JPS5856476B2 - induction heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating device suitable for heating the end portion of a material to be heated such as a metal rod or a metal plate, and particularly relates to an improvement in a heat equalizing device.

Conventionally, when inductively heating the end of a continuously conveyed metal rod or metal plate, etc., an elliptical solenoid-shaped solenoid that receives power from a power source 1 is used, as shown in Figures 1a and 1b. In some cases, the end of the material to be heated is inserted into the heating coil 2 to perform induction heating, and the heating coil 2 or the object to be heated 3 is sequentially moved and conveyed. There is one in which each material to be heated 3 is inductively heated one by one using a spiral heating coil 2 provided therein.

However, in the conventional device shown in FIG. 1, the heating length of the end of the heated material 3 is determined by the insertion length of the heated material 3 into the heating coil 2. If it is short, it is disadvantageous in terms of heating efficiency compared to the size of the heating coil 2.

In order to continuously heat the shredded material to be heated 3, it is necessary to provide a heating coil 2 and a device for moving the shredded or heated material 3 in the heating length direction, making the conveyance mechanism complicated and expensive. There are drawbacks to it.

Furthermore, if the shape of the material to be heated 3 becomes large, the heating temperature difference between the surface and the center of the material to be heated 3 becomes large, and a desired temperature distribution may not be obtained.

On the other hand, in the spiral-shaped heating coil 2 shown in FIG. However, it is necessary to prepare a plurality of heating coils 2 in consideration of heating efficiency and uniform heating depending on the shape and number of the heated materials 3.

For this reason, the number of feeder terminals equal to the number of heating coils is required, which not only complicates the feeder structure, but also makes preparation of a plurality of heating coils expensive and troublesome to maintain and inspect.

In addition, when a plurality of sheets are conveyed in succession, there is a drawback that if the tips are uneven, the heating length or temperature distribution will be different.

The present invention eliminates the above-mentioned drawbacks, makes it possible to simultaneously heat a plurality of materials to be heated, and improves heating efficiency and temperature distribution by combining it with a material conveying device at equal intervals. An object of the present invention is to provide an induction heating device suitable for partial heating.

An embodiment of the present invention will be described below with reference to the drawings.

3a and 3b show the heating section and conveyance section of the induction heating device according to the present invention, in which a rectangular or oval spiral heating coil 5 is connected to an AC power source 4 and receives power supply.
One or more movable magnetic concentrators 6 made of laminated iron plates are provided in the central space 5a at appropriate intervals in correspondence with the materials to be heated, which will be described later.

The transport section is configured to transport the material to be heated 8 along the heating coil 6 using a walking beam transport device 7 connected to the heating coil 5 by a connecting rod 10 and sequentially heat the ends thereof.

In the induction heating device having such a configuration, the heating coil 5
The alternating magnetic flux generated by the alternating current flowing from the power supply 4 generates an eddy current at the end of the heated material 8 facing the heating coil 5, and generates Joule heat due to the eddy current and the resistance of the heated material 8 itself. Heating takes place.

However, this alternating magnetic flux does not generate a uniform eddy current across the opposing heated material 8, but the magnetic flux concentrates on protrusions such as edges, making them more likely to be heated, and as a result, the center When the temperature at the edge of the surface becomes high, a temperature difference occurs and uniform heating cannot be measured.

Therefore, in the present invention, the heating of the central part is promoted by concentrating the magnetic flux near the center of the opposing heated material 8 through the magnetic concentrator 6 provided in the central space 5a of the heating coil 5, and the surface edge The temperature difference between the parts and the center can be reduced.

In this case, the shape and size of the magnetic concentrator 6 are determined based on the name and size of the heated material 8, and the tension between the magnetic concentrator 6 and the heated material 5 is determined based on the optimum heating conditions, thereby improving the heating efficiency. temperature distribution and temperature distribution.

The present invention can be combined with a conveying device that maintains a constant space between the housing and the material to be heated 8, such as a commonly used walking beam type conveying device.

This makes it possible to move the heating coil 5 and the heated material 8 in order to improve temperature distribution and heating efficiency when the shape and size of the heated material 6 changes, as in the conventional case.
There is no need to replace the magnetic concentrator 6, the temperature distribution and heating efficiency can be improved by moving or replacing only the magnetic concentrator 6, and even if the tip of the heated material 8 is uneven during transportation,
If the magnetic concentrator 6 can be set so that the position of the tip and the tension between the magnetic concentrator 6 and the magnetic concentrator 6 are constant, a constant temperature distribution can always be obtained.

Further, by connecting the heating coil 5 and the walking beam conveying device and synchronizing the orbits, the relative positions of the heated material 8 and the heating coil 5 do not change even while the heated material is being transported, so that heating can be performed while the material is being transported.

Therefore, the ratio of heating time to one cycle of the walking beam conveyance device becomes large, so that efficient heating can be performed without requiring a high load factor.

Next, another embodiment of the present invention will be described.

In the embodiment shown in FIG. 3, the magnetic concentrator 6 and the material to be heated 8 correspond to each other independently, but as shown in FIGS. 6 may be integrated.

Alternatively, as shown in FIG. 5, a refractory material 9 of an arbitrary thickness may be attached to the tips of a plurality of magnetic concentrators 6 and brought into close contact with the facing surface of the material to be heated 8.

In each of the above embodiments, heating of the end of a metal round bar was explained, but the heating target material can also be applied to a polygonal or plate-shaped cross section.

As described above, according to the present invention, a movable magnetic concentrator is provided in the central space of a spiral heating coil in correspondence with the material to be heated, and the device conveys the material to be heated at regular intervals, for example. By combining it with a walking beam conveying device or the like, it is possible to obtain an induction heating device with good heating efficiency, uniform temperature, easy maintenance and inspection, and high load factor without increasing the number of coil types.

[Brief explanation of the drawing]

1 and 2 are diagrams showing a conventional induction heating device, respectively, in which a is a plan view, b is a city view, and FIG. 3 is a diagram showing an embodiment of the present invention, in which a is a plan view and b is a front view. 4 are views showing another embodiment of the present invention, in which a is a plan view, b is a front view, and FIG. 5 is a plan view similarly showing another embodiment. 4... Power supply, 5... Heating coil, 5a... Space of heating coil, 6... Magnetic inductor, 7... Conveyance device, 8... Material to be heated.

Claims (1)

[Claims] 1. A power source, a spiral heating coil that is rectangular or oval and has a space in the center and is connected to the power source and heats the material to be heated, and the space in the heating coil. An induction heating device comprising a plurality of movable magnetic concentrators provided corresponding to the ends of a material to be heated, and a conveyance device that transports the material to be heated while heating the material at an arbitrary interval.