EP0020215B1 - Induktionswiedererwärmungsofen mit Wanderfeld - Google Patents

Induktionswiedererwärmungsofen mit Wanderfeld Download PDF

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Publication number
EP0020215B1
EP0020215B1 EP80400644A EP80400644A EP0020215B1 EP 0020215 B1 EP0020215 B1 EP 0020215B1 EP 80400644 A EP80400644 A EP 80400644A EP 80400644 A EP80400644 A EP 80400644A EP 0020215 B1 EP0020215 B1 EP 0020215B1
Authority
EP
European Patent Office
Prior art keywords
inductor
tubes
cooling
screen
furnace
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
Application number
EP80400644A
Other languages
English (en)
French (fr)
Other versions
EP0020215A1 (de
Inventor
Jean Delassus
Jacques Michelet
Bertrand De Lamberterie
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.)
Institut de Recherches de la Siderurgie Francaise IRSID
Original Assignee
Institut de Recherches de la Siderurgie Francaise IRSID
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 Institut de Recherches de la Siderurgie Francaise IRSID filed Critical Institut de Recherches de la Siderurgie Francaise IRSID
Publication of EP0020215A1 publication Critical patent/EP0020215A1/de
Application granted granted Critical
Publication of EP0020215B1 publication Critical patent/EP0020215B1/de
Expired 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
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/101—Induction heating apparatus, other than furnaces, for specific applications for local heating of metal pieces
    • H05B6/103—Induction heating apparatus, other than furnaces, for specific applications for local heating of metal pieces multiple metal pieces successively being moved close to the inductor
    • H05B6/104—Induction heating apparatus, other than furnaces, for specific applications for local heating of metal pieces multiple metal pieces successively being moved close to the inductor metal pieces being elongated like wires or bands
    • 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

Definitions

  • the present invention relates to an electric furnace with variable geometry intended for the induction heating of metallic products, in particular of large format, such as steel slabs which are placed on edge inside the furnace.
  • the heating device is a flat inductor with a sliding magnetic field, constituting the essential element of at least one large movable side wall of the oven.
  • This inductor comprises electrical conductors with bars which are housed in notches formed in a magnetic yoke on the face facing the interior of the oven and hereinafter referred to as "active face of the inductor".
  • One of the essential requirements is to ensure that the inductor is kept at an acceptable temperature level in the face of the thermal load originating from both the internal heating and the radiation of the product in the oven.
  • the thermal protection of the inductor is obtained by the combined action of a refractory coating equipping the active face of the inductor and a circulation of cooling fluid in the notches.
  • the thermal protection of the inductor is supplemented by a circulation of cooling fluid in channels parallel to the bars, placed at the head of notches.
  • certain difficulties may appear: difficulties of practical realization first of all, because it is not simple to set up such channels in the notches of the cylinder head; mechanical strength difficulties then due to phenomena of vibration of the inductor during the passage of the alternating current; electrical difficulties finally because these channels, arranged parallel to the busbars, can become the seat of parasitic eddy currents.
  • the object of the present invention is to improve the cooling efficiency of the inductor without having the aforementioned drawbacks.
  • the subject of the invention is an electric oven with variable dimensions of the heating enclosure and intended for the induction heating of metallic products, in particular of large format, such as steel slabs, arranged on edge at the edge.
  • the heating device is a plane inductor with a sliding magnetic field constituting at least one large movable side wall of the oven and equipped on its active face with a refractory lining
  • oven comprising means for cooling the inductor with internal circulation of a cooling fluid and characterized in that these means consist of an independent cooling screen, interposed between the active face of the inductor and the refractory lining and having a composite structure so as to present a plurality of electrical discontinuities each extending in a direction transverse to that of the conductors of the primary current in the inductor, and consecutive one of the other res in the direction of said conductors.
  • the present invention therefore consists in replacing the cooling channels incorporated in the magnetic yoke of the inductor by a cooling screen independent of the yoke, masking the active face of the inductor and sandwiched between the latter and the refractory lining.
  • a characteristic of the invention consists in providing this screen with a composite structure so to present electrical discontinuities one after the other in a direction parallel to the conductor bars of the inductor.
  • One possible technology consists in making the walls of the screen in alternating metal and non-metallic strips, oriented perpendicular ment to the busbars, the inductor.
  • cooling screen consists of metal tubes placed side by side in close proximity but without contact with each other, so as to provide between two consecutive tubes a electrical insulation space, said tubes being oriented perpendicular to the busbars.
  • this screen can be produced from elementary units which are assembled on the oven. This solution allows prefabricating standard size units, the number of which will be used will depend on the size of the oven intended to receive them.
  • FIGs 1 and 2 there is shown at 1 a steel slab arranged on edge inside the heating oven 2 by means of a support base 3.
  • the large side walls 4 placed opposite the large faces of the slab are movable in translation on a raceway by means of wheels6.
  • the movements of the walls are controlled by jacks shown in 7, 7 '.
  • the closing of the heating enclosure is completed laterally by two small refractory partitions 8, at the upper part by a refractory cover 9 and the sealing of the enclosure at its lower part is ensured by compression of an elastic seal 10 under the action of the base 3.
  • the large side walls 4 of the furnace are essentially constituted by a plane electromagnetic inductor 11.
  • This is formed by a magnetic yoke 12, laminated vertically and having, on the side of the slab, horizontal notches in which bars 13 of the Roebel type are housed for the passage of electric current.
  • These bars are connected in a known manner to a polyphase power supply, not shown (for example three-phase), so as to generate in the enclosure of the furnace a mobile magnetic field, sliding vertically.
  • a polyphase power supply not shown (for example three-phase)
  • the conductive bars 13 are more visible in FIG. 2 where their curved ends 14 are also shown more generally called “coil heads” and allowing the series connection of the bars connected to the same phase of the power supply.
  • the inductor is equipped on its active face, designated at 18, with a refractory lining 19 with interposition between the two, with a cooling screen 20 of composite structure according to the invention, and of which a shape preferred embodiment but not limiting is described in more detail below.
  • the screen 20 is constituted by a plurality of parallel metal tubes 21 arranged side by side in close proximity but without mutual contact so as to define between them spaces of electrical insulation 22. These tubes 21 are oriented perpendicular to the corrugated bars - Trices 13, that is to say vertically in the example described. To give the assembly additional rigidity, the spaces 22 are preferably filled with an appropriate material, insulating from heat and electricity, for example a material available commercially under the designation of "Syndanio", composed a mixture of mineral stone and asbestos agglomerated under high pressure.
  • the screen 20 is part of a cooling circuit (not shown) to allow internal circulation of a cooling fluid, for example water, and which will be considered as such in the following.
  • a cooling fluid for example water
  • the screen 20 is produced by assembling 'identical elementary cooling units 23, a copy of which is clearly visible in FIGS. 3 and 4.
  • each unit 23 comprises an inlet pipe 24 and an outlet pipe 25 for the internal circulation of the cooling water.
  • the tubes 21 belonging to a same unit 23 can be mounted in parallel or preferably in series as is the case in FIG. 3.
  • the unit 23 constitutes a cooling coil in which the water circulates successively in each of the tubes 21 which allows a better distribution of the absorption of heat flux
  • the tubes communicate with each other at their end by means of two transverse conduits, respectively upper 26 and lower 27.
  • This particular technology has the advantage of being able to pass from a parallel mounting of the tubes to a mounting in series without requiring significant modifications.
  • closures can be carried out simply, as shown in the figure by means of pellets 28 placed in the conduits after having made in the latter semi-annular cutouts 29 in the appropriate places.
  • inlet and outlet pipes 24 and 25 are located on the same side of the screen, which has the advantage of greater practical simplicity in terms of the overall architecture of the oven.
  • the non-magnetic stainless steel tubes 21 have an external diameter of 15 mm and a thickness of 2 mm. On this subject, it is preferable, for electromagnetic reasons, to choose the smallest possible tube thickness, compatible with the requirements of mechanical strength of the screen, which can be improved, as we have seen, by placing in the spaces 22 of the insulating shims.
  • These spaces 22 are of small width: 2 mm in the example described. This value can be further reduced, the only condition being that the tubes are not in contact with each other in order to avoid electrical continuity in the transverse direction.
  • the length of the tubes is preferably at least equal to the height of the active region of the inductor. This arrangement has the additional advantage of placing the transverse lines 26 and 27 outside the air gap and thus preventing them from becoming the seat of eddy currents.
  • the units 23 are fixed to the furnace using two identical flanges extending the screen vertically on either side.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Furnace Details (AREA)
  • General Induction Heating (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)

Claims (6)

1. Elektrischer Ofen mit veränderlichen Abmessungen der Heizummantelung zur induktiven Aufheizung von senkrecht stehenden metallischen Körpern, bei welchem die Heizvorrichtung ein ebener Induktor (11) mit einem gleitenden Magnetfeld ist, der mindestens eine bewegliche Seitenwand (4) des Ofens bildet, auf seiner wirksamen Seite (18) eine feuerfeste Auskleidung (19) aufweist und mittels von einem Kühlfluid durchströmter Kühlmittel gekühlt wird, dadurch gekennzeichnet, daß die Kühlmittel einen am Ofen ohne Verbindung mit dem Induktor (11) angebrachten Kühlschirm (20) bilden, der zwischen der wirksamen Seite (18) des Induktors (11) und der feuerfesten Auskleidung (19) angeordnet ist und eine Vielzahl von elektrischen Unterbrechungen (22) aufweist, die sich einzeln in einer zu den Primärstromleitern (13) des Induktors (11) senkrechten Richtung erstrecken und eine in Richtung der Primärstromleiter (13) sich erstreckende Folge bilden.
2. Elektrischer Ofen nach Anspruch 1, dadurch gekennzeichnet, daß der Kühlschirm (20) durch eine Vielzahl von in gegenseitigem Abstand parallel nebeneinander angeordneten, elektrisch isolierende Zwischenräume bildenden metallischen Rohren (21) gebildet wird, die sich senkrecht zur Richtung des Primärstroms des Induktors (11) erstrecken.
3. Elektrischer Ofen nach Anspruch 2, dadurch gekennzeichnet, daß der Kühlschirm (20) durch Zusammenbau mehrerer identischer Elementareinheiten (23) gebildet wird, von denen jede eine Mehrzahl von Rohren (21) aufweist.
4. Elektrischer Ofen nach Anspruch 3, dadurch gekennzeichnet, daß die eine Elementareinheit (23) bildenden Rohre (21) unter Bildung einer Kühlschlange miteinander verbunden sind und die Elementareinheiten (23) parallel zueinander angeordnet sind.
5. Elektrischer Ofen nach Anspruch 4, dadurch gekennzeichnet, daß die Rohre (21) an ihren Enden in Serie miteinander verbunden sind.
6. Elektrischer Ofen nach Anspruch 2, dadurch gekennzeichnet, daß die elektrisch isolierenden Zwischenräume (22) von einem elektrisch isolierenden Stoff erfüllt sind, der dem Kühlschirm (20) die Eigenschaft eines mechanisch steifen Körpers verleiht.
EP80400644A 1979-05-23 1980-05-12 Induktionswiedererwärmungsofen mit Wanderfeld Expired EP0020215B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7913428 1979-05-23
FR7913428A FR2457619A2 (fr) 1979-05-23 1979-05-23 Four de rechauffage a induction a champ glissant

Publications (2)

Publication Number Publication Date
EP0020215A1 EP0020215A1 (de) 1980-12-10
EP0020215B1 true EP0020215B1 (de) 1983-07-13

Family

ID=9225888

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80400644A Expired EP0020215B1 (de) 1979-05-23 1980-05-12 Induktionswiedererwärmungsofen mit Wanderfeld

Country Status (8)

Country Link
US (1) US4339625A (de)
EP (1) EP0020215B1 (de)
JP (1) JPS55155489A (de)
CA (1) CA1140192A (de)
CH (1) CH635921A5 (de)
DE (1) DE3064098D1 (de)
DK (1) DK218980A (de)
FR (1) FR2457619A2 (de)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8204438A (nl) * 1982-11-16 1984-06-18 Philips Nv Werkwijze en inrichting voor de continue vervaardiging van langgerekte lichamen uitgaande van een ongesmolten uitgangsmateriaal.
FR2630612B1 (fr) * 1988-04-26 1996-05-24 Siderurgie Fse Inst Rech Dispositif de protection des poles d'inducteurs et inducteur pourvu de ce dispositif
DE3934208C2 (de) * 1989-10-13 1994-02-17 Kuesters Eduard Maschf Spulenkörper für die induktive Beheizung von Walzen
US5550353A (en) * 1990-01-31 1996-08-27 Inductotherm Corp. Induction heating coil assembly for prevent of circulating current in induction heating lines for continuous-cast products
US5257281A (en) * 1990-01-31 1993-10-26 Inductotherm Corp. Induction heating apparatus and method
US5272720A (en) * 1990-01-31 1993-12-21 Inductotherm Corp. Induction heating apparatus and method
JP2722794B2 (ja) * 1990-08-01 1998-03-09 富士電機株式会社 低融点金属対策を施したるつぼ形誘導炉
FR2693073A1 (fr) * 1992-06-24 1993-12-31 Celes Dispositif de protection et de refroidissement des pôles d'un inducteur électro-magnétique.
KR100880597B1 (ko) * 2001-04-17 2009-01-30 히타치 긴조쿠 가부시키가이샤 자장 중 열처리로를 이용한 열처리 방법
US7588342B2 (en) * 2006-04-24 2009-09-15 Energy Focus, Inc. Lighted refrigerated display case with remote light source

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3774002A (en) * 1972-11-21 1973-11-20 Park Ohio Industries Inc Guide means for induction heating coil

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE404606C (de) * 1923-10-31 1924-10-23 Edmund Schroeder Verfahren und Vorrichtung zum Erwaermen von Metallbaendern
US1823908A (en) * 1930-09-20 1931-09-22 Westinghouse Electric & Mfg Co Induction furnace
US2005901A (en) * 1932-07-29 1935-06-25 Westinghouse Electric & Mfg Co Induction sheet heater
FR1034097A (fr) * 1950-03-18 1953-07-17 Asea Ab Four à induction à haute fréquence
US2781437A (en) * 1953-09-10 1957-02-12 Magnethermic Corp Induction furnaces
US2848566A (en) * 1954-02-01 1958-08-19 Smith Corp A O Induction heating apparatus for fusing vitreous enamel
DE1182373B (de) * 1963-05-30 1964-11-26 Siemens Ag Querfeld-Induktionsofen
DE1565381A1 (de) * 1966-06-04 1970-01-15 Aeg Elotherm Gmbh Induktionserwaermungseinrichtung unter Verwendung eines Querfeldinduktors
US3663782A (en) * 1971-06-10 1972-05-16 United States Steel Corp Laminated iron core induction corner-heating unit
US3744002A (en) * 1972-06-30 1973-07-03 Westinghouse Electric Corp Bus duct with plug-in unit for closely spaced bus bars

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3774002A (en) * 1972-11-21 1973-11-20 Park Ohio Industries Inc Guide means for induction heating coil

Also Published As

Publication number Publication date
FR2457619A2 (fr) 1980-12-19
JPS55155489A (en) 1980-12-03
DK218980A (da) 1980-11-24
DE3064098D1 (en) 1983-08-18
CH635921A5 (fr) 1983-04-29
US4339625A (en) 1982-07-13
FR2457619B2 (de) 1982-10-29
CA1140192A (fr) 1983-01-25
EP0020215A1 (de) 1980-12-10

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