Adjustable blade runner hubs are typically filled with pressurized oil. This oil lubricates runner blade trunnion bearings and sliding parts of the operating mechanism in the hub. However, using hub oil endangers water pollution by oil spill from the hydroelectric facility. In order to eliminate this risk, Voith Hydro has been developing and installing oil-free solutions since 1985.
Pressurized oil has been replaced by selflubricating materials and assures not only the prevention of accidental releases of grease substances into the environment but also allows for easy maintenance, lower friction and good bearing perfor- mance without the necessity of increasing servo size.