Induction powered ladle bottom nozzle

Abstract

A ladle ( 2 ) or other container for molten metal ( 5 ) is provided with an outlet nozzle ( 4 ) that allows a stream of molten metal to flow by heating the nozzle ( 4 ) to the melting temperature of the metal ( 5 ). The nozzle ( 4 ) is, for example, tubular and made of AI2O3 or SiO2 and is surrounded by a graphite tube ( 8 ) in thermal contact with the nozzle ( 4 ). The nozzle ( 4 ) is heated by heating the surrounding graphite tube (S) inductively. Once the temperature of the nozzle ( 4 ) exceeds the liquidus temperature of the metal ( 5 ) in the ladle ( 2 ), the metal ( 5 ) will flow out of the ladle ( 2 ) through the nozzle ( 4 ).

1 . An outlet for a ladle comprising a nozzle configured to be heated and allow metal to flow therethrough when heated and to block flow when not heated. 
   
   
       2 . An outlet for a ladle according to  claim 1  further comprising a graphite susceptor in thermal contact with the nozzle, and an induction coil for heating the susceptor. 
   
   
       3 . An outlet for a ladle according to  claim 2  in combination with a container for holding molten metal. 
   
   
       4 . A container for holding molten metal comprising an outlet nozzle and a cooled induction coil for heating said nozzle when electrical power is applied to said coil and for cooling said nozzle when said electrical power is reduced or terminated. 
   
   
       5 . A container according to  claim 4  wherein said nozzle comprises graphite. 
   
   
       6 . A container according to  claim 4  further comprising a graphite susceptor in thermal contact with said nozzle. 
   
   
       7 . A method for controlling the discharge of molten metal from a container comprising providing said container with an outlet nozzle, providing means for heating said outlet nozzle, and controlling the temperature of said outlet nozzle. 
   
   
       8 . A method according to  claim 7  further comprising applying a vacuum to said container.