Apparatus and method for monitoring the presence of a conductive media

Patent · Mon Jan 01 04:00:00 EST 1979

OSTI ID:863408

DuVall, Bruce W ^[1]; Valentine, James W ^[1]; Morey, Kenneth O ^[1]

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1. Colorado Springs, CO

An inductive level sensor has inductively coupled primary and secondary windings. Circuitry drives the primary with an AC signal of constant current magnitude and selected frequency f to induce in the secondary, a voltage signal V of magnitude .vertline.V.vertline., frequency f and phase difference .phi. from the driving signal. Circuitry operates to generate a voltage output signal proportional to .vertline.V.vertline. cos (.phi.-.theta.), where .theta. is a selectively set phase shift factor. By properly and selectively adjusting the frequency f and phase shift factor .theta., an output signal .vertline.V.vertline. cos (.phi.-.theta.) can be provided which self-compensates for changes in mutual inductance caused by operating temperature variations so that an output signal is produced which is substantially linearly proportional to changes in the level of a pool of liquid metal being monitored. Disclosed also is calibration circuitry and circuitry for converting the voltage signal .vertline.V.vertline. cos (.phi.-.theta.) into a current signal.

• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4164146
• OSTI ID: 863408
• Country of Publication: United States
• Language: English

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