US1834864A

US1834864A - Joint for high tension electric cables

Info

Publication number: US1834864A
Application number: US497650A
Authority: US
Inventors: Lester L Phillips
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1930-11-24
Filing date: 1930-11-24
Publication date: 1931-12-01
Anticipated expiration: 1948-12-01

Description

Dec. 1, 193i. L. L.. PHBLMPS JOINT FOR HIGH TENSION ELECTRIC CABLES Filed Nov. 24, 1950 s, .WM MP7@ ML ,w ,mm m L H M Patented Der..` I, 1.931

LUNITED.STA'IYES. PATENT usi-,ann

rmnm, or rrr'rsrmnn, nss'ncnusnrrs, assIGNon' ro GENERAL ELEC- rnrc conm, a conroaarron or NEW Yonx JOINT FOB HIGH TENSION ELECTRIC CABLES Application nled November 24,11930.. Serial No. 497,650.

The present invention relates to` what are commonly known as stop-joints .for luld lilled electric cable. p-'Iheir purpose is to elecz trically connect corresponding ends of` cable A sections, prevent all migration of the insulatconductor ends, then a connector soldered or otherwise secured tosaid ends, after which a large amount of insulating tape is wound j over the connector andalso over the permanently 'woundvfactory insulation on the con-` f ductors themselves. Asthe operating volt-y age of the cable is increased, the amount of tape required is likewise increased but at a much greater ratio. The tape as supplied is in the form of rolls and experience has demonstrated that lar e diameter reinforce- ,ments cannot. be ma e sufficiently firm if small rolls each comprising a short length of tape are employed. Small rolls are used because they can be slipped through the small radial spaces between conductors and connectors.

The object of my invention is the provision of an im roved form of fluid stop joint for high tenslon electric cable in which the parts are so arranged that the individual conductors may be temporarily separated to-such a degree that relatively large rolls of insulating tape may be used, after which the conductors and their connectors are returned to their proper .respective positions'and secured in place in such manner as electively to separate the fluid inone cable section from that inanother..v -v

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto.

In the drawings which is illustrativeof my invention, Fig. 1 is a view artly in section and partly 1n elevation ci) a fluid stop jioint for a three-conductor oil filled cable;

1g. 2 1s a view illustrating the manner in which the partition is moved to one side and the conductors separated, and Fig. 3 is a diagrammatic view illustrating the separation of the conductors. j

5 indicates the lead sheath of a threecon ductor oil illed cable.v Only one cable end or section is shown, the opposite end being of similar construction. Within the sheath are three conductorsb, 7 and 8, each of which is covered with factory wound insulation 9 which ordinarily is of paper, butl other forms,

of insulating material mayl be used, 1() indicates a head which is connected to the cable sheath by a wiped soldered joint 1'1. The head supports one end of ka-tubular metal casing 12 which is made in two parts, the plane of division being perpendicular to the axis of the cable and midway between the heads 10. 13 indicates `a partition whichdivides' the casing into right and left hand chambers 14; and 15, aid chambers -being filled with oil or other i sulating fluid. The

cable sheath also contains oil or other insulating iiuid of the same character which has been carefully degasified.

In order Ato permit of the jointing operation, the cable havingbeen filled with oil prior to installationsemistop joints 16 are provided, one in each ofthe heads 10. These prevent any appreciable flow of Huid from the cable but will not`prevent a slow migration of thel fluid through ythe insulation on the conductors.

The partition 13 has as many openingsll'?, as Vthere are conductors and are equally spaced about the axis of the cable. The diameter of each opening is greater than the diameter of the body of tape insulation 18 which is applied by hand over each conductor joint. The tape for this purpose is supplied in rolls and may be varnished cambric or paper as desired. If 'aper is used it should be impregnated wit oil prior to 'being applied. 19 indicates a metal connector for connectin the adjacent ends voi? correspending con uctors. The connector is Covered with insulation 2O made of paper or equivalent material and impregnated with a phenolic condensation product so that the insulation as a whole is impervious to the oil contained in the casing; 21 indicates a metal thimble which is'hforced over the insulation 2O of each connector and which holds the insulation under compression at all times, so that no opportunity is afforded for oil to niigrate from one side of the-thimble to the other whether the parts be hotor cold. The thimble has a flange 22 which is larger than the openings 17 in the partition and when assembled an oil-proof gasket 23 is located between the shoulder and the partition. The thinible is screw-threaded to receive the clamping nut 24. .'lhe ends 27 of the conductors are soldered or otherwise secured to the connector.

The parts of the casing 12 are secured to the partition by a series of bolts 25 and packings 26 are provided between the out-turned flanges on the casing and the tlat side faces of the partition.

Surrounding the body of hand-applied tape 18 is an electrostatic shield 28 which may be in the form' of copper braid spirally wrapped thereon.

30 indicates a by-pass which by-passes oil from one side of the semi-stop joint 16 to the other. 31 indicates a pipe by means of which oil may be supplied both to the cable and to the joint casing.

In order to use long lengths of tape and therefore large diameter rolls the connectors and the cable ends must be separated radially. llie procedure is as follows:

The two ends of the cable sections are y brought into their proper positions, the connectors are temporarily assembled in the partition, the cable ends cut to their proper length and `soldered to the connectors. The

nuts 24 are then backed olf of the threads of the thimbles and slipped over the individual conductors to thepositions shown in Fig. 2. The partition is likewise moved to one side. rl`he respective ends of the cable are then pulled toward each other and at the same time the conductors spread from their normal posi tions, which are those indicated by the dotted lines 82. in Fig. 3 to the broken and dotted lines With the conductors and connectors thus widely separated and the partition 13 in its eXtreme left-hand position, the bodies of 'tape 18 are applied to the amount indicated in Fig. 1. After all the tape bodies have been applied and also the shields 28 the conductors are moved inward to their proper positions and the partition 13 is moved back to its proper place with each thimble 21 occupying its particular opening. The nuts 24 are then moved along the conductors and over the bodies of insulation 18 and screwed into place on the thimbles. After this is done, the

parts of the casing are slipped endwise into engagement with the partition and are bolted into place. The outer ends of the casing are then lsecured tothe heads by wiped soldered joints 34.

Certain of the operations of preparing the joints and evacuating the joint containing casing have been omitted as being unnecessary to an understanding or my invention, but it is to beunderstood that in these particulars any A suitable or well-known procedure may be followed.

By reasonlot1 my improved construction, rolls of tape of substantially larger diameter than/those employed heretofore may be used, with the result that the bodies of tape over the connectors and conductor ends will have fewer joints and will be much more dense than Where short pieces are used and hence the joints will be less liable to injury when in service due to the presence of voids.

What l claim as new and desire to secure by Letters Patent ot' the United States, is:

1. A stop joint for multi-conductor Huid lilled cable, comprising sheathed cable secf tions, each containing iiuid and separatelyinsulated conductors, a transverse metal partition having as many openings as there are conductors, each of said openings having a diameter greater than that of the insulation on a conductor to permit of the partition being temporarily moved to one side of its normal position, a connector which extends through each of the openings and is covered by insulation which is impervious to the fluid in the cable, a metal thirnble surrounding the insulation on each connector and' holding the same under compression at all times, means or securing the tliimbles within the openings in the partition and preventing the migration of fluid from one side thereof to the other, bodies' of insulating tape applied over the ends of each connector and the conductors united thereby and their insulations, and a divided casing united fluidtight to the cable slieaths at its outer ends and to the partition at the center.'

2. A stop joint for multi-conductor fluid iilled cable, comprising sheathed cable sec tions, each containing fluid and separately insulated conductors, a transverse metal partition which has as many openings as there are conductors, each of said openings having a diameter greater than that of the insulation on the conductor to permit of the partition being temporarily moved to one side of its normal position, an insulated. connector for each conductor which extends through one of the openings and is covered by insulation that is impervious to the fluid in the cable, a metal thimble surrounding the insulation on theconnector and 'holding the same under compression at all times, said thimble having a shoulderon one side of the partition and a screw thread on the other, threaded means for securing the thimbles in place, bodies of insulating tape applied over the ends of the connector and the insulation thereon and that on the conductors, the diameter 'of which is less than that of the corresponding opening in the partition, and a divided casing containing iluid and united magno;

at its outer ends to the cable sheaths and to 1 the partition at its center. l

3. A stop joint for multi-conductor fluid til-led cable, comprising sheathed cable sec- 5 tions, each containing Huid and separately insulated' conductors, a movable transverse metal partitionhaving as many spaced openings as there are conductors, an insulated connector for each conductor extending through 16 anopening in the artition, a thimble on each connector extending through -the partition which holds 'the insulation thereon under j compression at all times to prevent migration of the Huid, means for securing each thimble independently to the partition by a fluid-tight joint, taped insulation over the joint between each yconnector and the conduc-` tors secured' thereto, a casing comprising two tubular 'members having Han es on o posite I 20 sides of the partition, means 0r securing the flanges to t c partition, heads .at the ends of the casing members -united thereto and tothe cablev sheaths, semi-stop joints in the heads to prevent the free flow' of iud from the cable sections into the casing during the ljointing operation, anda by-pass around each of said semi-stop joints from the cabley sheath to the casing. ,V In witness whereof, I have hereunto set :so my hand this 21st dalyEof November, 1930.

` 4 ILES R L., PHILLIPS.

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