Periodic magnet unidirectional transducer
AssigneeRockwell International Corporation
InventorCarmine F. Vasile
Life of this patent
Estimating the term…
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.
Claims10
A periodic magnet, unidirectional transducer comprising:
- a first row of permanent magnets, the N-S axes of said magnets being substantially parallel, adjacent magnets in said first row having differently oriented polarity so that a first periodic magnetic field is created;
- a second row of permanent magnets, the N-S axes of said magnets being substantially parallel, adjacent magnets in said first row having differently oriented polarity so that a second periodic magnetic field of the same periodicity as said first field is created, said second row being positioned adjacent and parallel to said first row and being offset along its length by one-quarter period from said second row;
- and
- separate coils around said first and said second rows of magnets.
A periodic magnet, unidirectional transducer comprising:
- a first set of a "n" number of rows of permenent magnets, the N-S axes of said magnets being substantially parallel, adjacent magnets in each of said rows having differently oriented polarity so that each row of magnets creates a periodic magnetic field of the same periodicity and polarity, said rows being adjacent and parallel in side-by-side relation, each row being offset from its adjacent row by "1/2n" th period;
- a second set of a "n" number of rows of permenent magnets, said second set being substantially the same as said first set, said second set being positioned adjacent and parallel tp said first set in side-by-side relation and offset from said first set by "1/2n" th period;
- and
- a separate coil wrapped around each of said rows of permenent magnets in each of said sets.
Dependencies are inferred from the claim text.