What is Infrared Drying ?
Infrared heating or drying involve a heat transfer by radiation between a hot element and a material at lower temperature that needs to be heated or dried. The peak wavelength of the radiation is dependant of the temperature of the heated element.
Thermal radiation is considered to be infrared in the electromagnetic spectrum between the end of the visible, 0,78 µm, and 1000 µm.
In general, infrared radiation is split into 3 main categories, in function of the wavelength peak of the radiation:
- Short-wave IR (SW): from 0,78 µm to 2µm
- Medium-wave IR (MW): from 2µm to 4µm
- Long-wave IR (LW): from 4µm to 1000µm
The heat energy is directly transfered from the infrared source to the product to be heated without the need of an intermediate such as air or water. All materials will absorb, reflect and allow a fraction of the infrared spectrum to pass through. It is important to select the infrared emitters with the suitable spectra according to the product to have an optimized absorption of the radiation that will be subsequently converted into heat.
In an infrared system, the hot elements consist in gas emitters or electrical lamps which are aligned in order to create a heating surface. Thanks to its high efficiency, a lot of industrial production processes use the infrared heat for drying, pre-heating, curing, scorching etc.
Infrared emitters offer efficient heat and much more advantages compared to other conventional heat technologies:
- No direct contact with the product to be heated or dried,
- High drying/heating rate with the product to be heated,
- Infrared radiation can be focused where it is needed in a defined time,
- Infrared emitters can be adjusted precisely to the material properties/geometry,
- Cost savings thanks to high overall efficiency and optimal infrared heaters lifetime,
- Possibilities to link the IR system with air drying sections to recover the energy.
Download: Infrared drying and heating technologies