Impeller for a centrifugal pump, a centrifugal pump and a use thereof

Abstract

An impeller for a centrifugal pump, the impeller includes a front shroud, a rear shroud, and one or more working vanes therebetween, the front shroud having a front face opposite to the face having the working vanes, the rear shroud having a rear face opposite to the face having the working vanes, the front shroud having an outer circumference and a plurality of front pump-out vanes attached to the front face of the front shroud, the rear shroud having a plurality of rear pump-out vanes attached to the rear face of the rear shroud, the front pump-out vanes being dimensioned in accordance with an equation: Σ i=1 z ( l i )/ D >8, where Z is the number of front pump-out vanes, l is the vane length measured along the leading surface of each front pump-out vane, D is the outer diameter of the front shroud.

1 . An impeller for a centrifugal pump, the impeller comprising:
 a front shroud, a rear shroud, and one or more working vanes therebetween, the front shroud having a front face opposite to the face having the working vanes, the rear shroud having a rear face opposite to the face having the working vanes, the front shroud having an outer circumference and a plurality of front pump-out vanes attached to the front face of the front shroud, the rear shroud having a plurality of rear pump-out vanes attached to the rear face of the rear shroud,   the front pump-out vanes being dimensioned in accordance with an equation:
   Σ i=1   z ( l   i )/ D> 8, where
 
   Z is the number of front pump-out vanes,   l is the vane length measured along the leading surface of each front pump-out vane,   D is the outer diameter of the front shroud.   
     
     
         2 . The impeller as recited in  claim 1 , wherein
 each front pump-out vane has a backward angle of inclination at the outer circumference of the front shroud equalling to less than 25°.   
     
     
         3 . The impeller as recited in  claim 1 , wherein
 the front pump-out vanes have a height of less than 2% of the diameter of the front shroud of the impeller.   
     
     
         4 . The impeller as recited in accordance with  claim 1 , wherein the front pump-out vanes have a height of 0.5-1.5% of the diameter of the front shroud of the impeller. 
     
     
         5 . The impeller as recited in accordance with  claim 1 , wherein
 the front pump-out vanes are of equal length, the vane length being l=0.9 . . . 1.1*D.   
     
     
         6 . The impeller as recited in accordance with  claim 1 ,
 the number of front pump-out vanes is 10.   
     
     
         7 . The impeller as recited in  claim 2 , wherein
 the backward angle of inclination of each front pump-out vane at the outer circumference of the front shroud is 22°.   
     
     
         8 . The impeller as recited in accordance with  claim 1 ,
 a cylindrical extension of the front face of the front shroud of the impeller, the cylindrical extension being configured to cooperate with a wear ring arranged to a volute casing of a centrifugal pump.   
     
     
         9 . A centrifugal pump using the impeller of  claim 1 . 
     
     
         10 . Use of the centrifugal pump of  claim 9  for pumping liquids and solids-containing liquids. 
     
     
         11 . Use of the centrifugal pump of  claim 9  for pumping fibrous suspension of pulp and paper or board industry.