Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
ROCKING COLLAR AND UMBILICAL TERMINATION ASSEMBLY
Document Type and Number:
WIPO Patent Application WO/2012/001393
Kind Code:
A1
Abstract:
A rocking collar (10) for an umbilical termination assembly, said termination assembly comprising a plurality of the umbilical elements (2a, 2b) extending from an umbilical (1) and passing through a bulkhead plate (3), the collar (10) comprising at least a curved surface (12) and a spaced face, and wherein the collar (10) is able to fit around an umbilical element (2a, 2b) to align the longitudinal axis of the umbilical element with a plane of the spaced face (14) for subsequent conjoining, and wherein the curved surface (12) is able to abut the bulkhead plate. In this way, the present invention accepts the existence of umbilical element misalignments but provides a simple way of improving the conjoining and thus the quality of the load transfer between such umbilical elements and the bulkhead plate using rocking collars to provide more aligned conjoining surfaces.

Inventors:
HANSON, Anthony (9 Parkshiel, South Shiels, Tyne and Wear NE34 8BU, GB)
GRAYSON, Daniel (30 Honeysuckle Close, Hartlepool TS26 0RW, GB)
JAMESON, Christopher (19 Shrewsbury Drive, BackworthNewcastle, Upon Tyne NE27 0JS, GB)
Application Number:
GB2011/051187
Publication Date:
January 05, 2012
Filing Date:
June 24, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
TECHNIP FRANCE (6-8 Allée de L'Arche, Faubourg de L'ArcheZAC Danton, Courbevoie, F-92400, FR)
HANSON, Anthony (9 Parkshiel, South Shiels, Tyne and Wear NE34 8BU, GB)
GRAYSON, Daniel (30 Honeysuckle Close, Hartlepool TS26 0RW, GB)
JAMESON, Christopher (19 Shrewsbury Drive, BackworthNewcastle, Upon Tyne NE27 0JS, GB)
International Classes:
E21B17/02; E21B41/00; F16L1/26; F16L5/00; F16L39/00
Attorney, Agent or Firm:
MURGITROYD & COMPNAY (Scotland House, 165-169 Scotland StreetGlasgow, Strathclyde G5 8PL, GB)
Download PDF:
Claims:
Claims

1. A rocking collar for an umbilical termination assembly, said termination assembly comprising a plurality of the umbilical elements extending from an umbilical and passing through a bulkhead plate, the collar comprising at least a curved surface and a spaced face, and wherein the collar is able to fit around an umbilical element to align the longitudinal axis of the umbilical element with a plane of the spaced face for subsequent conjoining, and wherein the curved surface is able to abut the bulkhead plate.

2. A collar as claimed in claim 1 able to allow 90° alignment of the umbilical element axis with the spaced face. 3. A collar as claimed in any one of the preceding claims wherein the curved surface has a semicircle extent.

4. A collar as claimed in any one of the preceding claims wherein the spaced face is flat.

5. A collar as claimed in any one of the preceding claims wherein the curved surface meets the spaced face.

6. A collar as claimed in any one of the preceding claims wherein the collar is a semicircular cylinder.

7. A collar as claimed in any one of the preceding claims wherein the umbilical element and spaced face are subsequently conjoined by a conjoiner.

8. A collar as claimed in claim 7 wherein the conjoiner is one or more of the group comprising: welds and nuts.

9. A collar as claimed in any one of the preceding claims further including a medium port.

10. A collar as claimed in any one of the preceding claims wherein said collar is formed from a material compatible with the material of the umbilical element material, preferably steel.

11. A collar as claimed in any one of the preceding claims wherein the collar is rotatable, preferably freely rotatable, about the umbilical element to achieve maximum contact of the collar with the bulkhead plate. 12. A collar as claimed in any one of the preceding claims wherein the termination assembly comprises at least one misaligned umbilical element with the bulkhead plate.

13. An umbilical termination assembly comprising a plurality of the umbilical elements extending from an umbilical and passing through a bulkhead plate, and at least one, preferably a plurality of, rocking collars as defined in any one of claims 1 to 12, wherein the or each collar fits around an umbilical element beyond the bulkhead plate to align the longitudinal axis of the umbilical element with a plane of the spaced face of the collar for subsequent conjoining, and wherein the curved surface of the or each collar abuts the bulkhead plate.

14. A termination assembly as claimed in claim 13 wherein each said collar is subsequently welded to each said umbilical element at its spaced face.

15. A termination assembly as claimed in claim 14 wherein each said collar is further welded at its curved surface to the bulkhead plate. 16. A termination assembly as claimed in claim 13 wherein each said collar is subsequently conjoined to each said umbilical element at its spaced face using one or more nuts.

17. A termination assembly as claimed in any one of claims 13 to 16 further comprising one or more said collars to fit around an umbilical element prior to the bulkhead plate to align the longitudinal axis of the umbilical element with a plane of the spaced face of the collar for subsequent conjoining, and wherein the curved surface of the or each collar abuts the bulkhead plate.

18. A termination assembly as claimed in any one of claims 13 to 17 wherein at least one of the umbilical elements is misaligned with the bulkhead plate. 19. A method of forming an umbilical termination assembly comprising a plurality of umbilical elements extending from an umbilical and a bulkhead plate, comprising at least the steps of.

(a) passing the umbilical elements through the bulkhead plate;

(b) passing a rocking collar as defined in any one of claims 1 to 12 along at least one, optionally a plurality of, umbilical elements extending through the bulkhead plate;

(c) optionally rotating the or each collar against the bulkhead plate to maximise contact between the curved surface of the collar and the bulkhead plate; and (d) conjoining the umbilical element to the spaced face of the collar.

20. A method of improving the load transfer between a misaligned umbilical element and a bulkhead plate in an umbilical termination assembly, comprising at least the steps of:

(a) passing a rocking collar as defined in any one of claims 1 to 12 along the umbilical element after it extends through the bulkhead plate;

(b) optionally rotating the collar against the bulkhead plate to maximise contact between the curved surface of the collar and the bulkhead plate; and

(c) conjoining the umbilical element to the spaced face of the collar.

21. A method a claimed in Claim 19 or claim 20 wherein the conjoining comprises: welding, using nuts, or both.

22. A method as claimed in any one of claims 19-21 further comprising the step of:

(e) welding the curved surface of the or each collar to the bulkhead plate.

23. A method as claimed in claim 21 or claim 22 comprising automatic welding of the collar to an umbilical element, to the bulkhead plate, or both.

Description:
Rocking collar and Umbilical Termination Assembly The present invention relates to a rocking collar and an umbilical termination assembly using such collars, particularly but not exclusively for a steel tube umbilical termination, and to a method of forming an umbilical termination assembly using such collars. Generally, an umbilical, especially for subsea use, comprises a group of one or more types of elongate active umbilical elements, such as electrical cables, optical fibre cables and fluid conveying conduits, cabled together for flexibility and over-sheathed and/or armoured for mechanical strength. Umbilicals are typically used for transmitting power, signals and fluids (for example for fluid injection, hydraulic power, gas release, etc.), especially to and from a subsea installation. The main fluid conduits used for manufacturing umbilical are thermoplastic hoses and steel tubes. API (American Petroleum Institute) 17E "Specification for Subsea Umbilicals", third edition, July 2003, provides standards for the design and

manufacture of such umbilicals.

A steel tube umbilical is defined as an umbilical wherein all or most of the umbilical elements which compose the umbilical are steel tubes. The steel tubes and the other elongate umbilical elements that make up the umbilical are grouped together and wound in a helical pattern. Examples of steel tube umbilicals are disclosed in US6472614, W093/17176 and GB2316990. Steel tubes are not permeable to gases. They are also able to resist installation and in-service axial loads, and high external collapse pressures. Thus, such an umbilical, with judicious design, is better able to withstand axial loads without requiring the addition of tensile armour layers. It is also possible to increase further axial resistance by adding internal steel or composite rods inside the bundle (for example see US6472614 and WO2005/124213). US6102077 discloses an elongate subsea structure combining the functions of a flexible pipe and a general utility umbilical as described above; such structures are also generally defined herein as an umbilical. This structure comprises a large diameter central flexible pipe used as a production line for conveying oil or gas, and a plurality of small diameter peripheral pipes arrayed in helical or S/Z manner around the central flexible pipe, said peripheral pipes being used as service or control lines for fluid injection, gas lift injection, hydraulic power or gas release. Such structures are known under the names ISU ® "Integrated Subsea

Umbilical" and IPB "Integrated Production Bundle". The central flexible pipe generally complies with the standard API 17J "Specification for Unbonded Flexible Pipe", second edition, November 1999. The small diameter peripheral pipes of ISU ® and IPB are generally steel tubes.

The invention aims at solving the problem of better securing at least some of the umbilical elements, especially the load bearing elements, at at least one of the umbilical terminations as part of the umbilical termination assembly.

A known method of umbilical termination is illustrated in the accompanying Figure 1. The method comprises welding the steel tubes 2a, 2b (or steel rods) forming part of the umbilical 1 directly to a steel bulkhead plate 3 having through holes 8a, 8b through which the steel tubes 2a, b pass, and which is mechanically attached to the overall termination 4. Figure 1 shows welds 6a, 6b. The interior cavity of the termination 4 is filled with a compression resistant resin 5, gravity poured, through a filler hole situated at the top of the termination 4.

In this way, the steel tubes 2a 2b are directly welded to the bulkhead plate 3. The load transfer from the umbilical 1 (the 'pull out load F' due to the suspended weight of the riser umbilical) to the bulkhead plate 3 (which is usually attached onto a floating production unit) is made mainly via the steel tubes 2a 2b and the welds 6a 6b. The function of the resin 5 is to prevent the radial movements of the tubes inside the termination. The resin 5 is not able to prevent the tubes 2a, b from sliding and being pulled out, so that the function of the welds 6a 6b is to transfer most of the pulling load from the steel tubes 2a 2b to the bulkhead plate 3. Thus, the welds 6a, b are very critical for the reliability and the safety of the termination 4. However, it is difficult to achieve good quality welds when the tube axis is not perfectly perpendicular to the bulkhead plate 3. In Figure 1 , the tube 2b is aligned, but the tube 2a is in misalignment. Unfortunately, tube misalignments cannot be avoided, and the tubes cannot easily be

'straightened'. Indeed, removing such misalignments would make the termination assembly much more difficult to mount. An umbilical may comprise a very large number of tubes or rods, some of them being very stiff. As these tubes are usually also helically (or in S-Z) wound, they would all have to be perfectly straightened up in the termination to correct the misalignments, which would be very difficult and time consuming.

Tube misalignments present at least two main drawbacks to the welding process. Firstly, because of the misalignment, each relevant through hole 8a has to be machined with a significantly larger diameter than the outer diameter of its tube (2a), but this leads to an increasing, and increasingly undesired, gap thereinbetween, in particular a significant gap which affects the quality of the subsequent weld 6a and its load transfer reliability.

Secondly, misalignments are not compatible with the use of automatic welding processes such as orbital welding. Automatic welding machines are clamped onto the tube and their welding head is guided in rotation around the tube axis. Therefore, if the tube axis is not perpendicular to the bulkhead plate plane, the welding head will not follow the intersection of the tube and the plane. This leads to an uneven weld of lower quality and lower reliability.

Thus, any even slight misalignment of the tubes 2a, b and the bulkhead plate 3 leads to unbalanced loading or load transfer thereinbetween, and thus potential weak spots or areas in the welding therebetween. This is especially when the load-bearing nature of some of the steel tubes is very high. Trying to align a heavy bulkhead plate simultaneously against 20-30 tubes is a demanding and difficult task, generally requiring significant manual input, especially to weld all the separate tubes perfectly whilst maintaining best alignment thereinbetween.

One object of the present invention is to improve the load transfer between an umbilical and a bulkhead plate without removing the misalignments between tubes and the bulkhead plate. According to a first aspect of the present invention there is provided a rocking collar for an umbilical termination assembly, said termination assembly comprising a plurality of the umbilical elements extending from an umbilical and passing through a bulkhead plate, the collar comprising at least a curved surface and a spaced face, and wherein the collar is able to fit around an umbilical element to align the longitudinal axis of the umbilical element with a plane of the spaced face for subsequent conjoining, and wherein the curved surface is able to abut the bulkhead plate. This allows alignment of the longitudinal axis of the umbilical element with the conjoining surface.

In this way, the present invention accepts the existence of umbilical element misalignments but provides a simple way of improving the conjoining and thus the quality of the load transfer between such umbilical elements and the bulkhead plate using rocking collars to provide more aligned conjoining surfaces.

In the present application, an axis and a surface are said to be aligned when the axis is parallel to the surface normal at the crossing point between the axis and the surface. In the case where the surface is a plane, the axis and the plane are said to be aligned when they are perpendicular.

Generally, the umbilical having the termination assembly or assemblies has a number of elongate umbilical elements, optionally one or more being steel tubes. A common umbilical for use in sub-sea situations involves a number of steel tubes, one or more of which is also load-bearing and intended to assist with the actual load-bearing of the umbilical between its terminations. Where such umbilicals are >500m in length, and possibly >1000m, >2000m or even >3000m in length, the skilled man is aware of the increasingly significant axial loading on the umbilical, and thus the need for ensuring best possible transfer of such loading at the umbilical terminations, generally through each termination assembly.

Other kinds of umbilical elements include one or more of the group comprising: steel rods, steel ropes, high strength cables, composite rods, composites ropes, composite tubes and reinforced hoses; any

combination of which, optionally in combination with one or more steel tubes, may simultaneously pass through a bulkhead plate in a termination assembly.

One, some or all of the umbilical elements may extend directly from the umbilical and through the bulkhead plate. One, some or all of the umbilical elements may be extended from the umbilical to pass through the bulkhead plate. Such extension(s) may be by the addition of one or more end pieces, generally having the same inner and/or outer diameter, and optionally adapted to assist the conjoining of the umbilical element with a rocking collar as part of the present invention, and/or to assist load transfer between the umbilical element and the bulkhead plate. Such end pieces, extensions of sleeves may be adapted by the addition of one or more threaded portions for conjoining with threaded nuts and the like.

The bulkhead plate is commonly a single machined plate intended to provide mechanical attachment of at least some of the elongate umbilical elements in the umbilical to the termination assembly, typically at least the load-bearing umbilical elements. Generally, the bulkhead plate is wholly or substantially steel.

A rocking collar of the present invention may comprise any suitable shape, design, size or configuration, and be formed of any suitable material or combination of materials. One suitable material is steel. Preferably, the rocking collar is formed from the same, a correspondingly similar, or an otherwise compatible, material to that of the bulkhead plate and/or at least a number of the umbilical elements. An umbilical termination assembly may comprise a number of rocking collars which may be the same of different. Different rocking collars may be adapted to suit different umbilical elements.

A rocking collar may comprise two or more portions intended to be conjoined in use, and able to fit around an umbilical element by any suitable configuration.

Preferably, the rocking collar is, or is formed as, an integral piece and unit. A rocking collar may comprise at least one aperture extending from the curved surface to the spaced face, which aperture corresponds to the outer diameter of a relevant umbilical element, with a tolerance

thereinbetween to allow passage or journaling of the rocking collar along the umbilical element, generally from its free end. The free end of an umbilical element generally extends a short distance beyond the bulkhead plate during assembly.

According to one embodiment of the present invention, the curved surface of the rocking collar has a semi-circular extent to provide a semi-circular surface. The semi-circular extent may extend partially or fully around one side of the collar.

According to another embodiment of the present invention, the spaced face is wholly or substantially flat.

According to another embodiment of the present invention, the rocking collar has a raised collar portion extending from the spaced face around the umbilical element location, generally the aperture through the collar therefor. A rocking collar may comprise one or more sides or other faces or face portions between the curved surface and the spaced face. Preferably, the curved surface meets the spaced face. According to a preferred embodiment of the present invention, the rocking collar is a semi-circular cylinder, generally comprising a curved surface, a wholly or substantially flat or planer spaced face, and two end faces, with a perpendicular umbilical element aperture. A rocking collar may include one or more further portions or parts, such as a medium port for the provision of a fluid such as an anticorrosion medium into the rocking collar in use.

Preferably, the rocking collar is able to allow 90° or perpendicular alignment of the longitudinal axis of the umbilical element with its spaced face, so as to provide an even load-bearing arrangement therebetween once conjoined. Such alignment may not be exactly 90°, and the skilled man is aware of the angle being able to be wholly or substantially 90°. According to another embodiment of the present invention, the rocking collar is rotatable, preferably freely rotatable, about the umbilical element to achieve maximum contact of the collar with the bulkhead plate. For example, the collar could be slid along the umbilical element until its curved surface is in contact with the bulkhead plate, followed by rotating the collar around the element axis while maintaining the contact until a stable and optimized position has been found. Then, a positioning conjoin such as a weld could be applied, possibly having no load bearing function, but to maintain the collar in optimized position prior to completing a full or retention weld or other conjoining. According to one embodiment of the present invention, the umbilical element and spaced face are subsequently conjoined by a conjoiner. The conjoiner is preferably one or more of the group comprising: welds and nuts, as well as bonds or bonding, crimps or crimping and other mechanical locking means.

A rocking collar of the present invention is for use on the end or ends of umbilical elements beyond the bulkhead plate, that is on the far or distal side of the bulkhead plate from the umbilical, typically being one 'side' of an umbilical termination assembly.

One or more rocking collars of the present invention may also be for use in a similar manner on the end or ends of umbilical element(s) prior to passing through the bulkhead plate, that is on the near or nearest side of the bulkhead plate from the umbilical. Such rocking collar(s) can provide a similar function of improving the quality of the load transfer between such umbilical elements and the bulkhead plate (through more aligned conjoining surfaces) prior to and/or during the setting and/or hardening of any filler in the terminal assembly such as epoxy filling that can be used to 'fix' the internal arrangement within the terminal assembly, and/or during the conjoining of one or more rocking collars on the far side of the bulkhead plate as described hereinabove.

The present invention therefore includes a rocking collar as defined hereinabove wherein the termination assembly comprises at least one misaligned umbilical element with the bulkhead plate.

According to a second aspect to the present invention, there is provided umbilical termination assembly comprising a plurality of the umbilical elements extending from an umbilical and passing through a bulkhead plate, and at least one, preferably a plurality of, rocking collars as defined hereinabove, wherein each collar fits around an umbilical element beyond the bullhead plate to align the longitudinal axis of the umbilical element with a plane of the spaced face of the collar for subsequent conjoining, and wherein the curved surface of the or each collar abuts the bulkhead plate.

Preferably, the termination assembly is such that each said collar is fitted around an umbilical element and is subsequently welded there to at its spaced face.

According to another embodiment of the present invention, the termination assembly is such that each said collar fitted around an umbilical element is further welded at its curved surface to the bulkhead plate.

Alternatively and/or additionally, the termination assembly is such that each said collar is fitted around an umbilical element and is subsequently conjoined to each said umbilical element at its spaced face using one or more nuts.

According to another embodiment of the present invention, the termination assembly further comprises one or more said collars to fit around an umbilical element prior to the bulkhead plate to align the longitudinal axis of the umbilical element with a plane of the spaced face of the collar for subsequent conjoining, and wherein the curved surface of the or each collar abuts the bulkhead plate.

The termination assembly as defined herein may include wherein at least one of the umbilical elements is misaligned with the bulkhead plate. According to another aspect of the present invention, there is provided a method of forming an umbilical termination assembly comprising a plurality of umbilical elements extending from an umbilical and a bulkhead plate, comprising at least the steps of:

(a) passing the umbilical elements through the bulkhead plate;

(b) passing a rocking collar as defined herein above along at least one, optionally a plurality of, umbilical elements extending through the bulkhead plate;

(c) optionally rotating the or each collar against the bulkhead plate to maximise contact between the curved surface of the collar and the bulkhead plate; and

(d) welding the umbilical element to the spaced face of the collar. According to another aspect of the present invention, there is provided a method of improving the load transfer between a misaligned umbilical element in an umbilical termination assembly and a bulkhead plate, comprising at least the steps of:

(a) passing a rocking collar as defined herein above along the umbilical element after it extends through the bulkhead plate;

(b) optionally rotating the collar against the bulkhead plate to maximise contact between the curved surface of the collar and the bulkhead plate; and

(c) conjoining the umbilical element to the spaced face of the collar.

The conjoining may comprise welding, using nuts, bonds, crimps, or a combination of same.

Preferably, the aligning of the umbilical element axis with the spaced face is perpendicular or at 90°. According to a further embodiment of the present invention, the or each method further comprises the step of:

(e) welding the curved surface of the collar to the bulkhead plate.

By ensuring that there is best alignment of the umbilical element axis and the spaced face, and by using welding to conjoin same, the present invention can also allow automatic welding of the collar to the elongate elements, bulkhead plate, or both. That is, with the assurity of the alignment between the umbilical element axis and at least the spaced face of the collar, automatic welding such as that provided by known welding machines, can continue the assembly of the termination assembly, rather than requiring constant and vigilant manual attention by one or more persons skilled in the art to look at the umbilical element and bulkhead plate alignment during each welding process.

Thus, according to another embodiment of the present invention, the or each method comprises automatic welding of the collar to the umbilical elements, to the bulkhead plate, or both.

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings in which:

Fig. 1 is a longitudinal sectional view through a prior art umbilical termination assembly;

Fig. 2 is a perspective view through a rocking collar according to one embodiment of the present invention; Fig. 3 is a schematic longitudinal sectional view of a rocking collar, tube and bulkhead plate of a first umbilical termination assembly according to the present invention; Figures 4a and 4b are side cross-sectional and front views respectively of area A in Figure 3;

Fig. 5 is a perspective view of the rocking collar in situ according to a further embodiment of the invention;

Fig. 6 is a perspective view of an umbilical termination assembly according to a further embodiment of the present invention;

Figure 7 is a schematic longitudinal sectional view of a rocking collar, tube and bulkhead plate of a second umbilical termination assembly according to the present invention.

Referring to the drawings, Figure 1 , as described above, shows a prior art umbilical termination comprising a plurality, the two steel tubes 2a, 2b being two examples only, extending from an umbilical 1 and passing through two through holes 8a,8b in a steel bulkhead plate 3.

There can be seen from Figure 1 an example of how a number of steel tubes need to pass through the bulkhead plate 3 simultaneously, therefore requiring the exact positioning of the bulkhead plate 3 prior to welding of the steel tubes 2 thereto. The conventional operations of locating, aligning and maintaining alignment during welding of the steel tubes to the bulkhead plate 3 requires significant manual input and labour in order to try and achieve the possible continuous alignment

thereinbetween. This is to achieve the best possible and most even load- transfer between the steel tubes and the bulkhead plate 3, and therefore to achieve the best possible and most even load-transfer between the umbilical 1 and the umbilical termination as a whole. As such an alignment is not always possible, or may be expected/believed but not actually achieved at the end of all the welding processes, and knowing the increasing load-bearing nature of such steel tubes due to the increasing lengths of umbilicals now being used (possibly >3000m), there have been developments in the nature of the resin 5 added to the interior cavity of the termination 4, such as that shown in Figure 1. This is to provide some (and indeed an increasing amount of) reliance on the load transfer ability of the resin in the light of known possible problems with the attachments of umbilical elements such as steel tubes to bulkhead plates in the art. However, this now increasingly places reliance on the nature of the resin which is not preferred in practice.

Figure 2 shows a rocking collar 10 according to one embodiment of the present invention, for an umbilical termination assembly such as that shown in Figure 1.

The collar 10 comprises a curved surface 12 and a spaced face being a weld face 14 for the use of the collar 10 shown in Figure 3. The curved surface 12 has a semi-circular extent and meets the weld face 14 along edges 15. The weld face 14 is generally flat, such that the general nature of the curved surface 12 and the weld face 14 is to make the collar a semicircular cylinder.

The collar 10 has a first aperture 18 extending from the curved surface 12 to the weld face 14, which aperture 18 corresponds to the outer diameter of a relevant umbilical element such as a steel tube 2 shown in Figure 1 . There is a tolerance between the aperture 8 and the outer diameter of a relevant umbilical element to allow the provision or journaling of the collar 10 along the umbilical element. The collar 10 further includes a raised collar portion 20 extending from the weld face 14 around the umbilical element location being the aperture 18. The raised collar portion 20 assists the welding of the collar 10 to an umbilical element. Figure 2 also shows the collar 10 having a medium port 21 for the provision of a fluid into the collar 10, such as an anticorrosion medium that can be injected into (and maintained in) the collar 10 in use.

Figure 3 shows in a simplified and schematic view an arrangement of the rocking collar 10 in use around two umbilical elements such as upper and lower steel tubes 2a, 2b and against a bulkhead plate 3 as shown in Figure 1 to provide a first termination assembly 4a according to the present invention. The rocking collars 10 are useable even where an umbilical element is not misaligned with the bulkhead plate 3. Thus, Figure 1 shows that although the lower tube 2b is not misaligned through through hole 8b, a rocking collar 10 is still useable, and may assist in an automatic welding process where a number of collars 10 are used elsewhere around the bulkhead plate 3.

In Figure 3, the juxtaposition of the upper steel tube 2a is deliberately shown in misalignment, (i.e. not at 90 o) with the bulkhead plate 3 in an exaggerated manner. Nevertheless, it can be recognised that direct welding of the upper steel tube 2a and the bulkhead plate 3 as shown in Figure 3 would result in an uneven load transfer between the upper steel tube 2a and the bulkhead plate 3, which creates a potential weak spot or area in the welding thereinbetween that could promote failure, potentially catastrophic failure, especially if a number of the alignments of the load- bearing umbilical elements of the umbilical and the bulkhead plate are similarly incorrect. It is for this reason that more reliance is being placed in the art on the nature and load-transfer ability of the resin 5 added into the umbilical termination cavity of Figure 1 . Figure 3 shows the rocking collar 0 of the present invention being able to fit around the upper steel tube 2a, with its curved surface 14 able to abut the bulkhead plate 3. Thus, there is desired alignment of the longitudinal axis (Z) of the umbilical element with the weld face 14. Once the contact is optimized, a positioning weld 22 can optionally be provided between the collar 10 and the bulkhead plate 3 to maintain the collar 10 in its optimized position until a retention weld 24 between the weld surface 4 and the upper tube 2a has been completed. The retention weld 24 can now be easily carried out with an automatic orbital welding machine because the plane of the weld face 14 is by construction correctly perpendicular to the upper tube axis Z. Moreover, the gap between the upper tube 2a and the rocking collar 10 is much reduced compared to the enlarged through hole 8a required to allow passage of the misaligned upper tube 2a through the bulkhead plate 3 at an angle. Indeed the aperture 18 machined in the rocking collar 10 is preferably a cylindrical hole whose axis is correctly perpendicular to the plane of the weld face 14, and the internal diameter of which fits the outer diameter of the upper tube 2a with good tolerance. This also avoids or minimizes any bending stresses that may otherwise occur between the misaligned upper tube 2a and the bulkhead plate 3.

Figures 4a and 4b show in greater detail how it is also preferred to maximize contact or contact surface 28 between the curved surface 12 of the rocking collar 10 and the plane surface 9 of the bulkhead plate 3. The larger the contact surface 28, the larger the load that can be transferred without damaging the rocking collar 10 or the bulkhead plate 3 (as local compressive stresses in the contact area have to be maintained at acceptable levels depending on the steel properties). Thus, the surface 12 is curved in order to achieve a good contact surface.

The best mode to achieve this contact/abutment with the bulkhead plate 3 is to use a cylindrical curved surface 12. In a preferred embodiment, the axis of this cylindrical surface (X) is perpendicular to axis of the aperture 18 (Z) (and therefore also to the axis of the tube 2).

The diameter of the cylindrical surface 12 of the rocking collar 10 is preferably larger than the outer diameter of the tube 2a.

As a first alternative, the curved surface is spherical, the centre of the sphere being on the axis on the aperture 8, and the diameter of the sphere being larger than the outer diameter of the tube. To maximize the contact surface 28 between the rocking collar 10 and the bulkhead plate 3 (after sliding the collar 10 along the tube 2a until the curved surface 12 and the bulkhead plane 9 are in contact), and the collar 10 is rotated around the upper tube 2a (or the aperture 18) while maintaining the contact with the bulkhead plate 3, until a stable and optimized position has been found thereinbetween. In the example shown in Figure 4b, there are two optimized angular positions at 180° from each other. In the optimized positions, the axis X of the curved surface 12 is perpendicular to the plane defined by both the axis Z of the upper tube 2a and the axis Y of the through hole 8a.

Figure 5 shows a perspective view of the rocking collar 10 in-situ and welded by a first (positioning) weld 22 to the bulkhead plate 3, and by a second (retaining) weld 24 to an umbilical element such as upper steel tube 2a.

Figure 6 shows a perspective view of an umbilical termination assembly according to another embodiment of the present invention, comprising a plurality of umbilical elements 30 extending from an umbilical (not shown) and passing through a bulkhead plate 32, and a plurality of rocking collars 34 such as that shown in Figure 2. Each collar 34 is fitted around an umbilical element 30, and has the correct alignment of the longitudinal axis of the umbilical element 30 with the weld face of the collar 34 prior to welding thereinbetween. Figure 7 shows in a simplified and schematic view an arrangement of rocking collars 30 similar to the rocking collar shown in Figure 2 in use around two umbilical elements such as upper and lower steel tubes 32a, 32b and against a bulkhead plate 3 as shown in Figure 1 to provide a second termination assembly 4b according to the present invention.

Similar to Figure 2, the rocking collars 30a, 30b are useable even where an umbilical element is not misaligned with the bulkhead plate 3. Thus, Figure 7 shows that although the upper tube 32a is not misaligned through hole 38a, a rocking collar 30a is still useable, and may assist in an automatic welding process where a number of collars 30b are used elsewhere around the bulkhead plate 3.

In Figure 7, the juxtaposition of the lower steel tube 32b is deliberately shown in misalignment, (i.e. not at 90 o) with the bulkhead plate 3 in an exaggerated manner. Nevertheless, it can be recognised that direct joining of the lower steel tube 32b and the bulkhead plate 3 as shown in Figure 3 would result in an uneven load transfer between them that could promote failure, potentially catastrophic failure, especially if a number of the alignments of the load-bearing umbilical elements of the umbilical and the bulkhead plate are similarly incorrect. It is for this reason that more reliance is being placed in the art on the nature and load-transfer ability of resin 35 added into the umbilical termination cavity of Figure 7. Figure 7 shows one rocking collar 30b of the present invention being able to fit around the lower steel tube 32b, with its curved surface 12 able to abut the bulkhead plate 3. Thus, there is desired alignment of the longitudinal axis (Z) of the umbilical element with the spaced face 14. Once the contact is optimized, one or more nuts 40 can optionally be provided against the collar 30b to maintain it in its optimized position against the bulkhead plate 3 and to transfer tensile load therebetween through the flat surfaces of the nuts and the planer surface of the spaced face 14 of the rocking collar 30b. As above, this also avoids or minimizes any bending stresses that may otherwise occur between the misaligned tube 32b and the bulkhead plate 3.

Figure 7 also shows the addition of a threaded sleeve 42 to the end of each of the upper and lower tubes 32a, 32b (through welds 44) to allow retention of the tubes 32a, 32b with the nuts 40. Figure 7 also shows the application of a rocking collar 30c around the lower tube 32b on the near side of the bulkhead plate 3, and its fixing to the sleeve 42 via another nut 40, prior to conjoining the rocking collar 30b on the far side of the bulkhead plate 3 as described hereinabove. The bulkhead plate 3 is strongly tightened between both collars 30b, 30c which maintains the alignment of the lower tube 32b with the bulkhead plate 3 during the setting and hardening of the epoxy resin 35 filler in the terminal assembly 4b.

The present invention provides elements and a system which provides better assurance of the load transfer between one or more misaligned umbilical elements in an umbilical, in particular those umbilical elements intended to be load bearing, and the termination assembly, in particular the bulkhead plate. With better or more assured load transfer ability, less reliance may be required to be placed on any other load transfer medium, means or assembly in the termination assembly, such as the resin or other filler material provided in the general cavity of the termination assembly. Further benefits and advantages of the present invention are described herein.

Various modifications and variations to the described embodiments of the invention will be apparent to those skilled in the art without departing from the scope of the invention as defined in the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments.