JP6406674B2 - Induction heating device - Google Patents

Description

  Embodiments described herein relate generally to an induction heating apparatus.

  In general, in a hot rolling line, a material to be heated is heated to a temperature that can be rolled in a heating furnace, roughly rolled by a roughing mill, and formed into a state called a rough bar. Furthermore, a product having a desired plate pressure and plate width is obtained by applying the formed rough bar to a finish rolling mill. In recent years, in such a hot rolling line, an induction heating device is generally used for the purpose of reducing the load on the rolling mill against the temperature drop that occurs during the period when the rough bar reaches the finishing mill. . In the induction heating apparatus, an edge heater is applied to raise the temperature at both edges of the coarse bar, and a bar heater is applied to raise the overall temperature of the coarse bar.

  These edge heaters and bar heaters have a heating coil and an iron core for heating the coarse bar. In edge heaters and bar heaters, a shield cover and a heat-resistant plate are provided in order to protect the heating coil and the iron core from radiant heat from the coarse bar, adhesion of scale, and entry of water for cooling. Inspection and maintenance are indispensable for the heating coil and the iron core. For this reason, the shield cover and the heat-resistant plate are configured to be detachable.

  In the bar heater, a technique is known in which an air purge nozzle that blows air in the direction of the coarse bar width of the opening of the heating coil that passes through the coarse bar is arranged to control the timing of air purge (Patent Document 1 and the like). By providing such an air purge mechanism, the scale adhered to or deposited on the heating coil of the bar heater is scattered.

  In addition, in the case of a structure in which the C-shaped iron core of the edge heater is vertically divided for maintenance or the like, a technique relating to a method for protecting the iron core against adhered scale or water is known (patent) Literature 2 etc.). In this technique, the upper iron core is configured to move with respect to the lower iron core, and the divided surfaces of the upper iron core and the lower iron core are insulated to suppress the progress of corrosion and the like.

  There are various scales, some of which are fluttering in the atmosphere, and water is also converted into water vapor in the atmosphere. In addition, because there are unique atmospheric gases (for example, sulfur oxide, hydrogen sulfide, chlorine, etc.) in the steelworks, the inside of the induction heating device is constantly exposed to these scale, water vapor, and atmospheric gases. ing. In the induction heating apparatus, there are not only heating coils and iron cores but also electrical products such as bus bars and capacitors as main circuit conductors. The capacitor is molded by the case in the main body, but the connection bus bar connected to the bus bar on the main circuit side remains exposed. Further, the bus bars installed as the main circuit conductors need to be close as much as possible to reduce the inductance, and for this purpose, they are installed in a state of being close to each other with an insulating sheet interposed therebetween. On such a wiring structure, there is a risk of sudden ground faults or dielectric breakdown due to bus bar corrosion or insulation failure. Therefore, it is difficult to say that if the heating coil and the iron core are protected as the induction heating device, the operation can be stably performed.

JP 2001-291578 A JP 2011-96558 A

  Embodiments provide an induction heating device that prevents bus bar corrosion, sudden ground faults and dielectric breakdown in advance of scale, water and atmospheric gas intrusion, and the like.

  The induction heating device according to the embodiment includes an induction coil, an AC power supply that supplies power to the induction coil, and an internal wiring that electrically connects the induction coil. The internal wiring is provided between a first bus bar including a portion extending in a first direction, a second bus bar arranged in parallel to the first bus bar, and the first bus bar and the first insulating plate. The first bus bar, the second bus bar, and the first insulating plate, each of which has a first insulating plate, a first portion, and a second portion, and extends in a second direction intersecting the first direction. And an insulating support member sandwiched between the first part and the second part. The first bus bar and the second bus bar have an insulating layer on the surface. The lengths of the first part and the second part in the second direction are longer than the lengths of the first bus bar and the second bus bar in the second direction. The area of the first insulating plate is larger than the area of the projection surface obtained by projecting the first portion and the second portion sandwiching the first insulating plate onto the surface of the first insulating plate. The length of the first insulating plate in the second direction is longer than the lengths of the first portion and the second portion in the second direction.

  In the present embodiment, since the insulating layers are provided on the surfaces of the first bus bar and the second bus bar, electrical insulation between the first bus bar and the second bus bar is ensured. Furthermore, in the embodiment, the first bus bar and the second bus bar are provided between the first bus bar and the second bus bar and have a first insulating plate having a larger area and a longer length than the support member. The creepage distance between the bus bars can be kept long. Accordingly, it is possible to prevent busbar corrosion, sudden ground faults and dielectric breakdown against scale, water and atmospheric gas intrusion, and the like.

It is a schematic diagram which illustrates the induction heating apparatus which concerns on 1st Embodiment. It is a perspective view which illustrates the A section of FIG. It is sectional drawing in CC of FIG. It is sectional drawing in DD of FIG. FIG. 5A is a perspective view illustrating a part of the induction heating device of the comparative example. FIG.5 (b) is sectional drawing in EE of Fig.5 (a). FIG.5 (c) is sectional drawing in FF of Fig.5 (a). It is a schematic diagram which illustrates a part of induction heating apparatus which concerns on 2nd Embodiment. It is a perspective view which illustrates some induction heating apparatuses concerning a 3rd embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones. Further, even when the same part is represented, the dimensions and ratios may be represented differently depending on the drawings.
In the present specification and drawings, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

(First embodiment)
FIG. 1 is a schematic view illustrating an induction heating device according to this embodiment.
FIG. 2 is a perspective view illustrating part A of FIG.
3 is a cross-sectional view taken along CC in FIG.
4 is a cross-sectional view taken along DD in FIG.
In the following description, a coordinate axis composed of an X axis and a Y axis parallel to the installation surface on which the induction heating device is installed, and a Z axis perpendicular to the X axis and the Y axis is used. The installation surface is, for example, a plant floor.
As shown in FIGS. 1 and 2, the induction heating apparatus of the present embodiment includes a heater 4 and an internal wiring 10. The heater 4 is electrically connected to the external connection terminal 7 by the internal wiring 10. The heater 4 is electrically connected to the AC power source 2 via the external wiring 3 connected to the external connection terminal 7. AC power supply 2 is supplied by, for example, an inverter device.

  The heater 4 functions as an induction coil by winding a coil 6 around an iron core 5. An alternating current is supplied to the coil 6 via the internal wiring 10. When an alternating current supplied from the alternating current power source 2 is passed, the coil 6 generates a magnetic field.

  In this example, the heater 4 is an edge heater, and the iron core 5 has a letter “C” shape. The core 5 is provided with a gap 5a, and the material to be rolled 50 is conveyed through the gap 5a. In this example, the material to be rolled 50 is conveyed in a direction along the Y axis. In the gap 5a, a magnetic field reaching the surface of the material to be rolled 50 is generated by the coil 6, and the material to be rolled 50 is heated by the eddy current generated by this magnetic field. In addition, it can be set as a bar heater by providing a coil so that the shape of an iron core may be extended | stretched in the width direction (X-axis direction) of the to-be-rolled material 50. FIG.

  The heater 4 is attached to the main body frame 8a. The main body frame 8a is made of metal in terms of strength and the like, and has conductivity. The internal wiring 10 drawn out from the coil 6 is fixed to the main body frame 8a by attachment means described later. The heater 4, the internal wiring 10, and the main body frame 8 a are housed in a metal housing 9. One end of the internal wiring 10 is connected to the external connection terminal 7, and the external connection terminal 7 is provided so as to be exposed to the outside from the housing 9. The external wiring 3 is connected to the external connection terminal 7. The housing 9 is opened at a position corresponding to the gap 5a, and the coil 6 and part of the iron core 5 are exposed from the opening.

  In this example, the internal wiring 10 is fixed to the main body frame 8a using the clamps 18 and 19 when extending in the Z-axis direction. The internal wiring 10 can be attached to the main body frame 8a not only when extending in the Z-axis direction but also when extending in any other direction.

  The internal wiring 10 includes a first bus bar 12, a second bus bar 14, an insulating sheet 16, an insulating plate 17, and clamps 18 and 19. One end of each of the first bus bar 12 and the second bus bar 14 is electrically connected to the external connection terminal 7. The other ends of the first bus bar 12 and the second bus bar 14 are electrically connected to the heater 4.

  The first bus bar 12 and the second bus bar 14 supply AC current from the AC power source 2 to the coil 6 of the heater 4. The current flowing from the first bus bar 12 and the second bus bar 14 to the coil 6 generates a magnetic field passing through the gap 5 a of the heater 4.

  The first bus bar 12 and the second bus bar 14 are arranged close to each other in order to reduce inductance and suppress the influence of electromagnetic induction from other circuits and the like. On the other hand, since the first bus bar 12 and the second bus bar 14 are connected to different potentials, they are electrically insulated from each other.

  In this example, the first bus bar 12 and the second bus bar 14 extend from the connecting portion of the coil 6 toward the main body frame 8a in a direction substantially perpendicular to the XY plane, and bend substantially vertically near the main body frame 8a. And extending in a direction parallel to the Z-axis. The first bus bar 12 and the second bus bar 14 drawn out from the upper and lower coils 6 and 6 are connected to each other at a position where they are bent vertically. The first bus bar 12 and the second bus bar 14 are supported by the mounting surface 8b of the main body frame 8a at several places extending in a direction parallel to the Z axis. The position and direction supported by the main body frame 8a are not limited to this example, and can be arbitrarily set.

  As shown in FIGS. 3 and 4, each of the first bus bar 12 and the second bus bar 14 is a rectangle whose length (width) in the X-axis direction is W and whose length (thickness) in the Y-axis direction is T. It has a cross section. The width W is wider than the thickness T. The first bus bar 12 and the second bus bar 14 have portions extending in the Z-axis direction with the same width W. The length L (FIG. 1) in the Z direction of this portion is sufficiently longer than the width W and the thickness T.

  The first bus bar 12 includes four surfaces 12a to 12d that surround a rectangular cross section of W × T and extend in the Z-axis direction. The four surfaces are surfaces 12a and 12b substantially parallel to the X-axis direction and surfaces 12c and 12d substantially parallel to the Y-axis direction. The surface 12a is disposed to face the surface 14a of the second bus bar 14. The surface 12b is a surface opposite to the surface 12a, and the water cooling pipe 21 is provided on the surface 12b along the Z-axis direction. The water cooling pipes 21 are not limited to the case where two water cooling pipes 21 are provided along the length direction (Z-axis direction) of the first bus bar 12, and one or three or more water cooling pipes 21 may be provided. The water cooling pipe 21 is a hollow cylindrical member, and is formed of a metal such as copper having high thermal conductivity. The water-cooled pipe 21 is joined to the bus bar 12 on the surface 12b of the first bus bar 12 by a known joining technique such as an adhesive, soldering or welding. The water cooling pipe 21 cools the first bus bar 12 by flowing cooling water or other cooling medium through the hollow portion.

  An insulating layer 13 is provided on the surface of the water-cooled pipe 21 joined to the four surfaces 12 a to 12 d and the surface 12 b of the first bus bar 12. The insulating layer 13 is a layer having a substantially uniform thickness, and is formed by, for example, an electrostatic coating method using an insulating paint or the like.

  The second bus bar 14 is a wiring member having substantially the same shape as the first bus bar 12. That is, the second bus bar 14 has a rectangular cross section having a width W and a thickness T, and includes four surfaces 14a to 14d extending in the Z-axis direction. The four surfaces are composed of surfaces 14a and 14b substantially parallel to the X-axis direction and surfaces 14c and 14d substantially parallel to the Y-axis direction. The surface 14 a is disposed to face the surface 12 a of the first bus bar 12. The surface 14b is a surface opposite to the surface 14a, and the water cooling pipe 22 is provided on the surface 14b along the Z-axis direction. The water cooling pipe 22 is joined on the surface 14 b of the second bus bar 14. The water cooling pipe 22 cools the second bus bar 14 by flowing cooling water or other cooling medium through the hollow portion.

  An insulating layer 15 is provided on the surface of the water-cooled pipe 22 joined to the four surfaces 14 a to 14 d and the surface 14 b of the second bus bar 14. The insulating layer 15 is formed by electrostatic coating or the like as in the case of the first bus bar 12.

  The insulating sheet 16 is provided between the surface 12 a of the first bus bar 12 and the surface 14 a of the second bus bar 14. The insulating sheet 16 has a width Wi1 wider than the width W of the first bus bar 12 and the second bus bar 14. The insulating sheet 16 is provided along the direction in which the first bus bar 12 and the second bus bar 14 extend. The insulating sheet 16 is made of an electrically insulating material, and is an insulating sheet made of, for example, a polyester film or a polyimide film. Of course, mica or the like may be used as the insulating material. Preferably, the insulating sheet 16 is made of a material having low elasticity such that the thickness is reduced when stress is applied to the contact surface.

  Since the width Wi1 of the insulating sheet 16 is wider than the width W of the first bus bar 12 and the second bus bar 14, the surface 12c of the first bus bar 12, the surface 14d of the second bus bar 14, and the surface 12d of the first bus bar 12 And the creepage distance in the surface 14c of the 2nd bus bar 14 can be lengthened about (Wi-W) / 2, respectively.

  The insulating plate 17 is provided between the surface 12 a of the first bus bar 12 and the surface 14 a of the second bus bar 14. The insulating plate 17 is provided between the insulating sheet 16 and the second bus bar 14. Therefore, the insulating sheet 16 is provided between the first bus bar 12 and the insulating plate 17. The length Li of the insulating plate 17 in the X-axis direction is longer than the length Lc of the clamps 18 and 19 in the X-axis direction. The length (width) Wi2 of the insulating plate 17 in the Z-axis direction is longer than the length (width) Wc of the clamps 18 and 19 in the Z-axis direction. In other words, the area of the insulating plate 17 is larger than the area of the surfaces where the clamps 18 and 19 face each other. In other words, when the insulating plate 17 is clamped by the clamps 18 and 19, the peripheral edge of the insulating plate 17 extends from the outer periphery of the clamps 18 and 19 to the outside. That is, the peripheral edge portion of the insulating plate 17 protrudes from the outer periphery of the clamps 18 and 19. The creepage distance between the first bus bar 12 and the second bus bar 14 can be further increased by the length of the insulating plate 17 protruding from the clamps 18 and 19.

  The clamps 18 and 19 sandwich the first bus bar 12, the insulating sheet 16, the insulating plate 17, and the second bus bar 14 in this order by the two portions. As described above, the surface sandwiching the first bus bar 12, the insulating sheet 16, the insulating plate 17, and the second bus bar 14 has a substantially rectangular shape with a length Lc and a width Wc.

  The insulating plate 17 is not limited to being provided between the insulating sheet 16 and the second bus bar 14, and may be provided between the insulating sheet 16 and the first bus bar 12. In that case, the clamps 18 and 19 sandwich the first bus bar 12, the insulating plate 17, the insulating sheet 16, and the second bus bar 14 in this order.

  The clamp 18 includes a surface parallel to the XZ plane. A concave portion 18a is formed on this surface. The recess 18 a is provided on the surface 12 b side of the first bus bar 12. The recess 18a is provided continuously along the Z-axis direction, that is, the direction in which the first bus bar 12 extends. The length (depth) Dr in the Y-axis direction of the recess 18a is set slightly shorter than the total value of the thickness T of the first bus bar 12 and the diameter of the water-cooled pipe. Due to this dimension, when the clamp 18 holds the first bus bar 12, the insulating sheet 16, the insulating plate 17, and the second bus bar 14 together with the clamp 19, stress is generated in the clamping direction and these are applied to the clamps 18 and 19. Can be fixed.

  The clamp 19 includes a surface parallel to the XZ plane. A concave portion 19a is formed on this surface. Similar to the recess 18a, the recess 19a is provided on the surface 14b side of the second bus bar 14 along the Z-axis direction, that is, the direction in which the second bus bar 14 extends. The length (depth) Dr in the Y-axis direction of the recess 19a is the same as the depth Dr of the recess 18a. The depth Dr of the recess 19a is also set slightly shorter than the total value of the thickness T of the second bus bar 14 and the diameter of the water-cooled pipe 22.

  The clamps 18 and 19 are formed of an insulating material, for example, a synthetic resin having high heat resistance. The clamps 18 and 19 face the surfaces provided with the recesses 18a and 19a, respectively, and the first bus bar 12, the second bus bar 14, and the water cooling pipes 21 and 22 are accommodated in the recesses 18a and 19a, respectively. The bus bar 12, the second bus bar 14, the insulating sheet 16, and the insulating plate 17 are sandwiched.

  The clamps 18 and 19 sandwiching the first bus bar 12, the second bus bar 14, the insulating sheet 16, and the insulating plate 17 are attached to the main body frame 8a at one end in the X-axis direction. Attachment members 24 and 25 are used for attachment to the main body frame 8a. In this example, the mounting members 24 and 25 are L-shaped mounting brackets in an XY plan view. The attachment members 24 and 25 are formed of a metal material from the viewpoint of ensuring strength.

  The mounting member 24 is substantially parallel to the X axis, that is, a portion 24a including a surface along the surface of the clamp 18 opposite to the side where the recess 18a is formed, and substantially parallel to the Y axis, that is, the main body frame 8a. And a portion 24b including a surface along the mounting surface 8b. The portion 24b is bent in an L shape on the side opposite to the attachment surface of the portion 24a to the clamp 18. A mounting hole 24c penetrating in the Y-axis direction is opened on the surface of the portion 24a. A mounting hole 24d penetrating in the X-axis direction is also opened on the surface of the portion 24b.

  The mounting member 25 is substantially parallel to the X axis, that is, a portion 25a including a surface of the clamp 19 along a surface opposite to the side where the recess 19a is formed, and substantially parallel to the Y axis, that is, the main body frame 8a. And a portion 25b including a surface along the mounting surface 8b. The bending direction of the portion 25 b is opposite to the bending direction of the portion 24 b of the one attachment member 24. An attachment hole 25c penetrating in the Y-axis direction is opened on the surface of the portion 25a, and an attachment hole 25d penetrating in the X-axis direction is also opened on the surface of the portion 25b.

  The mounting holes 18c and 19c of the clamps 18 and 19 are opened through in the Y-axis direction at positions corresponding to the mounting holes 24c and 25c of the mounting members 24 and 25.

  Although not shown, holes for inserting the bolts 31a are also opened at corresponding positions of the insulating plate 17. The shaft of the bolt 31 a is inserted through the attachment member 24, the clamp 18, the insulating plate 17, the clamp 19, and the attachment member 25. A washer 31c and a nut 31b are attached to the shaft of the inserted bolt 31a.

  When the first bus bar 12, the insulating sheet 16, the insulating plate 17, and the second bus bar 14 are clamped by the clamps 18 and 19, they are applied to the surfaces of the first bus bar 12, the insulating sheet 16, the insulating plate 17 and the second bus bar 14. In order to equalize the stress to be applied, the mounting members 24 and 25 are provided with a mounting hole on the opposite side in the X-axis direction, that is, on the tip side of the clamps 18 and 19, 19 may be tightened.

  The attachment members 24 and 25 sandwiching the clamps 18 and 19 are attached to the main body frame 8a by attachment holes 24d and 25d opened in the portions 24b and 25b.

  Since the main body frame 8a is generally made of metal and has conductivity, it is preferably electrically insulated from the mounting members 24 and 25 having conductivity. An insulating plate 28 is provided between the attachment surfaces of the portions 24b and 25b attached to the main body frame 8a of the attachment members 24 and 25 and the attachment surface 8b of the main body frame 8a. The insulating plate 28 has an area larger than the area of the attachment surface of the clamps 18 and 19 and the portions 24b and 25b of the attachment members 24 and 25 to the main body frame 8a. Therefore, for example, scale or water adheres to the upper surfaces 18b, 19b of the clamps 18, 19, and the insulation resistance of the insulating layer 13 of the first bus bar 12 or the insulating layer 15 of the second bus bar 14 decreases due to deterioration or the like. Even if the energization path is generated by the scale, the mounting members 24 and 25 are electrically insulated from the main body frame 8a and do not substantially affect the insulation performance of the first bus bar 12 and the second bus bar 14. .

  Bolts and nuts are used for joining the mounting members 24 and 25 to the main body frame 8a. In the main body frame 8a, mounting holes 9a and 9b penetrating in the X-axis direction are opened at positions corresponding to the mounting holes 24d and 25d of the mounting members 24 and 25, respectively. Further, mounting holes penetrating in the X-axis direction are also opened at positions corresponding to the mounting holes 9a, 24d and 9b, 25d of the insulating plate 28. Metal bolts are used for the bolts 32a inserted from the mounting holes 9a to the mounting holes 24d and the bolts 33a inserted from the mounting holes 9b to the mounting holes 25d from the viewpoint of securing strength. Insulating washers 32d and 33d are inserted through the heads of the shafts of the bolts 32a and 33a so that the mounting members 24 and 25 and the main body frame 8a are not electrically connected by the bolts. The insulating tubes 32e and 33e are inserted through the shafts 32a and 33a. In addition to normal washers 32c and 33c, insulating washers 32f and 33f are inserted on the nuts 32b and 33b side. Therefore, the main body frame 8a, the mounting members 24 and 25, and the bolts 32a and 33a are electrically insulated by the insulating washers 32d and 33d, the insulating tubes 32e and 33e, and the insulating washers 32f and 33f, respectively.

  In this way, each bolt is inserted through the mounting hole, and the mounting members 24 and 25 are fixed to the main body frame 8a.

The operation and effect of the induction heating device of the present embodiment will be described in comparison with the induction heating device of the comparative example.
FIG. 5A is a perspective view illustrating a part of the induction heating device of the comparative example. FIG.5 (b) is sectional drawing in EE of Fig.5 (a). FIG.5 (c) is sectional drawing in FF of Fig.5 (a).
As shown in FIGS. 5A to 5C, the internal wiring 110 of the comparative example includes a first bus bar 112, a second bus bar 114, and an insulating sheet 116. The insulating sheet 116 is provided between the first bus bar 112 and the second bus bar 114. The length (width) of the insulating sheet 116 in the X-axis direction is wider than the width of the first bus bar 112 and the second bus bar 114. The first bus bar 112 and the second bus bar 114 are not provided with an insulating layer on the surface, and are not provided with an insulating plate having an area larger than the area of the opposing surfaces of the clamps 118 and 119.

  Therefore, in the internal wiring of the comparative example, the creepage distance between the first bus bar 112 and the second bus bar 114 is determined by the length of the portion where the insulating sheet 116 protrudes from the first bus bar 112 and the second bus bar 114. The When the width of the first bus bar 112 and the second bus bar 114 is W ′, the width of the insulating sheet 116 is Wi ′, and the insulating sheet 116 protrudes uniformly from both sides of the first bus bar 112 and the second bus bar 114 The creepage distance is (Wi′−W ′) / 2 × 2 + Ti ′ = Wi ′ + Ti ′. Ti ′ is the thickness of the insulating sheet 116. That is, in the internal wiring 110 of the induction heating device of the comparative example, the creepage distance between the first bus bar 112 and the second bus bar 114 is determined by the width Wi ′ of the insulating sheet 116, and the energization path due to the accumulation of scale or the like It will be decided how easy it is.

  In the internal wiring 110 of the comparative example, when the clamps 118 and 119 are attached to the main body frame 108a, bolts are inserted into the metal attachment members 124 and 125 and tightened with nuts. Therefore, the attachment members 124 and 125 are at the same potential as the main body frame 108a. As indicated by the solid line arrows in FIG. 5B, the creeping distance between the first bus bar 112 and the second bus bar 114 and the main body frame 108a is the shortest distance between them.

  In the internal wiring 10 of the induction heating apparatus of the present embodiment, the first bus bar 12 and the second bus bar 14 include insulating layers 13 and 15 on the surfaces, respectively. Therefore, the first bus bar 12 and the second bus bar 14 are electrically insulated from each other, and the concept of creepage distance does not occur between the first bus bar 12 and the second bus bar 14. Therefore, even if a scale or the like is deposited around the first bus bar 12 and the second bus bar 14, it does not become an energization path, and reliability is maintained.

  As described above, since the induction heating device is required to operate in a severe environment of high temperature and humidity, the insulating layers 13 and 15 formed on the surfaces of the first bus bar 12 and the second bus bar 14 are deteriorated. It is conceivable that the insulation performance is lowered by the same. However, in the internal wiring 10 of the induction heating device of the present embodiment, an insulating plate 17 having a larger area than the opposed surfaces of the clamps 18 and 19 is provided between the first bus bar 12 and the second bus bar 14. . Therefore, the creepage distance between the 1st bus bar 12 and the 2nd bus bar 12 is extended like the arrow of the broken line of FIG. More specifically, the length Li of the insulating plate 17 is sufficiently longer than the length Lc of the clamps 18 and 19. For example, when the length of the insulating plate 17 protruding from the first bus bar 12 and the second bus bar 14 is Le, the creepage distance between the first bus bar 12 and the second bus bar 14 is 2 × Le + Ti. Become. Here, Ti is the total thickness of the insulating sheet 16 and the insulating plate 17. Since Le can be sufficiently longer than (Wi'-W ') / 2 in the comparative example, the creepage distance between the first bus bar 12 and the second bus bar 14 can be extended.

  Furthermore, since a scale or the like is more likely to be deposited on a surface that is nearly parallel to the installation surface of the induction heating device, an energization path is easily formed. In other words, the larger the angle from the installation surface of the induction heating device, the more difficult it is to drop and deposit scales and the like, and thus the energization path is less likely to be formed. As shown in FIG. 1, when the first bus bar 12 and the second bus bar 14 are arranged so as to be substantially perpendicular to the installation surface of the induction heating device, the upper surfaces 18 b and 19 b of the clamps 18 and 19 are Since it is almost horizontal with respect to the installation surface, scales and the like are easily deposited. In the internal wiring 10 of the induction heating device of the present embodiment, the insulating plate 17 has an area larger than the area of the opposing surfaces of the clamps 18 and 19. That is, the peripheral edge portion of the insulating plate 17 protrudes outward from the outer periphery of the clamps 18 and 19. The protruding portion has no surface parallel to the installation surface of the induction heating device, and the scale or the like falls down without being deposited. Therefore, a portion where the insulating plate 17 protrudes from the outer periphery of the clamps 18 and 19 is less likely to form an energization path, and electrical insulation between the first bus bar 12 and the second bus bar 14 is maintained.

  Further, in the internal wiring 10 of the induction heating device of the present embodiment, since the insulating plate 28 is provided between the attachment members 24 and 25 and the main body frame 8a, the attachment members 24 and 25 are separated from the main body frame 8a. It is electrically insulated. Therefore, even if a part of the energization path may be formed at the position of the straight arrow indicated by the broken line in FIG. 3, the position of the arrow does not become a creepage distance. Therefore, the insulation resistance between the first bus bar 12 and the second bus bar 14 and the mounting members 24 and 25 can be sufficiently increased.

  As described above, in the induction heating device of the present embodiment, electrical insulation is ensured between the first bus bar 12 and the second bus bar 14 by the insulating layers 13 and 15. Even when the insulating layers 13 and 15 are deteriorated, in the induction heating apparatus, the creeping distance between the first bus bar 12 and the second bus bar 14 is sufficiently long, and an energization path due to deposition of scales or the like is formed. Hateful. The energization path between the first bus bar 12 and the second bus bar 14 and the main body frame 8a is also sufficiently long. Therefore, an induction heating device having high insulation performance is realized by making it difficult to form a current-carrying path due to high temperature and humidity, scale, or the like.

  In the above description, the attachment to the main body frame 8a when the internal wiring 10 extends in the Z-axis direction has been described. However, the above-described structure is not limited to the case where the internal wiring 10 extends in the Z-axis direction. When the internal wiring 10 extends in the X-axis direction or the Y-axis direction, one of the first bus bar 12 or the second bus bar 14 is located above the installation surface, and the other is located below the installation surface. Such an attachment position can be obtained. In such a case, scales or the like may be deposited on the upper bus bar or the insulating plate, but even if scales or the like adhere to the lower bus bar or the insulating plate, they are immediately dropped and are not easily deposited. . That is, in such a case, it is difficult to form an energization path between the first bus bar 12 and the second bus bar 14 due to adhesion or accumulation of scale or the like. Therefore, it is considered that there are many cases where there is no problem in insulation performance even if the structure is not the same as the structure in the present embodiment. However, depending on the installation environment of the induction heating device, the internal wiring may be exposed to a corrosive atmosphere gas or the like. In such a case, there is a possibility that the corrosion of the bus bar will proceed, or conductive fine particles may adhere to the side surface or the lower side of the insulating plate. High insulation performance can be maintained.

(Second Embodiment)
In the induction heating apparatus of this embodiment, a mechanism for positively removing a current-carrying path forming substance such as a scale that adheres or accumulates is added.
FIG. 6 is a schematic view illustrating the induction heating device of this embodiment.
As shown in FIG. 6, the induction heating apparatus of the present embodiment further includes an air purge mechanism 60. The air purge mechanism 60 includes a nozzle 61 and a pipe 62. The air purge mechanism 60 is provided above the clamps 18 and 19 of the internal wiring 10 (on the positive side in the Z direction). The air purge mechanism 60 is fixed by an attachment member 63 above the main body frame 8 a to which the clamps 18 and 19 are attached by attachment members 24 and 25.

  The nozzle 61 is provided on the surface of the pipe 62 and is fluidly connected to the inside of the pipe 62. Air (air) or an inert gas is supplied to the pipe 62 from a gas supply source (not shown), and the air supplied through the pipe 62 is ejected from the nozzle 61. The air jet direction of the nozzle 61 is set so as to face the upper surface 18 b of the clamp 18. Although not shown, air is also blown to the upper surface 19 b of the clamp 19.

  Since the upper surfaces 18b and 19b of the clamps 18 and 19 are substantially parallel to the installation surface of the induction heating device, scales and the like adhere to the upper surfaces 18b and 19b and are easily deposited. The air purge mechanism 60 supplies air to the pipe 62 and, for example, periodically blows air 64 from the nozzle 61 to the upper surfaces 18 b and 19 b of the clamps 18 and 19. The scale 64 is blown off by the blown air 64 to prevent accumulation of the scale and the like.

The operation and effect of the induction heating device of this embodiment will be described.
The induction heating apparatus according to the present embodiment includes an air purge mechanism 60 including a nozzle 61 that ejects air toward the upper surfaces 18b and 19b of the clamps 18 and 19. Therefore, scales and the like adhering to the upper surfaces 18b and 19b substantially parallel to the installation surface of the induction heating device can be removed, so that the formation of an energization path by the scales can be suppressed. Even in the case of a wiring structure having a composite insulating structure as in the case of the first embodiment described above, when deterioration or the like occurs due to corrosion of an insulating layer or an insulating plate under a severe operating environment. This reduces the insulation resistance and affects the operation of the induction heating device. In the induction heating device of the present embodiment, the adhesion itself of the scale and the like can be suppressed in advance, so that the reliability of the induction heating device can be improved and it can contribute to continuous operation.

(Third embodiment)
FIG. 7 is a perspective view illustrating a part of the induction heating device of the present embodiment.
As described above, in order to maintain the reliability of the operation of the induction heating apparatus in a harsh environment such as a steel plant, it is necessary to positively ensure insulation performance. Since such an environment does not occur uniformly in the plant, it is effective to set, for example, the installation position of the air purge mechanism 60 and the operation frequency of the air purge mechanism 60 according to the degree of severity of the environment. It is. The induction heating device of this embodiment further includes an environment measuring device 70. The environment measuring instrument 70 collects objective data for quantitatively grasping the environment where the induction heating apparatus is installed.

  As shown in FIG. 7, the environment measuring instrument 70 includes a deposit receiving box 71, a filter paper 72, a temperature and humidity meter 73, and a copper plate 74. The deposit receiving box 71, the filter paper 72, the temperature / humidity meter 73, and the copper plate 74 are mounted on the installation plate 75, respectively. The environment measuring device 70 is disposed at a specific location of the induction heating device. The specific location is, for example, in the vicinity of the location where the clamps 18 and 19 are fixed to the main body frame 8a. It goes without saying that the environment measuring device 70 can be installed in any place including the inside and the periphery of the induction heating apparatus.

  The deposit receiving box 71 is a rectangular parallelepiped container having an upper opening, and collects solids such as a scale and dust from the atmosphere of the installation location through the opening.

  The filter paper 72 is installed to adsorb the atmospheric gas present in the induction heating device and measure the adsorbed gas.

  The thermohygrometer 73 is used to measure the temperature and humidity conditions in the induction heating apparatus. In this example, temperature and humidity are periodically measured, and the measurement results are stored in an internal (not shown) memory unit.

  The copper plate 74 is installed to acquire and measure a product generated by a substance or the like attached to the surface of the copper plate 74.

The operation and effect of the induction heating device of this embodiment will be described.
In the induction heating apparatus of this embodiment, since the environment measuring device 70 is provided, it is possible to quantitatively grasp the severity of the environment in which the induction heating apparatus is installed. Since the environment measuring instrument 70 includes the deposit receiving box 71, the filter paper 72, and the copper plate 74, the type and amount of the deposit in the installation environment can be grasped. Therefore, it is possible to select an appropriate insulating material according to the deposit, atmosphere, and the like. Further, by grasping the type of deposit, it can be recognized whether it is effective to remove the deposit by air purge.

  Since the environment measuring instrument 70 includes the temperature / humidity meter 73, it is possible to acquire data related to the presence or absence of the influence of deterioration acceleration due to the temperature and humidity of the above-described deposits and atmosphere. Therefore, it can be used for selection of a more appropriate insulating material or the like.

  According to the embodiment described above, it is possible to realize an induction heating apparatus that can prevent bus bar corrosion, sudden ground fault, dielectric breakdown, and the like from the invasion of scale, water, atmospheric gas, and the like.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalents thereof. Further, the above-described embodiments can be implemented in combination with each other.

  2 AC power supply, 3 external wiring, 4 heater, 5 core, 6 coil, 7 external connection terminal, 8a body frame, 9 housing, 10 internal wiring, 12 1st bus bar, 13 insulation layer, 14 2nd bus bar, 15 insulation Layer, 16 Insulating sheet, 17 Insulating plate, 18, 19 Clamp, 21, 22 Water-cooled pipe, 24, 25 Mounting member, 28 Insulating plate, 50 Rolled material, 60 Air purge mechanism, 61 Nozzle, 62 Piping, 70 Environmental measuring instrument 71 Deposit receiving box, 72 Filter paper, 73 Thermo-hygrometer, 74 Copper plate, 75 Installation plate

Claims (4)

An induction coil;
An internal wiring that electrically connects the induction coil and the AC power supply that supplies power to the induction coil;
With
The internal wiring is
A first bus bar including a portion extending in the first direction;
A second bus bar arranged in parallel to the first bus bar;
A first insulating plate provided between the first bus bar and the second bus bar;
A first portion and a second portion, extending in a second direction intersecting the first direction, the first bus bar, the second bus bar, and the first insulating plate, the first portion and the first portion; An insulating support member sandwiched between the two parts;
Including
The first bus bar and the second bus bar are provided with an insulating layer on the surface,
The length of the first portion and the second portion in the second direction is longer than the length of the first bus bar and the second bus bar in the second direction,
The area of the first insulating plate is larger than the area of the projection surface obtained by projecting the first portion and the second portion sandwiching the first insulating plate onto the surface of the first insulating plate,
The length of the said 1st insulating board in the said 2nd direction is an induction heating apparatus longer than the length of the said 1st part and the said 2nd part in the said 2nd direction.   The induction heating apparatus according to claim 1, wherein the second direction includes a direction parallel to an installation surface on which the induction heating apparatus is installed. An attachment member for attaching the support member to the conductive main body frame;
A second insulating plate provided between the mounting member and the main body frame;
The induction heating apparatus according to claim 1 or 2, further comprising:   The induction heating apparatus according to claim 1, further comprising an air purge unit that is provided above the support member and blows air onto the support member.

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