The rheometer for measurements under pressure consists of a special constructed measuring cell equipped with a cylinder geometry:
Pressure range: Up to 500 bar, with special sealings up to 1000 bar
Temperature range: -
Rheometer: Haake M10, controlled by means of Rotovisco RV20 and Rheocontroller RC20
Volume: measuring cell 60 ml. For the filling under pressure usually a volume of 150 ml is needed.
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.
Schema of the pressure rheometer
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.
Schema for the filling of the pressure rheometer
With the depicted pressure generating devices, 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. Analogue to the Höppler viscometer a ball made from steel or glass runs through a tilted glass tube. The glass tube is located in a pressure resistant steel jacket pipe which allows viscosity measurements at pressures up to 2000 bar.
The temperature control is carried out by a thermostated bath.
Schema of the rolling ball viscometer