US3844860A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making an electric power cable
Assignee: Balfour Beatty PLC
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Filing: 1972-03-29
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Granted: 1974-10-29
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Expires: 1992-03-29
Abstract
Abstract Polymer/fibre laminated tapes suitable for use in the dielectric of power cables are pre-swollen with an appropriate swelling agent to avoid or reduce swelling when they contact the cable impregnant. Preferably the tapes are exposed to vapour of the swelling agent, and this technique is advantageous also for unlaminated plastic tapes; in appropriate laminates, however, there is a special advantage in that the fibrous layer may be kept free of swelling agent. In the case of paper/polypropylene laminates pre-swelling permits reduction of the interfacial pressure in the lapped tapes of the cable below 0.6 MN/m2 and thereby makes it possible to make a flexible oil-filled cable insulated with this material.
Inventors
- 👤 D Edwards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:30
CPC Classifications
H; H01; H01B; H01B13/00; H01B13/30; H01B3/00; H01B3/002; H01B3/18; H01B3/30; H01B3/44; H01B3/441; H01B7/00; H01B7/02; H01B7/0208; H01B7/0225; H01B7/17; H01B7/28; H01B7/282; H01B7/285; H01B7/2855; Y; Y02; Y02A; Y02A30/00; Y02A30/14
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
100 words
A METHOD OF MAKING AN ELECTRIC POWER CABLE CORE COMPRISING THE STEPS OF LAPPING ON TO A CONDUCTOR A PLURALITY OF ELECTRICALLY INSULATING TAPES EACH COMPRISING AT LEAST ONE LAYER OF FIBROUS MATERIAL AND AT LEAST ONE POLYMERIC LAYER, SAID POLYMERIC LAYER CONTANING AN ABSORBED ELECTRICALLY INSULATING SWELLING AGENT THAT DOES NOT SWELL SAID FIBROUS MATERIAL AND IMPREGNATING THE RESULTANT DIELECTRIC BODY WITH AN INSULATING LIQUID IMPREGNANT THAT SWELLS THE MATERIAL OF SAID POLYMERIC LAYERS BUT NOT SAID FIBROUS MATERIAL, SAID SWELLING AGENT BEING SELECTED TO REDUCE THE DEGREE OF SWELLING THAT OCCURS UPON CONTACT WITH THE SAID LIQUID IMPREGNANT.
Claim 2
Independent Claim
100 words
A METHOD OF MAKING AN ELECTRIC POWER CABLE CORE COMPRISING THE STEPS OF LAPPING ON TO A CONDUCTOR A PLURALITY OF ELECTRICALLY INSULATING TAPES EACH COMPRISING AT LEAST ONE LAYER OF FIBROUS MATERIAL AND AT LEAST ONE POLYMERIC LAYER, SAID POLYMERIC LAYER CONTANING AN ABSORBED ELECTRICALLY INSULATING SWELLING AGENT THAT DOES NOT SWELL SAID FIBROUS MATERIAL AND IMPREGNATING THE RESULTANT DIELECTRIC BODY WITH AN INSULATING LIQUID IMPREGNANT THAT SWELLS THE MATERIAL OF SAID POLYMERIC LAYERS BUT NOT SAID FIBROUS MATERIAL, SAID SWELLING AGENT BEING SELECTED TO REDUCE THE DEGREE OF SWELLING THAT OCCURS UPON CONTACT WITH THE SAID LIQUID IMPREGNANT.
Claim 3
Dependent Claim
18 words
A method as claimed in claim 1 wherein said insulating liquid impregnant is identical with said swelling agent.
Claim 4
Independent Claim
87 words
A method of making an electrical power cable comprising the successive steps of i. lapping onto a conductor to form a dielectric body a plurality of tapes each comprising two paper layers and, sandwiched between and bonded to them, a layer coNsisting mainly of a polymer derived predominantly from propylene and containing an absorbed hydrocarbon oil that does not swell paper, ii. impregnating said dielectric body with a hydrocarbon insulating oil that does not swell paper, and iii. applying a fluid-tight sheath after step (1) is complete.
Claim 5
Independent Claim
87 words
A method of making an electrical power cable comprising the successive steps of i. lapping onto a conductor to form a dielectric body a plurality of tapes each comprising two paper layers and, sandwiched between and bonded to them, a layer coNsisting mainly of a polymer derived predominantly from propylene and containing an absorbed hydrocarbon oil that does not swell paper, ii. impregnating said dielectric body with a hydrocarbon insulating oil that does not swell paper, and iii. applying a fluid-tight sheath after step (1) is complete.
Claim 6
Dependent Claim
39 words
A method as claimed in claim 3 comprising the preliminary step of introducing said absorbed hydrocarbon oil into said polymer layer without introducing said oil into said paper layers by exposing said tapes to the vapour of said oil.
Claim 7
Independent Claim
91 words
A method of making an electric power cable comprising the successive steps of i. lapping onto a conductor to form a dielectric body a plurality of electrically insulating tapes each comprising two paper layers and, sandwiched between and bonded to them, a layer consisting mainly of a high density polymer derived predominantly from ethylene and containing an absorbed hydrocarbon oil that does not swell paper, ii. impregnating said dielectric body with a hydrocarbon insulating oil that does not swell paper, and iii. applying a fluid-tight sheath after step (i) is complete.
Claim 8
Independent Claim
91 words
A method of making an electric power cable comprising the successive steps of i. lapping onto a conductor to form a dielectric body a plurality of electrically insulating tapes each comprising two paper layers and, sandwiched between and bonded to them, a layer consisting mainly of a high density polymer derived predominantly from ethylene and containing an absorbed hydrocarbon oil that does not swell paper, ii. impregnating said dielectric body with a hydrocarbon insulating oil that does not swell paper, and iii. applying a fluid-tight sheath after step (i) is complete.
Claim 9
Dependent Claim
39 words
A method as claimed in claim 5 comprising the preliminary step of introducing aid absorbed hydrocarbon oil into said polymer layer without introducing said oil into said paper layers by exposing said tapes to the vapour of said oil.
Claim 10
Independent Claim
104 words
A method of making an electric cable comprising the successive steps of i. preparing electrically insulating laminated tapes each consisting of a layer of a plastics material sandwiched between and bonded to two layers of fibrous material, ii. exposing said tapes to the vapour of an insulating liquid that swells said plastics material but not said fibrous material until said plastic layer has taken up a substantial amount of said insulating liquid, iii. lapping said tapes onto a conductor to form a cable core, iv. impregnating the core with the said insulating liquid and v. applying a fluid-tight sheath after completion of step (iii).
Claim 11
Independent Claim
104 words
A method of making an electric cable comprising the successive steps of i. preparing electrically insulating laminated tapes each consisting of a layer of a plastics material sandwiched between and bonded to two layers of fibrous material, ii. exposing said tapes to the vapour of an insulating liquid that swells said plastics material but not said fibrous material until said plastic layer has taken up a substantial amount of said insulating liquid, iii. lapping said tapes onto a conductor to form a cable core, iv. impregnating the core with the said insulating liquid and v. applying a fluid-tight sheath after completion of step (iii).
References Cited (Backward Citations)
GB1078023A
Cited
GB1043328A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |