Group Discussion View

Can Micro Motion devices accurately measure the viscosity of non-Newtonian liquids?

Jim,
MMI viscosity analyzers use vibrating fork technology. As such the vibrating fork does not have a defined shear rate because the movement at the end of the tines is greater that that at the base. With other technologies such as rotating discs one can calculate the shear rate in reciprocal seconds.

Since non-Newtonian fluids are shear sensitive it is critical to report the shear rate as well as the observed viscosity and temperature. Our fork viscometers could therfore give a viscosity indication of a non-Newtonian fluid but it would not, in my view, be very useful without a known shear rate.

For this reason our fork viscosity sensors are focused mainly on hydrocarbon products which are for the most part Newtonian fluids.

Jim,

In addition to Albert's comments, the shear rate of vibrating element meters such as the MMI fork technology are affected by not just viscosity but density and temperature as well, so the best that can be expected from measuring non-Newtonian liquids is one of a repeatable measurement when operating under constant repeatable line conditions.