Vega MINITRAC 31 Operating Instructions Manual page 9

Functional principle
MINITRAC 31 • Foundation Fieldbus
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3
Fig. 2: MINITRAC 31 - Application possibilities
1 Level measurement - Residue detection
2 Point level detection
3 Density measurement
4 Mass flow measurement
Further application possibilities are also the use as X-ray alarm or real
value correction.
If X-ray alarm is selected, the instrument detects radiation from exter-
nal sources. Possible external radiation sources can be, for example,
a weld joint test in a neighbouring facility or other radiometric instru-
ments.
When the instrument operates as real value correction it transmits the
real value to correct another radiometric sensor. The measurement
can thus be adapted perfectly to the situation in the vessel.
In radiometric measurement, a Caesium-137 or Cobalt-60 isotope
emits focussed gamma rays that are attenuated when penetrating
the tube wall and the medium. The NaI detector on the opposite side,
on a pipeline for example, receives the radiation. The intensity of the
radiation is dependent on the density of the measured media. The
measuring principle has proven to be very reliable in conjunction
with extreme process conditions because it measures contactlessly
from outside through the tube wall. The measuring system ensures
maximum safety, reliability and plant availability independent of the
medium and its properties.
3 Product description
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