Electric Induction Heating and Stirring of an Electrically Conductive Material in a Containment Vessel

Abstract

Apparatus and method are provided for electric induction heating and/or stirring of a molten electrically conductive composition in a containment vessel with the apparatus being removably insertable in the molten composition. An induction coil embedded in refractory or a coating is submerged in the composition and used to heat and/or stir the molten composition either externally or internally to the refractory or coating.

1 . A submersible channeless heating and stirring apparatus for heating and stirring an electrically conductive composition in a containment vessel by submersion of the submersible channeless heating and stirring apparatus into the electrically conductive composition to a coil submersion level, the apparatus comprising:
 an inductor assembly comprising:
 one or more solenoidal induction coils; and 
 a coating material applied to an exterior of the one or more solenoidal induction coils at least below the coil submersion level; and 
 a pair of coil terminals for connecting each one of the one or more solenoidal induction coils to at least one alternating current power source for an electromagnetic heating and stirring of the electrically conductive composition surrounding the one or more solenoidal induction coils when the inductor assembly is at the coil submersion level; 
 and 
   a transport apparatus for engaging the inductor assembly, the transport apparatus comprising at least a means for lowering the inductor assembly into the electrically conductive composition up to the coil submersion level.   
     
     
         2 . The submersible channeless heating and stirring apparatus of  claim 1  wherein the thickness of the coating material prevents short circuiting of the one or more solenoidal induction coils and allows Joule heating from a current flow through the one or more solenoidal induction coils to heat by conduction the electrically conductive composition surrounding the one or more solenoidal induction coils when the inductor assembly is at the coil submersion level and the electrically conductive composition is a quasi-infinite heat sink. 
     
     
         3 . The submersible channeless heating and stirring apparatus of  claim 2  wherein the one or more solenoidal induction coils are formed from a non-metallic material. 
     
     
         4 . The submersible channeless heating and stirring apparatus of  claim 1  wherein a low load power factor is reflected to the at least one alternating current source to establish a high electromagnetic stirring to a low electromagnetic heating ratio of the electrically conductive composition. 
     
     
         5 . The submersible channeless heating and stirring apparatus of  claim 1  wherein the one or more solenoidal induction coils comprises a multi-section solenoidal induction coil and the at least one alternating current source comprises a separate phase-shifted output power source connected to each of the sections of the multi-section solenoidal induction coil whereby a unidirectional electromagnetically induced flow of the electrically conductive material is established within the multi-section solenoidal induction coil. 
     
     
         6 . The submersible channeless heating and stirring apparatus of  claim 1  further comprising one or more cooling passages formed in the one or more solenoidal induction coils or the coating material. 
     
     
         7 . The submersible channeless heating and stirring apparatus of  claim 1  wherein the transport apparatus further comprises a lock and release mechanism for respectively engaging or disengaging the inductor assembly when the inductor assembly is lowered into the electrically conductive composition. 
     
     
         8 . The submersible channeless heating and stirring apparatus of  claim 7  wherein the transport apparatus further comprises an inductor assembly translation or rotation subassembly for respectively translating or rotating an engaged inductor assembly when the inductor assembly is lowered into the electrically conductive composition to redirect the electromagnetic stirring of the electrically conductive composition. 
     
     
         9 . The submersible channeless heating and stirring apparatus of  claim 1  further comprising at least one fluid injection passage within the coating material, the at least one fluid injection passage having a fluid exit opening in the coating material below the coil submersion level and a fluid supply opening in the coating material above the coil submersion level so that when the submersible channeless heating and stirring apparatus is lowered into the electrically conductive composition, a fluid medium supplied to the fluid supply opening is injected into the electrically conductive composition through the fluid exit opening. 
     
     
         10 . The submersible channeless heating and stirring apparatus of  claim 1  further comprising:
 at least one resistive heating element embedded in the coating material; and 
 a means of supplying at least one source of electric power to the at least one resistive heating element when the submersible channeless heating and stirring apparatus is submerged in the electrically conductive composition. 
 
     
     
         11 . The submersible channeless heating and stirring apparatus of  claim 1  wherein the containment vessel comprises a process vessel for a coating of a workpiece passing through the electrically conductive composition in the containment vessel or for an extraction of a metal from the electrically conductive composition by an electrolysis process. 
     
     
         12 . A submersible channeless heating and stirring apparatus for heating and stirring an electrically conductive composition in a containment vessel by submersion of the submersible channeless heating and stirring apparatus into the electrically conductive composition to a coil submersion level, the apparatus comprising:
 an inductor assembly comprising:
 one or more solenoidal induction coils; and 
 a coating material applied to an exterior of the one or more solenoidal induction coils at least below the coil submersion level, the coating material having a thickness for preventing a short circuit of the one or more solenoidal induction coils and allowing the transfer of Joule heating to the electrically conductive composition when a current flows in the one or more solenoidal induction coils and the inductor assembly is at the coil submersion level; and 
 a pair of coil terminals for connecting each one of the one or more solenoidal induction coils to at least one alternating current power source for an electromagnetic heating and stirring of the electrically conductive composition surrounding the one or more solenoidal induction coils when the inductor assembly is at the coil submersion level; 
 and 
   a transport apparatus for engaging the inductor assembly, the transport apparatus comprising at least a means for lowering the inductor assembly into the electrically conductive composition up to the coil submersion level.   
     
     
         13 . The submersible channeless heating and stirring apparatus of  claim 12  wherein the one or more solenoidal induction coils are formed from a non-metallic material. 
     
     
         14 . The submersible channeless heating and stirring apparatus of  claim 12  wherein a low load power factor is reflected to the at least one alternating current source to establish a high electromagnetic stirring to a low electromagnetic heating ratio of the electrically conductive composition. 
     
     
         15 . The submersible channeless heating and stirring apparatus of  claim 12  wherein the one or more solenoidal induction coils comprises a multi-section solenoidal induction coil and the at least one alternating current source comprises a separate phase-shifted output power source connected to each of the sections of the multi-section solenoidal induction coil whereby a unidirectional electromagnetically induced flow of the electrically conductive material is established within the multi-section solenoidal induction coil. 
     
     
         16 . A method of channeless electric induction heating and stirring of an electrically conductive composition in a containment vessel, the method comprising:
 submerging an inductor assembly with a transport apparatus into the electrically conductive composition to a coil submersion level, the inductor assembly comprising:
 one or more solenoidal induction coils; 
 a coating material applied to an exterior of the one or more solenoidal induction coils at least below the coil submersion level; and 
 a pair of coil terminals for connecting each one of the one or more solenoidal induction coils to at least one alternating current power source; and 
 connecting each of the pair of coil terminals to the at least one alternating current power source for an electromagnetic heating and stirring of the electrically conductive composition surrounding the one or more solenoidal induction coils at the coil submersion level. 
   
     
     
         17 . The method of  claim 16  further comprising heating the electrically conductive composition by conduction of Joule heating from a current flow through the one or more solenoidal induction coils. 
     
     
         18 . The method of  claim 16  further comprising changing the output phasing of the at least one alternating current power source to redirect the electromagnetic stirring of the electrically conductive composition. 
     
     
         19 . The method of  claim 16  further comprising moving the inductor assembly in one or more directions to redirect the electromagnetic stirring of the electrically conductive composition. 
     
     
         20 . The method of  claim 16  further comprising artificially reflecting a low load power factor to the at least one alternating current source to alter the ratio of the electromagnetic heating to the electromagnetic stirring.