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MRS-BA-defsi-0410
5.1.1 Adjusting to the existing measuring
process
The MRS 120-3 moisture analyzer is frequently used in place of
other drying techniques (like the drying oven) because it is easier to
operate and offers shorter measuring times. Consequently, the
conventional measuring process has to be adapted to the MRS
120-3 so that comparable results can be achieved.
•
Performing a parallel measurement
Lower temperature setting in the MRS 120-3 than in the drying
oven technique
•
The result achieved with the MRS 120-3 does not match the
reference
– Repeat the measurement with a changed temperature setting
–
Vary the switch-off criterion
•
Adapting with the calibration curve or factor
5.2 Sample preparation
Prepare one sample at a time for measurement. This prevents the
sample exchanging moisture with the ambient surroundings. If a
number of samples have to be taken simultaneously, they should
be packed in air-tight containers so as to ensure that they do not
change while they are in storage.
Distribute the sample
evenly
and
thinly
on the weighing pan in
order to achieve reproducible results.
If it is applied unevenly, this causes an inhomogeneous distribution
of heat in the sample being dried, resulting in incomplete drying or
an extension to the measuring time. If the sample is piled up, it
heats up with greater intensity in the upper layers, causing
combustion or encrustation to occur. The high layer thickness or
possible formation of a crust prevents the moisture from escaping
from the sample. This residual moisture means that measurement
results achieved this way are not verifiable and reproducible.
Solids:
•
Distribute powder samples evenly on the weighing pan.
•
Make course samples smaller using a mortar or grinder. Do not
expose the sample to any heat while you are grinding it as this
will lead to a loss of moisture.
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