Patent US3922599A successfully refreshed from Google Patents.
US3922599A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A.C. electromagnetic thickness gauge utilizing premagnetization of the gauge core to render sensitivity independent of thickness
Assignee: Elektro-Physik Hans Nix & Dr -Ing E Steingroever Kg
•
Filing: 1974-08-28
•
Granted: 1975-11-25
•
Expires: 1994-08-28
Abstract
Abstract The sensitivity of an electromagnetic thickness gauge of the type which employs a pole piece to contact the surface being measured, can be altered to provide more accurate readings of very thin coatings by premagnetizing the core. Premagnetization can be accomplished by using a permanent magnet, or an energized coil.
Inventors
- 👤 Erich Steingroever
- 👤 Hans F Nix
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:58
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/10; G01B7/105
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
164 words
In electromagnetic thickness gauges for measuring the thickness of a layer applied to a base wherein the applied layer and the base are composed of two dissimilar materials one of sid two materiaLs having a composition which influences a magnetic field, such as ferromagnetic and electrically conductive materials, and the gauge includes a core of soft magnetic material having a single pole piece for contact with the exposed surface of the layer to be measured and being provided with means for inducing electrical values in a measuring coil associated with said core by subjecting the core to an alternating magnetic field, the electrical values induced in the measuring coil being a function of the strength of the magnetic field and the thickness of the layer being measured, the improvement which comprises means for adjustably pre-magnetizing said soft magnetic core by subjecting the core to an additional uni-directional magnetic field to alter the sensitivity of the gauge to predetermined values of thickness to be measured.
Claim 2
Dependent Claim
164 words
In electromagnetic thickness gauges for measuring the thickness of a layer applied to a base wherein the applied layer and the base are composed of two dissimilar materials one of sid two materiaLs having a composition which influences a magnetic field, such as ferromagnetic and electrically conductive materials, and the gauge includes a core of soft magnetic material having a single pole piece for contact with the exposed surface of the layer to be measured and being provided with means for inducing electrical values in a measuring coil associated with said core by subjecting the core to an alternating magnetic field, the electrical values induced in the measuring coil being a function of the strength of the magnetic field and the thickness of the layer being measured, the improvement which comprises means for adjustably pre-magnetizing said soft magnetic core by subjecting the core to an additional uni-directional magnetic field to alter the sensitivity of the gauge to predetermined values of thickness to be measured.
Claim 3
Dependent Claim
25 words
The invention defined in claim 1, wherein said means for adjustably pre-magnetizing comprises a permanent magnet mounted in the vicinity of said soft magnetic core.
Claim 4
Dependent Claim
20 words
The invention defined in claim 2, wherein said permanent magnet pre-magnetizing means is mounted for movement relative to said core.
Claim 5
Dependent Claim
31 words
The invention defined in claim 1, wherein said means for adjustably pre-magnetizing comprises a coil mounted in the magnetic field of said core and means for energizing said last mentioned coil.
Claim 6
Dependent Claim
39 words
The invention defined in claim 1, wherein said pre-magnetizing means is adjusted to decrease the sensitivity of said gauge to a thin layer of material being measured as compared to the sensitivity of the gauge without said pre-magnetizing means.
Claim 7
Dependent Claim
37 words
The invention defined in claim 5, wherein said pole piece comprises one end of an elongated core and said pre-magnetizing means comprises a permanent magnet mounted in the magnetic field at the other end of said core.
Claim 8
Dependent Claim
27 words
The invention defined in claim 6, wherein the axis of magnetic orientation of said permanent magnet is disposed in the direction of the axis of said core.
Claim 9
Dependent Claim
17 words
The invention defined in claim 7, wherein said permanent magnet is disposed in contact with said core.
Claim 10
Dependent Claim
23 words
The invention defined in claim 7, wherein said permanent magnet is movably mounted in spaced relation to the other end of said core.
Claim 11
Dependent Claim
33 words
The invention defined in claim 4, wherein said pole piece comprises one end of an elongated core and said coil for pre-magnetizing said core is disposed at the other end of said core.
Claim 12
Dependent Claim
32 words
The invention defined in claim 4, wherein at least a portion of said core is elongated, said measuring coil encircling said elongated portion and said pre-magnetizing coil surrounding said last mentioned coil.
Claim 13
Dependent Claim
23 words
The invention defined in claim 1, wherein the saturated magnetization of said soft magnetic material has a value of less than 1.4 Tesla.
Claim 14
Dependent Claim
21 words
The invention defined in claim 1, wherein the coercive field intensity of said soft magnetic material is less than 3.0 amperes/cm.
Claim 15
Dependent Claim
23 words
The invention defined in claim 1, wherein said soft magnetic material comprises an alloy of iron and between 13% and 18% of aluminum.
Claim 16
Dependent Claim
38 words
The invention defined in claim 14, wherein said alloy comprises approximately 16% of aluminum, the saturation magnetization having a value of between 0.5 and 1.0 Tesla and the coercive field intensity having a value less than 1.0 ampere/cm.
Claim 17
Dependent Claim
35 words
The invention defined in claim 1, wherein said means for pre-magnetizing said core comprises a permanent magnet having a coercive field intensity of more than 400 amperes/cm mounted in the magnetic field of said core.
Claim 18
Dependent Claim
20 words
The invention defined in claim 16, wherein the coercive field intensity of said permanent magnet is more than 1000 amperes/cm.
Claim 19
Dependent Claim
33 words
The invention defined in claim 1, wherein said means for pre-magnetizing said core comprises a permanent magnet mounted in the magnetic field of said core, said permanent magnet including a temperature compensating shunt.
Claim 20
Dependent Claim
35 words
The invention defined in claim 1, wherein said means for subjecting said sOft magnetic core to an alternating magnetic field comprises high frequency oscillator circuit means, said measuring coil being connected in said circuit means.
Claim 21
Dependent Claim
23 words
The invention defined in claim 1, wherein said two dissimilar materials comprise a non-magnetic layer to be measured applied to a ferromagnetic base.
Claim 22
Dependent Claim
16 words
The invention defined in claim 20, wherein said layer to be measured comprises electrically conductive material.
Claim 23
Dependent Claim
16 words
The invention defined in claim 20, wherein said layer to be measured comprises electrically insulating material.
Claim 24
Dependent Claim
25 words
The invention defined in claim 1, wherein said two dissimilar materials comprise a non-magnetic electrically insulating material to be measured applied to a non-magnetic base.
Claim 25
Dependent Claim
25 words
The invention defined in claim 1, wherein said two dissimilar materials comprise a non-magnetic electrically conductive material to be measured applied to a non-magnetic base.
Claim 26
Dependent Claim
40 words
The invention defined in claim 1, wherein said soft magnetic material comprises an alloy of iron, aluminum and silicon, the total amount of aluminum and silicon varying between 13% and 18%, the silicon not exceeding 8% of the aluminum content.
Claim 27
Dependent Claim
62 words
The invention defined in claim 1, wherein said soft magnetic material comprises an alloy of iron, aluminum and silicon, the total amount of aluminum and silicon being approximately 16%, the silicon not exceeding 8% of the aluminum content, the saturation magnetization having a value of between 0.5 and 1.0 Tesla and the coercive field intensity having a value less than 1.0 ampere/cm.
References Cited (Backward Citations)
US3405353A
Cited
US3761804A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |