Periodic magnet unidirectional transducer
US4232557A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 23, 1979 |
| Grant date | Nov 11, 1980 |
| Priority date | — |
| Expiry date | Apr 23, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/0425
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electromagnetic transducer is provided which transmits and receives ultrasonic waves from a metallic part predominately in only one direction. At least two rows of permanent magnets are placed adjacent each other in a side-by-side relation. The N-S axes of the magnets are substantially parallel and adjacent magnets in each row have opposite polarity so that two periodic magnetic fields are created. The adjacent magnets are off-set by one-fourth period. Coils wrapped around each row of magnets are driven in phase quadrature in order to generate a unidirectional elastic wave in the metallic part. In another embodiment, sets of three rows of magnets are offset by one-sixth period and driven in 60.degree. phase shift.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.