Patent ID: 9599111
Date: 2017-03-21
CPC Classifications: F04D

Claim:
1. A molten metal pump comprising: an elongated body having a vertical tubular wall having an internal cavity defined by an inner wall terminating in a bottom end; and a first centrifugal impeller seated in an opening formed in a center of said bottom end; a second centrifugal impeller mounted coaxially with the first centrifugal impeller, wherein said second centrifugal impeller is a recirculation pump impeller; a pump motor which rotates a first drive shaft; a second drive shaft which is fixed to said first impeller; and a thermally resistive coupling mounted between and interconnecting said first drive shaft and said second drive shaft, wherein said coupling includes a plurality of radially spaced vanes which draw ambient air into and then out of said coupling as said coupling is rotated; and whereby rotation of the first impeller and the second impeller results in the ejected flow of molten metal from the first impeller to create an uplifting vortex which climbs the inner wall to an outlet opening passing through an upper portion of said body and simultaneously recirculating a bath of molten metal.