Temperature Conditioning Of Sample; Automated Measuring Operation; Example Of Manual Measuring Operation - SCHOTT Instruments 541 Serie Manual De Instrucciones

6 Temperature conditioning of sample

After filling, hang viscometer with its stand, type no. 053 92 (in case of Ubbelohde viscometer with
cleaning tube) or type no. 053 93 (for Ubbelohde viscometer with TC sensors) into a Constant-
Temperature
Immersion Circulator of SI Analytics GmbH. For fully using the measuring accuracy of the viscometer, the
thermostatic bath should maintain the set temperature at a constant ± 0.01 °C which is possible with
SI Analytics GmbH constant temperature immersion circulators. Temperature differences of 0.1 °C
may cause an error of as much as 0.6 % in mineral oils. Measuring should take place only after an
equilibration time of approx. 10 minutes (depending on ∆ T between room and measuring temperatures).
This equilibration time can be preprogrammed for the AVS measuring systems (see specific operating
instructions).
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Automated measuring operation

The automated viscosity-measuring instruments by SI Analytics GmbH (see AVS brochure) replace the
above described manual operation of viscosity measurement. Subjective measuring errors are eliminated,
and the efflux times measured appear as a print-out. For carrying out the measuring, we refer to the
operating instructions of each specific instrument. The Ubbelohde viscometer with TC sensors and
cleaning tube can be used in all instruments of the AVS types.
8 Example of measuring operation
Required accuracy of measurement
for test temperature 10 ... 30 °C:
Required temperature stability of thermostat
Accuracy of reading on telltale thermometer
Equilibration time
Allowable deviation from vertical suspension of viscometer
1
Minimum flow time )
in capillary I
in capillary II
in capillary III
Maximum permissable time measurement error
Number of single measurements required
Allowable deviations between measurements
The accuracy obtained with the AVS automated measuring system is greater since certain parameters
such as errors in reading, clock errors, etc. are eliminated.
Chosen so that the uncertainty inherent in the kinetic energy correction (HC) does not exceed the
1)
error allowed for time measurement.
13
[%]
[°C]
[°C]
[min]
[°]
[s]
[%]
[%]
[%]
± 1 ± 0.5 ± 0.1
± 0.1 ± 0.05 ± 0.01
± 0.05 ± 0.03 ± 0.005
15 15 15
4.5 3,3 1.5
250 350 650
100 135 240
100 100 100
± 0.33 ± 0.17 ± 0.03
4 4
± 1 ± 0.5 ± 0.1
4