Application
The Thermo Scientific HAAKE Viscotester® 550 is specially designed for Quality Control applications. It is a rotational viscometer that measures precisely, quickly and simply the viscosity and flow behaviour of liquid and semisolid test materials. All results like viscosity, shear stress, shear rate, yield point and operating temperature are displayed in the digital LED display.
The HAAKE Viscotester® 550 does not mind if a sample is thin like an oil, a paint or a ceramic slurry or as pasty as cremes, salves or a PVC plastisol. One unit covers the whole application range from very thin to very thick. Even more demanding tasks will be fulfilled.
For example, the automatic characterization of the flow behaviour of non-Newtonian fluids or the determination of the yield point using the CD-principle (= Controlled Deformation) can be done. Any one out of a set of 10 predefined routines will be executed with precision and repeatability. Also all predefined routines and the results obtained with them will be documented using a printer.

Measuring Principle
By its design, the HAAKE Viscotester® 550 is a Searle viscometer. A rotational speed is preset and the flow resistance of the sample is measured or in other words the torque required to maintain the set speed is proportional to the viscosity. From the torque required, the set speed and the geometry factors of the applied sensor, all final information on the viscosity, shear stress and the shear rate is calculated.
The results are displayed digitally and can be printed simultaneously. For viscosity measurements a total  of 60 different rotational speed steps are available. 50 out of these 60 are factory set, the remaining 10 are userprogammable. The 60 steps cover a wide range reaching from 0.5 rpm to 800 rpm. The resulting torque is measured via a non-contact, low displacement sensor which enables the extended measuring range with perfect signal linearity over the whole range. The operating temperature can be measured by Pt100 probes located either in the sensor used or directly in the test material.