Technical information

Flow-through viscometer unit

he viscosity of fluids with precision of 1% can be measured by so called flow - through viscometers. The viscometers are equipped with temperature controlling jacket as can be seen on this figure.
The container 1 is filled with the liquid sample which is temperaturized on the constant selected temperature. The temeperaturizing liquid is flowing into the viscometer through the pipe 12. When the valve 2 is opened, the measured fluid flows into the space 5 to measure the time of flow between the points 9 and 10. There are installed two optical sensors in those positions. During the time measurement the liquid is flowing through the certified capillare 8. In the most cases is enough to clean the inner space of viscometer by the next sample. The result of cleaning "measurement" should not be taken into account. The next following measurement can be kept as correct in the precision range described above. The real cleaning by some solvent is also very simple and fast. In comparison with the classical Ubbelohde viscometer is the time for servicing and manipulation significantly reduced.

Ubbelohde Viscometers

Ubbelohde viscometers are used for viscosity measurements in the precision range of 0.05% - 0.1%. There is also used the jacket with temperaturizing liquid and two photosensors for the time measurement of the sample liquid flow through the measuring space. This figure shows the VISTEC's version of well known Ubbelohde viscometer with temperaturizing jacket. There is also available additional variant in viscometer design for gradient measurement with several measuring spaces and several pairs of photosensors (for possibility to extrapolate the measurement to the zero gradient).

Measurement Evaluation Unit and built-in Optional Ubbelohde Viscometer Control Unit

Measurement evaluation unit is electronical microprocessor controlled unit with following features and activities:

  • alphanumeric display for user checking and operations control

  • keyboard for measurement parameters user entry

  • control of photosensors and evaluation of liquid level signals in up to 5 viscometers or one gradient viscometer

  • evaluation of signals for control unit (lower unit on the picture)

  • internal matrix printer for the hardcopy of measurement conditions and results

  • outlet designed to establish the connecting with the standard personal computer (all measured data and conditions can be transferred to the PC for the following evaluation and respective storing)

  • possibility of remote control by the PC

  • The control unit consists of two air pressure generators V1, V2 and three air valves R1, R2, R3 depicted on this figure. The unit is designed also to control automatic dosing unit which is optional equipment for polymers measurement. The unit is connected to the measurement control unit with cable. There is possible to control the air pressure via turning the buttons.

    Whole System

    This picture shows the whole system with Measurement Evaluation Unit and optional Ubbelohde Viscometer Control Unit both remote controlled by PC.