Impeller For Centrifugal Blasting Wheel

Abstract

An impeller for a centrifugal blasting wheel includes a base plate, a support collar, and a plurality of spaced rotor blades interconnecting the base plate and support collar. A step is formed at the inner end of the collar and the outer ends of the rotor blades which causes blasting shot to be discharged to the throwing blades of the blasting wheel in a relatively more radial direction to reduce wear of the throwing blades. The base plate also has a frustum-shaped central boss formed to minimize wear of the base plate by the blasting shot. The frustum-shaped central boss has a recess formed therein so that the head of the bolt that connects the impeller to the throwing wheel is located entirely within the recess to also reduce wear of the bolt head.

1 . An impeller for feeding blasting shot to a centrifugal blasting wheel, comprising:
 (a) a base plate adapted for rotation about a central axis of rotation, said base plate extending substantially perpendicularly from said axis of rotation, and having an outer circumferential end radially spaced from said axis of rotation;   (b) a collar axially spaced from sais base plate and circumferentially surrounding said axis of rotation, said collar defining an interior circumferential surface and an exterior circumferential surface;   (c) a plurality of axially extending and circumferentially spaced apart rotor blades connecting the outer circumferential end of said base plate and said collar to thereby define a general cylindrically shaped interior space and a plurality of axially and circumferentially extending openings therebetween to permit discharging of blasting shot therethrough from said interior space upon rotation, and each of said rotor blades defining an inner circumferential surface and an outer circumferential surface; and   (d) a step for deflecting blasting shot exiting said interior space in a relatively more radial direction, said step defined by the outer circumferential surfaces of said rotor blades being disposed radially inwardly of the exterior circumferential surface of said collar.   
     
     
         2 . The impeller of  claim 1  wherein said step is concavely-shaped. 
     
     
         3 . The impeller of  claim 2  wherein said step is an arc of a circle having a radius of from about 2 inches to about 6 inches. 
     
     
         4 . The impeller of  claim 2  wherein said step is an arc of a circle having a radius of from about 3 inches to about 5 inches. 
     
     
         5 . The impeller of  claim 2  wherein said step is an arc of a circle having a radius of about 4.25 inches. 
     
     
         6 . The impeller of  claim 1  wherein said base plate has an annular inner surface facing said interior space, and said annular inner surface surrounds a frustum-shaped central boss which projects axially into said interior space. 
     
     
         7 . The impeller of  claim 6  wherein the frustum-shaped central boss of said base plate has an axially extending bolt-receiving opening formed therethrough. 
     
     
         8 . The impeller of  claim 7  wherein said bolt-receiving opening includes an annular recess for engaging a bolt head. 
     
     
         9 . The impeller of  claim 8  wherein said annular recess has an axial depth such that the bolt head is located entirely within the recess. 
     
     
         10 . The impeller of  claim 6  wherein said frustum-shaped central boss includes an annular wall sloping axially inwardly from said annular inner surface at an angle of from about 2 degrees to about 15 degrees with respect to said annular inner surface. 
     
     
         11 . The impeller of  claim 6  wherein said frustum-shaped central boss includes an annular wall sloping axially inwardly from said annular inner surface at an angle of from about 5 degrees to about 12 degrees with respect to said annular inner surface. 
     
     
         12 . The impeller of  claim 6  wherein said frustum-shaped central boss includes an annular wall sloping axially inwardly from said annular inner surface at an angle of about 10 degrees with respect to said annular inner surface.