Electric induction impeder

Abstract

An impeder for use in an electric induction welding process is provided. Optionally the impeder does not require internal forced cooling. In embodiments using internal forced cooling a high efficiency cooling system is provided.

1 . An impeder for controlling the magnetic field path in an electric induction welding process, the impeder comprising: 
 a plurality of magnetically conductive, high Curie temperature solid wires assembled in a bundle, each of the plurality of wires electrically isolated from each other; and    a high temperature enclosure surrounding the plurality of wires.    
   
   
       2 . The impeder of  claim 1  wherein at least one of the magnetically conductive, high Curie temperature solid wires comprise permendur.  
   
   
       3 . The impeder of  claim 1  wherein at least a part of the high temperature enclosure is formed from sialon.  
   
   
       4 . The impeder of  claim 1  wherein at least part of the high temperature enclosure comprises polyaramid polyparaphenylene terephthalamide.  
   
   
       5 . The impeder of  claim 1  further comprising: 
 at least one passage formed through the plurality of wires for flow of a cooling medium through the at least one passage to cool the plurality of wires;    at least one inlet port disposed in the enclosure for injecting the cooling medium into the at least one passage; and    at least one outlet port disposed in the enclosure for discharging the cooling medium from the at least one passage.    
   
   
       6 . The impeder of  claim 5  further comprising a venturi element at the inlet of at least one of the at least one inlet port.  
   
   
       7 . An impeder for controlling the magnetic field path in an electric induction welding process, the impeder comprising: 
 a rolled sheet of magnetically conductive, high Curie temperature material, the rolled sheet having adjacent surfaces electrically isolated from each other; and    a high temperature enclosure surrounding the rolled sheet.    
   
   
       8 . The impeder of  claim 7  further comprising: 
 at least one passage formed through the rolled sheet for flow of a cooling medium through the at least one passage to cool the rolled sheet;    at least one inlet port disposed in the enclosure for injecting the cooling medium into the at least one passage; and    at least one outlet port disposed in the enclosure for discharging the cooling medium from the at least one passage.    
   
   
       9 . An impeder for controlling the magnetic field path in an electric induction welding process, the impeder comprising: 
 a magnetic material having at least one entry passage formed therethrough for entry flow of a cooling medium; and    a high temperature enclosure surrounding the magnetic material, the magnetic material spaced apart from the interior wall of the enclosure to form at least one exit passage for exit flow of the cooling medium, the enclosure having at least one inlet port and at least one outlet port for injecting the cooling medium into the at least one entry passage and discharging the cooling medium from the at least one exit passage, respectively.    
   
   
       10 . The impeder of  claim 9  wherein the magnetic material comprises a ferrite material.  
   
   
       11 . The impeder of  claim 9  wherein the magnetic material comprises a plurality of magnetically conductive, high Curie temperature solid wires assembled in a bundle, each of the plurality of wires electrically isolated from each other.  
   
   
       12 . The impeder of  claim 9  wherein the magnetic material comprises a rolled sheet of magnetically conductive, high Curie temperature material having adjacent surfaces of the rolled sheet electrically isolated from each other.  
   
   
       13 . The impeder of  claim 9  further comprising means for directing the cooling medium from the at least one outlet port to flush excess mill coolant from the workpiece being welded in the electric induction welding process.  
   
   
       14 . The impeder of  claim 9  further comprising a laminar flow reducing textured surface on the walls of the magnetic material forming a boundary for the at least one entry and exit passages.  
   
   
       15 . An impeder for controlling the magnetic field path in an electric induction welding process, the impeder comprising: 
 a magnetic material;    a high temperature enclosure surrounding the magnetic material, the magnetic material spaced apart from the interior wall of the enclosure to form a coolant passage around the exterior of the magnetic material, the enclosure having at least one inlet port at the first end of the enclosure and at least one outlet port at the end of the enclosure opposing the first end, the at least one inlet and outlet ports in communication with the coolant passage for injecting a cooling medium into the at least inlet port and discharging the cooling medium from the at least one outlet port, respectively.    
   
   
       16 . The impeder of  claim 15  wherein the magnetic material comprises a ferrite material.  
   
   
       17 . The impeder of  claim 15  wherein the magnetic material comprises a plurality of magnetically conductive, high Curie temperature solid wires are assembled in a bundle, each of the plurality of wires electrically isolated from each other.  
   
   
       18 . The impeder of  claim 15  wherein the magnetic material comprises a rolled sheet of magnetically conductive, high Curie temperature material having adjacent surfaces of the rolled sheet electrically isolated from each other.  
   
   
       19 . A method of electric induction welding to form a product from a stock material, the method comprising the steps of: 
 forming an impeder element from a ferrite, a plurality of electrically insulated, magnetically conductive, high Curie temperature solid wires, or a rolled sheet of magnetically conductive, high Curie Temperature material having adjacent surfaces of the rolled sheet electrically isolated from each other;    surrounding the impeder element with a high temperature enclosure to form an impeder;    placing the impeder in the vicinity of the weld area for the stock material; and    applying a magnetic field to the weld area to form the product.    
   
   
       20 . The method of  claim 19  further comprising the step of forming a coolant passage between the inner wall of the high temperature enclosure and the outer boundary of the impeder element in communication with at least one inlet port and at least one outlet port in the high temperature enclosure.  
   
   
       21 . The method of  claim 19  further comprising the step of forming at least one coolant passage through the impeder element in communication with at least one inlet port and at least one outlet port in the high temperature enclosure.  
   
   
       22 . The method of  claim 21  further comprising the step of forming a second coolant passage in a space between the inner wall of the high temperature enclosure and the outer boundary of the impeder element whereby coolant flowing in the second coolant passage flows substantially in the opposite direction of coolant flow in the at least one coolant passage from the at least one inlet port to the at least one outlet port.