Pumping

Abstract

A pump and a method of moving molten metal is provided in which a tube open at one end and closed at the other end cooperates with a secondary tube received within it, open at both ends, to pump metal from the open end of the tube down a space between the tube and secondary tube to the closed end of the tube and then return the metal up the centre of the secondary tube. A simpler way of providing circulation of molten metal is provided.

1 . A pump for molten metal, the pump comprising a tube, the tube being open at one end and closed at the other end, one or more side walls extending between the open and closed ends, an electrical conductor being wrapped around the tube, a secondary tube being provided within the tube, the secondary tube having a through aperture extending from a first end to a second end and being spaced from at least a part of the side wall of the tube and at least a part of the closed end of the tube.  
   
   
       2 . A pump for molten metal, the pump comprising a tube, the tube being open at one end and closed at the other end, one or more side walls extending between the open and closed ends, an electrical conductor being wrapped around the tube.  
   
   
       3 . A pump according to  claim 2  in which the internal profile of the tube is configured to promote flow into the tube at the periphery of the tube and/or to promote flow out of the tube at the centre of the tube, preferably at the same time.  
   
   
       4 . A pump according to  claim 2  in which a secondary tube is provided within the tube, the secondary tube has a through aperture extending from a first end to a second end and the secondary tube is spaced from at least a part of the side wall of the tube and at least a part of the closed end of the tube.  
   
   
       5 . A pump according to  claim 2  in which the tube is of constant cross-section between the open end and the start of the closed end.  
   
   
       6 . A pump according to  claim 2  in which the closed end of the tube is formed by a tapering of the side walls and/or cross-sectional shape of the tube.  
   
   
       7 . A pump according to  claim 2  in which the closed end of the tube is dome shaped.  
   
   
       8 . A pump according to  claim 2  in which the closed end of the tube is initially dome inwards and has a middle portion which extends back towards the open end of the tube.  
   
   
       9 . A pump according to  claim 2  in which the secondary tube extends along the same axis as the tube.  
   
   
       10 . A pump according to  claim 2  in which the secondary tube is of constant cross-section between its open ends.  
   
   
       11 . A pump according to  claim 2  in which both the open end of the tube and the first open end of the secondary tube are in fluid connection with the vessel through a single opening in the vessel.  
   
   
       12 . A pump according to  claim 2  in which the open end of the tube has a cross-sectional area which is between 3 and 5 times the cross-sectional area of the first and/or second open ends of the secondary tube.  
   
   
       13 . A pump according to  claim 2  in which the through aperture of the secondary tube is of consistent cross-section throughout.  
   
   
       14 . A pump according to  claim 2  in which the secondary tube is spaced from the tube by one or more spanning portions between the outside of the secondary tube and the inside of the tube.  
   
   
       15 . A pump according to  claim 14  in which the spanning portions have an outer surface at least a part of which has a profile configured to match the internal profile of at least a part of the tube. The part may have a profile configured to match the side wall of the tube.  
   
   
       16 . A pump according to  claim 14  in which the spanning portions are in the form of pillars provided on the secondary tube.  
   
   
       17 . A pump according to  claim 2  in which the spacing defines one or more passageways between the inside of the tube and the outside of the secondary tube.  
   
   
       18 . A pump according to  claim 2  in which the secondary tube is spaced from the tube equally in all radial directions.  
   
   
       19 . A pump according to  claim 2  in which the second end of the secondary tube has a spacing of between 5 cm and 30 cm relative to the closed end of the tube.  
   
   
       20 . A method of moving molten metal, the method comprising: 
 providing a pump in fluid communication with a volume of molten metal, the pump comprising a tube, the tube being open at one end to the molten metal and closed at the other end, one or more side walls extending between the open and closed ends of the tube;    passing an electric current through a conductor wrapped around the tube, the electromagnetic field produced causing molten metal to flow into the tube at the periphery of the tube and to flow out of the tube at the centre of the tube.    
   
   
       21 . A method according to  claim 20  in which the internal profile of the tube is configured to promote the flow into the tube at the periphery of the tube and/or to promote the flow out of the tube at the centre of the tube.  
   
   
       22 . A method according to  claim 20  in which the method includes providing a secondary tube within the tube, the secondary tube separates the flow into and flow out of the tube and/or assists in the promotion of the stated flow.  
   
   
       23 . A method according to  claim 20  in which the molten metal flows into the tube along one or more spaces defined between the inside of the tube and outside of the inner tube and/or the molten metal flows out of the tube through the secondary tube.  
   
   
       24 . A method according to  claim 20  in which the molten metal under goes a change in direction at or near the closed end of the tube.  
   
   
       25 . A method according to  claim 20  in which the flow velocity within the secondary tube is higher than the flow velocity in the passageway between the tube and secondary tube.