OHAUS MB45, Инструкция по эксплуатации

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How to obtain the best results - Section 8
The following procedure is suggested for selecting the temperature.
— Estimate moisture content of the sample.
— Determine the decomposition temperature of the sample by experiments.
— Compare the measurement results with the reference method if one exists.
— If an excessive amount of moisture is evolved, lower the drying temperature. If the experimental results are
too low, the drying temperature was possibly too low or the drying time too short.
With samples which have a high moisture
content, it is possible to shorten the measure-
ment time by selection of the step or rapid
drying program. Here, the greatest part of the
existing moisture is separated at an elevated
temperature.
The drying temperature is then lowered and
kept constant until the end of drying. The
excessive temperature is used for rapid vapor-
ization of the moisture, but the effective sample
temperature does not exceed the boiling temperature of the liquid (cooling effect through endothermic vaporiza-
tion). In certain cases, local heating and decomposition could still occur at the sample surface.
8.4 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 selec-
tion of a more complex drying program
may be advantageous.
Measurement time
long
short
Drying temperature
Temperature profile
Final
temperature
Ambient
temperature
Standard
Time
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