Far infrared heating technology has gone through three stages, taking three major steps, from silicon carbide, metal tubes, resistance bands, ceramics, semiconductors, enamel and other elements in the 1970s, to quartz tubes, gold-plated quartz tubes, microcrystalline glass lamps and other elements in the 1980s, and then to far infrared directional strong radiators. Among them, far infrared heating technology was limited to the medium temperature heating field of 0-450°C in the 1970s, and reached the medium temperature heating field of 600-750°C in the 1980s. In the early generation of far infrared heating ovens and drying ovens, although radiation was emphasized as the main heating method, part of the heat energy was still transferred through conduction and convection, so the ovens and drying ovens were required to be sealed and insulated. The far infrared directional strong radiator successfully developed in the mid-1990s achieved a new breakthrough in the electric-to-radiation conversion efficiency, with an efficiency of over 78%, a normal emissivity greater than 92%, a thermal response time of less than 2 minutes, and an adjustable operating temperature between 60°C and 900°C, without the need for enclosed ovens or drying ovens. The emitted hot photon beam is uniformly distributed in the radiation plane, overcoming the problem of uneven temperature distribution in various domestic infrared heating elements, providing the necessary conditions for promoting world-class open rapid drying machines in China. After decades of development, far infrared heating technology has achieved gratifying results. Under the current severe power shortage in China, improving the level of far infrared heating is of great significance in energy saving and improving the quality of heating and drying materials.
Technical Characteristics and Application Status
Compared with traditional heating methods such as steam, hot air, and resistance, far infrared heating technology has the following advantages:
(1) Internal heating, fast heating speed, and energy saving. It is reported that compared with traditional heating methods, far infrared heating improves production efficiency by 20% to 30%, saves electricity by 30% to 50%, and saves other energy by about 30%. The reason is that the radiant energy emitted by the radiator is all or mostly concentrated in the absorption peak band of the material, so most of the radiant energy is absorbed, achieving good matching and thus achieving energy-saving effects.
(2) Easy operation. Far infrared heating equipment has a simple structure, is easy to install, operate, and maintain. It only requires selecting appropriate radiation elements according to the raw materials and designing a suitable drying oven.
(3) Low pollution and high safety. Since far infrared heating is radiation heating, it does not pollute the environment, and the electric heating quartz tube has high safety and low harm to the human body.
(4) Easy temperature control. Because far infrared heating equipment uses automatic instrument control, it is conducive to controlling the heating temperature.
(5) Improved product quality. Far infrared rays have a certain penetration ability, allowing the internal and surface molecules of the material to simultaneously absorb radiant energy, generating a self-heating effect, causing water and other solvent molecules to evaporate, and heating evenly, avoiding deformation or qualitative change caused by uneven thermal expansion.
Given the significant advantages of far infrared heating technology, it has been widely used in the heating, melting, drying, shaping, consumption, and curing processes of many products or materials such as paint, plastic, food, medicine, wood, leather, textiles, tea, and tobacco. With the increasing variety and quantity of far infrared products, its application fields are also expanding. Far infrared heating technology has increasingly attracted people's attention and has been widely applied.
