Media-resistant plain and spherical bearings in the solar cleaning robot

Cleaning at lofty heights - TG hyLIFT GmbH from Gronau has set itself this task. The company has developed the "hyCLEANER black SOLAR" cleaning robot to remove dirt from solar installations. The engineers rely on lightweight, lubricant-free and maintenance-free plastic plain and spherical plain bearings from igus® for the wheels and brush bearings.

Solar and photovoltaic systems provide clean energy generation worldwide. In order for these systems to work efficiently, the solar surfaces must be clean. Particularly in areas where agriculture is practised, they are regularly exposed to pollution from environmental influences during harvesting and ammonia vapours from livestock farming, which reduce the economic efficiency of the surfaces. However, the performance of solar systems operated by private companies is also affected by fine dust and pollen in cities, which cannot be removed by raining. Even localised soiling of individual cells caused by bird droppings or lichen can reduce the efficiency of the entire system due to the series connection, as the weakest module determines the overall output. In figures, this means a loss of 20 to 30 per cent in the worst case. But it is not just the financial loss that is a problem: dirt can even damage the coating and seals, which can lead to total failure.

Problem

Good media resistance is very important for all bearing points in the cleaning robot, as they inevitably come into contact with cleaning agents. The components and bearing points must also be suitable for outdoor use and resistant to strong sunlight and changing weather conditions. The designers were looking for suitable bushes, especially for the bearing points in the wheels and brushes.

Solution

With iglidur ® P bearings, igus® has a solution with very good media resistance. As the bearings do not require external lubricants, neither dust nor dirt bind to the bearing points and no maintenance is required. In the brush, the designers use igubal ® ESFM flange bearings. Thanks to the spherical ball, they compensate for misalignment, are corrosion-free, extremely wear-resistant and also completely maintenance-free.

"In order to prevent wear between the two materials and thus increase the service life of the cleaning machine, we decided to use iglidur® P bearings from igus®."

Andreas Grochowiak

CEO of TG hyLIFT GmbH

Solar system cleaning as a challenge for operators

Regular cleaning of solar and photovoltaic surfaces is an absolute must, but it presents system operators and service providers with a major challenge. This is because the surfaces are difficult to access and sensitive, and cleaning must be extremely thorough. "The use of manual labour by personnel is a common solution here, which is dangerous and physically strenuous," explains Andreas Grochowiak, CEO of TG hyLIFT GmbH. The results are then also dependent on personnel and the effort required for several hundred square metres of solar surface is very high. The hyCLEANER black SOLAR promises simple, safe and, above all, up to five times faster cleaning than by hand, with only minimal water consumption. The machine is easy to operate by radio remote control and can effortlessly reach distances of up to 100 metres. It is no longer necessary to enter the sensitive roof and solar areas.

The hyCLEANER black SOLAR is used at the football stadium Stade de Suisse in Bern. There it regularly cleans more than 12,000 square metres of solar plant surface. (Source: TG hyLIFT GmbH)

The hyCLEANER moves by means of wheels on two plastic toothed belts, which are covered with special bands and generate their grip on the wet surface.

Lubrication-free polymer bearings for safe storage

The hyCLEANER moves forwards by means of four wheels on two plastic toothed belts. The belts are covered with special belts and develop their grip on the wet surface. This allows the hyCLEANER to travel on solar panels at an angle of up to 35 degrees and even cross maintenance aisles and gaps between the panels of up to 30 centimetres without any problems. The wheels, which drive the hyCLEANER via a plastic toothed belt, are made of POM material and are guided by a stainless steel shaft. "To prevent wear between the two materials and thus increase the service life of the cleaning machine, we decided to use iglidur® P bearings from igus®," explains Andreas Grochowiak. The material is specially designed for outdoor use and only absorbs very small amounts of moisture. It is highly resilient and has a low wear rate. Another advantage: like all igus® materials, it is lubricant and corrosion-free thanks to its polymer base.

Flange bearing for use in wet areas

All the user needs to start up the cleaning machine is a water connection. A reel ensures a simple and user-friendly hose management system over several metres. The solar surfaces are cleaned with water and a special 90 centimetre wide cleaning brush with a diameter of 30 centimetres. Thanks to the modular system of the hyCLEANER black SOLAR, other sizes can also be realised quickly and easily on request. The brush can rotate at up to 400 revolutions per minute. It is supported by an igubal® EFSM flange bearing, which is quickly and easily mounted on the shaft end of the brush and reliably compensates for misalignment. The spherical ball of the flange bearing is made of the high-performance plastic iglidur® W300, which is characterised by extremely high wear resistance and a long service life.

Andreas Grochowiak is convinced of the quality of the igus® bearing: "We have been relying on the lightweight plain bearing technology from igus® in our machines for several years now. This is successfully used, for example, in our hyCLEANER blue EVO series for cleaning glass and other surfaces and in the hyCLEANER red EVO series for cleaning façades."

To compensate for misalignments in the brush mounting, the designers used a square flange bearing made of lubrication-free high-performance plastic from igus.

Gerald Voß (left), Technical Sales Consultant of igus, together with Andreas Grochowiak (right), CEO of TG hyLIFT GmbH.

Successful in worldwide use

TG hyLIFT GmbH sells its cleaning systems worldwide and sees the best opportunities for its products in the future "The concept of cleaning solar systems in this way is still largely unknown in the industry, which is why we have to start here and convince both solar system operators and service providers from the facility management sector of our product," explains Grochowiak. The advantages are obvious: users save time and resources and increase the safety of their employees. The semi-automatic cleaning machine is used, for example, at the Stade de Suisse in Bern, where the hyCLEANER regularly cleans 12,000 square metres of solar surface. The solar system cleaning system is also used in modern architecture, such as at Arnhem Centraal railway station in the Netherlands and at the Marineda City shopping centre in Spain. Further projects are currently underway in Estonia and Spain. Always involved: the polymer bearings from igus®.