Selection Of The Drying Program - OHAUS MB120 Instruction Manual

MB120
For MB120, OHAUS provides a temperature guide to estimate the proper temperature for
reference. Please see section 9.2 for details.
9.4

Selection of the drying program

Various drying programs are available in the Halogen Moisture Analyzer. There are four
programs which control the temperature profile. They are:
— Standard drying program
— Fast drying program
— Ramp drying program
— Step drying program
Standard drying
Standard drying is suitable for precise
determination of the moisture content
of most substances. For special cases
or for time optimized measurements,
the selection of a more complex drying
program may be advantageous.
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 endothermic
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%.
An alternate application possibility lies in the selective determination of the moisture at
different temperatures. Gypsum, for example, releases only its surface water at 50°C,
T emperature profile
Final
temperature
Ambient
temperature
Start
T emperature profile
Final
temperature
Ambient
temperature
Start
T emperature profile
Final
temperature
Ambient
temperature
Start
T emperature profile
Final
temperature
Ambient
temperature
Start
EN-53
Standar d
Time
Ramp drying
Time
Fast drying
Time
Step drying
Time