Method and apparatus for estimating the condition of a coating on an underground pipeline
US7880484B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 2008 |
| Grant date | Feb 1, 2011 |
| Priority date | — |
| Expiry date | Sep 19, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N17/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods are provided for reducing interference from stray currents in buried pipelines/metal structures during MEIS testing or other current-sensing applications in the pipeline. Methods are also provided for measuring bulk complex electrical impedance between a buried pipe and the soil, thereby rendering an indication of the quality of the anti-corrosive coating. Methods are also provided for measuring the complex propagation constant of AC voltages propagating along an attenuative pipeline. This information is useful for assessing the general condition of the anti-corrosive coating involved, or to enhance MEIS inspection of the pipeline. Methods are also provided for enhancements to MEIS testing, including (a) canceling magnetometer offset effects associated with the Earth's magnetic field after the magnetometer is positioned for measurement, (b) implementing a separate sensing connection to the pipe so as to avoid interference from voltage loss in the pipe feed-line connection, (c) providing a power amplifier to excite the pipe with large-amplitude signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.