Measuring Equipment » Viscosity Measuring Systems PVS

Configurations

PVS application examples

Thanks to its modular design, the LAUDA PVS always provides you with a tailor-made system for the right method.

Determination of the solution viscosity of plastics

Single-point methods

The following methods can be carried out very quickly with any of the PVS configurations:

Point-slope method
Schulz-Blaschke method
Huggins method
Billmeyer method

Parallel linear regression

The fastest method of carrying out linear regression. The different required sample concentrations are measured simultaneously at three to six measuring points in independently operating measuring stands. A measurement, including cleaning, takes approx. 25 minutes.

Serial linear regression

This method can be carried out with only one measuring stand. The sample is diluted successively in the viscometer between individual measurements by addition of a solvent with an automatic burette. After each change in concentration a magnetic stirrer accelerates thermostating and homogenisation of the sample. This not only simplifies the work, but also provides for high-precision dosing for excellent reproducibility of the concentration sequences.

Measuring system for polyolefins

This system allows simple and reliable measurement of the viscosity of polyethylene and polypropylene sulfide solutions at temperatures up to 160°C. Even the measurement of dissolved polyphenyl sulfide at temperatures over 200°C is manageable. The samples are placed as granulate or powder directly into the dilution viscometer and are dissolved there, whereby the solvent for this and for additional dilution steps is added precisely with a burette. Manual movement of hot samples or solvents, as is otherwise required, is thus eliminated.

Measuring of technical lubricants

Viscosity index

Primarily in the petroleum industry, repeated measurements are taken to determine and control the viscosity and its change at different temperatures. The software module VID-DLL computes the viscosity index very efficiently. With a thermostat, the necessary measurements are taken at 40°C and 100°C after temperature change. This can be done especially quickly using measuring stands in two thermostats, since measurements at 40°C and 100°C occur almost simultaneously here. With eight measuring stands and four thermostats, the viscosity values can be conveniently determined in a single measuring operation across a large temperature range, for example -20, 20, 40 and 100°C.

Low temperature viscosity

With the PVS Processor viscosity measuring system, viscosity of fuels can be determined under realistic conditions of use down to -60°C. For the first time, this is also possible down to -20°C with automatic cleaning. In addition to powerful LAUDA chillers, a cold trap for air drying is also used for this process.

Determination of enzyme activity

Solutions of certain biological macromolecules change their viscosity under the influence of enzymes, when these more or less cut the contained molecule chains. In these cases, enzyme activities can be very precisely determined from the time-independence of the relative viscosity during the enzyme reaction.

In addition to the control of the measuring sequence, the software module ENZ-DLL automatically calculates and outputs the enzyme activity, in particular, for the enzymes hyaluronidase and cellulose from the comparison with reference measurements - in accordance with international pharmaceutical standards. The module also allows the graphic representation of the logarithmic relative viscosity over the reaction time, plots the regression line through the measuring points, and determines the half-life value of the reaction. With up to 99 individual measurements, the module records the changes across a wide time range. Depending on the equipment, up to eight measurements can be carried out simultaneously.