Centriugal pump

Abstract

A centrifugal pump which includes a tubular structure which extends into an eye of an impeller and which directs a medium to be pumped into the eye, and wherein an axially extending annular cylindrical sealing clearance is formed between opposing surfaces of the impeller and the structure.

1 - 4 . (canceled) 
     
     
         5 . A centrifugal slurry pump ( 50 ) which includes a casing ( 52 ) which defines a volute ( 56 ) inside the casing ( 52 ), an impeller ( 58 ) mounted on a shaft ( 66 ) in the volute ( 56 ), for rotation about an axis ( 62 ), the impeller ( 58 ) including a centrally positioned eye ( 68 ), a front shroud ( 74 ) and a plurality of vanes ( 70 , 72 ) on the front shroud ( 74 ) which extend radially outwardly from the eye ( 68 ), and a structure ( 78 ) which is mounted to the casing ( 52 ) and which is configured to supply a medium to be pumped into the eye ( 68 ), characterized in that the structure ( 78 ) includes a tube ( 80 ) which is centered on the axis ( 62 ), a radially extending flange ( 82 ) on the tube ( 80 ) which forms a front liner ( 84 ) and which has an inner surface ( 86 ) which opposes the vanes ( 72 ) on the front shroud ( 74 ) and wherein a section ( 90 ) of the tube ( 80 ) which protrudes from the flange ( 82 ) has an outer seal surface ( 92 ) which extends circumferentially around the axis ( 62 ), which is parallel to the axis and which extends, at least partly, into the eye ( 68 ), and the impeller ( 58 ) includes an inner seal surface ( 100 ) which extends circumferentially around at least a part of the eye ( 68 ), and which is radially spaced from and which opposes the outer seal surface ( 92 ), whereby an axially extending annular sealing clearance ( 102 ) which is formed between the outer seal surface ( 92 ) and the inner seal surface ( 100 ), and a second sealing clearance ( 110 ) which extends outwardly from the axially extending annular sealing clearance ( 102 ), inhibit slurry, entering through the tube ( 80 ), from readily flowing to the vanes ( 72 ) on the front shroud ( 74 ). 
     
     
         6 . A centrifugal slurry pump ( 50 ) according to  claim 5  characterized in that the axially extending annular sealing clearance ( 102 ) is cylindrical with the outer surface ( 92 ) and the inner surface ( 100 ) which are spaced apart and which are parallel to each other and which are coaxial with the axis ( 62 ).