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Pressure
rheology
The rheometer for measurements under pressure
consists of a special constructed measuring cell equipped with
a cylinder geometry:
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Pressure range: Up to 500 bar, with special sealings up to
1000 bar |
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Temperature
range: -50…150 °C |
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Rheometer:
Haake M10, controlled by means of Rotovisco RV20 and Rheocontroller
RC20. |
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Cylinder-geometry:
length of rotor 58,0 mm, diameter of rotor Ri 35,0 mm, diameter
of stator Ra 35,9 mm. the ratio Ra/Ri = 1,0257 satisfy ISO
3219 and DIN 53019 for concentrically cylinder geometries. |
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Volume:
measuring cell 60 ml.
For the filling under pressure usually a volume of 150 mL
is needed. |
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The
cylinder geometry is located inside a cell that is suitable
to perform measurements under pressure. The cell is surrounded
by a heating jacked in order to guarantee constant temperature.
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Schema
of the pressure rheometer
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Despite
the rheometer pressure cell itself we possess a large amount
of accessories for measurements under pressure. Thus the rheometer
cell can charged from a second pressure cell that is separated
by means of a movable piston into two compartments. One side
contains the sample while the other one is filled with hydraulic
oil in order to establish the desired pressure. With this setup
it is for example possible to perform measurements in fluid
or supercritical gases (e.g. propane or CO2). A schema
of the setup is shown in the following figure.
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Schema
for the filling of the pressure rheometer.
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With the depicted pressure generating devicec,
pressure sensors and sufficiend valves it is possible to perform
rheological measurements of reactions in supercritical gases.
Rolling
ball viscometer
In addition
to the rotational rheometer we posses a rolling ball viscometer.
Alternativ zum Rotationsrheometer steht auch ein Kugelrollviskosimeter
zur Verfügung, in dem - ähnlich wie bei einem Höppler-Viskosimeter
- eine Stahl- oder Glaskugel in einem geneigten Glasrohr läuft.
Im Unterschied zu einem normalen Höppler-Viskosimeter befindet
sich das Glasrohr jedoch in einer druckfesten Stahlzelle, die
Messungen bei Drücken bis zu 2000 bar erlaubt.
Zur Temperierung wird das Kugelrollviskosimeter in ein thermostatisiertes
Wasserbad eingetaucht.
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Schema
of the rolling ball viscometer.
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