Shrouded propeller ship propulsion system - comprises drive shaft and propeller with hub screw vanes and central bore

摘要

On the propellor hub (1) are two or more screw vanes (4) which are connected to a short cover nozzle or shroud (3). The central bore in the hub is connected to an air suction channel (5) in the hollow drive shaft (6). Outside the water surface, the drive shaft has suction holes (7), whereby the air suction channel of the drive shaft is in connection with the atmosphere. The screw vanes (4) driven by the drive shaft (6) produce a thrust by reason of their pitch which sets the vessel in motion. At the same time, they produce a swirl field and a vacuum which expand circularly in an axial direction as a turbulent flow which has a disadvantageous influence on the drive effect. The vacuum produced by the cover nozzle (3) sucks in an air current through the hollow drive shaft. This current fills the vacuum area in the backflow produced by the vanes, and causes a balanaced drive effect. USE/ADVANTAGE - Shrouded ships propeller with hollow shaft can compensate the swirl drag of a ship hull during forward drive, and produce a more balanced speed effect from the propulsion machinery.