JP4097859B2 - Induction heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a structure for preventing a heating coil of an inductor for induction heating a material to be continuously conveyed from radiation heat of the material to be heated.
[0002]
[Prior art]
In general, in a hot rolling line for steel, a plate-like material to be heated (slab) heated in advance in a heating furnace to a high temperature is continuously processed into a thin plate through a rolling mill. When rolling a thin plate in such a hot rolling line for steel, the temperature of the plate-shaped heated material heated in the heating furnace decreases while traveling on the line, so the overall temperature of the heated material is adjusted with a slab heater. Once the temperature is increased and the edge side is cooled during running, the edge is heated by an edge heater that heats the edge locally, and the whole is brought to a substantially uniform temperature, and then rolled by a rolling mill to form a thin plate. Yes.
[0003]
As this edge heater, an induction heating device is used in which a heating coil is wound around each opening leg portion of a C-shaped iron core, and a material to be heated is passed between the heating coils to perform induction heating. As shown in FIG. 3, the inductor of this induction heating apparatus is formed by winding a water-cooled copper tube around the leg outer periphery of the C-shaped iron core 1 to form a heating coil 2, and the heating coil 2 facing the material to be heated 3. A mounting plate 4 made of an electrical insulating plate is provided on the surface side, a water-cooled pipe 5 is supported here, and the water-cooled pipe 5 is embedded in a refractory insulating material 6 to form a heat insulating plate 8, and a heated material The heating coil 2 is protected from the radiant heat 3.
[0004]
The side surface of the heating coil 2 is surrounded by a side cover 9. The side cover 9 is configured by combining a magnetic shield plate 10 and a heat-resistant plate 11. The magnetic shield plate 10 has a structure in which a water-cooled pipe 13 is joined to the inner surface of a copper plate 12, and the heat-resistant plate 11 is formed of a stainless steel plate 14. The end of the stainless steel plate 14 on the heated material 3 side is bent into an L shape, and a plurality of slits 15 are formed therein as shown in FIG. 4A, and eddy currents are generated by magnetic flux passing through the slits 15. This prevents the end from being induction heated.
[0005]
Since the heating coil 2 is disposed in the vicinity of the heated material 3 that is induction-heated to about 1200 ° C., the magnetic shield plate 10 and the heat-resistant plate 11 constituting the side cover 9 generate high-temperature radiant heat over a long period of time. receive. When the thermal expansion and contraction are repeated over a long period of time as described above, the heat-resistant plate 11 is gradually deformed so as to wave, and the gap 16 between the heat insulating plate 8 and the heat-resistant plate 11 as shown in FIG. Will open. Since the slit 15 is formed when the gap 16 with the heat insulating plate 8 is thus opened, water and oxide scale enter the inside from this, and the heating coil 2 is directly exposed to radiant heat. . As a result, the insulation coating of the heating coil 2 may burn out, or a water leakage accident of the cooling hose may occur, leading to a short circuit accident.
[0006]
[Problems to be solved by the invention]
The present invention eliminates the above disadvantages, eliminates the gap between the side cover and the refractory insulating material to prevent water and oxide scale from entering, prevents the influence of radiant heat from the heated material, An induction heating apparatus having improved durability and reduced replacement frequency is provided.
[0007]
[Means for Solving the Problems]
The induction heating device according to claim 1 of the present invention is the induction heating device in which the heating coil is wound around each of the opening legs of the C-shaped iron core, and the material to be heated is passed through the heating coil in the meantime. A side cover provided with a heat-resistant plate on the outside via a magnetic shield plate is attached to the surrounding side surface, and a mounting plate having a concave cross section formed of an electrical insulating material on the heated material side of the heating coil, the upper corner portion of which is Covered so as to be located at the end of the heat-resistant plate, and supported by piping a water-cooled pipe along the cross-sectional shape outside the mounting plate, this water-cooled pipe was embedded in a refractory insulating material to form a heat insulating plate It is characterized by this.
[0008]
The induction heating apparatus according to claim 2 is characterized in that a copper plate is used as the magnetic shield plate, a stainless plate is used as the heat-resistant plate, and a resin laminated plate is used as the mounting plate. Furthermore, the induction heating device according to claim 3 is characterized in that a heat insulating plate formed by providing a refractory insulating material on the surface of a mounting plate having a concave cross section with a water-cooled pipe mounted thereon is divided. .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. In the inductor of this induction heating apparatus, a water-cooled copper tube is wound around the outer periphery of the leg of the C-shaped iron core 1 to form a heating coil 2, and a mounting plate 4 is provided on the surface side of the heating coil 2 facing the material to be heated 3. Is provided. The mounting plate 4 is made of an electrical insulating material such as an epoxy resin laminate and has a concave cross section. On the outside of the mounting plate 4 facing the material to be heated 3, a water-cooled pipe 5 meandering along the concave shape of the cross section of the mounting plate 4 is supported. Further, a fireproof insulating material 6 such as castable cement is provided on the surface of the mounting plate 4, and a water cooling pipe 5 supported by the mounting plate 4 is embedded in the fireproof insulating material 6 to form a heat insulating plate 8.
[0010]
Further, the side surface side of the heating coil 2 is surrounded by a side surface cover 9 in which a magnetic shield plate 10 and a heat-resistant plate 11 are combined. The magnetic shield plate 10 has a structure in which a water-cooled pipe 13 is joined to the inner surface of a copper plate 12, the heat-resistant plate 11 is formed of a stainless steel plate 14, and the heated material 3 side of the magnetic shield plate 10 is the heat-resistant plate 11. It is formed longer. The mounting plate 4 provided with the heat insulating plate 8 having a concave cross section on the surface is prepared separately in advance, and this is placed on the heated material 3 side of the heating coil 2, and the upper corner portion of the mounting plate 4 is the magnetic shield plate 10. It is attached so that it covers the outer side of the end and is in close contact with the end of the heat-resistant plate 11.
[0011]
The inductor of the induction heating apparatus having the above configuration is disposed in the vicinity of the material to be heated 3 that is conveyed along the line, and receives radiant heat from the material to be heated 3 that is induction-heated to about 1200 ° C. In this case, since the heated material 3 side of the heating coil 2 is covered with the heat insulating plate 8 in which the water-cooled pipe 5 is embedded, heat can be shut off. In addition, the influence of heat can be prevented on the corner side through which the magnetic flux concentrates and receives the radiant heat from the material 3 to be heated, since the water-cooled heat insulating plate 8 is formed in a concave shape. Further, the heat-resistant plate 11 is in close contact with the peripheral edge of the mounting plate 4 and is located at the upper corner of the heat insulating plate 8, and the heating coil 2 side is shielded to the end by the magnetic shield plate 10, so that the magnetic flux passes therethrough. It is possible to reduce the influence of induction heating by radiant heat and radiation heat from the material to be heated 3.
[0012]
For this reason, compared with the conventional structure in which the corner portion of the inductor is covered with the heat-resistant plate 11 provided with the slits 15, the corner portion having the greatest thermal influence is constituted by the heat insulating plate 8 and thus has a long period of time. Even if it is used, no gap is formed, and durability can be improved.
[0013]
FIG. 2 shows another embodiment of the present invention, in which the mounting plates 4 and 4 are divided into two parts, the water-cooled pipes 5 and 5 meandering on the surface are supported, and the surfaces of the mounting plates 4 and 4 are castable. Heat insulating plates 8 and 8 having a two-part structure are provided by providing refractory insulating materials 6 and 6 such as cement. Since the heat insulating plates 8 and 8 having a two-part structure are separately formed and attached to the C-shaped iron core 1, manufacturing and replacement work are easy.
[0014]
In the above description, the case where the heat insulating plate 8 has a two-divided structure is shown.
[0015]
【The invention's effect】
As described above, according to the induction heating device of the first aspect of the present invention, since the corner portion having the greatest heat influence is constituted by the water-cooled heat insulating plate, a gap is generated even when used for a long period of time. In addition to preventing intrusion of water and oxide scale, the influence of radiant heat from the heated material can be prevented, and the durability of the side cover can be improved to reduce the replacement frequency.
[0016]
The induction heating device according to claim 2 uses a copper plate as the magnetic shield plate, so that it has an excellent magnetic shield effect and has good thermal conductivity and can be cooled by a water-cooled pipe to protect the heating coil. Further, since a stainless steel plate is used as the heat-resistant plate, it is difficult to be deformed against high-temperature radiant heat. Further, by using a resin laminate as the mounting plate, it is excellent in electrical insulation, and the support strength of the water-cooled pipe and the fireproof insulating material can be improved. Furthermore, the induction heating apparatus according to claim 3 is easy to manufacture and replace because the heat insulating plate has a split structure.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an induction heating device according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a heat insulating plate having a divided structure according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a conventional induction heating apparatus.
4A is a perspective view showing a corner portion of the induction heating apparatus of FIG. 3, and FIG. 4B is a perspective view showing a corner portion where a gap is generated due to thermal deformation.
[Explanation of symbols]
1 C-shaped iron core 2 Heating coil 3 Heated material 4 Mounting plate 5 Water-cooled pipe 6 Refractory insulating material 8 Thermal insulating plate 9 Side cover 10 Magnetic shield plate 11 Heat-resistant plate 12 Copper plate 13 Water-cooled pipe 14 Stainless steel plate 15 Slit 16 Gap

Claims (3)

In an induction heating apparatus in which a heating coil is wound around each open leg portion of a C-shaped iron core and a material to be heated is passed through the heating coil, heat resistance is applied to the side surface surrounding the heating coil via a magnetic shield plate. A side cover provided with a plate is attached, and a mounting plate having a concave cross section formed of an electrical insulating material is placed on the heated material side of the heating coil so that the upper corner portion is located at the end of the heat-resistant plate. An induction heating device characterized in that a water-cooled pipe is piped and supported on the outside of the mounting plate along the cross-sectional shape, and the water-cooled pipe is embedded in a refractory insulating material to form a heat insulating plate. The induction heating apparatus according to claim 1, wherein a copper plate is used as the magnetic shield plate, a stainless plate is used as the heat-resistant plate, and a resin laminated plate is used as the mounting plate. 2. The induction heating apparatus according to claim 1, wherein a heat insulating plate formed by providing a fireproof insulating material on a surface of a mounting plate having a concave cross section to which a water cooling pipe is attached has a divided structure.

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