Infrared

Infrared radiation

Although humans cannot see it, but can only perceive it as "heat radiation" on their skin, the infrared radiation is part of the optical radiation.

The IR radiation is therefore part of the electromagnetic spectrum.

The main supplier and thus the most important natural source of this heat radiation is the sun with 50% of the solar radiation arriving on the ground.

This has a decisive influence on the energy balance of the earth and global climate change, because not only the surface of the earth warmed by the sun emits heat radiation again, but also the natural and artificial gases contained in the atmosphere absorb the infrared radiation emitted by the earth. Radiation.

Conversely, every object that generates or emits heat (i.e. practically everything above absolute zero 0K or -273 ° C) - regardless of whether it is a living or an artificial heat generator - emits IR radiation.

The wavelengths that can be measured and the heat emitted depend on the heat of the object in question

Terms

The IR radiation is a component of the electromagnetic radiation spectrum

However, the spectral range cannot be clearly defined, since different divisions vary due to specific applications or certain physical phenomena.

A very common subdivision defines, for example:
● "Near infrared" (NIR) - wavelengths 780 nm to 3 µm
● "Middle infrared" (MIR) - wavelengths 3 µm to 50 µm
● "Far Infrared" (FIR) - wavelengths 50 µm to 1 mm.

Another classification (according to DIN 5030 Part 2) differentiates the NIR as follows:
● IR-A (780 nm - 1.4 µm) and
● IR-B (1.4 µ - 3.0 µm).

The limit at 3.0 µm is the absorption of IR radiation by water, which increases significantly above this value.

Therefore, according to the above The MIR and FIR classifications are combined to form the name IR-C.

IR radiation in industrial measurement

In opposite to humans, some animal species in the NIR range can perceive their surroundings via the eyes as well as other sensory organs or can even use this ability for foraging.

Non-contact measurement of surface temperatures has been technically feasible since around 1960.

At that time, however, expensive sensors and evaluation technology were a hindrance to widespread use in industrial measurement technology.

Only new manufacturing technologies and falling costs for production and materials helped this measuring method to make a breakthrough and so today there are various inexpensive handheld measuring devices for non-contact temperature measurement on offer.

These devices are used wherever conventional contact thermometers cannot be used or can only be used to a limited extent.

Such measuring devices only passively use the IR radiation from other heat sources, while, in contrast, IR radiation is actively used for moisture measurement using sensors from RGI Industriemessgeräte GmbH.