US3720870A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for determining the permeability of a non-magnetic medium
Assignee: Individual
•
Filing: 1971-07-19
•
Granted: 1973-03-13
•
Expires: 1991-07-19
Abstract
Abstract A plurality of non-ferromagnetic bodies having a poor conductivity and different magnetic permeabilities are positioned in a gap formed in a magnetic circuit biased by a DC magnetic flux. The bodies are displaced relatively within the gap to cause a change of the flux, thereby providing alternate outputs in the coil. These alternate outputs are proportional to the difference between the magnetic permeabilities of these bodies. If one body is a sample of known permeability and the other body is sample of unknown permeability to be measured, the unknown permeability of the sample to be measured may be determined instantaneously by suitably processing or evaluating the alternate output or outputs.
Inventors
- 👤 O Sueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:36
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/12; G01R33/1223; G01N; G01N27/00; G01N27/72; G01N27/74
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
185 words
An apparatus for determing the permeability of a non-magnetic medium, comprising: a magnetic circuit having a constant magnetic bias, said magnetic circuit having a gap, detecting coil means electrically coupled to said magnetic circuit, a magnetic flux permeable medium positioned in said gap, said medium having a first region of a first material of unknown permeability, and second and third regions of second and third materials respectively of known different permeabilities, means for displacing said medium in said gap for changing the magnetic flux in said magnetic circuit as a function of the displacement of said regions, whereby a first output signal is produced in said coil means in response to a change of displacement of said first and second regions with respect to said magnetic circuit, and a second output signal is produced in said coil means in response to a change of displacement of said second and third regions with respect to said magnetic circuit, and output circuit means connected to said coil means and responsive to said first and second signals for determining the permeability of said material of said first region.
Claim 2
Independent Claim
185 words
An apparatus for determing the permeability of a non-magnetic medium, comprising: a magnetic circuit having a constant magnetic bias, said magnetic circuit having a gap, detecting coil means electrically coupled to said magnetic circuit, a magnetic flux permeable medium positioned in said gap, said medium having a first region of a first material of unknown permeability, and second and third regions of second and third materials respectively of known different permeabilities, means for displacing said medium in said gap for changing the magnetic flux in said magnetic circuit as a function of the displacement of said regions, whereby a first output signal is produced in said coil means in response to a change of displacement of said first and second regions with respect to said magnetic circuit, and a second output signal is produced in said coil means in response to a change of displacement of said second and third regions with respect to said magnetic circuit, and output circuit means connected to said coil means and responsive to said first and second signals for determining the permeability of said material of said first region.
Claim 3
Independent Claim
185 words
An apparatus for determing the permeability of a non-magnetic medium, comprising: a magnetic circuit having a constant magnetic bias, said magnetic circuit having a gap, detecting coil means electrically coupled to said magnetic circuit, a magnetic flux permeable medium positioned in said gap, said medium having a first region of a first material of unknown permeability, and second and third regions of second and third materials respectively of known different permeabilities, means for displacing said medium in said gap for changing the magnetic flux in said magnetic circuit as a function of the displacement of said regions, whereby a first output signal is produced in said coil means in response to a change of displacement of said first and second regions with respect to said magnetic circuit, and a second output signal is produced in said coil means in response to a change of displacement of said second and third regions with respect to said magnetic circuit, and output circuit means connected to said coil means and responsive to said first and second signals for determining the permeability of said material of said first region.
Claim 4
Independent Claim
185 words
An apparatus for determing the permeability of a non-magnetic medium, comprising: a magnetic circuit having a constant magnetic bias, said magnetic circuit having a gap, detecting coil means electrically coupled to said magnetic circuit, a magnetic flux permeable medium positioned in said gap, said medium having a first region of a first material of unknown permeability, and second and third regions of second and third materials respectively of known different permeabilities, means for displacing said medium in said gap for changing the magnetic flux in said magnetic circuit as a function of the displacement of said regions, whereby a first output signal is produced in said coil means in response to a change of displacement of said first and second regions with respect to said magnetic circuit, and a second output signal is produced in said coil means in response to a change of displacement of said second and third regions with respect to said magnetic circuit, and output circuit means connected to said coil means and responsive to said first and second signals for determining the permeability of said material of said first region.
Claim 5
Dependent Claim
18 words
The apparatus of claim 1, wherein said means for displacing said medium comprises means for rotating said medium.
Claim 6
Dependent Claim
15 words
The apparatus of claim 1, wherein the material of said first region is a fluid.
Claim 7
Dependent Claim
11 words
The apparatus of claim 3, wherein said fluid is a gas.
Claim 8
Dependent Claim
10 words
The apparatus of claim 4, wherein said gas is oxygen.
Claim 9
Dependent Claim
23 words
The apparatus of claim 3, wherein said first region comprises a space which includes said gap, said space being filled with said fluid.
Claim 10
Dependent Claim
39 words
The apparatus of claim 2, wherein said magnetic circuit comprises a plurality of magnetic pole pairs arranged to form said gap, whereby a plurality of gap portions are formed, said medium comprising a corresponding plurality of groups of regions.
Claim 11
Dependent Claim
86 words
The apparatus of claim 7, wherein said first material is a fluid and said gap is circular, said apparatus further comprising housing means defining a space surrounding said gap, said means for rotating said medium comprising rotating shaft means extending normally through the center of said circular gap, wherein said pole pairs are arranged about the periphery of said circular gap, and further comprising tube means for introducing said fluid to said housing, said tube means being positioned coaxially with respect to said rotating shaft means.
Claim 12
Dependent Claim
56 words
The apparatus of claim 8, wherein said magnetic circuit comprises a cylindrical permanent magnet having a central longitudinally extending aperture and a disc shaped pole piece at each end of said cylindrical magnet, said pole pairs extending centrally in said aperture between said pole pieces, said housing and coil means being positioned within said cylindrical magnet.
Claim 13
Dependent Claim
89 words
The apparatus of claim 7, wherein said magnetic circuit comprises a columnar magnetic pole piece and a cylindrical magnetic pole piece positioned concentrically about the columnar magnetic pole piece, whereby said gap is formed therebetween, said pole pairs comprising a plurality of magnetic pole pieces positioned to extend axially along the outer circumference of the columnar magnetic pole piece and the inner circumference of the cylindrical magnetic pole piece, whereby said gap portions are formed therebetween, said medium having a corresponding plurality of groups of regions also extending circumferentially.
Claim 14
Dependent Claim
141 words
The apparatus of claim 1, wherein said magnetic circuit comprises a columnar magnetic pole piece having an outer circumferential wall, and a cylindrical magnetic pole piece having an inner circumferential wall, said first material being a fluid, said medium having a cylindrical shape with said second and third regions forming a partition for the fluid to divide the gap into an inner space defined by the partition and the outer circumferential wall of the columnar magnetic pole piece, and an outer space defined by the partition and the inner circumferential wall of the cylindrical magnetic pole piece, and further comprising means for introducing said fluid into the inner space at one axial end thereof, means for discharging fluid from the corresponding end of the outer space, and fluid flow path means between the other ends of the inner and outer spaces.
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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |