A robot that protects the oceans from contamination

Norwegian engineers launch environmentally friendly cleaning concept with lubrication-free igus plain bearing and linear technology

Stavanger, Norway

Robotic system for washing vessels and offshore platforms

Plain bearings, Linear guides and servo motor

Millions of tonnes of harmful substances from paints and varnishes end up in the oceans when operators maintain the surfaces of their vessels and offshore platforms with open-blasting methods. An environmentally friendly alternative: RoboCoat. With the help of the multi-functional robot from the Norwegian company Remotion, material residue is recycled. The lubrication-free linear guides and plain bearings from igus contribute to achieve this goal.

Surfaces of vessels and offshore platforms are exposed to saltwater and hence continuous corrosion. Therefore, operators have to replace paint and varnish regularly. So-called open-blasting processes are particularly popular for removing these layers. Their problem: material residue ends up in the water. Up to 2.25 million tonnes per year, as estimated by the World Economic Forum. “We are no longer planning to accept this tremendous environmental pollution”, says Morten Urrang, CEO of Remotion, which is headquartered in the Norwegian city Stavanger. “Therefore, we have developed a robotic system that washes surfaces of vessels and offshore platforms, UHP (Ultra high pressure) water blasts, sandblasts and varnishes them and disposes of material residue so that they do not pollute the environment. Developed in close co-operation with Aker BP, a Norwegian operator in the oil and gas industry.”

Material residue ends up in recycling facility via vacuum extraction

The Norwegian solution is called RoboCoat System. Its main feature: a carrier robot named Helios, which looks a bit like a lunar rover and climbs up vertical walls almost as skilfully as Spiderman. This is possible due to the permanent magnets, which press the wheels of the vehicle onto the vessel’s steel surface. This force is so strong that Helios can also carry tools. This can be a UHP water jet unit, that automatically removes old coatings – with a water jet of 40 litres per minute and a high pressure of 2,700 bar, which amounts to about a thousand times that of a car tyre. The highlight: to make sure that paint residue and microplastics don’t fall into the water, the engineers installed a vacuum extraction. A hose transports material residue and jet water into a filtering system on board the vessel. It separates varnish particles and saves the remains in a tank, so that they can be recycled. The other tools apply the same principle and can be replaced as part of a modular system. This also applies to the sandblasting head from the manufacturer Pinovo. Here, abrasives and dust get on deck via a vacuum line, where the system recycles the abrasives and stores the waste. This is also the case with the airless sprayer, which is equipped with an incorporated filter and an extractor to control spray and vapours. Urrang: “With these new tools, we can minimize the emission compared with the traditional surface treatment methods.”

High-performance polymers prevent contamination of the sea

igus composite bearing solutions were chosen many places in the tooling and the robot itself. Their low weight and low maintenance requirements made them ideal for this purpose. Robocat system is applied in a harsh environment, therefore it is crucial to apply components which don`t corrode. These self-lubricating polymers are used in the toothed belt axis of the drylin ZLW series, with which the robot can move tools. Tools like the colour spray head are mounted on a carriage, which based on plain bearings made of high-performance polymers moves up to three meters on a hard anodized aluminum profile – driven by a servo motor. Without a single drop of lubricating oil. However, not only the lubrication-free properties convinced the engineers of the drylin linear guide. “Guides and carriages are also compact and light. Their low mass reduce the load on the magnets which increases the payload of the robot”, explains Michael Hornung, International Product Manager for drylin Linear and Drive Technology. This factor should not be underrated for a vehicle that is supposed to adhere to steel surfaces with magnets. “drylin linear guides are ideal for precise adjustment and positioning tasks in very small spaces.”

“Polymer plain bearings are ideal for use in maritime systems”

Weight also plays an important role in another igus part that the Remotion engineers installed in Helios and their other robotic solutions. Beside the surface treating robot, Remotion has developed several robots for subsea applications where they can effectively replace traditional ROVs and divers. In the harsh subsea environment mostly the iglidur X polymer plain bearings are used. Just like the linear guides, the bearings made of high-performance polymer are lubrication-free, significantly lighter than conventional metal bearings, and also reduce the entire weight of the robot. Despite their low weight, they withstand compressive forces of up to 150MPa. Furthermore, they are wear-resistant in the temperature range of -100 up to +250°C. “In addition to this exceptional ruggedness, we were convinced by the fact that the bearings only absorb very low quantities of moisture and do not corrode”, says Csaba Moharos, project manager at Remotion. “The components are reliable and low-maintenance, and hence ideal for use in maritime systems.”

RoboCoat is currently under development and it just has been through its baptism of fire. Remotion tested the robot on a vessel in the Norwegian town Farsund. There, the electric helper worked on 30 square metres of surface per day – a multiple of what a worker is able to achieve. And later this summer the system was offshore on Alvheim FPSO (Floating Production and Storage Unit) performing more testes. “However, this does not mean that robots should replace people in the long term”, Urrang said finally. “Rather, we envisage a human-robot collaboration. It is supposed to relieve workers.”

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