JP3129917B2 - Inductor for induction heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved surface cooling structure of an inductor for locally inductively heating the end of a material to be heated in a steel rolling line.

[0002]

2. Description of the Related Art Generally, when a material to be heated such as a slab, a hot bar or a strip is continuously run in a steel rolling line and rolled by a rolling mill, a temperature drop at an end portion of the material to be heated is large. On the upstream side of the rolling mill, the temperature-lowered end portion is locally heated by the inductor of the induction heating device. Conventionally, the inductor of such an induction heating device is configured, for example, as shown in FIG.

In the inductor of this induction heating apparatus, a heating coil 3 is wound around a concave groove 2 of a grooved iron core 1 and fixed in a heat insulating material 4. The structure is such that the insulating coating of the heating coil 3 is protected against radiant heat from the material 5 to be heated by coating with the heat-resistant plate 7. The heat-resistant plate 7 is formed by solidifying the fiber with a binder, and is for preventing the oxide scale peeled from the material 5 to be heated from being sucked by the large electromagnetic force generated in the heating coil 3 and penetrating the heat-resistant plate 7. , Especially to increase hardness. In addition, the radiant heat is insulated by a heat insulating plate 6 having a high porosity inside the heat resistant plate 7 to protect the heating coil 3.

However, since the heat-resistant plate 7 is heated to a high temperature by radiant heat from the material 5 heated to about 1200 ° C., its strength is reduced due to high-temperature deterioration of the binder, and a large thermal stress is applied to the surface. The cracks gradually occur inside and the damage is severe. Furthermore, since the inner heat insulating plate 6 has a high porosity and excellent heat insulating properties, but does not have a high mechanical strength, when a crack occurs in the heat resistant plate 7, a conductive oxide scale penetrating from the crack is formed. There is a possibility that a short circuit may occur by penetrating the heat insulating plate 6 and reaching the heating coil 3 to damage the insulating coating.

[0005] In addition, the heating coil 3 may be directly exposed to high-temperature radiant heat due to damage to the heat-resistant plate 7 and the heat-insulating plate 6, and the insulating coating may be burned. For this reason, in the conventional structure, the heat-resistant plate 7 on the surface and the entire heat-insulating plate 6 on the inside must be exchanged about once every two weeks, and there is a problem that the operation rate of the induction heating device is reduced.

[0006]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned drawbacks, prolongs the life of the heat-resistant plate, prevents insulation breakdown and short-circuit of the heating coil for a long time, and enables stable operation. Another object of the present invention is to provide an inductor of an induction heating device that can prevent a decrease in heating efficiency due to induction heating of a cooling pipe and can repair only a damaged portion of a heat-resistant plate.

[0007]

According to a first aspect of the present invention, there is provided an inductor for an induction heating apparatus, wherein a heating coil is wound around a groove of a grooved iron core, and a heat-resistant plate is formed on a surface of the grooved iron core facing a material to be heated. In the inductor of the induction heating device having attached thereto, the heat-resistant plate is formed by combining a plurality of plate-shaped blocks formed of castable cement molded products or fired products into a flat plate, and a non-magnetic material is formed inside the plate-shaped blocks. A cooling pipe made of a material is embedded, and an insulating support plate is provided between the heat-resistant plate and the grooved iron core. The insulating support plate supports the cooling pipe embedded in the plate-shaped block. It is characterized by the following.

According to a second aspect of the present invention, the heat-resistant plate is formed by combining the ends of the plate-like blocks, which are adjacent to each other, into a flat structure.

[0009]

The inductor of the induction heating apparatus according to the present invention is disposed close to the upper and lower surfaces of the running material to be heated, and a high frequency current is applied to the heating coil to continuously connect the end of the material to be heated. Induction heating. On the other hand, the heat-resistant plate attached to the surface of the inductor facing the material to be heated has a cooling pipe embedded inside, and cooling water is passed through this cooling pipe to cool it from the inside. Even when heated by radiant heat from the material, the rise in temperature is kept low, and deterioration and cracking of the heat-resistant plate can be prevented for a long period of time. In addition, the connection strength of the heat-resistant plate can be improved and the life can be greatly extended. Further, since the heat-resistant plate is formed by combining a plurality of plate-like blocks in which cooling pipes are embedded in a plate shape, if a part is damaged, only the damaged plate-like block can be replaced.

The magnetic flux generated from the heating coil interlinks with the cooling pipe. However, the cooling pipe is formed of a non-magnetic material, and is supported by an insulating support plate, is electrically insulated, and does not form a closed loop. Is not induction-heated, and a decrease in heating efficiency can be prevented. Furthermore, in the invention according to claim 2, since a plurality of plate-like blocks are fitted to each other to combine the heat-resistant plates in a flat plate shape, the connection strength of the heat-resistant plates is increased, and radiant heat from the fitting portion is prevented from entering. can do.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. A heating coil 3 formed of a water-cooled copper tube is wound around the concave groove 2 of the grooved iron core 1 and fixed in the heat insulating material 4. The plate 9 is attached, and the periphery thereof is supported by a support frame 10. The heat-resistant plate 9 is formed by combining three plate-like blocks 11 formed of castable cement molded products or fired products into a flat plate shape.

As shown in FIG. 2, each plate-like block 11 has a cooling pipe 12 made of a non-magnetic material embedded in a U-shape. One end of the cooling pipe 12 is connected to a header pipe 13 on the water supply side, and the other end is connected to the header pipe 13. It is connected to the header pipe 14 on the drain side so that cooling water flows through the inside. Bolts 15 are attached to the upper part of the cooling pipe 12 at predetermined intervals.
3 penetrates the insulating support plate 8 as shown in FIG.
At the insulating support plate 8. Plate-like block 1
1 is formed with a chevron-shaped projection 17 on the end face of one adjacent plate-shaped block 11 and a chevron-shaped recess 18 on the other end face, into which the protruding part 17 is fitted. The mortar 19 is packed and connected together to form a flat plate.

The inductor of the induction heating device having the above structure is
The heating material 5 is continuously heated and arranged by supplying a high-frequency current to the heating coil 3 at intervals of a few mm from the heating material 5 on the upper and lower surfaces of the traveling material 5 or on both left and right sides of the upper and lower surfaces. The end side of the material 5 is induction-heated. In this case, cooling water is passed from the header pipe 13 on the water supply side to the cooling pipe 12 embedded inside the heat-resistant plate 9 attached to the surface of the inductor facing the material 5 to be heated, and the cooling water is drained from the header pipe 14 on the drain side. I do. For this reason, the heat-resistant plate 9 is cooled from the inside,
Even when heated by radiant heat from the material 5 to be heated, the temperature rise can be kept low. Further, since the mortar 19 is filled between the fitting portions of the plate-shaped blocks 11 constituting the heat-resistant plate 9 to close the gap, it is possible to prevent radiant heat from entering there.

Accordingly, there is no thermal deterioration or cracking of the heat-resistant plate 9 and the hardness and strength are maintained, and the penetration of the oxide scale and the insulation deterioration of the heating coil 3 can be prevented. As a result, conventionally,
What has been replaced every week can be used for more than 6 months, the replacement interval can be greatly extended, and the operation rate of the induction heating device can be greatly improved.

The magnetic flux generated from the heating coil 3 is linked with the cooling pipe 12. The cooling pipe 12 is formed of a non-magnetic material, and is supported by the insulating support plate 8 to be electrically insulated to form a closed loop. Since it is not performed, the cooling pipe 12 is not heated, and the heating efficiency is not reduced. Further, since the heat-resistant plate 9 is formed by fitting a plurality of plate-like blocks 11 into a flat plate shape, the heat-resistant plate 9 is compact and easy to mold. It is possible to prevent radiant heat from entering from the part. Further, in the case where the heated material 5 collides with the heat-resistant plate 9 and some of the plate-like blocks 11 are damaged, since only the cooling pipes 12 are buried, only the damaged plate-like blocks 11 are replaced. The repair work can be performed easily.

FIG. 4 shows another embodiment of the present invention.
A protruding portion 20 is formed on one end surface of the plate-shaped block 11 with the adjacent plate-shaped block 11, and a concave portion 21 is formed on the other end surface of the protruded portion 20. The mortar 19 is packed in the meantime and combined to form the flat heat-resistant plate 9. FIG. 5 shows a flat heat-resistant plate 9 in which inclined surfaces 22, 22 are formed on both end surfaces of a plate-like block 11, adjacent inclined surfaces 22, 22 are overlapped, and a mortar 19 is filled between the inclined surfaces.

In FIG. 6, a cooling pipe 12 made of one non-magnetic material is embedded inside a plate-shaped block 11, and a convex curved surface 23 is fitted on one end surface of the plate-shaped block 11 and fitted on the other end surface. A concave curved surface 24 is formed, and the convex curved surface 23 and the concave curved surface 24 are fitted to each other, and a mortar 19 is packed between them to form the flat heat-resistant plate 9. In this case, the header pipes are arranged on both sides of the cooling pipe 12.

[0018]

As described above, according to the present invention, a heat-resistant plate is formed by combining a plurality of plate-like blocks, and a cooling pipe made of a non-magnetic material is piped in the plate-like block to form an inner portion. Since it is cooled from the start, the heating by the radiant heat from the material to be heated is lowered, the life of the heat-resistant plate is greatly extended, the insulation breakdown and short circuit of the heating coil are prevented for a long time, and stable operation is performed be able to.

Further, since the heat-resistant plate is formed by combining a plurality of plate-like blocks each having a cooling pipe embedded therein, molding is easy, and when a part is damaged, only the damaged plate-like block is replaced. Repair work is also easy. Further, since the cooling pipe buried in the plate-shaped block is supported by the insulating support plate, no current turn is formed, so that the cooling pipe is not heated, and a decrease in heating efficiency can be prevented.

Further, in the inductor according to the second aspect of the present invention, the adjacent ends of the plate-like block are fitted to each other to form a single heat-resistant plate by combining them into a flat plate shape. It is possible to prevent radiation heat from entering from the fitting portion.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an inductor of an induction heating device according to an embodiment of the present invention.

FIG. 2 is a horizontal sectional view showing a heat-resistant plate of the inductor of FIG.

FIG. 3 is an enlarged sectional view showing main parts of a heat-resistant plate and an insulating support plate of FIG. 1;

FIG. 4 is a cross-sectional view illustrating a heat-resistant plate according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a heat-resistant plate according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a heat-resistant plate according to another embodiment of the present invention.

FIG. 7 is a sectional view showing a conventional inductor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 grooved iron core 2 concave groove 3 heating coil 4 heat insulating material 5 material to be heated 6 heat insulating plate 7 heat resistant plate 8 insulating support plate 9 heat resistant plate 11 plate-shaped block 12 cooling pipe 17 mountain-shaped protrusion 18 mountain-shaped recess 19 mortar

Continued on the front page (56) References Japanese Utility Model Hei 5-25690 (JP, U) Japanese Utility Model Hei 6-73896 (JP, U) Japanese Utility Model Hei 6-73897 (JP, U) (58) Fields surveyed (Int) .Cl. ⁷ , DB name) H05B 6/10 H05B 6/42 E04B 1/76

Claims (2)

(57) [Claims] 1. A heating coil is wound around a groove of a grooved iron core,
In an inductor of an induction heating device in which a heat-resistant plate is attached to a surface of a grooved iron core facing a material to be heated, the heat-resistant plate is formed by casting a plurality of plate-like blocks formed of castable cement molded products or fired products. A cooling pipe made of a non-magnetic material is embedded inside the plate-shaped block, and an insulating support plate is provided between the heat-resistant plate and the grooved iron core. An inductor for an induction heating device, wherein a cooling pipe buried in the plate-like block is supported. 2. The inductor for an induction heating apparatus according to claim 1, wherein the adjacent ends of the plate-like blocks are fitted to each other in a fitting structure to form a heat-resistant plate.