Jet pump having unevenly spaced blades

Abstract

The invention is directed to a thick stator vane that effects continuous acceleration of the water stream within the jet pump, a non-uniform spacing of stator vanes or impeller blades to reduce noise output of the jet pump during operation, and a coupling structure positioned between the impeller and engine that prevents transfer of axial thrust to the engine caused by jet pump failure.

What is claimed is:  
     
         1 . A stator for use in a jet pump having an impeller rotatably coupled with respect to the stator, comprising: 
 a central hub portion; and    a plurality of stator vanes extending outward from the central hub portion arranged with irregular spacing between adjacent vanes, such that at least one stator vane is spaced from an adjacent stator vane a different distance than that stator vane is spaced from its other adjacent stator vane.    
     
     
         2 . A watercraft comprising: 
 a) a hull;    b) an engine supported by the hull; and    c) a jet pump supported by the hull, the jet pump including an impeller, and the stator of  claim 1 .    
     
     
         3 . An impeller for use in a jet pump having a stator fixed with respect to the impeller, comprising: 
 a) a central hub portion operatively connectable to an engine to rotate the central hub portion; and    b) a plurality of impeller blades extending outward from the central hub portion arranged with irregular spacing between adjacent blades, such that at least one impeller blade is spaced from an adjacent impeller blade a different distance than that impeller blade is spaced its other adjacent impeller blade.    
     
     
         4 . A watercraft comprising: 
 a) a hull;    b) an engine supported by the hull; and    c) a jet pump supported by the hull, the jet pump including a stator, and the impeller of  claim 3 , wherein the central hub portion is operatively connected to the engine.    
     
     
         5 . A jet pump comprising: 
 a) an impeller having: 
 a central hub;  
 a plurality of impeller blades extending outward from the central hub portion arranged with irregular spacing between adjacent blades, such that at least one impeller blade is spaced from an adjacent impeller blade a different distance than that impeller blade is spaced its other adjacent impeller blade;  
   b) a stator, fixed with respect to the impeller, having: 
 a central hub portion; and  
 a plurality of impeller blades extending outward from the central hub portion arranged with irregular spacing between adjacent blades, such that at least one impeller blade is spaced from an adjacent impeller blade a different distance than that impeller blade is spaced its other adjacent impeller blade.  
   
     
     
         6 . A watercraft comprising: 
 a) a hull;    b) an engine supported by the hull;    c) the jet pump of  claim 5 , wherein the central hub portion of the impeller is operatively connected to the engine.