optris PI 400 LW, Руководство оператора

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optris PI LightWeight Kit
– E2013-04-B
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Emissivity
Definition : The intensity of infrared radiation, which is emitted by each body, depends on the temperature as
well as on the radiation features of the surface material of the measuring object. The emissivity (ε – Epsilon)
is used as a material constant factor to describe the ability of the body to emit infrared energy. It can range
between 0 and 100 %. A “blackbody” is the ideal radiation source with an emissivity of 1,0 whereas a mirror
shows an emissivity of 0,1.
If the emissivity chosen is too high, the infrared thermometer may display a temperature value which is much
lower than the real temperature
– assuming the measuring object is warmer than its surroundings. A low
emissivity (reflective surfaces) carries the risk of inaccurate measuring results by interfering infrared radiation
emitted by background objects (flames, heating systems, chamottes). To minimize measuring errors in such
cases, the handling should be performed very carefully and the unit should be protected against reflecting
radiation sources.
Spectral emissivity of some materials
1 Enamel, 2 Plaster, 3 Concrete,
4 Chamotte
Capability of an object to
emit radiation