ELECTRONIC (DRIVEN) VISCOMETERS
Brookfield viscometers employ the well-known principle of rotational viscometry; they measure viscosity by sensing the torque required to rotate a spindle at constant speed while immersed in the sample fluid. The torque is proportional to the viscous drag on the immersed spindle, and thus to the viscosity of the fluid. For the user, rotational viscometry has several advantages:
The continuous rotation of the spindle allows uninterrupted measurements to be made over long periods of time-dependent fluid properties.
The rate of shear the sample fluid is subjected to is constant, so the instrument is suitable for measuring Newtonian and non-Newtonian fluids.
By rotating the spindle at several different speeds, shear-dependent behaviour of non-Newtonian fluids can be detected and analysed.