GB1571679A - Terminating armoured cables - Google Patents

Description

(54) TERMINATING ARMOURED CABLES (71) We, STANDARD TELEPHONES AND CABLES LIMITED, a British Company of 190 Strand, London W.C.2, England, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to terminating cables, particularly arrangements for anchoring an armoured submarine cable to a submersible repeater housing.

Where an armoured submarine cable is joined to a pressure vessel or jointing chamber or similar piece of equipment, it has been usual practice to employ a tapered cone which is slid over the armour wires and the free ends of the armour wires are taken back over the outside of the cone and onto the surface of the cable for approximately 6 feet. These ends are held in place by a binding of further wires, and the armour wires are clamped to the tapered cone by means of a split outer armour clamp ring which is drawn by means of clamping bolts towards an anchor plate secured to the pressure vessel.

There are normally two sets of armour wires, lying in adiacent layers and our normal practice is to "make off" by means of the inner layer of wires, the outer layer of wires being cut-off outside the termination area. This was done to prevent the bulk of two sets of wire passing through the cone.

Furthermore one set of armour wires has sufficient tensile strength to securely anchor the cable during laying and recovery procedures. Nevertheless the termination remains the weakest point in a submarine cable telecommunications link particularly in shallow water where the majority if not all the cable will be armoured to protect it against fouling bv trawlers and the like.

According to the present invention there is provided a termination between a submarine cable having at least two layers of armour wires and a submersible housing, the housing having an anchor plate with an aperture therein through which the cable passes, the outer layer of armour wires being bent back over a tapered part and held to the anchor plate by a first armour wire clamp at the outside of the anchor plate and the inner layer of armour wires passing through the plate and being held to the anchor plate by a second armour wire clamp at the opposite side of the anchor plate.

In order that the invention can be clearly understood reference will now be made to the accompanying drawing which is a crosssection of part of a submarine cable repeater termination according to an embodiment of the invention.

Referring to the drawing a submersible repeater housing has an outer casing 1 formed by an extension piece which, in the lefthand direction of the drawling, is secured to the main repeater casing (not shown).

A domed end cover 2 is screwed at 3 to the extension piece 1 and locked by means of a locking worm screw 4. An anchor plate 5 has an annular rim 6 clamped between cooperating shoulders 7 and 8 of the extension pieces 1 and the end cover 2. An antirotation screw 9 prevents rotation of the anchor plate 5 relative to the casing of the repeater housing.

A submarine coaxial cable indicated generally by the reference numeral 10 has an inner layer of armour wires 11 surrounded by a jute or hemp or polypropylene bedding 12 on which is laid an outer layer of armour wires 13.

In order to prepare the cable for termination a tapered part in the form of a cone 15 is slipped over the outer laver of armour wires and the outer layer of wires bent back around the cone and alone the cable a distance of about 6 feet. This outer laver of armour wires is clamped bv an armour clamp 16 having a frusto-conical inner surface 17 which is drawn against the armour anchor plate 5 bv means of a nut 18 on a screw-thread stud 19 screwed into a hole 20 in the armour anchor plate. A lock nut 21 locks the first nut 18.

Thus the outer armour wires are clamped between the armour clamp and the cone and an outer binding 22 applied over the turned-back ends of the outer armour layer.

The armour clamp 16 comprises two semicircular parts 23 which are held together by an outer ring 24. Thus the armour clamp ring can be assembled onto the outer layer of armour wires relatively easily.

The inner layer of armour wires 11 extends through the aperture 5a in the armour anchor plate and round a smoothly curved rim 5b of the aperture. The wires extend radially up the inner face Sc of the anchor plate 5 and back around a first clamp ring 25 of a second armour clamp arrangement.

As shown the wires extend back around a second clamp ring 26 and are finally clamped by means of a nut 27 screwed on studs 28 and an annular washer 29. The faces of clamp rings 25 and 26 may be separated, knurled or treated with vinyl or epoxy adhesive onto which is sprinkled aluminium oxide or carborundum powder. The studs 28 are screwed into the same holes 20 as are the studs 19, but alternatively may also be screwed into separate holes. The armour clamp rings 25 and 26 have holes through them to accommodate the studs 28.

As an alternative it is envisaged that it would be satisfactory to simply clamp the inner armour wires 11 by means of the first clamp ring 25 and cut the wires off shortly after the position where they emerge from being clamped between the clamp ring 25 and the inside face Sc of the armour anchor plate 5. This is indicated for example at the point A.

Thus it can be seen that a simple and effective arrangement has been provided for clamping the inner anchor wires on one side of the armour anchor plate and the outer laver of armour wires on the other side of the armour anchor plate. With this arrangement we have found we can accommodate both layers of armour wires clamped within the existing repeater housing which we currently manufacture without modification except to the clamping parts and the anchor plate. The double-armoured cable termination can withstand a tensile load only equal to that of the UTS of the inner wires.

WHAT WE CLATM IS 1. A termination between a submarine cable having at least two layers of armour wires and a submersible housing, the housing having an anchor plate with an aperture therein through which the cable passes, the outer layer of armour wires being bent over a tapered part and held to the anchor plate by a first armour wire clamp at the outside of the anchor plate and the inner layer of armour wires passing through the plate and being held to the anchor plate by a second armour wire clamp at the opposite side of the anchor plate.

2. A termination according to claim 1 wherein the inner layer of armour wires extends along the inside of the anchor plate and an annular clamp ring clamps the inner layer of armour wires between itself and the inside of the anchor plate.

3. A termination according to claim 2 wherein the second armour wire clamp comprises a second annular clamp ring co-operating with the first ring to clamp between them the inner layer of armour wires.

4. A termination according to any preceding claim wherein the wires of the outer armour wire layer are thicker than those of the inner armour wire layer.

5. A termination as claimed in any preceding claim wherein the clamping pressure for each armour wire clamp is generated by means of a screw and nut arrangement, the screws being located in a common hole in the anchor plate.

6. A submarine cable/repeater termination substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.

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

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. Thus the outer armour wires are clamped between the armour clamp and the cone and an outer binding 22 applied over the turned-back ends of the outer armour layer. The armour clamp 16 comprises two semicircular parts 23 which are held together by an outer ring 24. Thus the armour clamp ring can be assembled onto the outer layer of armour wires relatively easily. The inner layer of armour wires 11 extends through the aperture 5a in the armour anchor plate and round a smoothly curved rim 5b of the aperture. The wires extend radially up the inner face Sc of the anchor plate 5 and back around a first clamp ring 25 of a second armour clamp arrangement. As shown the wires extend back around a second clamp ring 26 and are finally clamped by means of a nut 27 screwed on studs 28 and an annular washer 29. The faces of clamp rings 25 and 26 may be separated, knurled or treated with vinyl or epoxy adhesive onto which is sprinkled aluminium oxide or carborundum powder. The studs 28 are screwed into the same holes 20 as are the studs 19, but alternatively may also be screwed into separate holes. The armour clamp rings 25 and 26 have holes through them to accommodate the studs 28. As an alternative it is envisaged that it would be satisfactory to simply clamp the inner armour wires 11 by means of the first clamp ring 25 and cut the wires off shortly after the position where they emerge from being clamped between the clamp ring 25 and the inside face Sc of the armour anchor plate 5. This is indicated for example at the point A. Thus it can be seen that a simple and effective arrangement has been provided for clamping the inner anchor wires on one side of the armour anchor plate and the outer laver of armour wires on the other side of the armour anchor plate. With this arrangement we have found we can accommodate both layers of armour wires clamped within the existing repeater housing which we currently manufacture without modification except to the clamping parts and the anchor plate. The double-armoured cable termination can withstand a tensile load only equal to that of the UTS of the inner wires. WHAT WE CLATM IS

1. A termination between a submarine cable having at least two layers of armour wires and a submersible housing, the housing having an anchor plate with an aperture therein through which the cable passes, the outer layer of armour wires being bent over a tapered part and held to the anchor plate by a first armour wire clamp at the outside of the anchor plate and the inner layer of armour wires passing through the plate and being held to the anchor plate by a second armour wire clamp at the opposite side of the anchor plate.

2. A termination according to claim 1 wherein the inner layer of armour wires extends along the inside of the anchor plate and an annular clamp ring clamps the inner layer of armour wires between itself and the inside of the anchor plate.

3. A termination according to claim 2 wherein the second armour wire clamp comprises a second annular clamp ring co-operating with the first ring to clamp between them the inner layer of armour wires.

4. A termination according to any preceding claim wherein the wires of the outer armour wire layer are thicker than those of the inner armour wire layer.

5. A termination as claimed in any preceding claim wherein the clamping pressure for each armour wire clamp is generated by means of a screw and nut arrangement, the screws being located in a common hole in the anchor plate.

6. A submarine cable/repeater termination substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.