OHAUS MB23 Guide De L'utilisateur page 8

EN-6
Types of Samples
Pasty, fat containing and melting substances
Use a glass fiber filter to increase the surface area of these types of samples (e.g., butter). The moisture in these substances
is more uniformly distributed through the filter. The increased surface area results in faster and more complete vaporization
of the moisture.
Liquid substances
Liquids (e.g., dispersions) tend to form drops on the test pan, which prevents rapid drying. Use of a glass fiber filter shortens
the drying time significantly as the filter distributes the liquid sample over a larger surface area.
Skin-forming and temperature sensitive substances
Formation of a film on the surface of these samples can prevent complete determination of moisture. Using a glass fiber filter
to cover the sample allow gentler and more beneficial heating, improving reproducitility.
Sugar-containing substances
Samples containing large amounts of sugar tend to caramelize. Ensure that a thin and uniform layer is applied and a moderate
temperature selected. The sample can also be covered with a glass fiber filter that improves reproducitility.
The following substances present risk of fire, explosion, damage or injury.
Should there be any uncertainty regarding the safety of a substance, always perform a careful risk analysis.
In such cases, never leave the Analyzer unattended.
Volatile substances
With volatile samples, rapid application of the sample on the test pan is advisable, to limit the moisture from escaping before
the initial weight is recorded. These substances also include samples treated with solvents, and substances which contain
solvents or release flammable or explosive vapors. Work at drying temperatures low enough to prevent the formation of flames
or an explosion. Always work with small samples (maximum 1g).
Poisonous and toxic substances
Substances which contain toxic or caustic components should only be dried in a fume hood.
Corrosive substances
Substances which release corrosive vapors when heated (e.g. acids) should be tested in small amounts. The vapors can
condense on the Analyzer parts causing corrosion.
5. MAINTENANCE
Weight Calibration
Weight calibration is rarely required. Moisture analyzers use relative weight values to determine the results, so a minor offset
from the absolute weight has little effect on accuracy. OHAUS moisture analyzers have rugged, high quality temperature
stabilized weighing modules that retain their calibration over long periods of time.
(1) Remove any load on the Pan Support including the sample pan.
(2) Press and hold Cal while in the Weigh mode. "CAL" will appear followed by "50.00g".
(3) Place a 50g calibration mass on the Pan Support. The display will show "-----".
(4) Remove the mass when "--0--" is shown on the display. The display will show "-----".
(5) The Analyzer will return to Weigh mode when calibration is complete.
Note: Pressing START will cancel the calibration without saving the changes.
Temperature Calibration
Temperature calibration is rarely required under normal use. If the heating elements become dirty, the usual setting may no
longer produce the same results. A temperature calibration can correct for these changes.
Use only the OHAUS Temperature Calibration Kit (accessory) to perform temperature calibration. Damage
to the Analyzer can occur if using other methods.
(1) Remove the Pan Support for the temperature calibration to start.
(2) Place the OHAUS Temperature Calibration Kit into the temperature chamber (see Kit Instructions). Close Cover.
(3) Press and hold Cal until "Cal" is displayed. When Cal is released "TC100" will appear and the heater turns on.
(4) After 15 minutes, the unit will beep and blink "100" on the display.
(5) Read the thermometer on the Temperature Calibration Kit and press Set to change and match the displayed value
to the thermometer reading.
(6) Press Tare to enter the value. The display will show "TC160" as the heater turns on again.
MB23 / MB25