Seatons
Seatons

Viscosity

Kinematic: A sample is placed in a "U" tube viscometer and the time taken for it to flow through the viscometer is noted. This is then converted to the viscosity.

Absolute: The time taken for a sphere of known dimensions to fall a known distance through the oil can be converted to the viscosity. Many other methods are also available, eg Redwood, flow cups, Churchill, cone & plate, Brookfield.

 

Method used Kinematic: BS 188
Absolute: BS 188
Units Kinematic: Stokes
1 stoke = 1 x 10-4 m2/s

Absolute: Poise
1 poise = 0.1 PaS
Significance of result
Oil viscosity is important to varnish, ink and paint formulators.
Notes In general kinematic viscosity is determined for low viscosity oils, whilst absolute viscosity is used for higher ones. Viscosities are usually carried out at 25°C but may be performed at other temperatures.

The test temperature and method must be quoted.

Viscosity decreases with increasing temperature.

Flask