RADWAG MAX 60 Moisture Analyzer - Manual (Page 71)

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can be prepared for measurement otherwise than grinding, any possible
moisture content loss should be calculated.
Use of high-silica sand
Ensuring optimum substance drying requires that a sample has the largest
possible surface for moisture content vaporization. Test results of moisture
content in substance which surface has a form of a shell (e.g. glucose syrup) or
doughy (e.g. butter), can be much more reliable if a sample is mixed with a
dried high-silica sand (improvement of measurement accuracy and
repeatability).
When testing a substance by mixing it with high-silica sand it is recommended
to use a disposable drying pan with higher edges due to larger volume of a
sample to be tested).
Grease in a form of paste or melting substances
Such substance requires testing with use of a filter made of glass fiber, which
considerably increases active evaporation surface by separating the substance
between the fiber. Initial filter drying is necessary only in case of measurements
which require very high accuracy.
Liquid substances
It refers to liquid substances, which by creation of drops on their surface,
caused by surface tension, may render difficulties in drying process. In such
cases, it is proved to use a glass fiber filter to shorten measurement time. The
filter causes separating tested liquid around the fibers, and increasing active
evaporating surface. Initial filter drying is necessary only in case of
measurements which require very high accuracy.
Substances with structure of leather or temperature sensitive
In case of such substances it is proved to a glass fibre filter. While testing, a
substance is placed on a drying pan, and sample surface is covered with a
filter, which protects the sample from direct heat radiation. In such case, the
sample is heated by convection (which is milder than radiation).
Substances containing sugar
The surface of such substances often may caramelize during testing
procedure. Therefore, it is recommended to use thin layer of a sample, and
moderate drying temperature.
Sample distribution on drying pan:
Loose materials
Dried in their natural state, i.e. in their natural form or disintegrated. Sample
disintegration causes smaller dispersion
between the following measurements.
Sample mass should not be too high, and
the sample should be evenly spread on
whole surface of the drying pan.