Rethinking Temperature Control

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Kathrin Eckhardt

Tel. +49-(0)351-271-808-09

kathrin.eckhardt@watttron.com

www.watttron.de