US3671902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shielded inductive device
Assignee: General Electric Co
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Filing: 1971-05-25
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Granted: 1972-06-20
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Expires: 1991-05-25
Abstract
Abstract Cylindrical superconductive coil is shielded to provide net zero magnetic field exterior of a cylindrical shield located a predetermined distance from the coil by winding about the shield, and about the ends thereof, winding which carry predetermined currents sufficient to just neutralize the external field due to the current in the coil at the shield.
Inventors
- 👤 Willem F Westendorp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:20
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/42; G01R33/421; G01R33/4215; G01R33/38; G01R33/381; G01R33/3815; Y; Y10; Y10S; Y10S336/00; Y10S336/01; Y10S505/00; Y10S505/825; Y10S505/872
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
196 words
A magnetically shielded inductive device which exhibits no effective magnetic flux exterior thereof and comprising: a. a cylindrical inductance coil having a longitudinal axis, an average winding radius, a winding length and a winding thickness; b. a magnetic shield surrounding said cylindrical coil and comprising, b1. first and second sets of concentric windings concentric with said longitudinal axis and with one another disposed in two planes normal to said axis at each end of said cylindrical coil and at a first predetermined distance from either end thereof; b2. a second plurality of windings concentric with said axis and lying in a cylindrical surface between the planes of said first and second sets of concentric windings and laterally surrounding said cylindrical coil; c. the windings of said shield being disposed from the exterior of said cylindrical coil in all directions a distance of at least half said average winding radius; and d. means supplying a current within the respective windings of said shield sufficient to produce a resultant magnetic flux equal and opposite to the magnetic flux thereat from said cylindrical coil so that total flux at a point immediately exterior of said shield is substantially zero.
Claim 2
Dependent Claim
196 words
A magnetically shielded inductive device which exhibits no effective magnetic flux exterior thereof and comprising: a. a cylindrical inductance coil having a longitudinal axis, an average winding radius, a winding length and a winding thickness; b. a magnetic shield surrounding said cylindrical coil and comprising, b1. first and second sets of concentric windings concentric with said longitudinal axis and with one another disposed in two planes normal to said axis at each end of said cylindrical coil and at a first predetermined distance from either end thereof; b2. a second plurality of windings concentric with said axis and lying in a cylindrical surface between the planes of said first and second sets of concentric windings and laterally surrounding said cylindrical coil; c. the windings of said shield being disposed from the exterior of said cylindrical coil in all directions a distance of at least half said average winding radius; and d. means supplying a current within the respective windings of said shield sufficient to produce a resultant magnetic flux equal and opposite to the magnetic flux thereat from said cylindrical coil so that total flux at a point immediately exterior of said shield is substantially zero.
Claim 3
Dependent Claim
22 words
The device of claim 1 wherein the currents in each of the said pluralities of windings are independently established at individual values.
Claim 4
Dependent Claim
18 words
The device of claim 1 wherein the currents in each of said windings are equal to one another.
Claim 5
Dependent Claim
14 words
The device of claim 3 wherein said windings are connected for common current flow.
Claim 6
Dependent Claim
22 words
The device of claim 4 wherein said current in said windings is identical with current in the windings of said cylindrical coil.
Claim 7
Dependent Claim
20 words
The device of claim 5 wherein said shield windings and said cylindrical coil windings are connected for common current flow.
Claim 8
Dependent Claim
17 words
The device of claim 1 wherein said cylindrical windings and said shield coils are of superconducting material.
Claim 9
Dependent Claim
10 words
The device of claim 7 wherein said material is Nb3Sn.
Claim 10
Dependent Claim
33 words
The device of claim 1 wherein each of said coils of said first and second plurality of coils is constituted of a plurality of windings having an effective locus at a calculated point.
Claim 11
Independent Claim
241 words
A method of providing a magNetic shield in the form of a cylindrical array of circular coils about a cylindrical inductance coil which shield is effective to substantially neutralize leakage flux from said cylindrical coil at the surface of said shield which method comprises: a. establishing an origin of coordinates at the center of a cylindrical coil having an average winding radius of a, a winding thickness of b, and a winding length of c; b. locating a first plurality of two n circular shield coils symmetrically located about the ends and cylindrical surface of said cylindrical shield, b1. each of said coils having a location in an orthogonal system of coordinates based upon said origin; c. establishing a second plurality of hypothetical coils equal in number to said first plurality of circular coils and exterior thereof in said coordinate system; d. establishing a plurality of n equations having n terms each of the form where A is a coefficient of mutual inductance between first circular coils and hypothetical coils, i and j are indices of individual circular and hypothetical coils respectively, X is the current in a particular indicated circular coil of the shield, and C is the flux at the jth hypothetical coil due to current in the cylindrical coil; e. solving said equations for the respective currents; and f. modifying the position of respective circular shield coils and repeating steps a - e until said currents are optimum.
Claim 12
Independent Claim
241 words
A method of providing a magNetic shield in the form of a cylindrical array of circular coils about a cylindrical inductance coil which shield is effective to substantially neutralize leakage flux from said cylindrical coil at the surface of said shield which method comprises: a. establishing an origin of coordinates at the center of a cylindrical coil having an average winding radius of a, a winding thickness of b, and a winding length of c; b. locating a first plurality of two n circular shield coils symmetrically located about the ends and cylindrical surface of said cylindrical shield, b1. each of said coils having a location in an orthogonal system of coordinates based upon said origin; c. establishing a second plurality of hypothetical coils equal in number to said first plurality of circular coils and exterior thereof in said coordinate system; d. establishing a plurality of n equations having n terms each of the form where A is a coefficient of mutual inductance between first circular coils and hypothetical coils, i and j are indices of individual circular and hypothetical coils respectively, X is the current in a particular indicated circular coil of the shield, and C is the flux at the jth hypothetical coil due to current in the cylindrical coil; e. solving said equations for the respective currents; and f. modifying the position of respective circular shield coils and repeating steps a - e until said currents are optimum.
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |