Scrap melter and impeller therefore

Abstract

A device for submerging scrap metal includes: (a) a drive source, (b) a drive shaft having a first end and a second end, the first end being connected to the drive source, and (d) an impeller connected to the second end of the drive shaft, the impeller preferably having two or more outwardly-extending blades. Preferably, each of the blades has a portion that directs molten metal at least partially downward. The impeller design leads to lower operating speeds, lower vibration, longer component life and less maintenance. Additionally, the impeller preferably has a connective portion. The connective portion is used to connect the impeller to the shaft and preferably comprises a nonthreaded, tapered bore extending through the impeller.

What is claimed is:  
     
         1 . A device for generating a downward stream of molten metal, the device including: 
 (a) a drive source;    (b) a drive shaft having a first end and a second end, the first end connected to the drive source; and    (c) an impeller connected to the second end of the drive shaft, the impeller having two or more outwardly extending blades, at least one blade including a portion that directs molten metal at least partially downward.    
     
     
         2 . The device of  claim 1  wherein the impeller has four blades.  
     
     
         3 . The device of  claim 1  wherein a connective portion is formed in the impeller, the connective portion connecting the impeller to the drive shaft, the connective portion comprising a tapered, nonthreaded bore extending through the impeller.  
     
     
         4 . The device of  claim 3  which further includes a nut and wherein the second end of the drive shaft has a threaded section that is positioned beneath the impeller; the nut being threaded onto the threaded section to connect the impeller to the drive shaft.  
     
     
         5 . The device of  claim 1  wherein the portion that directs molten metal at least partially downward is an angled surface.  
     
     
         6 . The device of  claim 1  wherein each blade includes a portion that directs molten metal at least partially downward.  
     
     
         7 . The device of  claim 1  wherein the impeller has an overall length of at least 28″.  
     
     
         8 . The device of  claim 2  wherein the impeller has an overall length of at least 28″ and an overall width of at least 28″.  
     
     
         9 . The device of  claim 1  wherein each blade has a height of between 6″ and 7″.  
     
     
         10 . The device of  claim 5  wherein the angled surface is formed at a 45° angle.  
     
     
         11 . A device for melting scrap metal, the device comprising: 
 (a) a vessel containing molten metal; and    (b) a scrap melter positioned in the vessel, the scrap melter comprising: 
 (i) a drive source;  
 (ii) a drive shaft having an first end and a second end, the first end being connected to the drive source; and  
 (iii) an impeller connected to the second end of the drive shaft, the impeller having two or more outwardly extending blades, at least one of the blades including a portion that directs molten metal at least partially downward.  
   
     
     
         12 . The device of  claim 11  that further includes a circulation pump positioned in the vessel.  
     
     
         13 . The device of  claim 11  wherein the portion that directs molten metal at least partially downward is an angled surface.  
     
     
         14 . The device of  claim 13  wherein the angled surface is formed at a 45° angle.  
     
     
         15 . The device of  claim 11  wherein the impeller has four blades.  
     
     
         16 . The device of  claim 15  wherein the impeller further includes a hub and each blade extends outward from the hub by at least 10″.  
     
     
         17 . The device of  claim 11  wherein each blade has a height between 6″ and 7″.  
     
     
         18 . The device of  claim 11  wherein the vessel has two compartments.  
     
     
         19 . An impeller for use in a molten metal bath, the impeller comprising: 
 (d) means for connecting the impeller to a shaft, and    (e) means for generating a flow of molten metal.    
     
     
         20 . The impeller of  claim 19  wherein the means for connecting is a tapered, nonthreaded bore extending through the impeller.  
     
     
         21 . The impeller of  claim 19  wherein the means for generating a flow of molten metal is two or more blades formed on the impeller and extending outwardly from a hub, at least one of the blades having a portion for directing molten metal at least partially downward.  
     
     
         22 . The impeller of  claim 21  wherein there are four blades and the impeller further includes a hub.  
     
     
         23 . The impeller of  claim 21  wherein at least one of the portions for directing molten metal at least partially downward is an angled surface.  
     
     
         24 . The impeller of  claim 22  wherein each of the blades extends outward from the hub by at least ten inches.  
     
     
         26 . A device for generating a downward stream of molten metal, the device including: 
 (f) a drive source;    (g) a drive shaft having a first end and a second end, the first end connected to the drive source; and    (h) an impeller connected to the second end of the drive shaft, the impeller having two or more outwardly extending blades, at least one blade including a vertical face that directs molten metal at outward from the impeller.    
     
     
         27 . The device of  claim 26  wherein the impeller has four blades.  
     
     
         28 . The impeller of  claim 27  wherein the impeller is in the shape of a cross.  
     
     
         29 . The device of  claim 26  wherein the vertical face of each blade is at least 6 inches in height.  
     
     
         30 . The device of  claim 26  wherein the vertical face of each blade is more than 4 inches in height.  
     
     
         38 . An open impeller for circulating molten metal in a molten metal bath, the impeller comprising: 
 a hub;    three or more blades extending outwardly from said hub, there being spaces between the blades, wherein at least one of said three or more blades includes an angled surface for directing molten metal at least partially in a downward direction, and wherein at least one of said three or more blades includes a vertical surface for directing molten metal at least partially in a radially outward direction, the hub including a non-threaded tapered bore for receiving an end of a drive shaft.    
     
     
         39 . The impeller of  claim 38  wherein the impeller includes four blades formed in substantially a cross shape.  
     
     
         40 . The impeller of  claim 38  wherein each of the three or more blades includes an angled surface and a vertical surface.  
     
     
         41 . The impeller of  claim 38  wherein the angled surface is formed at a 45° angle.  
     
     
         42 . The impeller of  claim 38  wherein each of the three or more blades extends outward from said hub by at least 10″.  
     
     
         43 . A device for generating a downward stream of molten metal, the device comprising: 
 a drive source;    a drive shaft having a first end connected to the drive source and a second end; and    the impeller of  claim 38  connected to the second end of the drive shaft.    
     
     
         44 . A molten metal mixing device, the device comprising: 
 a drive source;    a drive shaft having a first end connected to the drive source and a second end;    an impeller for mixing molten metal, the impeller comprising two or more blades and a bore for receiving the second end of the drive shaft; and    a fastener to secure the second end to the impeller, the fastener connected to the second end of the drive shaft and positioned beneath the impeller.    
     
     
         47 . A device for generating a downward stream of molten metal, the device comprising: 
 a drive source;    a drive shaft having a first end connected to the drive source and a second end; and an open impeller having a plurality of outward extending blades wherein each of the plurality of blades has a portion that directs molten metal at least partially downward, and each of the blades has a height and a width, the height being less than four times the width, and wherein the impeller further includes a tapered, non-threaded bore extending therethough.    
     
     
         48 . The device of  claim 47  wherein the portion is an angled surface.  
     
     
         49 . The device of  claim 47  that further includes a connective portion in the impeller for attaching the impeller to the drive shaft, the connective portion comprising a tapered, non-threaded bore.  
     
     
         50 . The device of  claim 47  wherein the width is greater than the height.  
     
     
         51 . A device for generating a downward stream of molten metal, the device comprising: 
 a drive source;    a draft shaft having a first end connected to the drive source and a second end; and    an open impeller means for directing molten metal at least partially downward.    
     
     
         52 . The device of  claim 50  wherein the impeller means includes a plurality of blades wherein each of the blades comprises an angled surface and includes a height and width, the height being less than four times the width.  
     
     
         57 . The impeller of  claim 38  wherein the impeller is comprised of graphite.  
     
     
         58 . The impeller of  claim 38  wherein each of the three or more blades includes an angled surface.  
     
     
         59 . The molten metal mixing device of  claim 44  that is a scrap melter.  
     
     
         60 . The molten metal mixing device of  claim 44  wherein the drive shaft and the impeller are comprised of graphite.