Sartorius YDK03 Betriebsanleitung Seite 13

Adhesion of Liquid to the Wire
When the sample holder (or sieve) is
immersed in liquid causing buoyancy,
liquid travels up the wire because of
adhesion forces and generates an addi-
tional weight in the range of a few
milligrams�
Since the sample holder (or sieve) is in the
liquid causing buoyancy during both
weighing in air and weighing in liquid, and
the balance is tared at the beginning of
each measuring procedure, the effect of
the meniscus can be disregarded�
To reduce the surface tension and the
friction of liquid on the wire, add three
drops of a tenside (Mirasol Antistatic or an
ordinary dishwashing detergent) to the
distilled water in the beaker�
Because of the liquid travelling up the wire,
the weight may slowly change even after
the stability symbol "g" appears�
Therefore, read off the weight immediately
after the "g" is displayed�
Air Bubbles
The measuring error caused by air bubbles
adhering to the sample can be estimated in
the following manner� An air bubble with a
diameter of 0�5 mm causes an additional
buoyancy of less than 0�1 mg when a
sample is weighed in water� An air bubble
diameter of 1 mm causes additional
buoyancy of 0�5 mg and an air bubble
diameter of 2 mm causes approx� 4�2 mg
additional buoyancy� Larger air bubbles
must be removed with a fine brush or other
utensil�
You can also wet the sample in a separate
container before you weigh it�
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