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5 Execution
5.1 Preparations
5.1.1 Filling the Pycnometer
Distilled water is designated as the reference fluid. The compati-
bility of the Pycnometer material (Plexiglas) must be guaranteed
if other fluids are to be used.
The following requirements must be observed for the reference
fluid:
Gas proportion
< 0.6 . 10
Electrical conductivity
0.1 µS / cm
Suspended particles
None
Temperature
Thermal equilibrium with environment
If necessary the water should be filtered and degassed with the
aid of ultrasound.
The Pycnometer must be filled with the fluid to approximately
one quarter full before the test specimen is introduced. Then tip
the test specimen / Pycnometer a little in order to remove any
air pockets.
The test specimen must be placed as centrally as possible in
order to prevent deviations due to eccentric positioning.
The Pycnometer is then filled up to the upper rim of the con-
tainer before being closed with the top section. The following
method is recommended for filling or emptying the Pycnometer:
Figure 4: Filling and emptying the Pycnometer
Finally, more fluid is added until the mirror is precisely in line
with the fill control capillary.
Thermal equilibrium of the Pycnometer with its environment
and content must be assured before measurement can begin.
For this purpose, the temperature of the reference fluid is
checked at various insertion depths for as long as is necessary.
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5.1.2 Prepare the Balance
The installation of the balance must meet the same conditions
that apply to the determination of the mass of weights. Particu-
lar reference is made to the requirements for a mass laboratory
at the place of installation – E2 or F1 depending on the accura-
cy required.
If there are no concentric positioning markings on the balance's
weighing pan, suitable markings should be applied in order that
the Pycnometer may be positioned as centrally as possible with
no significant deviation.
In accordance with the balance's operating conditions, it must
be connected to the electrical supply in stand-by mode for a
suitable length of time.
The characteristics of the balance must be recorded in advance
if the linearity deviations are to be included in the calculations
(please consult the explanations provided in the manual in
this respect).
The sensitivity of the balance must be adjusted before beginning
each measurement sequence. The calibration weight to be used
is described in the installation and operating instructions for
the balance.
5.1.3 Prepare Auxiliary Device
A lifting and tilting device is required when using the Pycnometer
for higher nominal values such as 20 or 50 kg. This device must
guarantee that the Pycnometer, and also the reference weights
in the case of the substitution method, can be placed as precisely
and smoothly as possible on the balance's weighing pan.
5.1.4 Reference Weights
In the case of the substitution method, the reference weights
and auxiliary devices required for lifting and positioning must be
available and ready. The reference weights must be well acclima-
tised in order to prevent thermal effects.
A difference of 100 g between the reference weights and the
Pycnometer is sufficient for the selection of the reference
weights.
5.1.5 Measuring Instruments for Climate Data
The measuring instruments for barometric pressure, air tempera-
ture and relative humidity must be ready for use.
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