet with drop flap system,” said Janssens. He added that “the combination of Velcro, roller deck, and EM detection provides a footprint reduction of close to 80% compared to individual components.”

TOMRA Helius

The company’s best-selling Helius range comes in sizes of 640mm, 1,200mm, 1,600mm, and 2,400mm to accommodate different flow rates as needed. It can be configured to either process stems or lamina strips/whole leaf. “The technology is the same for both applications. Only the in-feed is different, as less effort is needed to spread stems as opposed to strips when creating the product mono-layer in the scanning zone,” Janssens explained. Helius subjects product to a free fall of 3 meters per second past its optical system, ensuring it is spread naturally when released from the in-feed shaker. Meanwhile, TOMRA’s largest Helius unit with a width of 2,400mm is basically “a double Helius 1200 set-up,” according to Janssens.

“We place two Helius 1200 sorters together that will work as one single system.” The reason for not designing an actual 2,400mm wide Helius is two-fold: Firstly, the laser light would need to travel too far, losing intensity and thus bringing about decreased sorting efficacy. Secondly, it’s simply a matter of such a gigantic unit not fitting into a standard shipping container, which affects transportation cost and causes handling issues.

TOMRA Stratus

“While the Helius allows for highly effective end-of-line sorting at GLT level, it does not need much explanation that the threshing process itself is a negative contributor to the performance of end-of-line sorters, because one single big defect before threshing ends up in a few hundred smaller particles after threshing,” said Janssens. And the smaller the particles, the exponentially more difficult they are to remove without dramatically affecting the good tobacco ejection rate.

This is where Stratus comes in, a unit specifically designed for sorting whole leaf before threshing. “Stratus deploys an air lift system, which separates heavy items like metal, stones, tobacco pads, or bundles and stalks before the leaves then pass an optical system in a laminar stable airflow of around 20 meters per second.”

TOMRA TB5

A belt-based unit, TB5 can be used on stems, strips as well as cased whole leaf of up to one meter across. Due to the high speed of 5.5 meters per second with which product passes before the optical system, TB5 can handle a flow rate of up to 10 metric tons per hour in the case of strips, a little less for whole leaf.

TOMRA Opus

This model was the first sorter in the entire tobacco industry that combined two different sensor technologies: camera and laser. Like Helius, Opus is spreading product in free fall. However, its typical application is not in primary processing but rather at the end of the threshing line, sorting threshed stems. As opposed to manual harvesting, mechanical harvesting can cause tobacco plant stalks and roots to mix in with actual leaves. “Opus allows us to sort stems from stalks, roots, stones and any other typical kind of NTRM that we encounter at this production step,” said Janssens.

All TOMRA tobacco sorters are currently laser-based, as internal trials as well as field results have shown that this technology outperforms existing camera solutions, according to Janssens.