Abstract: The invention relates to an impeller for a Kaplan turbine, comprising the following features or components: a shaft, a plurality of blades; a hollow hub which is located on the free end of the shaft and which carries the blades; an adjustment device for rotating the blades around axes of rotation perpendicular to the axis of rotation of the shaft. The invention is characterized by the following features: the interior of the hub is connected to a source of compressed air; branch lines are provided inside the hub to supply the compressed air to bearings or other lubrication points for the adjustment device.