Rheometers

Rheometers determine the viscosity and viscoelastic properties of solids, semisolids, and fluids. Rheometers dealing with shear stress are known as shear rheometers and those applying extensional stress are called extensional rheometers. They are available in a variety of designs: Cone-and-plate, coaxial cylinder, capillary, rectangular torsion, bending and compression, and parallel disk.

Rheometers utilize techniques such as rotary clamp stretching, capillary breakup, opposing jets, stagnation point flow and filament stretching (by academic institutions) to measure extensional viscosity. Rheometers are used in the chemical, petrochemical, cosmetics, pharmaceutical, construction, and food industries for material characterization, to ensure quality, to explain the phenomena of physical processing, and to generate data for designing the equipment used for processing.