A scrap melting system and method includes a vessel that is configured to retain molten metal and a raised surface about the level of molten metal in the vessel. Solid metal is placed on the raised surface and molten metal from the vessel is moved upward from the vessel and across the raised surface to melt at least some of the solid metal. The molten metal is preferably raised from the vessel to the raised surface by a molten metal pumping device or system. The molten metal moves from the raised surface and into a vessel or launder.

A scrap melting system and method includes a vessel that is configured to retain molten metal and a raised surface about the level of molten metal in the vessel. Solid metal is placed on the raised surface and molten metal from the vessel is moved upward from the vessel and across the raised surface to melt at least some of the solid metal. The molten metal is preferably raised from the vessel to the raised surface by a molten metal pumping device or system. The molten metal moves from the raised surface and into a vessel or launder.

The present invention is directed to a molten metal pump comprising an elongated pumping chamber tube with a base end and an open top end. A shaft extends into the tube and rotates an impeller therein, the impeller rotates proximate the base end. The tube has a diameter at least 1.1 times the diameter of the impeller. The pumping chamber tube preferably has a length at least three times the height of the impeller. The base end includes an inlet and the top end includes a tangential outlet. Rotation of the impeller draws molten metal into the pumping chamber and creates a rotating equilibrium vortex that rises up the walls of the pumping chamber. The rotating vortex adjacent the top end exists the device cia the tangential outlet.

A molten metal pump assembly and method to fill a mold with molten metal, such as aluminum. The assembly includes a support frame for suspending the molten metal pump above a furnace. The support frame includes a mechanism for lifting and lowering the molten metal pump into engagement and disengagement with the mold.

A pump for transferring molten metal is provided. The pump includes a motor, a base having an impeller chamber, a shaft connected to the motor at one end, an impeller connected to the other end of the shaft and rotatable in the impeller chamber, and a riser disposed on an upper surface of the base. The base includes a shaft opening and an outlet opening in a top surface. The riser assembly has a first open end facing the base. The first open end is dimensioned to encompass the shaft opening and the outlet opening.

A smart molten metal pump system and method automatically controls the operating speed of the pump rather than requiring an operator to control the speed. The system includes a pump, a controller for controlling the speed of the pump, and one or more of a temperature sensor (such as a thermocouple), one or more of a device (such as a laser or float) to measure the depth of the molten metal, and one or more of a vibration sensor (such as an accelerometer) to measure vibration. The controller receives input about the temperature of the molten metal, and/or about the depth of the molten metal, and/or about the vibration of the pump or one or more pump components, and possibly other data. The controller analyzes the one or more inputs to vary the speed of the pump, turn the pump off, and/or send a communication to an operator.

A molten metal rotor receives and retains an end of a molten metal rotor shaft. The rotor shaft has one or more projections at the end received in the rotor. The rotor has an inner cavity, a top surface with an opening leading to the inner cavity, and at least one abutment. The opening includes one or more portions for allowing each projection to pass through the opening and into the inner cavity. The rotor and/or shaft are then rotated so at least one of the outwardly-extending projections is under the top surface of the rotor and is against an abutment. A molten metal pump, rotary degasser scrap melter or other device used in molten metal may utilize a rotor/shaft combination as disclosed herein.

One or more embodiments of the present invention relate to a pump/heat exchanger assembly of a nuclear reactor, in particular a liquid metal cooled nuclear reactor, the pump being characterized in that the shaft for driving the impeller is inserted in an shell inside the heat exchanger and has a smaller cross section at the bottom part of the tube bundle of the heat exchanger and a cross section that gradually increases up to a widest cross section at the top part of the tube bundle of the heat exchanger. The resulting axial profile of the impeller's shaft is, at the same time, designed to uniformly distribute the flow of the primary fluid inside the tube bundle of the heat exchanger and to provide high mechanical inertia to the pump.

A scrap melting system and method includes a vessel that is configured to retain molten metal and a raised surface about the level of molten metal in the vessel. Solid metal is placed on the raised surface and molten metal from the vessel is moved upward from the vessel and across the raised surface to melt at least some of the solid metal. The molten metal is preferably raised from the vessel to the raised surface by a molten metal pumping device or system. The molten metal moves from the raised surface and into a vessel or launder.

Embodiments of the invention are directed to a rotor for a molten metal pump and a molten metal pump including the rotor. The rotor has a main body and a top comprised of a material that is at least twice as hard as the main body. The top, among other things, may form a first portion of each rotor blade wherein the first portion directs molten metal into a pump chamber or other structure in which the rotor is mounted.