US2516747A - Fluid impregnated electric cable - Google Patents

Description

July 25, 1950 c. E. BENNETT FLUID IMPREGNATED ELECTRIC CABLE Ftiled Aug. 29, 1945 Water a Moistureproof Sealing Agent Vornished Gloss Inventor CHARLES E.BENNETT DJ J. M

flltorney Patented July 25, 1950 25 16347 FLUID HHPREGNATED ELECTRIC CABLE Charles E. Bennett, Ridgewood, N. J., assignor-to' The konite-Callender Cable Company, Incorporated, Paterson, N

Jersey a. corporation of New Application August 29, 1945, Serial No. 613,257

line filled with insulating fluid maintained under superatmospheric pressure.

It is customary under present practice to insulate these conductors at the factory, impreg-- hate them with insulating fluid, and then to encase each conductor in a temporary lead sheath to retain the impregnant and to prevent the entry of moisture to the insulation in transit and while installing. This sheath adds materially to the cable cost to the customer, in time, labor and material; the sheath adds considerably to the weight of the cable thus increasing shipping costs; and finally the sheath has to be removed at the installation site involving more expense.

The present invention provides a construction wherein the temporary lead sheath is dispensed with entirely, and the expense incident to its use eliminated.

2 Claims. (Cl. 17425) In the accompanying drawings, I have illus- I trated two embodiments of my invention.

Fig. l is a cross section through a sealed cable system of the type wherein several individually insulated conductors are enclosed in a pipe line containing insulating fluid under superatmospheric pressure.

Fig. 2 is a fragmentary part sectional elevational view of one of the conductors of the cable system of Fig. 1; and

Fig. 3 is a view similar to Fig. 2 of another embodiment of my invention.

Referring to the drawings in detail, and first of all to Figs. 1 and 2:

2 designates the individually insulated conductors of a sealed cable system wherein these conductors are enclosed in a pipe line 4 filled with insulating fluid maintained under superatmospheric pressure or the order of two hundred pounds per square inch.

Each conductor 2 is insulated with paper tape 6 which in accordance with conventional practice is wound hellcally about the conductor, layer upon layer until the desired wall thickness has been built up.

About the paper insulation 6 I wrap a moistureand waterproof tape 8 of aluminum or other metal foil, or a tape of paper treated to render it moistureand waterproof. This tape is wound hellcall with a substantial overlap, and covered with a waterand moistureproof sealing agent such as polybutene sold commercially under the name of Vistas. The tape itself being moistureand waterproof and sealed with Vistag, it will be apparent that no moisture or water can pass through the sheath thus provided, and that the fluid insulation with which the conductor insulation is impregnated before leaving the factory cannot escape.

In installing this type of cable long lengths are drawn into the pipe line 4. It is necessary that the cable be protected against damage in this operation.

Accordingly I wrap heavy canvas tape it about the impervious sheath just described. The carevas tape ID is wrapped helically and is inter calated with metal shielding tape 12. The shielding tape is imperforate.

As a further protection against damage and to facilitate drawing in of the cable I wrap metal armor wire it about the cable exterior. This armor is D-shaped in cross section, with its fiat side in contact with the cable, and wound with a long pitch in the opposite hand to the wraps beneath it.

It will be apparent from the foregoing that my invention provides a cable construction wherein the cable conductor is finished at the factory, that is insulated and impregnated, and may be shipped and installed without danger of loss of the fluid insulation, without injury because of moisture or water, and without the necessity of removing the temporary lead sheath heretofore found necessary to protect the cable. Obviously this is a considerable advance over conventional practice.

In the construction illustrated in Fig. 3, I have provided a somewhat simpler construction than the one Just described but with all of the advantages thereof. J

In this embodiment of my invention I employ insulating paper tape 8 as before, and immediately about this insulation I wrap imperforate shielding metal tape l6, copper, for example, intercalated with varnished glass tape l8. A coating of a sealing agent such, for example, as the Vistag above referred to, is applied over these tapes so as thoroughly to seal the same against the entry of water or moisture.

As in the embodiment of my invention first described, D-armor I4 is applied to the cable exterior, being-wound in the opposite hand to the intercalated tapes l8 and I8.

It will be appreciated that in both embodiments of my invention the necessity for a temporary lead or other sheath, with the expense incident thereto, is eliminated, yet the cable is at all times fully protected against loss of the cable impregnant and .against the deleterious efiects of the elements.

It is to be understood that changes may be made in the details of construction and arrange ment of parts hereinabove described within the purview of my invention.

What-I claim is: 1

1. A high tension cable installation comprising in combination a conductor, a wall of porous insulation around the conductor, an imperforate fiexlblesheath of waterand moisture proof material wrapped helically about the said insulation, a permanent water and moisture-proof sealing coating for said sheath, intercalated tapes of metal and fabric wound helically over said coating, a solid metal strip wrapped in an open helix about the last mentioned tapes, a body of fluid insulating material filling the porous insulation and all spaces beneath the said sealing coating, 9. fluid-tight pipe enclosing the .cable, the internal diameter of the pipe being large enough relative to the overall dimensions of the cable to permit the cable to be drawn into the pipe, and a body of fluid ,under superatmospheric pressure filling the space between the sheathed cable and the wall of the pipe.

2. A high tension cable installation comprising in combination a conductor, a wallof porous insulation around the conductor, an imperforate' flexible sheath of water-and moisture-proof material wrapped helically about the said insulation,

a permanent water and moisture-proof sealing coating for said sheath, a metal shielding tape intercalated with a fabric tape. wound helically 'over said coating, 9. solid metal strip wrapped in an open helix about the last mentioned tapes, a body of fluid insulating material .filling the porous insulation and all spaces beneath the said sealing coating, a fluid-tight pipe enclosing the cable, theinternal diameter of. the pipe being large enough relative to the overall dimension of the cable to permit the cable to be drawn into .7 thepipe, and a body of fluid under superatmospheric pressure filling the space between the sheathed cable and the wall of the pipe.

CHARLES E. BENNETT.

' REFERENCES CITED The following references are of record in the file of this patent:

England Jan. 26, 1937

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