Qipack, the founder of the infrared leak-detection system called QipCam, developed new techniques to detect leaking sachets. Instead of measuring the heat of the seal, the patented QipScan measures the movement in distance of the sealing bars. A derogation in the closing movement of the sealing bars often means defectively sealed packaging and the possibility of leakage.

The sealing bars of the flowpack machines continuously make the same movement to seal packages by using heat. However, Qipack discovered that not every movement is similar. Waste between the sealing bars, creased foil or product can become stuck and cause derogations in the sealing-movement. This causes the sealing bars to not close properly, resulting in the possibility of leaking sachets. Moreover, heat transfer of the sealing bars has consequences for the movement it makes: it is too hot or cold and dirt deposits may occur on the sealing bars. The QipScan will reportedly notice every difference in the sealing bars’ movements.

Reference Profile                                                                                                                                         To measure the distance, Qipack has installed two sensors on the sealing bars. These highly sensitive sensors measure the last 500 micrometer of the sealing bars’ closing movements. The detection process starts with the programming of the closing process. For each foil and machine, the QipScan software creates a diagram with a reference profile of the sealing process with the distance plotted over time. With clean bars and the optimal sealing temperature, the software creates a profile of the sealing movement of the sealing bars. “A 140 micron PE film gives a very different profile than a thin PP film of 30 microns,” says Alexander van Puijenbroek, owner of Qipack. “Per line, foil and product combination, we create a profile. Qipack’s QipScan leakage detection measures the distance movement of the sealing bars by using sensors.”

Closing Process                                                                                                                                              The closing process starts with colliding the sealing bars that cause a dip in the diagram. The knife that cuts the foil causes a series of waves, followed by heating of the foil. The line in the diagram gradually drops to the moment of sealing. The sealing shows another dip in the diagram to indicate that the foil has melted and the packaging is closed. The seal bars will re-separate and the next closing movement is recorded. The QipScan software calculates a maximum and minimum — derogations may not cross these. Any measurement outside these limits indicates a disruption of the closing process and a leaking packaging.

Affordable Alternative                                                                                                                                  Qipack won the Dutch Packaging Award in the engineering category in 2017. “Our infrared system is more accurate, but also more expensive,” says van Puijenbroek. “This allows us to see where the seal is located, how much pollution there is and to check the pressure and seal temperature. But, if you use a standard infrared camera, we need a measurement time of 50 milliseconds. This time is too long for sachets that fall, like vertical vvs machines. The fall movement in such a flowpacker is too fast to be able to measure properly. That is solved with high-speed cameras, but they are very expensive, at least €50,000. That's why we have the QipScan.”

For more information visit www.qipack.com.