Eddy current probe method and device for simultaneously measuring the distance between metal tubes and oxide thickness on the tubes
US5124641A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 27, 1990 |
| Grant date | Jun 23, 1992 |
| Priority date | — |
| Expiry date | Dec 27, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The distance between substantially parallel metal tubes forming a flat sheet and the thicknesses of oxide layers covering the tubes are simultaneously measured. The tubes may particularly be sheaths of a nuclear fuel assembly. The method includes the step of moving an eddy current probe parallel to the sheet while maintaining said probe applied onto the successive tubes of the sheet; recording an electric signal delivered by the probe and representing impedance variations of said probe responsive to displacement of said probe; computing the distances between successive ones of said rods from measurement of the amounts of displacement of said probe between the extremum values of said electric signal which correspond to successive extrema of said impedance; and deriving the thickness of the oxide layers on successive ones of said tubes from successive comparisons between the value of the respective extremum and values obtained by measurement of the impedance value on standard tubes carrying predetermined known thickneses of said oxide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.