Evaluation of the metrological performance of two kinds of rotational viscometers by means of viscosity reference materials

Rotational viscometers are widely used in the industry and in research laboratories. In order to evaluate the metrological performance of these instruments, viscosity measurements of Newtonian reference materials were carried out with a rotational viscometer of the Brookfield type and with a rheometer. Their results were compared with viscosity reference values, which were obtained in this study by measuring the same reference materials with kinematic viscosity and density working standards. Results show that the rheometer yielded more exact viscosity values than the Brookfield type rotational viscometer for low dynamic viscosities. At higher viscosities, both viscometers demonstrated to have similar metrological behaviors.