Viscosity is measured with various types of rheometers

Close temperature control of the fluid is essential to accurate measurements, particularly in materials like lubricants, whose viscosity can double with a change of only 5 degrees celcius.  For some fluids  it is a constant over a wide range of shear rates -Newtonian fluids.

Fluids that do no exhibit  a constant viscosity are name non-Newtonian fluids. Their viscosity cannot be described by a single number. Non-Newtonian fluids exhibit a variety of different correlations between shear stress and shear rate. One of the most common instruments for measuring kinematic viscosity is the glass capillary viscometer

In paint industries, viscosity is commonly measured with a Zahn cup, in which the efflux time is determined and given to customers. The efflux time can also be converted to kinematic viscosities (centistokes, cSt) through the conversion equations. Vibrating viscometers can also be used to measure viscosity. These models such as the Dynatrol use vibration rather than rotation to measure viscosity. Extensional viscosity can be measured with various rheometers that apply extensional stress. Volume viscosity can be measured with an acoustic rheometer.

RHEOTEK USA, Inc

Company Profile

RHEOTEK USA, Inc is based in Crestwood, Kentucky. The company's modern facilities include offices, laboratory and workshop. From this base, RHEOTEK provides marketing, distribution and service support of all RHEOTEK automated viscometer systems throughout North America and Mexico. The company is well located to support customers throughout the States, Canada and Mexico. An experienced network of RHEOTEK sales representatives are on hand to provide local support in your State. RHEOTEK'S highly trained and experienced engineers provide extensive service support on polymer and petroleum viscometer systems