JPS635200Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a protection device for an induction heating coil that heats a good electrical conductor such as metal.

[Conventional technology]

In the hot rolling process, in order to prevent the occurrence of surface defects such as edge cracks and shape defects such as ear waves due to temperature drop at the edges of the rolled material, the edges of the rolled material are removed at the entrance of the rolling mill. Conventionally, a heating method using an induction heating device has been used. The induction heating coil used in the apparatus is, for example, a coil such as that described in Japanese Patent Application Laid-Open No. 57-21088, in which a conducting wire is wound around an iron core made of laminated electromagnetic steel plates. The induction heating coil cools the iron core and the windings in order to prevent functional deterioration of the iron core and deterioration of the insulation of the windings due to temperature rise. Further, at least the side of the induction heating coil facing the material to be heated is covered with a heat insulating refractory.

[Problem that the invention seeks to solve]

By the way, the distance between the induction heating coil and the material to be heated is set as small as possible in order to increase heating efficiency, but as a result, the material to be heated may bend, warp, vibrate, meander, etc. during heating. The heat insulating refractory of the induction heating coil may come into contact with the heat insulating refractory and be damaged, and the temperature of the induction heating coil may rise, resulting in a decrease in function and insulation. Conventionally, damage to this insulating refractory was detected by detecting the temperature of the cooling water that cools the windings and iron core of the induction heating coil, and then detecting damage by detecting the temperature rise of the cooling water. . However, with these conventional methods, it is difficult to set the temperature level to determine the presence or absence of damage, it is difficult to obtain a stable temperature detection signal, the sensitivity is poor, and the response is slow, making it difficult to detect damage. However, there was a problem in that it was difficult to effectively implement measures to prevent burnout of the induction heating coil.

The present invention aims to solve the problems of the conventional methods as described above and to provide a protection device for an induction heating coil that can detect damage to an insulating refractory at an early stage.

[Means for solving problems]

The device of the present invention for this purpose covers at least the side facing the material to be heated of an induction heating coil placed close to the material to be heated with a heat insulating refractory material, and embeds an optical fiber in the heat insulating refractory material. A protection device for an induction heating coil is characterized in that one end of the coil is connected to a light emitting section and the other end is connected to a light receiving section.

The present invention will be explained below based on the illustrated embodiments. FIG. 1 is a front sectional view showing the structure of a protection device according to an embodiment of the present invention, and FIG. 2 is a view taken along the line A--A in FIG. In the figure, reference numeral 1 denotes an iron core made of laminated electromagnetic steel plates, and has a structure in which a plurality of water cooling jackets for cooling are sandwiched between the cores. 2 is a winding, which has a structure in which a hollow conducting wire is wound to pass cooling water. 3 is a heat insulating refractory. 4 is a heat insulating refractory 3 which is a buried optical fiber, one end of the optical fiber 4 is connected to a light emitting section 5, and the other end is connected to a light receiving section 6.
It is connected to the.

The optical fibers 4 within the heat insulating refractory 3 may be placed directly, but it is more preferable to arrange them in a zigzag pattern as shown in FIG. 2, since damage to the heat insulating refractory can be detected over a wide area. Furthermore, if a plurality of sets of a light emitting part, an optical fiber, and a light receiving part are provided, the position of the damaged part can also be detected. There are methods of embedding the optical fiber in the heat insulating refractory 3, a method of embedding it at the same time as applying refractory mortar, a method of providing a small diameter pipe or groove for passing the optical fiber in the refractory brick, and inserting it therein.

In the example device shown in FIG. 1, if there is no damage to the heat insulating refractory 3 or the damage is slight, the optical fiber will not be broken and the light from the light emitting part 5 will be received by the light receiving part 6. When there is a light reception signal, it is determined that there is no damage to the fireproof insulation part.

When the material to be heated comes into contact with the heat-insulating refractory and the heat-insulating refractory is stripped off, or when the heat-insulating refractory is missing for some reason, the optical fiber 4 buried in the heat-insulating refractory is cut. Light emitting part 5
Since the light from the refractory is cut off, the light reception signal of the light receiving section 6 disappears, and damage to the heat insulating refractory can thereby be detected. That is, a signal detection circuit (not shown) detects that the light reception signal from the light receiving section 6 is no longer present, and based on this detection signal, the induction heating coil can be quickly retracted or the power supply can be shut off.

[Effect of idea]

Since the induction heating coil protection device of the present invention has the above-described configuration, it has a practically excellent effect of being able to reliably detect damage to the heat insulating refractory covering the induction heating coil.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing the structure of a protection device according to an embodiment of the present invention, and FIG. 2 is a view taken along the line A--A in FIG. 1. 1: iron core, 2: winding, 3: heat insulating refractory, 4: optical fiber, 5: light emitting section, 6: light receiving section.

Claims (1)

[Scope of utility model registration request] At least the side facing the heated material of an induction heating coil placed close to the heated material is covered with a heat insulating refractory, an optical fiber is buried within the heat insulating refractory, and one end of the optical fiber is used as a light emitting part. 1. A protection device for an induction heating coil, characterized in that the coil is connected to a light receiving section, and the other end is connected to a light receiving section.