Transient electromagnetic method for detecting irregularities on conductive containers
US4929898A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1988 |
| Grant date | May 29, 1990 |
| Priority date | — |
| Expiry date | Dec 29, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N17/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A transient electromagnetic method for detecting irregularities on container walls by measuring wall thickness. The method utilizes a transmitting antenna and a separate receiving antenna arranged in a loop-loop configuration. The transmitting antenna induces current into the container wall and the receiving antenna and the receiver detect the decay of the induced current, which is then analyzed to detect wall thickness. A receiving antenna array of many receiving antennas is used to increase the spatial resolution. Simultaneous measurement of the induced current by the receiving antennas reduces noise that is coherent across the array. Use of a noise antenna located so as to be unaffected by the transmitting antenna further reduces noise. The received signal from the receiving antenna array is displayed on a two-dimensional display in a spatial arrangement that corresponds to the spatial arrangement of the receiving antennas. The display can be scrolled over the time range of the received signals to produce a moving image, so that irregular areas can be more easily detected than with a static display.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.