Detection of anomalies on railroad tracks
US6553838B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 27, 2001 |
| Grant date | Apr 29, 2003 |
| Priority date | — |
| Expiry date | Sep 12, 2021 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB61L2205/04
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates to a method and apparatus for detecting anomalies, defects or electromagnetic properties of electrically conductive and magnetically permeable materials by using a magnet to partially saturate the material, thereby lowering its permeability, and sending a second, higher frequency oscillating electromagnetic wave into the material. The oscillating magnetic flux field permeating into the electrically conductive material induces eddy waves. As the apparatus passes over the material, the properties of the induced eddy currents, and the corresponding magnetic flux field induced by such eddy currents, changes as the properties of the material change. These changes can be the result of defects or anomalies in the material or in connecting welds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.