US5376774A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low emission induction heating coil
Assignee: Electric Power Research Institute
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Filing: 1993-01-08
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Granted: 1994-12-27
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Expires: 2013-01-08
Abstract
Abstract Solenoid coils are provided that produce relatively low irradiation of electromagnetic fields with intense fields internally thereof for purposes of heating a metallic element, preferably a ferromagnetic element having a Curie temperature selected for the purpose for which the coil structure is to be employed, the coil structure in one embodiment comprising two coaxial coils of substantially equal diameter interconnected to produce in response to an alternating current being applied thereto out of phase magnetic fields that do not substantially interfere with one another as a result of the spacing between the coils. In a second embodiment the two coils are located between two additional coils that buck axial fields thereby together with fall off of the fields as the cube of the distance from the main coils provide a structure with low external radiation. The method of forming the first coil structure includes winding a pancake coil in the form of a spiral, rotating out of the plane of the coil the innermost leg of the spiral to provide the desired spacing of the coils, forming the pancake into a cylindrical shape with the cross members of the pancake being laid one over the other to provide cancellation of the fields produced by these members.
Inventors
- 👤 Thomas H. McGaffigan
- 👤 Frank A. Doljack
- 👤 Cristian C. Filimon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:58
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/02; H05B6/36; H05B6/362; B; B29; B29C; B29C65/00; B29C65/02; B29C65/34; B29C65/36; B29C65/3668; B29C65/3672; B29C65/3676; B29C66/00; B29C66/70; B29C66/73; B29C66/739; B29C66/7392; H05B6/06; H05B6/062; H05B6/065; H05B6/10; H05B6/12; H05B6/1209; H05B6/1245; Y; Y02; Y02B; Y02B40/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
52 words
A griddle comprising a generally flat ferromagnetic plate, a flat coil structure generally parallel to and electrically insulated from said ferromagnetic plate, said coil structure including at least two flat, rectangular spiral coils abutting one another, and means interconnecting said coils so that currents in said coils flow in the same direction.
Claim 2
Dependent Claim
52 words
A griddle comprising a generally flat ferromagnetic plate, a flat coil structure generally parallel to and electrically insulated from said ferromagnetic plate, said coil structure including at least two flat, rectangular spiral coils abutting one another, and means interconnecting said coils so that currents in said coils flow in the same direction.
Claim 3
Dependent Claim
37 words
A griddle according to claim 1 wherein said coil structure includes four coils in a two by two array, said coils interconnected such that current in each coil flows in the same direction as both adjacent coils.
Claim 4
Dependent Claim
70 words
A flat pancake coil structure comprising an even number of flat rectangular pancake coils of an equal number of turns; said coils abutting one another, said turns being in rectangular spiral form with a length of an outermost turn of each of two abutting coils being common to both said abutting coils, said common outermost length interconnecting said coils such that current flows in the same direction in said coils.
Claim 5
Dependent Claim
70 words
A flat pancake coil structure comprising an even number of flat rectangular pancake coils of an equal number of turns; said coils abutting one another, said turns being in rectangular spiral form with a length of an outermost turn of each of two abutting coils being common to both said abutting coils, said common outermost length interconnecting said coils such that current flows in the same direction in said coils.
Claim 6
Dependent Claim
16 words
A pancake coil according to claim 3 wherein there are four such coils arranged in squares.
Claim 7
Dependent Claim
22 words
A pancake coil according to claim 3 further comprising means for connecting a source of current to innermost ends of adjacent coils.
Claim 8
Dependent Claim
64 words
A flat pancake coil structure comprising an even number of flat rectangular pancake coils of an equal number of turns, said turns being in a rectangular spiral configuration each said coil having an outer turn of the spiral of each coil abutting one another over their lengths and electrically interconnected such that the current flowing in each outer turn flows in the same direction.
Claim 9
Dependent Claim
64 words
A flat pancake coil structure comprising an even number of flat rectangular pancake coils of an equal number of turns, said turns being in a rectangular spiral configuration each said coil having an outer turn of the spiral of each coil abutting one another over their lengths and electrically interconnected such that the current flowing in each outer turn flows in the same direction.
Claim 10
Dependent Claim
76 words
A flat pancake coil structure comprising four rectangular coils arranged in a generally square configuration, said square configuration comprising two groups of two interconnected coils abutting one another such that all abutting turns have the current flowing therein in the same direction, the innermost turn of one coil of each group being interconnected, and an innermost turn of a different coil of each group having means to connect the coils across a source of alternating current.
Claim 11
Dependent Claim
76 words
A flat pancake coil structure comprising four rectangular coils arranged in a generally square configuration, said square configuration comprising two groups of two interconnected coils abutting one another such that all abutting turns have the current flowing therein in the same direction, the innermost turn of one coil of each group being interconnected, and an innermost turn of a different coil of each group having means to connect the coils across a source of alternating current.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-12-26 | 1998-06-27 | 1998-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-26 | 2002-06-27 | 2002-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-26 | 2006-06-27 | 2006-12-27 | $7700.00 | Window Closed / Lapsed |