US20150226485A1

US20150226485A1 - System for gas purification in an induction vacuum furnace and method of making same

Info

Publication number: US20150226485A1
Application number: US14/422,289
Authority: US
Inventors: Gregory Alan Steinlage; Michael Louis Szugye; Ben David Poquette; Mark Andrew VanSumeren; Dale R. Wilcox; Peter M. Costantino; Timothy C. Tumia; Giovanni A. Dallicardillo
Original assignee: General Electric Co; GH Induction Atmostpheres LLC
Current assignee: General Electric Co; GH Induction Atmostpheres LLC
Priority date: 2012-08-30
Filing date: 2013-05-06
Publication date: 2015-08-13
Also published as: US20150247671A1; WO2014035490A3; US9657992B2; WO2014035491A1; WO2014035490A2; US20150230293A1; WO2014035480A1; WO2014035492A1

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.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This is a national stage application under 35 U.S.C. §371(c) of prior-filed, co-pending, PCT application serial number PCT/US2013/039737, filed on May 6, 2013, 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.

BACKGROUND OF THE INVENTION

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 cooling to a workpiece in a uniform fashion, so as to reduce thermal stress in the workpiece.
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.
With respect to the overall time required to perform the heating/cooling cycle, it is recognized that the cooling time is a very key factor in the overall cycle time. Thus, it is desirable to be able to reduce the cooling time that is necessary for cooling the workpiece to a desired temperature. As a means for decreasing the cooling time, some prior art systems introduce an inert cooling gas that helps to increase the rate of cooling of the workpiece. A typical vacuum furnace process includes backfilling with an inert gas during the cooling phase of the cycle using a blower linked to a heat removal assembly. The faster the gas moves, the more rapid the cool down. However, this rapid gas movement can disturb dirt, dust, oil vapor and other impurities in the system and can greatly impact components susceptible to such impurities. Such contamination can negatively affect the quality and cleanliness of the parts inside the chamber/hotzone. The higher the rate of movement of the gas, the higher the chances of part contamination.
It would therefore be desirable to have an induction furnace that provides for a decrease in the cooling time of the workpiece, while removing impurities during gas cooling of the workpiece.

BRIEF DESCRIPTION OF THE INVENTION

Embodiments of the invention overcome the aforementioned drawbacks by providing an induction furnace having a filter assembly incorporated therein that removes impurities during gas cooling of a workpiece heated by the furnace.
In accordance with one aspect of the invention, 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.
In accordance with another aspect of the invention, an induction furnace for cooling a workpiece includes 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, with the cooling system further 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.
In accordance with yet another aspect of the invention, a method of making an induction furnace includes 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.
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.

BRIEF DESCRIPTION OF THE 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 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 perspective view of a cooling manifold for use with the induction furnace of FIGS. 3 and 4.

FIG. 7 is a block schematic diagram of an induction furnace according to another embodiment of the invention.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, the major components of an induction furnace 100 are shown. Induction furnace 100 includes an induction heating system 102 inside a chamber 104. Induction heating system 102 includes an insulation cylinder 106 having a side wall 108, a top or first cover 110 for sealing one end of cylinder 106, and a base or second cover 112 for sealing the second end of cylinder 106. Induction heating system 102 includes a coil 114 and a power supply (not shown) that provides an alternating current that flows through coil 114 during a heating cycle. Coil 114 is wound to form a helical shape within chamber 104 about insulation cylinder 106 as shown in FIG. 1.
Contained within insulation cylinder 106 is a susceptor 116 that is susceptible to induction heating. That is, when an alternating current flows through coil 114, an alternating magnetic field is generated that induces eddy currents and other effects in susceptor 116 that cause the susceptor 116 to heat. The thermal energy that radiates from susceptor 116 is used to heat a workpiece 118. Susceptor 116 is shown as being cylindrical, but other shapes can be used. Susceptor 116 is made of any material susceptible to induction heating, such as, for example, graphite, molybdenum, steel, and tungsten. Susceptor 116 is arranged within insulation cylinder 106 in chamber 104. Insulation cylinder 106 is made from an insulative material that is not susceptible to induction heating such as, for example, fused quartz.
Susceptor 116 includes a side wall 120, a first cover 122 for sealing one end, and a second cover 124 for sealing the other end. A tray 126 for supporting workpiece 118 to be heated is connected to second cover 124 of susceptor 116. Although susceptor 116 is shown as having closed ends, this need not be the case. For example, the susceptor 116 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 110 of cylinder 106 is coupled to chamber 104 via one or more posts 128, which in an embodiment, is constructed of a ceramic material. First cover 122 of susceptor 116 is coupled to first cover 110 via one or more additional posts 130.
FIG. 1 illustrates induction heating system 102 in a raised or heating position where workpiece 118 is positioned within susceptor 116 and is ready for heating according to induction furnace principles as described above. As shown in FIG. 2, induction heating system 102 is in a lowered position where access to workpiece 118 through a door 132 of chamber 104 is possible. Induction furnace 100 also includes a vacuum pump 134 for creating a vacuum within the chamber 104. Door 132 forms a hermetic seal when closed such that a vacuum created by vacuum pump 134 in an interior volume of chamber 104 is hermetically isolated from an ambient environment outside chamber 104.
In operation of induction furnace 102, the workpiece 118 is in a raised or heating position, i.e., within in a “heating zone” 136 defined by susceptor 116, when a heating operation is being undertaken. The workpiece 118 is then moved to the lowered or cooling position, i.e., within in a “cooling zone” 138 outside of the susceptor 116, when a cooling operation is being undertaken. Moving workpiece 118 to the cooling zone 138 after completion of the heating of workpiece 118 allows for a reduction in the primary overall furnace cycle time. That is, the time required for cooling workpiece 118 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 136 and into the cool zone 138 of the vacuum chamber 104.
According to an exemplary embodiment of the invention, induction furnace 102 is constructed so as to facilitate movement of the workpiece 118 between the heating zone 136 and the cooling zone 138 while maintaining a desired vacuum pressure within chamber 104, and is further constructed to include elements to enhance cooling of the workpiece 118. Referring now to FIGS. 3 and 4, induction furnace 102 is shown as including a cooling system 140 for cooling chamber 104 after the workpiece 118 has been heated as desired. Cooling system 140 can include a heat exchanger 142, a blower 144, and a filter assembly 145. Hot gas within the chamber 104 is drawn into the heat exchanger 142 and is exchanged with cooler gas, and the cooler gas is blown back into chamber 104 by blower 144.
After completion of a heating of workpiece 118, the second cover 124 and tray 126 are dropped using a vacuum-sealed bellows system 146 attached to second cover 112. Bellows system 146 includes a pair of vacuum-sealed bellows 148, 150 attached to respective coupling device 152, 154 that are coupled to chamber 104. A pair of cover members or supports 157, 159 are coupled to second cover 112 and pass through coupling devices 152, 154 to couple to bellows 148, 150 as illustrated. In this manner, bellows 148, 150 and coupling devices 152, 154 surround or encircle coupling devices 152, 154. According to another embodiment, cover supports 157, 159 may be directly coupled to a plate 156, which is also coupled to bellows 148, 150. A linear actuator 158 such as a piston is coupled to chamber 104 external to its interior volume and is coupled to bellows 148, 150 via plate 156. Embodiments of the invention contemplate that linear actuator 158 may be a pneumatic or hydraulic piston, an electro-mechanical piston, a manual actuator, or the like. The interior volumes of bellows 148, 150 and coupling devices 152, 154 are fluidly coupled to the interior volume of chamber 104. In this manner, movement of linear actuator 158 from the outside of chamber 104 allows the atmosphere and pressure inside chamber 104 to be maintained when plate 156 is moved either away from or toward chamber 104. That is, while plate 156 is being moved away from or toward chamber 104, bellows 148, 150 expand or contract accordingly to maintain a separation of the inside of chamber 104 from the volume or the outside environment. Thus, workpiece 118 can be lowered from heating zone 136 to cooling zone 138 while being hermetically sealed from the outside of chamber 104.
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 118 is dropped into the cool section 138 after the part has cooled to approximately 1200° C. This effectively opens the insulated hot zone 136 and allows the cooling gas to pass across the heated parts 118. Once the workpiece 118 drops out of the hot zone 136, the workpiece 118 experiences improved radiative and convective cooling. The area of the cooling zone 138 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 136, and faster cycle times can be met.
The filter assembly 145 is configured to hold a vacuum-compatible filtering device 147 and provide ultrahigh temperature induction vacuum gas purification to the cooling system. As used herein, the term “filtering” is understood to mean that the device 147 is capable of and constructed to remove any of a number of desired impurities from the gas flowing through the cooling system, including (but not limited to) particulate matter, organics, oxygen, and/or other desired substances. For example, filtering device 147 could be configured as a charcoal filter to remove organics or a heated titanium mesh filter to remove oxygen. Filter assembly 145 is designed to allow filtering of the gas within chamber 104 while not impeding the function and cooling rate of the furnace system. The geometric design of filter assembly 145 is variable to allow for feasibility to enable high volume flow and/or high temperature filtering capability for the design and operating conditions for induction furnace 100. In addition, while filter assembly 145 is illustrated as being downstream of heat exchanger 142 and upstream of blower 144, embodiments of the invention contemplate coupling filter assembly 145 anywhere within system 140. That is, filter assembly 145 may instead be positioned upstream of heat exchanger 142 or downstream of blower 144, for example. In an embodiment where the filter assembly 145 is positioned upstream of heat exchanger 142, the filter assembly 145 may be positioned just inside of chamber 104 (i.e., on an exterior wall of the chamber 104)—rather than external to the chamber as is shown in FIGS. 3 and 4.
Filter assembly 145 includes a housing 149 that may be customized or may be a housing generally available in the industry. Examples of industry-available housings include housings for bag house systems, factory automation, food processing, glass and ceramic processes, medical systems, vacuum furnaces and packaging, vacuum pumps (rotary vane, screw compressors, and piston pumps), and central vacuum systems.
According to one embodiment, filtering device may be in the form of a particle filter 147 that is an industrial filter generally available in the industry that provides various particle size filtrations. Alternatively, the particle filter 147 may be a customized filter optimized for use in the cooling process for a particular workpiece 118. For example, the material for particle filter 147 may be selected based on a number of considerations, including chemical compatibility, outgassing, flow rate, structural stability, friability, temperature resistance, cost, and particulate capture efficiency. In one example, the filter material may be metallic wool (e.g., stainless steel wool). Other filter materials, however, are contemplated.
Filter assembly 145 is positioned, together with heat exchanger 142 and blower 144, outside the internal volume of chamber 104 in the ambient environment to allow access thereto for maintenance and other reasons. In this manner, filter assembly 145 may be more easily accessible than if it is positioned within chamber 104.
Referring now to FIG. 5, and with continued reference to the furnace of FIGS. 3 and 4, a technique 160 for heating and cooling a workpiece is illustrated according to an embodiment of the invention. As illustrated in FIG. 5, certain steps in the technique 160 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. These optional steps in technique 160 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.
As shown in FIG. 5, the technique begins at STEP 162 with loading of a workpiece 118 into the furnace 100, such as by way of door 132, with the piece being positioned on tray 126 when it is in a lowered position. The furnace door 132 is then closed, and the technique continues at STEP 164, where the interior of the furnace 100 is brought to a high vacuum, such as a 10⁻⁷vacuum pressure, by operation of vacuum pump 134. The workpiece 118 is then raised into the upper hot zone chamber 136 formed by insulating cylinder 106 and susceptor 116 at STEP 166. At STEP 168, the workpiece 118 is flushed with argon, and the interior of the furnace 100 is subsequently brought again to a high vacuum. The workpiece then begins to be heated at STEP 170, with an inert gas (e.g., nitrogen) then being introduced at partial pressure at STEP 172. The workpiece 118 is heated to 200-600° C. with the flowing inert gas to expedite removal of off-gassing, and the technique then continues at STEP 174 with the furnace chamber again being returned to a high vacuum via vacuum pump 134 and heated to a desired processing temperature. A material for coating the workpiece is then introduced if desired at STEP 176
The workpiece is begun to cool inside the vacuum at STEP 178. 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 the heating zone 136 and into the cooling zone 138 after the threshold has been met using the vacuum sealed bellows system 146 at STEP 180. In this manner, the vacuum pressure created inside the furnace may be maintained when moving the workpiece to the cooling zone 138. A quenching gas such as helium, argon, or nitrogen is then injected at STEP 182, with the gas being injected at atmospheric pressure according to one embodiment.
According to various embodiments, gas may be injected at STEP 182 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 136 into the cool section 138 of the vacuum chamber 104. Thus, the process of injecting gas at STEP 182 can incorporate a repositioning of the workpiece down into the cooling zone 138 outside of susceptor 116 by lowering hot zone tray 126. As set forth above, the lowering of the workpiece 118 down into the cooling zone 138 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 workpiece 118 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 118 when it is located in the cooling zone 138. By selectively positioning the workpiece 118 in the hot zone 136 and the cooling zone 138, the cooling time of the workpiece can be reduced greatly and faster cycle times can be met.
Since particles in chamber 104 may be disturbed and/or stirred by passing the cooling gas across the heated workpiece 118 when it is located in the cooling zone 138, filter assembly 145 acts to filter and remove such contaminants from the circulating gas so that workpiece 118 can be cooled by the gas having all or a majority of the contaminants removed therefrom.
It is recognized that temperature uniformity within the workpiece 118 is very important during the heating and cooling of the workpiece and that, during the cooling process, the workpiece can develop thermal stress. The stress is greatly increased as the temperature difference across the workpiece grows, with the stress in the material thereof potentially causing premature failure or changes in geometry due to warpage. In applying cooling gas to the workpiece 118, such as at STEP 182 of technique 160, a typical vacuum furnace has a single port for gas entry, such that the side of the workpiece placed next to the location that the gas enters the hot zone will cool very quickly compared to the side that is shielded from the gas. This thermal mismatch is a source of thermal stress.
Therefore, according to one embodiment of the invention, a cooling manifold or ring 184 with multiple equally spaced ports on the gas feed side is implemented in cooling zone 138 to drive uniform gas cooling. As shown in FIGS. 3, 4 and 6, the cooling manifold 184 is a cylindrically shaped member that is positioned about the cooling zone 138. A hollow interior volume of the cooling manifold 184 is defined by inner and outer walls 186, 188 along with top and bottom walls 190, 192. An inlet 194 is formed on one side of cooling manifold 184 to provide a supply of gas into the interior volume thereof, with the inlet 194 having a tubing or piping 196 connected thereto that provides cooling gas from an external source, such as the blower 144. To maintain structural integrity and non-friability (i.e., durability), the cooling manifold 184 may be manufactured from a material that is vacuum and temperature compatible.
A plurality of gas ports 198 are formed in inner wall 186, with the gas ports being formed at a plurality of locations in the inner wall. According to an exemplary embodiment of the invention, the ports 198 are spaced around the entire circumference of the inner wall 186, with the spacing of the ports being uniform. The exact number of ports 198 and the angular spacing therebetween is system and workload specific, with the goal of maximizing cooling uniformity. According to various embodiments of the invention, the gas ports 198 may be static holes or be louvers, for example. In the embodiment of cooling manifold 184 illustrated in FIG. 6, the gas ports 198 are constructed as louvers that are independently operable and selectively controlled such that desired louvers can be opened and others left in a closed position. For example, louvers opposite the inlet 194 and blower 144 may be closed to improve the cooling process. The desired gas flow rate through gas ports 198 can also be controlled, with the flow rate desirably being as large as possible, up to any limits imposed by the system or workpiece (i.e., a fragile workpiece may demand reduced flow), such that the cooling time of the workpiece 118 can be minimized.
While cooling manifold 184 is shown in FIG. 6 as being constructed as a cylindrical cooling ring, it is recognized that other constructions of the cooling manifold are envisioned and considered to be within the scope of the invention. For example, cooling manifold 184 could be constructed to have a horseshoe shape, hexagon shape, or other desired shape determined to fit the requirements of cooling of a specific workpiece. Additionally, rather than the wall structure of the cooling manifold having defined inner and outer walls and top and bottom walls, it is recognized that the cooling manifold could have a tube-like construction with no defined walls, but with a pipe-like structure being used to form the cooling manifold.
Referring now to FIG. 7, an induction furnace 200 is shown according to another embodiment of the invention. The induction furnace 200 is constructed as a vacuum furnace in which the workpiece is kept in a set position, without any sort of linear actuator (e.g., linear actuator 156 in FIGS. 3-4) to move the workpiece between separate heating and cooling positions, and thus induction furnace 200 also does not include an insulating cylinder or susceptor (e.g., insulating cylinder 106 or susceptor 116 in FIGS. 1-4). A cooling system 140 for cooling chamber 104 after the workpiece 118 has been heated is provided in induction furnace 200 and includes a heat exchanger 142, a blower 144, and a filter assembly 145, with the filter assembly desirably being configured/constructed as described above with respect to FIGS. 4 and 5. In operation, hot gas within the chamber 104 is drawn into the heat exchanger 142 and is exchanged with cooler gas, and the cooler gas is blown through filter assembly 145 and back into chamber 104 by blower 144, such as through a cooling manifold 184, although no cooling manifold is required. In the embodiment of FIG. 7, cooling manifold 184 is formed of a non-electrically conductive material (e.g., glass manifold), such that the cooling manifold is not inductively heated when a current is provided to induction coil 114.
Therefore, according to one embodiment of the invention, 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.
According to another embodiment of the invention, an induction furnace for cooling a workpiece includes 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, with the cooling system further 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.
According to yet another embodiment of the invention, a method of making an induction furnace includes 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.
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

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.