All wind turbines require an emergency brake to stop them from rotating at dangerous speeds. The traditional solution is a disc brake, but that entails several problems in an offshore environment, such as heat dissipation and reliability.
The solution for which the US Patent and Trademark Office has now granted a patent, slows the turbine by using its rotation to move water. According to one implementation of the solution, a jacket mounted on the stationary generator housing is partly lowered into the water like a diving bell. On the rotating part of the turbine, fins are mounted that as long as the brake has not been activated, rotate in the air under the jacket. When the brake is activated, the air inside the jacket is evacuated through valves at the top. This means that the fins, instead of rotating in air, start moving water up through the jacket and out through the valves. The much greater resistance in the water thus slows the rotational speed of the turbine. It should be noted that the patented solution is conceptual and not limited to a particular implementation.
“We continue our long-term strategic work of building and broadening our patent portfolio. It protects our innovations and gives a stronger position in the market”, says Peter Laurits, CEO of SeaTwirl.