What is infrared (IR) radiation?
In our daily life, infrared radiation is everywhere, the greater the temperature difference between objects, the more obvious phenomena of radiation. Vacuum can be solar energy infrared radiation emitted by 93 million miles of space to Earth, which we absorb, to take us warm. When we stand before the mall’s food freezers, our body heat emitted infrared radiation absorbed by frozen food, we are very cool. Radiation effects in these two examples are very obvious, we can clearly feel the change and feel where it exists.
When we need to quantify the effect of infrared radiation, we need to measure the temperature of infrared radiation, this time is necessary to use infrared thermometer. Different materials, the performance of the infrared radiation characteristics are also different. Read the temperature using the infrared thermometer, we must first understand the basic principles of infrared radiation measurements and the specific characteristics of the tested materials, the infrared radiation.
Infrared radiation rate formula: rate = absorption rate of infrared radiation reflectance transmittance
No matter what kind of infrared radiation, once the issue will be absorbed, the absorption rate = emission rate. Infrared thermometer is read by the surface energy of emitted infrared radiation, infrared radiation device can not read the air loss of infrared radiation energy, the actual measurements, we can ignore the transmission rate does not count, so we get a The basic formula for infrared radiation measurements: infrared radiation rate = emission rate – reflectivity
Reflectance and emissivity is inversely proportional to the object reflecting the stronger the ability of infrared radiation, infrared radiation of its own ability to more weak. Visual methods commonly used can be broadly determine the reflectivity of an object the size of the new high reflectivity of copper and low emissivity (0.07-0.2), copper oxidized low reflectivity and high emissivity (0.6-0.7 ), because of heavy black copper oxide and even lower reflectivity, while the corresponding emission rate will be higher (0.88). Most painted surface emissivity is very high (0.9-0.95), while the reflectivity is negligible.
For most infrared thermometer, the only material being tested is the need to set the emissivity rating, the value is usually the default is 0.95, which for the measurement of organic materials or painted surfaces is sufficient.
By adjusting the infrared thermometer emissivity, can compensate for part of the surface infrared radiation energy shortage problems, especially metal materials. There is only near the surface of the measured object and reflect infrared heat radiation to be considered when the measurement of reflectivity.