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EP0170556A1 - Electromagnetic induction device for the heating of metallic elements - Google Patents

Electromagnetic induction device for the heating of metallic elements Download PDF

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Publication number
EP0170556A1
EP0170556A1 EP85401260A EP85401260A EP0170556A1 EP 0170556 A1 EP0170556 A1 EP 0170556A1 EP 85401260 A EP85401260 A EP 85401260A EP 85401260 A EP85401260 A EP 85401260A EP 0170556 A1 EP0170556 A1 EP 0170556A1
Authority
EP
European Patent Office
Prior art keywords
magnetic circuit
loop
windings
wound
air gap
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
EP85401260A
Other languages
German (de)
French (fr)
Other versions
EP0170556B1 (en
Inventor
Jacques Nuns
Joseph Abraham
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.)
Electricite de France SA
Celes SA
Original Assignee
Electricite de France SA
Celes SA
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 Electricite de France SA, Celes SA filed Critical Electricite de France SA
Publication of EP0170556A1 publication Critical patent/EP0170556A1/en
Application granted granted Critical
Publication of EP0170556B1 publication Critical patent/EP0170556B1/en
Expired legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/101—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
    • H05B6/36—Coil arrangements
    • H05B6/42—Cooling of coils

Definitions

  • the present invention relates to an electromagnetic induction device for heating metallic elements.
  • This device applies to heat treatments by induction, of metallic elements and in particular of aluminum wires or bars.
  • This type of device has the advantage of being very simple but it has significant drawbacks: its performance is low for non-ferrous metals; moreover, when metallic elements such as aluminum wires or bars coming from a continuous casting system are to be treated, these elements as a result of operating incidents of the downstream mechanical system can become entangled in the solenoid and cause it to deteriorate.
  • Another type of electromagnetic induction device is also known for heating metal elements; this other device comprises a magnetic circuit having the form of a flat loop open at two ends located opposite each other, and inductor windings wound on this circuit.
  • the metallic element to be heated is blocked in the air gap located between the two ends of the loop.
  • This device is described in French patent application No. 2489645 filed on 08/28.81, in the name of the same applicant.
  • This type of device although not having the drawback of being able to be damaged during the movement of the metal wires to be treated, nevertheless presents a very low yield; this low efficiency results essentially from the location of the inductor windings on the magnetic circuit as well as from the losses occurring in the magnetic circuit and The windings. These windings are in fact located far enough from the air gap and the efficiency is fairly low because of the eddy current losses and thermal losses.
  • the object of the invention is to remedy the drawbacks mentioned above and in particular to produce an electromagnetic induction device, for heating metallic elements, having a high efficiency, in which the thermal losses and the eddy current losses are minimized. ;
  • the shape of the device also makes it possible to heat metal elements having the form of rod wires or wires circulating in the air gap continuously, without risk of deterioration.
  • the subject of the invention is an electromagnetic induction device for heating metal elements comprising at least one magnetic circuit in an open planar loop at two ends located face to face, an inductor wound on this magnetic circuit, the element to be heated being placed in the air gap located between the two ends of the loop, characterized in that said inductor comprises two windings wound on the magnetic circuit, respectively near the two ends of the loop, these windings being supplied respectively by alternating electric currents in phase, each end of the loop becoming thinner in the shape of a chamfer towards the air gap, this chamfer being produced around the entire periphery of each end of the loop, the magnetic circuit comprising at least in the vicinity of said ends of the cooling means constituted by at least one conduit traversed by a cooling fluid and located inside the circuit ma genetic.
  • the windings comprise cooling means.
  • the magnetic circuit is constituted by an assembly of cut plates respectively in the form of elementary loops open at two ends, these plates being cut and assembled so that their ends form said chamfers.
  • the cooling duct inside the magnetic circuit consists of hollow plates of this magnetic circuit.
  • a notch is cut on each of the faces of the ends of the loop, perpendicular to the direction of the field created by the coil and perpendicular to the plane of the loop of the magnetic circuit.
  • each winding is constituted by a cable with several strands, wound around the inductor in the vicinity of the corresponding end of the loop.
  • said means for cooling each winding consist of a sheath containing each cable and traversed by a cooling fluid.
  • the device comprises at least one pair of identical magnetic circuits placed side by side, parallel to each other, so that their air gaps are opposite one another, the wound winding on one of the magnetic circuits being supplied by an alternating current in phase with the alternating current which supplies the other winding.
  • the single figure schematically represents a device according to the invention.
  • This device electromagnetic induction makes it possible to heat metallic elements and in particular aluminum wires or bars coming from a continuous casting system; these wires or bars must undergo a heat treatment by reheating up to 520 ° C. for example.
  • the device comprises at least one magnetic circuit 2 in a flat loop open at two ends 3, 4, located face to face.
  • This device also includes an inductor with two windings 5, 6, wound on the magnetic circuit 2, respectively near the two ends 3, 4 of the loop.
  • the metallic element to be heated is placed in the air gap 7, between the two ends of the loop;
  • the windings 5, 6 are supplied respectively by alternating electric currents in phase, supplied for example by an electric source of alternating current 8.
  • Each end of the loop of the magnetic circuit 2 has the shape of a chamfer directed towards the air gap 7
  • Notches 9, 10 are cut on the faces of the ends 3, 4 of the loop of the magnetic circuit 2, perpendicular to the direction of the field created by the coils and perpendicular to the plane of the loop of the magnetic circuit. It should be noted that the chamfers are made around the entire periphery of each end of the loop.
  • the magnetic circuit can be constituted either by sheets of soft iron or by blocks of ferrite.
  • the chamfers at the opposite ends of this circuit make it possible to increase the concentration of the magnetic field, towards the metallic element to be heated.
  • the chamfers 24 and 25 also make it possible to reduce the heating of the magnetic circuit, due to the eddy currents, which would occur on the edges of the ends of the magnetic circuit, in the absence of chamfers.
  • the notches 9, 10 are intended to ensure good mechanical stability in the air gap of the heated mechanical element, in particular when the latter has the form of a wire or a bar. They in fact make it possible to produce a constant magnetic field in the air gap thus avoiding the appearance of repulsion forces which tend to eject the element to be heated from the air gap.
  • a guide piece 11 is placed in the air gap 7; this guide piece which can be constituted for example in a thermally insulating material is integral with the ends of the loop of the magnetic circuit 2 and bears on the bottom of the notches 9, 10.
  • the windings 5, 6 are wound at the ends of the loop 2 , as close as possible to the air gap, so as to avoid leakage of magnetic flux.
  • These windings consist of cables 12, 13 with several strands (of copper for example) shown diagrammatically in the figure.
  • Means for cooling the magnetic circuit 2 are also provided in the vicinity of the ends of the loop; They are constituted by conduits 19, 20 connected for example to the pump 17 and to the reservoir 18 making it possible to circulate a cooling liquid, in conduits internal to the magnetic circuit 2. These cooling circuits which are known in the State of technique, are not shown in the figure. The cooling of the iron sheets or of the ferrite blocks of the magnetic circuit 2 also makes it possible to increase the efficiency of the device.
  • the cooling circuit inside the magnetic circuit can be constituted by a conduit of suitable shape or by a "water box" conforming to the shape of the magnetic circuit, in particular in the vicinity of each end of the loop, these water boxes being able to be formed by some of the plates of the magnetic circuit which can be hollow.
  • the iron plates or the ferrite blocks which constitute the magnetic circuit are assembled by means known in the prior art and not shown in the figure. These plates are cut so as to have the form of loops and so that after assembly, the ends of the magnetic circuit form chamfers.
  • the device of the invention preferably comprises a pair of identical magnetic circuits 2, 21, placed side by side, parallel to each other, so that their air gaps 7, 22 are opposite one of L 'other.
  • the second magnetic circuit 21 also includes two windings (not shown in the figure), wound at each of its ends, as well as guide means 23, in the air gap 22.
  • the windings wound on The second magnetic circuit 21 are supplied (not shown but similar to that of the windings 5, 6) by an alternating electric current in phase opposition with the alternating current which supplies the windings wound on the magnetic circuit 2.
  • the aluminum wire or bar to be heated circulates in The thermally insulating guide parts 11, 23.
  • the supply of the windings of the first and second magnetic circuits 2, 21 by alternating currents in phase opposition makes it possible to produce, respectively in the air gaps of these windings, magnetic fluxes of opposite directions; this arrangement makes it possible to avoid the presence of any magnetic flux in the circuit formed by the element to be heated and by the devices which make it possible to handle this element. Any magnetic flux in this circuit in fact causes the appearance of a current detrimental to the heating of the metallic element.
  • Tests carried out on a sample constituted by an aluminum wire of 26 mm in diameter made it possible to show that the yield of the device was 65X;
  • the device which allowed these tests has, for each of the magnetic circuits, an air gap of width 45 mm.
  • the windings, for these tests, are supplied by an alternating current with an intensity close to 2500 A and having a frequency of 280 Hz;
  • the power of the device is 14000 W.
  • the device used for the tests made it possible to bring the temperature of the aluminum wire to 520 °.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • General Induction Heating (AREA)

Abstract

L'invention concerne un dispositif à l'induction électromagnétique pour le chauffage d'éléments métalliques. Le dispositif comprend au moins un circuit magnétique (2) en boucle plane ouverte à deux extrémites (3, 4) situées face à face, un inducteur (5, 6) bobiné sur ce circuit magnétique. L'élément (1) à chauffer est placé dans l'entrefer (7) situé entre les deux extrémités de la boucle (3, 4). L'inducteur comprend deux enroulements (5, 6) bobinés sur le circuit magnétique (2), respectivement à proximité des deux extrémités (3, 4) de la boucle; ces enroulements sont alimentés respectivement par des courants électriques alternatifs en phase; chaque extrémité de la boucle plane s'amincit en forme de chanfrein vers l'entrefer. Application aux traitements thermiques par induction.The invention relates to an electromagnetic induction device for heating metallic elements. The device comprises at least one magnetic circuit (2) in planar loop open to two ends (3, 4) located face to face, an inductor (5, 6) wound on this magnetic circuit. The element (1) to be heated is placed in the air gap (7) located between the two ends of the loop (3, 4). The inductor comprises two windings (5, 6) wound on the magnetic circuit (2), respectively near the two ends (3, 4) of the loop; these windings are supplied respectively by alternating electric currents in phase; each end of the flat loop tapers in the form of a chamfer towards the air gap. Application to thermal treatments by induction.

Description

La présente invention concerne un dispositif à induction électromagnétique pour Le chauffage d'éléments métalliques. Ce dispositif s'applique aux traitements thermiques par induction, d'éléments métalliques et notamment de fils ou barres d'aluminium. On sai: réaliser des traitements thermiques à l'aide d'un inducteur solénoïde à l'intérieur duquel circule l'élë- ment metallique à traiter. Ce type de dispositif a pour avantage d'être très simple mais il présente d'importants inconvénients : son rendement est faible pour les non-ferreux ; de plus, Lorsque des éléments métalliques tels que des fils ou barres d'aluminium provenant d'un système de coulée continue, sont à traiter, ces éléments par suite d'incidents de fonctionnement du système mécanique aval peuvent venir s'enchevêtrer dans Le solénoide et provoquer sa détérioration.The present invention relates to an electromagnetic induction device for heating metallic elements. This device applies to heat treatments by induction, of metallic elements and in particular of aluminum wires or bars. We know: carry out heat treatments using a solenoid inductor inside which the metal element to be treated circulates. This type of device has the advantage of being very simple but it has significant drawbacks: its performance is low for non-ferrous metals; moreover, when metallic elements such as aluminum wires or bars coming from a continuous casting system are to be treated, these elements as a result of operating incidents of the downstream mechanical system can become entangled in the solenoid and cause it to deteriorate.

On connaît aussi un autre type de dispcsitif à induction électromagnétique, pour le chauffage d'été- ments métalliques ; cet autre dispositif comprend un circuit magnétique ayant La forme d'une boucle plane ouverte à deux extrémités situées face à face, et des enroulements inducteurs bobinés ur ce circuit. L'élément métallique à chauffer est blacé dans l'entrefer situé entre les deux extrémités de La boucle. Ce dispositif est décrit dans La demande de brevet français n° 2489645 déposée le 27/08.81, au nom du même demandeur. Ce type de dispositif, bien que ne présentant pas l'inconvénient de pouvoir être détérioré lors du déplacement des fils métalliques à traiter, présente cependant un rendement très faible ; ce faible rendement résulte essentiellement de l'emplacement des enroulements inducteurs sur le circuit magnétique ainsi que des pertes intervenant dans Le circuit magnétique et Les enroulements. Ces enroulements sont en effet situés assez loin de l'entrefer et te rendement est assez faibLe à cause des pertes par courants de Foucault et des pertes thermiques.Another type of electromagnetic induction device is also known for heating metal elements; this other device comprises a magnetic circuit having the form of a flat loop open at two ends located opposite each other, and inductor windings wound on this circuit. The metallic element to be heated is blocked in the air gap located between the two ends of the loop. This device is described in French patent application No. 2489645 filed on 08/28.81, in the name of the same applicant. This type of device, although not having the drawback of being able to be damaged during the movement of the metal wires to be treated, nevertheless presents a very low yield; this low efficiency results essentially from the location of the inductor windings on the magnetic circuit as well as from the losses occurring in the magnetic circuit and The windings. These windings are in fact located far enough from the air gap and the efficiency is fairly low because of the eddy current losses and thermal losses.

L'invention a pour but de remédier aux inconvénients mentionnés plus haut et notamment de réaliser un dispositif à induction électromagnétique, pour Le chauffage d'éléments métaLLiques, présentant un rendement élevé, dans LequeL Les pertes thermiques et Les pertes par courants de Foucault sont minimisées ; La forme du dispositif permet en outre de chauffer des éléments métalliques ayant La forme de fils barres ou de fils circulant dans L'entrefer de manière continue, sans risque de détérioration.The object of the invention is to remedy the drawbacks mentioned above and in particular to produce an electromagnetic induction device, for heating metallic elements, having a high efficiency, in which the thermal losses and the eddy current losses are minimized. ; The shape of the device also makes it possible to heat metal elements having the form of rod wires or wires circulating in the air gap continuously, without risk of deterioration.

L'invention a pour objet un dispositif à induction électromagnétique pour Le chauffage d'éléments métalliques comprenant au moins un circuit magnétique en boucle plane ouverte à deux extrémités situées face à face, un inducteur bobiné sur ce circuit magnétique, L'éLément à chauffer étant placé dans L'entrefer situé entre Les deux extrémités de La boucle, caractérisé en ce que Ledit inducteur comprend deux enroulements bobinés sur Le circuit magnétique, respectivement à proximité des deux extrémités de La boucle, ces enroulements étant alimentés respectivement par des courants électriques alternatifs en phase, chaque extrémité de La boucle s'amincissant en forme de chanfrein vers L'entrefer, ce chanfrein étant réalisé sur tout Le pourtour de chaque extrémité de La boucle, Le circuit magnétique comprenant au moins au voisinage desdites extrémités des moyens de refroidissement constitués par au moins un conduit parcouru par un fluide de refroidissement et situé à L'intérieur du circuit magnétique.The subject of the invention is an electromagnetic induction device for heating metal elements comprising at least one magnetic circuit in an open planar loop at two ends located face to face, an inductor wound on this magnetic circuit, the element to be heated being placed in the air gap located between the two ends of the loop, characterized in that said inductor comprises two windings wound on the magnetic circuit, respectively near the two ends of the loop, these windings being supplied respectively by alternating electric currents in phase, each end of the loop becoming thinner in the shape of a chamfer towards the air gap, this chamfer being produced around the entire periphery of each end of the loop, the magnetic circuit comprising at least in the vicinity of said ends of the cooling means constituted by at least one conduit traversed by a cooling fluid and located inside the circuit ma genetic.

Selon une autre caractéristique, Les enrouLements comprennent des moyens de refroidissement.According to another characteristic, the windings comprise cooling means.

Selon une autre caractéristique, Le circuit magnétique est constitué par un assemblage de plaques découpées respectivement en forme de boucles élémentaires ouvertes à deux extrémités, ces plaques étant découpées et assemblées pour que leurs extrémités forment lesdits chanfreins.According to another characteristic, the magnetic circuit is constituted by an assembly of cut plates respectively in the form of elementary loops open at two ends, these plates being cut and assembled so that their ends form said chamfers.

SeLon une autre caractéristique, le conduit de refroidissement à l'intérieur du circuit magnétique est constitué par des plaques creuses de ce circuit magnétique.According to another characteristic, the cooling duct inside the magnetic circuit consists of hollow plates of this magnetic circuit.

Selon une autre caractéristique, une encoche est taillée sur chacune des faces des extrémités de La boucle, perpendiculairement à La direction du champ créée par La bobine et perpendiculairement au plan de La boucle du circuit magnétique.According to another characteristic, a notch is cut on each of the faces of the ends of the loop, perpendicular to the direction of the field created by the coil and perpendicular to the plane of the loop of the magnetic circuit.

Selon une autre caractéristique, chaque enroulement est consttitué par un câble à plusieurs brins, bobiné autour de l'inducteur au voisinage de l'extrémité correspondante de la boucle.According to another characteristic, each winding is constituted by a cable with several strands, wound around the inductor in the vicinity of the corresponding end of the loop.

Selon une autre caractéristique, lesdits moyens de refroidisserent de chaque enroulement sont constitués par une gaine contenant chaque câble et parcourue par un fluide de refroidissement.According to another characteristic, said means for cooling each winding consist of a sheath containing each cable and traversed by a cooling fluid.

Selon une autre caractéristique, Le dispositif comprend au moins une paire de circuits magnétiques identiques placés côte à côte, parallèlement l'un à L'autre, de manière que leurs entrefers soient en regard l'un de L'autre, l'enroulement bobiné sur l'un des circuits magnétiques étant alimenté par un courant alternatif en phase avec Le courant alternatif qui aLimente L'autre enroulement.According to another characteristic, the device comprises at least one pair of identical magnetic circuits placed side by side, parallel to each other, so that their air gaps are opposite one another, the wound winding on one of the magnetic circuits being supplied by an alternating current in phase with the alternating current which supplies the other winding.

Les caractéristiques et avantages de l'invention ressortiront mieux de La description qui va suivre, donnée en référence à la figure unique annexée.The characteristics and advantages of the invention will emerge more clearly from the description which follows, given with reference to the single appended figure.

La figure unique représente schématiquement un dispositif conforme à l'invention. Ce dispositif à induction électromagnétique permet de chauffer des éléments métalliques et notamment des fils ou barres d'aluminium provenant d'un système de coulée continue ; ces fils ou barres doivent subir un traitement thermique par réchauffage jusqu'à 520°C par exemple.The single figure schematically represents a device according to the invention. This device electromagnetic induction makes it possible to heat metallic elements and in particular aluminum wires or bars coming from a continuous casting system; these wires or bars must undergo a heat treatment by reheating up to 520 ° C. for example.

Le dispositif comprend au moins un circuit magnétique 2 en boucle plane ouverte à deux extrémités 3, 4, situées face à face. Ce dispositif comprend aussi un inducteur à deux enroulements 5, 6, bobinés sur Le circuit magnétique 2, respectivement à proximité des deux extrémités 3, 4 de La boucle. L'éLément métallique à chauffer est placé dans L'entrefer 7, entre Les deux extrémités de La boucle ; Les enroulements 5, 6 sont alimentés respectivement par des courants électriques alternatifs en phase, fournis par exemple par une source électrique de courant alternatif 8. Chaque extrémité de La boucle du circuit magnétique 2 a La forme d'un chanfrein dirigé vers L'entrefer 7. Des encoches 9, 10 sont taillées sur Les faces des extrémités 3, 4 de La boucle du circuit magnétique 2, perpendiculairement à La direction du champ créée par Les bobines et perpendiculairement au plan de La boucle du circuit magnétique. IL est à remarquer que Les chanfreins sont réalisés sur tout Le pourtour de chaque extrémité de La boucLe.The device comprises at least one magnetic circuit 2 in a flat loop open at two ends 3, 4, located face to face. This device also includes an inductor with two windings 5, 6, wound on the magnetic circuit 2, respectively near the two ends 3, 4 of the loop. The metallic element to be heated is placed in the air gap 7, between the two ends of the loop; The windings 5, 6 are supplied respectively by alternating electric currents in phase, supplied for example by an electric source of alternating current 8. Each end of the loop of the magnetic circuit 2 has the shape of a chamfer directed towards the air gap 7 Notches 9, 10 are cut on the faces of the ends 3, 4 of the loop of the magnetic circuit 2, perpendicular to the direction of the field created by the coils and perpendicular to the plane of the loop of the magnetic circuit. It should be noted that the chamfers are made around the entire periphery of each end of the loop.

Dans les dispositifs connus, seuls sont réalisés Les chanfreins tels que 3 et 27. IL en résulte, dans ces dispositifs connus, des pertes LocaLisées par courants de Foucault. En effet, en L'absence de chanfreins tels que 25, des lignes du champ magnétique se referment perpendiculairement aux tôles du circuit magnétique, en passant à L'extérieur de L'entrefer. L'une de ces Lignes est représentée en traits interrompus en 26. Dans L'invention, ces Lignes n'existent évidemment pas, justement grâce aux chanfreins tels que 25. Les pertes par courants de Foucault sont minimisées et Le rendement du dispositif est bien meilleur. Dans l'invention, seules sont présentes des lignes de champ magnétique perpendiculaires aux deux faces en regard des deux extrémités de la boucle, dans l'entrefer.In the known devices, only the chamfers such as 3 and 27 are produced. In these known devices, this results in losses localized by eddy currents. Indeed, in the absence of chamfers such as 25, lines of the magnetic field close perpendicularly to the sheets of the magnetic circuit, passing outside of the air gap. One of these lines is shown in broken lines at 26. In the invention, these lines obviously do not exist, precisely thanks to the chamfers such as 25. The Eddy current losses are minimized and the efficiency of the device is much better. In the invention, only magnetic field lines are present perpendicular to the two faces opposite the two ends of the loop, in the air gap.

Le circuit magnétique peut être constitué- soit par des tôles de fer doux, soit par des blocs de ferrite. Les chanfreins aux extrémités opposées de ce circuit permettent d'augmenter La concentration du champ magnétique, vers l'élément métallique à chauffer. Les chanfreins 24 et 25 permettent également de réduire les échauffements du circuit magnétique, dus aux courants de Foucault, qui se produiraient sur Les bords des extrémités du circuit magnétique, en absence de chanfreins. Les encoches 9, 10 sont destinées à assurer dans l'entrefer une bonne stabilité mécanique de l'élément mécanique chauffé, notamment lorsque celui-ci a la forme d'un fil ou d'une barre. Elles permettent en fait de produire un champ magnétique constant dans L'entrefer évitant ainsi l'apparition de forces ce répulsion qui ont tendance à éjecter de L'entrefer l'élément à chauffer. En effet, en absence d'encoche, un point d'équilibre instable apparaît à mi-hauteur de l'entrefer. De manière à parfaire le guidage de l'élément métallique à chauffer, notamment Lorsque celui-ci a La forme d'un fil ou d'une barre, une pièce de guidage 11 est placée dans l'entrefer 7 ; cette pièce de guidage qui peut être constituée par exemple dans un matériau thermiquement isolant est solidaire des extrémités de La boucle du circuit magnétique 2 et prend appui au fond des encoches 9, 10. Les enroulements 5, 6 sont bobinés aux extrémités de la boucle 2, au plus près de l'entrefer, de manière à éviter les fuites de flux magnétique. Ces enroulements sont constitués par des câbles 12, 13 à plusieurs brins (de cuivre par exemple) représentés schématiquement sur La figure.The magnetic circuit can be constituted either by sheets of soft iron or by blocks of ferrite. The chamfers at the opposite ends of this circuit make it possible to increase the concentration of the magnetic field, towards the metallic element to be heated. The chamfers 24 and 25 also make it possible to reduce the heating of the magnetic circuit, due to the eddy currents, which would occur on the edges of the ends of the magnetic circuit, in the absence of chamfers. The notches 9, 10 are intended to ensure good mechanical stability in the air gap of the heated mechanical element, in particular when the latter has the form of a wire or a bar. They in fact make it possible to produce a constant magnetic field in the air gap thus avoiding the appearance of repulsion forces which tend to eject the element to be heated from the air gap. Indeed, in the absence of a notch, an unstable equilibrium point appears halfway up the air gap. So as to perfect the guidance of the metal element to be heated, in particular When the latter has the form of a wire or a bar, a guide piece 11 is placed in the air gap 7; this guide piece which can be constituted for example in a thermally insulating material is integral with the ends of the loop of the magnetic circuit 2 and bears on the bottom of the notches 9, 10. The windings 5, 6 are wound at the ends of the loop 2 , as close as possible to the air gap, so as to avoid leakage of magnetic flux. These windings consist of cables 12, 13 with several strands (of copper for example) shown diagrammatically in the figure.

Des moyens de refroidissement des enroulements sont prévus :

  • Dans le mode de réalisation de l'invention, ils sont constitués par des gaines plastiques 15, 16 enrobant Les câbles et dans lesquelles circule un Liquide de refroidissement, provenant d'une pompe 17 reLiée à un réservoir 18 contenant ce Liquide de refroidissement (de L'eau par exemple). Le refroidissement des enroulements permet de Limiter Les pertes par courants de Foucault dues à L'induction qui sort du circuit magnétique ; Le rendement du dispositif est accru par ce type d'inducteur.
Winding cooling means are provided:
  • In the embodiment of the invention, they are constituted by plastic sheaths 15, 16 coating the cables and in which a coolant circulates, coming from a pump 17 connected to a reservoir 18 containing this coolant (of Water for example). The cooling of the windings makes it possible to limit the losses by eddy currents due to the induction which leaves the magnetic circuit; The efficiency of the device is increased by this type of inductor.

Des moyens de refroidissement du circuit magnétique 2 sont également prévus au voisinage des extrémités de La boucle ; iLs sont constitués par des conduits 19, 20 reliés par exemple à La pompe 17 et au réservoir 18 permettant de faire circuler un Liquide de refroidissement, dans des conduits internes au circuit magnétique 2. Ces circuits de refroidissement qui sont connus dans L'état de la technique, ne sont pas représentés sur La figure. Le refroidissement des tôLes de fer ou des blocs de ferrite du circuit magnétique 2, permet aussi d'accroître Le rendement du dispositif.Means for cooling the magnetic circuit 2 are also provided in the vicinity of the ends of the loop; They are constituted by conduits 19, 20 connected for example to the pump 17 and to the reservoir 18 making it possible to circulate a cooling liquid, in conduits internal to the magnetic circuit 2. These cooling circuits which are known in the State of technique, are not shown in the figure. The cooling of the iron sheets or of the ferrite blocks of the magnetic circuit 2 also makes it possible to increase the efficiency of the device.

Le circuit de refroidissement à L'intérieur du circuit magnétique peut être constitué par un conduit de forme appropriée ou par une "boîte à eau" épousant La forme du circuit magnétique, notamment au voisinage de chaque extrémité de La boucle, ces boîtes à eau pouvant être constituées par certaines des plaques du circuit magnétique qui peuvent être creuses. Les plaques de fer ou les blocs de ferrite qui constituent Le circuit magnétique sont assemblés par des moyens connus dans L'état de la technique et non représentés sur La figure. Ces plaques sont découpées de manière à présenter La forme de boucles et de manière qu'après assemblage, les extrémités du circuit magnétique forment des chanfreins.The cooling circuit inside the magnetic circuit can be constituted by a conduit of suitable shape or by a "water box" conforming to the shape of the magnetic circuit, in particular in the vicinity of each end of the loop, these water boxes being able to be formed by some of the plates of the magnetic circuit which can be hollow. The iron plates or the ferrite blocks which constitute the magnetic circuit are assembled by means known in the prior art and not shown in the figure. These plates are cut so as to have the form of loops and so that after assembly, the ends of the magnetic circuit form chamfers.

Le dispositif de L'invention comprend de préférence une paire de circuits magnétiques 2, 21, identiques, placés côte à côte, parallèlement L'un à L'autre, de manière que Leurs entrefers 7, 22 soient en regard L'un de L'autre. Le deuxième circuit magnétique 21 comprend aussi deux enroulements (non représentés sur La figure), bobinés à chacune de ses extrémités, ainsi que des moyens de guidage 23, dans L'entrefer 22. Les enroulements bobinés sur Le deuxième circuit magnétique 21 sont alimentés (de manière non représentée mais semblable à celle des enroulements 5, 6) par un courant électrique alternatif en opposition de phase avec Le courant alternatif qui alimente Les enroulements bobinés sur Le circuit magnétique 2. Le fil ou La barre d'aluminium à chauffer circulent dans Les pièces de guidage thermiquement isolante 11, 23.The device of the invention preferably comprises a pair of identical magnetic circuits 2, 21, placed side by side, parallel to each other, so that their air gaps 7, 22 are opposite one of L 'other. The second magnetic circuit 21 also includes two windings (not shown in the figure), wound at each of its ends, as well as guide means 23, in the air gap 22. The windings wound on The second magnetic circuit 21 are supplied ( not shown but similar to that of the windings 5, 6) by an alternating electric current in phase opposition with the alternating current which supplies the windings wound on the magnetic circuit 2. The aluminum wire or bar to be heated circulates in The thermally insulating guide parts 11, 23.

L'alimentation des enroulements des premier et deuxième circuits magnétiques 2, 21 par des courants alternatifs en opposition de phase permet de produire respectivement, dans Les entrefers de ces enroulements, des flux magnétiques de sens opposés ; cette disposition permet d'éviter La présence de tout flux magnétique dans Le circuit formé par l'élément à réchauffer et par les appareils qui permettent de manipuler cet éLément. Tout flux magnétique dans ce circuit provoque en effet l'apparition d'un courant préjudiciable au chauffage de l'élémert métallique.The supply of the windings of the first and second magnetic circuits 2, 21 by alternating currents in phase opposition makes it possible to produce, respectively in the air gaps of these windings, magnetic fluxes of opposite directions; this arrangement makes it possible to avoid the presence of any magnetic flux in the circuit formed by the element to be heated and by the devices which make it possible to handle this element. Any magnetic flux in this circuit in fact causes the appearance of a current detrimental to the heating of the metallic element.

Des essais effectués sur un échantillon constitué par un fil d'aluminium de 26 mm de diamètre ont permis de montrer que Le rendement du dispositif était de 65X ; Le dispositif qui a permis ces essais présente, pour chacun des circuits magnétiques, un entrefer de Largeur 45 mm. Les enroulements, pour ces essais, sont alimentés par un courant alternatif d'intensité voisine de 2500 A et présentant une fréquence de 280 Hz ; La puissance du dispositif est de 14000 W. Le dispositif mis en oeuvre pour Les essais a permis de porter La température du fil d'aluminium à 520°.Tests carried out on a sample constituted by an aluminum wire of 26 mm in diameter made it possible to show that the yield of the device was 65X; The device which allowed these tests has, for each of the magnetic circuits, an air gap of width 45 mm. The windings, for these tests, are supplied by an alternating current with an intensity close to 2500 A and having a frequency of 280 Hz; The power of the device is 14000 W. The device used for the tests made it possible to bring the temperature of the aluminum wire to 520 °.

Claims (8)

1. Dispositif à induction électromagnétique pour Le chauffage d'éléments métalliques (1), comprenant au moins un circuit magnétique (2) en boucle plane ouverte à deux extrémités (3, 4) situées face à face, un inducteur (5, 6) bobiné sur ce circuit magnétique, L'éLément (1) à chauffer étant placé dans L'entrefer (7) situé entre Les deux extrémités de La boucle (3, 4), caractérisé en ce que Ledit inducteur comprend deux enroulements (5, 6) bobinés sur Le circuit magnétique (2), respectivement à proximité des deux extrémités (3, 4) de La boucle, ces enroulements étant alimentés respectivement par des courants électriques alternatifs en phase, chaque extrémité de La boucle s'amincissant en forme de chanfrein vers t'entrefer, ce chanfrein étant réalisé sur tout Le pourtour de chaque extrémité de La boucle, Le circuit magnétique (2) comprenant au moins au voisinage desdites extrémités (3, 4), des moyens de refroidissement (17, 18, 19, 20) constitués par au moins un conduit parcouru par un fluide de refroidissement et situé à l'intérieur du circuit magnétique.1. Electromagnetic induction device for heating metallic elements (1), comprising at least one magnetic circuit (2) in open planar loop at two ends (3, 4) located face to face, an inductor (5, 6) wound on this magnetic circuit, the element (1) to be heated being placed in the air gap (7) located between the two ends of the loop (3, 4), characterized in that said inductor comprises two windings (5, 6 ) wound on the magnetic circuit (2), respectively near the two ends (3, 4) of the loop, these windings being supplied respectively by alternating electric currents in phase, each end of the loop becoming thinner in the shape of a chamfer. towards the air gap, this chamfer being produced around the entire periphery of each end of the loop, the magnetic circuit (2) comprising at least in the vicinity of said ends (3, 4), cooling means (17, 18, 19, 20) constituted by at least one conduit traversed by a fl coolant and located inside the magnetic circuit. 2. Dispositif selon La revendication 1, caractérisé en ce que les enroulements (5, 6) comprennent des moyens de refroidissement (15, 16, 17, 18).2. Device according to claim 1, characterized in that the windings (5, 6) comprise cooling means (15, 16, 17, 18). 3. Dispositif selon L'une quelconque des revendications 1 et 2, caractérisé en ce que Le circuit magnétique (2) comprend un assemblage de plaques découpées respectivement en forme de boucles élémentaires ouvertes à deux extrémités, ces plaques étant découpées et assemblées pour que leurs extrémités (3, 4) forment Lesdits chanfreins.3. Device according to any one of claims 1 and 2, characterized in that the magnetic circuit (2) comprises an assembly of cut plates respectively in the form of elementary loops open at two ends, these plates being cut and assembled so that their ends (3, 4) form said chamfers. 4. Dispositif selon La revendication 3, caractérisé en ce que Le conduit de refroidissement à L'intérieur du circuit magnétique est constitué par des plaques creuses de ce circuit magnétique.4. Device according to claim 3, characterized in that the cooling duct inside the magnetic circuit consists of hollow plates of this magnetic circuit. 5. Dispositif selon La revendication 4, caractérisé en ce qu'une encoche (9 ou 10) est taillée sur chacune des faces des extrémités (3, 4) de La boucLe (2), perpendiculairement à La direction du champ créé par La bobine et perpendiculairement au plan de La boucle.5. Device according to claim 4, characterized in that a notch (9 or 10) is cut on each of the faces of the ends (3, 4) of the loop (2), perpendicular to the direction of the field created by the coil and perpendicular to the plane of the loop. 6. Dispositif selon la revendication 5, caractérisé en ce que chaque enroulement (5 ou 6) est constitué par un câble (12 ou 13) à plusieurs brins, bobiné autour du circuit magnétique (2) au voisinage de L'extrémité correspondante de La boucle.6. Device according to claim 5, characterized in that each winding (5 or 6) is constituted by a cable (12 or 13) with several strands, wound around the magnetic circuit (2) in the vicinity of the corresponding end of La loop. 7. Dispositif selon la revendication 6, caractérisé en ce que lesdits moyens de refroidissement de chaque enroulement sont constitués par une gaine (15 ou 16) contenant chaque câble (12 ou 13) et parcourue par un fluide de refroidissement.7. Device according to claim 6, characterized in that said cooling means of each winding consist of a sheath (15 or 16) containing each cable (12 or 13) and traversed by a cooling fluid. 8. Dispositif selon La revendication 7, caractérisé en ce qu'il comprend au moins une paire de circuits magnétiques (2, 21) identiques placés côte à côte, parallèlement L'un à L'autre de manière que leurs entrefers (7, 22) soient en regard l'un de l'autre, l'enroulement bobiné sur L'un des circuits magnétiques (2) étant alimenté par un courant alternatif en opposition de phase avec Le courant alternatif qui alimente l'enroulement bobiné sur L'autre circuit (21).8. Device according to claim 7, characterized in that it comprises at least one pair of identical magnetic circuits (2, 21) placed side by side, parallel to each other so that their air gaps (7, 22 ) are facing each other, the winding wound on one of the magnetic circuits (2) being supplied by an alternating current in phase opposition with the alternating current which supplies the winding wound on the other circuit (21).
EP85401260A 1984-06-28 1985-06-24 Electromagnetic induction device for the heating of metallic elements Expired EP0170556B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8410225 1984-06-28
FR8410225A FR2566986B1 (en) 1984-06-28 1984-06-28 ELECTROMAGNETIC INDUCTION DEVICE FOR HEATING METAL ELEMENTS

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EP0170556A1 true EP0170556A1 (en) 1986-02-05
EP0170556B1 EP0170556B1 (en) 1989-05-10

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US (1) US4673781A (en)
EP (1) EP0170556B1 (en)
JP (1) JPS6119095A (en)
AU (1) AU580073B2 (en)
CA (1) CA1249037A (en)
DE (1) DE3570169D1 (en)
FR (1) FR2566986B1 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3717742A1 (en) * 1987-05-26 1988-12-08 Blum Gmbh & Co E INDUCTIVE HEATED DEVICE
US4828227A (en) * 1986-12-11 1989-05-09 Institut De Recherches De La Siderurgie Francaise (Irsid) Inductor for the inductive reheating of metallurgical products
FR2630612A1 (en) * 1988-04-26 1989-10-27 Siderurgie Fse Inst Rech INDUCTOR POLES PROTECTION DEVICE AND INDUCTOR PROVIDED WITH SAID DEVICE
FR2640844A1 (en) * 1988-12-15 1990-06-22 Blum Gmbh & Co E INDUCTION HEATED DEVICE, ESPECIALLY FOR EXTRUDING PLASTIC MATERIAL
FR2657216A1 (en) * 1990-01-16 1991-07-19 Sundgau Sarl Atel Const Elect INDUCTOR FOR AN INDUCTION OVEN COMPRISING A TUBE CONDUCTED BY A COOLANT.
WO1991017644A1 (en) * 1990-05-10 1991-11-14 Techmetal Promotion Process and devices for the induction heating of a moving elongate metallurgical product
EP0459837A2 (en) * 1990-06-01 1991-12-04 Lennart A. Alfredeen Electromagnetic device for heating metal elements
EP0624999A1 (en) * 1993-02-26 1994-11-17 Lungchiang Hu Watercooled electromagnetic induction heating wok
WO1995025417A1 (en) * 1994-03-17 1995-09-21 Massachusetts Institute Of Technology Fluid cooled litz coil inductive heater and connector therefor
WO2009012895A2 (en) * 2007-07-26 2009-01-29 Zenergy Power Gmbh Induction heater
EP2276885A1 (en) * 2008-04-15 2011-01-26 Honeywell International Inc. System, apparatus, and method for induction heating using flux-balanced induction heating workcoil

Families Citing this family (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02207478A (en) * 1989-02-06 1990-08-17 Kazuo Tsumura High frequency heating device by use of current in resonance circuit
US5483042A (en) * 1990-06-04 1996-01-09 Nordson Corporation Magnetic separator
US5529703A (en) * 1990-06-04 1996-06-25 Nordson Corporation Induction dryer and magnetic separator
US5847370A (en) * 1990-06-04 1998-12-08 Nordson Corporation Can coating and curing system having focused induction heater using thin lamination cores
FR2663490B1 (en) * 1990-06-15 1992-09-11 Rotelec Sa INDUCTIVE HEATING COIL.
US5101086A (en) * 1990-10-25 1992-03-31 Hydro-Quebec Electromagnetic inductor with ferrite core for heating electrically conducting material
EP0583242B1 (en) * 1990-11-30 1997-10-29 Nordson Corporation Induction dryer and magnetic separator
ZA9210102B (en) * 1992-02-10 1993-08-24 Heron Tech Inc Induction dryer and magnetic separator
AU692351B2 (en) * 1992-05-08 1998-06-04 Nordson Corporation Induction dryer and method
WO1993023970A1 (en) * 1992-05-08 1993-11-25 Heron Technologies, Inc. Induction dryer and magnetic separator
AU665005B2 (en) * 1992-05-08 1995-12-14 Nordson Corporation Induction dryer and magnetic separator
US6043472A (en) 1996-08-28 2000-03-28 Didier-Werke Ag Assembly of tapping device and inductor therefor
US6538239B1 (en) * 1997-05-13 2003-03-25 Walter James Anderson Induction heating device for metal pieces
DE19742427A1 (en) * 1997-09-25 1999-04-08 Siemens Ag Process for solidifying winding coils of electrical machines
US6091063A (en) * 1998-11-06 2000-07-18 The Boeing Company Method for improving thermal uniformity in induction heating processes
US6084225A (en) * 1999-05-17 2000-07-04 The Lepel Corporation RF induction coil
DE19937492C2 (en) * 1999-08-07 2001-08-23 Mfh Hyperthermiesysteme Gmbh Magnetic field applicator for heating magnetic or magnetizable substances or solids in biological tissue
DE19937493C2 (en) * 1999-08-07 2001-06-07 Mfh Hyperthermiesysteme Gmbh Magnetic field applicator for heating magnetic or magnetizable substances or solids in biological tissue
US6271507B2 (en) * 1999-10-08 2001-08-07 Molex Incorporated Apparatus and method for bonding conductors
CA2789978C (en) * 2010-02-19 2015-11-24 Nippon Steel Corporation Transverse flux induction heating device
CN103222337B (en) * 2010-09-23 2015-08-05 康讯公司 The transverse flux electric of the discontinuous workpiece in magnetic circuit gap answers heat treated
WO2012040586A2 (en) * 2010-09-23 2012-03-29 Radyne Corporation Electric induction heat treatment of longitudinally-oriented workpieces
US9596720B2 (en) 2013-03-15 2017-03-14 ProtoParadigm LLC Inductively heated extruder heater

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2457843A (en) * 1944-09-02 1949-01-04 Ohio Crankshaft Co Flexible conductor for induction heating
FR2140510A1 (en) * 1971-06-10 1973-01-19 Uss Eng & Consult
DE2315502A1 (en) * 1972-03-28 1973-10-04 Elin Union Ag ARRANGEMENT FOR INDUCTIVE HEATING OF METALLIC WORKPIECES WITH SMALL CROSS-SECTION DIMENSIONS COMPARED TO THE LENGTH, SUCH AS WIRES IN PARTICULAR
GB1421493A (en) * 1973-05-22 1976-01-21 Electricity Council Heat treatment of saw blades composition for pre-coating plastics sheets or films with adhesive materials
FR2404371A1 (en) * 1977-09-21 1979-04-20 Onera (Off Nat Aerospatiale) Electrical induction heating coils - have rigid U=shape with two rectangular coils in series
FR2489645A1 (en) * 1980-08-27 1982-03-05 Electricite De France Induction heat treatment plant for non:ferromagnetic wire - using electromagnet coil on ferrite yoke with narrow air gap through which wire travels
US4359620A (en) * 1977-12-06 1982-11-16 Amp Incorporated Induction heating apparatus

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3467806A (en) * 1968-04-25 1969-09-16 Westinghouse Electric Corp Induction heating device
US4029926A (en) * 1974-10-29 1977-06-14 Roper Corporation Work coil for use in an induction cooking appliance
US4281234A (en) * 1979-04-20 1981-07-28 Emerson Electric Co. Method of induction annealing squirrel cage rotors

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2457843A (en) * 1944-09-02 1949-01-04 Ohio Crankshaft Co Flexible conductor for induction heating
FR2140510A1 (en) * 1971-06-10 1973-01-19 Uss Eng & Consult
DE2315502A1 (en) * 1972-03-28 1973-10-04 Elin Union Ag ARRANGEMENT FOR INDUCTIVE HEATING OF METALLIC WORKPIECES WITH SMALL CROSS-SECTION DIMENSIONS COMPARED TO THE LENGTH, SUCH AS WIRES IN PARTICULAR
GB1421493A (en) * 1973-05-22 1976-01-21 Electricity Council Heat treatment of saw blades composition for pre-coating plastics sheets or films with adhesive materials
FR2404371A1 (en) * 1977-09-21 1979-04-20 Onera (Off Nat Aerospatiale) Electrical induction heating coils - have rigid U=shape with two rectangular coils in series
US4359620A (en) * 1977-12-06 1982-11-16 Amp Incorporated Induction heating apparatus
FR2489645A1 (en) * 1980-08-27 1982-03-05 Electricite De France Induction heat treatment plant for non:ferromagnetic wire - using electromagnet coil on ferrite yoke with narrow air gap through which wire travels

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4828227A (en) * 1986-12-11 1989-05-09 Institut De Recherches De La Siderurgie Francaise (Irsid) Inductor for the inductive reheating of metallurgical products
DE3717742A1 (en) * 1987-05-26 1988-12-08 Blum Gmbh & Co E INDUCTIVE HEATED DEVICE
FR2630612A1 (en) * 1988-04-26 1989-10-27 Siderurgie Fse Inst Rech INDUCTOR POLES PROTECTION DEVICE AND INDUCTOR PROVIDED WITH SAID DEVICE
EP0340057A1 (en) * 1988-04-26 1989-11-02 Rotelec Protecting device for induction poles and inductor provided with this device
FR2640844A1 (en) * 1988-12-15 1990-06-22 Blum Gmbh & Co E INDUCTION HEATED DEVICE, ESPECIALLY FOR EXTRUDING PLASTIC MATERIAL
FR2657216A1 (en) * 1990-01-16 1991-07-19 Sundgau Sarl Atel Const Elect INDUCTOR FOR AN INDUCTION OVEN COMPRISING A TUBE CONDUCTED BY A COOLANT.
EP0438366A1 (en) * 1990-01-16 1991-07-24 Ateliers De Constructions Electriques Du Sundgau Sarl Inductor for an induction furnace, comprising a liquid-cooled tube
FR2661849A1 (en) * 1990-05-10 1991-11-15 Siderurgie Fse Inst Rech METHOD AND DEVICES FOR INDUCTION HEATING OF A METALLURGICAL PRODUCT IN AN ELONGATE SHAPE.
WO1991017644A1 (en) * 1990-05-10 1991-11-14 Techmetal Promotion Process and devices for the induction heating of a moving elongate metallurgical product
US5412183A (en) * 1990-05-10 1995-05-02 Rotelec Method and devices for induction heating during the passage of a metallurgical product of elongated shape
EP0459837A2 (en) * 1990-06-01 1991-12-04 Lennart A. Alfredeen Electromagnetic device for heating metal elements
EP0459837A3 (en) * 1990-06-01 1992-12-30 Lennart A. Alfredeen Electromagnetic device for heating metal elements
EP0624999A1 (en) * 1993-02-26 1994-11-17 Lungchiang Hu Watercooled electromagnetic induction heating wok
WO1995025417A1 (en) * 1994-03-17 1995-09-21 Massachusetts Institute Of Technology Fluid cooled litz coil inductive heater and connector therefor
WO2009012895A2 (en) * 2007-07-26 2009-01-29 Zenergy Power Gmbh Induction heater
WO2009012895A3 (en) * 2007-07-26 2009-04-30 Zenergy Power Gmbh Induction heater
EP2276885A1 (en) * 2008-04-15 2011-01-26 Honeywell International Inc. System, apparatus, and method for induction heating using flux-balanced induction heating workcoil
EP2276885A4 (en) * 2008-04-15 2014-11-19 Honeywell Int Inc System, apparatus, and method for induction heating using flux-balanced induction heating workcoil

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CA1249037A (en) 1989-01-17
FR2566986A1 (en) 1986-01-03
JPS6119095A (en) 1986-01-27
EP0170556B1 (en) 1989-05-10
JPH0586637B2 (en) 1993-12-13
DE3570169D1 (en) 1989-06-15
AU4397985A (en) 1986-01-02
AU580073B2 (en) 1988-12-22
US4673781A (en) 1987-06-16
FR2566986B1 (en) 1986-09-19

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