In 1974, Krones diversified its business by bringing both a filler and a bottle washer to market within the span of a single year. Up until then, the company had been known primarily for its labellers – as a leader in the field, with a number of patents to prove it. Come, join us on a journey into the past and find out more about the major milestones in bottle washing technology at Krones.
Krones’ first bottle washers – which hit the market in 1974 – were called Contistella and Contiranta, and they were small by today’s standards. The single-end and single-bath machines could process between 5,000 and 30,000 bottles per hour. To put that into perspective, today’s most powerful machines handle up to 135,000 bottles per hour. At the time, we only washed bottles made of glass, and that would remain the case for over 20 years.
However, it would be several years before Krones became the leader in bottle washing technology, a milestone we would reach by a real stroke of luck. It started with a technical problem that plagued nearly every bottle washer at the time: Like today, bottles passed through multiple immersion baths and spray zones for treatment with caustic and water. The challenge was that dirt particles and bits of labels would, time and again, clog the nozzles that were meant to spray the inside of the bottles. Manufacturers experimented with small rods, brushes and other options to clear the nozzles while the machine was running – but none of the solutions passed muster. There was only one method that really worked, and it was patented: a rotary jetting unit that was self-cleaning as the rotation of the tube itself caused the liquid to be sprayed through the nozzles in alternating directions.
Matthias Wahl joined the Krones Patents Department in 1986 and recalls: “Nobody could get around that patent. It was hard to sell a machine at a reasonable price without this solution. We had already done extensive research. Of course, there was no such thing as online research back then. We had to go to Munich, where we would spend hours in the search room of the Patent Office, poring in vain over old documents dating back to the German empire.”
That was the situation when Hermann Kronseder received an offer to buy the Flensburg-based bottle-washer manufacturer Zierk. It turned out that the company had a licence to this very patent. Wahl recalls the excitement: “I still remember how Mr. Kronseder came into the office holding a sheet of paper and said to Hansjörg Halbo, my boss at the time: Take a look at this! And please tell me if it will stand up to scrutiny.” And that’s how, in 1988, Krones not only gained another plant, way up in the north of Germany, but also got catapulted into the Champions League of bottle-washer manufacturers. From then on, business in this area really took off because Krones had a solution that was in high demand on the market.
The movement of the bottle-pocket rows turns a shaft in which the jetting unit is seated. As the unit rotates, the diagonally arranged nozzles spray into the bottle, first from one side, then from below and finally from the other side. When the bottle after the next bottle comes up, the spray flows through the nozzle in the opposite direction, which has the effect of backflushing the nozzle so no particles can settle and clog it.
Not long after that, in 1990, Coca-Cola in Germany launched the first returnable PET bottles. Washing these bottles was no trifling matter. If heated above 60 degrees Celsius for an extended period, the PET bottles would contract and shrink due to a “memory effect” triggered by the heat. In general, PET bottles are more susceptible than their glass counterparts to cosmetic damage during cleaning. Scuffing occurs far more readily on PET.
So Krones set about trying to determine the best way to wash returnable PET. Clearly, the hot caustic baths customarily used for cleaning glass would not work for PET. “At the time, one of our employees had the now legendary idea that we could develop an entirely different system for PET,” recalls Matthias Wahl. The result is a bottle washer that forgoes both the familiar rows of bottle pockets and the hot caustic baths. Instead, the bottles wind their way through moderately heated immersion baths and spray zones on four tracks.
The bottles traverse a considerably longer distance overall in this new machine, which means they spend more time in the caustic. This additional reaction time makes up for the lower temperature required as compared with cleaning glass and results in a thorough yet gentle cleaning of the sensitive containers. The bottles are held only by their neck rings. A locking device prevents the lightweight bottles from breaking away or falling out of the holder. The result is a virtually touchless system for guiding the bottles through the machine – a real advantage considering how easily PET bottles can be damaged when they rub or bump against other bottles or surfaces. At the infeed, they are also spaced out on four separate tracks without backup pressure and then picked up by their neck rings from above.
The new machine is called Spiragrip – and it’s a revolutionary concept that garnered much attention, as Wahl recalls: “As has often been the case in our company’s history, we caused quite a stir when we brought it to the trade fairs in 1993.” Despite the innovative approach, though, the Spiragrip never really caught on. Because another innovation did catch on – and it is more relevant today than ever before: PET recycling. Krones was also active in this area very early on, bringing PET recycling systems to market back in 2001. Today, this business area is covered by a dedicated subsidiary, Krones Recycling GmbH. The returnable PET bottle faded into the background as the lighter non-returnable variant took over the spotlight.
In the development of bottle washing technology, innovation continues to be key, often with a focus on sustainability, especially when it comes to saving water, chemicals and energy. That is why, in 2016, Krones integrated continuous caustic filtration into its bottle washers, to reduce the contaminant load and, in turn, increase the service life of the cleaning caustic. And the bottle washing technology team is already working on further advancements. So stay tuned for more!
