To prevent long queues at busy bars, One Two Beer GmbH has developed an automatic beer dispensing system. The centre piece is a mobile dispensing head that inserts into the bottom of cups and enables refilling in five seconds without over-foaming – built with a lubrication-free, hygienic and durable dryspin drive spindle from igus.
It’s festival season and the sun is shining, your favourite band is playing, the atmosphere is brilliant – all you need is a cold beer. But the queues at the beer tent are so long that you miss three songs. But One Two Beer GmbH from Vienna are determined to spare festival-goers this frustration, and has developed an automatic, fast beer dispensing system. Two plastic cups are placed side by side, like a coffee machine, push the button and two dispensing heads move to the bottom of the cups. The beer flows fast and, by filling from the cup base, there is no over-foaming. The beer is tapped in just five seconds, and you are back at the concert in no time.
Lubrication required
While the beer “robot” may seem simple and elegant, its manufacture was a design challenge. "In order to enable a pour within seconds, a fast and low-friction linear guide was essential," says Tamás Kozma, Chief Information Officer at One Two Beer GmbH. The system should deploy to a tenth of a millimetre, and also be as compact as possible to enable efficient transport. It should also be insensitive to the harsh festival environment – including dust, high temperatures and condensation. "Since our machine works in the food sector, a 100 per cent lubrication-free application with FDA compliance was also crucial for us,” Tamás adds. After a lengthy search, the company’s engineers finally found a suitable system at igus: a complete linear guide unit consisting of a compact lead screw and nut from the dryspin series as well as a suitable stepper motor.
High-performance plastic and stainless steel allow hygienic and trouble-free dry running
The linear guide works like this: The tap is mounted on a flange threaded nut from the dryspin drive spindle series. When the NEMA-23 spindle stepper motor rotates the spindle, the tap moves up or down – a simple system. But there are some special features: The threaded nut is made of an FDA-compliant high-performance plastic, a material with self-lubrication that allows for low-friction, dry running (FDA = US Food & Drug Administration). Unlike lubricated metal variants, the polymer nut does not run the risk of becoming a dirt magnet from the lubricating grease. It is easy to clean, with water or high-pressure air. The linear guide is both hygienically and mechanically sound. Due to the pairing of plastic and stainless steel, there is no corrosion. And thanks to eliminating relubrication work, maintenance is unnecessary.
Threaded spindle achieves 82% efficiency
However, it is not only corrosion resistance and insensitivity to dirt that gives the linear guide a long service life, the geometry of the dryspin technology also enables high performance. “Thanks to this asymmetry, we have managed to extend the guide’s service life by around 30% compared to symmetrical trapezoidal threads,” says Rob Dumayne, drytech director at igus UK. “In addition, the flank angles of the threaded nut and spindle are flattened, so we can achieve an above-average efficiency of 82 per cent."
