Patent US4644313A successfully refreshed from Google Patents.
US4644313A
Expired / Lapsed
US
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Cylindrical magnet apparatus
Assignee: Hitachi Healthcare Manufacturing Ltd
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Filing: 1985-04-04
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Granted: 1987-02-17
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Expires: 2005-04-04
Abstract
Abstract A cylindrical permanent magnet apparatus and electromagnet apparatus used with a nuclear magnetic resonance imaging system are disclosed, in which a magnetic path of ferromagnetic material is arranged around a predetermined Z axis, magnetic field source are arranged at the ends of the magnetic path, a cylindrical magnetic flux conductor is interposed between the magnetic field sources, and an object to be inspected is adapted to be inserted in the cylindrical magnetic flux conductor. A cylindrical magnet apparatus comparatively light in weight which has a homogeneous magnetic field and has magnetic shielding effect and is suitable for routine applications is thus provided.
Inventors
- 👤 Goh Miyajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:52
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/381; G01R33/383; H; H01; H01F; H01F7/00; H01F7/02; H01F7/0273; H01F7/0278; H01F7/06; H01F7/20
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
57 words
A cylindrical magnet apparatus comprising a cylindrical magnetic yoke of a ferromagnetic material arranged around a predetermined axis (Z axis), magnetic field sources disposed at the ends of the cylindrical magnetic yoke, and a cylindrical magnetic flux guide interposed between said magnetic field sources, wherein an object to be inspected is inserted in said magnetic flux guide.
Claim 2
Dependent Claim
57 words
A cylindrical magnet apparatus comprising a cylindrical magnetic yoke of a ferromagnetic material arranged around a predetermined axis (Z axis), magnetic field sources disposed at the ends of the cylindrical magnetic yoke, and a cylindrical magnetic flux guide interposed between said magnetic field sources, wherein an object to be inspected is inserted in said magnetic flux guide.
Claim 3
Dependent Claim
33 words
A cylindrical magnet apparatus according to claim 1, wherein the cylindrical magnetic flux guide is made of one of iron, its alloy, ferrite for radio frequency and a molding material of ferromagnetic powder.
Claim 4
Dependent Claim
57 words
A cylindrical magnet apparatus according to claim 1, wherein and magnets making up the magnetic field sources are magnetized in the directions substantially perpendicular to the flow of the magnetic fluxes in the magnetic field generating space, the magnetic field sources of the magnets at the ends of the cylindrical magnetic yoke being magnetized in opposite directions.
Claim 5
Dependent Claim
70 words
A cylindrical magnet apparatus comprising a cylindrical magnetic yoke of ferromagnetic material arranged around a predetermined axis (Z axis), magnetic field sources made up of magnets at the ends of said cylindrical magnetic yoke, a cylindrical magnetic flux guide disposed between the magnetic field sources, and pole pieces provided at said magnetic field sources, wherein an object to be inspected is adapted to be inserted in said magnetic flux guide.
Claim 6
Dependent Claim
70 words
A cylindrical magnet apparatus comprising a cylindrical magnetic yoke of ferromagnetic material arranged around a predetermined axis (Z axis), magnetic field sources made up of magnets at the ends of said cylindrical magnetic yoke, a cylindrical magnetic flux guide disposed between the magnetic field sources, and pole pieces provided at said magnetic field sources, wherein an object to be inspected is adapted to be inserted in said magnetic flux guide.
Claim 7
Dependent Claim
30 words
A cylindrical magnet apparatus according to claim 4, wherein said pole pieces are cylindrical in shape, and the inner diameter thereof progressively increases toward the magnet center along Z axis.
Claim 8
Dependent Claim
35 words
A cylindrical magnet apparatus according to claim 5, wherein said pole pieces have outer ends thereof along Z axis which are tapered in such a manner that the inner diameter thereof is progressively increased outward.
Claim 9
Dependent Claim
86 words
A cylindrical permanent magnet apparatus comprising a cylindrical magnetic yoke made of ferromagnetic material, magnetic field sources made of permanent magnetic material in contact with the ends of the cylindrical magnetic yoke, a cylindrical magnetic field generating space passed through the ends and symmetric with respect to the central axis (Z axis) of the section of the cylindrical magnetic yoke, and a cylindrical flux guide of a ferromagnetic material disposed in said cylindrical space, wherein a homogeneous magnetic field is formed inside said magnetic flux guide.
Claim 10
Dependent Claim
86 words
A cylindrical permanent magnet apparatus comprising a cylindrical magnetic yoke made of ferromagnetic material, magnetic field sources made of permanent magnetic material in contact with the ends of the cylindrical magnetic yoke, a cylindrical magnetic field generating space passed through the ends and symmetric with respect to the central axis (Z axis) of the section of the cylindrical magnetic yoke, and a cylindrical flux guide of a ferromagnetic material disposed in said cylindrical space, wherein a homogeneous magnetic field is formed inside said magnetic flux guide.
Claim 11
Dependent Claim
56 words
A cylindrical permanent magnet apparatus according to claim 7, wherein said magnetic field sources of permanent magnet material, are magnetized in the direction parallel with the flow of the magnetic fluxes in the magnetic field generating space, and the magnetic field sources at the ends of the cylindrical magnetic yoke are magnetized in the same direction.
Claim 12
Dependent Claim
66 words
A cylindrical permanent magnet apparatus according to claim 7, wherein those sides of the magnetic field sources which are opposite to the sides thereof in contact with the pole pieces respectively are in contact with the annular magnetic yoke of ferromagnetic material, and the magnetic field sources are disposed in a closed magnetic loop not in direct contact with the surroundings of the magnetic field sources.
Claim 13
Dependent Claim
90 words
A cylindrical electromagnet apparatus comprising a cylindrical magnetic yoke made of ferromagnetic material, magnetic flux sources made of coils energized at the ends of the cylindrical magnetic yoke, a cylindrical magnetic field generating space passed through the ends symmetric with respect to the center of the central axis (Z axis) of the section of the cylindrical magnetic yoke, and a cylindrical magnetic flux guide made of ferromagnetic material within said cylindrical magnetic field generating space, wherein a homogeneous magnetic field of uniform intensity is formed inside the magnetic flux guide.
Claim 14
Dependent Claim
90 words
A cylindrical electromagnet apparatus comprising a cylindrical magnetic yoke made of ferromagnetic material, magnetic flux sources made of coils energized at the ends of the cylindrical magnetic yoke, a cylindrical magnetic field generating space passed through the ends symmetric with respect to the center of the central axis (Z axis) of the section of the cylindrical magnetic yoke, and a cylindrical magnetic flux guide made of ferromagnetic material within said cylindrical magnetic field generating space, wherein a homogeneous magnetic field of uniform intensity is formed inside the magnetic flux guide.
Claim 15
Dependent Claim
28 words
A cylindrical electromagnetic apparatus according to claim 10, further comprising cylindrical pole pieces made of ferromagnetic material disposed inside the coils energized for uniforming the magnetic fluxes generated.
Claim 16
Dependent Claim
32 words
A cylindrical electromagnetic apparatus according to claim 11, which further comprises annular yoke supported by the cylindrical yoke, said pole pieces making up a magnetic circuit in contact with the annular yoke.
Claim 17
Dependent Claim
28 words
A cylindrical electromagnet apparatus according to claim 10, wherein coils are wound around the ferromagnetic poles and current is supplied in said coils thereby to generate magnetic fluxes.
Claim 18
Dependent Claim
36 words
A cylindrical magnet apparatus according to claim 1, wherein the magnetic field sources are disposed only adjacent to end portions of the cylindrical magnetic flux guide, the cylindrical magnetic flux guide being a non-permanent magnet member.
Claim 19
Dependent Claim
36 words
A cylindrical magnet apparatus according to claim 4, wherein the magnetic field sources are disposed only adjacent to end portions of the cylindrical magnetic flux guide, the cylindrical magnetic flux guide being a non-permanent magnet member.
Claim 20
Dependent Claim
36 words
A cylindrical magnet apparatus according to claim 7, wherein the magnetic field sources are disposed onlu adjacent to end portions of the cylindrical magnetic flux guide, the cylindrical magnetic flux guide being a non-permanent magnet member.
Claim 21
Dependent Claim
36 words
A cylindrical electromagnetic apparatus according to claim 10, wherein the magnetic flux sources are disposed only adjacent to end portions of the cylindrical magnetic flux guide, the cylindrical magnetic flux guide being a non-permanent magnet member.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-16 | 1990-08-18 | 1991-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-16 | 1994-08-18 | 1995-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-16 | 1998-08-18 | 1999-02-17 | $7700.00 | Window Closed / Lapsed |