1. Resistance heating
It is to use the Joule effect of current to convert electric energy into heat energy, so that it can heat the object. It can be divided into direct and indirect. The former belongs to internal heating, so its thermal efficiency is high, and the operation is simple and convenient, while the latter, due to requirements The resistivity and the temperature coefficient of resistance are small, so in the process of use, it is necessary to use a pressure regulating device, which can generally be used in some special occasions.
2. Induction heating
It is the thermal effect formed by the induced current generated by the conductor, so that the conductor itself is heated, and it has three kinds of power frequency, medium frequency and high frequency.
Induction heating can not only uniformly heat the object as a whole, but also heat the surface layer, and can also perform any local heating, so it is still used very much.
3. Media heating
The high-frequency electric field is used to heat the insulating material, so its heating object is mainly a dielectric. In industry, it can heat gel, paper, wood, etc., and plastic, etc. For some homogeneous materials, It can be heated as a whole.