Kinematic viscometers
A kinematic "cup" viscometer
The kinematic viscometer in form of a cup is suitable only for relative measurements since the shear rate can be neither controlled nor monitored.
Besides, depending on the varying hydrostatic pressure during the emptying of the measuring cup the shear rate is also varying. For a non-Newtonian fluid this variation in shear rate will continuously change the apparent viscosity during the measurement.
Using a cup viscometer the test fluid is poured into the cup with the bottom outlet hole blocked. The hole is then uncovered and a stop-watch started. The time for emptying the cup is converted into a "viscosity" value using a conversion table coming with the instrument.
Due to limitating factors as described above the value is, however, only relative and cannot be used for e.g. design purposes when applied on non-Newtonian fluids.
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