To start the washing process, the wind turbine rotor is locked in position with the lower blade lined up with the tower. The blade washing machine is lifted by mobile crane to the level of the blade tip and clamped around it. From there it crawls its way slowly up to the root washing as it goes, with the operator of the machine remotely controlling the process. Censors control water pressure from the spray nozzles and measure the blade area to avoid overuse of water and the environmentally friendly cleaning materials. Waste water is collected in tanks on the machine. On its journey back down to the tip, the machine waxes and polishes the entire surface area "to improve the blade efficiency and lifetime further."
The advantages offered by the system, says the company, are no blade corrosion caused by high pressure water, no blade damage from hard manual cleaning and no need for an external power source. Furthermore, collection of the washing liquid in tanks is environmentally friendly and the speed with which a rotor can be washed by a small team saves both time and money.
Together with Force Technology, a private Danish institution, BWM is also working on offering advanced ultrasonic scanning of the blade's structural condition as part of the washing process. All blades could be scanned for delamination or other defects before their warranty expires, suggests the company. Early warning of blade damage could save a blade breakage and the severe risk that the other blades, or the entire turbine, are damaged as well.