US3773965A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric cables
Assignee: BRIT INSULATED CALLENDER CABLE
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Filing: 1972-02-01
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Granted: 1973-11-20
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Expires: 1992-02-01
Abstract
Abstract High voltage electric cables of the kind having a laminated dielectric comprising lappings of insulating tape impregnated with an insulating liquid enclosed in a liquid-impervious sheath or pipe. Such laminated dielectric is most commonly built up from lappings of paper tape although proposals have been made to use plastics film along or interleaved with paper and it has been proposed that plastics film having on one or both sides an adherent layer of fibrous material should be used. More particularly the invention relates to such a cable in which the insulating liquid is a liquefied gas which, in addition to forming part of the dielectric, acts as a cooling medium thus increasing the cable rating for a given conductor cross-section.
Inventors
- 👤 E Reynolds
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:19
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/12; H; H01; H01B; H01B7/00; H01B7/02; H01B7/0233; B32B1/00; B32B1/08; B32B15/00; B32B15/04; B32B15/046; B32B15/20; B32B27/06; B32B27/065; B32B27/30; B32B27/304; B32B27/32; B32B3/00; B32B3/26; B32B3/28; B32B5/00; B32B5/18; H01B13/00; H01B13/30; H01B7/17; H01B7/29; H01B9/00; H01B9/02; H01B9/027; H01B9/06; H01B9/0605; H01B9/0644; H01B9/0655; B32B2307/00; B32B2307/30; B32B2307/304; B32B2323/00; B32B2323/10; B32B2327/00; B32B2327/06
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
23 words
A high voltage cable as claimed in claim 1, wherein the liquefied gas is maintained at a pressure of at least two atmospheres.
Claim 2
Dependent Claim
49 words
A high voltage cable as claimed in claim 1, in which an electrically conductive screen overlies the conductor and an electrically conductive screen overlies the laminated dielectric, wherein at least one of the conductor and dielectric screens is formed of at least one layer of single ply semi-conducting tapes.
Claim 3
Dependent Claim
49 words
A high voltage cable as claimed in claim 1, wherein the tapes forming at least part of the laminated dielectric are each a prestressed laminate formed by trapping an extruded molten web of plastics material as it leaves an extruded, between two paper sheets forming part of the laminate.
Claim 4
Dependent Claim
33 words
A high voltage cable as claimed in claim 1, wherein each cellulosic paper tape of the tapes forming at least part of the laminated dielectric has a density less than 0.85 gcm 3.
Claim 5
Dependent Claim
53 words
A high voltage cable as claimed in claim 5, wherein each cellulosic paper tape of the tapes forming at least part of the laminated dielectric is an uncalendered electrical grade paper of intermediate fibre length of a density within the range 0.7 -0.85 gcm 3 and an impermeability greater than 10,000 Gurley seconds/mil.
Claim 6
Dependent Claim
58 words
A high voltage cable as claimed in claim 1, wherein cellulosic paper tapes forming at least part of the laminated dielectric are loaded with a material selected from the group of materials consisting of, aluminium oxide and other active metal oxides, hydrated metal oxides, hydroxides, carbonates or basic carbonates having sorptive powers comparable with that of aluminium oxide.
Claim 7
Dependent Claim
27 words
A high voltage cable as claimed in claim 1, wherein the plastics film of the tapes forming at least part of the laminated dielectric is of polyethylene.
Claim 8
Dependent Claim
27 words
A high voltage cable as claimed in claim 1, wherein the plastics film of the tapes forming at least part of the laminated dielectric is of polypropylene.
Claim 9
Dependent Claim
26 words
A high voltage cable as claimed in claim 1, wherein the plastics film of the tapes forming at least part of the laminated dielectric is irradiated.
Claim 10
Dependent Claim
33 words
A high voltage cable as claimed in claim 1, wherein the liquefied gas is selected from the group of liquefied gases consisting of liquid hydrogen, liquid nitrogen, liquid helium, and liquid natural gas.
Claim 11
Dependent Claim
24 words
A high voltage cable as claimed in claim 1, wherein the liquefied gas is selected from the group consisting of trifluoromethane, trifluorochloromethane, and difluorochloromethane.
Claim 12
Dependent Claim
85 words
A high voltage cable comprising at least one conductor and a laminated dielectric surrounding the conductor, wherein the dielectric is built up at least in part from tapes comprising an imperforate plastics film having bonded to each of its major surfaces a cellulosic paper tape, impregnated with a liquefied gas which is maintained at a pressure substantially greater than that of the atmosphere and the dielectric is surrounded by at least one layer of thermal insulating material which constitutes a component part of the cable.
Claim 13
Dependent Claim
37 words
A high voltage cable as claimed in claim 13, in which the cable is enclosed in a sheath, wherein the layer or at least one of the layers of thermal insulating material lies inside the cable sheath.
Claim 14
Dependent Claim
119 words
A high voltage cable comprising at least one conductor, an electrically conductive screen overlying the conductor , a laminated dielectric surrounding the screened conductor, and a electrically conductive screen overlying the laminate dielectric, wherein the dielectric is built up at least in part from tapes comprising an imperforate plastics film having bonded to each of its major surfaces a cellulosic paper tape, impregnated with a liquefied gas, which is maintained at a pressure substantially greater than that of the atmosphere, and wherein at least one of the conductor and dielectric screens comprises at least one layer of laminated tape comprising an imperforate plastics film having bonded to each of its major surfaces a cellulosic paper tape rendered electrically conductive.
Claim 15
Dependent Claim
29 words
A high voltage cable as claimed in claim 15, wherein all three layers of the or each laminated tape of the screen are loaded with an electrically conductive material.
Claim 16
Dependent Claim
44 words
A high voltage cable as claimed in claim 15, wherein at least one of the screen includes a laminated tape immediately adjacent the laminated dielectric of which only the plastics film and the paper tape remote from the laminated dielectric are rendered electrically conductive.
Claim 17
Dependent Claim
62 words
A high voltage cable as claimed in claim 17, wherein the paper tape of the or each screen that is contiguous with the laminated dielectric is loaded with a material selected from the group of materials consisting of aluminium oxide and other active metal oxides, hydrated metal oxides, hydroxides, carbonates or basic carbonates having sorptive powers comparable with that of aluminium oxide.
Claim 18
Dependent Claim
30 words
A high voltage cable as claimed in claim 15, wherein at least one layer of thermal insulating material surrounds the laminated dielectric and constitutes a component part of the cable.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |