System and method for melting light gauge metal stock

Abstract

An exemplary furnace system for melting stock metal includes a main hearth and a side well subsystem, which includes a melting well disposed downstream of the main hearth for receiving flow from the main hearth, an input flow inducer disposed upstream of the melting well and downstream of the main hearth, and an output flow inducer disposed downstream of the melting well and upstream of the main hearth. The input flow inducer drives molten metal into the melting well, thereby forming a differential metal head in the melting well. The output flow inducer evacuates molten metal from an output conduit, thereby reducing counter-pressure at an output port of the melting well communicating with the output conduit. This allows atmospheric pressure to add to the differential metal head in the melting well, resulting in an increase in productivity of the side well subsystem and of the furnace system as a whole.

What is claimed is: 
     
         1 . A method of melting and recovering metal with a furnace system, comprising the steps of:
 supplying a molten metal bath;   forcibly directing molten metal from the molten metal bath into a melting well at an input port of the melting well under motive force applied to the molten metal by an input flow inducer;   adding pieces of solid metal to the melting well, the pieces at least partially melting in the molten metal in the melting well, molten metal flowing out of the melting well via an output flow conduit, the output flow conduit having a first end opening to and fluidly coupled to the melting well at the output port of the melting well and the output flow conduit having a second end terminating at a discharge opening of the output flow conduit through which molten metal is discharged from the output flow conduit into the molten metal bath, the discharge opening of the output flow conduit upstream of a point in the furnace system from which molten metal is tapped or recovered, and the output flow conduit establishing an enclosed passage between the output port of the melting well and the discharge opening of the output flow conduit; and   forcibly evacuating molten metal from the output flow conduit using an output flow inducer configured to act on and apply motive force to molten metal located in the output flow conduit between the output port of the melting well and the discharge opening of the output flow conduit, the motive force resulting from an evacuating action in the output flow conduit established by the output flow inducer.   
     
     
         2 . The method of  claim 1 , wherein flow rate of the molten metal in the output flow conduit is a function of atmospheric pressure on the molten metal in the melting well and of a differential head of metal in the melting well established by a differential height of the metal in the melting well and in a reservoir containing the molten metal bath. 
     
     
         3 . The method of  claim 1 , wherein forcibly evacuating molten metal from the output flow conduit includes electromagnetically exciting the molten metal. 
     
     
         4 . The method of  claim 1 , wherein forcibly evacuating molten metal from the output flow conduit includes mechanically acting on the molten metal or directing gas at the molten metal. 
     
     
         5 . The method of  claim 1 , wherein forcibly evacuating molten metal from the output flow conduit includes magnetically driving the molten metal. 
     
     
         6 . The method of  claim 1 , wherein the output flow inducer reduces counter-pressure at the output port of the melting well. 
     
     
         7 . The method of  claim 1 , wherein a reservoir containing the molten metal bath is fluidly coupled to a main hearth of the furnace system in which heat energy is added to the molten metal. 
     
     
         8 . The method of  claim 1 , wherein adding pieces of solid metal to the melting well includes adding pieces of solid metal including aluminum. 
     
     
         9 . The method of  claim 1 , wherein supplying the molten metal bath includes supplying a reservoir of molten metal including aluminum. 
     
     
         10 . The method of  claim 1 , wherein a reservoir containing the molten metal bath includes at least one of a main hearth of the system in which heat energy is added to the molten metal or a pumping well at which the motive force is applied by the input flow inducer. 
     
     
         11 . The method of  claim 1 , further comprising controlling the input and output flow inducers to vary flow rate of molten metal in the furnace system.