13 General issues concerning moisture analyzing
13.1 Application
Wherever in a manufacturing process moisture is extracted from or added to
products, fast determination of the moisture content is immensely important. For
innumerable products the content of moisture is a quality feature as well as an
important cost factor. When dealing with industrial or agricultural products as well as
chemical products or products from the food industry, fixed limits often apply for the
content of moisture, which are defined in supply agreements and standards.
13.2 Sample material
Samples with the following characteristics can generally be analyzed easily:
♦ Grainy to powdery solids that can be poured
♦ Thermally stable materials that emanate the moisture to be analyzed easily,
without evaporating the other substances
♦ Liquids that evaporate to dry matter without formation of film
It may be difficult to analyze a sample that is:
♦ Viscous/sticky
♦ Tends to form a crust or a film when drying
♦ Disintegrates easily when heated or emanate various
components
13.3 Sample preparation
In many cases, special sample preparation is not necessary. However, coarse solids,
e.g. kernels or grains should be ground.
The duration of the drying process as well as the achievable exactness are
considerably influenced by the distribution of the sample. This results in two
requirements working in opposite directions:
The lighter the poured material, the shorter is the time the drying process will take;
and the heavier the poured material the more exact the result will be.
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