US Patent 7845200 Drain pump

Drain pump for clothes washing machines, comprising: an impeller having vanes (7) that are arranged on respective planes passing through the axis of said rotating shaft, said drain manifold being provided with a planar inner wall (9), in which there is provided a hollow space or separating gap (20) between said vanes of the pump impeller and said planar inner wall of said drain manifold, in which there are arranged a plurality of planar members (22) provided integral with said impeller and arranged in respective planes extending parallel to the axis of said rotating shaft (6). Said planar members have a height that is smaller than the height of said vanes, but greater than the largest radius of the central hub of said rotating shaft.