Impeller wheel

Abstract

The present invention relates to a pump impeller ( 12 ) of a centrifugal or half axial type to be used in a pump for pumping liquids, wherein the impeller is arranged with one or several vanes ( 18 ), that the vanes are attached to cover discs ( 12, 16 ) on each side, forming a so called closed impeller wheel, characterized in that the leading edges ( 40 ) of the vanes are swept backwards at the inlet opening ( 42 ) in one of the cover discs ( 16 ) of the impeller.

1 . An impeller wheel ( 12 ) of a centrifugal or half axial type to be used in a pump for pumping liquids, wherein the impeller ( 12 ) is arranged with one or several vanes ( 18 ), that the vanes ( 18 ) are attached to cover discs ( 14 ,  16 ) on each side, forming a so called closed impeller wheel, that the leading edges ( 40 ) of the vanes ( 18 ) are placed generally in a plane perpendicular to the axis of rotation ( 10 ) of the impeller ( 12 ), at the inlet opening ( 42 ) in one of the cover discs ( 16 ), characterized in that the leading edges ( 40 ) of the vanes ( 18 ) are swept backwards at the inlet opening ( 42 ) in one of the cover discs ( 16 ) of the impeller in relation to the direction of rotation (R). 
   
   
       2 . Impeller wheel according to  claim 1 , wherein the leading edges ( 44 ) protrude somewhat out of the inlet opening ( 42 ), arranged and capable of co-operating with cutting means ( 50 ) arranged in a central inlet opening of the pump. 
   
   
       3 . Impeller wheel according to  claim 2 , wherein the cutting means constitute at least one narrowing section of the gap between the central inlet opening of the pump and the leading ledges ( 40 ) of the impeller. 
   
   
       4 . Impeller wheel according to  claim 1 , wherein the leading edges ( 40 ) are swept generally corresponding to a logarithmic spiral. 
   
   
       5 . Impeller wheel according to  claim 4 , wherein a sweep angle (α) of the leading edges ( 40 ) is Π/2−β, where β is the angle of the logarithmic spiral. 
   
   
       6 . Impeller wheel according to  claim 1 , wherein the sweep angle (α) of the leading edges ( 40 ) are in the region 40-60°. 
   
   
       7 . Pump comprising an impeller wheel according to  claim 1 .