Versatile sensors multitask in German brewery

The Warsteiner Group is one of the leading private brewers in Germany, a family-run business that includes 120 companies worldwide. At the heart of the group is Warsteiner Brauerei Haus Cramer, founded in 1753 in Warstein, western Germany. Here, up to 4000 pallets are moved and 200 trucks dispatched every day.

When selecting sensors for the various inspection tasks within the busy facility, Warsteiner was attracted by the versatility of the BVS-E vision sensors from Balluff. The brewery now uses the sensors after the filling process during a 100% inspection for the presence of labels on kegs, the proper text on bottle labels as well as the quality of six-pack cluster packages.

On the bottling lines for the 0.5-litre bottles, a fast laser is used to burn in the best-before date, the time of day and the machine code on labels affixed to the rear of the bottles. The vision sensor is used to inspect these markings on each bottle with the ‘edge counting’ tool.

Andreas Zydek, managing consultant of BHV Automation, which advised the beverage producer during the design of the systems, explained: “The bottles move extremely fast. As many as 55,000 bottles pass through the system every hour. For the sensor, with its black/white CMOS image sensor (640 x 480 pixels), that leaves a processing time of 25 ms per inspection at 16 bottles/second. But the sensor handles this task with ease. We used a particularly compact VA ring light with a Fresnel lens as additional lighting. It intensifies and focuses the light power of the integrated lights.”

The sensor and light are integrated in a sealed V2A installation housing with AR-coated glass pane, which facilitates simple cleaning of the system with a large amount of water and detergents.

After filling, groups of six bottles are clustered together to form a six-pack. The cardboard packaging consists of a carton, which is automatically pushed over the bottles from above, and three cardboard tabs, which are interlocked below the bottles to form a secure package. Warsteiner uses a Balluff vision sensor here to inspect the tight fit of all interlocks on the bottom of the package. If even one of the interlocks is defective, the six-pack is rejected. The sensor is triggered by the edges of the six-packs as soon as they are detected by fibre-optic cables.

The sensor is also used in the labelling systems for 30-litre and 50-litre re-usable stainless steel kegs. It checks for the presence of labels which provide information about the beer type, filling date, best-by date, batch number and lot size. The sensor reads a 2D-Matrix code which is printed on the label, facilitating a fast detection process during the filling of 1000 kegs/h.

On the labelling line, as soon as a sensor reports the presence of a keg, a label is printed and affixed to the protective cap on the keg. Kegs that do not have a label are immediately rejected.

“We did, of course, consider other processes, such as the use of barcodes,” said Zydek. “But the high read quality is reached in this environment only with a DataMatrix code in combination with an imaging process.”

Should a barcode become damaged, soiled or swollen due to moisture, it can often barely be read, if at all. With a DataMatrix code, on the other hand, 25% or more of the information can be damaged and it is still read correctly. Compounding this problem is the fact that the position of the label on the protective cap varies slightly, so the information must be detected independent of position. For the vision sensor from Balluff with its 360° code detection, this is not a problem.