US1921606A

US1921606A - Multicore high tension cable

Info

Publication number: US1921606A
Application number: US466655A
Authority: US
Inventors: Cremer Carl
Original assignee: Individual
Current assignee: Individual
Priority date: 1928-11-01
Filing date: 1930-07-09
Publication date: 1933-08-08
Anticipated expiration: 1950-08-08

Description

Aug. 8, 1933. c. CREMER 15 2 5 MULTIUORE HIGH TENSION CABLE Filed July 9. 1930 2 Sheets-Sheet 1 awe, 5W

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MULTICORE HIGH TENSION CABLE Filed July 9, 1930 2 Sheets-Sheet 2 Patented Aug. 8 1933 UNITED STATES MULTICORE HIGH TENSION CABLE- Carl Cremer, Copenick-Wendenschloss, near Berlin, Germany Application July 9, 1930, Serial No. 466,655, and

5 Claims.

When twisting together single-core cables 'so as to form multi-core cables, of which the individual conductors are of round cross sectional area, it is a known fact, that between the individual conductors triangular gusset spaces are formed which, in order to ensure a round total crors section of the cable, are filled up with packing material consisting of jute, paper or the like. In cables with a common lead sheath this packing is not subjected to the influences of the moisture of the ground or, in other words, it is protected. In cables, however, formed by twisting together a plurality of single-core cables, of which each one is encased in a lead sheath, 9. common lead sheath is, as a rule, dispensed with. In view of the fact, that the'ordinary armouring and jute covering will not be capable of preventing with absolute certainty the penetration of moisture, the packing in this case is ex-' posed to the risk of gradual perishing, if the cable is embedded in moist ground.

In accordance with the present invention, this drawback will be obviated, by filling up the gusset spaces formed when twisting the separate lead covered cables together, with lead tubes lying closely against the circumference of the separate cables and of the armouring. In connection herewith it will be possible to fill up the interior of these lead tubes with a filling material such as jute, paper or the like.

The cable in accordance with the present invention is suitably made in such a manner, that the lead tubes used for filling up the gusset spaces, possess a circular cross sectional area.

prior to the twisting operation and are pressed into segmental shape only during the twisting operation by the nipple finally ensuring a circular total cross sectional area of the cable...

In conjunction with girdle insulation and common lead covering it has been suggested to enclose the filling up packing in metallic layers for the purpose of rendering harmless the tangential tensions met with in such cables upon the surface of the individual conductors. A protection of the packing against the penetration of moisture is not intended in this case, in view of the fact, that the common lead covering renders the whole of the interior of the cable moisture-proof.

Apart from the protection of the packing against moisture, the construction of the cable according to the present invention, embodies 'still further advantages. In consideration of the fact, that the packing tubes are lying snugly against the lead covering of the separate twisted Germany November 1, 1928 "cable conductors, they assist the carrying oil of heat of the latter, especiallyalso in a radial direction, as the segment-like surfaces of, the packing tubes directly adjacent the cable circumference conduct the heat in an outward direction to a considerable degree. These surfaces further offer a convenient rest for the armouring surrounding the cable- It is known that, as a rule, a layer of jute is placed between the iron armouring and the cable, in order to prevent the armouring being pressed into the lead covering of the conductors. It now the lead. tubes used as. packing for the gusset spaces are made to be of such dimensions, that after the twisting the external segments of these tubes are projecting a short distance above the circle described by the three conductors, every possibility of pressure of the iron armouring upon the cable conductors will be obviated with absolute certainty, since the radial pressures caused by the armouring are taken up by the segments of the packing tubes and are distributed over the whole of the cable. The layer of jute below the armouring may, for this reason, be extremely thin, for instance, it will' be possible to make use of one jute tape only for holding together the conductors, thus considerably improving the heat conducting properties of the loadedcables, thereby attaining at an equal admissible temperature in the interior of the cable a higher load capacity.

Fig. 1 illustrates in a three-core cable the position of the three cable conductors and the packing strands, prior to their introduction into the twisting nipple; 1 represents the three conductors. 2 the insulating layers and 3 the lead covering of the individual cables. These lead coverings may, in order to increase. the margin of safety in regard to absolute tightness and protection against the consequences of porous places accidentally present in the lead coverings, each consist of two or more coverings pressed upon each other, each covering being 5 coated with a packing layer consisting of compound mass or the like prior to pressing one covering upon the previous one. .The round packing strands 5 are surrounded by thin lead coverings .4. a

Fig. 2 represents the cross sectional area of the finished cable. The packing strands 5 together with their lead coverings 4 have been pressed into the triangular gusset spaces, yielding a circular total cross sectional area of the cable. v

-Qwing to the fact, that the lead coverings they may easily be made to assume the triangularshape of the gusset without collapsing, the filling 5 may be omitted. In this case the gusset spaces represent hollow channels adapted for the passage of a cooling medium.

-7 is the external iron armouring and 6 the thin intermediate'layer of jute or the like. 8 is the usual layer of jute placed over the armouring 7.

Fig. 3 shows a modification of the" cable according to the invention, in which the hollow spaces are used for accommodating testing and signalling wires or the like 9.

Instead of so choosing the cross sectional area of the packing tubes that their contours are formed of three circular segments, the cross sectional area may be such, as shown in Fig. 4, where only the two surfaces 11, lying closely against the conductors, have the shape of a cylinder segment, whilst a straight surface 12 is formed in the outward direction against the armouring. The cross section of the whole of the cable will then have the shape of atriangle with rounded off corners 13.

Having now particularly described and ascertained the nature of my said invention, I declare that what I claim is:--

1. A multi-core high tension cable comprising a combination 01' a plurality of single core cables twisted together and surrounded by an amouring permeable for liquids, each individual single core cable consisting of a conductor, an insulation surrounding said conductor and a lead sheath surrounding said insulation, and lead tubes with walls impermeable for liquids, lying with walls impermeable tor liquids lying in and filling up the-valleys between the single core cables and the armouring and resting closely against the circumference of the individual cables and the armouring and a filling material filling up the interior of the said lead tubes. I

3. A multi-core high tension cable comprising a combination of a plurality of" 'single core cables twisted together and surrounded by an armouring permeable for liquids, each individcables and the armouring, said lead tubes having arched triangular shape and projecting in the cross-sectional area radially beyond the circle circumscribing the single core cables.

- 4. A multi-core high tension cable-comprising a combination of a plurality of single corecables twisted together and surrounded by an armouringpermeable for liquids, each individual single core cable consisting of a conductor, an insula' tion surrounding said conductor and a lead sheath surrounding said insulation, lead tubes with walls impermeable .for liquids lying in and filling up the valleys between the single core cables and the armouring and resting closely against the circumference of the individual cables and the armouring, a filling material filling up the interior of said lead tubes and testing and signalling wires embedded in the said filling material.

5, In manufacturing a moisture-proof multicore cable the method of twisting together a plurality of single core lead covered cables andan equal number of round tubes of soft lead in a twisting-machine, each of said round tubes in passing through the twisting-machine being deformed to a substantially triangular cross-sec-' tion equal in size and shape to the space between any two of the single core cables and the circle circumscribing the single core cables.

CARL CREMER.