05054313 is referenced by 51 patents and cites 2 patents.

Electronic control circuitry for obtaining precise inline process control data as to viscosity of fluids over a wide viscosity range, with high tolerance of ambient noise and vibration. An electromechanical transducer with an oscillating sensor is immersed in a flowing liquid, with the power required to sustain predetermined oscillation parameters being a measure of viscosity-density product. The gain of a variable gain amplifier which provides positive feedback to sustain oscillation is controlled in response to the integrated error signal output of a comparator which compares a DC value corresponding to the RMS amplitude of mechanical oscillation with a DC reference value. The monitoring of RMS amplitude rather than peak amplitude (as is done by a phase-sensitive sample-and-hold arrangement in the prior art), coupled integration of the error signal, results in a great improvement in immunity to ambient noise and vibration. Other features includes automatic calibration and temperature compensation whereby viscosity at a desired temperature can be determined even though the measurement is made at different temperature.

Title
Control circuitry for viscosity sensors
Application Number
7/554285
Publication Number
5054313
Application Date
July 17, 1990
Publication Date
October 8, 1991
Inventor
John Batton
New York
NY, US
Edmond Dougherty
Strafford
PA, US
John Stone
Vincentown
NJ, US
Frank J Matusik
Piscataway
NJ, US
Teresa M Walsh
Lawrenceville
NJ, US
John V Fitzgerald
Metuchen
NJ, US
Agent
Arthur L Lessler
Assignee
National Metal and Refining Company
NJ, US
IPC
G01N 11/14
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