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Section 8 - How to obtain the best results
Ramp drying
Ramp drying is selected if substances are
not stable on exposure to the full heating
power of the halogen radiator at the start.
In ramp drying, sensitive samples are
prevented from decomposition by the
gentle heating. Ramp drying can also be
used successfully with substances which
form a skin.
Fast drying
The fast drying program is suitable for
samples with a moisture content between
5% and 15%. In fast drying, the radiator
power exceeds the set temperature value
during the first minute following the start of
drying. This compensates the endother-
mic heat of vaporization and accelerates
the drying process. Note that the sample
must contain sufficient moisture during the
first minute to cool it.
Step drying
The step drying program has a use similar
to that of fast drying. The duration of the
excessive temperature stage and the
temperature value are freely selectable. It is
used primarily with samples with a moisture
content greater than 15%.
A alternate application possibility lies in the
selective determination of the moisture at
different temperatures. Gypsum, for ex-
ample, releases only its surface water at 50°C, whereas the water of crystallization can not be separated until
168°C. With this drying program, it is thus possible to determine the surface water and the water of crystalliza-
tion separately within the same measurement by a controlled temperature profile.
Temperature profile
Final
temperature
Ambient
temperature
Fast drying
Time
Start
Temperature profile
Final
temperature
Ambient
temperature
Step drying
Time
Start
Temperature profile
Final
temperature
Ambient
temperature
Ramp drying
Time
Start
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