JPS6323910Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating coil, and more particularly to an induction heating coil that is most suitable for drying an object coated with a liquid containing water or other substances.

In rolling mills and the like, as part of the strip surface treatment process, a coating/drying process is sometimes provided in which an aqueous solution containing water or other substances is applied to the surface, followed by drying and baking.

In the heating method of such a drying oven, induction heating is used because of the advantages listed below.

(a) Controllability of strip temperature (stability, rapid response,
The quality of the products is stable because of the high accuracy (accuracy).

(b) High heating efficiency.

(c) Since the energy source is electricity, there are no environmental problems.

FIG. 1 shows the arrangement of induction coils provided in the drying oven to take advantage of these advantages, the temperature rise curve of the strip corresponding to the coil group, and the position of the evaporation zone.

As shown in Fig. 1, a plurality of induction heating coils (the figure shows an example of six) are provided, and the strip is sequentially conveyed through these coils.
The temperature of the strip is gradually increased. In such an induction heating coil, only the strip, which is the object to be heated, is heated, and the ambient temperature does not rise.

As shown in Fig. 2, the induction heating coil is constructed by attaching flanges 2 made of asbestos plates or the like to both ends of a coil in which a coil conductor 1, which is a copper tube covered with insulating tape, is tightly wound in a cylindrical shape the required number of times. Ru.
Furthermore, the induction heating coil is as shown in Figure 3.
From the viewpoint of preventing heat radiation, the inner surface has a sealed structure in which the entire surface is covered with a heat insulating board 3 (for example, an asbestos cement board) as shown in FIG.

Due to this structure, when a strip coated with a liquid material is passed through a drying oven, the water solute on the surface of the strip evaporates in the evaporation zone, and the water vapor generated in the evaporation zone condenses on the inner surface of the coil. Then, the water becomes a droplet 10 and drips onto the surface of the strip 4. This causes dirt and rust to occur on the surface of the strip, and in the case of strips whose surfaces have been coated, defects in the coating may occur, resulting in serious quality problems. Furthermore, the drying furnace has a closed structure, which obstructs the diffusion of water vapor itself, which causes a reduction in thermal efficiency.

As a solution to such problems, Figure 4 a and b
As shown in Fig. 4, there is a method in which the heat insulating material is removed and a gap 5 is provided between the conductors to facilitate the diffusion of water vapor and prevent problems caused by falling water droplets (see Fig. 4 a and b). 6 is a support stand on which the coil conductor 1 is placed, and 7 is a support section steel that connects each coil conductor). In this case, the cross section of the coil conductor 1 is as shown in FIG. 5, with cooling water 32 flowing inside the copper tube 31 forming the coil conductor 1, and an insulating tape 33 being wrapped around the outer periphery of the copper tube 31. There is.

Even in this case, if the amount of water vapor generated on the outer peripheral surface of the insulating tape 33 is small, the configurations shown in FIGS. 4 and 5 are effective, but if the amount of water vapor generated is large, the water vapor is There is a disadvantage that dew condenses on the surface and drips onto the strip surface.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks, and to provide an induction heating coil that can prevent water dripping due to condensation of water vapor generated on the coil conductor.

In this invention, the current flowing through the coil conductor is concentrated on the inner circumferential surface of the conductor (at a certain depth determined by the frequency) on the surface facing the strip (current corresponding to approximately 90% of the power flows), and Focusing on the fact that the temperature of the side surface and the temperature of the outside surroundings are almost the same as the temperature of the cooling water flowing inside the conductor, and that water vapor from the strip surface easily condenses and condenses, we developed a U-shaped groove that blocks dripping. A conductor is provided between the conductor and the strip.

FIG. 6 is a sectional view showing an embodiment of the present invention.
In FIG. 6, parts that are the same as those shown in FIG. 5 are given the same reference numerals.

As shown in FIG. 6, a U-shaped groove member 12 is attached to the lower surface of the coil conductor 1 by inserting a heat insulating material 11 therein.
As the heat insulating material 11, a material that does not transmit heat to the U-shaped groove body 12, such as asbestos, is used. Also,
Since the U-shaped groove body 12 is installed at a distance from the coil conductor 1, there is no need to use heat-resistant material.
A product made of resin can be used. In this case, metal cannot be used because it absorbs high frequency power. The shape of this U-shaped groove body 12 is as follows:
Any shape may be used as long as it can catch water droplets generated on the surface of the coil conductor. As a result of the U-shaped groove 12 being coupled to the coil conductor 1 via the heat insulating material 11, the degree of dew condensation on the surface of the U-shaped groove 12 is extremely small compared to the dew condensation that occurs on the surface of the coil conductor. As well as dripping troubles are significantly reduced.

As described above, according to the present invention, by providing the water droplet receiving portion, it is possible to prevent water droplets from dripping onto the surface of the material to be dried.

[Brief explanation of the drawing]

Fig. 1 is a heating characteristic diagram of the drying oven, Fig. 2 is a front view of the induction heating coil shown in Fig. 1, Fig. 3 is a side view of the coil, and Fig. 4a is another conventional induction heating coil. Figure 4b is a side view of the coil for
5 is a cross-sectional view of the coil conductor of the induction heating coil shown in FIG. 4, and FIG. 6 is a cross-sectional view showing an embodiment of the coil conductor of the induction heating coil according to the present invention. 1...Coil conductor, 11...Insulating material, 12...
U-shaped groove body, 31...Copper pipe, 32...Cooling water, 3
3...Insulating tape.

Claims (1)

[Scope of utility model registration request] In an induction heating coil for inductively heating an object to be dried by supplying high frequency power to a coil conductor through which a cooling fluid is passed through, a U formed of an insulator is provided at the lower part of the coil conductor via a heat insulating material. An induction heating coil characterized by being provided with a water droplet receiving portion made of a groove-shaped body.