GB2189093A - Cable termination - Google Patents

Abstract

A method of terminating a power and/or telecommunications cable which is to be mounted in an offshore J- tube, includes replacing the end portion of at least one of the armour wires in the cable end with a tube (15 or 24) welded to the wire and into which thermo-elements or other sensors may be inserted after installation of the cable end. The remaining armour wires e.g. 20, 21 are welded to a steel retaining ring 22. <IMAGE>

Description

SPECIFICATION Cable Termination The present invention relates to a method for terminating a power and/or telecommunication cable and for mounting thermo-elements or other types of sensors in or on the cable termination.

Termination of cables in connection with offshore installations usually involves so-called J-tubes. A cable installed on the sea bed is brought into the lower horizontal part of the J-tube and follows a curve into the vertical riser part of the tube.

At least where power cables and composite cables are concerned it is required to monitor the cable temperature in the upper part of the J-tube, including the cable termination.

It has been common practice to tape thermosensors or thermo-elements to the cable surface and to bring the thermo element conductors to test equipment displaced from the cable termination itself. This process, in particular in connection with J-tubes, is rather cumbersome because the cable end will have to be lifted out of the upper end of the tube during the taping operation, whereupon it must be pulled back in again by a diver or a remote control vehicle for example.

An object of the present invention is to overcome the drawbacks of known methods.

According to the invention in its broadest aspect there is provided a method for terminating a power and/or a telecommunication cable having a cable core and one or more layers of armouring, characterised by terminating at least one of the armour wires a certain distance from the cable end and replacing it with tube means of substantially the same diameter, for the rest of the cable length so as to permit the installation within the tube of a sensor such as a thermo-element.

With this invention there is obtained a laboursaving method which provides an ideal termination and monitoring of the J-tube installed cable.

Embodiments ofthe invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a cable end attached to a pulling head, Figure 2 shows an interconnection of an armour wire with a tube, and Figure 3 shows the termination of armour wires.

In Figure 1 there is shown a cable end which is prepared for being pulled into a J-tube. A cable core 2 is sealed at its upper end 3 and inserted into a pulling head sleeve 4 which is secured to a pulling wire 5 by engaging means 6. The armour wires 7 of the cable, or at least a majority of these wires, are connected e.g. by welding, to a retaining ring 8 which is interconnected with the pulling head sleeve 4 by a threaded connection 9 or the like. The armour wire termination is made in the factory. A predetermined number of the armour wires are, however, cut a predetermined distance from the cable end and replaced with a corresponding number of tubes, as is illustrated in Figure 2. A typical cable has about 60 armour wires in an outer layer and some 40 wires in an inner layer, of which 4--8 are replaced with tubes as mentioned.

As shown in Figure 2 the tubes 15 should preferably have substantially the same diameter as the wires 16 and be welded or otherwise connected to these wires. The tubes therefore take up the same space in the cable construction as the armour wires and when the cable end has been installed within the J-tube, thermo-elements 17 may simply be inserted into the tubes 16. The tubes should preferabiy be made of the same material as the armour wires and be corrosion protected. One feature of the invention is that the thermo-elements may easily be pulled out for repair, control or replacement with other thermo-elements. The tubes may be filled with an inert fluid.

In Figure 3 two armour wires 20,21 are shown welded to a retaining ring 22 of steel which is thereafter interconnected with a pulling sleeve 23 by e.g. a threaded connection. One of the armour wires which is replaced with a thermo-elementtube is shown at 24. This tube is guided underneath the retaining ring 22 and it is extended into a pulling sleeve 23. Before pulling the cable end through the J-tube a guiding sleeve 25 is placed over the ring 22 to make a smooth surface. The sleeve 25 may be constituted by two half sleeves, not shown.

Whereas the inner diameter of the ring 22 is somewhat larger than the outer surface of the cable core 26, the ring 22 is fixed in a coaxial position relatively to the cable axis with the thermo-element tubes 24 arranged in the space 27 underneath the ring 22, by filling the space 27 with epoxy or the like.

An epoxy body 28 is also formed on the lower side of the ring to make a fluid-tight structure and a smooth gliding surface. After the cable end has been pulled through the J-tube the retaining ring 22 is mounted in its final position in e.g. a connector house wall or hang-off head arrangement 29. The pulling sleeve 23 will then be removed thereby revealing the cable core 26 as well as the thermoelement tubes 24 for installation.

Whereas it has been described that thermoelements may be inserted into tubes (15,24), it should be mentioned that also other types of sensors may be inserted into the tubes to measure or supervise strain, pressure also

CLAIMS 1. A method for terminating a power and/or a telecommunication cable having a cable core (2, 26) and one or more layers of armouring, characterised by terminating at least one of the armour wires (21, 22) a certain distance from the cable end and replacing it with tube means (15,24) of substantially the same diameter, for the rest of the cable length so as to permit the installation within the tube of a sensor such as a thermo-element.

2. A method according to claim 1, characterised by welding or soldering the tube means (15) to the armour wire (16).

3. A method according to claim 1 or 2, characterised by the making of the termination of the armour wire and the introductibn of the tube during the cable manufacturing process.

4. A terminated power and/or telecommunication

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Cable Termination The present invention relates to a method for terminating a power and/or telecommunication cable and for mounting thermo-elements or other types of sensors in or on the cable termination. Termination of cables in connection with offshore installations usually involves so-called J-tubes. A cable installed on the sea bed is brought into the lower horizontal part of the J-tube and follows a curve into the vertical riser part of the tube. At least where power cables and composite cables are concerned it is required to monitor the cable temperature in the upper part of the J-tube, including the cable termination. It has been common practice to tape thermosensors or thermo-elements to the cable surface and to bring the thermo element conductors to test equipment displaced from the cable termination itself. This process, in particular in connection with J-tubes, is rather cumbersome because the cable end will have to be lifted out of the upper end of the tube during the taping operation, whereupon it must be pulled back in again by a diver or a remote control vehicle for example. An object of the present invention is to overcome the drawbacks of known methods. According to the invention in its broadest aspect there is provided a method for terminating a power and/or a telecommunication cable having a cable core and one or more layers of armouring, characterised by terminating at least one of the armour wires a certain distance from the cable end and replacing it with tube means of substantially the same diameter, for the rest of the cable length so as to permit the installation within the tube of a sensor such as a thermo-element. With this invention there is obtained a laboursaving method which provides an ideal termination and monitoring of the J-tube installed cable. Embodiments ofthe invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a cable end attached to a pulling head, Figure 2 shows an interconnection of an armour wire with a tube, and Figure 3 shows the termination of armour wires. In Figure 1 there is shown a cable end which is prepared for being pulled into a J-tube. A cable core 2 is sealed at its upper end 3 and inserted into a pulling head sleeve 4 which is secured to a pulling wire 5 by engaging means 6. The armour wires 7 of the cable, or at least a majority of these wires, are connected e.g. by welding, to a retaining ring 8 which is interconnected with the pulling head sleeve 4 by a threaded connection 9 or the like. The armour wire termination is made in the factory. A predetermined number of the armour wires are, however, cut a predetermined distance from the cable end and replaced with a corresponding number of tubes, as is illustrated in Figure 2. A typical cable has about 60 armour wires in an outer layer and some 40 wires in an inner layer, of which 4--8 are replaced with tubes as mentioned. As shown in Figure 2 the tubes 15 should preferably have substantially the same diameter as the wires 16 and be welded or otherwise connected to these wires. The tubes therefore take up the same space in the cable construction as the armour wires and when the cable end has been installed within the J-tube, thermo-elements 17 may simply be inserted into the tubes 16. The tubes should preferabiy be made of the same material as the armour wires and be corrosion protected. One feature of the invention is that the thermo-elements may easily be pulled out for repair, control or replacement with other thermo-elements. The tubes may be filled with an inert fluid. In Figure 3 two armour wires 20,21 are shown welded to a retaining ring 22 of steel which is thereafter interconnected with a pulling sleeve 23 by e.g. a threaded connection. One of the armour wires which is replaced with a thermo-elementtube is shown at 24. This tube is guided underneath the retaining ring 22 and it is extended into a pulling sleeve 23. Before pulling the cable end through the J-tube a guiding sleeve 25 is placed over the ring 22 to make a smooth surface. The sleeve 25 may be constituted by two half sleeves, not shown. Whereas the inner diameter of the ring 22 is somewhat larger than the outer surface of the cable core 26, the ring 22 is fixed in a coaxial position relatively to the cable axis with the thermo-element tubes 24 arranged in the space 27 underneath the ring 22, by filling the space 27 with epoxy or the like. An epoxy body 28 is also formed on the lower side of the ring to make a fluid-tight structure and a smooth gliding surface. After the cable end has been pulled through the J-tube the retaining ring 22 is mounted in its final position in e.g. a connector house wall or hang-off head arrangement 29. The pulling sleeve 23 will then be removed thereby revealing the cable core 26 as well as the thermoelement tubes 24 for installation. Whereas it has been described that thermoelements may be inserted into tubes (15,24), it should be mentioned that also other types of sensors may be inserted into the tubes to measure or supervise strain, pressure also CLAIMS

1. A method for terminating a power and/or a telecommunication cable having a cable core (2, 26) and one or more layers of armouring, characterised by terminating at least one of the armour wires (21, 22) a certain distance from the cable end and replacing it with tube means (15,24) of substantially the same diameter, for the rest of the cable length so as to permit the installation within the tube of a sensor such as a thermo-element.

2. A method according to claim 1, characterised by welding or soldering the tube means (15) to the armour wire (16).

3. A method according to claim 1 or 2, characterised by the making of the termination of the armour wire and the introductibn of the tube during the cable manufacturing process.

4. A terminated power and/or telecommunication cable made by a method according to any previous claim.

5. A method for termination a power and/or telecommunication cable substantially as described with reference to the accompanying drawings.