What Is High Frequency Heating Equipment?
High-Frequency Heating Equipment is a type of heat supply system that utilizes the principle of induction heating and uses a high-frequency oscillator as its energy source.
Generally, it is a direct heating system for metal, but it can also heat other materials through that metal.
Uses of High-Frequency Heating Equipment
High-Frequency Heating Equipment has been introduced in metal metallurgy and other situations where heat treatment is required. Compared to conventional heating systems such as gas furnaces and electric furnaces, High-Frequency Heating Equipment can be made smaller, making it suitable for situations where space-saving is required.
In addition, the heating method of applying an electric current to the metal itself produces almost no by-products such as scale, making the furnace a perfect match for use in clean room environments such as semiconductor manufacturing facilities.
High-Frequency Heating Equipment can be used to uniformly heat metals to high temperatures until they are melted.
Principle of High-Frequency Heating Equipment
A coil is wound around the object to be heated, and an AC power source is connected to the coil via a high-frequency oscillator. When the metal to be heated is inserted into the coil, eddy currents are generated on the surface of the metal, and the metal is heated by the Joule heat generated by the current.
In principle, only metals can be heated directly, but it is also possible to heat water indirectly by heating the metal to the point that it does not melt and bringing it into contact with the water. Of course, other individual substances can be used instead of water.
In addition, the heat input can be controlled relatively easily by adjusting the input value of the high-frequency oscillator, and when the metal is melted, eddy currents continue to flow in the molten metal itself, which also acts as a self-stirring force.
How to Select High-Frequency Heating Equipment
If you need to heat metals in a clean environment, we recommend that you consider installing High-Frequency Heating Equipment. In doing so, it is important to confirm that the shape of the coil for heat input is appropriate for the size of the material to be heated. If the metal to be heated does not fit inside the coil, it cannot be heated, of course.
It is also necessary to check the output of the high-frequency power supply according to how fast you want to heat the material. Since the heating device utilizes Joule heat from eddy currents flowing on the surface of the metal, if the maximum output power is low, it will take a reasonable amount of time to heat the metal.
Other Information on High-Frequency Induction Heating
1. Advantages of High-Frequency Induction Heating
The feature of high-frequency induction heating is that it heats by generating heat from inside the object to be heated through resistance heating using electromagnetic induction. The following five are the advantages of this feature.
Uniform Heating
Since this type of heating utilizes the electrical resistance of the object itself, the entire interior of the product is heated uniformly and evenly. This is a great advantage for materials with poor thermal conductivity or products with large heat capacity that require a long time to become uniformly heated by external heating.
Rapid Heating
High-frequency waves can be given instantaneously by controlling the transmitter, and since the heating is internal, the object to be heated can be heated rapidly. Compared to external heating, which takes time to equalize heat, this heating method offers superior productivity.
Selective Heating
Even if the object to be heated is a composite component consisting of several types of materials, only the portion of the component made of a material with high electrical resistivity can be selectively heated.
Atmosphere Selection and High Energy Efficiency
The furnace does not heat the heating element, atmosphere, or furnace structure as in the case of external heating by combustion, but only the object to be heat-treated generates its heat. Another major advantage is that high energy efficiency can be achieved because the heating is done only for the object to be heated without any waste.
2. Disadvantages of High-Frequency Induction Heating
High-frequency induction heating has four disadvantages, namely:
Expensive Capital Investment
High-frequency induction heating has high energy efficiency and low running costs but has the disadvantage of high initial capital investment costs due to the high cost of high-frequency power supplies and equipment to prevent electromagnetic radiation leakage.
Low Shape Selectivity
To heat an object uniformly and to the required temperature, it is necessary to make the electric field of the object to be heated uniform. Therefore, while there is no problem with highly symmetrical objects such as cylinders, it is difficult to uniformly heat objects with complex shapes such as square timbers and gears.
Local Heating
Localized heating in corners and other areas can lead to overheating, which can result in failure to provide the required properties, or in the worst case, can cause problems such as melting during processing.
Individual and Partial Heating
High-frequency induction heating is a method of heating the entire or only a portion of the material to be heat-treated using an arbitrarily shaped coil, so it is a one-piece flow process. Therefore, it is a one-by-one process, which has the disadvantage of reducing productivity depending on the product and production conditions, since it does not allow batch-type mass simultaneous processing like external heating.
3. Notification of High-Frequency Heating Equipment
High-Frequency Heating Equipment, as the name implies, uses a high-frequency power source. According to the Radio Law, Industrial High-Frequency Heating Equipment that uses a high-frequency power source of 10 kHz or higher requires, in principle, an installation permit. Installation permission is required before installation, so plan accordingly. Some manufacturers may apply on your behalf, so it is recommended that you confirm this when selecting a supplier.