04920787 is referenced by 24 patents and cites 17 patents.

A resonator in the form of a cylindrical body is immersed in a fluid to be measured and excited by a piezoelectric transducer in the vicinity of its natural frequency. The vibration frequency is stabilized by a feedback loop. In that feedback loop a phase shift is introduced which can be switched between to discrete values. The resulting difference in frequency of oscillation of the resonator is proportional to the damping ratio of the resonator and is, therefore, a measure for the viscosity of the fluid. The natural frequency of the piezoelectric transducer is substantially higher than the natural frequency of the resonator, and the oscillation of the resonator is mechanically isolated from the housing by an inertial mass - spring arrangement with low natural frequency.

Title
Viscometer
Application Number
7/197990
Publication Number
4920787
Application Date
May 24, 1988
Publication Date
May 1, 1990
Inventor
Joseph Goodbread
Grossmannstrasse 34, Zurich
CH
Mahir Sayir
Im Straler 7, Zurich
CH
Jurg Dual
Bergstrasse 5, Zurich
CH
Agent
Powell L Sprunger
IPC
G01N 11/16
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