US3180917A - Low frequency induction furnace - Google Patents

Low frequency induction furnace Download PDF

Info

Publication number
US3180917A
US3180917A US113880A US11388061A US3180917A US 3180917 A US3180917 A US 3180917A US 113880 A US113880 A US 113880A US 11388061 A US11388061 A US 11388061A US 3180917 A US3180917 A US 3180917A
Authority
US
United States
Prior art keywords
susceptor
inches
furnace
low frequency
present
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US113880A
Inventor
James P Morrison
John A Persson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Elkem Metals Co LP
Original Assignee
Union Carbide Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Union Carbide Corp filed Critical Union Carbide Corp
Priority to US113880A priority Critical patent/US3180917A/en
Application granted granted Critical
Publication of US3180917A publication Critical patent/US3180917A/en
Assigned to ELKEM METALS COMPANY, A NEW YORK GENERAL PARTNERSHIP reassignment ELKEM METALS COMPANY, A NEW YORK GENERAL PARTNERSHIP ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: UNION CARBIDE CORPORATION, A NY CORP.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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

Definitions

  • the present invention relates to a novel induction furnace. More particularly the present invention relates to a high temperature, induction furnace which is operable at low frequencies.
  • low frequency induction furnaces avoid many of e the disadvantages of high frequency operation, those low frequency induction furnaces which are presently known do not permit efficient operation at relatively high temperatures, i.e. up to about 2000 C.
  • FIGURE 1 shows a sectional elevational view of a furnace in accordance with the present invention.
  • FIGURE 2 shows a sectional view along 2-2 of FIG- URE 1 and
  • FIGURE 3 shows a graphical illustration of the relationship of relative susceptor resistance to susceptor wall thickness at 60 cycles.
  • an induction furnace which is adapted to be heated by low frequency electrical currents and which comprises a closed hollow graphite tube for containing the furnace charge.
  • a hollow cylindrical graphite susceptor 1 is shown mount ed on support 3 within an enclosing steel shell 5.
  • the wall thickness of the graphite susceptor of the present invention is relatively thin, e.g. between about 2 inches and 4 inches. This reduced Wall thickness, in addition to other benefits, provides increased furnace efficiency.
  • the design of the susceptor of the present invention is clescribed in more detail hereinbelow.
  • the susceptor 1 is of any suitable length, usually about 6 to feet, and is provided with adjoining carbon sleeves 7 and 9 and removable carbon plugs 11 and 12 which provide a means for the introduction and removal of the furnace charge.
  • the mean diameter of the susceptor is greater than about inches in order to obtain the increased efiiciency and and heat insulating layer 13 and when connected to a suitable low frequency source of electrical energy, such as transformers 17, inductor 15 causes thermal energy to be developed in the susceptor.
  • a hollow cylindrically shaped magnetic shunt 18 is arranged concentrically surrounding inductor l5 and is arranged to be at least co-extensive therewith.
  • the cylindrical magnetic shunt is comprised of closely adjacent electrically insulated steel strips 1h arranged in close proximity to the inductor and parallel to the longitudinal axis thereof.
  • Steel shell 5 which is shown to be water-cooled, encloses the furnace and is provided with suitable fittings 2i and 21 through which the charge can be introduced and withdrawn from the furnace.
  • Other materials such as copper and aluminum can be used in place of steel construction for shell 5.
  • inductor coil 15 is energized from the source of low frequency electrical energy, e.g. c.p.s., and the desired atmosphere is established and maintained within the furnace.
  • the magnetic field developed by the low frequency current flowing through inductor coil 15 is substantially contained in the space enclosed by magnetic shunt 18 and is intercepted by susceptor 1 to thereby provide a heat source for the furnac
  • the magnetic shunt 18, by substantially containing the magnetic flux developed by inductor 15, reduces heat losses and other adverse effects in the furnace structure and thereby improves the operating etliciency of the furnace. In the practice of the present invention it has been found that between 80 and 93 percent of the electrical energy supplied to the furnace is converted to thermal energy in the susceptor.
  • the graphite susceptor of the present invention is designed to have a particular wall thicnkess.
  • the graphite susceptor of the present invention is greater than about 20 inches in mean diameter having a wall thickness of between 2 inches and 4 inches.
  • the susceptor wall thickness is varied from about 4 inches for a diameter of about 20 inches to about 2 inches for a diameter of about 10 feet.
  • susceptor wall thickness is maintained at about 2 inches for diameter greater than 10 feet.
  • a susceptor of 50 inch mean diameter constructed in accordance with the present invention has a wall thickness of about 2.5 inches.
  • the susceptor of the present invention in addition to providing increased furnace operating capacity, also provides substantially increased furnace efficiency at high temperatures.
  • the graph of FIGURE 3 illustrates the improved efiiciency of a furnace in accordance with the present invention by showing the variation of relative susceptor resistance with susceptor thickness for a 50 inch diameter susceptor at 60 cycles.
  • the efficiency of an induction furnace increases with increasing susceptor resistance.
  • a 50 inch diameter graphite susceptor in accordance with the present invention having a thickness of 2.5 inches, has a relative resistance of about 10.8; susceptors of 50 inch diameter having different wall thicknesses, have lower values of relative resistance. That is, maximum furnace efficiency is obtained by providing a susceptor in accordance with the present invention while a susceptor wall thickness other than in accordance with the present invention will result in reduced furnace efficiency.
  • FIGURE 3 relates to graphite susceptor having a 50 inch diameter
  • similar plots can be established for various susceptor diameters, from a minimum of about 20 inches up to almost any conceivable upper limit. Susceptors below about 20 inches in diameter do not provide the increased furnace efficiency and improved furnace operations which are obtained with larger susceptors.
  • the furnace of the present invention has been designed particularly for use with 60 cycle alternating current in View of the ready availability of the electrical power in this form, it has been found that other relatively low frequency power sources can be employed.
  • the electrical efficiency is practically constant for frequencies between 30 and 180 cycles per second; with graphite susceptors having lesser diameters, a higher frequency (180 cycles) provides a somewhat greater efficiency than lower frequencies (30 cycles).
  • furnace of the present invention can be effectively employed in various metallurgical operation it is particularly suitable for the production of columbium, tantalum, vanadium, calcium metals, carbides and nitrides of the reactive metals, and boron carbide.
  • a specific furnace of the present invention provided an operating temperature of 2000 C. at a pressure of below about 50 to 200 microns. The efiiciency of the furnace was about 93 percent. In general, furnaces of the present invention having efficiencies greater than 90 percent can be readily provided.
  • a high temperature induction furnace comprising a tubular graphite susceptor greater than 20 inches in diameter and having a wall thickness of from 2 inches to 4 inches; coil means concentrically surrounding said susceptor being substantially coextensive therewith-and being adapted for connection to a low frequency source of electrical energy; a cylindrical magnetic shunt closely adjacent to and concentrically surrounding said coil means and being at least substantially coextensive therewith; a thermally insulating layer of carbon black disposed between said magnetic shunt and said susceptor; a metal shell enclosing said coil, susceptor and shunt means and being adapted to permit introduction of charge material into said susceptor, said shell being formed of a material selected from the group consisting of copper, aluminum and steel; means for controlling the atmosphere within the furnace; and a low frequency source of electrical energy connected to said coil means.
  • a high temperature induction furnace comprising a tubular graphite susceptor greater than 20 inches in diameter and having a wall thickness of from 2 inches to 4 inches; coil means concentrically surrounding said susceptor being substantially coextensive therewith and being adapted for connection to a low frequency source of electrical energy; a cylindrical magnetic shunt closely adjacent to and concentrically surrounding said coil means and being at least substantially coextensive therewith; a thermally insulating layer of carbon black disposed between said magnetic shunt and said susceptor; a steel shell enclosing said coil, susceptor and shunt means and being adapted to permit introduction of charge material into said susceptor; means for'reducing the pressure within said susceptor to below about 50 to 200 microns and for regulating the atmosphere within said susceptor; and a low frequency source of electrical energy connected to said coil means.

Description

April 27, 1965 J. P. MORRISON ETAL 3,180,917
LOW FREQUENCY INDUCTION FURNACE Filed llay 31, 1961 9 mmvroxs' JOHN A.PERSSON JAMES P. MORRISON E W m M G MATERIAL SUSCEPTOR DlA.-5OI rREQuENcY-ao WALL THICKNESS,INCHES M A T TORNE V United States Patent 3,180,917 LOW FREQUENCY INDUCTION FURNACE James P. Morrison, Sanborn, and John A. Persson, Buffalo, N .Y., assignors to Union Carbide Corporation, a corporation of New York Filed May 31, 1961, Ser. No. 113,880 2 Claims. (Cl. 13-27.)
The present invention relates to a novel induction furnace. More particularly the present invention relates to a high temperature, induction furnace which is operable at low frequencies.
While various types of induction furnaces are known to the art, most of these are energized by high frequency electrical current and for this reason are characterized by certain inherent disadvantages. A particular disadvantage is the necessity of providing accessory equipment which is capable of supplying the required high frequency electrical energy.
While low frequency induction furnaces avoid many of e the disadvantages of high frequency operation, those low frequency induction furnaces which are presently known do not permit efficient operation at relatively high temperatures, i.e. up to about 2000 C.
Accordingly, it is an object of the present invention to provide a high temperature induction furnace which is efficiently operable at low frequencies.
It is another object to provide a high temperature induction furnace operable at low frequencies having a graphite susceptor with a relatively small wall thicknessdiameter ratio and increased electrical eiiiciency.
These and other objects will be apparent from the following description and claims taken in conjunction with the drawing in which:
FIGURE 1 shows a sectional elevational view of a furnace in accordance with the present invention.
FIGURE 2 shows a sectional view along 2-2 of FIG- URE 1 and,
FIGURE 3 shows a graphical illustration of the relationship of relative susceptor resistance to susceptor wall thickness at 60 cycles.
In accordance with the present invention an induction furnace is provided which is adapted to be heated by low frequency electrical currents and which comprises a closed hollow graphite tube for containing the furnace charge.
With reference to FIGURES 1 and 2 of the drawing, a hollow cylindrical graphite susceptor 1 is shown mount ed on support 3 within an enclosing steel shell 5. The wall thickness of the graphite susceptor of the present invention is relatively thin, e.g. between about 2 inches and 4 inches. This reduced Wall thickness, in addition to other benefits, provides increased furnace efficiency. The design of the susceptor of the present invention is clescribed in more detail hereinbelow.
In the apparatus of the present invention the susceptor 1 is of any suitable length, usually about 6 to feet, and is provided with adjoining carbon sleeves 7 and 9 and removable carbon plugs 11 and 12 which provide a means for the introduction and removal of the furnace charge.
The mean diameter of the susceptor is greater than about inches in order to obtain the increased efiiciency and and heat insulating layer 13 and when connected to a suitable low frequency source of electrical energy, such as transformers 17, inductor 15 causes thermal energy to be developed in the susceptor. Additionally a hollow cylindrically shaped magnetic shunt 18 is arranged concentrically surrounding inductor l5 and is arranged to be at least co-extensive therewith. In a preferred form, the cylindrical magnetic shunt is comprised of closely adjacent electrically insulated steel strips 1h arranged in close proximity to the inductor and parallel to the longitudinal axis thereof.
Steel shell 5, which is shown to be water-cooled, encloses the furnace and is provided with suitable fittings 2i and 21 through which the charge can be introduced and withdrawn from the furnace. Other materials such as copper and aluminum can be used in place of steel construction for shell 5. A suitable pump 23, connected through conduit 25 to the susceptor l, is provided for controlling the atmosphere within the furnace, i.e. to evacuate the furnace to high vacuum conditions or, if desired, to provide an inert or reducin atmosphere within the furnace.
In the operation of the furnace of the present invention, a solid charge or melt is placed within the susceptor I; inductor coil 15 is energized from the source of low frequency electrical energy, e.g. c.p.s., and the desired atmosphere is established and maintained within the furnace. The magnetic field developed by the low frequency current flowing through inductor coil 15 is substantially contained in the space enclosed by magnetic shunt 18 and is intercepted by susceptor 1 to thereby provide a heat source for the furnac The magnetic shunt 18, by substantially containing the magnetic flux developed by inductor 15, reduces heat losses and other adverse effects in the furnace structure and thereby improves the operating etliciency of the furnace. In the practice of the present invention it has been found that between 80 and 93 percent of the electrical energy supplied to the furnace is converted to thermal energy in the susceptor.
As mentioned above, the graphite susceptor of the present invention is designed to have a particular wall thicnkess. The graphite susceptor of the present invention is greater than about 20 inches in mean diameter having a wall thickness of between 2 inches and 4 inches. To provide optimum furnace efficiency the susceptor wall thickness is varied from about 4 inches for a diameter of about 20 inches to about 2 inches for a diameter of about 10 feet. susceptor wall thickness is maintained at about 2 inches for diameter greater than 10 feet. A susceptor of 50 inch mean diameter constructed in accordance with the present invention has a wall thickness of about 2.5 inches.
The susceptor of the present invention, in addition to providing increased furnace operating capacity, also provides substantially increased furnace efficiency at high temperatures. The graph of FIGURE 3 illustrates the improved efiiciency of a furnace in accordance with the present invention by showing the variation of relative susceptor resistance with susceptor thickness for a 50 inch diameter susceptor at 60 cycles. The efficiency of an induction furnace increases with increasing susceptor resistance. With reference to FIGURE 3, it can be seen that a 50 inch diameter graphite susceptor in accordance with the present invention, having a thickness of 2.5 inches, has a relative resistance of about 10.8; susceptors of 50 inch diameter having different wall thicknesses, have lower values of relative resistance. That is, maximum furnace efficiency is obtained by providing a susceptor in accordance with the present invention while a susceptor wall thickness other than in accordance with the present invention will result in reduced furnace efficiency.
w Although the graph of FIGURE 3 relates to graphite susceptor having a 50 inch diameter, similar plots can be established for various susceptor diameters, from a minimum of about 20 inches up to almost any conceivable upper limit. Susceptors below about 20 inches in diameter do not provide the increased furnace efficiency and improved furnace operations which are obtained with larger susceptors.
Although the furnace of the present invention has been designed particularly for use with 60 cycle alternating current in View of the ready availability of the electrical power in this form, it has been found that other relatively low frequency power sources can be employed. For example, with graphite susceptors in accordance with the present invention having diameters of about thirty inches or more, the electrical efficiency is practically constant for frequencies between 30 and 180 cycles per second; with graphite susceptors having lesser diameters, a higher frequency (180 cycles) provides a somewhat greater efficiency than lower frequencies (30 cycles).
While the furnace of the present invention can be effectively employed in various metallurgical operation it is particularly suitable for the production of columbium, tantalum, vanadium, calcium metals, carbides and nitrides of the reactive metals, and boron carbide. A specific furnace of the present invention provided an operating temperature of 2000 C. at a pressure of below about 50 to 200 microns. The efiiciency of the furnace was about 93 percent. In general, furnaces of the present invention having efficiencies greater than 90 percent can be readily provided.
What is claimed is:
1. A high temperature induction furnace comprising a tubular graphite susceptor greater than 20 inches in diameter and having a wall thickness of from 2 inches to 4 inches; coil means concentrically surrounding said susceptor being substantially coextensive therewith-and being adapted for connection to a low frequency source of electrical energy; a cylindrical magnetic shunt closely adjacent to and concentrically surrounding said coil means and being at least substantially coextensive therewith; a thermally insulating layer of carbon black disposed between said magnetic shunt and said susceptor; a metal shell enclosing said coil, susceptor and shunt means and being adapted to permit introduction of charge material into said susceptor, said shell being formed of a material selected from the group consisting of copper, aluminum and steel; means for controlling the atmosphere within the furnace; and a low frequency source of electrical energy connected to said coil means.
2. A high temperature induction furnace comprising a tubular graphite susceptor greater than 20 inches in diameter and having a wall thickness of from 2 inches to 4 inches; coil means concentrically surrounding said susceptor being substantially coextensive therewith and being adapted for connection to a low frequency source of electrical energy; a cylindrical magnetic shunt closely adjacent to and concentrically surrounding said coil means and being at least substantially coextensive therewith; a thermally insulating layer of carbon black disposed between said magnetic shunt and said susceptor; a steel shell enclosing said coil, susceptor and shunt means and being adapted to permit introduction of charge material into said susceptor; means for'reducing the pressure within said susceptor to below about 50 to 200 microns and for regulating the atmosphere within said susceptor; and a low frequency source of electrical energy connected to said coil means.
References (Iited by the Examiner UNITED STATES PATENTS 2,729,556 1/56 Fontana 13-27 2,749,423 5/56 Bisterfeld 2l9-l0.43 3,912,553 11/59 Tudbury 2l9-10.49 3,036,888 5/62 Lowe 13--26 3,116,392 12/63 Morey 21940.49
FOREIGN PATENTS 451,484 9/48 Canada.
RICHARD M. WOOD, Primary Examiner.
MILTON HIRSHFIELD, ANTHONY BARTIS,
Examiner.

Claims (1)

  1. 2. A HIGH TEMPERATURE INDUCTION FURNACE COMPRISING A TUBULAR GRAPHITE SUSCEPTOR GREATER THAN 20 INCHES IN DIAMETER AND HAVING A WALL THIKCNESS OF FROM 2 INCHES TO 4 INCHES; COIL MEANS CONCENTRICALLY SURROUNDING SAID SUSCEPTOR BEING SUBSTANTIALLY COEXTENSIVE THEREWITH AND BEING ADAPTED FOR CONNECTION TO A LOW FREQUENCY SOURCE OF ELECTRICAL ENERGY; A CYLINDRICAL MAGNETIC SHUNT CLOSELY ADJACENT TO SAID CONCENTRICALLY SURROUDING SAID COIL MEANS AND BEING AT LEAST SUBSTANTIALLY COEXTENSIVE THEREWITH; A THERMALLY INSULATING LAYER OF CARBON BLACK DISPOSED BETWEEN SAID MAGNETIC SHUNT AND SAID SUSCEPTOR; A STEEL SHELL ENCLOSING SAID COIL, SUSCEPTOR AND SHUNT MEANS AND BEING ADAPTED TO PERMIT INTRODUCTION OF CHARGE MATERIAL INTO SAID SUSCEPTOR; MEANS FOR REDUCING THE PRESSURE WITHIN SAID SUSCEPTOR TO BELOW ABOUT 50 TO 200 MICRONS AND FOR REGULATING THE ATMOSPHERE WITHIN SAID SUSCEPTOR; AND A LOW FREQUENCY SOURCE OF ELECTRICAL ENERGY CONNECTED TO SAID COIL MEANS.
US113880A 1961-05-31 1961-05-31 Low frequency induction furnace Expired - Lifetime US3180917A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US113880A US3180917A (en) 1961-05-31 1961-05-31 Low frequency induction furnace

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US113880A US3180917A (en) 1961-05-31 1961-05-31 Low frequency induction furnace

Publications (1)

Publication Number Publication Date
US3180917A true US3180917A (en) 1965-04-27

Family

ID=22352073

Family Applications (1)

Application Number Title Priority Date Filing Date
US113880A Expired - Lifetime US3180917A (en) 1961-05-31 1961-05-31 Low frequency induction furnace

Country Status (1)

Country Link
US (1) US3180917A (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3980854A (en) * 1974-11-15 1976-09-14 Rca Corporation Graphite susceptor structure for inductively heating semiconductor wafers
US4039794A (en) * 1976-01-14 1977-08-02 Park-Ohio Industries, Inc. Apparatus and method for heating ferromagnetic abrasive shot
US4136276A (en) * 1976-01-20 1979-01-23 The Garrett Corporation Heat storage method and apparatus
US4242553A (en) * 1978-08-31 1980-12-30 Samuel Berkman Apparatus for use in the production of ribbon-shaped crystals from a silicon melt
US4347431A (en) * 1980-07-25 1982-08-31 Bell Telephone Laboratories, Inc. Diffusion furnace
US4499354A (en) * 1982-10-06 1985-02-12 General Instrument Corp. Susceptor for radiant absorption heater system
US5412185A (en) * 1993-11-29 1995-05-02 General Electric Company Induction heating of polymer matrix composites in an autoclave
WO2002065816A1 (en) * 2001-01-17 2002-08-22 Inductotherm Corp. Induction furnace for heating granules
US6693264B2 (en) * 2001-03-06 2004-02-17 Celes Vacuum and gas tight enclosure for induction heating system
US20070125769A1 (en) * 2005-12-07 2007-06-07 Ajax Tocco Magnethermic Corporation Method and apparatus for controlling furnace position in response to thermal expansion
US20100092666A1 (en) * 2006-12-25 2010-04-15 Tokyo Electron Limited Film deposition apparatus and film deposition method

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA451484A (en) * 1948-09-28 Federal Telephones And Radio Corporation H.f. heating apparatus for limited areas
US2729556A (en) * 1952-12-02 1956-01-03 Mars G Fontana Method for making pig iron or steel
US2749423A (en) * 1951-08-01 1956-06-05 Hartford Nat Bank & Trust Co Device for high-frequency heating
US3036888A (en) * 1959-12-29 1962-05-29 Norton Co Process for producing titanium nitride
US3116392A (en) * 1961-01-03 1963-12-31 Templeton Coal Company Apparatus for distilling liquids
US3912553A (en) * 1973-10-10 1975-10-14 Finkl & Sons Co Press forging die

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA451484A (en) * 1948-09-28 Federal Telephones And Radio Corporation H.f. heating apparatus for limited areas
US2749423A (en) * 1951-08-01 1956-06-05 Hartford Nat Bank & Trust Co Device for high-frequency heating
US2729556A (en) * 1952-12-02 1956-01-03 Mars G Fontana Method for making pig iron or steel
US3036888A (en) * 1959-12-29 1962-05-29 Norton Co Process for producing titanium nitride
US3116392A (en) * 1961-01-03 1963-12-31 Templeton Coal Company Apparatus for distilling liquids
US3912553A (en) * 1973-10-10 1975-10-14 Finkl & Sons Co Press forging die

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3980854A (en) * 1974-11-15 1976-09-14 Rca Corporation Graphite susceptor structure for inductively heating semiconductor wafers
US4039794A (en) * 1976-01-14 1977-08-02 Park-Ohio Industries, Inc. Apparatus and method for heating ferromagnetic abrasive shot
US4136276A (en) * 1976-01-20 1979-01-23 The Garrett Corporation Heat storage method and apparatus
US4242553A (en) * 1978-08-31 1980-12-30 Samuel Berkman Apparatus for use in the production of ribbon-shaped crystals from a silicon melt
US4347431A (en) * 1980-07-25 1982-08-31 Bell Telephone Laboratories, Inc. Diffusion furnace
US4499354A (en) * 1982-10-06 1985-02-12 General Instrument Corp. Susceptor for radiant absorption heater system
US5412185A (en) * 1993-11-29 1995-05-02 General Electric Company Induction heating of polymer matrix composites in an autoclave
WO2002065816A1 (en) * 2001-01-17 2002-08-22 Inductotherm Corp. Induction furnace for heating granules
US6693264B2 (en) * 2001-03-06 2004-02-17 Celes Vacuum and gas tight enclosure for induction heating system
US20070125769A1 (en) * 2005-12-07 2007-06-07 Ajax Tocco Magnethermic Corporation Method and apparatus for controlling furnace position in response to thermal expansion
US7745764B2 (en) * 2005-12-07 2010-06-29 Ajax Tocco Magnethermic Corporation Method and apparatus for controlling furnace position in response to thermal expansion
US20100092666A1 (en) * 2006-12-25 2010-04-15 Tokyo Electron Limited Film deposition apparatus and film deposition method
US8696814B2 (en) * 2006-12-25 2014-04-15 Tokyo Electron Limited Film deposition apparatus and film deposition method

Similar Documents

Publication Publication Date Title
US6690710B2 (en) High efficiency induction heating and melting systems
US3180917A (en) Low frequency induction furnace
US5109389A (en) Apparatus for generating an inductive heating field which interacts with metallic stock in a crucible
US3130292A (en) Arc torch apparatus for use in metal melting furnaces
RU2295206C2 (en) Multi-coil induction plasma burner with solid-bodied power source
US3194941A (en) High voltage arc plasma generator
US1975437A (en) Induction heated furnace
ES372628A1 (en) Apparatus for continuously melting of metal
US3223519A (en) Induction furnace
US3546348A (en) Non-consumable electrode vacuum arc furnaces for steel,zirconium,titanium and other metals and processes for working said metals
GB844570A (en) Improvements in or relating to apparatus for use in melting a zone of a rod of semi-conductor material
US2811623A (en) Method of heating metal billets by low frequency electrical power
US3860737A (en) Furnace and method for induction heating moving quantities of material
US3891828A (en) Graphite-lined inert gas arc heater
GB1593473A (en) Process and apparatus for heating gases or vapours
US3686421A (en) Unitized electride holder and arm for electric arc furnace electrodes or the like
US3628948A (en) Electric arc vacuum melting processes
US3100250A (en) Zone melting apparatus
US1971195A (en) Vacuum induction apparatus
US3396229A (en) Device for inductive heating and/or stirring
US6999496B2 (en) High efficiency induction heating and melting systems
US4247736A (en) Induction heater having a cryoresistive induction coil
US2408190A (en) Magnetic induction heating of thinwalled nonmagnetic metallic tubes
US3046320A (en) Induction furnace coil
US3549353A (en) Method and apparatus for melting reactive materials

Legal Events

Date Code Title Description
AS Assignment

Owner name: ELKEM METALS COMPANY, 270 PARK AVENUE, NEW YORK, N

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:UNION CARBIDE CORPORATION, A NY CORP.;REEL/FRAME:003882/0761

Effective date: 19810626

Owner name: ELKEM METALS COMPANY, A NEW YORK GENERAL PARTNERSH

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:UNION CARBIDE CORPORATION, A NY CORP.;REEL/FRAME:003882/0761

Effective date: 19810626