Underwater sand and gravel extractor - has hydraulic motor driven bucket wheel with pressurised oil supplied to bearings to exclude dirt

摘要

The free-flowing material extraction equipment is particularly for underwater sand and gravel, having a bucket wheel driven by hydraulic motor at the end of the material extraction pipe. The wheel has a central collector chamber, connected to the pipe in the axial direction, and permanently open in the radial direction to all buckets. The prevent the ingress of dirt, the bearings are supplied with oil under pressure from the hydraulic motor, and a barrier medium under pressure, particularly water, is delivered between labyrinth and ring-type seals on the bucket wheel (12). The oil can be the leak-off oil from the motor.