RADWAG MAX 60 Moisture Analyzer - Manual (Page 73)

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Sample mass has considerable influence on repeatability of measurement
results obtained on a moisture analyzer. Relation between sample mass and
repeatability is presented in below table.
Sample mass Repeatability
to 2g
±0,24%
to 10g
±0,06%
over 10g
±0,04%
Data provided in the above table refer to a ideal and uniform sample, and an
assumption, that moisture content has completely evaporated from tested
sample during testing process, and the sample has not decomposed (e.g.
humid high-silica sand).
Measurement results are always subject to uncertainty related to a sample and
repeatability of used moisture analyzer. In practice, it means that obtained
measurement result may exceed repeatability values provided above.
13.3. Drying temperature
Drying temperature has the largest impact on drying time. Temperature value
depends on type of dried substance. Too low drying temperature causes too
low moisture content evaporation (under-dried sample), and consequently
unnecessary extending of measurement time. Too high drying temperature
causes burning of dried sample (sample overheating, chemical decomposition).
Drying temperature of traditional method (using a furnace) is specified in
applicable industry or company standards. Unless standards apply, then
temperature should be adjusted by tests.
On selecting the value of drying temperature, use the following procedure:
•
Determine moisture content in a sample
•
Determine temperature of substance chemical decomposition by tests
•
Compare result obtained on a moisture analyzer with the one of
traditional method
When drying a sample with high
humidity content, it is possible to
shorten measurement time by
selecting “Step” or “Quick” drying
mode. In such case, the majority
of moisture content is released
when drying temperature higher
than set. Only after some time,
the temperature is lowered to the set value, and maintained until completing
drying process.