Pumps for pumping molten metal

Abstract

A nonmetallic pump for pumping molten metal includes a base with an impeller chamber, at least one molten metal inlet opening to the base, at least one molten metal outlet opening from the base, and an impeller connected to one end of a motor driven shaft and rotatable in the impeller chamber. The base includes an impeller opening in which the impeller is disposed and a wall extending so as to form a spiral-shaped opening around the impeller opening. An egress channel extends from the spiral-shaped opening toward the molten metal outlet opening.

What is claimed is:  
     
         1 . In a pump for pumping molten metal comprising a motor, a base, at least one molten metal inlet opening to said base, a molten metal outlet opening from the base, a shaft having a first end connected to the motor, and an impeller connected to a second end of the shaft and rotatable in an interior of said base, wherein said base, said shaft and said impeller are comprised of refractory material, the improvement wherein said base comprises an impeller opening in which said impeller is rotatably disposed, said impeller opening extending toward an end face of said base, a wall extending in the interior of said base so as to form a spiral shaped opening around said impeller opening, a recess disposed around said impeller opening and formed by a first surface which extends to and is integrally formed with said wall and a second surface which extends between said first surface and said end face, and a bearing ring disposed in said recess and disposed around said impeller opening.  
     
     
         2 . The pump of    claim 1    wherein said wall extends from said first surface to near an end of said impeller in a direction of said shaft and has load bearing support in a direction transverse to said shaft.  
     
     
         3 . The pump of    claim 2    wherein said end face forms a bottom surface of said base.  
     
     
         4 . The pump of    claim 3    wherein said wall extends away from said first surface in the direction of said shaft to near an upper end face of said impeller.  
     
     
         5 . The pump of    claim 1    wherein said spiral shaped opening extends so as to form a volute passage around said impeller whereby a pressure of molten metal increases as a result of traveling through said volute passage effective to enable said molten metal to be pushed through a tubular riser extending upward from said outlet opening at least to a height of said shaft.  
     
     
         6 . The pump of    claim 5    further comprising said tubular riser.  
     
     
         7 . The pump of    claim 5    wherein said outlet opening is a discharge opening at a side surface of said base.  
     
     
         8 . A base for a pump for pumping molten metal comprised of refractory material, said base comprising at least one molten metal inlet opening and a molten metal outlet opening, said inlet opening and said outlet opening communicating with an interior of said base, an impeller opening in which an impeller can be rotatably disposed, said impeller opening extending toward an end face of said base, a wall extending in the interior of said base so as to form a spiral shaped opening around said impeller opening, a recess disposed around said impeller opening and formed by a first surface which extends to and is integrally formed with said wall and a second surface which extends between said first surface and said end face, and a bearing ring disposed in said recess and disposed around said impeller opening.  
     
     
         9 . The base of    claim 8    wherein said wall extends from said first surface to near an end of said impeller in a direction of a rotational axis of said impeller and has load bearing support in a direction transverse to said axis.  
     
     
         10 . The base of    claim 9    wherein said end face forms a bottom surface of said base.  
     
     
         11 . The base of    claim 10    wherein said wall extends away from said first surface in the direction of said axis to near an upper end face of said impeller.  
     
     
         12 . The base of    claim 8    wherein said spiral shaped opening extends so as to form a volute passage around said impeller whereby a pressure of molten metal increases as a result of traveling through said volute passage effective enable said molten metal to be pushed through a tubular riser extending upward from said outlet opening at least to a height of a pump shaft.  
     
     
         13 . The base of    claim 12    wherein said outlet opening is a discharge opening at a side surface of said base.  
     
     
         14 . A one-piece insert for a base of a pump for pumping molten metal, said insert being formed of nonmetallic heat-resistant material and comprising an impeller opening that can receive an impeller, a wall extending so as to form a spiral-shaped opening around said impeller opening, and an egress channel that extends outwardly from said spiral-shaped opening.  
     
     
         15 . The insert of    claim 14    comprising a generally annular recess disposed around said impeller opening.  
     
     
         16 . The insert of    claim 15    comprising a generally annular bearing ring disposed in said recess.  
     
     
         17 . The insert of    claim 16    wherein said bearing ring is comprised of ceramic material.  
     
     
         18 . The insert of    claim 14    wherein said channel is generally rectangular shaped.  
     
     
         19 . The insert of    claim 14    wherein said channel is dimensioned so as to extend to a vertically extending surface forming an outlet opening in the base.  
     
     
         20 . The insert of    claim 14    wherein said channel is comprised of two elongated planar surfaces of said insert.  
     
     
         21 . In a pump for pumping molten metal including a motor, a base, at least one molten metal inlet opening to the base, a molten metal outlet opening from the base, a shaft connected to the motor at one end, and an impeller connected to the other end of the shaft and rotatable in an interior of said base, said base, said impeller and said shaft being comprised of refractory material, the improvement wherein said base comprises a one-piece insert formed of nonmetallic heat-resistant material disposed in the interior of said base, said insert comprising an impeller opening in which the impeller is disposed, a wall extending so as to form a spiral-shaped opening around said impeller opening and an egress channel that extends from said spiral-shaped opening toward said molten metal outlet opening.  
     
     
         22 . The improvement of    claim 21    comprising at least one pin extending through said base and into said insert.  
     
     
         23 . The improvement of    claim 21    wherein said egress channel extends outwardly from said spiral-shaped opening and is of a dimension sufficient to connect to the molten metal outlet opening whereby a continuous passageway exists for molten metal to flow from the molten metal inlet opening to the molten metal outlet opening.  
     
     
         24 . The improvement of    claim 21    wherein one of said base and said insert comprises a generally annular recess.  
     
     
         25 . The improvement of    claim 24    comprising a generally annular bearing ring disposed in said recess.  
     
     
         26 . The improvement of    claim 25    wherein said bearing ring is comprised of ceramic material.  
     
     
         27 . The improvement of    claim 21    wherein said interior of said base is of a configuration and size that can receive said insert.  
     
     
         28 . The improvement of    claim 21    wherein said support structure comprises a generally vertically extending transfer conduit for molten metal, said transfer conduit being disposed in said molten metal outlet opening.