Overflow vortex transfer system

1. A molten metal pump comprising an elongated tube having a base end, a top end and a longitudinal axis, said tube defining a pumping chamber, a shaft disposed within said tube and a centrifugal impeller rotatable by said shaft, said impeller including a bearing ring portion, said impeller disposed in said pumping chamber proximate said base end, the bearing ring portion of said impeller forming a bearing surface with said tube, said pumping chamber adjacent said impeller having a diameter at least 1.1 times a diameter of the impeller, said base end including an inlet and said top end including an outlet, a distance between said inlet and said outlet being at least three times a height of said impeller and less than 14 feet, and wherein said top end includes a chamber directing a flow of molten metal radially to said outlet.

2. The molten metal pump of claim 1 wherein said tube has a diameter of at least 1.5 times the diameter of the impeller.

3. The molten metal pump of claim 1 wherein said distance is at least ten times the height of the impeller.

4. The molten metal pump of claim 1 wherein said tube is comprised of a refractory ceramic.

5. The molten metal pump of claim 1 wherein said chamber includes a volute shape.

6. The molten metal pump of claim 1 wherein said outlet is tangential to a sidewall forming said chamber.

7. The molten metal pump of claim 1 wherein a metal frame surrounds at least a portion of said chamber.

8. The molten metal pump of claim 7 wherein a compressible material is disposed between said metal frame and said chamber.

9. The molten metal pump of claim 1 , wherein said chamber further includes a safety spillway.

10. The molten metal pump of claim 9 wherein said outlet comprises a channel in a side wall of said chamber, said channel having a depth substantially equal to a depth of said chamber.

11. The molten metal pump of claim 10 wherein said safety spillway comprises a channel having a depth less than a depth of said outlet channel.

12. The molten metal pump of claim 1 wherein said impeller includes a chamfered registration region shaped cooperatively to said inlet.

13. The molten metal pump of claim 1 wherein, in operation, molten metal is drawn into the impeller through the inlet and forced upwardly within the tube in the shape of a forced vortex.

14. The molten metal pump of claim 1 wherein said chamber has a diameter greater than the diameter of the tube intermediate said inlet and said outlet.

15. The molten metal pump of claim 1 wherein said bearing ring portion is disposed in said inlet.

16. A molten metal pump comprised of an elongated refractory body, said refractory body having an inlet region having an inlet diameter, a vortex region having a vortex region diameter, and an outlet region having an outlet region diameter, wherein said outlet region diameter is greater than said vortex region diameter, and said vortex region diameter is greater than said inlet region diameter, an impeller having at least a bearing ring portion disposed in said inlet and forming a bearing surface therewith, said impeller relative to the refractory body having a bottom inlet and side outlets, a shaft comprised of a refractory material extending through said vortex region and said outlet region and including a first end engaging the impeller and a second end adapted to engage a motor via a coupling.

17. The molten metal pump of claim 16 including an outlet channel intersecting said outlet region.

18. The molten metal pump of claim 16 wherein said vortex region has a height greater than a height of said inlet region and said outlet region.

19. The molten metal pump of claim 17 where said outlet region comprises a volute shape.

20. The molten metal pump of claim 16 wherein said side outlets are defined by a plurality of vanes.