What is infrared radiation?
Infrared radiation is also called thermal radiation, is part of the optical radiation and therefore a part of the electromagnetic spectrum. It joins the visible light in the direction of longer wavelengths. The most important natural source of infrared radiation is the sun. Infrared radiation accounts for 50 percent of the solar radiation that reaches the earth’s surface. In addition, the earth heated by solar radiation emits infrared radiation.
We ourselves experience infrared radiation every day. The heat we feel in sunlight or in front of a fire, a radiator or a hot asphalt surface is infrared radiation. Even though our eyes cannot see it, the nerves in our skin perceive it as heat.
Infrared radiation can be divided into three main categories:
- near infrared (NIR): This range is close to the visible light spectrum and has shorter wavelengths. It is often used in technologies such as remote controls, optical communication systems, and near-infrared spectroscopy devices.
- mid-infrared (MIR): This range includes longer wavelengths and is often used in applications such as thermal imaging cameras, sensor systems, and industrial processes for temperature monitoring.
- far infrared (FIR): This range has the longest wavelengths and is mainly used for therapeutic and wellness applications, such as infrared saunas or heat therapy equipment.
Infrared radiation interacts with matter in different ways. It can be reflected, absorbed or transmitted by surfaces, depending on the properties of the material. Therefore, infrared radiation is used in various fields such as physics, chemistry, medicine, communications and industry.
Infrared radiation also has importance in environmental science. It enables the study of heat distribution and radiation from the earth’s surfaces, atmosphere and oceans, which is of great importance for the study of climate and climate change.
What role does infrared radiation play in process engineering?
Infrared radiation plays an important role in process engineering, especially in areas related to heat transfer, drying, heating and thermal processes:
- drying: Infrared emitters are often used in drying plants to remove moisture from materials. The infrared radiation heats the material, causing the bound water to evaporate. This process is widely used in industries such as food processing, paper making and textile.
- heating: infrared emitters are used to heat materials quickly and evenly. This is particularly useful in plastics processing, where plastics need to be melted, or in the manufacture of glass or metal, where precise and efficient heating is required.
- heat curing: in process engineering, infrared radiation is often used to cure coatings, paints or adhesives by applying heat. This allows faster curing compared to conventional methods and provides higher production speed.
- surface treatment: Infrared radiation is used to activate or modify surfaces. For example, infrared radiation can be used to improve the adhesion of coatings to certain surfaces or to pre-treat plastics before painting or printing.
- welding and joining: In process engineering, infrared radiation or laser technologies are used to weld or join materials by applying heat. This may be relevant in the plastics industry or in the manufacture of electronic components.
- temperature measurement: Infrared thermometers are used to quickly measure the surface temperature of materials or equipment components without contact. This allows monitoring of processes and control of temperature in real time.
The use of infrared radiation in process engineering offers advantages such as precise and controlled heat exposure, efficient energy utilization, fast process times and good adaptability to different materials and applications.