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Publication numberUS3180926 A
Publication typeGrant
Publication dateApr 27, 1965
Filing dateDec 28, 1961
Priority dateDec 28, 1961
Publication numberUS 3180926 A, US 3180926A, US-A-3180926, US3180926 A, US3180926A
InventorsTrill Sidney W
Original AssigneePhelps Dodge Copper Prod
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Water-proof coaxial cable with readily separable layer
US 3180926 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

April 27, 1965 s. w. TRILL 3,180,926


SIDNEY W. TRILL United dtates Patent 3,180,926 WATER-PRUQF C(UAXIAL CABLE 'l JilTll READZLY SEPARAELE LAYER Sidney W. Trill, carsdale, NEL, assigncr to Phelps Hodge Copper Products (Importation, New Yorlr, FLY a corporation of Delaware Filed Dec. 28, 1961, Ser. No. 162,773 Claims. (6!. l74=ld7) The present invention relates to electrical cable and more particularly to an improved coaxial cable.

it is desirable that coaxial cable laid under water or under wet ground resist longitudinal movement of water through the cable. It is also desirable that layers of a coaxial cable be readily separable to connect their conductors to other cables, to junction boxes, or for testing of the cable. At the present time coaxial cables are'not particularly well adapted to withstand longitudinal water pressure, norare they particularly well adapted to have their layers readily separable for splicing.

It is an objective of the present invention to provide a coaxial cable in which the insulation around the outer conductor is easily extrudable and, after extrusion, readily separable from the remainder of the cable. it is a further objective that the insulation adjacent the outer conductor provide protection against longitudinal passage of In accordance with the present invention, a coaxial cable is provided in which a filled compound of a mixture of polyethylene, polyisobutylene and a mineral filler, preferably powdered acid magnesium metasilicate, is extruded over or under or within the spaces of the braided outer conductor of the coaxial cable. The filler renders the dielectrical material about the braid less cohesive and enables the outer conductor to be readily separated from the other portions of the cable. The filler selected for this purpose should be non-hygroscopic and unsusceptible to fungus and should not increase the electrical attenuation or otherwise alter the electrical characteristics of the cable.

Other features of the present invention will be apparent from the below detailed description of a preferred embodiment, taken in conjunction with the accompanying drawing in which the single figure is a side elevational view showing a coaxial cable embodying the present invention.

In the drawing, the coaxial cable comprises an inner electrical conductor 1, generally of copper wire. The inner conductor 1 is surrounded by a layer 2 of electrically insulative material, preferably polyethylene which is extruded over conductor 1. An outer conductor 3, preferably of braided copper wire, surrounds the insulative layer 2. A covering layer 4 of a mixture of mineral filler, polyisobutylene and polyethylene surrounds the outer Patented Apr. 27, 1965 conductor 3 and is preferably extruded onto conductor 3. Talc (powdered acid magnesium metasilicate) is the preferred mineral filler although diatomaceous earth, whiting (calcium carbonate), silica (silica dioxide), or hard or soft clays (mixtures containing hydrous aluminous minerals) may be used. A preferred mixture for layer 4 is polyethylene, polyisobutylene and tale, in equal proportions by weight.

A weather protective layer 5, preferably of extruded polyethylene containing carbon black and an antioxidant, covers layer 4.

Although the above description and the drawing relate to the use of the filled polyethylene-polyisobutylene material on the outside of the outer conductor, it is often desirable that the filled polyethylene-polyisobutylene material be applied underneath, over, and Within the interstices of the braided outer conductor 3.

Modifications may be made in the present invention within the scope of the subjoined claims.

I claim:

1. In a coaxial cable, the combination of an inner conductor, an insulative layer around the inner conductor, an outer conductor of braided wire around the insulative layer, and about the outer conductor, an extruded layer consisting essentially of a mixture of polyethylene, polyisobutylene and suflicient mineral filler to render the extruded layer relatively non-cohesive with the outer conductor so that the outer conductor and the extruded layer are readily separable.

2. The combination defined in claim 1, in which the mixture is composed of substantially equal proportions by volume of polyethylene, polyisobutylene and the mineral filler.

3. The combination defined in claim 1, in which said extruded layer substantially fills the interstices of the braid.

4. The combination defined in claim 1, in which the mineral filler is powdered acid magnesium rnetasilicatc.

5. The combination defined in claim 1, in which the mineral filler is whiting.



Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2387498 *Dec 6, 1941Oct 23, 1945Western Electric CoCoated article
US2622152 *Sep 21, 1946Dec 16, 1952Anaconda Wire & Cable CoHigh attenuation coaxial cable
CA508338A *Dec 21, 1954L. Hewitt NormanInsulated electrical conductors
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3351706 *Mar 18, 1965Nov 7, 1967Simplex Wire & Cable CoSpaced helically wound cable
US3355544 *Feb 24, 1965Nov 28, 1967Costley Vivian GSmall diameter high tensile strength coaxial electrical cable
US3943271 *May 6, 1974Mar 9, 1976General Cable CorporationExtruded solid dielectric high voltage cable resistant to electro-chemical trees
US4701575 *May 27, 1986Oct 20, 1987Comm/Scope CompanyJacketed cable with powder layer for enhanced corrosion and environmental protection
US5876528 *Feb 17, 1995Mar 2, 1999Bently Nevada CorporationApparatus and method for precluding fluid wicking
US6291773Feb 26, 1999Sep 18, 2001Bently Nevada CorporationApparatus and method for precluding fluid wicking
US6293005Mar 1, 1999Sep 25, 2001Bently Nevada CorporationCable and method for precluding fluid wicking
US6610932Aug 10, 2001Aug 26, 2003Bently Neveda, LlcCable and method for precluding fluid wicking
US6943319Nov 12, 2003Sep 13, 2005Msx, IncTriaxial heating cable system
US20050109753 *Nov 12, 2003May 26, 2005Jones Thaddeus M.Triaxial heating cable system
WO1996025782A1 *Feb 16, 1996Aug 22, 1996Bently Nevada CorporationApparatus and method for precluding fluid wicking
U.S. Classification174/107, 174/120.00R
International ClassificationH01B7/17, H01B11/18, H01B7/285
Cooperative ClassificationH01B7/285, H01B11/1869
European ClassificationH01B7/285, H01B11/18E