US1956723A - Joint for oil-filled cables - Google Patents

Description

y 93 1.. KUNST 1,956,723

JOINT FOR OIL FILLED CABLES Filed June 25, 1931 Patented May I, 1934 1,956,723 JOINT FOR OIL-FILLED CABLES Ludwig Kunst, Berlin-Charlottenburg,

Siemens-Schuckertwerke Aktienassignor to Germany,

gesellschaft, Berlin-Siemensstadt, Germany, a corporation of Germany Application June 25, 1931, Serial No. 546,745

In Germany July 4, 1930 2 Claims.

My invention relates to joints for oil-filled multi-conductor cables and has for its primary object to provide an improved protective seal for the oil-filled channels as well as an oil-conveying connection of improved construction between contiguous cable lengths.

It is old and well known in the art to provide individual insulated-conductors of an oil-filled multiple-conductor cable with a seamless metal sheath and to cover the stranded lead-sheathed insulated conductors with an additional seamless metal sheath, the interspaces between the common seamless metal sheath and the stranded metalsheathed, insulated conductors being filled with oil. With a cable of that kind, there is danger that the outer lead sheath may become damaged and thus permit the oil between this sheath and the stranded single-conductor cables to absorb moisture. In this event, should the adulterated 39 oil penetrate into the joint box and reach the point where the conductors are joined and particularly their insulation, the electric properties of the joint will be so impaired that a breakdown is liable to occur.

In order to overcome this drawback, my invention contemplates a socket connection of improved construction between the end of the common lead sheath and the individual insulated conductors at points where the cable enters and leaves the joint box. For the purpose of providing an oil-tight closure of the oil-filled spaces, the socket connection may be applied at one end to the common lead sheath which surrounds the insulated conductors and at its other end provided with tubular extensions attached to the leadsheathed insulated conductors of the cable, oiltight seals being formed between said socket connection and the common lead sheath and between said socket connection and the lead sheaths ofthe individual insulated conductors.

An illustrative embodiment of my invention is shown on the drawing in which Figure 1 is a longitudinal section of a joint connection for oil-filled multi-conductor cables constructed according to the present invention.

Figure 2 is a cross-section of Figure 1 on the line A-B.

Figure 3 is a longitudinal section of a cable joint connection similar to that shown in Figure 1 in which the oil-filled chambers of successive sections .of the multi-conductor cable are connected by a tubular connection arranged interiorly of the joint box or housing.

Figure 4 is a longitudinal section of a similar joint connection in which the oil-filled chambers of successive sections of the cable have a tubular oil connection arranged exteriorly of the joint box or housing.

In the drawing, the numerals 1 and 2 indicate two insulated conductors of a cable which ex- 80 tends into a joint box 3. Said insulated conductors are provided with metal sheaths 11 and 12, respectively, and surrounded by a common lead sheath 4. 5 and 6 are the insulation wrappings at the joints between contiguous lengths of the conductors 1 and 2. In order to provide an eifective oil seal for the spaces between the common lead sheath and the individual lead sheaths of the insulated conductors and between said individual lead sheaths, and thus preventing the oil from penetrating into the joint box 3 where it would reach the insulating wrappings 5 and 6, a socket connection 7 may be provided and attached with an oil-tight seal to the common lead sheath 4. Tubular extensions 13 may be similarly attached to the individual lead sheaths 11 and 12 for the insulated conductors. The oil-tight joints between the common lead sheath 4 and said socket connection and between said socket connection and the lead sheaths 11 and 12 of the 30 insulated conductors 7 may be made suitably by the application of thick layers of solder at the places indicated by the numeral 8. To maintain the flow of oil from one cable length to the next cable length contiguous thereto, the socket connection 7 may be provided with a tubular extension 9 to which a flexible tube or pipe 10 may be connected with an oil-tight seal for forming an oil-conveying connection with the corresponding socket connection on the cable length next contiguous thereto. By means of this device, it is possible to maintain a flow of oil past the joint box without it reaching the insulation of the cable. As shown in Figure 4, a substantially similar result may be obtained by providing a connection branch 14 leading from the oil spaces within the common lead sheath and extending on the outside of the joint box to the corresponding common lead sheath of the adjacent cable length. In the same manner, oil may be prevented from pene-'- trating into the potheads in which case the oil conveying tube leading from the socket connection or oil spaces-is placed in communication with an oil equalizing tank provided, it necessary, outside of the pothead.

I claim:-

1. The combination with joined sections of an oil-filled multi-conductor cable comprising insulated conductors respectively enclosed in indlvidual lead sheaths and having a lead sheath common to and surrounding all of said sheathed insulated conductors, the spaces between saidlead sheaths and a lead sheath common to and surrounding all of said insulated conductors, the spaces between said individual lead sheaths and the common surrounding lead sheath being filled with oil, a socket connection for hermetically sealing said oil-filled spaces around the end of said common surrounding lead sheath, said socketv connection forming a permanent oil-tight seal with said common lead sheath and having tubular extensions respectively forming oil-tight seals with the individual lead sheaths for said insulated conductors, and an oil-conveying tube for connecting the oil spaces of contiguous lengths of the multi-conductor cable. i

' LUDWIG KUNST.

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