Cable connector

Abstract: This invention relates to a method and means for interconnecting two insulated conductors in subsea environments. The interconnection is done by means of a subsea connector (1) including a conductor splice pin (6,7) and a splice insulation sleeve (8). A metal tube (9) is placed over the splice sleeve (8) and the conductor insulation (4,5) of both. The metal tube (9) is provided with partition means (12) for separating the two moldings (13,14).

Description: The present invention relates to a method and a connector related to electrical subsea connectors for interconnecting two electrical conductors having insulation sheaths. The method described in DE-A-1515547 belongs to interconnecting a submarine coaxial cable with a submarine repeater. The center conductor with its polyethylene insulation sheath is passed uninterrupted through a hollow metal tube which is used for interconnecting the outer conductor of the cable with a corresponding conductor of the repeater. The outer surface of the metal tube is corrugated so as to relieve the inner conductor of longitudinal stress when PE sheaths are welded to the PE conductor sheaths. It uses a metal tube which is provided at both ends with a sheath of polyethylene insulation, but it does not relate to a conductor joint. The known sleeve configuration is not suitable for interconnecting two conductors as proposed in this application. At high water pressures and with time it is difficult and nearly impossible to prevent water from entering joint compartments. One entrance to a point compartment is along the cable conductor underneath the conductor insulation. Remedies have been proposed for filling all spaces within a multifilament conductor and good effects have been obtained at low outer water pressure. In conventional joints the whole joint is covered with a common insulation sleeve. The problem is however to obtain sufficient bonding between the conductor insulations and the common insulation sleeve. When the two conductors to be joined have identical or compatible insulation sheaths, sufficient bonding will be obtained with a common joint sleeve. This is, however, not possible with one conductor having PE insulation and the other having rubber (e. g. Hypalon, Neoprene) insulation. One object of this invention is to improve subsea cable conductor joints. In particular the object is to improve an interconnection between the conductor insulation of an umbilical cable and the conductor insulation of the interfacing subsea equipment. The solution is characterized by the features of claim 1. With a conductor joint as defined there is obtained a unique waterproof connection between two insulated conductors, in particular betweeen conductors having sheaths of differnet insulation material. Above mentioned and other features and objects ot the present invention will clearly appear from the following detailed description of embodiments of the invention taken in conjunction with the drawing. In the figure is schematically illustrated a splice or joint 1 between two conductors 2 and 3 having insulation sheaths 4 and 5. The conductor insulation 4 is polyehtylene (PE) which is commonly used in umbilical cables and the conductor insulation 5 may be Hypalon, Neoprene or some other suitable rubber material which is used for wiring within offshore installations. As mentioned the main object is to provide a waterproof splice between a PE insulated conductor and a conductor with a rubber (e. g. Hypalon, Neoprene) insulation. A secondary object is to prevent water which may have entered the umbilical cable and the PE conductor insulation from entering the offshore installation. The two conductors 2 and 3 are therefore joined with a splice pin arrangement 6 and 7 so that water within the multifilament conductor 2 cannot penetrate to the multifilament conductor 3. The splice pin arrangement 6, 7 which is made of brass is covered by an insulator 8 of glass fiber reinforced epoxy material. Part of the outer surface of the pins 6 and 7 is provided with grooves 18, 19 in order to provide good bonding to the joint compounds. Over the insulator 8 there is arranged a tube 9 of metal such as stainless steel. The tube 9 is provided with corrugated outer surfaces 10, 11 in order to obtain good bonding and increase the bonding surface to the insulation material used in the joint. In the case where the two conductors have different conductor insulation, it may be necessary to pretreat the surface of the pin 6 and the surface 10 of the tube 9 up to the flanged section, differently from the treatment of the surface of the pin 7 and the surface 11 of the tube 9. Low density polyethylene is baked into the surfaces on the PE side of the tube and pin, whereas the rubber side of the tube/pin is treated with a two component primer compatible with the rubber. Application of jointing compounds may involve heating to different temperatures and one feature of the invention is therefore to separate the surfaces 10 and 11 by a partition 12. The partition 12 can have a U-shaped crossection including an airspace 15 between two partition walls 16, 17 for separating the two moldings 13, 14. The PE sheathed conductor 2, 4 is molded to the pin 6 and to the corresponding side of the tube 9 by using a compound 13 consisting of low density polyethylene which is applied at a temperature of some 180 °C for a period of some 10 minutes after a soaking period. The rubber sheathed conductor 3, 5 is molded to the pin 7 and to the corresponding side of the tube 9 by using a compound 14 consisting of a compatible rubber compound which is applied at a temperature of 150 - 170 °C for a period of 30 to 60 minutes. Then PE sheathed conductor 2, 4, which require higher molding temperature, is molded to the tube/pin 9, 6, 7 prior to molding of the rubber sheathed conductor 3, 5 in order to prevent melting of the insulation material. This problem is minimized by the unique design of the partition of the tube 9. With such a design of the joint, the insulation 4 of the conductor 2 may be bonded or molded to the pretreated surface 10 of the tube 9 with an insulation compound 13 which is compatible with the material 4 (and not with the insulation material 5). The arrangement can be similar on the other side of the joint where insulation compound 14 compatible with the insulation material 5 is bonded or molded to a pretreated surface 11 of the tube 9. The molding compounds 13 and 14 must also be capable of bonding to the pretreated surfaces of the splice pin arrangement 6, 7.

Claims: Method for interconnecting two electrical conductors (2, 3) having insulation sheaths (4, 5) of non-compatible insulation material such as PE and a rubber by means of a subsea connector, including the steps of joining the conductors (2, 3) within a conductor splice metal pin arrangement (6, 7), covering at least a part of the splice pin arrangement with an insulation sleeve (8), placing a metal tube (9) over the insulation sleeve (8) and molding the insulation sheaths (4, 5) of both conductors (2, 3) to opposite sides of the metal tube (9), by using individual molding compounds (13, 14), said molding compounds being compatible with the respective insulation sheaths. Method according to claim 1, characterized by pretreating the outer surfaces of the tube (9) and/or the pin arrangement (6, 7) to increase the bonding effect between the molding material and tube/pin. Method accroding to claim 1 or 2, characterized in that the PE sheathed conductor (2, 4) is molded by using a compound (13) consisting of low density polyethylene which is applied at a temperature of some 180 °C for a period of some 10 minutes. Method according to claim 1 of 2, characterized in that the rubber sheathed conductor (3, 5) is molded by using a compound (14) consisting of a compatible rubber compound which is applied at a temperature of 150 - 170 °C for a period of 30 to 60 mintes. Method according to claims 1 or 2, characterized in that the PE sheathed conductor (2, 4) is molded to the tube/pin (9, 6, 7) prior to molding of the rubber sheathed conductor (3, 5). Connector used in the method according to claim 1 to 5 above, characterized in that the metal tube (9) is provided with partition means (12) having a U-shaped crossection including a pace (15) between two partition walls (16, 17) for separating the two moldings (13, 14).

Inventors: SEKKELSTEN ULF ARNE, SEKKELSTEN, ULF ARNE
Applicants: ALCATEL STK AS, ALCATEL STK A/S
Application year: 1992
Main classification: H01R4
IPC codes: H02G15, H01R4