Recording Of Desorption And Adsorption Curves - Novasina AW SPRINT Series Operating Instructions Manual

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You require the Sorption Isotherm Set SI, available as a separate acces-
sory, to record desorption and adsorption curves.
Recording the desorption curve Recording the desorption curve Recording the desorption curve
Recording the desorption curve Recording the desorption curve
For recording the desorption curve the product must always be more humid
than the 1st measuring point of the sorption isotherm.
• 1st measuring point e.g. 53 % rh, humidifying of the product with
humidity standard SAL-75.
• Place humidity standard, e.g. SAL-75, in measuring chamber.
• Put on SI ring and turn clockwise as far as it will go.
• Ascertain weight of the substance basket including weighing glass.
• Fill substance basket with the material to be tested and insert into SI ring
with tongs.
• Put on measuring head.
• Set setpoint temperature, e.g. 25 °C.
The conditioning process can be followed on the humidity display. Howev-
er, the value must lie above the first point to be determined.
After conditioning the product is more moist than the 1st measuring point.
• Remove the measuring head, SI ring and substance basket from
measuring chamber.
• Remove humidity standard SAL-T75 from measuring chamber and
insert humidity standard SAL-T53.
• Put on measuring head with SI ring and substance basket.
• After conditioning remove the substance basket from the measuring
chamber with pincers and place it in the weighing glass.
• Close weighing glass and weigh the test material.
The 1st point of the sorption isotherm has now been determined.
• Remove humidity standard SAL-T53 from measuring chamber and
insert humidity standard SAL-T33.
• After conditioning the weight loss is determined and hence the 2nd point
of the sorption isotherm is obtained.
This procedure is repeated with the desired humidity standards until the
test material is completely dried out.
Recording of the absorption curve Recording of the absorption curve Recording of the absorption curve Recording of the absorption curve Recording of the absorption curve
The measuring procedure is the same as for the recording of the desorption
curve except for the reverse order.
During the first operation, the product is dried (0 % water content) to
determine the dry weight.
The samples to be measured are then gradually humidified, and the weight
gains noted.
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