Pumps and components therefor

Abstract

A pump side part for use with a shrouded pump impeller, comprising a side wall section rear face including an outer region with an outer edge in a plane which is substantially at right angles to the rotation axis, an inner region with an inner edge and an intermediate region between the outer and inner regions which is inclined inwardly from the said plane in a direction towards the inlet section, the inner region extending from the intermediate region in a direction away from the front face of the side wall section, wherein the outer face of the impeller front shroud and the side part rear face are arranged to be facing one another with a gap therebetween, the rear face being configured so that the cross-sectional dimension of the gap increases in a direction toward the impeller rotation axis in the intermediate region.

1 . In combination, a pump side part and a pump impeller,
 the impeller comprising a front shroud, a back shroud and a plurality of pumping vanes therebetween, the front shroud having an outer face and an impeller inlet extending through the front shroud, the impeller inlet being coaxial with an impeller rotation axis;   the pump side part comprising a side wall section having a front face and a rear face, the pump side part further comprising an inlet section extending from the front face and arranged when in use to be coaxial with the impeller rotation axis, the rear face including an outer region with an outer edge in a plane which is substantially at right angles to the rotation axis, an inner region with an inner edge and an intermediate region between the outer and inner regions the rear face cross-sectional profile in the intermediate region being inclined from the outer region outwardly with respect to the plane, and the rear face cross-sectional profile in the inner region being inclined inwardly from the intermediate region with respect to the plane,   wherein the outer face of the impeller front shroud and the rear face of the pump side part are arranged in use to be facing one another with a gap therebetween the gap having an outer opening and an inner opening, the rear face of the side wall section being configured so that the cross-sectional dimension of the gap increases in a direction toward the impeller rotation axis in the intermediate region, and the inner region terminating at the inner opening.   
     
     
         2 . The combination according to  claim 1 , wherein the dimension of the gap between the outer face of the impeller front shroud and the inner region of the rear face of the pump side part decreases in the direction from the intermediate region towards the inner edge. 
     
     
         3 . The combination according to  claim 2 , wherein the profile of said inner region comprises a continuous substantially uninterrupted inclined face. 
     
     
         4 . The combination according to  claim 2 , wherein the profile of said intermediate region comprises a continuous substantially uninterrupted inclined face. 
     
     
         5 . The combination according to  claim 4 , wherein the inclined face of one or both of the intermediate and inner regions is substantially linear. 
     
     
         6 . The combination according to  claim 4 , wherein one or both of the intermediate and inner regions is generally frusto conical in shape. 
     
     
         7 . The combination according to  claim 2 , further including a transition region between the intermediate and inner regions, the transition region being curved. 
     
     
         8 . (canceled) 
     
     
         9 . The combination according to  claim 1 , wherein the profile of the outer region, inner region and intermediate region are substantially linear, the outer region profile being substantially at right angles to the central axis. 
     
     
         10 . In combination, a pump side part and a pump impeller,
 the impeller comprising a front shroud, a back shroud and a plurality of pumping vanes therebetween, the front shroud having an outer face and an impeller inlet extending through the front shroud, the impeller inlet being coaxial with an impeller rotation axis;   the pump side part comprising a side wall section having a front face and a rear face, the pump side part further comprising an inlet section extending from the front face and arranged when in use to be coaxial with the impeller rotation axis, the rear face including an outer region with an outer edge in a plane which is substantially at right angles to the rotation axis, an inner region with an inner edge, and an intermediate region between the outer and inner regions which is inclined outwardly from the said plane in a direction towards the inlet section, the inner region being inclined and extending from the intermediate region in a direction away from the front face of the side wall section and a curved transition region between the inner and intermediate regions,   wherein the outer face of the impeller front shroud and the rear face of the pump side part are arranged in use to be facing one another with a gap therebetween the gap having an outer opening and an inner opening, the rear face of the side wall section being configured so that the cross-sectional dimension of the gap increases in a direction toward the impeller rotation axis in the intermediate region and wherein the dimension of the gap between the outer face of the impeller front shroud and the inner region of the rear face of the pump side part decreases in the direction from the intermediate region towards the inner edge, terminating at the inner opening.   
     
     
         11 . The combination according to  claim 10 , wherein the gap size in the transition region is determined by a constructed circle C generated in the transition region where the intermediate region and the inner region terminates at respective tangential points on the circumference of the circle, and the plane of the outer face of the impeller front shroud is tangential to another point on the circumference of the circle C, the diameter D of the circle C being in the range from 0.02 to 0.10 of the radial distance L between the outer diameter Z of the front shroud and an inner diameter Y of an innermost end of the inlet section of the pump side part. 
     
     
         12 . The combination according to  claim 11 , the diameter D of the circle C being in the range from 0.04 to 0.05 of the radial distance L between the outer diameter Z of the front shroud and an inner diameter Y of an innermost end of the inlet section of the pump side part. 
     
     
         13 . The combination according to  claim 11 , wherein the distance M from the centre of the circle C to the rotation axis X-X is from 1.0 to 1.8 of the diameter Y of the innermost end of the inlet section of the pump side part. 
     
     
         14 . The combination according to  claim 11 , wherein the distance M from the centre of the circle C to the rotation axis X-X is from 1.2 to 1.8 of the diameter Y of the innermost end of the inlet section of the pump side part. 
     
     
         15 . The combination according to  claim 11 , wherein the distance M from the centre of the circle C to the rotation axis X-X is from 1.2 to 1.5 of the diameter Y of the innermost end of the inlet section of the pump side part. 
     
     
         16 . The combination according to  claim 11 , wherein the impeller comprises a plurality of auxiliary vanes on the outer face of the front shroud, the auxiliary vanes being of a depth T, the diameter D of the circle C being in the range from 0.5 to 1.5 of the depth of the auxiliary vanes. 
     
     
         17 . The combination according  claim 11 , wherein the impeller comprises a plurality of auxiliary vanes on the outer face of the front shroud, the auxiliary vanes being of a depth T, the diameter D of the circle C being in the range from 0.5 to 1.0 of the depth of the auxiliary vanes.