Furnace for sintering printed objects

Abstract

A furnace system for printing an object using additive manufacturing. The furnace system may include a furnace chamber; an outlet fluidly coupled to the furnace chamber for removal of an exhaust gas from the furnace chamber; a conduit fluidly coupled to the outlet; an oxygen injector fluidly coupled to the conduit; an isolation system fluidly coupled to the conduit between the furnace chamber and the oxygen injector; and a catalyst enclosure comprising an oxidizing catalyst.

What is claimed is: 
     
         1 . A furnace system, comprising:
 a furnace chamber defining an interior region, wherein the furnace chamber is configured to maintain an atmosphere substantially free of oxygen within the interior region;   an outlet fluidly coupled to the furnace chamber for removal of an exhaust gas from the furnace chamber;   a conduit fluidly coupled to the outlet;   an oxygen injector fluidly coupled to the conduit, wherein the oxidizing injector is positioned downstream of the furnace chamber and is configured to introduce an oxidizing gas into the exhaust gas;   an isolation system fluidly coupled to the conduit between the furnace chamber and the oxygen injector, wherein the isolation system is configured to prevent a backflow of the oxidizing gas into the furnace chamber; and   a catalyst enclosure comprising an oxidizing catalyst, wherein the catalyst enclosure is configured to receive a mixture of the exhaust gas and the oxidizing gas.   
     
     
         2 . The furnace system of  claim 1 , wherein the isolation system comprises a pump configured to direct the exhaust gas through the isolation system and towards the catalyst enclosure, wherein the pump is at least one of a vacuum pump, a lobe pump, a diaphragm pump, a piston pump, or a venturi pump. 
     
     
         3 . The furnace system of  claim 2 , further comprising:
 a demister positioned between the vacuum pump and the catalyst enclosure, wherein the demister is configured to remove at least a portion of fluid present in the exhaust gas directed towards the catalyst enclosure, and wherein the demister is fluidly connected to the vacuum pump such that the removed fluid is drained back to the vacuum pump.   
     
     
         4 . The furnace system of  claim 1 , wherein the isolation system comprises a check valve configured to prevent the backflow of the oxidizing gas into the furnace chamber. 
     
     
         5 . The furnace system of  claim 1 , wherein the isolation system comprises a proportional valve configured to prevent the backflow of the oxidizing gas into the furnace chamber, wherein the proportional valve is at least one of a proportional butterfly valve or a proportional solenoid valve. 
     
     
         6 . The furnace system of  claim 1 , wherein the isolation system comprises a porous plug configured to prevent the backflow of the oxidizing gas into the furnace chamber. 
     
     
         7 . The furnace system of  claim 1 , further comprising a heater operably coupled to the conduit, and wherein the conduit is configured to be adjustably heated. 
     
     
         8 . The furnace system of  claim 7 , wherein the isolation system comprises a liquid bubbler configured to prevent the backflow of the oxidizing gas into the furnace chamber and to collect at least a portion of a component present in the exhaust gas. 
     
     
         9 . The furnace system of  claim 8 , wherein the liquid bubbler comprises a connecting conduit with a first end and a second end, a first chamber fluidly connected to the conduit and the first end of the connecting conduit, and a second chamber fluidly connected to an outlet conduit and the second end of the connecting conduit,
 wherein the first end of the connecting conduit is located within the first chamber, and the second end of the connecting conduit is located within the second chamber, and the second chamber is at least partially filled with a liquid such that a top surface of the liquid is above the second end of the connecting conduit, and   wherein the liquid bubbler is configured to sequentially receive the exhaust gas through the first chamber, the connecting conduit, the second chamber, and the outlet conduit.   
     
     
         10 . A furnace system, comprising:
 a furnace chamber defining an interior region, wherein the furnace chamber is configured to maintain an atmosphere substantially free of oxygen within the interior region;   an outlet fluidly coupled to the furnace chamber for removal of an exhaust gas from the furnace chamber;   a binder trap system fluidly coupled to the outlet;   an isolation system fluidly coupled to the binder trap system, wherein the isolation system is positioned downstream of the binder trap system and is configured to prevent a backflow of an oxidizing gas into the furnace chamber;   a catalyst enclosure comprising an oxidizing catalyst, wherein the catalyst enclosure is positioned downstream of the isolation system and is configured to receive a mixture of the exhaust gas and the oxidizing gas; and   an oxygen injector fluidly coupled to at least one of the isolation system or the catalyst enclosure, wherein the oxidizing injector is positioned downstream of the furnace chamber and is configured to introduce the oxidizing gas into the exhaust gas.   
     
     
         11 . The furnace system of  claim 10 , wherein the isolation system comprises at least one of a check valve, a proportional valve, a pump, or a porous plug. 
     
     
         12 . The furnace system of  claim 10 , wherein the binder trap system comprises a binder trap cooler configured to adjust a temperature of the binder trap. 
     
     
         13 . The furnace system of  claim 10 , further comprising:
 a binder trap system bypass conduit fluidly coupled to the outlet downstream of the binder trap system and to the isolation system upstream of the binder trap system, wherein the binder trap system bypass conduit is configured to direct the exhaust gas to bypass the binder trap system.   
     
     
         14 . The furnace system of  claim 13 , wherein the bypass conduit includes at least one valve configured to optionally open the bypass conduit to allow the exhaust gas to bypass the binder trap system or to close the bypass conduit to allow the exhaust gas to flow through the binder trap system. 
     
     
         15 . A furnace system, comprising:
 a furnace chamber defining an interior region, wherein the furnace chamber is configured to maintain an atmosphere substantially free of oxygen within the interior region;   an outlet fluidly coupled to the furnace chamber for removal of an exhaust gas from the furnace chamber;   an isolation system fluidly coupled to the outlet, wherein the isolation system is configured to prevent a backflow of an oxidizing gas into the furnace chamber;   a binder cracking system fluidly coupled to the isolation system, wherein the binder cracking system is positioned downstream of the isolation system;   a catalyst enclosure comprising an oxidizing catalyst, wherein the catalyst enclosure is positioned downstream of the isolation system and is configured to receive a mixture of the exhaust gas and the oxidizing gas; and   an oxygen injector fluidly coupled to at least one of the isolation system or the catalyst enclosure, wherein the oxidizing injector is positioned downstream of the furnace chamber and is configured to introduce the oxidizing gas into the exhaust gas.   
     
     
         16 . The furnace system of  claim 15 , wherein isolation system comprises a check valve configured to prevent a backflow of the oxidizing gas into the furnace chamber. 
     
     
         17 . The furnace system of  claim 15 , wherein the binder cracking system comprises an enclosure substantially free of oxygen and a heater configured to heat the enclosure. 
     
     
         18 . The furnace system of  claim 17 , wherein the enclosure contains a catalyst configured to react with at least the portion of a component of the exhaust gas. 
     
     
         19 . The furnace system of  claim 17 , wherein the binder cracking system further comprises a steam source and a flame arrestor positioned downstream of the enclosure. 
     
     
         20 . The furnace system of  claim 17 , wherein the isolation system further comprises a venturi pump positioned downstream of the binder cracking system and is configured to prevent a backflow of the oxidizing gas into the furnace chamber.