Pump for moving metal in a bath of molten metal

An apparatus for moving a stream of molten metal, comprising:

• a pumping member;
• a housing at least partially enclosing the pumping member;
• a power device;
• a shaft connecting the power device and the pumping member, said shaft having an elongated drive element and an elongated shield assembly, the shield assembly surrounding and forming a space between the drive element and the shield assembly sufficient to permit thermal expansion of the drive element;
• the shield assembly;
• comprising:
• an outer tubular shield connected to the pumping member;
• an inner tubular shield telescopically disposed in the outer shield;
• said inner tubular shield surrounding said drive element;
• an elongated graphite member disposed between said inner and outer tubular shields;
• and further including
• a tongue (58) carried on the lower end of the drive element (24) and secured to the pumping member;
• and
• cement disposed in the outer shield to provide a socket accommodating said tongue, the tongue being disposed in said socket but having a clearance therebetween to accommodate the relative thermal expansion characteristics of said tongue, but permitting the tongue to be rotated to engage the socket to rotate the pumping member.

An elongated support suited for positioning a pump in a bath of molten metal, comprising:

• a housing of a material that is resistant to the heat of the molten metal, said housing having an internal chamber;
• means for introducing an inert gas into said internal chamber;
• a structure, including a graphite shield, disposed in the internal chamber;
• and
• said structure having a tendency to be combustible in the presence of oxygen and non-combustible in the presence of an inert gas at such times as the housing is at least partially disposed in the bath of molten metal.

Apparatus for moving a stream of molten metal in a bath of molten metal, comprising:

• a pumping member adapted to be disposed in a bath of heated molten metal and to move a stream of molten metal as the pumping member is driven in a path of pumping motion;
• a power device adapted to be supported above the bath of molten metal and to be actuated in a powered motion;
• means for connecting the power device to the pumping member to move the pumping member in said path of pumping motion;
• a pump housing having a pumping chamber and a bottom inlet opening, the pumping member being disposed in the pump housing, the bottom inlet opening being adapted for receiving molten metal into said pumping chamber;
• the pumping member having a strainer plate having apertures for receiving molten metal into the pumping chamber as the pumping member is being rotated about an axis of rotation;
• a slinger rib mounted on the strainer plate adjacent the apertures and upstream thereof so as to strike debris carried in a stream of molten metal toward the apertures, in a direction away from said inlet opening as the pumping member is being rotated;
• and
• the pump housing having feet for supporting the pump housing above the floor of a pot containing molten metal such that the bottom inlet opening faces toward the floor of the pot when receiving molten metal therein.

Apparatus for moving a stream of molten metal in a bath of molten metal comprising:

• a pumping member adapted to be disposed in a bath of heated molten metal and to move a stream of molten metal as the pumping member is driven in a path of pumping motion;
• a power device adapted to be supported above the bath of molten metal and to be actuated in a powered motion;
• means for connecting the power device to the pumping member to move the pumping member in said path of pumping motion;
• a pump housing having a pumping chamber and an inlet opening, the pumping member being disposed in the pump housing, the inlet opening being adapted for receiving molten metal into said pumping chamber;
• the pumping member having a strainer plate in the inlet opening, having apertures for receiving molten metal into the pumping chamber as the pumping member is being rotated about an axis of rotation;
• a slinger rib mounted on the strainer plate adjacent the apertures and upstream thereof so as to strike debris carried into a stream of molten metal toward the apertures, in a direction away from said inlet opening as the pumping member is being rotated;
• and
• the pumping member having pumping vanes for moving the molten metal, the vanes having vane openings therebetween greater than the strainer apertures, whereby debris passing through the inlet opening is smaller than the vane openings between the vanes.

A shaft comprising:

• an outer tubular shield having a lower end attached to a pump housing;
• an inner tubular shield telescopically disposed in said outer tubular shield and being cemented thereto;
• a pumping shaft;
• the inner tubular shield having a bore with a diameter greater than the diameter of the pumping shaft, and enclosing the pumping shaft so as to form a chamber therearound;
• the lower end of the inner tubular shield being spaced from the lower end of the outer tubular shield to form a shoulder;
• a structure disposed adjacent the lower end of the pumping shaft having a diameter greater than the diameter of the bore of the inner tubular shield but less than the diameter of the outer shield, and the structure engages the shoulder to locate the lower end of the structure with respect to the inner tubular shield;
• and
• cement disposed in the lower end of the outer shield with a socket accommodating the configuration of the structure but having a clearance therebetween to accommodate the relative thermal expansion characteristics of said structure, but permitting the structure, to be rotated in the socket to rotate the pumping shaft.

A shaft for a molten metal pump comprising:

• an elongated drive element and an elongated shield assembly, the shield assembly having a monolithic closed end surrounding, and forming a space between the drive element and the shield assembly sufficient to permit thermal expansion of the drive element;
• the shield assembly including:
• an outer tubular shield;
• an inner tubular shield telescopically disposed in the outer tubular shield;
• said inner tubular shield surrounding said drive element;
• an elongated graphite member disposed between said inner tubular shield and said outer tubular shield;
• a drive structure supported on the lower end of the graphite member and connected to the pumping member;
• and
• cement disposed in the outer tubular shield to provide a socket accommodating a portion of said drive element extending out of said inner tubular shield, the drive element being disposed in said socket but having a clearance therebetween to accommodate the relative thermal expansion characteristics of said drive structure, but permitting the drive structure to be rotated to engage the socket wall to rotate a pumping member.

A shaft for a molten metal pump comprising:

• an elongated drive element and an elongated shield assembly, the shield assembly being so attached to the drive element as to be rotatable therewith as a unit, the shield assembly further comprising:
• an inner tubular shield having a bore with a diameter greater than the diameter of the drive element, and enclosing the drive element to form a chamber therearound sufficient to permit thermal expansion of the drive element;
• an outer tubular shield having a monolithic closed lower end surrounding the drive element and the inner tubular shield;
• a tongue extending from said drive element below said inner tubular shield;
• at least one of said inner tubular shield and said tongue being secured to said outer shield;
• and
• said outer shield being secured to a pumping member.