Drying Temperature; Recommendations / Guidelines - KERN and SOHN DAB-BA-def-1813 Mode D'emploi

13.7 Drying temperature

The temperature has to be selected in a manner that the sample is not decomposed
or changes its chemical structure. But on the other hand if the temperature is too low,
drying time may be unnecessarily extended.
Bear in mind the following factors when setting the drying temperature:
Surface of the sample:
Compared with powdery or grainy samples, liquid and spreadable samples have a
smaller surface for the transmission of heat energy.
The use of a glass fibre filter improves the heat application.
Colour of sample:
Light-coloured samples reflect more heat radiation than dark ones and therefore
require a higher drying temperature.
Availability of volatile substances:
The better and faster the water or other volatile substances can be disposed, the
lower a drying temperature is required. If water is difficult to get to (e. g. in
synthetics), it has to be calcined at high temperatures (the higher the temperature,
the higher the water vapour pressure).
Results equivalent to other moisture analysing methods (e. g. drying chamber) can
be achieved by experimentally optimising the setting parameters such as
temperature, heating level and shutoff criteria.

13.8 Recommendations / Guidelines

Prepare standard sample:
Crush sample, as required, and spread it evenly in the aluminium dish.

Prepare special samples:
For sensitive or hard to spread test materials (e. g. mercury) a glass fibre filter

is available for use.
Spread sample evenly on glass fibre filter and cover is with a second glass

fibre filter.
The glass fibre filter is also useful as a protection when splashing materials

are dealt with (each splash falsifies the final result).
You will find examples taken from actual use in our application manual, available
from the KERN home page (www.kern-sohn.com).
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