Ohaus MB45 MOISTURE ANALYZER Manual - Manual (Page 47)

MB45 45
8. How to obtain the best results
Following your first practical work with the Moisture Analyzer, in this section you will find important
information on how to obtain optimum results. You will learn what parameters influence the
measurement process and how you can match the instrument optimally to your particular measurement
test.
8.1 Measurement principle of the Halogen Moisture Analyzer
Your instrument performs measurements based on the thermogravimetric principle, i.e. the moisture is
determined from the weight loss of a sample dried by heating.
The Ohaus Moisture Analyzer comprises two instruments: a precision
balance and a dryer unit. In contrast to other thermogravimetric
methods (drying oven, infrared, microwave), the Halogen Moisture
Analyzer operates with a halogen dryer unit. This ensures fast
heating of the sample and thus guarantees rapid availability of the
measurement results.
In addition to thermogravimetric methods, chemical and electrical methods for moisture determination
are also common. A familiar chemical method is Karl Fischer in which the water content is determined
by titration. This method is particularly suitable for determination of the water content of liquids or for the
detection of very small amounts of water (ppm range) in solid and liquid samples.
Regardless of the measurement method used, the quality of the measurement stands or falls by the
preparation of the sample and a correct choice of the important measurement parameters:
— Sample size
— Type of sample
— Drying temperature
— Drying time
In practice, however, not only the quality of the measurement results, but also the speed of the
measurement process is important. Thanks to its drying principle (with the heat generated by a halogen
radiator), the Halogen Moisture Analyzer is very fast. The drying speed can even be increased further
through optimum settings of the instrument.
The optimum drying temperature and the drying time are dependent upon the nature and size of the
sample and the desired accuracy of the measurement results. These can be determined only by
experiment.