US20150230293A1 - System for insulating an induction vacuum furnace and method of making same - Google Patents
System for insulating an induction vacuum furnace and method of making same Download PDFInfo
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- US20150230293A1 US20150230293A1 US14/424,038 US201314424038A US2015230293A1 US 20150230293 A1 US20150230293 A1 US 20150230293A1 US 201314424038 A US201314424038 A US 201314424038A US 2015230293 A1 US2015230293 A1 US 2015230293A1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/04—Crucible or pot furnaces adapted for treating the charge in vacuum or special atmosphere
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P19/00—Machines for simply fitting together or separating metal parts or objects, or metal and non-metal parts, whether or not involving some deformation; Tools or devices therefor so far as not provided for in other classes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/06—Crucible or pot furnaces heated electrically, e.g. induction crucible furnaces with or without any other source of heat
- F27B14/061—Induction furnaces
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/08—Details peculiar to crucible or pot furnaces
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
- F27B5/04—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated adapted for treating the charge in vacuum or special atmosphere
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
- F27B5/06—Details, accessories, or equipment peculiar to furnaces of these types
- F27B5/14—Arrangements of heating devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D11/00—Arrangement of elements for electric heating in or on furnaces
- F27D11/06—Induction heating, i.e. in which the material being heated, or its container or elements embodied therein, form the secondary of a transformer
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
- F27D7/06—Forming or maintaining special atmospheres or vacuum within heating chambers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D9/00—Cooling of furnaces or of charges therein
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F5/00—Coils
- H01F5/02—Coils wound on non-magnetic supports, e.g. formers
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
- H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/22—Furnaces without an endless core
- H05B6/24—Crucible furnaces
- H05B6/26—Crucible furnaces using vacuum or particular gas atmosphere
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
- F27B5/06—Details, accessories, or equipment peculiar to furnaces of these types
- F27B2005/062—Cooling elements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/04—Crucible or pot furnaces adapted for treating the charge in vacuum or special atmosphere
- F27B2014/045—Vacuum
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/06—Crucible or pot furnaces heated electrically, e.g. induction crucible furnaces with or without any other source of heat
- F27B14/061—Induction furnaces
- F27B2014/066—Construction of the induction furnace
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/08—Details peculiar to crucible or pot furnaces
- F27B2014/0825—Crucible or pot support
- F27B2014/0831—Support or means for the transport of crucibles
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/08—Details peculiar to crucible or pot furnaces
- F27B2014/0837—Cooling arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/08—Details peculiar to crucible or pot furnaces
- F27B2014/0887—Movement of the melt
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D9/00—Cooling of furnaces or of charges therein
- F27D2009/007—Cooling of charges therein
- F27D2009/0072—Cooling of charges therein the cooling medium being a gas
- F27D2009/0075—Cooling of charges therein the cooling medium being a gas in direct contact with the charge
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
- F27D2021/0057—Security or safety devices, e.g. for protection against heat, noise, pollution or too much duress; Ergonomic aspects
- F27D2021/0078—Security or safety devices, e.g. for protection against heat, noise, pollution or too much duress; Ergonomic aspects against the presence of an undesirable element in the atmosphere of the furnace
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/4902—Electromagnet, transformer or inductor
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49826—Assembling or joining
Definitions
- Embodiments of the invention relate generally to induction furnaces for heating a workpiece in an inert atmosphere or vacuum and, more particularly, to a system for providing an insulation package for an induction furnace having improved insulation properties at temperatures above 1200 degrees Celsius.
- Conventional induction furnaces include an induction heating system and a chamber that contains a susceptor that is susceptible to induction heating, with the chamber enclosing an inert atmosphere or vacuum therein.
- An electromagnetic coil sits outside the susceptor and receives high frequency alternating current from a power supply. The resulting alternating electromagnetic field heats the susceptor rapidly.
- the workpiece to be heated is placed in proximity to and generally within the susceptor so that when the susceptor is inductively heated by the induction heating system, the heat is transferred to the workpiece through radiation and/or conduction and convection. After a desired heating and processing of the workpiece is completed, the workpiece is then subsequently cooled in order to complete the heating/cooling cycle.
- Induction heating can be used to bond, harden or soften metals or other conductive materials in a wide variety of manufacturing processes.
- the intended outcome of the induction heating process e.g., bonding or hardening
- the furnace efficiency and cycle time as well as the size, geometry, and material properties of the workpiece are all factors that may be taken into account in a design of an induction furnace.
- Prior art induction furnaces typically operate at temperatures at or below 1200 degrees Celsius. For certain manufacturing processes and workpiece materials, however, it would be desirable to operate the induction furnace at temperatures above 1200 degrees Celsius. Prior art induction furnaces experience a number of negative effects when operating at temperatures above 1200 degrees Celsius. For example, the operating efficiency of the furnace and the temperature uniformity within the furnace is negatively affected. Further, dielectric breakdown tends to occur around the induction coils of the furnace at furnace operating temperatures above 1200 degrees Celsius.
- Embodiments of the invention overcome the aforementioned drawbacks by providing a system and method for insulating an induction vacuum furnace.
- an induction furnace for heating a workpiece includes a chamber, an insulation cylinder positioned within the chamber, and an induction coil positioned to surround at least a portion of the insulation cylinder.
- a susceptor is positioned within the insulation cylinder and inductively heated by the induction coil when a current is provided to the induction coil.
- An insulating jacket assembly including one of a carbide material and a refractory metal is positioned in a space between the insulating cylinder and the susceptor.
- an induction furnace in accordance with another aspect of the invention, includes a chamber having a susceptor positioned therein. An interior volume of the susceptor defines a zone within the chamber for heating a workpiece.
- the induction furnace also includes an insulation package having a fused quartz cylinder positioned around the susceptor and a graphite jacket positioned between the fused quartz cylinder and the susceptor.
- a coil surrounds the insulation package and is configured to inductively heat the interior volume of the susceptor when a current is provided to the induction coil.
- a method of making an induction furnace includes providing a vacuum chamber, coupling an insulation cylinder within the vacuum chamber, and coupling an induction coil to surround at least a portion of the insulation cylinder.
- the method also includes coupling a susceptor within the insulation cylinder and encapsulating the susceptor with an insulating jacket, wherein the insulating jacket comprises one of a carbide material and a refractory metal.
- FIG. 1 is a block schematic diagram of an induction furnace according to an embodiment of the invention.
- FIG. 2 is an additional diagram of the induction furnace of FIG. 1 where a workpiece is in a lowered position.
- FIG. 3 is a block schematic diagram of an induction furnace according to another embodiment of the invention.
- FIG. 4 is an additional diagram of the induction furnace of FIG. 3 where a workpiece is in a lowered position.
- FIG. 5 is a flowchart illustrating a technique for heating and cooling a workpiece using an induction furnace according to an embodiment of the invention.
- FIG. 6 is a block schematic diagram of an induction furnace according to an alternative embodiment of the invention.
- Induction furnace 100 includes an induction heating system 102 inside a chamber 104 .
- Induction heating system 102 includes an insulation package 106 comprising an insulation cylinder 108 and an insulating jacket assembly 110 .
- Insulation cylinder 108 includes a side wall 112 , a first cover 114 for sealing one end of cylinder 108 , and a second cover 116 for sealing the second end of cylinder 108 .
- Induction heating system 102 includes a coil 118 and a power supply (not shown) that provides an alternating current that flows through coil 118 during a heating cycle.
- Coil 118 is wound to form a helical shape within chamber 104 about insulation cylinder 108 as shown in FIG. 1 .
- a susceptor 120 Contained within insulation cylinder 108 is a susceptor 120 that is susceptible to induction heating. That is, when an alternating current flows through coil 118 , an alternating magnetic field is generated that induces eddy currents and other effects in susceptor 120 that cause the susceptor 120 to heat. The thermal energy that radiates from susceptor 120 is used to heat a workpiece 122 .
- Susceptor 120 is shown as being cylindrical, but other shapes can be used.
- Susceptor 120 is made of any material susceptible to induction heating, such as, for example, graphite, molybdenum, steel, and tungsten.
- Susceptor 120 is arranged within insulation cylinder 108 in chamber 104 .
- Insulation cylinder 108 is made from an insulative material that is not susceptible to induction heating such as, for example, fused quartz.
- Susceptor 120 includes a side wall 124 , a first cover 126 for sealing one end, and a second cover 128 for sealing the other end.
- a tray 130 for supporting workpiece 122 to be heated is connected to second cover 128 of susceptor 120 .
- susceptor 120 is shown as having closed ends, this need not be the case.
- the susceptor 120 can be in the form of a tube that is open at both ends or, for example, it can comprise one or more susceptor sheets.
- First cover 114 of cylinder 108 is coupled to chamber 104 via one or more posts 132 , which in an embodiment, is constructed of a ceramic material.
- First cover 126 of susceptor 120 is coupled to first cover 114 via one or more additional posts 134 .
- Insulating jacket assembly 110 includes a plurality of insulating sheets 136 arranged in layers to cover the exterior surfaces of susceptor 120 . As shown in FIG. 1 , insulating sheets 136 are contained in the space between insulation cylinder 108 and susceptor 120 to prevent any loose material of insulating sheets 136 from contaminating the rest of the vacuum chamber or in the components being processed in induction furnace 100 . In particular, a first portion 138 of insulating sheets 136 is positioned between outer surface 140 of side wall 124 of susceptor 120 and an inner surface 142 of side wall 112 of insulation cylinder 108 .
- a second portion 144 of insulating sheets 136 are positioned between a top surface 146 of first cover 126 of susceptor 120 and an upper, inside surface 148 of insulation cylinder 108 .
- a third portion 150 of insulating sheets 136 is positioned between a bottom surface 152 of second cover 128 and a lower, inside surface 154 of insulation cylinder 108 .
- Each layer of the insulating sheets 136 may be, for example, approximately 1 ⁇ 8 inch thick, and is woven at a frequency such that the material is transparent to induction.
- the first portion 138 of insulating sheets 136 includes three (3) individual layers wrapped around susceptor 120
- the second portion 144 of insulating sheets 136 includes four (4) individual layers sized to approximately match the geometry of the first cover 126 of susceptor 120
- third portion 150 of insulating sheets 136 includes ten (10) individual layers sized to approximately match the geometry of the second cover 128 of susceptor 120 .
- the number of layers of insulating sheets 136 as well as the geometry and thickness of each layer may be varied based on desired insulating characteristics.
- insulation package 106 further includes an upper insulating plate 156 positioned atop the second portion 144 of insulating sheets 136 and a lower insulating plate 158 positioned below the third portion 150 of insulating sheets 136 to further contain second and third portions 144 , 150 of insulating sheets 136 .
- Upper and lower insulating plates 156 , 158 retain insulating sheets 136 against susceptor 120 and provide additional insulation for susceptor 120 .
- upper insulating plate 156 and lower insulating plate 158 are constructed of graphite.
- Insulating sheets 136 which comprise carbides or refractory metals, insulate the outside of susceptor 120 and mitigate radiative heat loss.
- insulating sheets 136 are layers of graphite felt or wool.
- the graphite felt has a bulk density of approximately 0.10 g/cm 3 , a carbon content greater than approximately 99.5 percent, an ash content of approximately 0.05 percent, a thermal conductivity at 1500 degrees Celsius of approximately 0.08 W/mk, and a maximum process temperature of approximately 2400 degrees Celsius.
- insulating sheets 136 While graphite materials are inherently susceptible to inductive heating, the configuration and arrangement of insulating sheets 136 within induction furnace 100 relative to the other elements of the insulating package, including insulation cylinder 108 , minimizes the susceptibility of insulating sheets 136 to significant induction heating. Heat generated by induction heating system 102 is used to heat susceptor 120 rather than being lost on heating insulating sheets 136 . As such, susceptor 120 is idealized for heating. Further, insulating sheets 136 are arranged so as to not heat each other and to not heat coil 118 at the elevated operating temperatures within the heating zone 164 of susceptor 120 .
- the graphite felt has a number of benefits over a traditional insulation package. For example, graphite felt has reduced susceptibility to contamination, has no issue with thermal shock, and functions well in vacuum. Ceramics, on the other hand, are brittle and prone to fracture in the high temperature environment of the furnace, absorb moisture, and may be problematic to maintaining vacuum within the furnace. Glass wool and firebrick, other traditional insulating materials, are not robust to thermal shock, and expel moisture and particulates that contaminate the furnace environment. Molybdenum sheets and other materials that function as a thermal mirror need to be replaced frequency and require a long cooling cycle.
- insulating sheets 136 with insulation cylinder 108 also lends superior thermal performance as compared to a traditional insulation package constructed of ceramics, molybdenum sheets, glass wool, and/or firebrick.
- Graphite handles high temperatures well, is easy to machine, has a high resistivity, and is very efficient (e.g., approximately 85-90% efficient).
- insulating sheets 136 improve the heating cycle of induction furnace 100 and are approximately 60% more energy efficient and 30% more time efficient as compared to a traditional insulation.
- induction furnace 100 may be operated to heat a workpiece at temperatures greater than the previous limit of 1200 degrees Celsius without experiencing dielectric breakdown around the coil 118 of induction furnace 100 .
- induction furnace 100 may be operated at temperatures above 1900 degrees Celsius.
- insulating sheets 136 provide improved temperature control and reduced run-to-run variation. The improved insulation enables a reduction in power consumption and reduced cycle time.
- FIG. 1 illustrates induction heating system 102 in a raised or heating position where workpiece 122 is positioned within susceptor 120 and is ready for heating according to induction furnace principles as described above.
- induction heating system 102 is in a lowered position where access to workpiece 122 through a door 160 of chamber 104 is possible.
- Induction furnace 100 also includes a vacuum pump 162 for creating a vacuum within the chamber 104 .
- Door 160 forms a hermetic seal when closed such that a vacuum created by vacuum pump 162 in an interior volume of chamber 104 is hermetically isolated from an ambient environment outside chamber 104 .
- the workpiece 122 In operation of induction furnace 102 , the workpiece 122 is in a raised or heating position, i.e., within in a “heating zone” 164 defined by susceptor 120 , when a heating operation is being undertaken.
- the workpiece 122 is then moved to the lowered or cooling position, i.e., within in a “cooling zone” 166 outside of the susceptor 120 , when a cooling operation is being undertaken.
- Moving workpiece 122 to the cooling zone 166 after completion of the heating of workpiece 122 allows for a reduction in the primary overall furnace cycle time. That is, the time required for cooling workpiece 122 is an important factor in the overall furnace cycle time, as traditional cooling becomes increasingly inefficient at lower temperatures. According to embodiments the invention, faster cooling times are achieved at lower temperatures by dropping the parts out of the hot zone 164 and into the cool zone 166 of the vacuum chamber 104 .
- induction furnace 102 is constructed so as to facilitate movement of the workpiece 122 between the heating zone 164 and the cooling zone 166 while maintaining a desired vacuum pressure within chamber 104 , and is further constructed to include elements to enhance cooling of the workpiece 122 .
- induction furnace 102 is shown as including a cooling system 168 for cooling chamber 104 after the workpiece 122 has been heated as desired.
- Cooling system 168 can include a heat exchanger 170 and a blower 172 . Hot gas within the chamber 104 is drawn into the heat exchanger 170 , and cooler gas is blown back into chamber 104 by blower 172 .
- Bellows system 174 includes a pair of vacuum-sealed bellows 176 , 178 attached to respective coupling device 180 , 182 that are coupled to chamber 104 .
- a linear actuator 184 such as a piston is coupled to chamber 104 and is coupled to bellows 176 , 178 via a plate 186 .
- linear actuator 184 may be a pneumatic or hydraulic piston, an electro-mechanical piston, a manual actuator, or the like.
- bellows 176 , 178 and coupling devices 180 , 182 are fluidly coupled to the interior volume of chamber 104 .
- movement of linear actuator 184 from the outside of chamber 104 allows the atmosphere and pressure inside chamber 104 to be maintained when plate 186 is moved either away from or toward chamber 104 . Accordingly, workpiece 122 can be lowered from heating zone 164 to cooling zone 166 .
- the movement to the cooling position or zone may be governed by a threshold time and/or temperature, and may be triggered by pressure or RGA or partial pressure, or rates of any of these.
- the part or workpiece 122 is dropped into the cool section 166 after the part has cooled to approximately 1200° C. This effectively opens the insulated hot zone 164 and allows the cooling gas to pass across the heated parts 122 . Once the workpiece 122 drops out of the hot zone 164 , the workpiece 122 experiences improved radiative and convective cooling.
- the area of the cooling zone 166 within chamber 104 has unique temperature control (i.e., ability to quench from high temperature to a lower, controlled temperature), which is particularly useful for heat treating applications. Due to the multi-zone configuration of the vacuum chamber, cooling times may be greatly reduced when compared with cooling inside heating zone 164 , and faster cycle times can be met.
- a technique 188 for heating and cooling a workpiece is illustrated according to an embodiment of the invention.
- certain steps in the technique 188 are considered to be optional, as they would only be performed when the induction furnace is of a type as shown in FIGS. 3 and 4 or in certain workpiece heating/cooling processes.
- These optional steps in technique 188 are shown in phantom in FIG. 5 , so as to highlight that they may not be performed in induction furnaces having a certain geometry/construction.
- the technique begins at STEP 190 with loading of a workpiece 122 into the furnace 100 , such as by way of door 160 , with the piece being positioned on tray 130 when it is in a lowered position.
- the furnace door 160 is then closed, and the technique continues at STEP 192 , where the interior of the furnace 100 is brought to a high vacuum (when the induction furnace is configured as a vacuum induction furnace), such as a 10 ⁇ 7 vacuum pressure, by operation of vacuum pump 162 .
- the workpiece 122 is then raised into the upper hot zone chamber 164 formed by insulating cylinder 108 and susceptor 120 at STEP 194 .
- the workpiece 122 is flushed with argon, and the interior of the furnace 100 may then be subsequently brought again to a high vacuum depending on the furnace configuration.
- the workpiece then begins to be heated at STEP 198 , with an inert gas (e.g., nitrogen) then being introduced at partial pressure at STEP 200 .
- the workpiece 122 is heated to 200-600° C. with the flowing inert gas to expedite removal of off-gassing, and the technique then continues at STEP 202 where the furnace chamber may again be (optionally) returned to a high vacuum via vacuum pump 162 and heated to a desired processing temperature.
- a material for coating the workpiece is then introduced if desired at STEP 204 .
- the workpiece is begun to cool at STEP 206 , with such cooling occurring inside the vacuum in certain embodiments.
- the workpiece is cooled to a temperature below a cooling threshold, and the workpiece is lowered out of the heating zone 164 and into the cooling zone 166 after the threshold has been met using the vacuum sealed bellows system 174 at STEP 208 .
- the vacuum pressure created inside the furnace may be maintained when moving the workpiece to the cooling zone 166 .
- a quenching gas such as helium, argon, or nitrogen is then injected at STEP 210 , with the gas being injected at atmospheric pressure according to one embodiment.
- gas may be injected at STEP 210 at either or both of the high and low workpiece positions, as faster cooling times can be achieved at lower temperatures by dropping the workpiece out of the hot zone 164 into the cool section 166 of the vacuum chamber 104 .
- the process of injecting gas at STEP 210 can incorporate a repositioning of the workpiece down into the cooling zone 166 outside of susceptor 120 by lowering hot zone tray 130 .
- the lowering of the workpiece 122 down into the cooling zone 166 may be governed by a threshold time and/or temperature, and may be triggered by pressure or RGA or partial pressure, or rates of any of these.
- the workpiece 122 is dropped into the cool section after the workpiece has cooled to approximately 1200° C., as further cooling below this threshold temperature is achieved most efficiently by passing cooling gas across the heated workpiece 122 when it is located in the cooling zone 166 .
- the cooling time of the workpiece can be reduced greatly and faster cycle times can be met.
- an induction furnace 220 is shown according to another embodiment of the invention. While the induction furnace 220 is constructed to have an insulating jacket assembly 110 identical to that shown and described with respect to FIGS. 1-4 (with the insulating sheets 136 arranged in layers to cover the exterior surfaces of susceptor 120 ), the induction furnace 220 shown in FIG. 6 is constructed as a furnace that does not operate at a vacuum, but instead provides cooling to a workpiece 118 via a gasflow that has a non-recirculated flow path. As shown in FIG. 6 , gas blower 144 provides a supply of cooling gas into the interior volume of the chamber 104 that is blown across the workpiece 118 .
- the cooling gas After the cooling gas is blown across the workpiece 118 , it is not recirculated through a cooling system for subsequent use, but is instead vented from the chamber 104 of induction furnace 220 out through an exit port 222 and to the ambient environment after cooling of the workpiece is performed.
- an induction furnace for heating a workpiece includes a chamber, an insulation cylinder positioned within the chamber, and an induction coil positioned to surround at least a portion of the insulation cylinder.
- a susceptor is positioned within the insulation cylinder and inductively heated by the induction coil when a current is provided to the induction coil.
- An insulating jacket assembly including one of a carbide material and a refractory metal is positioned in a space between the insulating cylinder and the susceptor.
- an induction furnace includes a chamber having a susceptor positioned therein. An interior volume of the susceptor defines a zone within the chamber for heating a workpiece.
- the induction furnace also includes an insulation package having a fused quartz cylinder positioned around the susceptor and a graphite jacket positioned between the fused quartz cylinder and the susceptor.
- a coil surrounds the insulation package and is configured to inductively heat the interior volume of the susceptor when a current is provided to the induction coil.
- a method of making an induction furnace includes providing a vacuum chamber, coupling an insulation cylinder within the vacuum chamber, and coupling an induction coil to surround at least a portion of the insulation cylinder.
- the method also includes coupling a susceptor within the insulation cylinder and encapsulating the susceptor with an insulating jacket, wherein the insulating jacket comprises one of a carbide material and a refractory metal.
Abstract
Description
- This is a national stage application under 35 U.S.C. §371(c) of prior-filed, co-pending, PCT application serial number PCT/US2013/038796, filed on Apr. 30, 2013, which claims priority to U.S. Provisional Application No. 61/694,869, filed Aug. 30, 2012, the contents of which are incorporated herein by reference.
- Embodiments of the invention relate generally to induction furnaces for heating a workpiece in an inert atmosphere or vacuum and, more particularly, to a system for providing an insulation package for an induction furnace having improved insulation properties at temperatures above 1200 degrees Celsius.
- Conventional induction furnaces include an induction heating system and a chamber that contains a susceptor that is susceptible to induction heating, with the chamber enclosing an inert atmosphere or vacuum therein. An electromagnetic coil sits outside the susceptor and receives high frequency alternating current from a power supply. The resulting alternating electromagnetic field heats the susceptor rapidly. The workpiece to be heated is placed in proximity to and generally within the susceptor so that when the susceptor is inductively heated by the induction heating system, the heat is transferred to the workpiece through radiation and/or conduction and convection. After a desired heating and processing of the workpiece is completed, the workpiece is then subsequently cooled in order to complete the heating/cooling cycle.
- Induction heating can be used to bond, harden or soften metals or other conductive materials in a wide variety of manufacturing processes. The intended outcome of the induction heating process (e.g., bonding or hardening), the furnace efficiency and cycle time, as well as the size, geometry, and material properties of the workpiece are all factors that may be taken into account in a design of an induction furnace.
- Prior art induction furnaces typically operate at temperatures at or below 1200 degrees Celsius. For certain manufacturing processes and workpiece materials, however, it would be desirable to operate the induction furnace at temperatures above 1200 degrees Celsius. Prior art induction furnaces experience a number of negative effects when operating at temperatures above 1200 degrees Celsius. For example, the operating efficiency of the furnace and the temperature uniformity within the furnace is negatively affected. Further, dielectric breakdown tends to occur around the induction coils of the furnace at furnace operating temperatures above 1200 degrees Celsius.
- It would therefore be desirable to design an induction furnace capable of operating at temperatures above 1200 degrees Celsius, while maintaining efficient and uniform heating and preventing dielectric breakdown around the induction coils.
- Embodiments of the invention overcome the aforementioned drawbacks by providing a system and method for insulating an induction vacuum furnace.
- In accordance with one aspect of the invention, an induction furnace for heating a workpiece includes a chamber, an insulation cylinder positioned within the chamber, and an induction coil positioned to surround at least a portion of the insulation cylinder. A susceptor is positioned within the insulation cylinder and inductively heated by the induction coil when a current is provided to the induction coil. An insulating jacket assembly including one of a carbide material and a refractory metal is positioned in a space between the insulating cylinder and the susceptor.
- In accordance with another aspect of the invention, an induction furnace includes a chamber having a susceptor positioned therein. An interior volume of the susceptor defines a zone within the chamber for heating a workpiece. The induction furnace also includes an insulation package having a fused quartz cylinder positioned around the susceptor and a graphite jacket positioned between the fused quartz cylinder and the susceptor. A coil surrounds the insulation package and is configured to inductively heat the interior volume of the susceptor when a current is provided to the induction coil.
- In accordance with yet another aspect of the invention, a method of making an induction furnace includes providing a vacuum chamber, coupling an insulation cylinder within the vacuum chamber, and coupling an induction coil to surround at least a portion of the insulation cylinder. The method also includes coupling a susceptor within the insulation cylinder and encapsulating the susceptor with an insulating jacket, wherein the insulating jacket comprises one of a carbide material and a refractory metal.
- These and other advantages and features will be more readily understood from the following detailed description of embodiments of the invention that is provided in connection with the accompanying drawings.
- The drawings illustrate embodiments presently contemplated for carrying out the invention.
- In the drawings:
-
FIG. 1 is a block schematic diagram of an induction furnace according to an embodiment of the invention. -
FIG. 2 is an additional diagram of the induction furnace ofFIG. 1 where a workpiece is in a lowered position. -
FIG. 3 is a block schematic diagram of an induction furnace according to another embodiment of the invention. -
FIG. 4 is an additional diagram of the induction furnace ofFIG. 3 where a workpiece is in a lowered position. -
FIG. 5 is a flowchart illustrating a technique for heating and cooling a workpiece using an induction furnace according to an embodiment of the invention. -
FIG. 6 is a block schematic diagram of an induction furnace according to an alternative embodiment of the invention. - Referring to
FIGS. 1 and 2 , the major components of aninduction furnace 100 are shown.Induction furnace 100 includes aninduction heating system 102 inside achamber 104.Induction heating system 102 includes aninsulation package 106 comprising aninsulation cylinder 108 and aninsulating jacket assembly 110.Insulation cylinder 108 includes aside wall 112, afirst cover 114 for sealing one end ofcylinder 108, and asecond cover 116 for sealing the second end ofcylinder 108.Induction heating system 102 includes acoil 118 and a power supply (not shown) that provides an alternating current that flows throughcoil 118 during a heating cycle.Coil 118 is wound to form a helical shape withinchamber 104 aboutinsulation cylinder 108 as shown inFIG. 1 . - Contained within
insulation cylinder 108 is asusceptor 120 that is susceptible to induction heating. That is, when an alternating current flows throughcoil 118, an alternating magnetic field is generated that induces eddy currents and other effects insusceptor 120 that cause thesusceptor 120 to heat. The thermal energy that radiates fromsusceptor 120 is used to heat aworkpiece 122.Susceptor 120 is shown as being cylindrical, but other shapes can be used.Susceptor 120 is made of any material susceptible to induction heating, such as, for example, graphite, molybdenum, steel, and tungsten.Susceptor 120 is arranged withininsulation cylinder 108 inchamber 104.Insulation cylinder 108 is made from an insulative material that is not susceptible to induction heating such as, for example, fused quartz. -
Susceptor 120 includes aside wall 124, afirst cover 126 for sealing one end, and asecond cover 128 for sealing the other end. Atray 130 for supportingworkpiece 122 to be heated is connected tosecond cover 128 ofsusceptor 120. Althoughsusceptor 120 is shown as having closed ends, this need not be the case. For example, thesusceptor 120 can be in the form of a tube that is open at both ends or, for example, it can comprise one or more susceptor sheets.First cover 114 ofcylinder 108 is coupled tochamber 104 via one ormore posts 132, which in an embodiment, is constructed of a ceramic material.First cover 126 ofsusceptor 120 is coupled tofirst cover 114 via one or moreadditional posts 134. - Insulating
jacket assembly 110 includes a plurality ofinsulating sheets 136 arranged in layers to cover the exterior surfaces ofsusceptor 120. As shown inFIG. 1 ,insulating sheets 136 are contained in the space betweeninsulation cylinder 108 andsusceptor 120 to prevent any loose material ofinsulating sheets 136 from contaminating the rest of the vacuum chamber or in the components being processed ininduction furnace 100. In particular, afirst portion 138 ofinsulating sheets 136 is positioned betweenouter surface 140 ofside wall 124 ofsusceptor 120 and aninner surface 142 ofside wall 112 ofinsulation cylinder 108. Asecond portion 144 ofinsulating sheets 136 are positioned between atop surface 146 offirst cover 126 ofsusceptor 120 and an upper, insidesurface 148 ofinsulation cylinder 108. Athird portion 150 ofinsulating sheets 136 is positioned between abottom surface 152 ofsecond cover 128 and a lower, insidesurface 154 ofinsulation cylinder 108. - Each layer of the
insulating sheets 136 may be, for example, approximately ⅛ inch thick, and is woven at a frequency such that the material is transparent to induction. In one exemplary embodiment, thefirst portion 138 ofinsulating sheets 136 includes three (3) individual layers wrapped aroundsusceptor 120, thesecond portion 144 ofinsulating sheets 136 includes four (4) individual layers sized to approximately match the geometry of thefirst cover 126 ofsusceptor 120, andthird portion 150 ofinsulating sheets 136 includes ten (10) individual layers sized to approximately match the geometry of thesecond cover 128 ofsusceptor 120. However, one skilled in the art will recognize that the number of layers of insulatingsheets 136 as well as the geometry and thickness of each layer may be varied based on desired insulating characteristics. - In one embodiment,
insulation package 106 further includes an upper insulatingplate 156 positioned atop thesecond portion 144 of insulatingsheets 136 and a lower insulatingplate 158 positioned below thethird portion 150 of insulatingsheets 136 to further contain second andthird portions sheets 136. Upper and lower insulatingplates retain insulating sheets 136 againstsusceptor 120 and provide additional insulation forsusceptor 120. In an exemplary embodiment, upper insulatingplate 156 and lower insulatingplate 158 are constructed of graphite. - Insulating
sheets 136, which comprise carbides or refractory metals, insulate the outside ofsusceptor 120 and mitigate radiative heat loss. In an exemplary embodiment, insulatingsheets 136 are layers of graphite felt or wool. The graphite felt has a bulk density of approximately 0.10 g/cm3, a carbon content greater than approximately 99.5 percent, an ash content of approximately 0.05 percent, a thermal conductivity at 1500 degrees Celsius of approximately 0.08 W/mk, and a maximum process temperature of approximately 2400 degrees Celsius. While graphite materials are inherently susceptible to inductive heating, the configuration and arrangement of insulatingsheets 136 withininduction furnace 100 relative to the other elements of the insulating package, includinginsulation cylinder 108, minimizes the susceptibility of insulatingsheets 136 to significant induction heating. Heat generated byinduction heating system 102 is used to heatsusceptor 120 rather than being lost onheating insulating sheets 136. As such,susceptor 120 is idealized for heating. Further, insulatingsheets 136 are arranged so as to not heat each other and to not heatcoil 118 at the elevated operating temperatures within theheating zone 164 ofsusceptor 120. - The graphite felt has a number of benefits over a traditional insulation package. For example, graphite felt has reduced susceptibility to contamination, has no issue with thermal shock, and functions well in vacuum. Ceramics, on the other hand, are brittle and prone to fracture in the high temperature environment of the furnace, absorb moisture, and may be problematic to maintaining vacuum within the furnace. Glass wool and firebrick, other traditional insulating materials, are not robust to thermal shock, and expel moisture and particulates that contaminate the furnace environment. Molybdenum sheets and other materials that function as a thermal mirror need to be replaced frequency and require a long cooling cycle.
- Using insulating
sheets 136 withinsulation cylinder 108 also lends superior thermal performance as compared to a traditional insulation package constructed of ceramics, molybdenum sheets, glass wool, and/or firebrick. Graphite handles high temperatures well, is easy to machine, has a high resistivity, and is very efficient (e.g., approximately 85-90% efficient). Thus, insulatingsheets 136 improve the heating cycle ofinduction furnace 100 and are approximately 60% more energy efficient and 30% more time efficient as compared to a traditional insulation. - As a result of the enhanced insulating properties gained by the inclusion of insulating
sheets 136,induction furnace 100 may be operated to heat a workpiece at temperatures greater than the previous limit of 1200 degrees Celsius without experiencing dielectric breakdown around thecoil 118 ofinduction furnace 100. For example,induction furnace 100 may be operated at temperatures above 1900 degrees Celsius. Also, insulatingsheets 136 provide improved temperature control and reduced run-to-run variation. The improved insulation enables a reduction in power consumption and reduced cycle time. -
FIG. 1 illustratesinduction heating system 102 in a raised or heating position whereworkpiece 122 is positioned withinsusceptor 120 and is ready for heating according to induction furnace principles as described above. As shown inFIG. 2 ,induction heating system 102 is in a lowered position where access toworkpiece 122 through adoor 160 ofchamber 104 is possible.Induction furnace 100 also includes avacuum pump 162 for creating a vacuum within thechamber 104.Door 160 forms a hermetic seal when closed such that a vacuum created byvacuum pump 162 in an interior volume ofchamber 104 is hermetically isolated from an ambient environment outsidechamber 104. - In operation of
induction furnace 102, theworkpiece 122 is in a raised or heating position, i.e., within in a “heating zone” 164 defined bysusceptor 120, when a heating operation is being undertaken. Theworkpiece 122 is then moved to the lowered or cooling position, i.e., within in a “cooling zone” 166 outside of thesusceptor 120, when a cooling operation is being undertaken. Movingworkpiece 122 to thecooling zone 166 after completion of the heating ofworkpiece 122 allows for a reduction in the primary overall furnace cycle time. That is, the time required for coolingworkpiece 122 is an important factor in the overall furnace cycle time, as traditional cooling becomes increasingly inefficient at lower temperatures. According to embodiments the invention, faster cooling times are achieved at lower temperatures by dropping the parts out of thehot zone 164 and into thecool zone 166 of thevacuum chamber 104. - According to an exemplary embodiment of the invention,
induction furnace 102 is constructed so as to facilitate movement of theworkpiece 122 between theheating zone 164 and thecooling zone 166 while maintaining a desired vacuum pressure withinchamber 104, and is further constructed to include elements to enhance cooling of theworkpiece 122. Referring now toFIGS. 3 and 4 ,induction furnace 102 is shown as including acooling system 168 for coolingchamber 104 after theworkpiece 122 has been heated as desired.Cooling system 168 can include aheat exchanger 170 and ablower 172. Hot gas within thechamber 104 is drawn into theheat exchanger 170, and cooler gas is blown back intochamber 104 byblower 172. - After completion of a heating of
workpiece 122, thesecond cover 128 andtray 130 are dropped using a vacuum-sealedbellows system 174 attached tosecond cover 116.Bellows system 174 includes a pair of vacuum-sealedbellows respective coupling device chamber 104. Alinear actuator 184 such as a piston is coupled tochamber 104 and is coupled tobellows plate 186. Embodiments of the invention contemplate thatlinear actuator 184 may be a pneumatic or hydraulic piston, an electro-mechanical piston, a manual actuator, or the like. The interior volumes ofbellows coupling devices chamber 104. In this manner, movement oflinear actuator 184 from the outside ofchamber 104 allows the atmosphere and pressure insidechamber 104 to be maintained whenplate 186 is moved either away from or towardchamber 104. Accordingly,workpiece 122 can be lowered fromheating zone 164 to coolingzone 166. - According to various embodiments, the movement to the cooling position or zone may be governed by a threshold time and/or temperature, and may be triggered by pressure or RGA or partial pressure, or rates of any of these. In one embodiment, the part or
workpiece 122 is dropped into thecool section 166 after the part has cooled to approximately 1200° C. This effectively opens the insulatedhot zone 164 and allows the cooling gas to pass across theheated parts 122. Once theworkpiece 122 drops out of thehot zone 164, theworkpiece 122 experiences improved radiative and convective cooling. The area of thecooling zone 166 withinchamber 104 has unique temperature control (i.e., ability to quench from high temperature to a lower, controlled temperature), which is particularly useful for heat treating applications. Due to the multi-zone configuration of the vacuum chamber, cooling times may be greatly reduced when compared with cooling insideheating zone 164, and faster cycle times can be met. - Referring now to
FIG. 5 , and with continued reference to the furnace ofFIGS. 3 and 4 , atechnique 188 for heating and cooling a workpiece is illustrated according to an embodiment of the invention. As illustrated inFIG. 5 , certain steps in thetechnique 188 are considered to be optional, as they would only be performed when the induction furnace is of a type as shown inFIGS. 3 and 4 or in certain workpiece heating/cooling processes. These optional steps intechnique 188 are shown in phantom inFIG. 5 , so as to highlight that they may not be performed in induction furnaces having a certain geometry/construction. - As shown in
FIG. 5 , the technique begins atSTEP 190 with loading of aworkpiece 122 into thefurnace 100, such as by way ofdoor 160, with the piece being positioned ontray 130 when it is in a lowered position. Thefurnace door 160 is then closed, and the technique continues atSTEP 192, where the interior of thefurnace 100 is brought to a high vacuum (when the induction furnace is configured as a vacuum induction furnace), such as a 10−7 vacuum pressure, by operation ofvacuum pump 162. Theworkpiece 122 is then raised into the upperhot zone chamber 164 formed by insulatingcylinder 108 andsusceptor 120 atSTEP 194. At STEP 196, theworkpiece 122 is flushed with argon, and the interior of thefurnace 100 may then be subsequently brought again to a high vacuum depending on the furnace configuration. The workpiece then begins to be heated atSTEP 198, with an inert gas (e.g., nitrogen) then being introduced at partial pressure atSTEP 200. Theworkpiece 122 is heated to 200-600° C. with the flowing inert gas to expedite removal of off-gassing, and the technique then continues atSTEP 202 where the furnace chamber may again be (optionally) returned to a high vacuum viavacuum pump 162 and heated to a desired processing temperature. A material for coating the workpiece is then introduced if desired atSTEP 204. - The workpiece is begun to cool at
STEP 206, with such cooling occurring inside the vacuum in certain embodiments. According to an embodiment of the invention, the workpiece is cooled to a temperature below a cooling threshold, and the workpiece is lowered out of theheating zone 164 and into thecooling zone 166 after the threshold has been met using the vacuum sealedbellows system 174 atSTEP 208. In this manner, the vacuum pressure created inside the furnace may be maintained when moving the workpiece to thecooling zone 166. A quenching gas such as helium, argon, or nitrogen is then injected atSTEP 210, with the gas being injected at atmospheric pressure according to one embodiment. - According to various embodiments, gas may be injected at
STEP 210 at either or both of the high and low workpiece positions, as faster cooling times can be achieved at lower temperatures by dropping the workpiece out of thehot zone 164 into thecool section 166 of thevacuum chamber 104. Thus, the process of injecting gas atSTEP 210 can incorporate a repositioning of the workpiece down into thecooling zone 166 outside ofsusceptor 120 by loweringhot zone tray 130. As set forth above, the lowering of theworkpiece 122 down into thecooling zone 166 may be governed by a threshold time and/or temperature, and may be triggered by pressure or RGA or partial pressure, or rates of any of these. In one embodiment, theworkpiece 122 is dropped into the cool section after the workpiece has cooled to approximately 1200° C., as further cooling below this threshold temperature is achieved most efficiently by passing cooling gas across theheated workpiece 122 when it is located in thecooling zone 166. By selectively positioning theworkpiece 122 in thehot zone 164 and thecooling zone 166, the cooling time of the workpiece can be reduced greatly and faster cycle times can be met. - Referring now to
FIG. 6 , aninduction furnace 220 is shown according to another embodiment of the invention. While theinduction furnace 220 is constructed to have an insulatingjacket assembly 110 identical to that shown and described with respect toFIGS. 1-4 (with the insulatingsheets 136 arranged in layers to cover the exterior surfaces of susceptor 120), theinduction furnace 220 shown inFIG. 6 is constructed as a furnace that does not operate at a vacuum, but instead provides cooling to aworkpiece 118 via a gasflow that has a non-recirculated flow path. As shown inFIG. 6 ,gas blower 144 provides a supply of cooling gas into the interior volume of thechamber 104 that is blown across theworkpiece 118. After the cooling gas is blown across theworkpiece 118, it is not recirculated through a cooling system for subsequent use, but is instead vented from thechamber 104 ofinduction furnace 220 out through anexit port 222 and to the ambient environment after cooling of the workpiece is performed. - Therefore, according to one embodiment of the invention, an induction furnace for heating a workpiece includes a chamber, an insulation cylinder positioned within the chamber, and an induction coil positioned to surround at least a portion of the insulation cylinder. A susceptor is positioned within the insulation cylinder and inductively heated by the induction coil when a current is provided to the induction coil. An insulating jacket assembly including one of a carbide material and a refractory metal is positioned in a space between the insulating cylinder and the susceptor.
- According to another embodiment of the invention, an induction furnace includes a chamber having a susceptor positioned therein. An interior volume of the susceptor defines a zone within the chamber for heating a workpiece. The induction furnace also includes an insulation package having a fused quartz cylinder positioned around the susceptor and a graphite jacket positioned between the fused quartz cylinder and the susceptor. A coil surrounds the insulation package and is configured to inductively heat the interior volume of the susceptor when a current is provided to the induction coil.
- According to yet another embodiment of the invention, a method of making an induction furnace includes providing a vacuum chamber, coupling an insulation cylinder within the vacuum chamber, and coupling an induction coil to surround at least a portion of the insulation cylinder. The method also includes coupling a susceptor within the insulation cylinder and encapsulating the susceptor with an insulating jacket, wherein the insulating jacket comprises one of a carbide material and a refractory metal.
- This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims (20)
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US14/424,038 US20150230293A1 (en) | 2012-08-30 | 2013-04-30 | System for insulating an induction vacuum furnace and method of making same |
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US14/424,038 US20150230293A1 (en) | 2012-08-30 | 2013-04-30 | System for insulating an induction vacuum furnace and method of making same |
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US14/422,524 Expired - Fee Related US9657992B2 (en) | 2012-08-30 | 2013-05-03 | System for maintaining interior volume integrity in an induction vacuum furnace and method of making same |
US14/422,289 Abandoned US20150226485A1 (en) | 2012-08-30 | 2013-05-06 | System for gas purification in an induction vacuum furnace and method of making same |
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US14/422,289 Abandoned US20150226485A1 (en) | 2012-08-30 | 2013-05-06 | System for gas purification in an induction vacuum furnace and method of making same |
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Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2743306A (en) * | 1953-08-12 | 1956-04-24 | Carborundum Co | Induction furnace |
US3972704A (en) * | 1971-04-19 | 1976-08-03 | Sherwood Refractories, Inc. | Apparatus for making vitreous silica receptacles |
US4604510A (en) * | 1985-05-20 | 1986-08-05 | Tocco, Inc. | Method and apparatus for heat treating camshafts |
US5713979A (en) * | 1992-05-14 | 1998-02-03 | Tsl Group Plc | Heat treatment facility for synthetic vitreous silica bodies |
US20030209540A1 (en) * | 2002-05-09 | 2003-11-13 | Girish Dahake | Induction furnace for heating a workpiece in an inert atmosphere or vacuum |
US20070128569A1 (en) * | 2005-12-07 | 2007-06-07 | Ajax Tocco Magnethermic Corporation | Furnace alignment system |
US8242420B2 (en) * | 2008-08-31 | 2012-08-14 | Inductotherm Corp. | Directional solidification of silicon by electric induction susceptor heating in a controlled environment |
Family Cites Families (28)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3614284A (en) | 1969-04-12 | 1971-10-19 | Leybold Heraeus Verwaltung | Melting furnace with movable current carrying leads for a consumable electrode |
US4022939A (en) | 1975-12-18 | 1977-05-10 | Western Electric Company, Inc. | Synchronous shielding in vacuum deposition system |
US5219051A (en) * | 1991-10-25 | 1993-06-15 | Honeywell Inc. | Folded viscous damper |
US5257927A (en) * | 1991-11-01 | 1993-11-02 | Holman Boiler Works, Inc. | Low NOx burner |
US5178316A (en) | 1992-02-07 | 1993-01-12 | General Electric Company | Brazed X-ray tube anode |
US5611476C1 (en) | 1996-01-18 | 2002-02-26 | Btu Int | Solder reflow convection furnace employing flux handling and gas densification systems |
US6062851A (en) * | 1998-10-23 | 2000-05-16 | The B. F. Goodrich Company | Combination CVI/CVD and heat treat susceptor lid |
US6649887B2 (en) | 2001-03-30 | 2003-11-18 | General Electric Company | Apparatus and method for protective atmosphere induction brazing of complex geometries |
FR2826377B1 (en) * | 2001-06-26 | 2003-09-05 | Commissariat Energie Atomique | DEVICE FOR MANUFACTURING COOLING ALLOY CRYSTALS AND CONTROLLED SOLIDIFICATION OF A LIQUID MATERIAL |
US6724803B2 (en) * | 2002-04-04 | 2004-04-20 | Ucar Carbon Company Inc. | Induction furnace for high temperature operation |
US8372205B2 (en) | 2003-05-09 | 2013-02-12 | Applied Materials, Inc. | Reducing electrostatic charge by roughening the susceptor |
US7424045B2 (en) * | 2004-09-01 | 2008-09-09 | Wilcox Dale R | Method and apparatus for heating a workpiece in an inert atmosphere or in vacuum |
US7413793B2 (en) * | 2004-10-21 | 2008-08-19 | Graftech International Holdings Inc. | Induction furnace with unique carbon foam insulation |
JP2006206351A (en) * | 2005-01-26 | 2006-08-10 | Tdk Corp | Pulling-down apparatus and vessel used for the apparatus |
JP4896899B2 (en) | 2007-01-31 | 2012-03-14 | 東京エレクトロン株式会社 | Substrate processing apparatus and particle adhesion preventing method |
US7968044B2 (en) | 2007-04-30 | 2011-06-28 | Spraying Systems Co. | Sinter processing system |
JP4332203B2 (en) * | 2007-09-27 | 2009-09-16 | 新日本製鐵株式会社 | Insulation structure of induction heating coil |
JP5029382B2 (en) | 2008-01-22 | 2012-09-19 | 東京エレクトロン株式会社 | Processing apparatus and processing method |
GB2458964A (en) * | 2008-04-04 | 2009-10-07 | Elmelin Plc | Induction furnace lining |
US8931429B2 (en) * | 2008-05-05 | 2015-01-13 | United Technologies Corporation | Impingement part cooling |
US20090325386A1 (en) * | 2008-06-02 | 2009-12-31 | Mattson Technology, Inc. | Process and System For Varying the Exposure to a Chemical Ambient in a Process Chamber |
US8571085B2 (en) * | 2008-06-25 | 2013-10-29 | Ajax Tocco Magnethermic Corporation | Induction furnace for the controllable melting of powder/granular materials |
CN102165278B (en) | 2008-09-26 | 2013-09-25 | 株式会社爱发科 | Smelting furnace |
NO328469B1 (en) * | 2008-10-31 | 2010-02-22 | Elkem As | Induction furnace for smelting of metal, liner for induction furnace and process for making such liner |
JP2010205922A (en) * | 2009-03-03 | 2010-09-16 | Canon Anelva Corp | Substrate heat treatment apparatus and method of manufacturing substrate |
IT1394098B1 (en) | 2009-03-24 | 2012-05-25 | Brembo Ceramic Brake Systems Spa | INDUCTION OVEN AND INFILTRATION PROCESS |
US8431878B2 (en) * | 2009-03-26 | 2013-04-30 | Novocamin Incorporated | High temperature furnace using microwave energy |
JP5700323B2 (en) * | 2009-06-08 | 2015-04-15 | 独立行政法人物質・材料研究機構 | Metal heat treatment furnace |
-
2013
- 2013-03-15 WO PCT/US2013/031871 patent/WO2014035480A1/en active Application Filing
- 2013-04-30 WO PCT/US2013/038796 patent/WO2014035490A2/en active Application Filing
- 2013-04-30 US US14/424,038 patent/US20150230293A1/en not_active Abandoned
- 2013-05-03 WO PCT/US2013/039479 patent/WO2014035491A1/en active Application Filing
- 2013-05-03 US US14/422,524 patent/US9657992B2/en not_active Expired - Fee Related
- 2013-05-06 WO PCT/US2013/039737 patent/WO2014035492A1/en active Application Filing
- 2013-05-06 US US14/422,289 patent/US20150226485A1/en not_active Abandoned
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2743306A (en) * | 1953-08-12 | 1956-04-24 | Carborundum Co | Induction furnace |
US3972704A (en) * | 1971-04-19 | 1976-08-03 | Sherwood Refractories, Inc. | Apparatus for making vitreous silica receptacles |
US4604510A (en) * | 1985-05-20 | 1986-08-05 | Tocco, Inc. | Method and apparatus for heat treating camshafts |
US5713979A (en) * | 1992-05-14 | 1998-02-03 | Tsl Group Plc | Heat treatment facility for synthetic vitreous silica bodies |
US20030209540A1 (en) * | 2002-05-09 | 2003-11-13 | Girish Dahake | Induction furnace for heating a workpiece in an inert atmosphere or vacuum |
US20070128569A1 (en) * | 2005-12-07 | 2007-06-07 | Ajax Tocco Magnethermic Corporation | Furnace alignment system |
US8242420B2 (en) * | 2008-08-31 | 2012-08-14 | Inductotherm Corp. | Directional solidification of silicon by electric induction susceptor heating in a controlled environment |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106017071A (en) * | 2016-05-31 | 2016-10-12 | 成都西沃克真空科技有限公司 | Vacuum furnace |
CN106885466A (en) * | 2017-03-23 | 2017-06-23 | 合肥迅达电器有限公司 | A kind of middle frequency furnace of energy-conservation |
US11441235B2 (en) * | 2018-12-07 | 2022-09-13 | Showa Denko K.K. | Crystal growing apparatus and crucible having a main body portion and a low radiation portion |
US11453957B2 (en) * | 2018-12-07 | 2022-09-27 | Showa Denko K.K. | Crystal growing apparatus and crucible having a main body portion and a first portion having a radiation rate different from that of the main body portion |
WO2024033643A1 (en) * | 2022-08-10 | 2024-02-15 | Vacuum Furnace Engineering Ltd | A vacuum furnace device |
Also Published As
Publication number | Publication date |
---|---|
WO2014035490A3 (en) | 2015-06-18 |
WO2014035491A1 (en) | 2014-03-06 |
WO2014035480A1 (en) | 2014-03-06 |
WO2014035490A2 (en) | 2014-03-06 |
WO2014035492A1 (en) | 2014-03-06 |
US9657992B2 (en) | 2017-05-23 |
US20150247671A1 (en) | 2015-09-03 |
US20150226485A1 (en) | 2015-08-13 |
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