Rethinking Temperature Control
"The special thing about cera2seal's technology is that the heating elements are controlled pixel by pixel and, in combination with a fully integrated temperature control system, are brought to the point of action, achieving enormous precision in temperature control during the sealing process." Kathrin Eckhardt ©watttron
Ms Eckhardt, the use of sustainable and recyclable mono-materials for packaging is an important step towards greater sustainability for food producers. However, previous sealing systems on the market were not able to process them. What's the problem?
The systems currently available are usually permanently heated tools that seal the packaging materials together under pressure. They're equipped with a single heating cartridge and a temperature sensor. Due to their large thermal mass and inertia, they're subject to strong temperature fluctuations of up to ten degrees Celsius on the surface of the seal. This results from the localised separation of heat generation and heat dissipation.
... and that means the packaging materials are also exposed to considerable temperature fluctuations during the sealing process.
That's correct. The systems are therefore unable to process mono-materials, which have a very small processing window. Furthermore, the full-surface heat radiation of the sealing heads, including in the area of the lid, causes thermally sensitive PP material to become deformed or visually compromised. Losses are incurred due to poor sealing quality or production output, as the machine speed has to be significantly reduced.
The cera2seal SRHH sealing heads are characterised by several ceramic heating elements that provide the heat required for sealing close to the sealing surface. ©watttron
watttron now offers an alternative with the cera2seal digital heating system. How does it meet these requirements?
In contrast to current sealing systems, our heaters consist of several independently controllable heating circuits, so-called heating pixels, which enable temperature control regardless of location. The result is a stable sealing process - especially with a small processing window, as is the case with mono-materials. The heat is applied precisely and only to the effective area of the sealing surface. Recyclable mono-materials can therefore be sealed properly without compromising on quality, efficiency and productivity.
What sealing temperatures are achieved and how can precise temperature control be guaranteed?
The maximum temperature that our heaters can reach is 250 degrees Celsius.
In the cera2seal system, the heating circuits with integrated temperature sensors are positioned close to the heating surface. In addition, our heating pixels have dimensions of just a few millimetres that are adapted to the sealing task, and their temperature can be regulated individually. This means that our systems heat or seal with pinpoint accuracy and bring the heat precisely to where it's needed.
watttron received the International FoodTec Award 2024 for this development. The expert jury honoured your latest development from the sealing round heater (SRHH) product range with a gold medal. What are the special design features?
This is a sealing system specially adapted for dairy products, which has been available as a marketable solution for applications in fill-seal and form-fill-seal machines since this year. The cera2seal SRHH sealing heads are equipped with eight or 16 individually controllable heating elements. They are also characterised by several ceramic heating elements that provide the heat required for sealing very close to the sealing surface. The integrated temperature sensors, which react directly to thermal loads, keep the target value constant for perfect sealing via the control electronics. In addition, the use of our technology can reduce the energy consumption of the sealing heads by around 30 to 50 percent compared to conventional systems.
Keyword food safety: The milk processing industry in particular needs packaging concepts that offer its products special protection ...
Food safety plays an important role for both machine manufacturers and end users. Compared to the state of the art in conventional heating systems, watttron has developed an algorithm that permanently records and reads data from the heating system. Due to the heat output consumed during the sealing process, the machine operator is always able to monitor the quality of the packaging and the continuity of the process. Thanks to the digital data selection of our heaters, the consistency of the seal is also better than with conventional sealing heads. Temperature fluctuations during the production run are eliminated through control by the integrated monitoring function.
And if an error does occur in the process?
The amount of heat or energy applied during sealing can be measured for each of the heating circuits. If an error occurs, for example a slipped cup lid or product residue on the sealing surface, the sensor reports a deviation from the target value due to reduced or increased energy consumption. With appropriate evaluation algorithms, these deviations can be detected automatically and assigned to an error cause using classification procedures. With the help of this message to the machine control system, incorrectly sealed products can be specifically rejected.
Which products can the technology be used for?
There are numerous applications for sealing round heaters in the trade, for example: Yoghurt pots, coffee capsules or other dairy products in cups. Non-round formats can also be sealed using this principle. For this purpose, format-adapted sealing round heaters are modified on this technological basis.
With its digital sealing technology, watttron provides a new approach to sealing recycled lids made of mono-materials on packaged dairy products. ©watttron
What about different types of bags or stand-up pouches?
We offer our matrix sealing bars for this purpose, which are used to seal various types of bags or stand-up pouches in horizontal or vertical form-fill-seal machines. Another product range is the so-called spout & port heaters, which are used for sealing in the spouts and enable sealing-in in just one work step thanks to targeted temperature variation. In practice, they are used in stand-up pouches as refill packs with spouts for soap.
Can complicated packaging geometries also be realised?
Yes, even complicated packaging geometries can be realised with our digital heating systems. We can customise the sealing formats due to the individual heating circuits that can be arranged as required. This is the case, for example, with more complex shapes in the yoghurt pot sector, such as oval or rectangular and multi-chamber pots. On the whole, a wide range of applications is possible in various food industries.
... which special formats have already been implemented in the yoghurt pot sector, for example?
In addition to the typical round cup types, we have already realised tools for double-chamber cups or sealing heads with several nested individual heating zones for special single-serving applications. Thanks to the modular design of our heaters, even these types of special formats can be realised comparatively easily. In many cases, standard heating elements from the watttron portfolio can be used to realise a customised solution in a short time.
If producers want to customise their packaging materials, there's no way around conversions. Can existing machines be retrofitted with the new system?
We hear this question very often from our customers and the answer is a clear "Yes!". This is another economic advantage of our technology, as most of the systems in our product range can be used as retrofit solutions. If the customer wants to switch to the watttron system, it doesn't have to invest in a completely new machine, but can simply replace the heating system. An increasing number of OEMs, such as IMA and Waldner, also offer this step directly to their customers. We also have simple solutions for integration into the control system - from stand-alone HMI systems to full integration into the existing machine control system.