EP0765592A1 - Low-loss induction coil for heating and/or melting metallic materials - Google Patents

Low-loss induction coil for heating and/or melting metallic materials

Info

Publication number
EP0765592A1
EP0765592A1 EP95917895A EP95917895A EP0765592A1 EP 0765592 A1 EP0765592 A1 EP 0765592A1 EP 95917895 A EP95917895 A EP 95917895A EP 95917895 A EP95917895 A EP 95917895A EP 0765592 A1 EP0765592 A1 EP 0765592A1
Authority
EP
European Patent Office
Prior art keywords
strand
induction coil
current
coil 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
EP95917895A
Other languages
German (de)
French (fr)
Other versions
EP0765592B1 (en
Inventor
Dieter Schluckebier
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.)
Otto Junker GmbH
Original Assignee
Otto Junker GmbH
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 Otto Junker GmbH filed Critical Otto Junker GmbH
Publication of EP0765592A1 publication Critical patent/EP0765592A1/en
Application granted granted Critical
Publication of EP0765592B1 publication Critical patent/EP0765592B1/en
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
    • 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
    • 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 invention relates to a low-loss induction coil for heating and / or melting metallic material, with turns formed from strand-like hollow bodies and carrying a coolant.
  • Induction coils of the type mentioned above are known, which consist of copper waveguides.
  • the induction current is passed through this waveguide, while a fluid coolant, e.g. Water flowing through the inside of the waveguide.
  • a fluid coolant e.g. Water flowing through the inside of the waveguide.
  • the object of the present invention is to provide an induction coil of the type mentioned at the outset, which effectively and cost-effectively reduces the losses over the entire length of the coil.
  • this object is achieved according to the invention in that a current-carrying element in the form of at least one strand consisting of insulated individual conductors is provided in the turns in at least one of the end regions of the induction coil and in that the remaining turns as Waveguide formed and each electrically connected to the current-carrying element.
  • the current is led through strands, which largely prevents losses due to cross fields. be avoided. Furthermore, it has been shown empirically that when stranded wires are used, the active area of the coil is longer than when using waveguides. The reason for this is presumably a lower permeability of the strand windings to transverse fields, since here the current density is distributed uniformly over the strand cross section. In the case of waveguides, on the other hand, the current density can concentrate on partial areas of the cross section, as a result of which other areas remain almost current-free and thus offer gaps for the passage of transverse fields.
  • the simple and inexpensive construction variant is used with the waveguides.
  • the use of waveguides minimizes the average distance between the current density and the material to be heated, which also minimizes the distance-related losses.
  • the coil according to the invention can be designed in such a way that the strand-shaped hollow bodies receiving the strand (s) consist of a non-magnetic, poorly conductive material.
  • the induction coil according to the invention can also be designed in such a way that the strand-shaped hollow bodies receiving the strand (s) consist of V2A stainless steel.
  • V2A stainless steel In addition to its thermal and chemical resistance, V2A stainless steel has the advantage of low electrical conductivity for the application concerned. As a result, the occurrence of eddy currents in the strand-shaped hollow body carrying the fluid coolant is avoided.
  • the induction coil according to the invention can be designed such that the waveguide and the individual conductors of the L1tz ⁇ (n) are made of copper.
  • the induction coil according to the invention can also be designed in such a way that each strand is surrounded by an insulation which is thermally resistant to the coolant.
  • the individual conductors of the stranded wire are held together and, moreover, are protected against mechanical loads and against a possibly harmful action of the coolant.
  • the induction coil according to the invention can also be designed in such a way that a coolant is provided for the cooling anal within a strand.
  • the induction coil according to the invention can be designed such that a plurality of strands form a bundle of strands which is surrounded by an insulation which is thermally resistant to the coolant.
  • the induction coil according to the invention can also be designed such that a cooling duct guiding the coolant is provided within a strand bundle.
  • the induction coil according to the invention can be designed such that the cross section of the strand-shaped hollow bodies is rectangular.
  • the induction coil according to the invention can be designed in such a way that at the end adjacent to the waveguide of each strand-shaped hollow body receiving the strands (s), on the outside of the coil, there is a power connector that is electrically connected to the strand (s).
  • the rectangular profile of the strand-like hollow bodies has a greater positional stability of the individual turns lying on top of one another than round profiles. Furthermore given the dimensions of the width and height of the hollow body in the rectangular profile, the volume of the space enclosed therewith is maximum, which also maximizes the coolant throughput. In addition, disturbing free spaces between the waveguides designed in this way can practically be eliminated.
  • the rectangular profile keeps the radial distance between the current conductor and the metallic material uniformly low, while in the case of a round waveguide this distance is changed periodically.
  • the uniformity of this distance which results in the rectangular profile is advantageous since, as already explained above, the induction current density in the region of the inside of the coil is maximum in the part of an induction coil consisting of a waveguide.
  • the induction current in the case of a rectangular profile runs closer to the metallic material, thus reducing losses.
  • FIG. 1 schematically shows an induction furnace with a crucible 1 for receiving a metallic good, not shown here, and with an induction coil 2, the magnetic field of which produces eddy currents in the metallic good, which heat this good.
  • the turns of the induction coil 2 are formed from strand-shaped hollow bodies 3, 4 with a rectangular profile.
  • the hollow bodies are the current-carrying waveguide 3 made of copper.
  • the hollow bodies 4 consist of V2A stainless steel, and the induction current is conducted within these hollow bodies 4 through strands 6 made of copper.
  • means for the electrical connection 7 of the strand 6 to the waveguide 3 are only shown schematically.
  • Cooling rings 5 are attached above and below the induction coil 2 to increase the heat dissipation.
  • the cooling rings 5 do not carry an induction current, but only conduct a fluid coolant.
  • FIG. 2 shows an enlarged cross section of a hollow body 4 with a strand 6 running therein.
  • the hollow body 4 has a low electrical conductivity compared to copper, which is why there are no significant eddy currents in its walls due to magnetic alternation selfelder induced.
  • the strand 6 consists of a large number of individual conductors which are insulated from one another, so that here too no extensive eddy currents can be induced.
  • the strand 6 is surrounded by a hose 8, which holds the strand 6 together, against mechanical loads and also protects against possible effects of the fluid coolant.
  • Fig. 4 illustrates how the electrical connection of the strand 6 to the waveguide 3 can be carried out.
  • a connecting piece 10 is provided on the hollow body 4, through which a hose 11 made of glass fabric is placed.
  • an electrically conductive plug 12 for example made of copper, which seals the hose 11 and is electrically connected to the strand 6 at one end and outside the hose 11 at its other end has a power terminal 13.
  • the waveguide 3, not shown in this figure, can be electrically connected to this.
  • the stopper 12 also has a coolant channel 14 which can allow the coolant to exit or pass on.
  • a liquid or gaseous coolant can be used to cool the induction coil.
  • Connection piece 11 Glass fabric hose

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • General Induction Heating (AREA)
  • Furnace Details (AREA)

Abstract

Described is a low-loss induction coil (2) for heating and/or melting metallic materials, the coil having windings formed by lengths of hollow tubing (3, 4) carrying a fluid coolant. In the central zone of the induction coil (2), the current is carried by hollow conductors (3) made of copper which at the same time form the hollow tubing. Fitted at least in the windings at one end of the coil (2) is a current-carrying element in the form of at least one braid (6) whose individual conductors are insulated from each other, while remaining windings are designed as hollow conductors (3) connected to the current-carrying element. The use of braids (6) as the current carrier leads, at the end of the coil, to a reduction in eddy-current losses caused by transverse magnetic fields, while the use of hollow conductors (3) in the rest of the coil results in the mean distance between the current flux and the metallic material being heated being kept at the minimum and losses due to this distance thus kept low.

Description

VERLUSTARME INDUKTIONSSPULE ZUM ERWARMEN UND/ODER SCHMELZENLOW-LOSS INDUCTION COIL FOR WARMING AND / OR MELTING
VON METALLISCHEM GUTOF METAL GOODS
Beschreibungdescription
Die Erfindung betrifft eine verlustarme Induktionsspule zum Erwärmen und/oder Schmelzen von metallischem Gut, mit aus strangförmigen Hohlkörpern gebildeten, ein Kühlmittel füh¬ renden Windungen.The invention relates to a low-loss induction coil for heating and / or melting metallic material, with turns formed from strand-like hollow bodies and carrying a coolant.
Es sind Induktionsspulen der oben genannten Art bekannt, die aus Kupferhohlleitern bestehen. Durch diese Hohlleiter wird der Induktionsstrom geführt, während ein fluides Kühl¬ mittel, z.B. Wasser, das Innere der Hohlleiter durchströmt. In den Endbereichen derartig gestalteter Induktionsspulen kommt es zu erhöhten Energieverlusten, da die dort ver¬ stärkt auftretenden magnetischen Querfelder im Kupferhohl¬ leiter Wirbelströme induzieren.Induction coils of the type mentioned above are known, which consist of copper waveguides. The induction current is passed through this waveguide, while a fluid coolant, e.g. Water flowing through the inside of the waveguide. Increased energy losses occur in the end regions of induction coils of this type, since the magnetic transverse fields which occur there more strongly induce eddy currents in the copper waveguide.
Aus der EP 0 240 099 A2 ist es bekannt, den Induktionsstrom ausschl ießlich durch mehrere parallel zueinander verlau¬ fende, gegeneinander isolierte, zu Litzen zusammengefaßte Einzelleiter zu führen. Dabei ist der Querschnitt der Ein¬ zelleiter so dimensioniert, daß keine wesentlichen Wirbel¬ ströme in den Endbereichen derartiger Induktionsspulen auf- treten können.It is known from EP 0 240 099 A2 to conduct the induction current exclusively through a plurality of individual conductors which run parallel to one another and are insulated from one another and are combined to form strands. The cross section of the individual conductors is dimensioned such that no significant eddy currents can occur in the end regions of such induction coils.
Diese Induktionsspulen haben gegenüber den Induktionsspulen aus Hohlleitern den Nachteil, daß ihre Herstellung und auch die für die Gewährleistung einer ausreichenden Kühlung ei— forderlichen Maßnahmen aufwendiger und kostspieliger sind. Die Einzelleiter bzw. Litzen müssen trotz der sie umgeben¬ den elektrisch isolierenden Mittel , z.B. Lack oder Isolationsschlauch, in einem guten thermischen Kontakt zum Kühlmittel stehen.Compared to the induction coils made of waveguides, these induction coils have the disadvantage that their manufacture and also the measures required to ensure adequate cooling are more complex and costly. The individual conductors or strands, despite the electrically insulating means surrounding them, for example lacquer or Isolation hose, in good thermal contact with the coolant.
Ein weiterer Nachteil des Stromtransportes durch Litzen, d.h. durch eine Vielzahl von Einzelleitern, ergibt sich aus der dadurch bedingten räumlichen Verteilung der Strom¬ dichte. Da jeder Einzelleiter Strom führt, ist die Strom¬ dichte in etwa gleichmäßig über dem Litzenquerschnitt ver¬ teilt und damit der mittlere Abstand zwischen Induktions- ström und dem zu erwärmenden metallischen Gut in etwa durch die Litzenmitte bestimmt. Bei Hohlleitern dagegen konzen¬ triert sich die Stromdichte auf den der Innenfläche der In¬ duktionsspule zugewandten Teil des Hohlleiterquerschnittes. Bei gleichem Spuleninnenradius ist also bei einer Litzen- spule der mittlere Abstand zwischen Induktionsstrom und dem zu erwärmenden metallischen Gut höher, womit hier gleich¬ zeitig die durch diesen Abstand verursachten Verluste größer sind.Another disadvantage of current transport through strands, i.e. by a large number of individual conductors results from the spatial distribution of the current density caused thereby. Since each individual conductor carries current, the current density is distributed approximately uniformly over the cross-section of the strand, and the average distance between the induction current and the metal material to be heated is thus determined approximately by the center of the strand. In the case of waveguides, however, the current density is concentrated on the part of the waveguide cross section facing the inner surface of the induction coil. With the same coil inner radius, the mean distance between the induction current and the metal material to be heated is therefore greater for a stranded coil, which means that the losses caused by this distance are greater at the same time.
Die vorliegende Erfindung hat zur Aufgabe, eine Induktions¬ spule der eingangs erwähnten Art bereitzustellen, die wirk¬ sam und kostengünstig die Verluste über die gesamte Spulen¬ länge reduziert.The object of the present invention is to provide an induction coil of the type mentioned at the outset, which effectively and cost-effectively reduces the losses over the entire length of the coil.
Bei einer Induktionsspule der eingangs erwähnten Art wird diese Aufgabe erfindungsgemäß dadurch gelöst, daß in den Windungen in zumindest einem der Endbereiche der Indukti¬ onsspule ein stromführendes Element in Form von mindestens einer aus isolierten Einzelleitern bestehenden Litze vorge- sehen ist und daß die restlichen Windungen als Hohlleiter ausgebildet und jeweils an das stromführende Element elek¬ trisch angeschlossen sind.In the case of an induction coil of the type mentioned at the outset, this object is achieved according to the invention in that a current-carrying element in the form of at least one strand consisting of insulated individual conductors is provided in the turns in at least one of the end regions of the induction coil and in that the remaining turns as Waveguide formed and each electrically connected to the current-carrying element.
Bei einer solchen Spule kommen die Vorteile der hier mit- einander kombinierten Spulenbauweisen zur Geltung:With such a coil, the advantages of the coil designs combined here come into play:
In den Endbereichen wird der Strom durch Litzen geführt, wodurch Verluste aufgrund von Querfeldern weitgehend ver- mieden werden. Desweiteren hat sich empirisch gezeigt, daß bei der Verwendung von Litzenleitungen der aktive Bereich der Spule länger ist als bei der Verwendung von Hohllei¬ tern. Der Grund hierfür ist vermutlich eine geringere Durchlässigkeit der Litzenwindungen für Querfelder, da hier die Stromdichte gleichmäßig über dem Litzenquerschnitt ver¬ teilt ist. Bei Hohlleitern kann sich dagegen die Strom¬ dichte auf Teilbereiche des Querschnittes konzentrieren, wodurch andere Bereiche nahezu stromfrei bleiben und so Lücken für den Durchtritt von Querfeldern bieten.In the end areas, the current is led through strands, which largely prevents losses due to cross fields. be avoided. Furthermore, it has been shown empirically that when stranded wires are used, the active area of the coil is longer than when using waveguides. The reason for this is presumably a lower permeability of the strand windings to transverse fields, since here the current density is distributed uniformly over the strand cross section. In the case of waveguides, on the other hand, the current density can concentrate on partial areas of the cross section, as a result of which other areas remain almost current-free and thus offer gaps for the passage of transverse fields.
Im Mittelbereich der Spule, wo das induzierte Magnetfeld keinen wesentlichen Betrag in radialer Richtung hat, wird mit den Hohlleitern die einfache und kostengünstige Bauva- riante eingesetzt. Außerdem wird durch die Verwendung von Hohlleitern der mittlere Abstand der Stromdichte zu dem zu erwärmenden Gut minimiert, womit auch die abstandsbedingten Verluste minimiert werden.In the central region of the coil, where the induced magnetic field has no significant amount in the radial direction, the simple and inexpensive construction variant is used with the waveguides. In addition, the use of waveguides minimizes the average distance between the current density and the material to be heated, which also minimizes the distance-related losses.
Die erfindungsgemäße Spule kann so ausgebildet sein, daß die die Litze(n) aufnehmenden strangförmigen Hohlkörper aus einem unmagnetischen, schlecht leitenden Material bestehen.The coil according to the invention can be designed in such a way that the strand-shaped hollow bodies receiving the strand (s) consist of a non-magnetic, poorly conductive material.
Die erfindungsgemäße Induktionsspule kann auch so ausge- führt sein, daß die die Litze(n) aufnehmenden strangför¬ migen Hohlkörper aus V2A-Edelstahl bestehen.The induction coil according to the invention can also be designed in such a way that the strand-shaped hollow bodies receiving the strand (s) consist of V2A stainless steel.
V2A-Edelstahl hat für die hier betroffene Anwendung neben seiner thermischen und chemischen Beständigkeit den Vorteil einer geringen elektrischen Leitfähigkeit. Hierdurch wird das Auftreten von Wirbelströmen in dem das fluide Kühlmit¬ tel führenden strangförmigen Hohlkörper vermieden.In addition to its thermal and chemical resistance, V2A stainless steel has the advantage of low electrical conductivity for the application concerned. As a result, the occurrence of eddy currents in the strand-shaped hollow body carrying the fluid coolant is avoided.
Desweiteren kann die erfindungsgemäße Induktionsspule so ausgeführt sein, daß die Hohlleiter und die Einzelleiter der L1tzβ(n) aus Kupfer hergestellt sind. Die erfindungsgemäße Induktionsspule kann auch so ausge¬ führt sein, daß jede Litze von einer thermisch und gegen das Kühlmittel beständigen Isolation umgeben ist.Furthermore, the induction coil according to the invention can be designed such that the waveguide and the individual conductors of the L1tzβ (n) are made of copper. The induction coil according to the invention can also be designed in such a way that each strand is surrounded by an insulation which is thermally resistant to the coolant.
Hierdurch werden die Einzelleiter der Litze zusammengehal¬ ten und außerdem gegen mechanische Belastungen sowie gegen eine möglicherweise schädliche Einwirkung des Kühlmittels geschützt.As a result, the individual conductors of the stranded wire are held together and, moreover, are protected against mechanical loads and against a possibly harmful action of the coolant.
Die erfindungsgemäße Induktionsspule kann auch so ausgelegt sein, daß innerhalb einer Litze ein ein Kühlmittel führen¬ der Kühl anal vorgesehen ist.The induction coil according to the invention can also be designed in such a way that a coolant is provided for the cooling anal within a strand.
Hierdurch kann auch bei hohen Stromstärken eine ausrei- chende Wärmeabfuhr gewährleistet werden.In this way, sufficient heat dissipation can be ensured even at high currents.
Desweiteren kann die erfindungsgemäße Induktionsspule so ausgebildet sein, daß mehrere Litzen ein Litzenbündel bil¬ den, das von einer thermisch und gegen das Kühlmittel be- ständigen Isolation umgeben ist.Furthermore, the induction coil according to the invention can be designed such that a plurality of strands form a bundle of strands which is surrounded by an insulation which is thermally resistant to the coolant.
Die erfindungsgemäße Induktionsspule kann auch so ausgebil¬ det sein, daß innerhalb eines Litzenbündels ein das Kühl¬ mittel führender Kühlkanal vorgesehen ist.The induction coil according to the invention can also be designed such that a cooling duct guiding the coolant is provided within a strand bundle.
Außerdem kann die erfindungsgemäße Induktionsspule so aus¬ gebildet sein, daß der Querschnitt der strangförmigen Hohl¬ körper rechteckig ist.In addition, the induction coil according to the invention can be designed such that the cross section of the strand-shaped hollow bodies is rectangular.
Schließlich kann die erfindungsgemäße Induktionsspule so ausgebildet sein, daß an dem am Hohlleiter angrenzenden Ende jedes die Litze(n) aufnehmenden strangförmigen Hohl¬ körpers an der Spulenaußenseite eine mit der (den) Litze(n) elektrisch verbundene Stromanschlußklemme angebracht ist.Finally, the induction coil according to the invention can be designed in such a way that at the end adjacent to the waveguide of each strand-shaped hollow body receiving the strands (s), on the outside of the coil, there is a power connector that is electrically connected to the strand (s).
Das rechteckige Profil der strangförmigen Hohlkörper be¬ wirkt gegenüber runden Profilen eine höhere Lagestabilität der einzelnen aufeinander!iegenden Windungen. Desweiteren ist bei gegebenen Abmessungen von Breite und Höhe des Hohl¬ körpers beim rechteckigen Profil das Volumen des damit um¬ schlossenen Raumes maximal, womit auch der Kühlmitteldurch¬ satz maximiert wird. Zudem können störende Freiräume zwi- sehen so ausgebildeten Hohlleitern praktisch ausgeschaltet werden.The rectangular profile of the strand-like hollow bodies has a greater positional stability of the individual turns lying on top of one another than round profiles. Furthermore given the dimensions of the width and height of the hollow body in the rectangular profile, the volume of the space enclosed therewith is maximum, which also maximizes the coolant throughput. In addition, disturbing free spaces between the waveguides designed in this way can practically be eliminated.
Bei den als elektrische Hohlleiter ausgebildeten Windungen wird durch das rechteckige Profil der radiale Abstand zwi- sehen Stromleiter und dem metallischen Gut gleichmäßig ge¬ ring gehalten, während bei einem runden Hohlleiter dieser Abstand periodisch verändert wird. Die sich beim Rechteck¬ profil ergebende Gleichmäßigkeit dieses Abstands ist von Vorteil, da, wie oben schon ausgeführt, in dem aus einem Hohlleiter bestehenden Teil einer Induktionsspule die In¬ duktionsstromdichte im Bereich der Spuleninnenseite maximal ist. Somit verläuft über die Länge der Hohlleiterspule be¬ trachtet im Mittel der Induktionsstrom bei rechteckigem Profil näher am metallischen Gut, womit Verluste verringert werden.In the case of the windings designed as electrical waveguides, the rectangular profile keeps the radial distance between the current conductor and the metallic material uniformly low, while in the case of a round waveguide this distance is changed periodically. The uniformity of this distance which results in the rectangular profile is advantageous since, as already explained above, the induction current density in the region of the inside of the coil is maximum in the part of an induction coil consisting of a waveguide. Thus, viewed over the length of the waveguide coil, on average the induction current in the case of a rectangular profile runs closer to the metallic material, thus reducing losses.
Im folgenden werden einige Ausführungsformen der erfin¬ dungsgemäßen Induktionsspule anhand von Zeichnungen be¬ schrieben.Some embodiments of the induction coil according to the invention are described below with reference to drawings.
Es zeigtIt shows
Fig. 1: in schematischer Darstellung einen Induktionsofen mit erfindungsgemäß ausgebildeter Induktionsspule im Axialschnitt,1: a schematic representation of an induction furnace with an induction coil designed according to the invention in axial section,
Fig. 2: in schematischer Darstellung den Querschnitt ei¬ nes strangförmigen Hohlkörpers in einem der axia¬ len Endbereiche der Spule mit einer Litze als stromführendes Element,2: a schematic representation of the cross section of a strand-shaped hollow body in one of the axial end regions of the coil with a strand as a current-carrying element,
F1§. lϊ θinβ Darstellung gem. Fig. 2 mit einem in der Litze vorgesehenen Kühlkanal und Fig. 4: in schematischer Darstellung den Stromanschluß einer Litze zur Kopplung mit einem elektrischen Hohl leiter.F1§. lϊ θinβ representation acc. Fig. 2 with a cooling channel provided in the strand and Fig. 4: a schematic representation of the power connection of a stranded wire for coupling to an electrical hollow conductor.
Fig. 1 zeigt schematisch einen Induktionsofen mit einem Tiegel 1 zur Aufnahme eines hier nicht dargestellten metal¬ lischen Gutes und mit einer Induktionsspule 2, deren Ma¬ gnetfeld im metallischen Gut Wirbelströme erzeugt, welche dieses Gut erwärmen.1 schematically shows an induction furnace with a crucible 1 for receiving a metallic good, not shown here, and with an induction coil 2, the magnetic field of which produces eddy currents in the metallic good, which heat this good.
Die Windungen der Induktionsspule 2 sind aus strangförmigen Hohlkörpern 3,4 mit rechteckigem Profil gebildet. Im mitt¬ leren Bereich der Induktionsspule 2 sind die Hohlkörper den Strom führende Hohlleiter 3 aus Kupfer. Im oberen und unte¬ ren Endbereich der Induktionsspule 2 bestehen die Hohlkör¬ per 4 dagegen aus V2A-Edelstahl , und der Induktionsstrom wird innerhalb dieser Hohlkörper 4 durch Litzen 6 aus Kup¬ fer geleitet. Am Übergang zwischen Hohlleiter 3 und Hohl- körper 4 sind Mittel zum elektrischen Anschluß 7 der Litze 6 an den Hohlleiter 3 nur schematisch dargestellt.The turns of the induction coil 2 are formed from strand-shaped hollow bodies 3, 4 with a rectangular profile. In the central area of the induction coil 2, the hollow bodies are the current-carrying waveguide 3 made of copper. In the upper and lower end region of the induction coil 2, however, the hollow bodies 4 consist of V2A stainless steel, and the induction current is conducted within these hollow bodies 4 through strands 6 made of copper. At the transition between the waveguide 3 and the hollow body 4, means for the electrical connection 7 of the strand 6 to the waveguide 3 are only shown schematically.
Oberhalb und unterhalb der Induktionsspule 2 sind zur Erhö¬ hung der Wärmeabfuhr Kühlringe 5 angebracht. Die Kühlringe 5 führen keinen Induktionsstrom, sondern leiten lediglich ein fluides Kühlmittel.Cooling rings 5 are attached above and below the induction coil 2 to increase the heat dissipation. The cooling rings 5 do not carry an induction current, but only conduct a fluid coolant.
Fig. 2 zeigt vergrößert den Querschnitt eines Hohlkörpers 4 mit einer darin verlaufenden Litze 6. Aus V2A-Edelstahl be- stehend hat der Hohlkörper 4 eine im Vergleich zum Kupfer niedrige elektrische Leitfähigkeit, weshalb in seinen Wän¬ den keine wesentlichen Wirbelströme durch magnetische Wech¬ selfelder induziert werden. Die Litze 6 besteht aus einer Vielzahl von gegeneinander isolierten Einzelleitern, so daß auch hier keine ausgedehnten Wirbelströme induziert werden können. Die Litze 6 ist von einem Schlauch 8 umgeben, der die Litze 6 zusammenhält, gegen mechanische Belastungen und außerdem gegen mögliche Einwirkungen des fluiden Kühlmit¬ tels schützt.2 shows an enlarged cross section of a hollow body 4 with a strand 6 running therein. Made of V2A stainless steel, the hollow body 4 has a low electrical conductivity compared to copper, which is why there are no significant eddy currents in its walls due to magnetic alternation selfelder induced. The strand 6 consists of a large number of individual conductors which are insulated from one another, so that here too no extensive eddy currents can be induced. The strand 6 is surrounded by a hose 8, which holds the strand 6 together, against mechanical loads and also protects against possible effects of the fluid coolant.
Um die Abfuhr der durch den Strom erzeugten Wärme zu ver- bessern, ist bei der Ausführungsform gem. Fig. 3 innerhalb der Litze 6 ein Kühlkanal 9 vorgesehen.In order to improve the dissipation of the heat generated by the current, in the embodiment according to Fig. 3 provided a cooling channel 9 within the strand 6.
Fig. 4 veranschaulicht, wie der elektrische Anschluß der Litze 6 an den Hohlleiter 3 ausgeführt sein kann. Dazu ist am Hohlkörper 4 ein Anschlußstutzen 10 vorgesehen, über den ein Schlauch 11 aus Glasgewebe gestülpt ist. In das andere Ende des Schlauches 11 ist ein den Schlauch 11 abdichten¬ der, elektrisch leitender Stopfen 12, z.B aus Kupfer, ein¬ gesetzt, der an seinem einen Ende elektrisch mit der Litze 6 verbunden ist und an seinem anderen Ende außerhalb des Schlauches 11 eine Stromanschlußklemme 13 aufweist. Hieran kann der in dieser Figur nicht dargestellte Hohlleiter 3 elektrisch angeschlossen werden.Fig. 4 illustrates how the electrical connection of the strand 6 to the waveguide 3 can be carried out. For this purpose, a connecting piece 10 is provided on the hollow body 4, through which a hose 11 made of glass fabric is placed. In the other end of the hose 11 there is inserted an electrically conductive plug 12, for example made of copper, which seals the hose 11 and is electrically connected to the strand 6 at one end and outside the hose 11 at its other end has a power terminal 13. The waveguide 3, not shown in this figure, can be electrically connected to this.
Der Stopfen 12 besitzt außerdem einen Kühlmittelkanal 14 der den Austritt bzw. die Weiterleitung des Kühlmittels er¬ lauben kann.The stopper 12 also has a coolant channel 14 which can allow the coolant to exit or pass on.
Zur Kühlung der Induktionsspule kommt ein flüssiges oder gasförmiges Kühlmittel in Betracht. A liquid or gaseous coolant can be used to cool the induction coil.
BezugszeichenlisteReference list
1. Tiegel1st crucible
2. Induktionsspule2. Induction coil
3. Hohlleiter3. Waveguide
4. Hohlkörper4. Hollow body
5. Kühlwindung 6. Litze5. Cooling turn 6. Strand
7. Mittel zum elektrischen Anschluß der Litze7. Means for electrical connection of the strand
8. Isolierungsschlauch8. Insulation hose
9. Kühlkanal9. Cooling channel
10. Ansch1ußstutzen 11. Glasgewebeschlauch10. Connection piece 11. Glass fabric hose
12. Stopfen12. Plug
13. Stromanschlußklemme13. Power connector
14. Kühlmittelkanal des Stopfens 14. Coolant channel of the plug

Claims

Ansprüche Expectations
1. Verlustarme Induktionsspule (2) zum Erwärmen und/oder Schmelzen von metallischem Gut, mit aus strangför¬ migen Hohlkörpern (3,4) gebildeten, ein Kühlmittel führen¬ den Windungen, dadurch gekennzeichnet, daß in den Windungen in zumindest einem der Endbereiche der Induktionsspule (2) ein stromführendes Element (6) in Form von mindestens einer aus isolierten Einzelleitern bestehenden Litze (6) vorgese¬ hen ist und daß die restlichen Windungen als Hohlleiter (3) ausgebildet und jeweils an das stromführende Element (6) elektrisch angeschlossen sind.1. Low-loss induction coil (2) for heating and / or melting metallic material, with a coolant leading from the strand-shaped hollow bodies (3, 4), characterized in that the windings are characterized in that in the windings in at least one of the end regions Induction coil (2) is provided with a current-carrying element (6) in the form of at least one strand (6) consisting of insulated individual conductors and that the remaining turns are designed as waveguides (3) and are each electrically connected to the current-carrying element (6) .
2. Induktionsspule nach Anspruch 1, dadurch gekenn¬ zeichnet, daß die die Litze(n) (6) aufnehmenden strangför¬ migen Hohlkörper (4) aus einem unmagnetischen, schlecht leitenden Material bestehen.2. Induction coil according to claim 1, characterized gekenn¬ characterized in that the strand (s) (6) receiving strand-shaped hollow body (4) consist of a non-magnetic, poorly conductive material.
3. Induktionsspule nach Anspruch 1, dadurch gekenn¬ zeichnet, daß die die Litze(n) (6) aufnehmenden strangför¬ migen Hohlkörper (4) aus V2A-Edelstahl bestehen.3. Induction coil according to claim 1, characterized gekenn¬ characterized in that the strand (s) (6) receiving strand-shaped hollow body (4) consist of V2A stainless steel.
4. Induktionsspule nach einem der vorhergehenden An¬ sprüche, dadurch gekennzeichnet, daß die Hohlleiter (3) und die Einzelleiter der Litze(n) (6) aus Kupfer hergestellt sind.4. Induction coil according to one of the preceding claims, characterized in that the waveguide (3) and the individual conductors of the strand (s) (6) are made of copper.
5. Induktionsspule nach einem der vorherigen Ansprü¬ che, dadurch gekennzeichnet, daß jede Litze (6) von einer thermisch und gegen das Kühlmittel beständigen Isolation (8) umgeben ist.5. Induction coil according to one of the preceding Ansprü¬ che, characterized in that each strand (6) is surrounded by a thermally and against the coolant insulation (8).
6. Induktionsspule nach einem der vorherigen Ansprü¬ che, dadurch gekennzeichnet, daß innerhalb einer Litze (6) ein ein Kühlmittel führender Kühlkanal (9) vorgesehen ist. 6. Induction coil according to one of the preceding Ansprü¬ che, characterized in that a coolant-carrying cooling channel (9) is provided within a strand (6).
7. Induktionsspule nach einem der vorherigen Ansprü¬ che, dadurch gekennzeichnet, daß mehrere Litzen (6) ein Litzenbündel bilden, das von einer thermisch und gegen das Kühlmittel beständigen Isolation umgeben ist.7. induction coil according to one of the preceding Ansprü¬ che, characterized in that a plurality of strands (6) form a strand bundle, which is surrounded by a thermally and against the coolant insulation.
8. Induktionsspule nach Anspruch 7, dadurch gekenn¬ zeichnet, daß innerhalb eines Litzenbündels ein das Kühl¬ mittel führender Kühlkanal (9) vorgesehen ist.8. induction coil according to claim 7, characterized gekenn¬ characterized in that the coolant medium leading cooling channel (9) is provided within a strand bundle.
9. Induktionsspule nach einem der vorherigen Ansprü¬ che, dadurch gekennzeichnet, daß der Querschnitt der strangförmigen Hohlkörper (3,4) rechteckig ist.9. Induction coil according to one of the preceding Ansprü¬ che, characterized in that the cross section of the strand-shaped hollow body (3, 4) is rectangular.
10. Induktionsspule nach einem der vorherigen Ansprü- ehe, dadurch gekennzeichnet, daß an dem am Hohlleiter (3) angrenzenden Ende jedes die Litze(n) (6) aufnehmenden strangförmigen Hohlkörpers (4) an der Spulenaußenseite eine mit der (den) Litze(n) (6) elektrisch verbundene Stroman¬ schlußklemme (13) angebracht ist. 10. Induction coil according to one of the preceding claims, characterized in that at the end adjacent to the waveguide (3) each strand (4) receiving the strand (s) (6) receiving strand-shaped hollow body (4) on the outside of the coil with the strand (s) ( n) (6) electrically connected power connector (13) is attached.
EP95917895A 1994-06-13 1995-05-11 Low-loss induction coil for heating and/or melting metallic materials Expired - Lifetime EP0765592B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4420463 1994-06-13
DE4420463 1994-06-13
PCT/DE1995/000622 WO1995035014A1 (en) 1994-06-13 1995-05-11 Low-loss induction coil for heating and/or melting metallic materials

Publications (2)

Publication Number Publication Date
EP0765592A1 true EP0765592A1 (en) 1997-04-02
EP0765592B1 EP0765592B1 (en) 1998-04-22

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US (1) US5744784A (en)
EP (1) EP0765592B1 (en)
AT (1) ATE165488T1 (en)
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WO (1) WO1995035014A1 (en)

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US7323666B2 (en) 2003-12-08 2008-01-29 Saint-Gobain Performance Plastics Corporation Inductively heatable components
FR2972890B1 (en) * 2011-03-18 2014-07-25 Inst Polytechnique Grenoble INDUCTIVE SYSTEM THAT CAN SERVE COLD CUP
EP3401695A1 (en) 2017-05-08 2018-11-14 Koninklijke Philips N.V. Cooling a gradient coil of a magnetic resonance imaging system
CN109909383A (en) * 2019-03-12 2019-06-21 华电电力科学研究院有限公司 Method of relaxation d-axis water-cooled heating device

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DE523823C (en) * 1931-04-28 Hirsch Kupfer Und Messingwerke Coil for induction furnaces, consisting of a conductive and a heat dissipating part
US1839801A (en) * 1930-03-26 1932-01-05 Ajax Electrothermic Corp Electric induction furnace
US2457843A (en) * 1944-09-02 1949-01-04 Ohio Crankshaft Co Flexible conductor for induction heating
DE1095903B (en) * 1958-04-29 1960-12-29 Wild Barfield Electr Furnaces Electrical conductor
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See references of WO9535014A1 *

Also Published As

Publication number Publication date
DE59501998D1 (en) 1998-05-28
EP0765592B1 (en) 1998-04-22
ATE165488T1 (en) 1998-05-15
US5744784A (en) 1998-04-28
WO1995035014A1 (en) 1995-12-21

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