US1904887A

US1904887A - Electric cable

Info

Publication number: US1904887A
Application number: US353960A
Authority: US
Inventors: Shee Parke Lawton
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1929-04-10
Filing date: 1929-04-10
Publication date: 1933-04-18
Anticipated expiration: 1950-04-18

Description

P. L. sHEE ELECTRIC CABLE Aprilia, 1933.

Filed April l0, 1929 f the cable may be taken up and repaired be- Patented Apr. 18, 1933 UNITED.- STATES PATENT OFFICE PARKE LAWTON SEEE, 0F BE'RW'YN, ILLDTOIS, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW 'YORK ELECTRIC CABLE Application led April 10,

`and land cables having paper or similafii-,g brous insulation is to provide a relatively large amount 4of insulation which is compressed as much as is mechanically possible without injuring the insulation during the stranding process. This compact form is usedin order-that as much resistance as possible may be offered to the iiow of water in the event of a break in the sheathing and that fore a substantial length thereof is impaired p by the'water.

It has been suggested that by inserting plugs at intervals in under-water and land cables, the same effect can be obtained. The value of a plug lies chiefly in the fact that with its use a much more eiicient cablefmay be designed and constructed for, except at the actual plugging point, the cable 'may be made much less compact and therefore more eiii- 1 cient 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.

The primary object of this invention is to iprovide an electric cable having an` improved plug or seal which may be produced economically in a facile manner and is eiiicicnt in service.

In accorda-nce with the general features of this invention as applied,.for example, to submarine cables, the conductors along a comparatively short portion of the stranded cable core length are separated from each other to provide open convolutions. `This portion of the core is then treated with a waterproofing compound of a consistency which will thoroughly impregnato and waterproof the paper .insulating material. Thereafter the portion of the core having the treated and separated conductors is placed in a suitable cavity of a molding press and a composition, preferably containing an artificial resin such as a phenolic condensation product, is inserted in the mold cavity and around the con- -du ctors to fill all the spaces between the indi- 1929. Serial N0. 353,960.

vidual separated conductors. The press is then closed and simultaneously therewith the conductors are stretched taut by pulling upon the' core -at each side of the mold cavity and heat is applied to cure completely the phenolic plastic composition and to provide a moisture resistant wall or plug across the diameter of the core, which is of a width sufficiently narrow -to permit the cable to be coiled in the usual manner without deleterious effect on the plug or the cable core. During the application of heat and pressure to form the plug the core for a comparatively short distance at each side of the plug is also subjected to pressure to compact the core, but to a less degree than that applied to form the plug. Upon removal of the core from the mold cavity of the press the cable core as a whole is inserted in a suitably heated baking oven for asuitable period to remove any moisture which may be contained in the insulation of the core. The portion of the lcore containing the plug is wrapped for a few inches at each side of the plug with a rubber compound adhesive tape, v' i ust previous to the core being inserted in an extrusion press forv the application to the core of a lead sheath, for the purpose of providing a bond between the cured phenolic composition plug formed in the cable core and the lead sheath, the tape completely sealing and iilling all spaces between the outside of the plug and the adjacent compressed portions of the core and the inside of the lead sheath.

Other` objects and advantages of this invention will more fully appear from the following detailed description taken in connection with the accompanying drawing, wherein Fig. 1 illustrates a length of submarine cable shown partly in section with a plug embodying the features of this invention formed therein, and

Fig. 2 is an enlarged fragmentary section taken on the line 2--2 of Fig. 1.

Referring now to the drawin wherein like reference numera s indicate in detail' loo similar parts throughout the severalviews,

cable core lengthv previous to the sheathing thereof, which is to be provided with a plug of the type hereinbefore referred to, is hunched or worked for a distance of approximately two feet to separate the insulated conductors 10 from each other to provide open convolutions. lThis section of the cable core having the open convolutions is then subjected in any suitable manner topa "relatively thin waterproofing material which will completely impregnate the paper insulation of the individual conductors constituting the core. The waterproofing material may be of any suitable type, preferably such as that fully described in Patent 1,654,546, dated January 3, 1928, to F. S. Malin.

After impregnating the section of the core having the open conductor convolutions and in which the plug is to be formed with the waterproofing material previously referred to, this section of the core is placed in a suitable cavity of a molding press. Such a press may be of the usual hydraulic type provided with suitably shaped upper and lower mold or die sections. The spaces between the individually separatd conductors 10 after being positioned in the mold or die cavity of the press are completely packed or filled with a' molding composition, preferably containing an artificial resin such as a phenolic condensation product. The total amount of the product within the mold cavity isonly sufficient to insure after the subsequent curing of the product, to be presently described, that a unitary comparatively narrow mass of completely cured phenolic condensation product will extend across the diameter of the core with the insulated conductors extending therethrough. Any excess of the product inserted between the conductors will be forced along the conductors at each side of the point where the maximum pressure and heat is applied, thus providing sufiicient resistance and friction, as the press closes, lto maintain the central portion of the product in lposition and thus cause a perfect cure` thereof. The excess product movin 't0 each side of the central portion thereo willbe more or less uncured and consequently will not be as rigid as the cured central portion. The press is then closed, and slowly and simultaneouslyl therewith the conductors within the mold and Y cavity are stretched taut vby suitable pulling means ap lied to the core at each side of the mold cavity and heat is applied to cure completely the phenolic plastic composition and toprovide a moisture resistant wall or plug 12 across the diameter of the Score. The width of the wall 12 should preferably be one-half inch so as to permit the cable to be coiled in the usual manner without deleterious effect on the plug or the cable core. In Fig. 1 of the drawing the width of the cured wall 12 is indicated by the broken lines extending across the diameter of the Core.

Although it is likely that the wall 12 will not be of a uniform width throughout its extent, but will be irregularly formed, there will be formed a `wall or plug of 'an infusible and in soluble character with the conductors 10 substantiallyuniformly spaced extending therethrough, as clearly shown in Fig. 2.

The upper and lower mold sections of the press are designed in such a manner that during the application of heat and pressure the core for a comparatively short distance at each side of the wall is also subjected to pressure to compact the core therealong, but to a less degree than that applied to form the plug 12. Upon removal of the core from the mold cavity of the press, after the presos 1s opened, any fins formed around the perlphery of the core because of an excess phenolic condensation product extruded from between the mold sections are removed byv filling or otherwise. This operation will not be neces' sary in all instances, but will depend on the design of the mold or die sections. Thereafter the core, as a Whole, is inserted 1n a suitably heated baking oven for a suitable period to remove any moisture which may be contained in the insulation of the cable core.

Just previous to thev cable core being inserted in an extrusion press of a usual type for the application to the core of a lead sheath 13, an adhesive filling material, (preferably a wrapping of rubber compoun tape 14, is applied to the core for a few inches at each side of the wall or plug 12 for the purpose of providing a bond between the cured phenolic composition plug formed' in the cable core and the lead sheath and increase the diameter of the slightly compressed portions of the-core at each side of the plug to the size of the uncompressed portion o the core. The rubber compound tape 14 ma be of anysuitable type which will be of a c aracter to fill and seal the ace between the outsideof the plug 12 arid the adjacent compressed portions of the core and the inside of the lead sheath 13 when the sheath is applied thereto. Preferably, for this purpose there is employed a tape formed from materialof the type fully described in Patent 1,654,297, dated December 27, 1927, 'to F. S. Malm. A ta made u from the material described in t e refe to patent is of such a character that the heat of the lead sheath 13 when applied is suicient to cause the adhesive tape to fill completely all the spaces between the core pl v 12 and the sheath 13 and to adhere to the a jacent surfaces thereof. When the sheath 13 is in place the usual hemp covering 15, the steel armour 16, and the outer jute covering 17 are applied in the usual manner. In the case of land or aerial cables the last .mentioned coverings of hemp, steel varmour and jute are omitted.

It will be apparent that a submarine lcable plug embodying the features of this invention adhesive *4.5 ductors with a charge of phenolic condensaoffers a maximum resistance to the flow of water in the event of a break in the sheathing of the cable andv that upon a leak developing,

the portion of the cable affected will be con-` and electrical insulating bafile'in an electric.

cable, which comprises separating the individual insulated conductors forming the cable along a portion of the core length, positioning around the separated condutors a charge cfa moisture resistant and electrical insullating/molding material capable of solidifying when subjected to heat and pressure, maintaining the separated portion of the conductors taut and simultaneously therewith subjecting the charge to heat and pressure.

2. The method of making an electric'cable, which consists in assembling to form a cable core a plurality of insulated conductors, sepa'- rating the individual conductors along a portion of the core length, positioning around the separated conductors a charge of phenolic condensation product, maintaining the separate-d conductors taut, and contemporaneously therewith subjecting the charge to heat and pressure to produce a unitary completely cured mass forming a plug in the core.

3. The method of making an electric cable, which/consists in assembling to form a cable core a plurality of insulated conductors, separating the individual conductors along a portion of the core length, filling substantially all of the spaces between the separated contion product, and subjecting the charge to heat and pressure to produce a unitary completely cured mass forming a plug in the core.

4. The method of making an electric cable,

which includes the steps of assembling to form a cable core a plurality of insulated conductors, spreading the conductors along a portion of the core length, positioning the spread subjecting itto heat and pressure to produce a\unitary completely cured mass forming a plug in the core.

The method of making an electric cab`e, which consists in assembling to form a cable core a plurality of insulated conductors, sep-- arating the individual conductors along a portion of the corelength, positioning around the separated conductors a chargeof henolic condensation product, maintaining t e separated conductors taut and contemporaneously therewith subjecting the charge to heat and pressure and the core for a predetermined distance at each side thereof `to pressure to roduce a unitary completely cured mass orming a plug in the core, and building up the plug and the compressed portions of the core to the size of the uncompressed portion thereof.

6. The method of making a submarine cable, which consists in assembling to form a cab-e core aplurality of conductors having a fibrous insulation, separatin the individual conductors along a portion o the core length, impregnating the separated conductors, positioning around the separated individual conductors a charge of phenolic condensation product, subjecting the charge to heat and pressure and theV core for a predetermined distance at each side thereof to pressure to produce a unitary completely cured mass forming a plug in the core, subjecting the core thereafter to a dryingmedium to remove any g vmoisture. contained therein, building up the plug and the compressed portions of the core to the size of the uncompressed portion thereof, and applying a sheath to the core.

7. In an electric cable, a core comprising a plurality of insulated conductors, and a comparatively narrow rigid wall of moisture resistant material surrounding the individual conductorsalong a portion of the core length.

8. In an electric cable, a core comprising a plurality of insulated conductors, and a molded mass of artificial resin composition around the individual conductors along a portion of the core length providing a solid insulating impermeable plug in the core.

9. In an electric cable, a core comprlsmg a plurality of insulated conductors, and a unitary molded mass of artificial resln composition filling substantially all of the spaces between the individualv conductors along a comparatively short portiorrof the core length providing a solid Yinsulatlng impermeable plug in the core.`

10. In anelectric cable, a core comprising a plurality of insulated conductors, and a cured mass of phenolic condensation product posltioned around the individual conductors along a portion of the core length provldlng a solld insulating impermeable plug 1n the core substantially the diameter thereof.

11. In an electric cable, a core comprlsmg a plurality of conductors covered indlvidually with a fibrous insulating material, the 1nsulating material along a portlon of the core length being impregnated wlth a waterproofing material, and a unitary molded mass of artificial resin composition filling substantially all of the VKspaces .between the in dlf vidual conductors along a portion of the 1mpregnated core length. providing a solid inl sulatingimpermeable plug in the core. Y 12; In an electric cable, a core comprising a plurality of conductors, each covered individually, with a fibrous insulating material,

the insulating material along a portion of the core length being impregnated with a Waterproofing material, and a cured unitary mass of phenolic condensation product filling substantially all the spaces between the individual conductors along a comparatively short portion of the impregnated core length providing a solid insulating moisture resistant narrow wall across the diameter of the core. I

13. In a submarine cable, astranded core comprising a plurality of insulated conductors, each covered individually with a fibrous insulating material, the insulating material along a portion of the core length being impregnated with a waterproofing material, a cured unitary mass of phenolic condensation product illing substantially all the spaces between the individual conductors along a comparatively short portion of the impregnated core length providing a solid insulating moisture resistant narrow wall across the diameter of thecore and a reduced diameter lto the core for a `predetermined distance at and at each side of the Wall,-a metallic sheathsurroundin the core, and a. bonding material filling t e spaces between the reduced diameter portion of the Vcore and the sheath.

14. The method of making an electric cable which consists in assembling to form a cable core a pluralityof conductors, separating the individual conductors along a portion of the core length, positioning around the separated conductors a plastic moisture resistant material, and rendering the conductors taut to embed them entirely in the material.

15. 'Ihe method of making an electric cable which consists in assembling to form a cable core a plurality of conductors, separating the individual conductors along a portion ofthe core length, positioning around the separated conductors a plastic moisture resistant material, rendering the conductors taut 'to embed them the more .rmly in the material, and

curing the material to produce a narrow rigid wall between the individual conductors. p

1 6. The method of making an electric cable whlch includes the steps of assembling a plurality of insulated conductors toorm a cable i core, separating the conductors for a short distance, disposing a uantity of material containing uncured arti cial resin among and around the separated conductors, compressing the separated conductors together with the material, and heating the material to cure the artificial resin.

In witness whereof, I hereunto subscribe my name this 30th.day of March, A. D. 1929.

PARKE LAw'roN SHEE.