Reliable energy supply system for the moving pitch at the VELTINS Arena

When the whistle blows in Gelsenkirchen and football teams compete against each other, only victory or defeat counts. But here, too, nothing works without technology. The players dominate on the playing field and a maintenance-free roller energy chain under the playing field demonstrates its strength when moving the pitch.

"The world has never seen a stadium like this," enthused FIFA President Joseph Blatter about the VELTINS Arena. The European football association UEFA rated the multifunctional venue in its highest awarded category as a 'five-star stadium': "The venue more than fulfils the requirements and could even be rated as a 'six-star stadium'." One of its hallmarks is the mobile pitch. It is moved over a simple distance of 170 metres with the help of two space-saving roller energy chains and special cables from igus.

From Bruce Springsteen to the government summit

These hymns of praise emphasise the response that the arena has received since its opening in August 2001. Within a very short space of time, it has established itself as one of the most modern venues on the continent. UEFA puts the stadium in the highest classification, Category 4. To date, millions of people have attended more than just sporting events. From stock car races to music concerts and biathlons, the stadium has hosted a wide range of events.

The stadium, which was financed entirely by the private sector, impresses with its technology. The retractable pitch, the closable roof, the movable south stand and the oversized video cube under the roof are just some of the technical highlights. With the "Knappenkarte", a cashless means of payment based on chip technology was established. The admission ticket is also based on chip technology and controls access easily and securely.

Giant trough as a drawer: the retractable pitch

The playing field of the VELTINS Arena is more than just a green pitch. Embedded in a 118 metre long and 79 metre wide trough, it is the only pitch in the Bundesliga that moves back and forth over a distance of around 340 metres. It was modelled on the Gelredome in Arnhem in the Netherlands.

"The pitch is basically only inside the stadium during matches. By relocating the pitch, we ensure optimum conditions for the sensitive green surface. The stadium stands are high and generally prevent direct sunlight. This has a noticeable effect on the turf, which would otherwise have to be replaced every few months with very expensive rolled turf," explains igus CEO Michael Blaß. "And when the pitch is moved, our roller energy chains are used for the power supply. They take up very little space and have proven their strength right from the start."

The principle of the mobile pitch is relatively simple. The 11,000 tonne trough is pushed in and out of the arena like a drawer. To ensure that this works smoothly, 16 steel rails were embedded in the so-called secondary floor, the foundation. Each rail is 25cm wide and 300m long and is used to transport the trough and turfed surface into the arena.

Roller energy chains: rolling instead of gliding

The igus roller energy chain is predestined for applications in which long travel distances have to be achieved at high speeds. This is often the case, for example, with finish line cameras or in conveyor technology. The low coefficient of friction of the system can also save costs in slow applications in the crane sector or in shifting systems, as the dimensions of the drives can be significantly smaller.

At a speed of 1.5m/min. and an acceleration of 0.1m/s², two energy supply systems running in parallel are used in Gelsenkirchen for the long distances of approx. 170 metres. To ensure the adjustment mechanism, two shorter, approx. 4m long energy supply systems are also part of the overall concept.

"A key factor in this application is that the energy supply system must be weatherproof. It is essential that it works in all weathers," says Michael Blaß, putting one of the main requirements in a nutshell. "Then there is the high additional load in conjunction with the long travel. As a result of this combination, we switched from our normal chain to a roller energy chain. Here, the rollers are integrated into the side sections. As a result, the drive force required to move the energy chain can be reduced by 75%. Wear is of course significantly reduced. In addition, the rollers prevent the upper run from freezing to the lower run in winter. The chain worked perfectly right from the start under all environmental conditions!"

Cold-flexible cables for energy supply systems

But the scope of delivery was even more. "We not only supplied the energy supply systems, but also equipped them with our special chainflex cables," explains Michael Blaß. chainflex involves special cables for the energy chain system that have been thoroughly tested in our own technical centre.

All of the cold-flexible TPE control and motor cables employed can be used indoors and outdoors in a temperature range from -35°C to +100°C. "We were the first company to develop a complete energy chain system. Cables and energy chains are offered from a single source and, depending on the application, with a system guarantee," says Michael Blaß. The advantage for the customer is that the number of contact persons is reduced. And should there be any technical problems, the specialists are available at all times.