Molten metal pump and furnace for use therewith

Abstract

A metal melting closed furnace which includes a main chamber, a circulation wall connected to the main chamber by a communications passageway and a vortex well having a exit outlet for molten metal into the main chamber. A cover is emplaced over the vortex well. An inert gas bubble activated molten metal pump is provided in which there is an entry port in the circulation well and exit port tangentially arranged with respect to the periphery of the cavity. This exit port will typically be at or near the top of the vortex well. In order to reduce oxidation, inert gas bubbles are captured from this molten metal pump and are transported to an inert gas atmosphere or blanket above the molten metal vortex.

What is claimed is:  
     
         1 . A metal-melting furnace comprising: 
 a main chamber;    a circulation well connected to the main chamber by a communication passageway;    a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    a containment means emplaced over the vortex well;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well; and    a continuously or intermittently replenished inert gas atmosphere positioned in the vortex well beneath the cover.    
     
     
         2 . The furnace of  claim 1  wherein means are provided to recover inert gas from the molten metal pump for use in the inert gas atmosphere.  
     
     
         3 . The furnace of  claim 2  wherein the molten metal pump has a passageway extending into the vortex well and there is at least one inert gas bubble in said passageway and adjacent said vortex well there is a recess adjacent said vortex well which is separated from said passageway by a plate with at least one aperture so that at least some of the inert gas from said bubbles enters the recess and then the vortex well as said bubble passes the aperture.  
     
     
         4 . The furnace of  claim 1  wherein the vortex well is a separate and replaceable block of refractory material.  
     
     
         5 . The furnace of  claim 1  wherein the vortex well is in a refractory well block and there is a peripheral space between the cover and said refractory well block.  
     
     
         6 . The furnace of  claim 5  wherein metal chips mixed with volatile hydrocarbons are added to the vortex well and volatile hydrocarbons are removed through said space between said cover and said refractory well block.  
     
     
         7 . The furnace of  claim 1  wherein the molten metal recovered from the vortex well is removed to an intermediate well.  
     
     
         8 . The furnace of  claim 7  wherein molten metal from the intermediate well is re-circulated back to the main chamber.  
     
     
         9 . The furnace of  claim 1  wherein a feed tube extends through the containment means to enable metal chips to be tangentially added to the vortex well.  
     
     
         10 . The furnace of  claim 9  wherein the vortex well and the molten metal pump are contained in a well block and an adjoining end block which are connected by a projection from one of said blocks which engages a recess in said other block.  
     
     
         11 . The furnace of  claim 1  wherein the containment means is a cover and the vortex circulation well contains molten metal having a surface level and there is a sensor for measuring said surface level the cover is vertically displaceable to a position selected based upon said molten metal surface level.  
     
     
         12 . The furnace of  claim 11  wherein the cover is fixed to a feed tube and the cover and feed tube are vertically displaceable together.  
     
     
         13 . The furnace of  claim 1  wherein the vortex well has upwardly extended walls and the containment means comprises said upwardly extended walls of the vortex well.  
     
     
         14 . The furnace of  claim 1  wherein the inert gas is selected from the group consisting of nitrogen and argon.  
     
     
         15 . The furnace of  claim 1  wherein there is a molten metal vortex in the vortex well.  
     
     
         16 . The furnace of  claim 14  wherein vortex contains a molten metal selected from the group consisting of aluminum, magnesium, zinc, copper, brass, and steel.  
     
     
         17 . In a metal-melting furnace comprising: 
 a main chamber;    a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    a containment means emplaced over the vortex well; and    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well,    wherein the improvement comprises a continuously or intermittently replenished inert gas atmosphere positioned in the vortex well beneath the cover.    
     
     
         18 . The furnace of  claim 17  wherein means are provided to recover inert gas from the molten metal pump for use in the inert gas atmosphere.  
     
     
         19 . The furnace of  claim 18  wherein the molten metal pump has a passageway extending into the vortex well and there at least one inert gas bubble in said passageway and adjacent said vortex well there is a recess from said vortex well which is separated from said passageway by a plate with at least one aperture so that at least some of the inert gas from said bubbles enters the recess and then the vortex well as said bubble passes the aperture.  
     
     
         20 . A furnace of  claim 17  wherein the vortex well is in a refractory well block and there is a peripheral space between the cover and said refractory well block.  
     
     
         21 . The furnace of  claim 20  wherein metal chips mixed with volatile hydrocarbons are added to the vortex well and volatile hydrocarbons are removed through said space between said cover and said refractory well block.  
     
     
         22 . The furnace of  claim 17  wherein the vortex well has a bottom exit outlet and molten metal is removed to a circulation well from the main chamber before being removed to the vortex well and said molten metal is then removed from said bottom exit outlet with said vortex well to an intermediate well.  
     
     
         23 . A metal-melting furnace comprising: 
 a main chamber;    a circulation well connected to the main chamber by a communication passageway;    a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    a containment means emplaced over the vortex well;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well and the molten metal pump has a passageway extending into the vortex well and there is at least one inert gas bubble in said passageway and adjacent said vortex well there is a recess from said vortex well which is separated from said passageway by a plate with at least one aperture so that at least some of the inert gas from said bubbles enters the recess and then the vortex well as said bubble passes the aperture.    
     
     
         24 . A process for melting metal in a furnace comprising: 
 providing a main chamber containing molten metal and heating said molten metal in said main chamber;    providing a circulation well connected to the main chamber by a communication passageway and recovering molten metal from the main chamber through said communication passageway into said circulation well;    providing a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    providing a containment means and emplacing said containment means over the vortex well;    providing an inert gas bubble actuated molten metal pump having an exit port tangentially arranged with respect to the periphery of said vortex well or near the top of the vortex well and forming in said molten metal pump a plurality of inert gas bubbles for recovering molten metal from the circulation well to the vortex well; and    forming and continuously or intermittently replenishing an inert gas atmosphere in the vortex well beneath the containment means.    
     
     
         25 . The process of  claim 24  wherein inert gas bubbles in the molten metal pump is recovered for use in the inert gas atmosphere.  
     
     
         26 . The process of  claim 25  wherein the molten metal pump has a passageway extending into the vortex well and there are a plurality of inert gas bubbles in said passageway and adjacent said vortex well there is a recess which is separated from said passageway by a plate with at least one aperture so that at least some of the inert gas from said bubbles enters the recess and then the vortex well as said bubble passes the aperture.  
     
     
         27 . The furnace of  claim 24  wherein the vortex well is a separate and replaceable block of refractory material.  
     
     
         28 . The process of  claim 24  wherein the vortex well is a refractory well block and there is a peripheral space between the cover and said refractory well block.  
     
     
         29 . The process of  claim 28  wherein metal chips mixed with volatile hydrocarbons are added to the vortex well and volatile hydrocarbons are removed through said space between said cover and said refractory well block.  
     
     
         30 . The process of  claim 24  wherein the molten metal recovered from the vortex well is removed to an intermediate well.  
     
     
         31 . The process of  claim 30  wherein molten metal from the intermediate well is re-circulated back to the main chamber.  
     
     
         32 . The process of  claim 24  wherein metal chips are tangentially added to the vortex well.  
     
     
         33 . The process of  claim 24  wherein the vortex well and the molten metal pump are contained in a well block and an adjoining end block which are converted by a projection from one of said blocks which engages a recess in said other block.  
     
     
         34 . The process of  claim 24  wherein the molten metal in the vortex well has a surface level and there is a sensor for measuring said molten metal surface level the cover are vertically displaceable to a position based on said molten metal surface level.  
     
     
         35 . The process of  claim 34  wherein the cover is fixed to a feed tube and the cover and feed tube are vertically replaceable together.  
     
     
         36 . The process of  claim 24  wherein the vortex well was upwardly extended walls and the containment means comprises said upwardly extended walls of the vortex well.  
     
     
         37 . The process of  claim 24  wherein the inert gas is selected from the group consisting of nitrogen and argon.  
     
     
         38 . The process of  claim 24  wherein there is a molten metal vortex in the vortex well.  
     
     
         39 . The process of  claim 38  wherein vortex contains a molten metal selected from the group consisting of aluminum, magnesium, zinc, copper, brass, and steel.  
     
     
         40 . In a process for melting metal in a furnace comprising the steps of: 
 providing a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    providing a containment means emplaced over the vortex well;    providing an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well;    wherein the improvement comprises providing and continuously or intermittently replenishing the inert gas atmosphere positioned in the vortex well beneath the cover.    
     
     
         41 . The process of  claim 40  wherein inert gas is recovered from the molten metal pump for use in the inert gas atmosphere.  
     
     
         42 . The process of  claim 41  wherein the molten metal pump has a passageway extending into the vortex well and there is at least one inert gas bubble in said passageway and adjacent said vortex well there is a recess which is connected to the said passageway by at least one aperture so that at least some of the inert gas from said bubbles enters the recess and then the vortex well as said bubble passes the aperture.  
     
     
         43 . A process of  claim 40  wherein the vortex well is in a refractory well block and there is a peripheral space between the cover and said refractory well block.  
     
     
         44 . The process of  claim 43  wherein metal chips mixed with volatile hydrocarbons are added to the vortex well and volatile hydrocarbons are removed through said space between said cover and said refractory well block.  
     
     
         45 . The process of  claim 40  wherein the vortex well has a bottom exit outlet and molten metal is removed to a circulation well from the main chamber before being removed to the vortex well, and said molten metal is then removed from said bottom exit outlet of said vortex well to an intermidiate well.  
     
     
         46 . A process for melting metal in a furnace comprising the steps of: 
 providing a main chamber containing molten metal and heating said molten metal in said main chamber;    providing a circulation well connected to the main chamber by a communication passageway and removing molten metal from the main chamber through said communication passageway into said circulation well;    providing a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    providing a containment means over the vortex well;    providing an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well, and the molten metal pump has a passageway extending into the vortex well, and forming in said molten metal pump at least one inert gas bubble in said passageway for removing molten metal from the circulation well to the vortex well, and providing adjacent said vortex well a recess which is connected to said passageway by a at least one aperture so that at least some of the inert gas from said bubble enters the recess and then the vortex well as said bubble passes the aperture.    
     
     
         47 . A metal-melting furnace comprising: 
 a main chamber;    a circulation well connected to the main chamber by a communication passageway;    a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    a containment means emplaced over the vortex well;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well, wherein the exit port is positioned at a vertical position which is higher than the entry port. an inert gas atmosphere positioned in the vortex well beneath the cover.    
     
     
         48 . A metal-melting furnace comprising: 
 a main chamber;    a circulation well connected to the main chamber by a communication passageway;    a vortex well having a periphery, a top and a bottom exit outlet for recovering molten metal therefrom;    a containment means emplaced over the vortex well;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well.    
     
     
         49 . A metal-melting furnace comprising: 
 a main chamber;    a circulation well containing molten metal having a surface level connected to the main chamber by a communication passageway;    a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    a cover emplaced over the vortex well;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well;    an inert gas atmosphere positioned in the vortex well beneath the cover;    means for sensing the surface level of the molten metal in the circulation well; and    means for vertically positioning the cover to a position selected based on the surface level of the molten metal.    
     
     
         50 . A metal-melting furnace comprising: 
 a main chamber;    a circulation well connected to the main chamber by a communication passageway;    a well block having, a vortex well, said vortex well having a periphery, top and an exit outlet for recovering molten metal therefrom;    a cover emplaced over the vortex well, wherein said cover has a periphery positioned inward spaced relation to the well block to form a peripheral gas release space between said cover and said well block;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well; and    an inert gas and volatile hydrocarbon gas atmosphere positioned in the vortex well beneath the cover wherein said atmosphere is releasable through said peripheral gas release space.    
     
     
         51 . A metal-melting furnace comprising: 
 a main chamber;    a circulation well connected to the main chamber by a communication passageway;    a vortex well containing a molten metal vortex having a surface, and said vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    a cover emplaced over the vortex well adjacent the surface of the molten metal vortex;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well; and    an inert gas atmosphere positioned in the vortex well beneath the cover.    
     
     
         52 . A metal-melting furnace comprising: 
 a main chamber;    a circulation well connected to the main chamber by a communication passageway;    a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom;    a containment means emplaced over the vortex well;    a feed tube extending through said containment means to enable metal chips to be tangentially added to the vortex well adjacent the periphery of said vortex well;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well; and    an inert gas atmosphere positioned in the vortex well beneath the cover.    
     
     
         53 . A metal-melting furnace comprising: 
 a main chamber    a circulation well connected to the main chamber by a communication passageway;    a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom wherein said vortex well is positioned in a vortex well block;    a containment means emplaced over the vortex well;    an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well;    an inert gas atmosphere positioned in the vortex well beneath the containment means; and    An end block positioned in adjoining relation to the vortex well block wherein said blocks are connected by a projection extending from one of said blocks which engages a recess in said other block, and said circulation well is contained in said adjoining blocks.