Impeller system for molten metal pumps

Abstract

A molten metal pump and impeller system including an impeller body with a center portion with a shaft aperture therein, a plurality of vanes extending outward from the center portion, each vane including a radially inward end, a radially outward end, an input side, an output side, a leading surface, a trailing surface, a vane width between the leading surface and the trailing surface, and wherein the vane width is tapered from the input side to the output side. In another embodiment, the leading surface is convex notwithstanding whether the vane width is tapered.

I/We claim:  
     
         1 . A molten metal pump impeller system comprising: 
 an impeller body comprising, 
 a center portion with a shaft aperture therein;  
 a plurality of vanes extending outward from the center portion, each vane including a radially inward end, a radially outward end, an input side, an output side, a leading surface, a trailing surface, a vane width between the leading surface and the trailing surface; and  
 wherein the vane width is tapered from the input side to the output side.  
   
     
     
         2 . A molten metal pump impeller system as recited in  claim 1 , and further comprising an annular base at the output side of the plurality of vanes.  
     
     
         3 . A molten metal pump impeller system as recited in  claim 2 , and further wherein the entire vane width is tapered from the input side to the annular base.  
     
     
         4 . A molten metal pump impeller system as recited in  claim 1 , and further wherein the input side is the vertically upward side.  
     
     
         5 . A molten metal pump impeller system as recited in  claim 1 , and further wherein the plurality of vanes are tapered at the input side from the radially inward end to the radially outward end, thereby creating a shoulder on the radially outward end of the plurality of vanes.  
     
     
         6 . A molten metal pump impeller system as recited in  claim 1  and further wherein the leading surface is convex.  
     
     
         7 . A molten metal pump impeller system comprising: 
 an impeller body comprising: 
 a center portion with a shaft aperture wherein;  
 a plurality of vanes extending outward from the center portion, each vane including a radially inward end, a radially outward end, an input side, an output side, a leading surface, a trailing surface, a vane width between the leading surface and the trailing surface; and  
 wherein the leading surface is convex.  
   
     
     
         8 . A molten metal pump impeller system as recited in  claim 7 , and further comprising an annular base at the output side of the plurality of vanes.  
     
     
         9 . A molten metal pump impeller system as recited in  claim 8 , and further wherein the entire vane width is tapered from the input side to the annular base.  
     
     
         10 . A molten metal pump impeller system as recited in  claim 7 , and further wherein the input side is the vertically upward side.  
     
     
         11 . A molten metal pump impeller system as recited in  claim 7 , and further wherein the plurality of vanes are tapered at the input side from the radially inward end to the radially outward end, thereby creating a shoulder on the radially outward end of the plurality of vanes.