USRE27181E - Manufacture of oil-filled electric cables - Google Patents

Manufacture of oil-filled electric cables Download PDF

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Publication number
USRE27181E
USRE27181E US1374070A USRE27181E US RE27181 E USRE27181 E US RE27181E US 1374070 A US1374070 A US 1374070A US RE27181 E USRE27181 E US RE27181E
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US
United States
Prior art keywords
sheath
plug
vacuum
guard
oil
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
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English (en)
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Prysmian Cables and Systems Ltd
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Publication date
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Publication of USRE27181E publication Critical patent/USRE27181E/en
Assigned to PIRELLI GENERAL PLC., A PUBLIC LIMITED COMPANY reassignment PIRELLI GENERAL PLC., A PUBLIC LIMITED COMPANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: PIRELLI UK PLC.
Expired 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
    • H02G1/00—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines
    • H02G1/14—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines for joining or terminating cables
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • H01B13/30—Drying; Impregnating

Definitions

  • FIG. 3 MANUFNCTURE OF OIL-FILLED ELECTRIC CABLES Original Filed Nov. 5, 1965 FIG! FIG. 3
  • ABSTRACT OF THE DISCLOSURE This invention relates to the manufacture of oil-filled electric cables and more particularly to the manufacture of such cables by the postor vacuum-impregnation technique described in .[copending United States application Ser. No. 307,486] United States Pat. No. 3,444,016.
  • the plug disclosed in [application No. 307,486] Pat. No. 3,444,016 includes a pair of O-rings for providing a seal between the cylindrical surface of the plug and the interior surface of the sheath, the O-rings fitting into circumferential grooves in the plug surface and being made of a suitable resilient material. Between the pair of 0- rings is provided a vacuum guard-ring, an internal passageway extending longitudinally within the plug from the guard-ring to another aperture onto which a vacuum source can be applied. This aperture is located in the forward end of the plug beyond the sheath termination. Thus any air penetrating past the forward O-ring is removed before it can reach the main body of the evacuated sheathed cable.
  • a similar plug can be used at the trailing end of the cable.
  • the construction of the plug is an important feature of the post-impregnation technique.
  • the plug contains a further valved longitudinal bore through which the impregnating oil can be subsequently introduced into the evacuated core.
  • a common feature of all the plug designs suggested to date is the use of a pair of O-rings with intermediate vacuum guard-ring. Equally well, it is important to simplify the design of the plug and to render it as far as possible useful with a range of cable sizes.
  • the present invention is accordingly directed to an improved vacuum guard system of universal application; and to this end it provides for any air leaking past the forward O-ring to be withdrawn from the guard-ring through the Wall of the sheath rat-her than through the plug.
  • the present invention therefore provides a method of preventing ingress of air into an evacuated system comprising a sheathed cable core closed by an end plug surrounded by the sheath and including a vacuum guard ring, the method comprising the steps of forming an aperture in the wall of the sheath adjacent the vacuum guard ring connecting a vacuum line to the guard ring through the aperture and sealing the sheath around the inserted line.
  • Apparatus provided by the present invention for carrying out this method may comprise a shield through which the vacuum line passes, a packing element shaped to conform with the sheath contour and means for clamping the shield to the sheath with the packing element interposed inbetween.
  • the clamping means consists of one or more metallic bands which extend around the sheath, each band including a tensioning device whereby a tight grip can be provided by adjustment of the total band length. Such tensioning device also enables the apparatus to be used for cables of varying sizes.
  • clamping means are Well-known jubilee or invicta clips.
  • the shield be in the form of a metal plate shaped to conform with the sheath contour with a packing element of uniform thickness composed of flexible rubbery material which will automatically adopt the sheath contour when the plate is clamped into position.
  • the vacuum line passes through both the plate, being securely fixed thereto as by welding, and the packing element, protruding from the latter just sufficiently to engage the aperture in the sheath.
  • the aperture in the sheath is made by any convenient means "depending on the material of the sheath, usually lead or aluminium, once the plug is in situ.
  • the vacuum line is in the form of hypodermic needle slidable within the shield, with a solid tip and longitudinal bore terminating in a side-opening near the tip.
  • the needle itself forms the aperture in the sheath, the side-opening being sufficiently near the tip so as to be positioned within the guard-ring once the needle has penetrated.
  • FIG. 1 represents a side-view of a sheathed cable with vacuum guard apparatus secured thereto;
  • FIG. 2 represents a transverse cross-sectional view through the sheathed cable, in the direction II of FIG. 1;
  • FIG. 3 represents a longitudinal cross-sectional view through the sheathed cable of FIG. 1.
  • an evacuated system comprising a cable core 1 secured to an end-plug 3 with both core and plug surrounded by a lead sheath 2 applied by extrusion in the normal manner.
  • hawser 4 for pulling the cable core through the extrusion press and supplying heating current for drying purposes in the known manner.
  • Plug 3 includes a circumferential vacuum guard-ring 12 and, located on either side of the guard-ring, pairs of O-rings '6 housed in circumferential grooves 5.
  • Vacuum line 9 leading to vacuum pump (not shown) s soldered or otherwise jointed to curved metal plate 7 :onstituting a shield, the line passing through the plate 1nd protruding suificiently on the concave side thereof pass through aperture 14 in the sheath wall into the guard-ring 12.
  • both the jacking 8 and plate 7 conform to the sheath contour to issist the formation of a tight seal between the vacuum ine andthe sheath wall.
  • Plate 7 is clamped to the sheath by metal bands 10 ensioned by screws 13 in the manner of a jubilee :lip.
  • a further rubber packing 11 is interposed between he bands and the sheath around the remainder of its :ircumference not straddled by plate 7, in order to avoid iamaging the lead sheath (lead being a relatively soft naterial) on tightening of the clips.
  • Apparatus for preventing ingress of air into an :vacuated system which includes a cable core that is secured to an end plug wherein both said core and said and plug are surrounded by a sheath
  • the apparatus comprising a vacuum guard ring, vacuum line means adapted for 'fiuid communication with said vacuum guard ring, shield means through which said vacuum line means is passed, said shield means and said vacuum line means having sealing means interposed therebetween to provide a vacuum-tight seal between said vacuum line means and said shield means, and means for clamping the shield means to said sheath means, said shield means and sheath means having packing means interposed therebetween which packing means is shaped to conform to the contour of said sheath means.
  • clamping means includes at least one metallic band means extending around said sheath means, said band means additionally comprising tensioning means which enables the adjustment of the length of said band means whereby a tight fit may be achieved.
  • the apparatus of claim 1 additionally comprising means for forming an aperture in the wall of said sheath.
  • the vacuum line means includes a solid tip capable of puncturing said sheath and slidable within said shield means, said vacuum line means further including a side opening therein, said side opening being positioned so as to be in communication with said guard-ring one said sheath means has been punctured by said solid tip means.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Cable Accessories (AREA)
  • Gas Or Oil Filled Cable Accessories (AREA)
US1374070 1964-11-05 1970-02-24 Manufacture of oil-filled electric cables Expired USRE27181E (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB45115/64A GB1106895A (en) 1964-11-05 1964-11-05 Improvements in or relating to the manufacture of oil-filled electric cables

Publications (1)

Publication Number Publication Date
USRE27181E true USRE27181E (en) 1971-09-21

Family

ID=10435943

Family Applications (1)

Application Number Title Priority Date Filing Date
US1374070 Expired USRE27181E (en) 1964-11-05 1970-02-24 Manufacture of oil-filled electric cables

Country Status (5)

Country Link
US (1) USRE27181E (de)
BR (1) BR6574231D0 (de)
DE (1) DE1540303B1 (de)
ES (1) ES319610A1 (de)
GB (1) GB1106895A (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3564119A (en) * 1969-11-24 1971-02-16 John T Thompson Pressure-equalizing accessory for cables
DE3627600C3 (de) * 1986-08-14 1997-11-20 Kabel & Draht Gmbh Verfahren und Vorrichtung zum Regenerieren von Starkstromkabeln

Also Published As

Publication number Publication date
DE1540303B1 (de) 1969-12-04
GB1106895A (en) 1968-03-20
ES319610A1 (es) 1966-08-01
BR6574231D0 (pt) 1973-05-29

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Legal Events

Date Code Title Description
AS Assignment

Owner name: PIRELLI GENERAL PLC., A PUBLIC LIMITED COMPANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:PIRELLI UK PLC.;REEL/FRAME:004236/0903

Effective date: 19831206