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US4342880A Expired / Lapsed US ⏱️ 0.0 years remaining

Electric cable for medium voltage

Assignee: Pirelli and C SpA
•
Filing: 1980-08-20
•
Granted: 1982-08-03
•
Expires: 2000-08-20
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Abstract

Abstract This invention refers to a medium voltage electric cable (up to about 45 kV) comprising one or more cores, each of said cores being constituted by a conductor covered with an inner semiconductive screen, an insulation layer of extruded polymeric material (preferably, cross-linked polyethylene or ethylenepropylene rubber) and an outer semiconductive screen. The outer semiconductive screen, which is extruded on the insulation and vulcanized at the same time as the insulation in a continuous vulcanizing line, is constituted by a mixture based on a blend of nitrile rubber and ethylene-propylene rubber and containing carbon black, cross-linking agents and various additives. The blend of nitrile rubber and ethylene-propylene rubber comprises 50-70 parts by weight of nitrile rubber and 50-30 parts by weight of ethylene-propylene rubber. The so constituted outer semiconductive screen has good adhesion to the insulation and can be easily removed from said insulation.

Inventors

  • 👤 Mario Castelli
  • 👤 Bruno Martini

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 20:34
CPC Classifications
H; H01; H01B; H01B13/00; H01B13/06; H01B13/14; H01B13/148; H01B13/22; H01B13/24; H01B9/00; H01B9/02; H01B9/027

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 98 words
A medium voltage electric cable having at least one conductor, each conductor being covered by an inner semiconductive screen in contact therewith, a layer of extruded, cross-linked polymeric insulation around said inner screen, and a readily peelable outer semiconductive screen around said layer of insulation and adhering thereto, said outer semiconductive screen being a chemically cross-linked rubber comprising a cross-linked blend of 50-70 parts by weight of nitrile rubber and 50-30 parts by weight of ethylene-propylene rubber, carbon black and cross-linking agents, said blend constituting at least about one-half by weight of the material of said outer screen.
Claim 2
Independent Claim 98 words
A medium voltage electric cable having at least one conductor, each conductor being covered by an inner semiconductive screen in contact therewith, a layer of extruded, cross-linked polymeric insulation around said inner screen, and a readily peelable outer semiconductive screen around said layer of insulation and adhering thereto, said outer semiconductive screen being a chemically cross-linked rubber comprising a cross-linked blend of 50-70 parts by weight of nitrile rubber and 50-30 parts by weight of ethylene-propylene rubber, carbon black and cross-linking agents, said blend constituting at least about one-half by weight of the material of said outer screen.
Claim 3
Dependent Claim 27 words
A cable as set forth in claim 1 wherein said blend contains 65 parts by weight of nitrile rubber and 35 parts by weight of ethylene-propylene rubber.
Claim 4
Dependent Claim 27 words
A cable as set forth in claim 1 or 2 wherein said nitrile rubber is a butadiene-acrylonitrile copolymer comprising at least 35 parts by weight of acrylonitrile.
Claim 5
Dependent Claim 18 words
A cable as set forth in claim 3 wherein the material of said outer screen comprises chlorinated polyethylene.
Claim 6
Dependent Claim 36 words
A cable as set forth in claim 4 wherein the material of said outer screen comprises no greater than 10 parts by weight of chlorinated polyethylene per 100 parts by weight of the outer screen material.
Claim 7
Dependent Claim 20 words
A cable as set forth on claim 1 or 2 wherein the material of said outer screen comprises chlorinated polyethylene.
Claim 8
Dependent Claim 36 words
A cable as set forth in claim 6 wherein the material of said outer screen comprises no greater than 10 parts by weight of chlorinated polyethylene per 100 parts by weight of the outer screen material.

References Cited (Backward Citations)

US2446387A Cited
US2471752A Cited
US3862056A Cited
US3645958A Cited
US4132698A Cited
US3885085A Cited
US4226823A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1985-08-02 1986-02-01 1986-08-03 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1989-08-02 1990-02-01 1990-08-03 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1993-08-02 1994-02-01 1994-08-03 $7700.00 Window Closed / Lapsed

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