HOSE ASSEMBLY FOR UNDERWATER USE

Abstract

A hose assembly for use underwater or in a wet or severe environment which includes a hose having an interior space and extending in a longitudinal direction. A first termination assembly terminates the hose at a first end and a second termination assembly terminates the hose at a second end. A signal carrier is disposed in the interior space of the hose and extends between the first and second termination assemblies. A strength member is disposed in the interior space of the hose.

Claims

1. A hose assembly for use underwater or in a wet or severe environment, comprising: a hose having an interior space and extending in a longitudinal direction; a first termination assembly terminating the hose at a first end and a second termination assembly terminating the hose at a second end; a signal carrier disposed in the interior space of the hose and extending between the first and second termination assemblies; and a strength member disposed in the interior space of the hose; wherein the strength member is mounted to the first termination assembly and to the second termination assembly and extends between the first termination assembly and the second termination assembly through the interior space of the hose, the strength member being configured to at least partly bear tensile stress applied to the hose assembly.

2. The hose assembly according to claim 1, wherein the strength member comprises a metal cable, a steel cable, or a strand of carbon composite material.

3. The hose assembly according to claim 1, wherein the signal carrier comprises at least one optical fiber, an optical fiber strand, or an optical fiber ribbon.

4. The hose assembly according to claim 1, wherein the interior space of the hose is filled with a substantially incompressible medium, a liquid, a gel, a dielectric liquid, an oil, or a silicone oil.

5. The hose assembly according to claim 1, further comprising: a protection tube disposed in the interior space of the hose, wherein the signal carrier extends inside the protection tube.

6. The hose assembly to claim 5, wherein the protection tube has at least one opening, or plural openings, to allow a flow of a medium that is present in the interior space of the hose into and out of the protection tube.

7. The hose assembly according to claim 5, wherein the first and/or second termination assembly comprises a through hole through which the protection tube and the signal carrier extend.

8. The hose assembly according to claim 1, wherein the strength member is configured to limit the expansion of the hose in a longitudinal direction upon application of a tensile stress to a value that is smaller than 2% of the hose's length in the longitudinal direction.

9. The hose assembly according to claim 1, wherein at a first end, the strength member is provided with a first end fitting having an outer diameter larger than the diameter of the strength member, wherein the first termination assembly comprises a termination block in which the first end fitting is retained such that a tensile force applied to the strength member is transferred to the termination block of the first termination assembly.

10. The hose assembly according to claim 9, wherein the termination block of the first termination assembly has a through hole leading through the termination block into the interior space of the hose, wherein the strength member extends through the through-hole into the interior space of the hose, wherein the diameter of the through hole is at least partly smaller than the diameter of the first end fitting so that the first end fitting is retained in the termination block.

11. The hose assembly according to claim 1, wherein the strength member comprises a plurality of individual wires, and wherein the strength member is attached to a termination block of the first termination assembly by clamping the individual wires between a clamping member an interior surface of the termination block.

12. The hose assembly according to claim 1, wherein the first and/or second termination assembly comprises a connection section by means of which it is connectable to a respective fitting of a subsea device, to a rear end of a subsea connector, or to a respective bulkhead fitting.

13. The hose assembly according to claim 1, wherein the hose assembly is a pressure balanced oil filled hose assembly, wherein the hose has a radial compliance that allows pressure compensation between a medium filling the hose and an ambient medium.

14. The hose assembly according to claim 1, wherein the strength member and/or a protection tube are disposed loosely in the interior space of the hose.

15. A subsea cable harness comprising: a hose assembly according to claim 1, and at least one subsea connector and/or fiber management unit mounted to the first or second termination assembly.

16. The hose assembly according to claim 1, wherein the strength member is configured to limit the expansion of the hose in a longitudinal direction upon application of a tensile stress to a value that is smaller than 0.5% of the hose's length in the longitudinal direction.

17. The hose assembly according to claim 1, wherein the strength member is configured to limit the expansion of the hose in a longitudinal direction upon application of a tensile stress to a value that is smaller than 0.2% of the hose's length in the longitudinal direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The foregoing and other features and advantages of the invention will become further apparent from the following detailed description read in conjunction with the accompanying drawings. In the drawings, like reference numerals refer to like elements.

[0043] FIG. 1 is a schematic drawing showing a sectional side view of a hose assembly according to an embodiment.

[0044] FIG. 2 is a schematic drawing showing the encircled region of FIG. 1 in more detail.

[0045] FIG. 3 is a schematic drawing showing a sectional side view of a first end of the hose assembly of FIG. 1.

[0046] FIG. 4 is a schematic drawing showing a subsea cable harness according to an embodiment.

DETAILED DESCRIPTION

[0047] In the following, embodiments illustrated in the accompanying drawings are described in more detail. It should be clear that the following description is only illustrative and non-restrictive. The drawings are only schematic representations, and elements in the drawings are not necessarily to scale with each other.

[0048] FIG. 1 illustrates a hose assembly 100 for underwater use, it may also be termed subsea hose assembly. A hose in this context is flexible tube into which other components may be placed. The hose assembly includes a hose 30 having an interior space 33 in which a signal carrier 10 is disposed. Furthermore, it includes a strength member 20, such as a reinforcing rod or bar, disposed in the interior space 33 of hose 30. In the embodiment of FIG. 1, a protection tube 15 is provided around the signal carrier 10. The hose 30 is filled with a substantially incompressible medium, in particular a dielectric liquid, and the strength member 20 is free to move within the interior space 33. Similarly, the signal carrier 10 and the protection tube 15 are free to move inside the hose 30.

[0049] Due to such movements, the strength member 20 may apply a force to the signal carrier 10, which may in turn suffer damage. Such damage to signal carrier 10 is prevented by the protection tube 15 which protects the signal carrier 10 against such forces.

[0050] The situation is illustrated in more detail in FIG. 2 which shows that the protection tube 15 including the signal carrier 10 and the strength member 20 are disposed within the interior space 33 of hose 30. Hose 30 may be a conventional hose used in subsea cables, such as the Anguila hose conduit provided by Siemens. For example, such hose may have an outer jacket, an armor made of polyester, strain elements made of Aramid, and inner liner. The Aramid strain elements may for example be disposed between the outer jacket and the inner liner. Such hose may provide sufficient strength so it can withstand the handling by an ROV. On the other hand, such hose provides compliance in radial direction in order to allow pressure compensation of the interior space 33 to the surrounding environment. Particular, the hose 30 will accommodate volume changes of the liquid filling the hose 30 caused by pressure and/or temperature changes.

[0051] Different types of tubing are suitable to be used as protection tube 15. As an example, protection tube 15 may be a nylon tube, a polypropylene tube or a tube made of another suitable material that is capable of protecting the signal carrier 10 against the above mentioned forces.

[0052] Now turning back to FIG. 1, the hose assembly 100 comprises at a first end a first termination assembly 50 and at a second end a second termination assembly 60. The termination assemblies 50, 60 may be configured similarly. The subsequent description focuses on the first termination assembly 50, but the explanations equally apply to the second termination assembly 60.

[0053] The termination assembly 50 comprises a termination block 51 in which the strength member 20 is terminated. The termination block 51 further comprises a through hole through which signal carrier 10 is led. Furthermore, if a protection tube 15 is provided, the protection tube 15 can also be led out of the hose through the through hole in the termination block 51, as illustrated in FIG. 1.

[0054] The first termination assembly 50 furthermore comprises a hose fitting 52. The first end 31 of the hose 30 is terminated and sealed by the hose fitting 52. The hose fitting 52 may be attached to the end 31 of hose 30 by swaging, it may be a swaged fitting. In particular, the hose fitting 52 may comprise an outer sleeve and an inner sleeve that are pressed together (e.g. by a swaging tool) to clamp the end 31 of hose 30 there between. As can be seen in FIG. 1, the sleeves are provided with protrusions to retain the hose 30 firmly in the hose fitting 52.

[0055] The hose fitting 52 has a through hole through which the strength member 20 extends towards the terminating block 51. Further, the hose fitting 52 has a through hole through which the signal carrier 10 and the protection hose 15 extend to the terminating block 51.

[0056] This is shown in more detail in FIG. 3. In the example of FIG. 3, the first termination assembly 50 is mounted to a subsea device 220, such as a fiber management unit. The termination block 51 is inserted into an opening in the subsea device 220, it can be slid into such opening. The hose fitting 52 comprises a connection section in form of nut 54 by means of which the hose fitting 52 is mounted in the opening of the subsea device 220. Two seals 58 on the hose fitting 52 provide sealing and a double barrier against ingress of seawater.

[0057] The strength member 20 is provided at each end with an end fitting 21, 22. The end fitting 21 is retained in the termination block 51. The end fitting 21 can be provided in different forms. In the example of FIG. 3, the end fitting 21 is provided by inserting the strength member 20 through a through hole 55 in the termination block 51. The through hole 55 has a tapered shape. Individual wires of the strength member 20 are then splayed out and a collet is inserted into the through hole 55. The collet may have a shape that corresponds to the tapered shape of the through hole 55 and may clamp the individual wires in the through hole. In FIG. 3, the collet is indicated by reference numeral 23, but it is not visible since it is covered by the respective wires. Furthermore, a former or crown can be provided above the collet. The first end fitting 21 is held in place by a set screw or grub screw 53. By tightening the grub screw 53, a compressive force can be applied and an effective clamping of the wires of the strength member 20 in the through hole 55 can be achieved.

[0058] In other embodiments, the first end termination 21 can be configured differently. As an example, a fitting having a larger diameter than the strength member 20 may be welded to the end of the strength member 20 and may be retained in a respective through hole which may be tapered or not.

[0059] The second end fitting 22 on the other end of the strength member 20 may be configured similarly.

[0060] As can be seen in detail in FIG. 3, the signal carrier 10, as well as the protection tube 15 are led through the hose fitting 52 and the termination block 51 into an interior space of the subsea device 220. The termination assembly 50 may be compatible with a range of different subsea devices and connectors, and it may as well be fitted into a rear section of a subsea connector, in particular a wet-mateable connector. In such configurations, a penetrator may furthermore be provided for the data carrier 10 for leading the data carrier 10 into the connector, so that the volume of the cable and the inner volume of the connector can be kept separate.

[0061] In an embodiment, the strength member 20 is a steel cable. Such steel cable may be composed of a plurality of individual steel wires. Such steel cable may have a thickness of between about 10 mm and about 1 mm, it may for example be 3 mm thick. To such steel cable, substantial tensile forces can be applied without significant stretching of the steel cable. The strength member 20 may in particular be configured to stretch less than 1%, advantageously less than 0.5%, more advantageously less than 0.2% of its length when a tensile force is applied, for example when the hose assembly is accidentally caught by an ROV or the like.

[0062] Turning back to FIG. 1, the hose 30, the signal carrier 10 and the strength member 20 are now configured such that any tensile stress applied to the hose assembly 100 is substantially transferred to the strength member 20 and absorbed by the strength member 20. Accordingly, if for example during installation, a pulling force is applied to one end of the hose assembly 100, e.g. by means of an ROV, such pulling force is applied to the strength member 20, so that the hose does not stretch and the signal carrier 10 does not experience tensile stress. It should be clear that the signal carrier 10 is generally affixed at some place in the subsea device or connector to which the hose assembly 100 is mounted, so that any expansion of the hose assembly 100 in the longitudinal direction would lead to a tensile stress being applied to the signal carrier 10. Accordingly, since in the embodiment of FIG. 1, such expansion is reduced significantly by the strength member 20, it is not necessary to provide a complex fiber management system that is capable of counteracting such expansion/contraction of the hose assembly.

[0063] As an example, the length of the strength member 20 may be slightly reduced so that it slightly compresses the hose 30 when mounted in the hose assembly 100. In other words, the strength member 20 may be pretensioned slightly. When both ends of the hose assembly 100 are pulled apart, the force is then applied almost completely to the strength member 20, while the hose 30 and the signal carrier 10 still have a certain degree of slack.

[0064] Other examples in which tensile stress may be applied to the hose assembly 100 is when a part of an ROV is accidentally caught by the hose 30, thus applying significant tensile forces to the hose assembly 30. Another example is contraction and expansion experienced by the hose 30 due to volume changes of the medium filling the interior space 33. As an example, when the medium expands, the hose 30 may experience contraction, and when the liquid cools, it may experience expansion. By providing a respective pre-tensioning of the strength member 20, such compression and expansion does not result in a tensile stress being applied to the signal carrier 10.

[0065] The signal carrier 10 may include at least one optical fiber. Preferably, the signal carrier 10 is a fiber ribbon. In other embodiments, the signal carrier 10 may additionally or alternatively include one or more electrical conductors for data transmission. In such configurations, the protection tube 15 may not be needed. In another embodiment, only one or more optical fibers, in particular a fiber ribbon, are provided as signal carrier 10.

[0066] FIG. 4 is a schematic drawing showing a subsea cable harness 200 according to an embodiment. The subsea cable harness 200 includes a hose assembly 100 that can have any of the above described configurations. The respective first and second termination assemblies 50, 60 are covered by respective boots 35. Boots 35 can be rubber boots or can be made of another plastic or polymer material. In the example of FIG. 4, the first termination assembly 50 is mounted to a rear portion of a subsea wet-mateable connector 250. The second termination assembly 60 is mounted to a subsea device in form of a fiber termination unit 230. The fiber termination unit 230 may for example comprise splices of the optical fibers of a fiber ribbon constituting the signal carrier 10. Accordingly, when a ROV applies a pulling force to the subsea connector 250 that leads to a tensile force in the hose assembly 100, the strength member 20 bears the load that is applied in the longitudinal direction of the hose 30. Tensile stress in the signal carrier 10 can thus be avoided.

[0067] Several advantages may be achieved with embodiments of the present invention. Provision of the strength member 20 is possible as a retrofit for existing subsea cables, or as part of the construction process using conventional hose and conventional signal carriers. Since the strength member 20 is provided within the hose 30, the external shape or appearance of the hose assembly 100 is not changed. Also, no additional external snag points at which for example a part of subsea equipment or an ROV component may be caught are added to the hose assembly 100. Also, since the strength member 20 is provided relatively close to the central axis of the hose 30, the load distribution may be improved compared to configurations in which an external strength member is provided that is located further away from the central axis. By providing the above outlined configuration of the strength member termination internal to the hose assembly, the strength member 20 may be integrated in current assembly procedures for hose assemblies without any significant modification or requalification, thus leading to a cost efficient solution. Also, and as mentioned above, no additional management system for the signal carrier 10 that counteracts a possible expansion and contraction of the hose 30 is required, whereby significant costs may be avoided. Also, the overall space required by the strength member 20 and its terminations is relatively small, so that a compact solution can be achieved, which from an outside view, is substantially no different from a conventional subsea cable employing an oil filled hose.

[0068] While specific embodiments are disclosed herein, various changes and modifications can be made without departing from the scope of the invention. The embodiments described herein are to be considered in all respects as illustrative at non-restrictive, and any changes coming within the meaning and a equivalency range of the appended claims are intended to be embraced therein.