The microwave oven is very common in our life, and it has a great influence on our life. It can not only ensure that we can eat hot food quickly, but also thaw frozen food quickly. It is conceivable how amazing the microwave oven is and how important it is in our lives. The microwave oven can realize these functions, mainly relying on the microwave heater, but few friends know about the microwave heater. The following small series will share the knowledge about the microwave heater in detail.
what is a Microwave heater
microwave? Heating) is the process of heating an object by using the energy characteristics of microwave.
microwave has obvious characteristics such as short wavelength (1m~1mm), high frequency (3MHZ~3GHZ), quantum characteristics and so on. Microwave technology is widely used in radar, navigation, multi-channel communication, remote sensing and television. Since 196s, people have gradually applied microwave heating technology to physical processing such as paper, wood and resin extrusion. In recent years, the introduction of microwave heating technology into the production process of microwave molybdenum industry can not only effectively improve the conversion rate and selectivity of the reaction, but also reflect many advantages such as energy saving and environmental protection. As one of the means to realize green technology, it has attracted wide attention.
principle of microwave heater
microwave is a form of energy (not heat), but it can be converted into heat in a medium. The reaction of materials to microwave can be divided into four situations: (1) penetrating microwave; (2) reflect microwave; (3) absorbing microwaves; (4) partial absorption of microwave.
generally, in the field of energy processing, the materials to be processed are mostly dielectric materials, and the dielectric materials usually absorb microwave energy to varying degrees, and the coupling of dielectric materials and microwave electromagnetic fields will form various power dissipation, thus achieving the purpose of energy conversion. There are many ways of energy conversion, such as ion conduction, dipole rotation, interfacial polarization, hysteresis, piezoelectric phenomenon, electrostriction, nuclear magnetic vibration and ferromagnetic vibration, among which ion conduction and dipole rotation are the main principles of microwave heating. Microwave heating is a kind of heating method which depends on the absorption of microwave energy by objects and converts it into heat energy, so that the whole body can be heated at the same time, which is completely different from other conventional heating methods. The traditional heating method is based on the principles of heat conduction, convection and radiation to transfer heat from the outside to the material, and the heat is always transferred from the outside to the inside to heat the material. There is inevitably a temperature gradient in the material, so the heated material is uneven, resulting in local overheating of the material. The microwave heating technology is different from the traditional heating method. It generates "internal friction heat" through the high-frequency reciprocating motion of dipole molecules inside the heated body, which raises the temperature of the heated material. Without any heat conduction process, the inside and outside of the material can be heated at the same time, and the heating speed is fast and uniform, and the heating purpose can be achieved only by one-tenth or one-tenth of the energy consumption of the traditional heating method. Theoretically, the amount of heat generated by a substance in a microwave field is closely related to the kind of substance and its dielectric properties, that is, microwave has the characteristic of selectively heating the substance.
Features of microwave heater
Uniform heating and high speed
The general heating method heats the surface of an object by heating the surrounding environment, and then conducts the interior of the object by heat radiation or hot air convection. This method has low efficiency and long heating time.
the biggest feature of microwave heating is that the microwave is generated inside the heated object, and the heat source comes from the inside of the object, so the heating is uniform, which will not cause the phenomenon of "uncooked outside coke", which is conducive to improving the product quality. At the same time, due to "simultaneous heating inside and outside", the heating time is greatly shortened, and the heating efficiency is high, which is conducive to improving the product yield. The inertia of microwave heating is very small, which can realize the rapid control of temperature rise and fall and is beneficial to the automatic control of continuous production.
selective heating
The heat generated by microwave heating is closely related to the loss of the heated object. The dielectric constant of various media is in the range of .1 to .5, so the ability of various objects to absorb microwave is very different. Generally speaking, a medium with a large dielectric constant is easy to be heated by microwave, while a medium with a small dielectric constant is difficult to be heated by microwave. This is the characteristic that microwave can selectively heat objects.
Timely control and sensitive response
Conventional heating methods, such as steam heating, electric heating, infrared heating, etc., need a certain time to reach a certain temperature, and the temperature will drop for a long time when there is a fault or heating stops. However, microwave heating can quickly adjust the microwave power to the required value within a few seconds and heat it to an appropriate temperature, which is convenient for automatic and continuous production.
The above is the knowledge about microwave heaters in microwave ovens. I hope our sharing will be helpful to everyone, especially those who don't know about microwave heaters. The effect of microwave heater in the heating process is very good. And the heat it generates is closely related to the loss of the heated object. What we have shared about microwave heaters above is also very detailed. I hope that friends who are interested in microwave heaters can pay more attention to what we have shared above.