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US 4,138,639 AGranted
Fluid conductivity measurement
OwnerThomas B. Hutchinsinventor
Life of this patent
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Abstract
Fluid conductivity measuring apparatus employing fluid-coupled primary and secondary transformer windings where the primary transformer winding is energized by an oscillator. Accuracy in the apparatus is enhanced through the use therein of a feedback winding in the primary section of the transformer which couples with an output-level-control input in the oscillator to inhibit any tendency of the signal output level of the oscillator to change.
Claims2
Electrical apparatus with feedback stabilization for measuring the conductivity of a fluid comprising
- spaced primary and secondary transformer winding means,
- fluid conduit means, for containing a fluid whose conductivity is to be measured, electrically coupling said winding means,
- output-level-controllable oscillator means connected to energize said primary winding means and including an output-level-control input,
- feedback means operatively coupling said primary winding means and said input, operable, with said oscillator means oscillating, and in cooperation with said input and said primary means, to inhibit any tendency of the output level of the oscillator means to change, and
- signal output means operatively connected to said secondary winding means, constructed, with said apparatus functioning, to produce an output signal having an electrical characteristic which is directly relatable to the conductivity of any fluid contained in said fluid conduit means.
2 more elements
Dependencies are inferred from the claim text.