GB2118355A - Electric cable - Google Patents

Electric cable Download PDF

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Publication number
GB2118355A
GB2118355A GB08307618A GB8307618A GB2118355A GB 2118355 A GB2118355 A GB 2118355A GB 08307618 A GB08307618 A GB 08307618A GB 8307618 A GB8307618 A GB 8307618A GB 2118355 A GB2118355 A GB 2118355A
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GB
United Kingdom
Prior art keywords
conductor
metal
electric
tape
conductors
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.)
Withdrawn
Application number
GB08307618A
Other versions
GB8307618D0 (en
Inventor
Peter Alfred Brinsley
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.)
Balfour Beatty PLC
Original Assignee
BICC PLC
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by BICC PLC filed Critical BICC PLC
Priority to GB08307618A priority Critical patent/GB2118355A/en
Publication of GB8307618D0 publication Critical patent/GB8307618D0/en
Publication of GB2118355A publication Critical patent/GB2118355A/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B11/00—Communication cables or conductors
    • H01B11/02—Cables with twisted pairs or quads
    • H01B11/06—Cables with twisted pairs or quads with means for reducing effects of electromagnetic or electrostatic disturbances, e.g. screens
    • H01B11/10—Screens specially adapted for reducing interference from external sources
    • H01B11/1016—Screens specially adapted for reducing interference from external sources composed of a longitudinal lapped tape-conductor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B11/00—Communication cables or conductors
    • H01B11/18—Coaxial cables; Analogous cables having more than one inner conductor within a common outer conductor
    • H01B11/1808—Construction of the conductors
    • H01B11/183—Co-axial cables with at least one helicoidally wound tape-conductor

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Insulated Conductors (AREA)

Abstract

An electric cable comprises at least one elongate insulated electric conductor and an outer electric screening layer comprising at least one expanded sheet of metal or metal alloy of high electrical conductivity, which sheet at least partially surrounds the conductor or assembly of conductors. Preferably, the screening layer is formed by applying longitudinally to and transversely folding around the conductor or assembly of conductors an expanded tape of copper, aluminium or alloys thereof. The longitudinal edge of the folded tape is bent over to prevent damage to the conductor insulation. Alternatively the screening layer may be applied helically. The layer may be spaced from the conductor by insulating discs or a helically wound insulator. A continuous layer of insulating material may be used.

Description

SPECIFICATION Electric cable This invention relates to an electric cable comprising at least one elongate electric conductor which is electrically insulated with respect to a surrounding electric screening layer.
The electric screening layer of a cable is usually made from braided metal wire, or a metal tape laid longitudinally along and transversely folded around, or wound helically about, the conductor or conductors. Electric screening layers either completely surround the conductor or conductors to prevent transmission and/or reception of interference signals, or partially surround the conductor or conductors to allow transmission and/or reception of signals of a predetermined frequency (for example, in "leaky" coaxial cables).
According to the present invention, an improved electric cable comprises at least one elongate electric conductor which is electrically insulated with respect to an outer electric screening layer, wherein the electric screening layer comprises an expanded sheet of metal or metal alloy of high electrical conductivity, which sheet at least partially surrounds the conductor or assembly of conductors.
By an expanded sheet of metal or metal alloy is meant a network of metal or metal alloyformed by stamping or cutting a sheet of metal or metal alloy and stretching the metal or metal alloy of the sheet to form openings in the sheet without the removal of any metal or metal alloy.
Preferably, the expanded sheet is of copper or copper alloy or of aluminium or aluminium alloy.
Where the exanded sheet is of copper or copper alloy, preferably the overall thickness of the sheet lies in the range 0.075 to 0.3 mm, the width of copper or copper alloy between each hole lies in the range 0.1 to 0.8 mm and the area of each hole lies in the range 2 to 6 sq. mm.
Where the electric cable is a coaxial cable, the inner conductor may have a continuous layer of electrically insulating material, the insulating layer spacing the electric screening layer from the inner conductor, or, in all cases, the electric screening layer may be spaced from the inner conductor by longitudinally spaced discs of electrically insulating material or by a helical membrane of electrically insulating material fitted on or around the inner conductor.
Preferably, the expanded sheet of metal or metal alloy of high electrical conductivity completely surrounds the conductor or assembly of conductors.
The expanded sheet of metal or metal alloy of high electrical conductivity is preferably in the form of a tape which is applied lengthwise to and folded transversely around the conductor or assembly of conductors. Alternatively, the tape may be wound helicaaly around the conductor or assembly of conductors.In both cases, to reduce risk of damage to the conductor insulation and of a possible consequential electrical fault, preferably each longitudinally extending edge of the expanded tape of metal or metal alloy of high electrical conductivity is maintained out of contact with the insulation of the conductor or conductors by folding å longitudinally extending marginal portion of the tape adjacent at least one longitudinally extending edge outwardly and over the outer face of the tape and by folding the tape transversely, or lapping the tape helically, around the conductor or assembly of conductors with an overlap, the folded longitudinally extending marginal portion of the tape underlying the outer longitudinally extending edge of the tape at the overlap.
Four examples of expanded sheets of metal or metal alloy suitable for use in the manufacture of an electric screening layer of an electric cable will now be given.
Example I An expanded sheet of copper having: Overall thickness = 0.075 mm.
Width of copper between adjacent holes = 0.8 mm.
Diamond-shaped holes, each of area = 3 sq. mm.
Example II An expanded sheet of copper having: Overall thickness = 0.300 mm.
Width of copper between adjacent holes = 0.3 mm.
Diamond-shaped holes, each of area = 6 sq. mm.
Example III An expanded sheet of aluminium having: Overall thickness = 0.200 mm.
Width of aluminium between adjacent holes = 0.65 mm.
Diamond-shaped holes, each of area = 3 sq. mm.
Example IV An expanded sheet of aluminium having: Overall thickness = 0.127 mm.
Width of aluminium between adjacent holes = 0.127 mm.
Diamond-shaped holes, each of area = 2 sq. mm.
1. An electric cable comprising at least one elongate electric conductor which is electrically insulated with respect to an outer electric screening layer, wherein the electric screening layer comprises an expanded sheet of metal or metal alloy of high electrical conductivity, which sheet at least partially surrounds the conductor or assembly of conductors.
2. An electric cable as claimed in Claim 1, wherein the expanded sheet is of copper or copper alloy or of aluminium or aluminium alloy.
3. An electric cable as claimed in Claim 1 or 2, wherein the expanded sheet of metal or metal alloy completely surrounds the conductor or assembly of conductors.
4. An electric cable as claimed in any one of the preceding Claims which has a single inner conductor, wherein the inner conductor has a continuous
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Electric cable This invention relates to an electric cable comprising at least one elongate electric conductor which is electrically insulated with respect to a surrounding electric screening layer. The electric screening layer of a cable is usually made from braided metal wire, or a metal tape laid longitudinally along and transversely folded around, or wound helically about, the conductor or conductors. Electric screening layers either completely surround the conductor or conductors to prevent transmission and/or reception of interference signals, or partially surround the conductor or conductors to allow transmission and/or reception of signals of a predetermined frequency (for example, in "leaky" coaxial cables). According to the present invention, an improved electric cable comprises at least one elongate electric conductor which is electrically insulated with respect to an outer electric screening layer, wherein the electric screening layer comprises an expanded sheet of metal or metal alloy of high electrical conductivity, which sheet at least partially surrounds the conductor or assembly of conductors. By an expanded sheet of metal or metal alloy is meant a network of metal or metal alloyformed by stamping or cutting a sheet of metal or metal alloy and stretching the metal or metal alloy of the sheet to form openings in the sheet without the removal of any metal or metal alloy. Preferably, the expanded sheet is of copper or copper alloy or of aluminium or aluminium alloy. Where the exanded sheet is of copper or copper alloy, preferably the overall thickness of the sheet lies in the range 0.075 to 0.3 mm, the width of copper or copper alloy between each hole lies in the range 0.1 to 0.8 mm and the area of each hole lies in the range 2 to 6 sq. mm. Where the electric cable is a coaxial cable, the inner conductor may have a continuous layer of electrically insulating material, the insulating layer spacing the electric screening layer from the inner conductor, or, in all cases, the electric screening layer may be spaced from the inner conductor by longitudinally spaced discs of electrically insulating material or by a helical membrane of electrically insulating material fitted on or around the inner conductor. Preferably, the expanded sheet of metal or metal alloy of high electrical conductivity completely surrounds the conductor or assembly of conductors. The expanded sheet of metal or metal alloy of high electrical conductivity is preferably in the form of a tape which is applied lengthwise to and folded transversely around the conductor or assembly of conductors. Alternatively, the tape may be wound helicaaly around the conductor or assembly of conductors.In both cases, to reduce risk of damage to the conductor insulation and of a possible consequential electrical fault, preferably each longitudinally extending edge of the expanded tape of metal or metal alloy of high electrical conductivity is maintained out of contact with the insulation of the conductor or conductors by folding å longitudinally extending marginal portion of the tape adjacent at least one longitudinally extending edge outwardly and over the outer face of the tape and by folding the tape transversely, or lapping the tape helically, around the conductor or assembly of conductors with an overlap, the folded longitudinally extending marginal portion of the tape underlying the outer longitudinally extending edge of the tape at the overlap. Four examples of expanded sheets of metal or metal alloy suitable for use in the manufacture of an electric screening layer of an electric cable will now be given. Example I An expanded sheet of copper having: Overall thickness = 0.075 mm. Width of copper between adjacent holes = 0.8 mm. Diamond-shaped holes, each of area = 3 sq. mm. Example II An expanded sheet of copper having: Overall thickness = 0.300 mm. Width of copper between adjacent holes = 0.3 mm. Diamond-shaped holes, each of area = 6 sq. mm. Example III An expanded sheet of aluminium having: Overall thickness = 0.200 mm. Width of aluminium between adjacent holes = 0.65 mm. Diamond-shaped holes, each of area = 3 sq. mm. Example IV An expanded sheet of aluminium having: Overall thickness = 0.127 mm. Width of aluminium between adjacent holes = 0.127 mm. Diamond-shaped holes, each of area = 2 sq. mm. CLAIMS
1. An electric cable comprising at least one elongate electric conductor which is electrically insulated with respect to an outer electric screening layer, wherein the electric screening layer comprises an expanded sheet of metal or metal alloy of high electrical conductivity, which sheet at least partially surrounds the conductor or assembly of conductors.
2. An electric cable as claimed in Claim 1, wherein the expanded sheet is of copper or copper alloy or of aluminium or aluminium alloy.
3. An electric cable as claimed in Claim 1 or 2, wherein the expanded sheet of metal or metal alloy completely surrounds the conductor or assembly of conductors.
4. An electric cable as claimed in any one of the preceding Claims which has a single inner conductor, wherein the inner conductor has a continuous layer of electrically insulating material, the insulating layer spacing the electric screening layer from the inner conductor.
5. An electric cable as claimed in any one of Claims 1 to 3 which has a single inner conductor, wherein the electric screening layer is spaced from the inner conductor by longitudinally spaced discs of electrically insulating material or by a helical membrane of electrically insulating material fitted on or around the inner conductor.
6. An electric cable as claimed in any one of the preceding Claims, wherein the expanded sheet of metal or metal alloy is in the form of a tape which is applied lengthwise to and folded transversely around the conductor or assembly of conductors.
7. An electric cable as claimed in any one of Claims 1 to 5, wherein the expanded sheet of metal or metal alloy is in the form of a tape which is lapped helically around the conductor or assembly of conductors.
8. An electric cable as claimed in Claim 6 or 7, wherein each longitudinally extending edge of the tape of expanded metal or metal aHoy is maintained out of contact with the insulation of the conductor or conductors by folding a longitudinally extending marginal portion of the tape adjacent at least one longitudinally extending edge outwardly and over the outer face of the tape and by folding the tape transversely, or lapping the tape helically, around the conductor or assembly of conductors with an overlap, the folded longitudinally extending marginal portion of the tape underlying the other longitudinally extending edge of the tape at the overlap.
9. An electric cable comprising at least one elongate electric conductor which is electrically insulated with respect to an outer electric screening layer, wherein the electric screening layer comprises an expanded sheet of metal or metal alloy in accordance with any one of Examples I to IV.
GB08307618A 1982-03-18 1983-03-18 Electric cable Withdrawn GB2118355A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08307618A GB2118355A (en) 1982-03-18 1983-03-18 Electric cable

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8207992 1982-03-18
GB08307618A GB2118355A (en) 1982-03-18 1983-03-18 Electric cable

Publications (2)

Publication Number Publication Date
GB8307618D0 GB8307618D0 (en) 1983-04-27
GB2118355A true GB2118355A (en) 1983-10-26

Family

ID=26282293

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08307618A Withdrawn GB2118355A (en) 1982-03-18 1983-03-18 Electric cable

Country Status (1)

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GB (1) GB2118355A (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1288924A (en) * 1968-11-14 1972-09-13
GB1387991A (en) * 1971-01-22 1975-03-19 Post Office Electric cables
US3917900A (en) * 1971-07-26 1975-11-04 Anaconda Co Electric cable with expanded-metal shield and method of making

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1288924A (en) * 1968-11-14 1972-09-13
GB1387991A (en) * 1971-01-22 1975-03-19 Post Office Electric cables
US3917900A (en) * 1971-07-26 1975-11-04 Anaconda Co Electric cable with expanded-metal shield and method of making

Also Published As

Publication number Publication date
GB8307618D0 (en) 1983-04-27

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)