GB188717A - Improvements in or relating to screw propellers and axial flow impellers - Google Patents

Abstract

188,717. Gill, J. H. W. July 14, 1921. Screw propellers; propelling and steering by water jets.-An anti-fouling device for screw propellers, axial flow impellers and the like comprises an independent member, close to the intake side of the rotary member, provided with plates or blades which lie parallel to the direction of flow and arranged so that there is a progressive shearing action between the two members whereby weeds and like foreign matters are cut. The plates or blades may be mounted so as to have a limited rotational or axial movement and may be spring controlled. In front of the blades B of a screw propeller, a plate or plates D, Figs. 1 and 3, are placed parallel to the direction of flow. When the leading edges of the blades are straight. the plates are parallel in a plane radial to the boss, Fig. 1, when the edges are curved the plate may be in a radial plane, Fig. 3. The plates may be fixed to the ship's structure or carried by bosses on the propeller shaft. In a modification, the blade D instead of being fixed is carried by a bracket 0 which allows of limited rotational movement under the restraint of a spring member P, Fig. 12, attached to a hull fitting Q.