US1654546A - Electric cable - Google Patents

Description

Patentcd Jan. 3, 1928,

UNITED STATES 1,654,546 PATENT OFFICE.

rRANKsrernID' ALM, on CHICAGO, ILLINOIS, ASSIGNOR ro WESTERN ELECTRIC COMPANY, ncozromrn, on NEW YORK, N. Y., A CORPORATION or NEW YORK.

ELECTRIC CABLE.

Application filed April 6, 1823; Serial No. 630,201.

This invention rclates in general to electric cables, and more particularly to improvements in submarine cables.

The usual customin submarine 'cables having paper or similarlibrous insulaton is to provide a relatively large amount of insulation which is compressed as much as is mechanically possible without injuring the insulation during the stranding process.

This compact form is used in order that as much resistance as possible may be offered to the flow of water in the event of a break in the sheathing and that the cable may be taken up and repared before a substantial length thereof is ruined.

It has been suggested that by nserting plugs at intervals in under-water cables, the same etfect can be effected. The value of a plug lies chiefly in the fact that 'with its use a much more eflicient cable may be desgned and constructed, for except at the actual plugging point, the cable may be made much less compact and therefore more efiicient from a transmission standpoint than the type above mentioned. The cable can also be made with less insulating paper and of smaller diameter than is ordinarily possible.

It is the Object of the invention to provide a cable plug of this type which is inexpensive, easy to produce, and efficient in service.

In accordance with this Object the present invention contemplates administering two treatments to that portion of the'cable core where' the plug is to be made. The first treatment consists in subjecting this portion of the cable core to a relatively thin waterproofingcompound which will thoroughly impregnate and w-aterproof the paper or other fibrous insulating material; The second treatment consists in subjecting this portion of the core to a relatively heavy waterproofing compound which will fill all of the intersti'ces between the' individual strands constitutingthe core.

Plugs made in accorda'nce with this in`-- vention will also be of considerable value in land cables as well as in submarine cables when the plugs are placed in the ends of 5 the cables out of which wres are extended to terminals or for connection with other wires.

Theplugs in such cases will seal the ends of-the cables so as to exclude air and moisture, which is present in air, from entering 5 the cores of the cables and thus impairing the insulation of the wires within the cables.

The invention will be more clearly understood from a consideration of the following description taken in connection with the accompanying-drawings, in which conductors 1 are eovered in the usual manner with paper insulating material. A section 2 of v 'A material which has'been found to produce good results comprises rosin oil and rosin in approximately the proportions of 25 per cent of the -former to 7 5 per cent of'the latter, the compound being prepared by heating and stirring until a uniform mixture is produced.

After the section of the cable core has been treated with the impregnating compound above described, the surplus of the compound is permitted to drain ofl. This section of the core is then subjected to a relatively heavy -waterproofing material which is much more. Viscous than the material used in the first treatment. This heavy material will fill all of the interstices between the various conductors forming the stranded core. The compound used for this purpose should be of such acharacter as to flow comparatively freely at` a temperature of 230 F. in order ;to fill the interstiees of the' cable and should -not become hard and brittle at temperatures as low as approximately 32 F. Very good success has been had using a compound for this purpose comprising the following ingredients in approxi- 'mately the proportions stated:

Per cent.

Rosin oil 25 Rosin 5 Asphaltum 70 After impregnating the section of the core which is to form the plug with the waterproofing compound above described, this 'section of the core is wrapped one or more times with elastic rubber tape 3 with sufiicient tension accumulatively applied to the tape to bind the cahle core into a very compact mass. After the core has been closely confined at this point by means of the rubber tape 3 it is further wrappedwith an adhesive imm'egnated fahric tape 4: of any suitahle character. A filling material lS then used to build up the dianeter of the core io approxi'ately that desired. The tilling material may he of any suitable type which will be of a character to seal the space between the outside oi" the tahric tape 4 and the inside of the lead sheath when tle said sheath is applied thereto. Preterahly l employ for this purpose material of the type described and *l'ully disclosed in my co-pending application, Serial No. 631,360, filed April 11, 1923.

According to the disclosure of the atorementioned copending application, a satis- 'actory adhesive conpound of this type may comprise a plastic gum, an adhesive material which also has a softening action uponthe plastic gum, anda fibrous illing` material to give the compound a relatively high viscosity. .The fibers intermingle and accumulate in any small -passages through which the compound may have a tendency to 'flow and thus obst-ruct the free flow thereot.

The plastic gum may be crude or plantation rubber, gutta percha, balata, pontianac, or the like. Preferably 1 employ washed and dried crude or plantation rubber sottened with rosin and rosin oil which are also adhesive materials, the mixture being lilled with asbestos fibers. Ashestos fibers are prezterably employed since the compound may be suhjected to temperaturcs as high as 250 F., especially where the compound 'is `used as an adhesive and sealing; material in the mannfacture of cable plugs.

l find that a satstactory compound may be made using the :tollowngmaterials in the proportions stated:

l'er cent. `Washed and dred crude rubber or plantation rubher 59 Rosin oil 6 Rosin w 23 Asbestos fibers 12 A compound cmbodying these ingredients in the proportions shown will remain tacl y and adhesive *from temperatures ranging between about 32 F. and 250 F. or at anv temperature to which it is suhjected during its use in cahle plugs. Its consisteney is such that it will adhere to metallic surfaces even where Such surtaces have a comparatively high polish.

The 'toregoing described adhesive compound is of such character that the heat ot the lead covering 6 when applied is suiieient 'to cause the said material, indicated in the drawings by the reference numeral 5, to llow into a homogeneons mass to completely hll the spaces between the core and sheath and to adhere to the adjacent surfaces thereot. Wheu the lead sheath is in place, the usual hemp covering 7, the stecl armor 8, and the outer jute covering 9 are applied in the standard manner.

What is claimed is:

l. The method of making a plug in a cahle having a stranded core the individual strands of which are insulated with librous material, which consists in subjecting a section of the cable core to two waterprooling materials, one more viscous than the other, and subsequently compressing the treated section sufiticiently to cause one of the waterproofing materials to till the interstices of the insulating material and the core.

2. The method ot making a plug in a cable comprising a 'stranded core, the individual strands ol which are insulated with ibrous material, which consists in subjecting a section ot the cable core to a waterprooting; material which will. impregnate the fibrous insulating material subgecting the said section of the core to another waterprooiing material, and subsequently compressing the said section of the core sntliciently to cause the last mentioned waterproong material to till the spaces between theindividual conductors of the stranded core.

The method of making a plug in a cahle comprising a stranded core, the individual strands of which are insulated with tibrous material, which consists in subjectine` a see tion of the cable core to a relatively thin waterproofing material which will impre rnate the said tilorous insulation, then suhjecting the said section to a relatively heavy waterproofing material, and then compressing the core sulliciently to cause the last mentioned waterproofing material to lill the spaces between the individual strands of the stranded core.

4. :in an electric Cable, a plurality oil' conductors, librous insulatine"material covermg each of said conductors individually, said .tibrous material impregnated with a waterprooling material, a second \vaterprmting material being so disposed as to till suhstantially all of the spaces between the individual conductors constitution' the stranded core.

5. ln an electric cable, a plurality of conductors, librous insulating material covering each of said conductors individually,

, said fibrous material being impregnated with a waterproofing material, a waterproong material more viscons than the'first meritioned material being so disposed as to ll substantially all of the spaces between the individual conductors constitutinrg stranded core.

la an electric Cable, a plurality of con.-

`ductors, fibrous insulating material covering each of said ccnductors.individually, Said insulating material being- .impregnated witha waterproofing material, waterproofing material more viscous than the waterproofing material' first mentioned being disposed between the individual conductors constituting the stranded core, and said conductors being compressed so that said last mentioned waterproofing material fills substantially all of the interstices between the eonductors constituting the stranded core.

7. In an electric Cable, a core comprising.

a plurality of conductors, fibrous insulating material covering each of said conductors individually, a metallic sheath surrounding said-cere,--andan adhesive material filling the spaces between said core and said sheath and adhering to the surface of the said sheath.

8. In an electric cable, a core comprising a plurality of conductors, fibrous insulating material covering each of said conductors individually, a metallic sheath surrounding said core, and an adhesive material filling the spaces between said core and said sheath and adhering to the adjacent surfaces thereof.

9. In an electric Cable, a plug comprising a plurality of closely confined individually insulated conductors, the diameter of the core* of said plug being smaller than that of the adjacen-tportions of the cable core, a metallic sheath disposed about said plug, and an adhesive and homogeneous material disposed between said plug and said sheath to build up said plug to fitsaid sheath and fill all spaces therebetween, said material adhering to the adjacent surfaces of the plug and sh'eath.

10. In an electric Cable, a plnrality of conducto-rs, fibrous nsulatng material coverng* each of Said conductors individually, said fibrous material being impregnated with a waterproofing material, a waterproofing mav terial more viscous than the' first mentioned material being so disposed as to fill substan-,

tially all of the spaces between the individual conductors, a netallic sheath surrounding the' conductors, and an adhesive material filling the spaces' between said core and said sheath and adhering to the adj acent surfaces thereofj A 11. In an electric cable, a plurality of conductors, brons'insulating material c'overing each of said conductors indivi-dually, said insulating material being impregnated with. a'

wateijproofing material, waterproofing material more .viscous than the waterproofing material firstmentoned being disposed beproofing materials, one more viscous than the other, and subsequently wrappng the treated section of the cable in such manner as to compress the section suficiently to cause one of the waterproofing materials to fill' the i nterstices between the individual strands of the stranded core. V

r 13. In an electric cable, a plurality of conductors, fibrous insulating material covering each of said conduct'ors individually, said fibrous material being impregnated with a waterproofing material,--a waterproofing material more viscous tha-n the first mentoned material being so disposed as to fill substantially all of the spaces between the individual cc-n'ductors, and a compressing wrapper over the treated conductors' 14. ln an electric Cable, a plurality of conductors, fibrous insulating material covering each f said conductors individually, said fibrous material being impregnated with a waterproofing material, a waterproofin material more viscous than the first mentioned material being so disposed as to fill substan tially all of the spaces between the individual conductors, and an elastic compressing wrapper over the treated conductors.

15. In an electric cable, a plurality of conductors, fibrous insulating material covering each of said conductors individually, said fibrous material being'impregnated with a waterproofing material, a waterproofing' material more Viscousthan the first mentioned material being so disposed as a fill substantially all of the spaces between the individualconductors, a conpressing wrapping around the treated condnctors, a metallic sheath surrounding the wrapping, and an adhesive material -filling the space between the wrapping and the sheath and adhering to the adjacent surfaces thereof. i

In* witness whereof, I hereunto subscribe my name this 27 day of March A. D., 1923. FRANK SIGFRID MALM.

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