EP0248727A1 - Hochfrequenz-Induktionsofen - Google Patents

Hochfrequenz-Induktionsofen Download PDF

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Publication number
EP0248727A1
EP0248727A1 EP87401230A EP87401230A EP0248727A1 EP 0248727 A1 EP0248727 A1 EP 0248727A1 EP 87401230 A EP87401230 A EP 87401230A EP 87401230 A EP87401230 A EP 87401230A EP 0248727 A1 EP0248727 A1 EP 0248727A1
Authority
EP
European Patent Office
Prior art keywords
melting furnace
crucible
turn
furnace according
coil
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.)
Granted
Application number
EP87401230A
Other languages
English (en)
French (fr)
Other versions
EP0248727B1 (de
Inventor
Bruno Caillaut
René Perrier De la Bathie
Jacques Terrier
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.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
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 Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP0248727A1 publication Critical patent/EP0248727A1/de
Application granted granted Critical
Publication of EP0248727B1 publication Critical patent/EP0248727B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H05B6/24—Crucible furnaces
    • H05B6/28—Protective systems
    • 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
    • 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 specially adapted for crucible or pot furnaces
    • F27B14/10—Crucibles
    • 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
    • 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 specially adapted for crucible or pot furnaces
    • F27B2014/0837—Cooling arrangements

Definitions

  • the present invention relates to a melting furnace by electromagnetic induction by circulation of high frequency alternating current, usable in particular for the melting and transformation of refractory materials such as ceramic oxides, glass and chemical salts.
  • the principle of the induction furnace consists in passing an inductor through an alternating current; a magnetic field is then created inside this inductor where the charge is liquefied. Induced currents are then generated, which circulate inside this load and are converted into heat energy by the Joule effect, provided that the resistivity of the load is less than a value depending on the diameter of this load and the frequency considered.
  • refractory materials can be considered as insulating at ambient temperature, but their resistivity decreases beyond a temperature here called inducibility. In this case it is necessary to provide a heating means to ensure the initiation of the induction phenomenon.
  • the furnace can operate in continuous casting provided that it has suitable filling and emptying means.
  • the inductor may consist of a simple envelope of conductive metal, generally cylindrical in shape and interrupted only by a slot at the terminals of which the voltage taps arrive. The current therefore travels a full turn only around the load.
  • This design will be called monospire in what follows.
  • the inductor can also consist of a solenoid (multispire design), the current then flows through a propeller. - Whether monospire or multispire, the inductor can be isolated from the charge to be liquefied by a cooled or refractory wall (indirect induction mode).
  • multispire inductors are their high impedance, the inductance being proportional to the square of the number of turns as well as to the square of the diameter. It is then necessary to use crucibles of small diameter (in practice, not more than 35 cm for a winding with two turns), which poses problems of induction inside the load and on the other hand limits the surface heat exchange between the molten bath and the raw material added continuously.
  • Another disadvantage of monospires is linked to the risk of forming an electric arc between the voltage taps, as mentioned above. This results in a limitation of the potential differences with which one can work.
  • the present invention provides an improvement on existing solutions insofar as it combines the simplest design: monospire oven in self-crucible, with a device making it possible to guard against the risks of arcing which constitute the major problem of monospire.
  • the subject of the present invention is a melting furnace for induction refractory materials, the electrically conductive wall of which consists of a single cylindrical turn, the ends of which are connected to a source of high frequency alternating current, said turn forming both the inductor and the crucible proper and comprising means for cooling its surface, this furnace being characterized in that it comprises at least one cooled piece of elongated shape made of electrically conductive material, disposed along the slot delimited by the ends of the turn, maintained at a floating potential and electrically isolated from said turn.
  • the elongated piece which constitutes the essential means of the invention, thus fulfills a double function.
  • the space between the cooled part and the ends of the coil is filled with an electrical insulator which must withstand maximum temperatures of approximately 200 ° C. and can therefore be made of paper, plaster, epoxy resin or thin layer refractory cement.
  • the bottom of the crucible is made of a conductive material.
  • the coil is then electrically isolated from the bottom of the crucible by a refractory electrical insulator.
  • the conductive material constituting the bottom of the crucible is of the same nature as that of the coil.
  • the bottom of the crucible is made of an insulating material.
  • the lower part of the turn, adjacent to the bottom of the crucible is notched.
  • This arrangement in the case of a conductive crucible bottom allows, according to the invention, not to disturb the electromagnetic field in the lower part of the crucible by greatly reducing the coupling between the monospire and the bottom of the crucible.
  • This arrangement in the case of an insulating crucible bottom, makes it possible to limit the field of induction in the charge and thus prohibit fusion on contact with the refractory bottom.
  • the oven therefore generally comprises a turn 1 constituted, according to a preferred embodiment of the invention, of a curved sheet of an electrically conductive metal such as copper or aluminum, at the ends 2 from which an electrical circuit 3 introduces the alternating electrical current necessary for operation.
  • a turn 1 constituted, according to a preferred embodiment of the invention, of a curved sheet of an electrically conductive metal such as copper or aluminum, at the ends 2 from which an electrical circuit 3 introduces the alternating electrical current necessary for operation.
  • At least one elongated piece 5 of electrically conductive material maintained at a floating potential and electrically isolated from the coil 1 by a space which can optionally be filled with an insulator 6 disposed between the part 5 and the ends of the coil 1.
  • the part 5 is unique and makes it possible to halve the value of the tension between the two ends of the turn.
  • Each part 5 is subject to the action of the electromagnetic field and therefore traversed by induced heat-generating currents. It therefore essentially consists of a hollow envelope 7 inside which circulates a cooling fluid.
  • FIG. 2 indicates a possible configuration, according to which a metal tube 8 is introduced inside the envelope 7: the fluid enters through the metal tube 8 and rises along the envelope 7.
  • the insulator 6, which also seals the crucible, must withstand maximum temperatures of around 200 ° C. since the part 5 is cooled. It can be made of paper, plaster or epoxy resin or refractory cement in a thin layer for example.
  • the bottom 9 of the crucible can be made of refractory material.
  • the device shown in Figure 4, ensuring the emptying of the liquefied product then consists essentially of a cooled copper tube 18 by a few windings of a smaller copper tube 20 in which circulates a cooling fluid, the whole being embedded in the refractory material constituting the bottom 9 and closed by a plug 22 of copper itself cooled.
  • the bottom 9 can also be made, as is the case in FIG. 1, of the same conductive material as the turn 1, the emptying device then being limited to a hole bored in the bottom and closed by a cooled copper plug, as for the embodiment described in the previous paragraph. It is then necessary to provide electrical insulation between the bottom and the coil and to avoid an excessive modification of the lines of the electromagnetic field; this is why an insulating and refractory joint 10 separates the bottom and the turn, and moreover the part of the turn adjacent to the bottom is notched, which removes the part of the electromagnetic field which would have undergone coupling due to the presence of the bottom .
  • These notches 11 formed in the turn are sealed by an electrical insulator which seals the crucible. They are generally arranged periodically and their length is of the order of a tenth of the height of the turn.
  • the cooling of the walls of the crucible is carried out by means of small copper tubes 12 which are the seat of a forced circulation of fluid brought in and collected after use by two collectors 13 and 14 of larger diameters.
  • the tubes 12 are generally circumferential. Only the cutouts 15 limited by the notches are cooled by circulation of fluid in bent tubes 16 winding along the cutouts.
  • This oven can be adapted to continuous operation, the solid material being able to be introduced continuously and discharged in the form of liquid by overflow using a chute not shown here fixed in the upper part of the coil, as is described in the patent application French No. 8,302,328.
  • the advantage of the invention consists in that the part (s) 5 allow (s) to operate with a higher voltage current without fear of the formation of an electric arc between the ends of the coil 1 : this voltage can be doubled in the case of an oven comprising only one of these parts. It is then possible to work with a turn of diameter twice as large, making it possible to process products with higher resistivity, which implies a heat exchange surface four times greater.
  • the inductance and resistance of an inductor and therefore its impedance are proportional to the square of the number of turns.
  • the impedance of a monospire, four times lower than that of an inductor with two turns, also makes it possible not to change the diameter and to work at a frequency four times lower, which is equivalent from an energy point of view but allows the use of much simpler and more efficient AC transformers in some cases.
  • the material brought to the melting point is a borosilicate glass of the VR15F type sold by HPC.
  • the loading of raw powder is made continuously on the surface and the evacuation of the molten glass takes place by overflow through a chute formed in the upper part of the inductor.
  • Table 1 presents the main characteristics and the results of two tests carried out using an inductor monospire diameter 400 mm or 600 mm. For comparison, characteristics and results of a test carried out using an inductor two turns (diameter 300 mm) of the prior art, are given in the first column of this table.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Furnace Details (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • General Induction Heating (AREA)
EP87401230A 1986-06-03 1987-06-02 Hochfrequenz-Induktionsofen Expired - Lifetime EP0248727B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8607970 1986-06-03
FR8607970A FR2599482B1 (fr) 1986-06-03 1986-06-03 Four de fusion a induction haute frequence

Publications (2)

Publication Number Publication Date
EP0248727A1 true EP0248727A1 (de) 1987-12-09
EP0248727B1 EP0248727B1 (de) 1990-09-12

Family

ID=9335942

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87401230A Expired - Lifetime EP0248727B1 (de) 1986-06-03 1987-06-02 Hochfrequenz-Induktionsofen

Country Status (6)

Country Link
US (1) US4761528A (de)
EP (1) EP0248727B1 (de)
JP (1) JPH01118088A (de)
DE (1) DE3764871D1 (de)
ES (1) ES2017507B3 (de)
FR (1) FR2599482B1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU608785B2 (en) * 1986-12-04 1991-04-18 Flowserve Corporation Method for induction melting reactive metals and alloys
US5268925A (en) * 1991-03-01 1993-12-07 Degussa Aktiengesellschaft Method and apparatus for the semi-continuous melting and discharging of ceramic material in an induction melting furnace with singering crust crucible
FR2797440A1 (fr) 1999-08-13 2001-02-16 Cerdec Ag Procede de production de produits a base d'oxyde de zirconium cubique stabilise, produits obtenus par ce procede et leur utilisation
CN105758178A (zh) * 2016-05-12 2016-07-13 核工业理化工程研究院 整体式水冷铜坩埚

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3939017C2 (de) * 1988-12-15 1998-07-02 Blum Gmbh & Co E Induktiv beheizbare Vorrichtung
US5304767A (en) * 1992-11-13 1994-04-19 Gas Research Institute Low emission induction heating coil
US5461215A (en) * 1994-03-17 1995-10-24 Massachusetts Institute Of Technology Fluid cooled litz coil inductive heater and connector therefor
RU2137069C1 (ru) * 1998-05-12 1999-09-10 Акционерное общество открытого типа "Ракетно-космическая корпорация "Энергия" имени С.П.Королева" Гарнисажный тигель
US6727483B2 (en) 2001-08-27 2004-04-27 Illinois Tool Works Inc. Method and apparatus for delivery of induction heating to a workpiece
US8038931B1 (en) 2001-11-26 2011-10-18 Illinois Tool Works Inc. On-site induction heating apparatus
US6713737B1 (en) * 2001-11-26 2004-03-30 Illinois Tool Works Inc. System for reducing noise from a thermocouple in an induction heating system
US6956189B1 (en) 2001-11-26 2005-10-18 Illinois Tool Works Inc. Alarm and indication system for an on-site induction heating system
US7015439B1 (en) 2001-11-26 2006-03-21 Illinois Tool Works Inc. Method and system for control of on-site induction heating
US6911089B2 (en) 2002-11-01 2005-06-28 Illinois Tool Works Inc. System and method for coating a work piece
US20040084443A1 (en) * 2002-11-01 2004-05-06 Ulrich Mark A. Method and apparatus for induction heating of a wound core
US20050230379A1 (en) * 2004-04-20 2005-10-20 Vianney Martawibawa System and method for heating a workpiece during a welding operation
DE102006004637B4 (de) * 2006-01-31 2010-01-07 Schott Ag Induktiv beheizbarer Skulltiegel, Schmelzanlage und Verfahren zum kontinuierlichen Herstellen einer Glasschmelze
DE102008004739A1 (de) * 2008-01-16 2009-07-23 Schott Ag Verfahren und Vorrichtung zum Schmelzen oder Läutern von Glasschmelzen
DE102009033501B4 (de) * 2009-07-15 2016-07-21 Schott Ag Verfahren und Vorrichtung zum kontinuierlichen Schmelzen oder Läutern von Schmelzen
KR101218923B1 (ko) * 2010-09-15 2013-01-04 한국수력원자력 주식회사 유도코일과 용융로 일체형 유도가열식 저온용융로
JP6013467B2 (ja) * 2011-06-06 2016-10-25 ジーティーエイティー コーポレーションＧｔａｔ Ｃｏｒｐｏｒａｔｉｏｎ 結晶成長装置用の加熱部品
CN105043097A (zh) * 2014-06-23 2015-11-11 宁波新欣海天电炉有限公司 一种节能钢壳炉
CN109612272B (zh) * 2018-12-04 2020-10-16 山东迈科钨钼科技股份有限公司 一种基于余热洁净加热技术的高温硅钼棒熔炉
FR3092656B1 (fr) 2019-02-07 2021-03-19 Inst Polytechnique Grenoble Creuset froid
CN112113423B (zh) * 2020-09-07 2022-06-14 宁国市宏达电炉有限公司 用于感应加热炉的开放式炉架

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE697555C (de) * 1936-05-27 1940-10-17 Heraeus Vacuumschmelze Akt Ges Hochfrequenz-Induktionsofen
FR1430192A (fr) * 1964-12-29 1966-03-04 Electro Refractaire Four électrique à induction à haute fréquence
FR1430962A (fr) * 1964-12-29 1966-03-11 Electro Refractaire Procédé et appareil de fusion et solidification continues des réfractaires électrofondus
DE3316546C1 (de) * 1983-05-06 1984-04-26 Philips Patentverwaltung Gmbh, 2000 Hamburg Kalter Tiegel fuer das Erschmelzen und die Kristallisation nichtmetallischer anorganischer Verbindungen
FR2540982A1 (fr) * 1983-02-14 1984-08-17 Commissariat Energie Atomique Procede de preparation de materiaux ceramiques par fusion par induction a haute frequence

Family Cites Families (9)

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Publication number Priority date Publication date Assignee Title
US1975438A (en) * 1931-09-09 1934-10-02 Ugine Infra Magnetic muffle or other body and method of varying the magnetic transformation thereof
FR1492063A (fr) * 1966-04-05 1967-08-18 Commissariat Energie Atomique Perfectionnement aux fours électriques haute fréquence pour la fabrication en continu de réfractaires électrofondus
DE1802524B1 (de) * 1968-10-11 1970-06-04 Siemens Ag Vorrichtung zum tiegelfreien Zonenschmelzen eines kristallinen Stabes,insbesondere Halbleiterstabes
US3980853A (en) * 1973-07-12 1976-09-14 Daido Metal Company, Ltd. Inductive body for high frequency induction heating
JPS5826799B2 (ja) * 1977-09-10 1983-06-04 川崎製鉄株式会社 誘導加熱炉
SU748918A1 (ru) * 1977-12-26 1980-07-15 Московский Ордена Ленина Энергетический Институт Устройство дл индукционного нагрева
FR2497050A1 (fr) * 1980-12-23 1982-06-25 Saphymo Stel Dispositif de fusion par induction directe en cage froide avec confinement electromagnetique de la charge fondue
US4409451A (en) * 1981-08-31 1983-10-11 United Technologies Corporation Induction furnace having improved thermal profile
FR2531062A2 (fr) * 1981-11-06 1984-02-03 Saphymo Stel Dispositif de fusion par induction directe de substances dielectriques du genre verres ou emaux

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE697555C (de) * 1936-05-27 1940-10-17 Heraeus Vacuumschmelze Akt Ges Hochfrequenz-Induktionsofen
FR1430192A (fr) * 1964-12-29 1966-03-04 Electro Refractaire Four électrique à induction à haute fréquence
FR1430962A (fr) * 1964-12-29 1966-03-11 Electro Refractaire Procédé et appareil de fusion et solidification continues des réfractaires électrofondus
FR2540982A1 (fr) * 1983-02-14 1984-08-17 Commissariat Energie Atomique Procede de preparation de materiaux ceramiques par fusion par induction a haute frequence
DE3316546C1 (de) * 1983-05-06 1984-04-26 Philips Patentverwaltung Gmbh, 2000 Hamburg Kalter Tiegel fuer das Erschmelzen und die Kristallisation nichtmetallischer anorganischer Verbindungen

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU608785B2 (en) * 1986-12-04 1991-04-18 Flowserve Corporation Method for induction melting reactive metals and alloys
US5268925A (en) * 1991-03-01 1993-12-07 Degussa Aktiengesellschaft Method and apparatus for the semi-continuous melting and discharging of ceramic material in an induction melting furnace with singering crust crucible
US5430757A (en) * 1991-03-01 1995-07-04 Degussa Aktiengesellschaft Method and apparatus for the semi-continuous melting and discharging of ceramic material in an induction melting furnace with sintering crust crucible
US5526375A (en) * 1991-03-01 1996-06-11 Degussa Aktiengesellschaft Method and apparatus for the semi-continuous melting and discharging of ceramic material in an induction melting furnace with sintering crust crucible
FR2797440A1 (fr) 1999-08-13 2001-02-16 Cerdec Ag Procede de production de produits a base d'oxyde de zirconium cubique stabilise, produits obtenus par ce procede et leur utilisation
CN105758178A (zh) * 2016-05-12 2016-07-13 核工业理化工程研究院 整体式水冷铜坩埚
CN105758178B (zh) * 2016-05-12 2018-03-27 核工业理化工程研究院 整体式水冷铜坩埚

Also Published As

Publication number Publication date
US4761528A (en) 1988-08-02
FR2599482B1 (fr) 1988-07-29
DE3764871D1 (de) 1990-10-18
FR2599482A1 (fr) 1987-12-04
JPH01118088A (ja) 1989-05-10
EP0248727B1 (de) 1990-09-12
ES2017507B3 (es) 1991-02-16

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