Abstract

A cable for transmitting electrical power at a voltage between 5 and 49 kV comprising a conductive cable core (12) and an insulation layer (16) for insulating the cable core (12), the insulation layer (16) comprising from 50 to 99.9% of cross linked polyethylene, and from 0.1 to 50% of ethylene-alkyl (meth)acrylate and/or ethylene vinyl acetate. The insulation layer is provided with a strippable outer semi conductive screen (18), which comprises from 20 to 80% by weight of a composition (A) of at least one copolymer selected from the group consisting of ethylene-alkyl (meth)acrylate carbon monoxides. The combination of materials in the insulator (16) and the semi conductive screen (18) provides for high water-tree resistance of the insulator (16) and strippability of the semi conductive screen (18).

IPC Classes  ?

• H01B 3/44 - Insulators or insulating bodies characterised by the insulating materialsSelection of materials for their insulating or dielectric properties mainly consisting of organic substances plasticsInsulators or insulating bodies characterised by the insulating materialsSelection of materials for their insulating or dielectric properties mainly consisting of organic substances resinsInsulators or insulating bodies characterised by the insulating materialsSelection of materials for their insulating or dielectric properties mainly consisting of organic substances waxes vinyl resinsInsulators or insulating bodies characterised by the insulating materialsSelection of materials for their insulating or dielectric properties mainly consisting of organic substances plasticsInsulators or insulating bodies characterised by the insulating materialsSelection of materials for their insulating or dielectric properties mainly consisting of organic substances resinsInsulators or insulating bodies characterised by the insulating materialsSelection of materials for their insulating or dielectric properties mainly consisting of organic substances waxes acrylic resins

Abstract

A sealing ring (14) is adapted to seal an annular gap (15) between a socket end (11 ) and a spigot end (12), the socket end having a circumferential groove (13) for receiving the sealing ring. Due to manufacturing tolerances, the radius of the groove (13) is between a minimum value R'min and a maximum value R'max, and the radial gap width of gap (15) is between a minimum value Tmin and a maximum value Tmax. The sealing ring (14) comprises a sealing element (16) and a holding element (17) which is connected thereto and which is more rigid than the sealing element (16) but is so elastically deformable as to allow insertion of the sealing ring (14) into the groove (13). The sealing element (16) comprises a first sealing part for sealing against the socket end (11 ) and a second sealing part (19) for sealing against the spigot end (12). The first sealing part has a neck portion (18a), which supports a radially outer head portion (18b), whose outer radius is slightly greater than R'max, the first sealing part (18) being, at the level of the neck portion (18a), bendable in the axial direction (P) along which the spigot end (12) is to be inserted into the socket end (11 ). The cross-section of the annular holding element (17) has a radial extent which is greater than 2 x Tmax.

IPC Classes  ?

• F16L 21/03 - Joints with sleeve or socket with elastic sealing rings between pipe and sleeve or between pipe and socket, e.g. with rolling or other prefabricated profiled rings placed in the socket before connection
• F16L 21/035 - Joints with sleeve or socket with elastic sealing rings between pipe and sleeve or between pipe and socket, e.g. with rolling or other prefabricated profiled rings placed around the spigot end before connection