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Get ready to start a measuring campaign
4.2.5
Check the HYPROP
Wrap a dry paper towel around one ceramic tip to create a
momentary dry ceramic surface. Now create an air current around
the ceramic cup, e. g. by waving a sheet of paper. The reading
should rise to -800 hPa within seconds. If this is the case, the
Tensiometer is filled correctly. Do the same with the second tip.
To find out the maximum measuring range of the Tensiometers take
a bottle filled with water and hold the ceramic tip into the headspace
of the bottle. When you move the ceramic away from the water
surface the air gets dryer and the suction rises.
Hold the ceramic close to the water surface so the tension reading
will rise slowly. Depending on the filling quality the value will reach
-85 to -450 kPa. Then, the value will rapidly drop to the vapor
pressure (around -90 kPa depending on the altitude). Now
immediately put some water on the ceramic and cover the ceramic
with the protective rubber cap which should be halfway filled with
water. It will take one day until the Tensiometer will reach its initial
value.
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