Riserless recirculation/transfer pump and mixer/pre-melter for molten metal applications

Abstract

A pump for processing molten metal having an enlarged tubular body which houses a centrifugal lifting pump at its bottom end. The bottom end has a curved shape that aids in the formation and sustainability of: a) a forced vortex; b) a highly forced vortex; and c) a super forced vortex, depending on the application when it which receives the ejected molten metal from the lifting pump's impeller. The lifting pump is controlled to cause the vortex to climb up the inner wall of the body up to and out of an outlet formed in the upper end of the body. A recirculation centrifugal pump is mounted coaxially to and rotates with the lifting impeller.

1 . A molten metal pump comprising:
 an elongated body defining an internal cavity defined by an inner wall which terminates in a bottom end; and   a first centrifugal impeller seated in an opening formed in the center of said bottom end, wherein molten metal ejected from the impeller is received by the bottom end;   whereby rotation of the impeller results in the ejected flow of molten metal creating an uplifting momentum which climbs the inner wall to an outlet opening passing through an upper portion of said body.   
     
     
         2 . A pump as defined in  claim 1 , wherein said internal cavity has a curvature which aids in the formation and sustaining of one of the following vortices: a forced vortex; a highly forced vortex; and a super forced vortex. 
     
     
         3 . (canceled) 
     
     
         4 . (canceled) 
     
     
         5 . A pump as defined in  claim 1 , wherein the diameter of the vessel inner wall is from 1.5 to 4 times the outer diameter of the first impeller. 
     
     
         6 . A pump as defined in  claim 1 , wherein the outlet opening of said vessel is at least three feet to seven feet above the bottom end of the internal cavity. 
     
     
         7 . A pump as defined in  claim 1 , wherein the impeller is a centrifugal pump generating a high velocity mixed flow with a specific speed ranging from 1,000 to 3,000. 
     
     
         8 . A pump as defined in  claim 1 , further comprising:
 a pump motor which rotates a tubular motor shaft;   a gear box coupled to said motor shaft, which reduces the output speed of the motor and increases the torque from the motor; and   a drive shaft coupled at one end to said gear box and receiving said increased torque and extending concentrically down through the tubular motor shaft and fixed to said impeller.   
     
     
         9 . A pump as defined in  claim 1 , further comprising:
 a pump motor which rotates a first drive shaft;   a second drive shaft which is fixed to said impeller; and   a thermally resistive coupling mounted between and interconnecting said first and second drive shafts, 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.   
     
     
         10 . A pump as defined in  claim 2 , wherein said forced vortex has a constant angular velocity. 
     
     
         11 . A pump as defined in  claim 10 , wherein said forced vortex has a curved shaped pressure distribution given by P/γ=C 2 r 2 /2g+h. 
     
     
         12 . A pump as defined in  claim 2 , wherein said highly forced vortex and said super forced vortex have a curved shaped pressure distribution given by P/γ=C 2 r 3 /3g+h; wherein said highly forced vortex has a flow rate of less than 1,000 gallons per minute and said super forced vortex has a flow rate greater than 1,000 gallons per minute. 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . A powertrain for a molten metal pump having drive motor which rotates a centrifugal impeller, comprising:
 a hollow tubular motor shaft which rotates with a rotor of said drive motor;   a mechanical gear train coupled at a first end to said motor shaft, wherein said gear train reduces the output speed of said drive motor and increases the torque transmitted; and   a cylindrical output shaft which is coupled to a second end of said gear train, wherein said output shaft rotates at said reduced output speed and receives said increased torque, wherein said output shaft is passes through said hollow motor shaft and is fixed to said impeller.   
     
     
         26 . A molten metal pump comprising:
 an elongated body defining an internal cavity defined by an inner wall which terminates in a bottom end; and   a first centrifugal impeller seated in an opening formed in the center of said bottom end and mounted upon a rotatable shaft, wherein molten metal ejected from the impeller is received by the bottom end;   a flow influencing element mounted above the first centrifugal impeller and in rotational engagement with the shaft; and   whereby rotation of the impeller results in the ejected flow of molten metal creating an uplifting momentum which climbs the inner wall to an outlet opening passing through an upper portion of said body.   
     
     
         27 . The molten metal pump of  claim 1 , further including a mechanism for introducing inert gas to said internal cavity. 
     
     
         28 . The molten metal pump of  claim 1 , further comprising a splash protector.