Apparatus for detecting the center of a welded seam in accordance with fundamental harmonic component suppression
US4303883A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1979 |
| Grant date | Dec 1, 1981 |
| Priority date | — |
| Expiry date | Jul 12, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/2675
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus first magnitizes a base metal with an alternating flux to cross the welded seam of the base metal and the resulting leakage flux from the welded seam is detected by at least one flux search element to generate an AC signal. The fundamental harmonic component corresponding to the magnetizing signal used for the alternating magnetization is eliminated from the AC signal and the resulting signal voltage is sampled at a fixed period corresponding to the period of the magnetizing signal, thus detecting the center position of the welded seam from the result of the sampling. The apparatus comprises a magnetizing coil arranged adjacent to the base metal for the alternating magnetization thereof, at least one flux search element disposed adjacent to the base metal for leakage flux detecting purposes, means for eliminating from the detected AC output signal of the element the fundamental harmonic component corresponding to the magnetizing signal used for the alternating magnetization and a sampling circuit for sampling the output signal voltage of the eliminating means at a predetermined period, whereby the relative positional relation between the flux search element and the cen…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.