EP0422306B1 - Communication cable - Google Patents

Communication cable Download PDF

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Publication number
EP0422306B1
EP0422306B1 EP89402777A EP89402777A EP0422306B1 EP 0422306 B1 EP0422306 B1 EP 0422306B1 EP 89402777 A EP89402777 A EP 89402777A EP 89402777 A EP89402777 A EP 89402777A EP 0422306 B1 EP0422306 B1 EP 0422306B1
Authority
EP
European Patent Office
Prior art keywords
communication cable
intermediate layer
cable according
layer
polyethylene
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
EP89402777A
Other languages
German (de)
French (fr)
Other versions
EP0422306A1 (en
Inventor
Kjell Eldensjo
Jörgen Persson
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.)
Nexans IKO Sweden AB
Original Assignee
Iko Kabel AB
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 Iko Kabel AB filed Critical Iko Kabel AB
Priority to AT89402777T priority Critical patent/ATE130697T1/en
Priority to DE68924915T priority patent/DE68924915T2/en
Publication of EP0422306A1 publication Critical patent/EP0422306A1/en
Application granted granted Critical
Publication of EP0422306B1 publication Critical patent/EP0422306B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/28—Protection against damage caused by moisture, corrosion, chemical attack or weather
    • H01B7/282—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable
    • 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
    • H01B11/1058—Screens specially adapted for reducing interference from external sources using a coating, e.g. a loaded polymer, ink or print
    • H01B11/1066—Screens specially adapted for reducing interference from external sources using a coating, e.g. a loaded polymer, ink or print the coating containing conductive or semiconductive material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/18—Protection against damage caused by wear, mechanical force or pressure; Sheaths; Armouring
    • H01B7/187—Sheaths comprising extruded non-metallic layers

Definitions

  • the present invention relates to a thin communication cable which is non-sensitive to moisture from an electrical point of view.
  • a communication cable is especially intended for use in frequencies up to and including the MHz-region.
  • the cable is provided with at least two electric conductors and a surrounding sheath.
  • a conventional field thin cable including one, two, or more, pairs of insulated communication wires intended for use at frequencies up to and including the MHz-region, with surrounding sheath, can get an electric line attenuation increase of more than 100% at for instance drizzle at the frequency 1.024 MHz which is considerably more than previously used frequencies.
  • the purpose of the invention is therefore in the first place to provide a communication cable, the electric line attenuation of which holds a low and continuous level also when the cable is subjected to moisture or varying external environment with respect to the weather conditions when using one and the same frequency.
  • the sheath is composed of three different, mutually combined layers - an internal layer, an external layer and an intermediate layer - and that the intermediate layer consists of a semiconductor material.
  • Said electrical line attenuation can be of the magnitude ⁇ 14 dB/km at 1.024 MHz.
  • the Fig. shown on the enclosed drawing discloses a section of a communication cable which is formed according to the principles of the invention.
  • the communication cable 10 in said Fig. is a so-called two-wire-cable but the invention can, of course, be applicable to a cable with two or more pairs of wires.
  • the communication cable comprises two similar separate electric conductors 12, each consisting of a polyethylene insulated tinned copper wire 14.
  • the cable also comprises two tension relieve elements 16, which in this case each consists of a polyethylene insulated stainless steel wire 18.
  • the two insulated conductors 12 and the two insulated steel wires 16 are twisted to a compact quad in a manner known per se.
  • the wires 16 and the conductors 12 are surrounded by a sheath which has been fill extruded around the whole quad.
  • the sheath is composed of three different mutually combined layers.
  • the layers consist of plastic, preferably polyethylene.
  • the internal layer 20 and the external layer 22 are non-conducting but the intermediate layer 24 is semi-conducting.
  • the assembly has been made by melting the three layers in one single moment but, of course, the use of glue or some other assembly method may be imagined.
  • the internal layer 20 of polyethylene can have a low density, whilst the external layer 22 shall consist of a durable plastic with a high density or another durable plastic, for instance polyamide.
  • the intermediate layer 24 should have a volume resistivity suitable for the line attenuation level, preferably of the magnitude 102 ⁇ cm, at at temperature of 20°. For the purpose intended it is suitable that the internal layer 20 is between four and six times thicker than the intermediate layer 24.
  • the sheath on the whole must be proportionately thin, for the exemplified two-wire-cable about 0.6 mm, in which case the intermediate layer 24 should have a thickness ⁇ 0.10 mm.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Insulated Conductors (AREA)
  • Communication Cables (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Laminated Bodies (AREA)

Description

    COMMUNICATION CABLE
  • The present invention relates to a thin communication cable which is non-sensitive to moisture from an electrical point of view. A communication cable is especially intended for use in frequencies up to and including the MHz-region. The cable is provided with at least two electric conductors and a surrounding sheath.
  • It has been shown that a conventional field thin cable including one, two, or more, pairs of insulated communication wires intended for use at frequencies up to and including the MHz-region, with surrounding sheath, can get an electric line attenuation increase of more than 100% at for instance drizzle at the frequency 1.024 MHz which is considerably more than previously used frequencies. The purpose of the invention is therefore in the first place to provide a communication cable, the electric line attenuation of which holds a low and continuous level also when the cable is subjected to moisture or varying external environment with respect to the weather conditions when using one and the same frequency. This is provided in connection with a communication cable of small diameter of the kind mentioned in the introductory portion first of all thereby that the sheath is composed of three different, mutually combined layers - an internal layer, an external layer and an intermediate layer - and that the intermediate layer consists of a semiconductor material. Said electrical line attenuation can be of the magnitude ≦ 14 dB/km at 1.024 MHz.
  • Further advantages and characterizing features concerning the new communication cable are apparent from the following description and from the claims.
  • The Fig. shown on the enclosed drawing discloses a section of a communication cable which is formed according to the principles of the invention.
  • The communication cable 10 in said Fig. is a so-called two-wire-cable but the invention can, of course, be applicable to a cable with two or more pairs of wires. The communication cable comprises two similar separate electric conductors 12, each consisting of a polyethylene insulated tinned copper wire 14. Moreover, the cable also comprises two tension relieve elements 16, which in this case each consists of a polyethylene insulated stainless steel wire 18. The two insulated conductors 12 and the two insulated steel wires 16 are twisted to a compact quad in a manner known per se. The wires 16 and the conductors 12 are surrounded by a sheath which has been fill extruded around the whole quad.
  • As is apparent from the Fig. of the drawing the sheath is composed of three different mutually combined layers. The layers consist of plastic, preferably polyethylene. The internal layer 20 and the external layer 22 are non-conducting but the intermediate layer 24 is semi-conducting.
  • The assembly has been made by melting the three layers in one single moment but, of course, the use of glue or some other assembly method may be imagined.
  • The internal layer 20 of polyethylene can have a low density, whilst the external layer 22 shall consist of a durable plastic with a high density or another durable plastic, for instance polyamide. The intermediate layer 24 should have a volume resistivity suitable for the line attenuation level, preferably of the magnitude 10²Ωcm, at at temperature of 20°. For the purpose intended it is suitable that the internal layer 20 is between four and six times thicker than the intermediate layer 24.
  • It should be noticed that the sheath on the whole must be proportionately thin, for the exemplified two-wire-cable about 0.6 mm, in which case the intermediate layer 24 should have a thickness ≦ 0.10 mm.
  • A communication cable of the kind stated above which has an external diameter of nominally 4.7 mm, gives a line attenuation of 12.8 ± 0.5 dB/km at the temperature 20°C, irrespective of the outer weather conditions.

Claims (7)

  1. A thin communication cable (10), including one, two, or more, pairs of insulated communication wires for use at frequencies up to and including the MHz-region, with surrounding sheath (20,22,24) characterized in that the sheath is composed of three different mutually combined layers - one internal insulating layer (20), one external insulating layer (22) and one intermediate layer (24) - and in that the intermediate layer (24) consists of a semiconductor material, so that the cable, as for electrical signal transmission, is non-sensitive to moisture.
  2. Communication cable according to claim 1, characterized in that the layers (20, 22, 24) consist of plastic.
  3. Communication cable according to claim 1 or 2, characterized that the three layers (20,22,24) are joined by melting at extrusion in one single step.
  4. Communication cable according to any of claims 1-3, characterized in that the internal layer (20) consists of polyethylene with a low density, that the external layer (23) consists of polyethylene with a high density or of polyamide and that the intermediate layer (24) consists of semiconductive polyethylene.
  5. Communication cable according to claim 4, characterized in that the volume resistivity of the intermediate layer (24) is of the magnitude 10²Ω cm.
  6. Communication cable according to any of claims 1-5, characterized in that the internal layer (20) is between 4 and 6 times the thickness of the intermediate layer (24).
  7. Communication cable according to claim 2, characterized in that the layers (20, 22, 24) consist of polyethylene.
EP89402777A 1988-09-06 1989-10-09 Communication cable Expired - Lifetime EP0422306B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AT89402777T ATE130697T1 (en) 1989-10-09 1989-10-09 NEWS CABLE.
DE68924915T DE68924915T2 (en) 1989-10-09 1989-10-09 Communication cable.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE8803126A SE468871B (en) 1988-09-06 1988-09-06 SMALL COMMUNICATION CABLE INTENDED FOR FREQUENCY UP TO AND WITH THE MHZ AREA

Publications (2)

Publication Number Publication Date
EP0422306A1 EP0422306A1 (en) 1991-04-17
EP0422306B1 true EP0422306B1 (en) 1995-11-22

Family

ID=20373236

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89402777A Expired - Lifetime EP0422306B1 (en) 1988-09-06 1989-10-09 Communication cable

Country Status (6)

Country Link
EP (1) EP0422306B1 (en)
AU (1) AU620131B2 (en)
DK (1) DK169932B1 (en)
FI (1) FI95419C (en)
NO (1) NO176458C (en)
SE (1) SE468871B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2712115A1 (en) * 1993-11-05 1995-05-12 Filotex Sa Screened cable, having a low level of noise and a high service temperature
AU5191801A (en) 2001-06-14 2002-12-19 Pirelli Cables Australia Limited Communications cable provided with a crosstalk barrier for use at high transmission frequencies

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3668298A (en) * 1969-12-10 1972-06-06 Bell Telephone Labor Inc Multiconductor communications cable
WO1988006741A1 (en) * 1987-03-03 1988-09-07 Union Carbide Benelux N.V. Cable containing water-blocking material

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NO140249C (en) * 1977-04-28 1979-07-25 Elektrisitetsforsyning STRONG CURRENT CABLE WHICH IS RESISTANT TO THE FORMATION OF WATER TREES IN THE INSULATION AND PROCEDURE FOR THE MANUFACTURE OF SUCH CABLE
US4486252A (en) * 1980-10-08 1984-12-04 Raychem Corporation Method for making a low noise cable

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3668298A (en) * 1969-12-10 1972-06-06 Bell Telephone Labor Inc Multiconductor communications cable
WO1988006741A1 (en) * 1987-03-03 1988-09-07 Union Carbide Benelux N.V. Cable containing water-blocking material

Also Published As

Publication number Publication date
AU4015289A (en) 1990-03-15
DK437789A (en) 1990-03-07
EP0422306A1 (en) 1991-04-17
SE8803126D0 (en) 1988-09-06
NO893402D0 (en) 1989-08-24
FI894129A (en) 1990-03-07
DK169932B1 (en) 1995-04-03
DK437789D0 (en) 1989-09-05
AU620131B2 (en) 1992-02-13
NO176458B (en) 1994-12-27
FI894129A0 (en) 1989-09-01
FI95419B (en) 1995-10-13
SE8803126L (en) 1990-03-07
FI95419C (en) 1996-01-25
NO176458C (en) 1995-04-05
NO893402L (en) 1990-03-07
SE468871B (en) 1993-03-29

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