Corrosion ratemeter
Abstract
Abstract A corrosion ratemeter with test speciment, reference and third electrodes contactable by a corrodant. A voltage loop circuit connects the reference and test electrodes in first and second arms of a balanced bridge to the inputs of a differential input amplifier and circuit common. The amplifier output connects to a signal correction means in "null" operation. Third and fourth bridge arms connect the inputs of the amplifier to circuit common of the D.C. source and one arm includes the signal correction means. A reference signal in one bridge arm controls the amplifier to pass current between the test and third electrodes for producing a polarization potential (e.g. 10 mv) between the test and reference electrodes. Readout means monitor the polarization current which is indicative of the corrosion rate occurring at the test electrode. The signal correction means balances the bridge during "null and measurement" operations relative to the freely corroding potential present at the test and reference electrodes whereby the ratemeter exhibits very high input impedance and high common mode rejection characteristics against extraneous electrical noise.
Inventors
- 👤 H Wilson
Bibliographic Details
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |