Pumping unit

Abstract

In the pumping unit disclosed, the friction acting on the impeller is reduced, and the efficiency is increased by at least two adjacent indentations of at least one face end of the impeller and/or of the at least one end wall of the pump chamber communicate with one another via a respective groove.

1 - 10 . (canceled) 
   
   
       11 . A pumping unit having an impeller disposed in a pump chamber and drivable to rotate by means of an actuator, the impeller comprising two face ends, an end wall of the pump chamber diametrically opposite each free end, a plurality of indentations providing hydrodynamic support in at least one of the face ends of the impeller and/or at least one of the end walls of the pump chamber, and a respective groove providing fluid communication between at least two adjacent indentations of the at least one face end and/or of the at least one end wall. 
   
   
       12 . The pumping unit as defined by  claim 11 , wherein the indentations and/or the grooves are disposed annularly. 
   
   
       13 . The pumping unit as defined by  claim 11 , wherein the indentations and/or the grooves extend in arclike, split-ringlike, oblong slot-like or similar form. 
   
   
       14 . The pumping unit as defined by  claim 11 , wherein the indentations and/or the grooves form a common ring. 
   
   
       15 . The pumping unit as defined by  claim 11 , wherein the indentations have a greater depth than the grooves. 
   
   
       16 . The pumping unit as defined by  claim 11 , wherein the indentations each have at least one face that is oblique with respect to the face ends and/or the end walls for hydrodynamic support of the impeller. 
   
   
       17 . The pumping unit as defined by  claim 16 , wherein the at least one oblique face, when the indentations are disposed on the impeller, is each provided on a trailing end of the indentation relative to a direction of rotation of the impeller. 
   
   
       18 . The pumping unit as defined by  claim 16 , wherein the at least one oblique face, when the indentations are disposed on the end walls of the pump chamber, is each provided on a downstream end of the indentation. 
   
   
       19 . The pumping unit as defined by claim  6 , wherein the indentations each have a lowest point that extends parallel to the at least one face end and/or end wall. 
   
   
       20 . The pumping unit as defined by  claim 11 , wherein the indentations of one face end of the impeller are diametrically opposite the indentations of the other face end of the impeller mirror-symmetrically relative to a middle face, and the indentations that are diametrically opposite mirror-symmetrically are joined together via a pressure equalization conduit.