Description; Preparation Of Sample; Selection Of Capillary; Cleaning The Viscometer - Schott Instruments 567 Mode D'emploi

1

Description

The viscometer basically consists of the capillary tube (1), venting tube (2) and the filling tube (3), the
capillary (7) with the measuring sphere (8), the pre-run sphere (9) (for Ubbelohde viscometers) and the
reference level vessel (5). Above and below the measuring sphere (8) are printed on timing marks M 1 and
M 2 . These marks not only define the flow-through volume of the sample, but also the mean hydrostatic
head (h). The capillary (7) ends in the upper part of the reference level vessel (5). The sample runs down
from the capillary (7) as a thin film on the inner surface of the reference level vessel (5) (suspended level
bulb).
The same correction seconds (kinetic energy correction. HC = Hagenbach-Couette correction) apply for
Ubbelohde viscometers of SCHOTT-GERÄTE with identical capillary diameters. No re-determination of
the kinetic energy correction (HC) is necessary if SCHOTT-GERÄTE viscometers of identical capillary
tube diameter are exchanged.
2

Preparation of sample

Low-viscosity samples should be passed through a SCHOTT glass filter (10 ... 100 µm) before measuring;
high-viscosity samples through a strainer of 0.3 mm mesh (test strainer 0.2; DIN 4188). Samples whose
setting point according to DIN 51 583 or pour point according to DIN 51 597 is not at least 30 °C below the
test temperature, must be heated up to 50 °C before measuring.
3

Selection of capillary

The diameter of the capillary should be selected so that the uncertainty inherent in the kinetic energy
correction (HC) does not exceed the error allowed for time measurement (see table). Therefore, for
precision measurements, efflux times whose correction seconds are stated in parentheses should not be
applied. A selection of a viscometer with a smaller capillary diameter is suggested.
4 Cleaning of viscometer
Before first use clean with 15 % H 2 O 2 and 15 % HCl. Thereafter rinse viscometer with a suitable solvent.
It must be completely dry and dust-free before it is put to use for either manual or automatic measuring.
In case of fully automatic program sequence with the V
rinsed with the successive sample where the number of rinsing operations can be selected.
5 Filling of viscometer
About 15 ml of the filtered sample, in case of Micro-Ubbelohde viscometers about 2.5 ml, are transferred
through the filling tube (3) into the reservoir (4). Filling capacity is indicated by filling marks on
reservoir (4).
6

Temperature conditioning of sample

After filling, hang viscometer with its stand (Ref. No. 053 92) into a glass-panelled thermal liquid/constant-
temperature bath of SCHOTT Instruments GmbH. To obtain the measuring accuracy of the viscometer,
the constant-temperature bath should maintain the set temperature at a constant ± 0.01 °C which is pos-
sible with SCHOTT Instruments GmbH constant temperature immersion circulators. Differences in
temperature of only 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 and, in case of Micro-Ubbelohde viscometers,
of approx. 5 minutes.
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S AVSPro, the viscometer is customarily
ISCO YSTEM