Composite impeller wheel with improved centering of one component on the other

A composite impeller of a flow machine composed of a forwardly extending component and a radially extending component axially aligned with each other in close proximity and each having vanes which register edgewise with the vanes of the other, the vanes of the forwardly extending component being shaped to operate with axial flow of a flow medium and the vanes of the radially extending component being shaped to operate with radial flow of said flow medium, said impeller incorporating also the combination of features consisting in that:

• both said forwardly extending component and said radially extending component have axial bores and are mounted on a common shaft that passes completely through both of them, said shaft having a tapered surface facing the narrowest portion of the bores of said components, with the diameter decreasing forwardly;
• said radially extending component (2) has an annular forward extension (9) concentric with said shaft (8) and said forwardly extending component (1) is firmly mounted and centered on said shaft and has a recess (10) into which said forward extension (9) of said radially extended component fits for centering said radially extending component on said forwardly extending component (1);
• said forwardly extending component (1) is shrink-fitted onto said forward extension (9) of said radially extending component (2);
• a sleeve (7) is interposed between the tapered portion of said shaft and said bores of said components and wedged firmly therebetween for centering said forwardly extending component and transmitting driving force between said shaft and at least said forwardly extending component, and
• in the region adjacent to the base of the vanes (3,4) the substantially transverse end surface of one component facing the other component has at least two radially running grooves and the facing end surface of the other component has at least two gripping claw ridges (11) each extending into one of said grooves, said grooves being longer than said ridges to allow relative radial movement.