US3726008A - Method for preparing an oil-filled cable having a corrugated sheath for cutting and cable so prepared - Google Patents

Method for preparing an oil-filled cable having a corrugated sheath for cutting and cable so prepared Download PDF

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Publication number
US3726008A
US3726008A US00180553A US3726008DA US3726008A US 3726008 A US3726008 A US 3726008A US 00180553 A US00180553 A US 00180553A US 3726008D A US3726008D A US 3726008DA US 3726008 A US3726008 A US 3726008A
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US
United States
Prior art keywords
sheath
oil
cable
cutting
insulation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00180553A
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English (en)
Inventor
V Buroni
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pirelli and C SpA
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Pirelli SpA
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Publication date
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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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Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G15/00—Cable fittings
    • H02G15/20—Cable fittings for cables filled with or surrounded by gas or oil
    • H02G15/26—Expansion vessels; Locking heads; Auxiliary pipe-lines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B9/00—Power cables
    • H01B9/06—Gas-pressure cables; Oil-pressure cables; Cables for use in conduits under fluid pressure
    • H01B9/0611—Oil-pressure cables
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G15/00—Cable fittings
    • H02G15/20—Cable fittings for cables filled with or surrounded by gas or oil
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49117—Conductor or circuit manufacturing
    • Y10T29/49194—Assembling elongated conductors, e.g., splicing, etc.
    • Y10T29/49195—Assembling elongated conductors, e.g., splicing, etc. with end-to-end orienting
    • Y10T29/49197—Assembling elongated conductors, e.g., splicing, etc. with end-to-end orienting including fluid evacuating or pressurizing

Definitions

  • a valve is secured to the support [58] Field of Search ..29/401, 628, 629, and is connected to a source of oil under pressure. 29/624; 156/47; 174/21, 24, 22 When the cable is cut, oil flowing out of the space between the sheath and the insulation is compensated [56] References Cited for, at least in part, by oil supplied through the valve.
  • the present invention relates to a method for preparing an oil-filled cable having a corrugated sheath, e.g., of aluminum, preliminary to the cutting of said sheath when end accessories are to be added or joints are to be built up.
  • a corrugated sheath e.g., of aluminum
  • the sheath of a cable must be cut.
  • the sheath is corrugated, its cutting can cause an oil outflow which will allow air penetration into the insulation.
  • the ideal condition would be to draw the corrugated sheath in such a way as to cause it to adhere to the insulation, so as to prevent an excessive oil outflow, but an aluminum sheath covering a cable core cannot be extruded closely on the latter.
  • it is necessary to leave a hollow space between the sheath and the insulation which acts both as a thermal insulating means and as a mechanical protective means.
  • Aluminum is a good heat-conductive material so that, if a hollow space were not left between the sheath and the core, the temperature which the sheath can reach in some working phases, as during extrusion, welding, etc., may be transferred, practically without reduction, to the conductor and would burn it.
  • aluminum is of low malleability, so that possible drawing operations, intended to cause the adhesion of the sheath to the insulation, would subject the latter, both during processing and during laying or service, to high mechanical stresses liable to damage it.
  • the present invention aims at obviating the above indicated disadvantages, by providing a method which permits preparation of the cable preliminary to the cutting of its sheath in such a way that said cutting operation can be carried out with the complete assurance that air penetration into the cable insulation does not take place.
  • the object of the invention is a method for preparing for cutting a corrugated aluminum sheath for the purpose of building up of accessories, characterized in that it comprises the steps of: drawing a portion of sheath on both sides of and including the cutting zone until the minimum hollow space between the sheath and the insulation which is consistent with the safety of the latter is obtained; puncturing said drawn portion of the sheath, while keeping the cable under pressure, in a position upstream that of the accessory to be fitted; applying an oil supply filling, such as a valve, to the puncture during the considerable oil outflow subsequent to the puncturing; and, supplying compensating oil through said valve for a period beginning before the sheath cutting and lasting as long as the opened section of the hollow space is exposed to air.
  • an oil supply filling such as a valve
  • a further object of the invention is a cable provided with an aluminum sheath, in which said sheath is prepared for cutting according to the above indicated method.
  • FIGURE of the accompanying sheet of drawing illustrates by a fragmentary, side elevation view, partly in section, one example of a cable prepared for cutting according to the method of the invention.
  • the drawing illustrates diagrammatically a core 11 of a cable 10, said core being constituted by at least one conductor surrounded by insulation or layers of insulation.
  • the core 11 is surrounded by a corrugated aluminum sheath 12.
  • the corrugated aluminum sheath 12 is drawn down for the whole length A, which includes the zone to be cut, and extends on both sides thereof.
  • the corrugated aluminum sheath 12 is drawn down for the whole length A, which includes the zone to be cut, and extends on both sides thereof.
  • the cable for the purpose of adding an accessory, it would be cut transversely of the length of the cable a portion thereof in the length A spaced from the left end thereof as viewed in the drawing.
  • the accessory is added in the direction of the arrow F with respect to the drawn portion.
  • the portion of drawn sheath forms with the cable core a hollow space 13, which preferably is of the order of l millimeter radially of the cable, so that the sheath will not engage the insulation throughout its periphery so that risk of damage to the latter is avoided.
  • a valve 15 is assembled with the sheath 12 upstream of the drawn portion A. Said valve 15, in the drawing, is applied on the top of corrugation l4, and such position is preferred.
  • the valve 15 comprises a support 16 provided with a central hole and welded to the sheath 12 at 17.
  • the valve body 18 is provided with a ball 19 acting as a shutter permitting flow of oil into, but not out of, the cable 10.
  • An annular gasket 20 is provided between the valve body 18 and the support 16, and a nozzle 21 has screw threads 22 engaging corresponding threads on support 16 and holds the valve body 18 in position.
  • valve 15 could be a manually operable valve.
  • the method for preparing the sheath to cutting comprises essentially the operations described hereinafter.
  • the sheath is first accurately drawn down, about the zone to be cut, along a length A so as to create, with respect to the core, a hollow space 13 which is the minimum consistent with the safety of the insulation and which, preferably, is of the order of l millimeter.
  • the drawing is carried out with known methods, for example, with a variable diameter jaw, which is gradually clamped down on the relevant portion and is slowly rotated about the cable axis to obtain a smooth surface.
  • the support 16 is secured on the sheath by means of welding 17 upstream of the drawn portion A, and a hotel is formed in the aluminum sheath corresponding to the hole in the support 16, acting with and the support, the ball 19, the gasket 20, the valve body 18 and the nozzle 21 are mounted and tightened on the support 16.
  • the nozzle 21 is then connected to an oil source, such as by the line 23 to a tank 24 containing oil under pressure, before carrying out the cut, the supply of oil being continued as long as the annular section, created in consequence of the sheath cut, remains open and exposed to air.
  • valve may be replaced by a threaded plug screwed into the support 16.
  • Method for preparing an oil-filled cable for cutting transversely of its length at a predetermined cutting zone said cable havinga core comprising a conductor surrounded by insulation and having a corrugated sheath around said insulation, said method comprising drawing down said sheath at said cutting zone and on both sides thereof to reduce the spacing between said sheath and said insulation at said cutting zone and to thereby reduce the oil flow passageway between said sheath and said insulation, puncturing said sheath at a portion thereof at one side of said zone while maintaining the oil under pressure at said portion whereby oil flows out of the aperture produced by puncturing and thereafter stopping the flow of oil from said aperture with a fitting permitting the subsequent supply of oil under pressure to said aperture from exteriorly of said sheath.

Landscapes

  • Processing Of Terminals (AREA)
  • Gas Or Oil Filled Cable Accessories (AREA)
US00180553A 1970-09-17 1971-09-15 Method for preparing an oil-filled cable having a corrugated sheath for cutting and cable so prepared Expired - Lifetime US3726008A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT2982270 1970-09-17

Publications (1)

Publication Number Publication Date
US3726008A true US3726008A (en) 1973-04-10

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ID=11228503

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Application Number Title Priority Date Filing Date
US00180553A Expired - Lifetime US3726008A (en) 1970-09-17 1971-09-15 Method for preparing an oil-filled cable having a corrugated sheath for cutting and cable so prepared

Country Status (7)

Country Link
US (1) US3726008A (cg-RX-API-DMAC10.html)
AU (1) AU3353971A (cg-RX-API-DMAC10.html)
BE (1) BE772720A (cg-RX-API-DMAC10.html)
DE (1) DE2145527A1 (cg-RX-API-DMAC10.html)
FR (1) FR2106583A1 (cg-RX-API-DMAC10.html)
GB (1) GB1299820A (cg-RX-API-DMAC10.html)
ZA (1) ZA716125B (cg-RX-API-DMAC10.html)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170314692A1 (en) * 2016-04-28 2017-11-02 Novinium, Inc. Injection electrical connector
CN115940077A (zh) * 2022-09-27 2023-04-07 中国南方电网有限责任公司超高压输电公司广州局 海底充油电缆中间接头渗油点的封堵装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1744887A (en) * 1928-12-01 1930-01-28 American Telephone & Telegraph Device for introducing gas into cables
US2053163A (en) * 1930-08-18 1936-09-01 Gen Electric Joint for fluid filled cables and method of making the same
US2089052A (en) * 1929-01-16 1937-08-03 Gen Electric High tension cable system
US2321731A (en) * 1941-12-18 1943-06-15 Bell Telephone Labor Inc Method of making repairs and joints in cable sheaths

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1744887A (en) * 1928-12-01 1930-01-28 American Telephone & Telegraph Device for introducing gas into cables
US2089052A (en) * 1929-01-16 1937-08-03 Gen Electric High tension cable system
US2053163A (en) * 1930-08-18 1936-09-01 Gen Electric Joint for fluid filled cables and method of making the same
US2321731A (en) * 1941-12-18 1943-06-15 Bell Telephone Labor Inc Method of making repairs and joints in cable sheaths

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170314692A1 (en) * 2016-04-28 2017-11-02 Novinium, Inc. Injection electrical connector
US10199805B2 (en) 2016-04-28 2019-02-05 Novinium, Inc. Injection electrical connector
US10230222B2 (en) 2016-04-28 2019-03-12 Novinium, Inc. Injection electrical connector
US10418794B2 (en) * 2016-04-28 2019-09-17 Novinium, Inc. Injection electrical connector
US10522984B2 (en) 2016-04-28 2019-12-31 Novinium, Inc. Injection electrical connector
US10522983B2 (en) 2016-04-28 2019-12-31 Novinium, Inc. Injection electrical connector
US10840678B2 (en) 2016-04-28 2020-11-17 Novinium, Inc. Injection electrical connector
CN115940077A (zh) * 2022-09-27 2023-04-07 中国南方电网有限责任公司超高压输电公司广州局 海底充油电缆中间接头渗油点的封堵装置

Also Published As

Publication number Publication date
ZA716125B (en) 1972-05-31
BE772720A (fr) 1972-01-17
DE2145527A1 (de) 1972-04-20
FR2106583A1 (cg-RX-API-DMAC10.html) 1972-05-05
AU3353971A (en) 1973-03-22
GB1299820A (en) 1972-12-13

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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