3712117 is referenced by 32 patents and cites 4 patents.

A viscosity measuring system especially useful in pollution and chemical process control applications. A variable gain amplifier drives a magnetic coil which causes a torsion member to oscillate. The amplitude of the oscillations is sensed by a transducer, and converted to a DC voltage by an amplitude monitoring circuit. The DC voltage, which represents the instantaneous amplitude of mechanical oscillation, is compared to a reference DC voltage which represents the desired amplitude of oscillation. The resulting error signal is utilized to control the gain of the amplifier in such a manner that the amplitude of mechanical oscillation is maintained constant and equal to the desired amplitude. The viscosity of the fluid in which the torsion member is immersed is obtained by providing an output signal which is a measure of the power provided by the amplifier to the magnetic coil in order to maintain the desired constant amplitude of oscillation. Preferably, the output signal is obtained from the voltage developed across a resistor in series with the magnetic coil.

Title
High precision wide dynamic range viscous loss measuring apparatus
Application Number
05/105,833
Publication Number
3712117
Application Date
January 12, 1971
Publication Date
January 23, 1973
Inventor
Oppliger Hans R
Matusik Frank J
Fitzgerald J Vincent
Assignee
National Metal and Refining Company
IPC
G01n 11/16
G01N 11/10
G01N 11/16
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