The idea is as simple as it is ingenious:

The transmitter drives the sensor probe to an oscillating torsion at its resonance frequency with a very small amplitude. When the probe is immersed in a liquid, it “rubs” against the adjacent fluid layer. This creates a damping effect due to its viscosity.

And now comes the difference to comparable systems: using a fast PID controller, the transmitter compensates for the amplitude loss caused by this damping effect, i.e. it keeps the amplitude constant despite the changing viscosity. This changes the driving voltage, which is the basis of the viscosity value. Using this technique, the ViscoScope® viscometer measures the dynamic viscosity x density in mPa·s x g/cm³ (η x ρ), responds to changes in viscosity in less than 2 seconds and enables the detection of the smallest differences – even under challenging process conditions.

Because it is driven at a low amplitude at its resonant frequency, the probe is not subject to material fatigue. You will not find any moving parts, joints or seals in our probe because all parts that come into contact with the process are welded. The result: an extremely durable, reliable and maintenance-free process viscometer.