Operating instructions CellaTemp PKx 6x
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• Small objects with medium and high temperatures can also be easily and
accurately measured�
• When measuring materials with low specific heat, a non-contact method does
not induce heat loss which would distort the temperature reading (as is the
case with contact temperature probes)� Non-contact temperature detection
is ideal with corrosive molten materials for which the use of thermocouples is
hardly feasible�
• Last but not least it is also possible to measure the temperature of voltage-car-
rying objects�
15.2 Measurements at Black Bodies (Cavity Radiators)
A black body or a black radiator is used to calibrate radiation pyrome-ters� This
black body is designed in a way that its radiation does not
depend on material characteristics, but only on its temperature� A black body emits
at any wavelength the maximum energy possible for the specific temperature� Real
bodies do not have this ability� In other words, a black body completely absorbs
the radiation without reflection or transmission losses� The spectral emissivity
coefficient e(*) of a black body is equal to 1 or 100 %� The emissivity coefficient
indicates the ratio of radiation of a real body (target) to the radiation of an ideal
black body�
ε(λ): Emissivity coefficient of the object’s surface (targeted spot) at wavelengh λ
M: radiant energy actually emitted by a real object
M
S
: radiant energy emitted by a black body (perfect radiator)
Most burning, annealing and hardening furnaces emit a radiation of nearly ‚1‘
which corresponds to the conditions of a black body if the aperture through which
the measurement is made is relatively small�
15.3 Measurements of Real Radiators
Real radiation sources are characterized by the relation of the emitted radiation to
the radiation of a black body with the same temperature� Measurements outside a
