0001]The present invention relates to induction heating and induction heating methods.
BACKGROUND
[0002]Conventionally, using an induction heating device, it can be continuously heated in the conductive plates, such as strip steel plate are performed. Induction heating apparatus, an alternating magnetic field generated from the coil (alternating magnetic field) is applied to the conductive plate, the Joule heat from the eddy current induced in the conductor plate is generated in the conductor plate by electromagnetic induction, this Joule heat it is to heat the conductive plate.
[0003]
　Such induction heating apparatus, there is a LF (Longitudinal Flux) type induction heating device and TF (Transverse Flux) of type induction heating device.
　Figure 12 is a diagram showing the configuration of the LF type induction heating apparatus. Specifically, FIG. 12 is a diagram showing a state in which overhead induction heating device 1200 LF formula from above. Incidentally, X-Y-Z coordinates shown in the figures shows the orientation relationship in each figure. The origin of X-Y-Z coordinates in the figures are the same (the origin of the X-Y-Z coordinates are not limited to the position shown in the figures). The conductive plate S of the strip to be heated is to be Tsuban in the positive direction along the Y-axis (the direction of the white arrows in FIG. 12). Above it is the same in other drawings.
[0004]
　Induction heating device 1200 LF type shown in FIG. 12 has a solenoid coil 1210. Solenoid coil 1210 is wound in the sheet passing direction substantially perpendicular direction of the conductor plate S so as to surround the strip-shaped conductive plate S. Therefore, the induction heating device 1200 LF type, and path of the current flowing through the solenoid coil 1210, the conductive plate S and is interlinked to be passing plate. Incidentally, an example of the direction of the current flowing through the solenoid coil 1210 is the direction of the arrows shown in the solenoid coil 1210 of FIG. 12. An alternating current flows to the solenoid coil 1210, substantially parallel to apply an alternating magnetic field in the longitudinal direction of the conductor plate S (that such magnetic longitudinal field (LF)). As the induction heating apparatus of such LF type, there is a technique described in Patent Document 1.
[0005]
　As described above, in the induction heating apparatus of the LF type passes through the interior of the solenoid coil in a state in which the conductor plate is interlinks. Therefore, if there is a conductive plate inside the solenoid coil, it is impossible to temporarily save the solenoid coil (so-called retraction). For example, the conductive plate at the upstream side of the induction heating device when broken, the conductor plate is Tsuban the induction heating apparatus while per Bata. Then, the conductor plate is in contact with the coil, the coil or the like is likely to be damaged. Also, often the coil itself becomes an obstacle of restoring work when passing conductor plate line during operation resumed.
[0006]
　Therefore, Patent Document 2, a portion of the area of ​​the coil and the door portion, technology that allows opening and closing is disclosed the door unit relative to the coil body. Using the technique described in Patent Document 2, after opening the door unit relative to the coil body, by moving the coil in a horizontal direction, in the induction heating apparatus of the LF type allows retraction is.
[0007]
　Figure 13 is a diagram showing a configuration of a TF-type induction heating device. Specifically, FIG. 13 is a diagram showing a state in which overhead induction heating device 1300 of TF expression from above.
　As shown in FIG. 13, the induction heating device 1300 of TF expression, through the plate surface of the strip conductive plate S, placing two coils 1310 and 1320 to the upper and lower conductor plates S. Two coils 1310 and 1320 are wound in a direction substantially parallel to the plate surface of the conductive plate S. Therefore, the induction heating device 1300 of TF expression, a path of current flowing through the two coils 1310 and 1320, and the conductive plate S which is passing plate not interlinked. Incidentally, an example of the direction of the current flowing through the coil 1310 and 1320 is the direction of the arrows shown in the coil 1310 and 1320 in FIG. 13. The two coils 1310, 1320, an alternating current flows in the same direction, (that such a magnetic field transverse magnetic (TF)) which substantially perpendicularly to apply an alternating magnetic field to the plate surface of the conductive plate S. In this case, an alternating magnetic field in the same direction are generated from the coil 1310 and 1320. The higher the horizontal magnetic field is large, it is possible to heat the conductive plate S to a high temperature.
[0008]
　Further, Patent Document 3, the two single-turn induction heating coil disposed to sandwich the conductor plate, only the coil width of a technique of shifting the sheet passing direction of the conductor plate is disclosed. Two single-turn induction heating coil described in Patent Document 3 has the same function as coil 1310, 1320. However, as described above, the direction of the alternating current applied to the coil 1310 and 1320 are the same. On the other hand, the direction of the alternating current applied to the two single-turn induction heating coil described in Patent Document 3 is reversed. Two single-turn induction heating coil, only the coil width of, by shifting the sheet passing direction of the conductive plate, an eddy current due to the horizontal magnetic field from the two single-turn induction heating coil to generate to the conductive plate is offset to suppress is that is.
[0009]
　Further, in the induction heating apparatus of TF expression, the end portion in the width direction of the conductive plate S (in the following description, the portion referred to as an edge portion as appropriate) an eddy current is concentrated on. Therefore, the said edge portion is overheated is common. Therefore, the induction heating apparatus of TF expression, as shown in FIG. 13, a position between the coils 1310 and 1320 and the conductive plate S, the conductor plates 1330 ~ at a position opposed to both edges of the conductive plate S it has been practiced to place a 1360 (see Patent Document 4).
[0010]
　Further, Patent Document 5, instead of the conductive plate, a technique for disposing the coil is disclosed. Via the conductor plate to place the primary coil to the upper and lower conductor plates. The primary coil is a heating coil, having the same function as coil 1310, 1320. Providing a plurality of secondary coils between the conductive plate and the primary coil. A plurality of secondary coils of the primary magnetic flux generated from the primary coil, weakening the primary flux of the edge portion near the conductive plate has a role of reducing the eddy current itself flowing through the conductor plate. It has a plurality of secondary coils to be able to move along the plate surface direction of the conductive plate.
CITATION
Patent Document
[0011]
Patent Document 1: JP-A-7-153560 JP
Patent Document 2: JP-A 6-88194 Patent Publication
Patent Document 3: JP 2007-324009 Patent Publication
Patent Document 4: JP 4959651 JP
Patent Document 5: JP 2007-122924 No.
Non-patent literature
[0012]
Non-Patent Document 1: momentum ShigeruJiro al., "Nature and frequency of the electrical heating", electric heating, Nihonden'netsu Association, 1992, No. 62, p. 6-7
Summary of the Invention
Problems that the Invention is to Solve
[0013]
　However, the technique described in Patent Document 2, a large workload for maintenance. For example, when the door portion and the coil body is not in uniform contact, current density or to increase the contact area between the door portion and the coil body, a discharge between the door portion and the coil body or place. Then, there is a fear that interruptions or door portion and the coil body of the operation will melt partially. Therefore, frequency of maintenance in order to stabilize the contact state of the door portion and the coil body is increased, to inhibit operation. Further, the induction heating apparatus described in Patent Document 2, for example, when applied to the plating line, there is a risk that the vapor from the plating bath remain in the contact portion between the door portion and the coil body. When steam is cooled in this state, the metal constituting the plating bath is attached to the contact portion between the door portion and the coil body, may cause discharge trouble. Therefore, it is necessary to maintenance work for removing such metal.
[0014]
　Meanwhile, in the technique described in Patent Documents 3 to 5, in order to prevent excessive heating of the edge portion, it is necessary to add another member (the conductive plate and the secondary coil) and the heating coil. Therefore, the structure of the induction heating device becomes complicated. Further, in the technique described in Patent Document 5, according to the plate width of the conductive plate to be heated, it is necessary to move the plurality of secondary coils. Therefore, it becomes more that complex mechanisms are added in order to move the plurality of secondary coils are common.
[0015]
　The present invention has been made in view of the problems described above, without adding a special configuration, temporarily and be made as uniform as possible a temperature distribution in the width direction of the conductive plate, the coil and to provide an induction heating device which realizes both the be retracted into.
Means for Solving the Problems
[0016]
　Induction heating apparatus of the present invention is an induction heating apparatus for induction heating of the conductor plate in the plate passage, and a first coil for generating a magnetic field in the thickness direction of the conductive plate by alternating current flows, an alternating current and a second coil for generating a magnetic field in the thickness direction of the conductive plate by the flow, the said second coil is first coil, positioned so as to sandwich the conductor plate, the first coil and the second coil, the position in the sheet passing direction of the conductor plate is substantially the same, by the alternating current, mutually opposite from said first coil and said second coil in the thickness direction of the conductor plate to generate a magnetic field of the magnetic field of the opposite direction to generate eddy currents inside the conductor plate, characterized by induction heating the conductor plate by the eddy current.
　Induction heating method of the present invention includes a first coil for generating a magnetic field in the thickness direction of the conductive plate by alternating current flows, the second to generate a magnetic field in the thickness direction of the conductive plate by alternating current flows has a coil, wherein the first coil and the second coil, the conductor plate positioned so as to sandwich the first coil and the second coil, strip passing substantially the position in the direction of the conductor plate an induction heating method for induction heating of the conductor plate in the passing plate using an induction heating apparatus is the same, by the alternating current, in the thickness direction of the conductor plate from the first coil and the second coil mutually to generate a magnetic field opposite to, the magnetic field of the opposite direction to generate eddy currents inside the conductor plate, characterized by induction heating the conductor plate by the eddy current.
Effect of the invention
[0017]
　According to the present invention, without adding a special configuration, and that the as much as possible uniform temperature distribution in the width direction of the conductive plate, the induction heating to achieve both the be temporarily saving the coil it is possible to provide a device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018]
[1] Figure 1 is a diagram showing an example of a configuration of an induction heating system.
FIG. 2 is a diagram showing an example of a Y-Z cross section of the induction heating apparatus of the embodiment.
FIG. 3 is a diagram conceptually illustrating an example of the orientation of the magnetic field generated by the alternating current flows through the first coil and the second coil.
FIG. 4 is a magnetic field generated by the alternating current flows through the first coil and second coil is a diagram conceptually illustrating an example of a state in which enters the interior of the conductor plate.
[Figure 5A] Figure 5A, the eddy current based on the magnetic field generated by the first coil, an example of an eddy current when it is assumed that the eddy current based on the magnetic field generated by the second coil is present independently conceptually It illustrates the.
[Figure 5B] Figure 5B is a diagram conceptually illustrating an example of an eddy current generated inside the conductor plate.
FIG. 6 is a diagram showing an example of the distribution of the surface temperature of the conductive plate in the width direction.
[7] FIG. 7 is a diagram conceptually illustrating an example of the relationship between the position of the thickness direction of the conductive plate, the current density of the eddy current flowing in the conductor plate.
[8] FIG. 8 is a diagram showing a first modification of the configuration of an induction heating system.
[9] FIG. 9 is a diagram showing a second modification of the configuration of an induction heating system.
[10] FIG 10 is a diagram showing a third modification of the configuration of an induction heating system.
[11] FIG 11 is a diagram showing an example of a Y-Z cross section of the UF type induction heating apparatus of the third modification.
[12] FIG 12 is a diagram showing the configuration of the LF type induction heating apparatus.
[13] FIG 13 is a diagram showing a configuration of a TF-type induction heating device.
DESCRIPTION OF THE INVENTION
[0019]
　Hereinafter, with reference to the drawings, an embodiment of the present invention. In the drawings, for convenience and notation of convenience of explanation, showing a simplified optionally only the portion necessary for the description.
[0020]
　Figure 1 is a diagram showing an example of a configuration of an induction heating system. Specifically, FIG. 1 is a diagram showing a state in which overhead induction heating device 100 from above. Here, the induction heating apparatus 100 of the present embodiment, for representing in distinction from the LF type induction heating device and TF type induction heating device, called UF (Ulterior Flux) type induction heating device as required. As described later, the induction heating apparatus 100 of the present embodiment, the first coil 110 in the region there is no conductive plate S between the second coil 120, in spite of the generated magnetic field by an alternating, mutual the magnetic field of the offset to be applied so as to be invisible. Therefore, it was decided to called the method of the induction heating apparatus 100 of the present embodiment UF expression.
[0021]
　Conductive plate S is, for example, steel. However, the conductive plate S is not limited to the steel sheet. The conductive plate such as a metal plate, a metal plate or a ferromagnetic nonmagnetic can be heat target. Be plated on the surface of the metal plate, it may be laminated a plurality of metal plates. The thickness of the conductor plate S is not particularly limited. For example, it can be 1 [mm] conductive plate of a thickness less than the (thin) to be heated. The direction of Y-axis in FIG. 1 is not particularly limited, for example, be a direction parallel to the ground, may be a direction perpendicular to the ground.
[0022]
　In Figure 1, the induction heating system, having an induction heating apparatus 100 of the UF type and AC power supply 200.
　Induction heating apparatus 100 of the UF type includes a first coil 110, a second coil 120, the first core 130, and a second core 140. Further, the first coil 110 and second coil 120, the AC power supply 200 is electrically connected.
　A first coil 110 and the second coil 120, the material, shape, and size are the same coil. A first coil 110 and the second coil 120 is formed by, for example, metal such as copper.
[0023]
　The first coil 110 is a coil wound in a direction substantially parallel to the plate surface of the conductive plate S. The first coil 110 is surface formed at a portion to be wound the winding (so-called coil surface), and one surface of the two plate surfaces of the conductive plate S (surface), not in contact with the conductive plate S It is arranged to be substantially directly face at a distance so.
[0024]
　The second coil 120, like the first coil 110, a coil wound in a direction substantially parallel to the plate surface of the conductive plate S. The second coil 120 is surface formed at a portion to be wound the winding (so-called coil surface), and the other surface of the two plate surfaces of the conductive plate S (back surface), not in contact with the conductive plate S It is arranged to be substantially directly face at a distance so. Further, when viewed along the direction (Y-axis direction in the example shown in FIG. 1) passing plate direction of the conductor plate S, the upper end face and lower end face of the first coil 110 and second coil 120 is a plane. Furthermore, this surface is substantially parallel to the plate surface of the conductive plate S.
[0025]
　Further, the first coil 110 and second coil 120 is arranged substantially right opposite positions across the conductive plate S. In other words, the position of the first coil 110 Y-axis direction of the second coil 120 (the sheet passing direction of the conductor plate S) is substantially the same. In the example shown in FIG. 1, the distance between the first coil 110 and the conductor plate S, the distance between the second coil 120 and the conductor plate S, it is assumed the same. Further, in the example shown in FIG. 1, a first coil 110 winding number of the second coil 120 are both 1 [times]. In the example shown this way in Fig. 1, a first coil 110 of the second coil 120, the position other than the position in the Z axis direction is substantially the same position. The first coil 110, 120 can be implemented with the same configuration as the coils 1310 and 1320 shown in FIG. 13.
[0026]
　Figure 2 is a diagram showing an example of a Y-Z cross section of the induction heating apparatus 100 of the UF type. Y-Z cross section, the induction heating apparatus 100 of the UF type, along the sheet passing direction of the conductor plate S (Y-axis direction) and thickness direction (Z axis direction) and the determined face (Y-Z plane), it is a cross section when cut at the position of the center in the width direction of the conductive plate S (X axis direction).
　The first core 130 and second core 140, the material, shape, and size are the same core. The first core 130 and second core 140 is formed by, for example, a soft magnetic material such as ferrite. The first core 130 is arranged at a position where the magnetic path of the magnetic flux generated from the first coil 110. The second core 140 is disposed at a position where the magnetic path of the magnetic flux generated from the second coil 120.
[0027]
　In this embodiment, as shown in FIGS. 1 and 2, the first core 130, compared rectangular parallelepiped shape, the first coil 110, according to the shape of the region extending in the width direction (X axis direction) recess There having been formed shape. In the present embodiment, as shown in FIGS. 1 and 2, when the first coil 110 is disposed in the recess, the first coil 110, and the conductor plate S and the opposing surfaces of the first core 130, and the conductor plate S facing the surface, but so as to be substantially flush, the recess of the first core 130 is formed.
[0028]
　Similarly, the second core 140, compared rectangular parallelepiped shape, a shape having a concave portion formed to fit the shape of the region which extends in the second coil 120, in the width direction (X-axis direction). When the second coil 120 is arranged in the recess, the second coil 120, a surface facing the conductive plate S, the second core 140, substantially flush and a surface facing the conductive plate S so that the recess of the second core 140 is formed.
[0029]
　Incidentally, the magnetic field between the first core 130 and the conductor plate S, so that the magnetic field between the second core 140 and the conductor plate S are opposite to each other, thereby applying a magnetic field to the conductive plate S if the possible shapes of the first coil 110 and second coil 120 is not limited to the shape shown in FIG. For example, the first coil 110, and the conductor plate S and the opposing surfaces of the first core 130, and a conductor plate S and the opposing surfaces may not be substantially flush. The same is true for the second coil 120 and the second core 140.
　The insulating process is applied between the first coil 110 and the first core 130. Insulation processing is performed also between the second coil 120 and the second core 140.
[0030]
　In Figure 1, for convenience of notation, although not shown, as shown in FIG. 2, in the present embodiment, the first coil 110 and second coil 120 has a hollow shape. Specifically, in the example shown in FIG. 2, the first coil 110 and second coil 120, the shape of the cross section perpendicular to the direction of flow of the alternating current is a hollow rectangular. This hollow portion, the cooling water flows. The cooling water, can be a first coil 110 and second coil 120 and water-cooled, to suppress the heat generation of the first coil 110 and second coil 120 is increased.
[0031]
　Here, the conductive plate S, the entire region in the width direction (X axis direction) is Tsuban so as to be positioned between the first core 130 and second core 140. That is, the conductive plate S in a state where the end portion in the width direction (edge ​​portion), located on the inner side than the end portion in the width direction (X-axis direction) of the first core 130 and second core 140, first so as to pass between the coils 110 and the second coil 120. To be able to in this way, the induction heating apparatus 100 of the UF formula (first coil 110, second coil 120, the first core 130, second core 140) length in the width direction of the (X-axis direction) pre-defined.
[0032]
　Further, as shown in FIG. 1, in this embodiment, one end portion 111 of the first coil 110 is electrically connected to one terminal 201 of the two output terminals of the AC power source 200. The other end 112 of the first coil 110 is electrically connected to the other terminal 202 of the two output terminals of the AC power source 200.
　Also, of the two ends of the second coil 120, one end 121 which is positioned to face each other at the other end 112 and the Z-axis direction of the first coil 110, one of the two output terminals of the AC power supply 200 It is electrically connected to the terminal 201. Also, of the two ends of the second coil 120, the other end portion 122 which is positioned to face each other at one end 111 and the Z-axis direction of the first coil 110, the other two output terminals of the AC power supply 200 It is electrically connected to the terminal 202.
[0033]
　Thus, in the present embodiment, the first coil 110 and second coil 120, (as viewed from the AC power source 200) such that the winding directions of the first coil 110 and second coil 120 are opposite to each other to be connected in parallel to an AC power source 200.
　Therefore, when an alternating current is supplied from the AC power supply 200, as shown in FIG. 1, when viewed from the same viewpoint in (the same time of the alternating current flowing in a region facing each other of the first coil 110 and second coil 120 of) direction to each other are opposite to (see arrows shown within the first coil 110 and second coil 120 of FIG. 1).
[0034]
　Arrows shown within the first coil 110 and second coil 120 of FIG. 1, the induction heating apparatus 100 of the UF type, when looking down from above, the direction of the alternating current flowing through the first coil 110 is clockwise a (clockwise), indicating that the orientation of the alternating current flowing in the second coil 120 is counterclockwise (leftward).
　Here, from the AC power source 200, an alternating current flowing through the first coil 110 and second coil 120 are different only direction (when viewed from the same viewpoint at the same time), and size (at the same time), the frequency They are each the same. The waveform of the alternating current, for example, a sine wave. However, the waveform of the alternating current may be in the same waveform as not limited to a sine wave, it can be used in a general induction heater waveform.
[0035]
　In the following description, the "(at the same time) direction of the first ac current flowing in the mutually facing area of ​​the coil 110 and the second coil 120 ', if necessary," the first coil 110 and the second It referred to as direction "of the alternating current of the coil 120.
[0036]
　Figure 3 is a diagram conceptually illustrating an example of the orientation of the magnetic field generated by the alternating current flows through the first coil 110 and second coil 120. Also in FIG. 3, similarly to FIG. 1, not shown in the hollow portion of the first coil 110 and second coil 120. Further, in FIG. 3, shown as an example the orientation of the magnetic field in the case that the direction in alternating current of arrows the flow shown in the first coil 110 and second coil 120 of FIG. Further, for convenience of notation, FIG. 3, showing an thicker the thickness of the conductor plate S as compared to the other figures.
[0037]
　By alternating current flows through the first coil 110, in the region between the first core 130 and the conductor plate S, a direction generally perpendicular to the plate surface of the conductive plate S (i.e., thickness direction of the conductive plate S) magnetic field H1 is generated of. Similarly, by alternating current flows through the second coil 120, in the region between the second core 140 and the conductor plate S, a direction generally perpendicular to the plate surface of the conductive plate S (i.e., a plate of conductive plates S magnetic field H2 is generated in the thickness direction). In the present embodiment, since the reversed orientation of the alternating current flowing through the first coil 110 and second coil 120 to each other, as shown in FIG. 3, facing each other of the first core 130 and second core 140 direction of the magnetic field H1, H2 in the region becomes opposite to each other. At this time, eddy currents Ie1 on one surface of the conductive plate S (upper surface) flows eddy current Ie2 on the other surface (lower surface) is induced in opposite directions. Eddy current Ie1, Ie2 details of the FIG. 4 will be described later with reference to FIGS. 5A and 5B,.
[0038]
　Induction heating apparatus 100 also of UF type of the present embodiment, as in the induction heating device of TF expression described in the background, the first coil 110, a path of current flowing in the second coil 120, conductor plate is passing plate S and is not interlinked.
　However, in the induction heating apparatus of TF expression, the direction of the alternating current flowing through the coil 1310, 1320 in the same direction. Further, in the technique described in Patent Document 3, in order to eddy currents due to the horizontal magnetic field from the two single-turn induction heating coil to generate to the conductive plate from being canceled, the two single-turn induction heating coil only the coil width of shifts in the sheet passing direction of the conductor plate.
[0039]
　In contrast, in the present embodiment, as described above, the direction each other as well as in the opposite direction to the alternating current flowing through the first coil 110 and second coil 120, first coil 110 Y-axis of the second coil 120 substantially the same position in a direction (sheet passing direction of the conductor plate S). Was conceived in this way, the present inventors have found is due first found was the following findings this.
[0040]
　First, two identical coils, magnitude conduct the same alternating current in opposite directions, when brought into proximity of these two coils, since the magnetic field generated by the mutual coil size are the same and opposite directions It is canceled in most places.
　In the induction heating device of TF expression, flowing eddy current in the conductive plate by the magnetic field passing through the conductive plate to heat the conductive plate by the eddy current. In this case, in the induction heating apparatus of TF expression, the direction of the current flowing through the two coils are the same. Place the conductor plate between the two coils, the frequency of the current being used in the induction heating apparatus of the TF mode, the flow in the opposite direction to the two coils, the magnetic field generated by the coil is offset in the conductive plate It is.
[0041]
　Thus, eddy current is not generated in the conductor within the plate, the conductive plate is not inductively heated. In the induction heating device of TF expression by increasing the magnitude of the magnetic field generated by the two coils, it is possible to heat the conductive plate to a higher temperature. Therefore, by passing an alternating current to the said coils so as to cancel the magnetic field generated by the two coils, it leads to reducing the effects of TF-type induction heating device.
[0042]
　In contrast, in the technique described in Patent Document 3, the direction of the alternating current applied to the two single-turn induction heating coil is reversed. However, in the technique described in Patent Document 3, the two single-turn induction heating coil, only the coil width of shifts in the sheet passing direction of the conductor plate. In Patent Document 3, in order to prevent the eddy current generated in the conductor plate by the magnetic field from the two single-turn induction heating coil is canceled, is that employing such a configuration. Thus, the technique described in Patent Document 3, the two single-turn induction heating coil, when not shifted in the sheet passing direction of the conductive plate, an eddy current generated in the conductor plate by the magnetic field from the two single-turn induction heating coil it is intended to build on the spirit of being canceled. Then, as in the technique described in Patent Document 3, applying the two single-turn induction heating coil, only the coil width of, in the configuration of shifting the sheet passing direction of the conductive plate, the techniques described in Patent Documents 4 and 5 If you do not, overheating of the edge portion occurs. Further, the two single-turn induction heating coil is intended to assist the induction heating apparatus of the LF type, by itself, not capable of induction heating the conductive plate to the desired temperature.
[0043]
　In contrast, the present inventors have found that the first coil 110 in a state of being substantially the same positions in the first coil 110 Y-axis direction of the second coil 120 (the sheet passing direction of the conductor plate S) second coil 120 the conductive plate S is disposed between the, be reversed the direction of the alternating current flowing through the first coil 110 and second coil 120 to each other, the frequency of the alternating current flowing through the first coil 110 and second coil 120 by adjusting the, inside of the conductor plate S, ready for magnetic fields H1, H2 generated by the alternating current flows through the first coil 110 and second coil 120 is not canceled, an eddy current based on magnetic fields H1, H2 There was found to be generated in the conductor plate S.
[0044]
　4, the magnetic field H1, H2 generated by the alternating current flows through the first coil 110 and second coil 120 is a diagram conceptually illustrating an example of a state in which enters the interior of the conductor plate S.
　Distribution of current generated in the conductor by electromagnetic induction, has the property of biased to the surface by the skin effect, this tendency is stronger the higher the frequency. As described in Non-Patent Document 1 or the like, penetration depth of the current in the conductor (the surface of the conductor, depth to the point where the current density is reduced to 1 / e (= 0.368) of the surface) [delta] [m] is expressed by the following equation (1).
[0045]
[Number 1]

[0046]
　(1) In the formula, [rho, the conductor resistivity [Ω · m], ω is the angular frequency [rad / s] (= 2πf ), μ is the magnetic permeability of the conductor [H / m], mu s is , the relative permeability of the conductor [-], f is the frequency f [Hz]. Permeability mu (relative permeability mu s value of)
[0047]
　The present inventors, based on the equation (1), by adjusting the frequency of the alternating current applied to the first coil 110 and second coil 120 ((1) of f), a first coil 110 first 2 place the conductor plate S between the Y-axis direction in a state of being positioned in substantially the same in (sheet passing direction of the conductor plate S) and the first coil 110 and the second coil 120 of the coil 120, first coil 110 and be reversed the direction of the alternating current flowing through the second coil 120 to each other, magnetic field generated by the alternating current flows through the first coil 110 and second coil 120 has been found that it is not canceled in the conductive plate S .
[0048]
　Preferred range of the frequency of the alternating current applied to such a first coil 110 and second coil 120, the present inventors have found the following ranges. That is, the present inventors have found that a range satisfying the following equation (2), found that preferably define the frequency of the alternating current applied to the first coil 110 and second coil 120 ((1) of f) It was.
　δ ≦ d / 2 ··· (2 )
[0049]
　(2) In the equation, d is the thickness of the conductive plate S [m]. (2) As shown in equation penetration depth of the current in the conductor plate S [delta] is such that the following half of the plate thickness d [m] of the conductive plate S, the first coil 110 and second coil be determined the frequency of the alternating current applied to the 120, as shown in FIG. 4, the magnetic field H1, H2 generated by the alternating current flows through the first coil 110 and second coil 120, ranging from entering the conductor plate S There are separated. Accordingly, in the region where the magnetic field H1, H2 enters appear mutually opposite directions of the eddy current Ie1, Ie2 is separated separately. The eddy current Ie1, can be heated one side of the conductor plate S, the eddy current Ie2, it is possible to heat the other side of the conductor plate S. Incidentally, the direction of the eddy current Ie1, Ie2 shown in FIG. 4 is an example, as shown in FIG. 5B to be described later, the direction of the eddy current Ie1, Ie2 is also the area of ​​direction and opposite that shown in FIG.
[0050]
　On the other hand, the upper limit of the frequency of the alternating current applied to the first coil 110 and second coil 120 is not particularly limited and is set appropriately in accordance with the application etc.. For example, if you want to only uniformly induction heating can be the entire interior of the conductor plate S is in a range satisfying the formula (1) may be selected as low frequency as possible. On the other hand, when it is desired to heat only the region close to the surface of the conductive plate S in accordance with the thickness from the surface of the area to be heated, as a range to be the may be selected high frequency (heating, in the thickness direction from the surface coverage the smaller, may be selected higher frequency).
[0051]
　5A and 5B are diagrams illustrating an example of an eddy current generated inside the conductor plate S. Specifically, FIG. 5A, the eddy current based on the magnetic field H1 generated by the alternating current flows through the first coil 110, and the eddy current based on the magnetic field H2 generated by the alternating current flows through the second coil 120 is independently it is a diagram conceptually illustrating an example of an eddy current on the assumption that there was. 5B is a diagram conceptually illustrating an example of an eddy current generated inside the conductor plate S. 5A and 5B, of the conductive plate S, showing only the vicinity area in the interior of the induction heating apparatus 100 of the UF type (between the first coil 110 and second coil 120).
[0052]
　Here, 5A and 5B, shows an example of the eddy current generated when the alternating current in the direction shown in FIG. 1 flows to the first coil 110 and second coil 120. That is, the direction of the magnetic field H1 generated by the alternating current flows through the first coil 110 is the negative direction of the Z-axis. The direction of the magnetic field H2 generated by the alternating current flows through the second coil 120 is a positive direction of the Z-axis. Further, in FIGS. 5A and 5B, it is assumed that the flow through the (1) alternating current having a frequency f satisfying the equation first coil 110 and second coil 120.
[0053]
　That is, eddy currents I1 based on the magnetic field H1 generated by the alternating current flows through the first coil 110 flows in the direction of canceling the magnetic field H1 (see FIG. 5A). Further, the eddy current I2 based on magnetic field H2 generated by the alternating current flows through the second coil 120 flows in the direction of canceling the magnetic field H2 (see FIG. 5A). These eddy currents I1 and I2 are generated independently in response respectively to the magnetic field H1 and H2.
[0054]
　However, in FIG. 5A, in the region of the edge in the width direction of the conductive plate S (X axis direction) (the edge portion), the tip of the end portion (constituting the conductor plate S) not conductive is present (the end thickness portion of the section is also on the surface). Therefore, of the eddy currents I1, I2, eddy currents in this area is canceled out mingled with each other, eddy current does not flow in this region.
[0055]
　On the other hand, in FIG. 5A, in the regions away from the end portion in the width direction of the conductive plate S (X axis direction) (the edge portion), (constituting the conductor plate S) therearound conductor exists (sheet passing direction ( conductive plate S is present continuously in the Y-axis direction)). Therefore, of the eddy currents I1, I2, eddy currents in this area, remain separate, there without miscible with each other.
[0056]
　From the above, among the eddy currents I1, I2 shown in FIG. 5A, the eddy current actually generated in the conductor plate S is present in the vertical area (surface) in the sheet passing direction of the conductor plate S (Y-axis direction) only to become the eddy current. That is, the eddy current along the edge in the width direction of the conductive plate S (X axis direction) (the edge portion) is not generated. As a result, as shown in Figure 5B, in the sheet passing direction of the conductive plate S (Y-axis direction) perpendicular to the area (surface), eddy current Ie1 on one surface of the conductive plate S (upper surface), the other surface eddy current Ie2 to (lower surface) flows in opposite directions to each other, respectively. As a result, as shown in FIG. 5B, perpendicular to the sheet passing direction of the conductor plate S (Y-axis direction), an area of ​​the conductive plate S (plane), the sheet passing direction (Y-axis direction of the conductor plate S the two regions with a spacing in), eddy current Ie1 opposite to each other, Ie2 (loop) occurs.
[0057]
　As described above, the present inventors have found that when an alternating current flows in the opposite direction to each other with respect to the first coil 110 and second coil 120, similar to the induction heating device of TF expression, the first coil 110 and despite the second coil 120 to generate a magnetic field (lateral magnetic field) in a direction perpendicular to the plate surface of the conductive plate S, as with the induction heating device of the LF type, passing plate conductive plate S to obtain a finding that eddy currents Ie1, Ie2 flows in a direction (Y axis direction) perpendicular to the area (plane).
[0058]
　The eddy current Ie1, Ie2 does not flow along the end portion in the width direction of the conductive plate S (X axis direction) (the edge portion) in the longitudinal direction (Y-axis direction). Therefore, as in the TF-type induction heating device, the edge portion is not over-heating. Therefore, the temperature distribution in the width direction (X-axis direction) of the conductive plate S, can be made substantially uniform. Moreover, the direction of the eddy current Ie1, Ie2 flowing to the conductive plate S is opposite to each other. This induction heating device of the LF type, and two disposed on the sheet passing direction of the conductor plate S (Y-axis direction), opposite the direction of current to each other applied to the coil of the two LF-type induction heating device It becomes the eddy current equivalent to be generated if an. That is, a single induction heating apparatus, the two eddy current equivalent eddy current generated in the induction heating apparatus of the LF type can generate.
[0059]
　Meanwhile, in the technique described in Patent Document 3, the two single-turn induction heating coil, shifting the sheet passing direction of the conductor plate. Therefore, eddy currents I1, I2 shown in FIG. 5A will be present at different positions in the sheet passing direction of the conductor plate S (Y-axis direction). That is, in the technique described in Patent Document 3, an eddy current Ie1, Ie2 as shown in Figure 5B does not flow, eddy currents, the end portion in the width direction of the conductive plate S (X axis direction) (the edge portion) longitudinal It flows along the direction (Y axis direction). Therefore, as described above, in the technique described in Patent Document 3, overheating of an edge portion occurs.
[0060]
　The first coil 110 and second coil 120 can be implemented with the same coil as the TF type induction heating device. Therefore, as in the induction heating device of TF expression, for example, only by moving the first coil 110 and second coil 120, it is possible to temporarily save the induction heating apparatus 100 of the UF formula (retract).
[0061]
　As a method of retraction, for example, the following methods.
　As a first method, the induction heating apparatus 100 of the UF expression, until no facing the plate surface and mutual conductive plate S, a method of moving the like the first coil 110 and second coil 120 in the horizontal direction.
　Specifically, it is possible to move the first coil 110 and second coil 120 in the same direction. That is, to move the first coil 110 and second coil 120 in the positive direction or negative direction of the X axis.
[0062]
　It is also possible to move the first coil 110 and second coil 120 in different directions. That is, the first coil 110 moves in the negative direction of the X axis, moving the second coil 120 in the positive direction of the X axis. Also, by moving the first coil 110 in the positive direction along the X-axis, it may be moved a second coil 120 in the negative direction of the X axis.
　In the first method described above, it may be either by moving only one of the first coil 110 and second coil 120.
[0063]
　As a second method, the induction heating apparatus 100 of the UF expression, to a position there is no possibility to contact with the conductive plate S, and a method of moving the first coil 110 and second coil 120 in the vertical direction (height direction) It is.
　Specifically, the first coil 110 is moved in the positive direction of the Z-axis to move the second coil 120 in the negative direction of the Z-axis.
　In the second method described above, it may be either by moving only one of the first coil 110 and second coil 120.
[0064]
　As a third method, the induction heating apparatus 100 of the UF expression, until no facing the plate surface and mutual conductor plate S, the first coil 110 and second coil 120, the side connected to the AC power supply 200 a predetermined position as a rotation axis, there is a method of rotating the first coil 110 and second coil 120. The rotation of the first coil 110 and second coil 120 can be carried out in a horizontal plane (in the X-Y plane in FIG. 1). The direction of rotation axis of the case of the rotation in a horizontal plane (in the X-Y plane in FIG. 1) is in the direction of the Z-axis. The direction of rotation of the case of the rotation in a horizontal plane (in the X-Y plane in FIG. 1) may be the same in the first coil 110 and second coil 120, may be different. On the other hand, the rotation of the first coil 110 and second coil 120, can also be carried out in the vertical plane (the X-Z plane of FIG. 1). The direction of rotation axis of the case where in the vertical plane (the X-Z plane of FIG. 1) is in the direction of Y-axis. The direction of rotation in the case of performing in the vertical plane (the X-Z plane of FIG. 1) is a first coil 110 and second coil 120 may be a direction away from the conductor plate S, respectively. In the third method, it may be either rotated only one of the first coil 110 and second coil 120.
[0065]
　Other may be temporarily saved to (retract) the induction heating apparatus 100 of the UF type in a manner that combines at least two ways of the first method to third method described above.
　In case of the above manner to temporarily save the induction heating apparatus 100 of the UF formula (retract), the control device for moving the induction heating apparatus 100 of the UF type also included in the configuration of the induction heating system.
[0066]
　Figure 6 is a diagram showing an example (actually measured values) of the distribution of surface temperature of the conductive plate in the width direction (X-axis direction). We used the steel as a conductor plate. 6, the distance from the center, as measured along the width direction (X-axis direction) of the steel sheet, the distance from the position of the center in the width direction of the steel sheet (X-axis direction). 6, the position of the center in the width direction of the steel sheet (X-axis direction) and 0 (zero). Also, FIG. 6 shows only the half of the region of the width direction of the steel sheet (X-axis direction).
[0067]
　The present inventors have found that, in the case where the reverse as in the present embodiment the direction of the alternating current applied to the first coil 110 and second coil 120, the direction of the alternating current applied to the first coil 110 and second coil 120 It was performed to the case of the same orientation as in the TF-type induction heating device for each measurement of. Upon these measurements, the measurement condition other than the direction of the alternating current applied to the first coil 110 and second coil 120, and respectively the same.
[0068]
　Specific measurement conditions are as follows.
　Thickness of the steel sheet: 1.1 [mm]
　steel plate width: 1 [m]
　strip running speed: 55 [m / min]
　steel conductivity at the target heating temperature: 1.0 × 10 7 [S / m ]
　the effective magnetic permeability of the target heating temperature of the steel sheet: 80
　current: 10000 [aT]
　current frequency: 10 [kHz]
[0069]
　From the above, the (1) formula (at the target heating temperature of the steel sheet) is penetration depth δ of the current 0.18 [mm].
　6, graph 601 shows the result when the direction of the alternating current applied to the first coil 110 and second coil 120 in the opposite direction. Graph 602 shows the result when the direction of the alternating current applied to the first coil 110 and second coil 120 in the same. In either case, the center (position of the center in the width direction (X-axis direction)), the steel sheet surface temperature rose longitudinal 200 [° C.].
[0070]
　Further, when the direction of the alternating current applied to the first coil 110 and second coil 120 in the opposite direction, the steel sheet surface temperature deviation in the width direction (X axis direction) (a value obtained by subtracting the minimum value from the maximum value) 2 was [° C.] (see graph 601). On the other hand, when the direction of the alternating current applied to the first coil 110 and second coil 120 in the same, the steel sheet surface temperature at the end (edge ​​portion) in the width direction (X axis direction), much than other regions higher becomes, exceeds 1300 [° C.] (see graph 602).
[0071]
　In the present embodiment as described above, so that the position of the first coil 110 and the second coil 120 in the Y-axis direction (sheet passing direction of the conductor plate S) are substantially the same, the first coil via the conductor plate S 110 and is opposed to the second coil 120 to each other. Then, by flowing an alternating current of frequency f to be less than half the thickness d of the penetration depth δ is conductive plate S of the current, in the opposite direction to the first coil 110 and second coil 120, conductor in passing plate inductively heating the plate S.
[0072]
　Therefore, the induction heating apparatus 100 of the UF type can be constituted only by coils and the core. Therefore, as in the TF-type induction heating device, the need to provide a special structure such as a conductive plate and a secondary coil in order to suppress excessive heating of the end portion in the width direction of the conductive plate S (edge ​​portion) no. Further, there is no need to provide a special structure in order to suppress excessive heating of the end portion (edge ​​portion) in the width direction of the conductor plate S. Therefore, according to the width of the conductive plate S, it is not necessary to change the settings of the induction heating apparatus 100.
[0073]
　Further, the UF-type induction heating device 100, similar to the induction heating device of TF expression, to generate a magnetic field in a direction perpendicular to the plate surface of the conductive plate S. Accordingly, the first coil 110 and second coil 120 may be the same coil and the induction heating device of TF expression. Therefore, it is possible to be the induction heating apparatus 100 of the UF type, also easily temporarily saved without providing a mechanism for separating the coil (retract). Moreover, it is not necessary to provide a mechanism for separating the coils, it is possible to reduce the burden of the maintenance work of the coil. Thus, if someone condition of the current and frequency used, by diverting TF type induction heating device of the (coil and core), by passing a reverse current to the coil in the manner described above, the induction of UF formula it is possible to realize a heating apparatus 100. Therefore, when there is an induction heating apparatus of TF expression, without significantly changing its equipment, it is possible to realize the induction heating apparatus 100 of the UF type.
[0074]
　In the induction heating apparatus 100 of the UF type of the present embodiment as described above, it suppresses overheating of the ends (edges) in the width direction of the conductor plate S, or to temporarily save the coils (retracted) without adding a special configuration for, by a simple configuration, to realize the method comprising the as much as possible uniform temperature distribution in the width direction of the conductive plate S, both the be temporarily saving the coil be able to.
[0075]
　Further, the UF-type induction heating apparatus 100 of the present embodiment, in the region between the first core 130 and second core 140, the conductor plate S is present between the first core 130 and second core 140 in non region (region of the end portion in the width direction of the induction heating device 100 (X-axis direction)), with a size of the same orientation magnetic field in the opposite direction will occur. Thus, the magnetic field in the region is canceled.
　Therefore, the induction heating apparatus 100 of the UF type, it is possible to minimize the magnetic field leaking to the surroundings can be minimized even electromagnetic interference given to the surroundings.
[0076]
　In general, the induction heating device, if there is no conductive plate S is the load, and generates a strong magnetic field by the coil and core. Therefore, the inductance of the induction heating device becomes larger. Therefore, if begins to conduct alternating current to the coil, the voltage across the coil increases rapidly. Therefore, in the absence conductive plate S is, in order that the flow coil alternating current up to the rated current of the induction heating apparatus is not easy, it may not be possible to confirm the soundness of the power supply system in advance.
[0077]
　In contrast, in the induction heating apparatus 100 of the UF type of the present embodiment, in a region other than the region between the first coil 110 and second coil 120, the magnetic field disappears almost offset. Therefore, the inductance of the induction heating apparatus 100 of the UF type 0 near (zero), even in the absence conductor plate S is, current to the first coil 101 and second coil 120 to the rated current of the induction heating apparatus 100 of the UF formula it can flow. Therefore, it is possible to confirm the soundness of the power supply system in advance.
[0078]
　Further, the UF-type induction heating apparatus 100 of the present embodiment, even during the heating of the conductor plate S, than the typical induction heating apparatus, the inductance is small. Therefore, compared to a general induction heating device, it is possible to reduce the voltage applied across the coil (the first coil 110 and second coil 120). Therefore, it is possible to suppress the capacity of the AC power supply 200. Further, the burden of the insulation processing in the first coil 110 and second coil 120 is reduced. Further, it is possible to first coil 110 and second coil 120 can be inhibited troubles due to discharge.
[0079]
　Further, in the present embodiment, when viewed along the direction (Y-axis direction in the example shown in FIG. 1) passing plate direction of the conductor plate S, the upper surface and the lower end surface of the first coil 110 and second coil 120 plane It was. Further, when viewed along the sheet passing direction of the conductor plate S, the upper end face and lower end face of the first core 130 and second core 140 was also in a plane in accordance with the first coil 110 and second coil 120. Therefore, it is possible to increase the heating efficiency of the induction heating apparatus 100 of the UF type. Further, it is possible to perform sheet passage and retraction of the conductive plate S safely. Furthermore, in the region between the first core 130 and second core 140, it is possible to sufficiently cancel the magnetic field in the region where the conductor plate S is not present between the first core 130 and second core 140 .
[0080]
(Modification)
　In the present embodiment, as the penetration depth of the current in the conductor plate S [delta] becomes 1/2 times the plate thickness d [m] of the conductive plate S (= d / 2) or less, the first a case defining the frequency of the alternating current flowing through the coil 110 and the second coil 120 ((1) of f) has been described as an example. Thus, it is possible to enhance the heating efficiency of the induction heating apparatus 100 of the UF type preferred. However, as long as the can induction heating of the conductive plate S, the frequency of the alternating current applied to the first coil 110 and second coil 120, need not necessarily decide this way.
[0081]
　Figure 7 is a diagram conceptually illustrating an example of a relationship between the thickness direction of the position of the conductive plate S, and the current density of the eddy current Ie1, Ie2 flowing to the conductive plate S.
　Figure 4 as described with reference to, the magnetic field H1, eddy current Ie1 flows on one side of the conductive plate S (upper surface), the magnetic field H2, eddy currents on the other surface of the conductive plate S (lower surface) Ie2 There flowing eddy currents Ie1 and reverse (see left diagram of FIG. 7). Eddy current Ie1, penetration depth of Ie2 [delta] is, even in the thickness d of the conductive plate S, as shown on the left in FIG. 7, the current density of the eddy current Ie1, Ie2 is the thickness direction of the conductor plate S not constant in becomes smaller with increasing distance from the surface. Thus, as shown on the right in FIG. 7, a part of the eddy current Ie1, Ie2 is being canceled, the remaining portion is present without being canceled. Thus, for example, penetration depth of the current in the conductor plate S [delta] is such that the plate thickness d [m] or less of the conductive plate S (less than or) of AC current applied to the first coil 110 and second coil 120 frequency ((1) of f) may define. In other words, may be employed (1) in place of equation, [delta] ≦ d or [delta]