Patent US3970904A successfully refreshed from Google Patents.
US3970904A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impregnated capacitor and method of manufacture
Assignee: Johnson and Phillips Capacitors Ltd
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Filing: 1974-06-06
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Granted: 1976-07-20
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Expires: 1994-06-06
Abstract
Abstract A capacitor element is made by interwinding electrode foils and non-porous dielectric films, without interposed paper wicks. The foils and films are wound at different tensions so that transverse passages are formed between adjacent surfaces within the element; when the element is subsequently impregnated with dielectric liquid, those passages facilitate entry of the liquid between the various foils and films and assist proper permeation. The dielectric film and dielectric liquid are preferably polypropylene and mineral oil respectively.
Inventors
- 👤 John Edward Murfitt
- 👤 Alastair Martin Pitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:14
CPC Classifications
H; H01; H01G; H01G13/00; H01G13/04; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/14; H01G4/18; Y; Y10; Y10T; Y10T29/00; Y10T29/43; Y10T29/435
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
113 words
In a method of making a capacitor element comprising the steps of a. interwinding electrode foils and layers of substantially non-porous dielectric film, to form a winding, and b. impregnating said winding with a dielectric liquid, the improvement according to which said foils and said layers in said winding are interwound under conditions such that the foils and films of said winding are at sufficiently different tensions that at least one of each pair of adjacent foil and film surfaces is corrugated during winding to form passages extending transversely to the lengths of said layers between said adjacent surfaces, which passages assist entry of said impregnating liquid between said foils and said layers.
Claim 2
Dependent Claim
113 words
In a method of making a capacitor element comprising the steps of a. interwinding electrode foils and layers of substantially non-porous dielectric film, to form a winding, and b. impregnating said winding with a dielectric liquid, the improvement according to which said foils and said layers in said winding are interwound under conditions such that the foils and films of said winding are at sufficiently different tensions that at least one of each pair of adjacent foil and film surfaces is corrugated during winding to form passages extending transversely to the lengths of said layers between said adjacent surfaces, which passages assist entry of said impregnating liquid between said foils and said layers.
Claim 3
Dependent Claim
27 words
A method according to claim 1, in which each layer is constituted by a plurality of films, of which there are at least two at different tensions.
Claim 4
Dependent Claim
24 words
A method according to claim 2, in which each layer comprises at least three films, of which at least two have the same tension.
Claim 5
Dependent Claim
39 words
A method according to claim 3, in which the films of equal tension are adjacent one another, and are overlain by a film or foil at a higher tension, so that passage-forming corrugations are formed between those two films.
Claim 6
Dependent Claim
18 words
A method according to claim 2, in which the foils and films are wound at the differing tensions.
Claim 7
Dependent Claim
32 words
A method according to claim 2, in which the films are wound at substantially the same tension from reels on at least two of which the films are pretensioned at different values.
Claim 8
Dependent Claim
21 words
A method according to claim 1 in which, the winding prior to impregnation is so clamped that it has predetermined dimensions.
Claim 9
Dependent Claim
12 words
A method according to claim 1, in which the film is polypropylene.
Claim 10
Dependent Claim
15 words
A method according to claim 1, in which said dielectric liquid is an impegnating oil.
Claim 11
Dependent Claim
59 words
A capacitor element comprising electrode foils interwound with separating layers of substantially non-porous dielectric film, the foil and layers being at different elongations and the film layers consequently having randomly arranged transverse corrugations forming passages between the layers and foils, and each layer consisting of a plurality of films, of which there are at least two at different elongations.
Claim 12
Dependent Claim
59 words
A capacitor element comprising electrode foils interwound with separating layers of substantially non-porous dielectric film, the foil and layers being at different elongations and the film layers consequently having randomly arranged transverse corrugations forming passages between the layers and foils, and each layer consisting of a plurality of films, of which there are at least two at different elongations.
Claim 13
Dependent Claim
17 words
A capacitor element according to claim 10, in which the element has a space factor of 3%.
Claim 14
Dependent Claim
25 words
A capacitor element according to claim 10, in which each layer comprises at least three films, of which at least two have the same elongation.
Claim 15
Dependent Claim
13 words
A capacitor element according to claim 10, in which the film is polypropylene.
Claim 16
Independent Claim
110 words
A method of making a capacitor, comprising the steps of a. forming at least one capacitor element winding by interwinding at differing tensions electrode foils and layers of substantially non-porous dielectric film, and thereby forming passages extending transversely to the lengths of said layers between adjacent foil and dielectric layer surfaces within said winding, b. placing said at least one capacitor element winding within an impregnation tank, c. subjecting the interior of said tank to an inert gas at super-atmospheric pressure, and d. introducing an impregnating dielectric liquid to said tank to impregnate said at least one winding, entry of said liquid into said winding being assisted by said passages.
Claim 17
Independent Claim
110 words
A method of making a capacitor, comprising the steps of a. forming at least one capacitor element winding by interwinding at differing tensions electrode foils and layers of substantially non-porous dielectric film, and thereby forming passages extending transversely to the lengths of said layers between adjacent foil and dielectric layer surfaces within said winding, b. placing said at least one capacitor element winding within an impregnation tank, c. subjecting the interior of said tank to an inert gas at super-atmospheric pressure, and d. introducing an impregnating dielectric liquid to said tank to impregnate said at least one winding, entry of said liquid into said winding being assisted by said passages.
Claim 18
Independent Claim
130 words
A method of making a capacitor, comprising the steps of a. forming at least one capacitor element winding by interwinding at substantially the same tension electrode foils and substantially non-porous dielectric films from reels of said foils and films, on at least two of said reels said films being pretensioned at different values, and thereby forming passages extending transversely to the lengths of said foils between adjacent foil and film surfaces within said winding, b. placing said at least one capacitor element winding within an impregnation tank, c. subjecting the interior of said tank to an inert gas at super-atmospheric pressure, and d. introducing an impregnating dielectric liquid to said tank to impregnate said at least one winding, entry of said liquid into said winding being assisted by said passages.
Claim 19
Independent Claim
130 words
A method of making a capacitor, comprising the steps of a. forming at least one capacitor element winding by interwinding at substantially the same tension electrode foils and substantially non-porous dielectric films from reels of said foils and films, on at least two of said reels said films being pretensioned at different values, and thereby forming passages extending transversely to the lengths of said foils between adjacent foil and film surfaces within said winding, b. placing said at least one capacitor element winding within an impregnation tank, c. subjecting the interior of said tank to an inert gas at super-atmospheric pressure, and d. introducing an impregnating dielectric liquid to said tank to impregnate said at least one winding, entry of said liquid into said winding being assisted by said passages.
Claim 20
Dependent Claim
48 words
A method of making a capacitor according to claim 14, in which a number of said capacitor element windings are placed in juxtaposition within a capacitor casing with the outer foils of contiguous windings having the same polarity, and said capacitor casing is placed within said impregnation tank.
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) | 1979-07-20 | 1980-01-19 | 1980-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-20 | 1984-01-19 | 1984-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-20 | 1988-01-19 | 1988-07-20 | $7700.00 | Window Closed / Lapsed |