System and methodology to facilitate pumping of fluid

Abstract

A technique facilitates operation of a pump such as a multiphase pump. The pump may be provided with an impeller having a plurality of impeller blades. The impeller blades have blade tips which extend over an axial length. A ring is positioned along the blade tips to stiffen the impeller and to thus provide stability. However, the axial length of the ring is limited relative to the axial length of the impeller to enable flow, e.g. leakage, across the blade tips in a manner which causes active phase mixing during pumping of a fluid, e.g. a multiphase fluid.

What is claimed is: 
     
         1 . A system for moving fluid, comprising:
 a pump having a pump housing, a shaft rotatably mounted in the pump housing, and a plurality of impellers mounted to the shaft, each impeller comprising:
 an impeller hub rotationally fixed to the shaft; and 
 a plurality of impeller blades extending radially outward from the impeller hub, each impeller blade having an impeller base proximate the impeller hub and in impeller tip, the impeller tips having an axial length; and 
 a wear ring disposed along the tips of the impeller blades and having a wear ring axial length shorter than the axial length of the impeller tips. 
   
     
     
         2 . The system as recited in  claim 1 , wherein the wear ring axial length is less than 95% of the axial length of the impeller tips. 
     
     
         3 . The system as recited in  claim 1 , wherein the wear ring axial length is 10% to 95% of the axial length of the impeller tips. 
     
     
         4 . The system as recited in  claim 1 , wherein the pump comprises a plurality of diffusers alternating with the plurality of impellers. 
     
     
         5 . The system as recited in  claim 1 , wherein the wear ring is formed from a different material than the plurality of impeller blades. 
     
     
         6 . The system as recited in  claim 1 , wherein the wear ring extends radially outwardly of the impeller tips. 
     
     
         7 . The system as recited in  claim 6 , wherein the wear ring is received in a slot formed in a surrounding wall. 
     
     
         8 . The system as recited in  claim 1 , wherein the wear ring is provided with a seal surface having at least one of an annular seal shape; a labyrinth seal shape, a pocket damper seal shape; and a stepped diameter segmented seal shape. 
     
     
         9 . The system as recited in  claim 1 , wherein the wear ring is radially coextensive with the impeller tips. 
     
     
         10 . A system, comprising:
 a multiphase pump having an impeller mounted to a rotatable shaft, the impeller comprising:
 a plurality of impeller blades, each impeller blade having an impeller base and in impeller tip, the impeller tip having an axial length; and 
 a ring affixed to the tips of the impeller blades and having a ring axial length shorter than the axial length of the impeller tips. 
   
     
     
         11 . The system as recited in  claim 10 , wherein the impeller comprises a plurality of impellers disposed between corresponding diffusers to establish pump stages. 
     
     
         12 . The system as recited in  claim 11 , wherein the impellers are helico axial impellers. 
     
     
         13 . The system as recited in  claim 10 , wherein the ring is provided with a seal surface having at least one of an annular seal shape; a labyrinth seal shape, a pocket damper seal shape; and a stepped diameter segmented seal shape. 
     
     
         14 . The system as recited in  claim 10 , wherein the ring axial length is 10% to 95% of the axial length of the impeller tips. 
     
     
         15 . A method, comprising:
 providing a multiphase pump with an impeller having a plurality of impeller blades with blade tips extending an axial length;   securely positioning a ring along the blade tips to stiffen the impeller; and   limiting a ring axial length to less than the axial length of the blade tips to enable flow across the blade tips for active phase mixing.   
     
     
         16 . The method as recited in  claim 15 , wherein providing the multiphase pump with the impeller comprises providing a plurality of helico axial impellers. 
     
     
         17 . The method as recited in  claim 16 , wherein limiting comprises limiting the ring axial length to less than 95% of the axial length of the blade tips. 
     
     
         18 . The method as recited in  claim 15 , wherein securely positioning comprises positioning the wear ring at a desired location between an inlet side and an outlet side of the impeller. 
     
     
         19 . The method as recited in  claim 15 , further comprising providing features at a contact surface between the ring and the impeller blades to facilitate fluid flow and mixing. 
     
     
         20 . The method as recited in  claim 15 , further comprising providing the ring with a seal surface having at least one of an annular seal shape; a labyrinth seal shape, a pocket damper seal shape; and a stepped diameter segmented seal shape.