How is the ceramic heating plate heated
In any heating device, the heat source is transferred to the heated object in three forms of convection, radiation and conduction. Heat conduction refers to the three forms of heat transfer phenomenon in which there is no relative displacement of various parts of an object or when different objects are in direct contact with the thermal movement of microscopic particles such as material molecules, atoms and free electrons. Convection is a phenomenon that relies on fluid movement to transfer heat from one place to another. Whether it is heat conduction or convection, heat must be transferred through direct contact with hot and cold objects or relying on conventional substances as a medium. But the mechanism of heat radiation is completely different, it relies on the surface of the object to emit visible and invisible rays to transfer heat. The transmission speed of radiant heating is fast, and it does not pass through any medium, thus greatly reducing the loss in the process of heat energy transmission, thereby improving the utilization rate of heat energy.
In far-infrared heating technology, radiant heating is the main focus. When the far-infrared rays are irradiated to the heated object, part of the rays are reflected back, and part of the rays are penetrated. When the emitted far-infrared wavelength is the same as the absorption wavelength of the heated object, the heated object absorbs a large amount of far-infrared rays, which makes the molecules and atoms inside the object "resonate"-produce strong vibration and rotation, and the vibration and rotation make the object The temperature rises to achieve the purpose of heating. To use this technology to improve heating efficiency, it is important to pay attention to matching radiation.
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The so-called matched radiation means that when the frequency of the infrared radiation irradiated on the object is the same as the vibration frequency of the molecules of the material constituting the object, the molecules will resonantly absorb the infrared radiation energy, and at the same time, through the transfer of energy between molecules, the internal energy (vibration) Energy and rotational energy) increase, that is, the average kinetic energy of molecules increases, which is manifested as an increase in the temperature of the object. The main meaning of matched absorption is that the frequency of the selective radiation emitted by the infrared heater is consistent with the vibration frequency of the heated substance molecule itself, and the resonance absorption caused at this time is the matched absorption.
Matching absorption is of great significance to the heating of thin layers, such as baking varnish, plastic processing and dehydration and drying of certain salts. Heating of thick materials is of little significance, because far-infrared rays have very low penetrating ability to general substances, generally only penetrating between a few microns to a few millimeters. Even if the energy is not absorbed by surface molecules, it will be absorbed by the object. Absorbed, in this case mainly try to reduce the reflectivity, in order to increase the absorption rate. Due to the requirements of baking quality or processing technology, some heated materials are expected to be heated at the same time inside and outside, such as: drying of wood, hope that the inside and outside are heated at the same time to avoid cracking; the melting of plastic also requires the inside and outside to be heated at the same time to avoid excessive external temperature. High and aging. Therefore, the non-matched absorption should be considered when heating these materials, so that a part of the far infrared rays can penetrate into the body to achieve the purpose of uniform heating.