JPH0427114Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to coils used for high-frequency induction heating, and in particular, the invention relates to coils used for high-frequency induction heating. The present invention relates to an induction heating coil that is suitable as a high-frequency induction heating coil for use in heating applications.

[Conventional technology]

Many boiler steel pipes undergo stress relief annealing after welding. These methods currently rely on heating with propane, ethylene, or other flammable gases, resistance heating with nichrome wire, and high-frequency induction heating.

[Problem that the invention seeks to solve]

Among the conventional methods mentioned above, temperature control is not easy when heating with combustible gas. In addition, resistance wire heating using electric power allows for accurate temperature control, but
Indirect heating using resistance wire is inefficient.

On the other hand, heating by high-frequency induction is efficient because the temperature can be easily controlled and the heated object directly generates heat.

However, high-frequency generators used for high-frequency induction heating are generally too heavy and large in size and cannot be made portable. If the frequency used is selected and the output is limited to make it portable, even high-frequency induction heating, which has good heating efficiency, will still lack output.

An example of a conventional method will be explained with reference to FIG. FIG. 2 01 shows a heated steel pipe to be subjected to heat treatment, 02 shows an induction heating coil, and 03 shows a heat-resistant insulator separating the steel pipe 01 and the coil 02.

In general, many of the objects to be melted in steel pipes are long, so
It is difficult to insert the pre-wound coil 02 from the tube end.

Therefore, when attaching a heating induction coil to a steel pipe, it is necessary to wrap the coil cable around the steel pipe once at a time. In this way, since it is necessary to wind the cable around a long steel pipe, it is better to have fewer turns, but since the high frequency power supply has been made smaller, the current flowing through the coil is not small, so the number of coil turns is necessary due to the required ampere turns. There must be a large number of

In view of the above problems, the present invention aims to provide an induction heating coil that can obtain the same heating effect even if the number of turns is reduced compared to conventional induction coils.

[Means for solving problems]

Therefore, the induction heating coil according to the present invention consists of a linear induction heating coil with high electric resistance that can be wound spirally around the object to be heated, and a large number of insulators installed at regular intervals around the outer circumference of the induction heating coil. The gist is to become more and more.

[Effect]

That is, according to the present invention, this can be achieved by constructing the induction heating coil with a resistance wire and heating the object with a combination of the induction heating effect and the radiation heating effect of the resistance wire. Further, according to the present invention, since a large number of insulators are provided at regular intervals around the outer periphery of the induction heating coil, the induction heating coil can be directly wound around the object to be heated.

〔Example〕

FIG. 1 shows an embodiment of the present invention. 1 in the diagram
2 is a steel pipe to be heated, and 2 is an induction heating coil made of a resistance wire such as a nichrome wire, which is in contact with the steel pipe 1 through an insulator 3. 4 is a heat-resistant insulating material made of glass fiber, asbestos, or the like. Coil lead wires 5 and 6 are connected to a high frequency power source (not shown).

The lead wire 5 of the coil 2 configured in this way,
Power is supplied from a high frequency power source not shown in 6,
The steel pipe 1 to be heated is heated by induction heating by the coil 2, and the coil itself, which is made of resistance wire, generates heat due to the high frequency current flowing through the coil 2, producing the same effect as conventional resistance heating. Due to this effect, the steel pipe 1 is efficiently heated.

[Effect of idea]

According to the present invention, induction heating and radiation heating can be performed in combination, so even if the frequency and output are limited by a portable high-frequency generator and the number of turns of the coil is reduced, conventional high-frequency induction heating can be performed. It became possible to heat the same level as the conventional method.

Therefore, in the present invention, it is possible to perform conventional heating with a portable device using a coil with a small number of turns, so that it is possible to improve the efficiency of moving and heating operations. Furthermore, according to the present invention, since a large number of insulators are provided around the outer periphery of the induction heating coil, there is no need to provide heat-resistant insulators around the outer periphery of the object to be heated, unlike in the past. There are also effects that can be achieved directly by radiant heating.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an induction heating coil according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of induction heating according to a conventional method. 1... Steel pipe to be heated, 2... Induction heating coil.

Claims (1)

[Scope of utility model registration request] Induction heating is characterized by consisting of a linear induction heating coil with high electrical resistance that can be spirally wound around an object to be heated, and a large number of insulators installed at regular intervals around the outer circumference of the induction heating coil. coil.