US3843830A - Electric cable with corrugated sheath and semi-conductive protective layer between the sheath and the core - Google Patents

Electric cable with corrugated sheath and semi-conductive protective layer between the sheath and the core Download PDF

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Publication number
US3843830A
US3843830A US00403962A US40396273A US3843830A US 3843830 A US3843830 A US 3843830A US 00403962 A US00403962 A US 00403962A US 40396273 A US40396273 A US 40396273A US 3843830 A US3843830 A US 3843830A
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United States
Prior art keywords
sheath
core
tube
corrugations
cable
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Expired - Lifetime
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US00403962A
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English (en)
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P Priaroggia
G Maschio
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Pirelli and C SpA
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Pirelli SpA
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Assigned to SOCIETA' PIRELLI S.P.A., A COMPANY OF ITALY reassignment SOCIETA' PIRELLI S.P.A., A COMPANY OF ITALY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: INDUSTRIE PIRELLI S.P.A.
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B9/00Power cables
    • H01B9/02Power cables with screens or conductive layers, e.g. for avoiding large potential gradients

Definitions

  • the present invention relates to improvements in electric cables provided with a metal sheath, in particular, a corrugated aluminum sheath, and of the type described in co-pending application Ser. No. 162,199, filed July 13, 1971, and entitled ELECTRIC CABLE WITH CORRUGATED METALLIC SHEATH, now U.S. Pat. No. 3,766,309.
  • the invention is applicable to high voltage power cables and especially to Millikentype cables.
  • U.S. Pat. No. 3,766,309 describes an electric cable comprising a core, i.e., a conductor surrounded throughout its length by at least one layer of insulating material, which is surrounded by a corrugated metal sheath.
  • a soft tubular covering generally of the order of about one or more millimeters in radial dimension, covers said core, the corrugations of the sheath, at least for a part of their depth, penetrating into said soft tubular covering in order to provide a co-penetration of the latter and the sheath.
  • a preferred embodiment of the invention illustrated in said patent is an electric cable comprising a core contained in a corrugated metal sheath, in which said soft tubular covering for the core is made of crepe paper.
  • the possible slippage of the core with respect to the sheath, when the cable is installed in vertical direction, is substantially prevented.
  • the soft tubular covering in particular when it is made of crepe paper, has provided, in practice, very suitable for the dissipation of heat in the case of power cables subjected to thermal cycles, thereby avoiding undesired over-heating of the dielectric.
  • the principal object of the invention of the present application is to provide an electric cable having a corrugated metal sheath which is improved with respect to the electric cable described in said patent, the improvement being also applicable to high voltage power cables, in particular, to Milliken-type cables, and the improvement substantially eliminating the hereinforementioned disadvantages.
  • the object of the present invention is an improved electric cable comprising a core contained in a corrugated metal sheath, and of the type disclosed in said application, in which a soft tubular covering surrounds said core, the corrugations of the sheath, at least for a part of their depth, penetrating in said soft tubular covering so as to provide a co-penetration between the latter and the sheath, said cable being characterized in that said soft tubular covering is constituted by a material having a high electric conductivity with respect to a dielectric material.
  • the electric cable, said soft tubular covering, made of a material having a high electric conductivity is constituted by a winding of tapes of semi-conductive crepe paperfl-w-
  • said soft tuv bular covering, made of a material having a high electric conductivity is constituted by an internal winding of tapes of semi-conductive crepe paper and by an external winding of a cloth of glass fibers containing intercalated metal wires.
  • FIG. 1 represents, in longitudinal section, a single core, power cable having a core surrounded by a corrugated metal sheath and having an intermediate layer of semi-conductive crepe paper;
  • FIG. 2 represents, in longitudinal section, a Millikentype cable, provided with a corrugated aluminum sheath and a composite intermediate layer of semiconductive crepe paper and a cloth of glass fibers containing intercalated metal wires.
  • the cable represented in longitudinal section in FIG. 1 is a single core cable and comprises a core 10 and a corrugated sheath 1].
  • the sheath 11 illustrated in FIG. 1 has helical corrugations, the corrugations could be annular.
  • the core 10 comprises a stranded conductor 12, on which is wound a first, or internal, semi-conductive screen 13 surrounded by a dielectric layer 14, which, in turn, is surrounded by a second, or external, semi-conductive screen 15.
  • the core 10 is electrically complete, that is, except for the need to protect it from physical damage with a sheath 1 l, the core 10 may be used for carrying current between separated points.
  • the core 10 is protected from damage by the sheath 11, both during the application of the sheath 11 and during subsequent use and is prevented from slipping with respect to the sheath 1 1 by a soft tubular covering or layer 16, made of a material having a high electric conductivity as compared to ordinary insulation, e.g., it has a resistivity, MD, of from 30 to 5,000 ohm cm. and a bulk resistivity of from 3,000 to 500,000 ohm cm.
  • the covering 16 is constituted by a helical winding of tapes of semiconductive crepe paper thereby forming a tube of solid, self-sustaining and resilient material between the sheath 1] and the core 10.
  • the material of the covering 16 is different from the material of the layer 14 and is softer than the latter so as to permit deformation of the sheath 11 without substantial deformation of the layer 14.
  • the covering 16 frictionally engages the external screen 15 and the sheath 11, at least partially filling the corrugations of the sheath 11, and thereby prevents significant relative movement between the sheath 1 l and the core 10 when the cable is suspended by the sheath 11.
  • the shear strength of the covering 16 is such that it can prevent such relative movement without shearing of the covering 16 or the material thereof.
  • the normal exterior size of the covering 16 in the absence of deformation thereof is greater than the minimum diameter of the corrugations of the sheath 11.
  • the inner surface 16 of the soft, tubular, conductive covering 16 is in contact with the external semiconductive screen 15, and the outer surface 18 of said covering 16 is in contact with the internal surface of the corrugated sheath 11, at least along a helical surface in the form of a generally cylindrical helix of circular section,
  • the cable illustrated in FIG. 2 is of the type known to those skilled in the art as a MIlliken-type cable.
  • the core 20 is surrounded by a corrugated metal sheath 21 having annular corrugations, but the corrugations could be helical as illustrated in FIG. 1.
  • the conductor of the core 20 comprises three conductive strands 22 in the form of sectors which are helically would together about the longitudinal axis aa of the cable and defining a generally cylindrical passageway 23 which constitutes the duct for the supply of the cable impregnating fluid which may, for example, be sulfur hexa-fluoride, nitrogen, a mixture of sulfur hexafluoride and nitrogen, fluid oil, etc.
  • a metal tape 24 which maintains the sectors 22 in their cylindrical helix configuration, so that the cross-section of the conductor of the core 20 is kept as nearly circular as possible.
  • a metal tape 24 On the metal tape 24, there is a first, intemal, semi-conductive screen 25 surrounded by a dielectric layer 26 which, in turn, is surrounded by a second, external, semi-conductive screen 27.
  • the latter is protected by a soft, conductive, tubular covering 28 similar to, and for the same purposes as, the covering 16.
  • the soft, tubular covering 28 comprises an internal winding 29 of semiconductive crepe paper and an external winding 30 of a known type of cloth made of glass fibers and containing intercalated metal wires, namely, good electrically conductive elements which, extending from one part of the cloth to the other, can conductively interconnect
  • an internal winding 29 of semiconductive crepe paper and an external winding 30 of a known type of cloth made of glass fibers and containing intercalated metal wires, namely, good electrically conductive elements which, extending from one part of the cloth to the other, can conductively interconnect
  • An electric cable comprising at least one core including a conductor surrounded throughout substantially its length by at least one layer of insulating material and an external screening layer of at least semiconductive material surrounding said insulating layer,
  • a corrugated metal sheath surrounding said core and a tube comprising solid, at leat semi-conductive material intermediate said core and said sheath and in frictional engagement and electrical contact with said screening layer and said sheath and at least partially filling the two contiguous layers between which the cloth of glass fibers containing intercalated metal wires is interposed.
  • a conductive connection is established between the internal winding 29 of semiconductive crepe paper of the soft, tubular covering 28 and the corrugated sheath 21.
  • the cloth of glass fibers 30 containing intercalated metal wires has also the advantages of acting as a thermal and mechanical protector of the core 20 in the excorrugations of said sheath to prevent slipping of said core with respect to said sheath and to conductively interconnect said screening layer and said sheath, said tube beings self-sustaining, resilient and softer than the material of said core to permit defomiation of said tube by the corrugations of said sheath without substantial deformation of said core and said tube having a shear strength sufficient to prevent said slippage without shearing when said cable is suspended by said sheath.
  • An electric cable comprising at least one core including a conductor surrounded throughout its length by at least one layer of insulating material and an external screening layer of at least semi-conductive material surrounding said insulating layer, a corrugated metal sheath surrounding said core, and a tube of solid, at least semi-conductive, material intermediate said core and said sheath with the corrugations of said sheath embedded in said tube for preventing slipping of said core and said sheath relative to each other in a direction extending longitudinally of said cable when said cable is suspended by said sheath and for conductively interconnecting said screening layer and said sheath, said tube comprising at least one tape made of an insulating material different from that of said insulating layer, deformable by the corrugations of said sheath and having a normal exterior size in the absence of deformation thereof by said corrugations which is greater than the minimum diameter of said corrugations so that portions of said tube at least partially fill said corrugations and said tube encircling said core and having at least a portion of its interior
  • An electric cable comprising at least one core including a conductor surrounded throughout substantially its length by at least one layer of insulating material and an external screening layer of at least semiconductive material surrounding said insulating layer, a corrugated metal sheath surrounding said core and a tube of semi-conductive tape of crepe paper wound around said screening layer and intermediate said core and said sheath and in frictional engagement and electrical contact with said screening layer and said sheath and at least partially filling the corrugations of said sheath to prevent slipping of said core with respect to said sheath and to conductively interconnect said screening layer and said sheath, said tube being selfsustaining, resilient and softer than the material of said core to permit deformation of said tube by the corrugations of said sheath without substantial deformation of said core and said tube having a shear strength sufficient to prevent said slippage without shearing when said cable is suspended by said sheath 4.
  • An electric cable comprising at least one core including a conductor surrounded throughout substantially its length by at least one layer of insulating material and an external screening layer of at least semiconductive material surrounding said insulating layer, a corrugated metal sheath surrounding said core and a tube of semi-conductive tape of crepe paper wound around said screening layer and a further winding of glass fiber cloth containing intercalated metal wires wound around said tape and intermediate said core and said sheath and in frictional engagement and electrical contact with said screening layer and said sheath and at least partially filling the corrugations of said sheath to prevent slipping of said core with respect to said sheath and to conductively interconnect said screening layer and said sheath, said tube being self-sustaining, resilient and softer than the material of said core to permit deformation of said tube by the corrugations of said sheath without substantial deformation of said core and said tube having a shear strength sufficient to prevent said slippage without shearing when said cable is suspended by said sheath.
  • An electric cable comprising at least one core including a conductor surrounded throughout its length by at least one layer of insulating material and an external screening layer of at least semi-conductive material surrounding said insulating layer, a corrugated metal sheath surrounding said core, and a tube of solid, at least semi-conductive, material intermediate said core and said sheath with the corrugations of said sheath embedded in said tube for preventing slipping of said core and sid said tube for preventing slipping of said core and said sheath relative to each other in a direction extending longitudinally of said cable when said cable is suspended by said sheath and for conductively interconnecting said screening layer and said sheath, said tube comprising at least one tape made of an insulating material different from that of said insulating layer and being made of semi-conductive crepe paper and said tube being deformable by the corrugations of said sheath and having a normal exterior size in the absence of deformation thereof by said corrugations which is greater than the minimum diameter of said corrugations so that portions of said tube at

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US00403962A 1972-11-13 1973-10-05 Electric cable with corrugated sheath and semi-conductive protective layer between the sheath and the core Expired - Lifetime US3843830A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT31581/72A IT1044874B (it) 1972-11-13 1972-11-13 Cavo elettrico con guaina metallica ondulata perfezionato

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US00403962A Expired - Lifetime US3843830A (en) 1972-11-13 1973-10-05 Electric cable with corrugated sheath and semi-conductive protective layer between the sheath and the core

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US (1) US3843830A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS589521B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
AR (1) AR196699A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
BR (1) BR7308838D0 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CA (1) CA994442A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1395519A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IE (1) IE38504B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IT (1) IT1044874B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
SE (1) SE382519B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
ZA (1) ZA738653B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4020276A (en) * 1975-04-11 1977-04-26 Scal - Societe De Conditionnements En Aluminum Sealant barrier for electrical cables
US4059724A (en) * 1975-03-22 1977-11-22 Homare Ide Shield wire
US4145567A (en) * 1977-06-06 1979-03-20 General Cable Corporation Solid dielectric cable resistant to electrochemical trees
US4375632A (en) * 1980-01-31 1983-03-01 Sumitomo Electric Industries, Ltd. Ignition cables
JPH04300972A (ja) * 1990-11-29 1992-10-23 Bayer Ag 改善された染料粒状物の製造法
US5414215A (en) * 1992-01-28 1995-05-09 Filotex High frequency electric cable
US6255591B1 (en) * 1998-10-13 2001-07-03 Gerhard Ziemek Electric cables with metallic protective sheaths
WO2004013868A3 (en) * 2002-08-01 2004-04-15 Southwire Co Triaxial superconducting cable and termination therefor
EP2093775A1 (en) * 2008-02-20 2009-08-26 ABB Technology AG An electric power distribution cable and a power distribution arrangement provided therewith
CN102959644A (zh) * 2010-07-06 2013-03-06 瑞典爱立信有限公司 自支撑线缆
US20170352451A1 (en) * 2016-06-03 2017-12-07 AFC Cable Systems, Inc. Metal clad cable having parallel laid conductors
KR20180020550A (ko) * 2016-08-18 2018-02-28 엘에스전선 주식회사 전력 케이블
US20180190409A1 (en) * 2015-06-23 2018-07-05 Nkt Hv Cables Gmbh Electric Power Cable And A Process For The Production Of The Power Cable

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6144015U (ja) * 1984-08-24 1986-03-24 横河電機株式会社 耐圧防爆容器

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5126780Y2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) * 1971-03-05 1976-07-07

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4059724A (en) * 1975-03-22 1977-11-22 Homare Ide Shield wire
US4020276A (en) * 1975-04-11 1977-04-26 Scal - Societe De Conditionnements En Aluminum Sealant barrier for electrical cables
US4145567A (en) * 1977-06-06 1979-03-20 General Cable Corporation Solid dielectric cable resistant to electrochemical trees
US4375632A (en) * 1980-01-31 1983-03-01 Sumitomo Electric Industries, Ltd. Ignition cables
JPH04300972A (ja) * 1990-11-29 1992-10-23 Bayer Ag 改善された染料粒状物の製造法
US5414215A (en) * 1992-01-28 1995-05-09 Filotex High frequency electric cable
US6255591B1 (en) * 1998-10-13 2001-07-03 Gerhard Ziemek Electric cables with metallic protective sheaths
US20050173149A1 (en) * 2002-08-01 2005-08-11 Gouge Michael J. Triaxial superconducting cable and termination therefor
WO2004013868A3 (en) * 2002-08-01 2004-04-15 Southwire Co Triaxial superconducting cable and termination therefor
US20080179070A1 (en) * 2002-08-01 2008-07-31 Gouge Michael J Triaxial Superconducting Cable and Termination Therefor
EP2093775A1 (en) * 2008-02-20 2009-08-26 ABB Technology AG An electric power distribution cable and a power distribution arrangement provided therewith
CN102959644A (zh) * 2010-07-06 2013-03-06 瑞典爱立信有限公司 自支撑线缆
US20130213687A1 (en) * 2010-07-06 2013-08-22 Telefonaktiebolaget L M Ericsson (Publ) Self-Supporting Cable
US10381132B2 (en) * 2010-07-06 2019-08-13 Nkt Cables Group A/S Self-supporting cable
US20180190409A1 (en) * 2015-06-23 2018-07-05 Nkt Hv Cables Gmbh Electric Power Cable And A Process For The Production Of The Power Cable
US10679772B2 (en) * 2015-06-23 2020-06-09 Nkt Hv Cables Ab Electric power cable and a process for the production of the power cable
US20170352451A1 (en) * 2016-06-03 2017-12-07 AFC Cable Systems, Inc. Metal clad cable having parallel laid conductors
KR20180020550A (ko) * 2016-08-18 2018-02-28 엘에스전선 주식회사 전력 케이블

Also Published As

Publication number Publication date
IT1044874B (it) 1980-04-21
IE38504L (en) 1974-05-13
IE38504B1 (en) 1978-03-29
AU6241973A (en) 1975-05-15
AR196699A1 (es) 1974-02-12
ZA738653B (en) 1974-11-27
BR7308838D0 (pt) 1974-08-22
GB1395519A (en) 1975-05-29
JPS589521B2 (ja) 1983-02-21
JPS49124584A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-11-28
SE382519B (sv) 1976-02-02
CA994442A (en) 1976-08-03

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AS Assignment

Owner name: SOCIETA PIRELLI S.P.A., PIAZZALE CADORNA 5, 20123

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:INDUSTRIE PIRELLI S.P.A.;REEL/FRAME:003847/0084

Effective date: 19810101