System for gas purification in an induction vacuum furnace and method of making same

Abstract

A system and method for removing impurities in an induction furnace cooling system is disclosed. An induction furnace for heating a workpiece includes a chamber, an induction coil positioned in the chamber to provide for heating of the workpiece when a current is provided to the induction coil, and a cooling system fluidly coupled to an interior volume of the chamber, the cooling system including a heat exchanger, a blower fluidly coupled to the heat exchanger and configured to cause a gas to flow through the heat exchanger, and a filter assembly comprising a filtering device, the filter assembly fluidly coupled to the blower and configured to remove impurities from the gas flowing through the cooling system.

What is claimed is: 
     
         1 . An induction furnace for heating a workpiece, the induction furnace comprising:
 a chamber;   an induction coil positioned in the chamber to provide for heating of the workpiece when a current is provided to the induction coil; and   a cooling system fluidly coupled to an interior volume of the chamber, the cooling system comprising:
 a heat exchanger; 
 a blower fluidly coupled to the heat exchanger and configured to cause a gas to flow through the heat exchanger; and 
 a filter assembly comprising a filtering device, the filter assembly fluidly coupled to the blower and configured to remove impurities from the gas flowing through the cooling system. 
   
     
     
         2 . The induction furnace of  claim 1  wherein the filter assembly comprises a housing; and
 wherein the filtering device comprises a filter material positioned within the housing and configured to remove impurities from the gas flowing through the cooling system. 
 
     
     
         3 . The induction furnace of  claim 2  wherein the filter material comprise one of metallic wool, charcoal, or metallic mesh, with the filter material configured to filter out at least one of particulate matter, organics, oxygen, or another desired substance. 
     
     
         4 . The induction furnace of  claim 1  wherein the filter assembly is positioned externally to an interior volume of the chamber. 
     
     
         5 . The induction furnace of  claim 1  wherein the filter assembly is positioned just within an interior volume of the chamber. 
     
     
         6 . The induction furnace of  claim 1  wherein the heat exchanger and the blower are positioned externally to an interior volume of the chamber. 
     
     
         7 . The induction furnace of  claim 1  further comprising a vacuum pump configured to create a vacuum within the chamber. 
     
     
         8 . The induction furnace of  claim 1  further comprising:
 an insulation cylinder positioned within the chamber, the insulation cylinder including a bottom cover that is selectively movable between an open position and a closed position, wherein the closed position is configured to seal an interior volume of the insulation cylinder; and 
 a susceptor positioned within the insulation cylinder, the susceptor being inductively heated by the induction coil when a current is provided to the induction coil. 
 
     
     
         9 . The induction furnace of  claim 8  further comprising:
 a first member coupled to the bottom cover of the insulation cylinder and extending through a wall of the chamber; 
 a linear actuator coupled to the first member, the linear actuator configured to selectively translate the first member to move the bottom cover of the insulation cylinder between the open and closed positions; and 
 a bellows system encircling a portion of the first member and configured to hermetically seal an interior volume of the chamber from an environment volume external to the chamber; 
 wherein the linear actuator is coupled to the wall of the chamber external to an interior volume of the chamber. 
 
     
     
         10 . The induction furnace of  claim 1  further comprising a cooling manifold fluidly coupled to the cooling system and constructed to surround the bottom cover when the bottom cover is positioned in the open position, the cooling manifold comprising a plurality of gas ports spaced apart so as to be positioned about the bottom cover;
 wherein cooling gas received from an external source is passed through the cooling manifold and exits the plurality of gas ports so as to provide a distributed and uniform gas flow across a workpiece supported by the bottom cover. 
 
     
     
         11 . An induction furnace for cooling a workpiece, the induction furnace comprising:
 a chamber;   a heating zone located within the chamber for heating the workpiece;   a cooling zone located within the chamber for cooling the workpiece; and   a cooling system configured to cool the chamber after the workpiece has been heated, the cooling system comprising:
 a heat exchanger configured to draw hot gas from the chamber; 
 a blower configured to blow cooled gas that has passed through the heat exchanger into the cooling zone; and 
 a filter assembly comprising a filtering device, the filter assembly configured to remove impurities from the gas flowing through the cooling system. 
   
     
     
         12 . The induction furnace of  claim 11  wherein the cooling system is positioned externally to an interior volume of the chamber or within an interior volume of the chamber, adjacent an exterior wall of the chamber. 
     
     
         13 . The induction furnace of  claim 12  wherein the filtering device comprises one of metallic wool, charcoal, or metallic mesh, with the filtering device configured to filter out at least one of particulate matter, organics, oxygen, or another desired substance. 
     
     
         14 . The induction furnace of  claim 11  wherein the filter assembly is positioned upstream from the blower. 
     
     
         15 . The induction furnace of  claim 14  wherein the filter assembly is further positioned downstream from the heat exchanger. 
     
     
         16 . The induction furnace of  claim 11  further comprising a susceptor positioned in the chamber and configured to be inductively heated by an induction coil when a current is provided to the induction coil, wherein an interior volume of the susceptor defines the heating zone and the cooling zone is positioned outside of the interior volume of the susceptor. 
     
     
         17 . The induction furnace of  claim 16  further comprising:
 a support system coupled to a base of the susceptor, the support system extending through the wall of the chamber; 
 a linear actuator coupled to the support system and configured to selectively translate the support system to move the base of the susceptor to translate a workpiece tray supported by the base of the susceptor between the heating zone and the cooling zone; and 
 a bellows system configured to surround a portion of the support system to hermetically seal the heating and cooling zones from an environment volume external to the chamber. 
 
     
     
         18 . The induction furnace of  claim 11  further comprising a cooling manifold connected to the blower so as to receive cooled gas therefrom, the cooling manifold constructed to encircle the cooling zone and provide a distributed and controlled gasflow across the workpiece. 
     
     
         19 . A method of making an induction furnace comprising:
 providing a chamber that defines an interior volume capable of receiving a workpiece therein;   positioning an induction coil within the chamber to provide for heating of the workpiece when a current is provided to the induction coil;   fluidly coupling a heat exchanger to the interior volume of the chamber;   fluidly coupling a blower to the interior volume of the chamber;   fluidly coupling a filter to the interior volume of the chamber, to the heat exchanger, and to the blower; and   configuring the filter to remove impurities from the interior volume of the chamber.   
     
     
         20 . The method of  claim 19  further comprising coupling the heat exchanger, the blower, and the filter to the chamber externally to the interior volume of the chamber.