EP0081400A1 - Magnetische Induktionsheizvorrichtung für rechteckige Metallflachkörper, die sich in Längsrichtung bewegen - Google Patents

Magnetische Induktionsheizvorrichtung für rechteckige Metallflachkörper, die sich in Längsrichtung bewegen Download PDF

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Publication number
EP0081400A1
EP0081400A1 EP82401998A EP82401998A EP0081400A1 EP 0081400 A1 EP0081400 A1 EP 0081400A1 EP 82401998 A EP82401998 A EP 82401998A EP 82401998 A EP82401998 A EP 82401998A EP 0081400 A1 EP0081400 A1 EP 0081400A1
Authority
EP
European Patent Office
Prior art keywords
inductor
pole
axis
heating device
polar
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
EP82401998A
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English (en)
French (fr)
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EP0081400B1 (de
Inventor
Jean Maurice
Roger Travers
Jean-Paul Camus
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.)
Alstom SA
Original Assignee
Compagnie Electro Mecanique SA
Alstom SA
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Publication date
Application filed by Compagnie Electro Mecanique SA, Alstom SA filed Critical Compagnie Electro Mecanique SA
Publication of EP0081400A1 publication Critical patent/EP0081400A1/de
Application granted granted Critical
Publication of EP0081400B1 publication Critical patent/EP0081400B1/de
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
    • H05B6/102—Induction heating apparatus, other than furnaces, for specific applications for local heating of metal pieces the metal pieces being rotated while induction heated
    • 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
    • H05B6/365—Coil arrangements using supplementary conductive or ferromagnetic pieces

Definitions

  • the present invention relates to a device for heating by magnetic induction of flat rectangular metal products running in the direction of their length, of the type comprising at least one inductor capable of producing a magnetic field of constant intensity, but adjustable, oriented substantially perpendicular to a large face of the metal product to be heated, said inductor being rotatably mounted about an axis perpendicular to said large face of the metal product and comprising at least two magnetic poles having polar surfaces oriented towards said large face are parallel to these, and scanning an annular area when the inductor rotates.
  • the magnetic poles can be formed by permanent magnets, electromagnets or a combination of permanent magnets and electromagnets.
  • the inductor (s) can be placed outside a tunnel made of refractory material and permeable to the magnetic field, inside which pass the metallic products to be heated.
  • the previously known magnetic induction heating devices have been relatively little used until now for heating metallic products such as slabs or blanks, that is to say slabs before already undergoing several rolling passes in the roughing stands of a rolling mill, but not yet passed through the finishing stands of the rolling mill. Indeed, experience has shown that with previously known heating devices, it is difficult to obtain a temperature profile. regular erasure in the transverse direction of the metal products to be heated. This problem is further complicated if we consider that the metal products to be heated can have widths varying over a wide range of. values.
  • the present invention therefore aims to solve this problem by providing an improved device for magnetic induction heating to improve the uniformity of the heating in the transverse direction of the metal products running in the direction of their length, and this whatever the width of metal products within a given width range.
  • the magnetic induction heating device is characterized in that the pole surface of each pole has the shape of a curvilinear triangle having a vertex directed towards the axis of rotation of the inductor, two concave sides which are symmetrical with respect to a straight line passing through said vertex and perpendicular to said axis, and a convex side in an arc centered on said axis and whose radius of curvature is substantially equal to the outside radius of the annular zone swept by polar surfaces of the poles.
  • the conventional magnetic induction heating device which is shown diagrammatically in FIG. 1 and to which the present invention can be applied comprises, for example, two inductors 1 and 2 arranged respectively above and below the metal product 3 to be heated, for example a slab, facing the large faces of the slab 3, the latter being animated with a continuous movement in a direction perpendicular to the plane of the figure, that is to say in the direction of its length.
  • each of the two inductors comprises several magnetic poles, for example two magnetic poles 4.
  • the poles 4peuvent be constituted by permanent magnets, by p oles coils whose windings are supplied with direct current (solenoid), or by permanent magnets surrounded by windings which can be supplied with direct current.
  • the intensity of the direct current can be adjusted in a known manner in order to adjust the intensity of the magnetic field produced by the magnets and, consequently, the intensity of the heating produced by the eddy currents induced in the metallic product 3 to be heated.
  • the poles 4 have a section of circular shape (this shape corresponds to a maximum magnetic flux for a given length of conductor and therefore for given Joule losses in the case of wound poles).
  • At least one of the inductors 1 and 2 is rotated about the vertical axis z by known means not shown in Figure 1, the other inductor can be rotated synchronously either by the same means of drive, or by the magnetic field produced by the first inductor.
  • the speed of rotation of inductors 1 and 2 is usually clear much greater than the speed of advance of the metal product 3.
  • the pole surfaces of the poles 4 which are located opposite the large faces of the metal product 3 scan an annular zone 5 as shown in the figure 2. This zone 5 roughly corresponds to the zone of action of the inductors on the metal product 3 to be heated.
  • the heat energy which is brought to it by the Joule effect of the eddy currents induced in its mass would be relatively homogeneous in the annular zone 5.
  • the calorific energy provided at any point P located at a distance d from the longitudinal median axis of the product 3 is proportional to the length of stay of point P in the annular action zone 5 of the inductors, this length of stay being itself proportional to the length of the segment AB shown in FIG. 2.
  • the heating profile C which is obtained with such a heating device in the transverse direction of the metal product 3. As can be seen from the profile.
  • a heater such as that shown in Figure 1 and having dimensions such that the outside diameter of its annular action zone 5 corresponds substantially to the width of the metal product 3 to be heated does not not allow to obtain a homogeneous heating over the whole width of the product 3 while this one advances.
  • a heating device the dimensions of which are such that the outside diameter of its annular zone of action5 is significantly greater than the maximum width of the metallic products 3 to be heated, so as to operate in the middle part of the heating profile C. It is therefore necessary to use heating devices which are large in relation to the width of the metal products 3 to be heated. Under these conditions, it will be noted that the magnetic flux produced by the inductors is not fully used for heating, since it does not act on the metal product 3 to be heated when, during their rotation, the magnetic poles are found beyond the longitudinal sides of product 3, hence a lower yield.
  • the present invention overcomes this by -Providing a so'rait dimensions of the device such that the diameter of its area of action is only slightly greater than the maximum width of the products metal-li q ues moving heating , and making it possible to heat said products substantially homogeneously over their entire width with good efficiency.
  • this result can be obtained by using one or two inductors arranged like those of FIG. 1, but whose magnetic poles, constituted for example by electromagnets, have polar surfaces in the shape of a curvilinear triangle.
  • FIG. 3 shows by way of example, in front view, an inductor according to the present invention comprising four magnetic poles 4 of identical shapes and of alternating polarities.
  • Each magnetic pole 4 may comprise a magnetic core 6, for example of circular cross section, around which is arranged an excitation winding (not shown) supplied with direct current.
  • Each core 6 is provided with a pole shoe or pole piece 7 which is an integral part of the core 6 or which is fixed to the end of the core which is adjacent to the metal product to be heated.
  • Each pole shoe 7 has a planar pole surface parallel to one of the large faces of the metal product to be heated.
  • each bloom 7 has the shape of a curvilinear triangle which has a vertex 8 directed towards the axis of rotation z of the inductor, two concave sides 9 and 10, which are symmetrical with respect to a straight line passing through the apex 8 and perpendicular to the z axis, and a convex side 11 in an arc of a circle centered on the z axis and whose radius of curvature is substantially equal to the outside radius R of the annular zone 5 swept by the polar surfaces.
  • equation (1) The solution of equations (5) and (6) is provided by equation (1). Indeed, taking into account equations (1) and (3), equation (5) can be written: from where : from where : which gives E independent of d.
  • the variation in time of the magnetic field B seen by the point P, of polar coordinates r, ⁇ (figures 3 and 5) during the rotation of the induc tor can be represented by a succession of alternately positive and negative slots as shown in Figure 6.
  • Each slot corresponds to the passage of a pole 4 in front of point P and has a width which corresponds to the length of the polar arc ⁇ ( Figure 3) of each pole 4 at the distance r at which point P is located.
  • This waveform of the magnetic field B seen by point P can be broken down into Fourier series and expressed by the relation:
  • each of the pole shoes 7 the shape of a curvilinear triangle whose concave sides 9 and 10 are arcs of a circle having a profile which approaches the determined ideal profile.
  • the convex side 11 of which is an arc of a circle having a radius of curvature substantially equal to the outside radius of the annular zone swept by the poles 4, this outside radius itself being slightly larger than half the maximum width of the metal products to be heated.
  • each polar surface in the shape of a curvilinear triangle is preferably symmetrical with respect to the straight line passing through its apex 8 and through the center 0 of the rotating inductor, in order to obtain better balancing of the rotating masses.
  • the apex 8 of each curvilinear triangle is preferably curved to avoid leakage of magnetic flux between the poles 4 of opposite polarities.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Induction Heating (AREA)
EP82401998A 1981-11-13 1982-10-28 Magnetische Induktionsheizvorrichtung für rechteckige Metallflachkörper, die sich in Längsrichtung bewegen Expired EP0081400B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8121238A FR2516641A1 (fr) 1981-11-13 1981-11-13 Dispositif de chauffage par induction magnetique de produits metalliques rectangulaires plats defilant dans le sens de leur longueur
FR8121238 1981-11-13

Publications (2)

Publication Number Publication Date
EP0081400A1 true EP0081400A1 (de) 1983-06-15
EP0081400B1 EP0081400B1 (de) 1986-08-27

Family

ID=9263961

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82401998A Expired EP0081400B1 (de) 1981-11-13 1982-10-28 Magnetische Induktionsheizvorrichtung für rechteckige Metallflachkörper, die sich in Längsrichtung bewegen

Country Status (5)

Country Link
US (1) US4481397A (de)
EP (1) EP0081400B1 (de)
JP (1) JPS5894789A (de)
DE (1) DE3272924D1 (de)
FR (1) FR2516641A1 (de)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8304240A (nl) * 1983-12-08 1985-07-01 Skf Ind Trading & Dev Wiellager.
US4761527A (en) * 1985-10-04 1988-08-02 Mohr Glenn R Magnetic flux induction heating
US4856097A (en) * 1988-03-29 1989-08-08 Glenn Mohr Apparatus for induction heating of electrically conductive metal wire and strip
US5847370A (en) * 1990-06-04 1998-12-08 Nordson Corporation Can coating and curing system having focused induction heater using thin lamination cores
US5529703A (en) * 1990-06-04 1996-06-25 Nordson Corporation Induction dryer and magnetic separator
US5483042A (en) * 1990-06-04 1996-01-09 Nordson Corporation Magnetic separator
JPH06510622A (ja) 1990-11-30 1994-11-24 ヘロン　テクノロジーズ　インコーポレイテッド 誘導式乾燥装置及び磁気セパレータ
WO1993023970A1 (en) * 1992-05-08 1993-11-25 Heron Technologies, Inc. Induction dryer and magnetic separator
WO1995025416A1 (en) * 1994-03-16 1995-09-21 Larkden Pty. Limited Apparatus for eddy current heating, heat storage, electricity generation, and lens moulding process
FR2733553B1 (fr) * 1995-04-25 1997-07-11 Pem Sa Protection Electrolytiq Dispositif de contre-collage pour la solidarisation d'une bande metallique et d'une bande de materiau isolant
DE102008014165A1 (de) * 2008-03-14 2009-09-24 Ab Skf Vorrichtung zum Erwärmen und Verfahren zum Erwärmen
CN102037780B (zh) 2008-04-11 2014-08-27 迪姆肯公司 硬化轮齿和相似组件的永磁铁感应加热
US8993942B2 (en) 2010-10-11 2015-03-31 The Timken Company Apparatus for induction hardening
WO2012050552A1 (en) * 2010-10-11 2012-04-19 The Timken Company Apparatus for induction hardening

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR916287A (fr) * 1944-04-01 1946-12-02 Brown Procédé et dispositif pour le chauffage électrique de pièces métalliques
CH264034A (de) * 1947-10-28 1949-09-30 Bbc Brown Boveri & Cie Verfahren zum induktiven Erhitzen metallischer, plattenförmiger Werkstücke.
FR1387653A (fr) * 1964-03-31 1965-01-29 Four pour le chauffage de pièces métalliques
FR2473244A1 (fr) * 1980-01-04 1981-07-10 Cem Comp Electro Mec Procede et dispositif de chauffage electrique par induction de produits metalliques, utilisant des champs magnetiques pulses

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1036725A (en) * 1962-05-05 1966-07-20 Delapena & Sons Ltd Improvements in or relating to induction heating
CH416879A (de) * 1963-04-01 1966-07-15 Baermann Max Ofen zur Erwärmung von metallischen Teilen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR916287A (fr) * 1944-04-01 1946-12-02 Brown Procédé et dispositif pour le chauffage électrique de pièces métalliques
CH264034A (de) * 1947-10-28 1949-09-30 Bbc Brown Boveri & Cie Verfahren zum induktiven Erhitzen metallischer, plattenförmiger Werkstücke.
FR1387653A (fr) * 1964-03-31 1965-01-29 Four pour le chauffage de pièces métalliques
FR2473244A1 (fr) * 1980-01-04 1981-07-10 Cem Comp Electro Mec Procede et dispositif de chauffage electrique par induction de produits metalliques, utilisant des champs magnetiques pulses

Also Published As

Publication number Publication date
FR2516641A1 (fr) 1983-05-20
FR2516641B1 (de) 1984-01-27
JPS623554B2 (de) 1987-01-26
US4481397A (en) 1984-11-06
JPS5894789A (ja) 1983-06-06
EP0081400B1 (de) 1986-08-27
DE3272924D1 (en) 1986-10-02

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