AU2010201284B2 - Umbilical - Google Patents

Abstract

Abstract An umbilical comprising a side-emitting optical fibre or optical fibre-bundle for providing a distributed source of light along part or the whole of the length of the umbilical. Figure 1 I Z~ 7r .vf~e Z3, 1 3o 34 32 3 23A ko(Lr kroac6e Fx,

Description

AUSTRALIA FB RICE & CO Patent and Trade Mark Attorneys Patents Act 1990 UNIVERSITY COURT OF THE UNIVERSITY OF ST ANDREWS COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Umbilical The following statement is a full description of this invention including the best method of performing it known to us:- 1A Umbilical Field of the Invention This invention is concerned with the illumination of umbilicals, as employed in subsea 5 surface-air diving and subsea saturation diving, for the purpose of improved diver safety and efficiency of working. Background of the Invention In commercial subsea diving, supply of air to the diver from the surface is the preferred 10 method (as compared to the use of bottled air carried by the diver) since such a supply scheme places less stringent limitations on diver operating time underwater. Surface supplied air requires the diver to be linked to the surface through an umbilical for the supply of the air along with other services. 15 In commercial surface air diving umbilical lengths of 75m with depths down to 50m combined with an underwater operating radius of up to 25m typically need to be covered. Alternatively, through the use of saturation diving techniques depths down to 300m can be reached through the use of a diving bell. In this case an umbilical is required to connect the diver to the bell for the supply of air, with a requirement for the 20 diver being able to operate over a radius of up to 75m from the bell. In addition umbilicals may be required to connect remote operating vehicles (ROV) or their derivatives to a bell or other installations. Subsea commercial surface-air diving is globally important in the contexts of off-shore, 25 submerged tidal and ocean power generation installations, wind farms, harbour clearance, pipeline inspection, and wreck inspection/salvage. In addition saturation diving techniques are required in connection with the inspection and maintenance of oil platforms, and submerged well heads, at depths where surface air diving cannot reach. One of the dangers faced by divers in these environments is entanglement or fouling of 30 their umbilicals, which can significantly compromise diver safety and security. Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general 2 knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application. Throughout this specification the word "comprise", or variations such as "comprises" or 5 "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Summary of the Invention 10 According to one aspect of the present invention, there is provided an umbilical that comprises at least one side emitting optical fibre that extends along the length of the umbilical and at least one of a tube or hose provided for supplying gas or fluid. An illumination source is provided at either one or both ends of the at least one fibre. 15 By using a side emitting light fibre rope, the umbilical can be illuminated along its length, thereby alleviating some of the risks faced by divers. Such an umbilical has numerous advantages. For example, it can provide a guide-path to the surface and provides general illumination of the sub sea environment within which the diver or divers are working. This improves the working conditions, and thereby increases 20 efficiency of working. This is particularly important in situations where working time is limited by external constraints, as in the case of sub sea working. An illuminated umbilical also provides individual divers engaged with others on common tasks with an improved overall visual sense of the communal working environment. 25 The light rope umbilical of the present invention provides a distributed illumination source that is: capable of being installed as one element/strand of the overall umbilical; service-free within the usual lifetime of the umbilical; capable of being pre-installed as part of the standard manufacturing process for umbilicals, and activated if and when required without further modification of the umbilical; capable of withstanding the 30 rigours of the sub sea environment, particularly with regard to the impact of salt water; physically robust, thereby not suffering damage or failure as a consequence of being incorporated within the bundle of other connections associated with the umbilical; capable of being illuminated without requiring a distributed electrical or other supply along the length of the source for this purpose (i.e. it is a passive source along the 35 length of the umbilical); and capable of withstanding local failure/damage at points along its length without undergoing universal failure.

2A At least one illuminating source may be coupled to the optical fibre or optical fibre bundle. The illuminating source may be a light emitting diode (LED). The illuminating source may be at least one of: a laser; a diode laser; a diode-laser-pumped solid-state 5 laser. The umbilical may include a converter for converting the frequency of light from the source.

3 The light may be modulated to carry a message or information. The light modulation may be visible directly by eye, for example as in the case of a general warning message. Additionally or alternatively, an optical receiver may be provided for decoding the modulated message for presentation to a user. 5 Means may be provided for presenting the message to the user visually and/or orally. The umbilical may include at least one of a tube or hose; a cable for supplying power; a communications link. The at least one tube or hose may be provided for supplying gas, 10 for example air, or fluid, for example water. The optical fibre or optical fibre bundle may be wound round or intertwined with one or all of the tube or hose, the cable and the communications link. The illuminating source may be contained within a housing. The housing may have a 15 window that is transparent to light from the source. A coupling element may be provided for pressing the end of the fibre or fibre bundle against the window to provide a butt coupled optical connection. The housing may be waterproof. The housing may be pressurised. 20 A controller may be provided for controlling an output of the illuminating source. The controller may be adapted to cause flashing and/or a change in colour of the light emitted. The umbilical may be adapted for use as a diver umbilical. The umbilical may be 25 adapted for use between a surface and a subsea location and/or between a diving bell and an individual diver and/or between two or more locations subsea or surface to sea. The umbilical may be adapted to be connected to an underwater remote operating vehicle. 30 Brief Description of the Drawings Various aspects of the invention will now be described by way of example only and with reference to the accompanying drawings, of which: Figure 1 is a schematic representation of a light rope umbilical system; 35 Figure 2 is a view of a fibre-bundle as incorporated within the umbilical; 4 Figure 3 is a side view of an individual fibre of a light rope for use in the system of Figure 1; Figure 4 is a view of a fibre bundle showing helical pitch.; Figure 5 is an end view of bundle showing arrangement of individual fibres and 5 sleeving; Figure 6 shows the illuminator at the diver end for a fibre-bundle umbilical illuminated from both ends, and Figure 7 shows the umbilical in use in various operational environments. 10 Detailed Description of the Drawings Figures 1 and 2 show an umbilical in accordance with the invention. This has various conventional umbilical parts 23 that are wound together, such as a gas hose and a power line, as best seen in Figure 2. In addition, the umbilical of the invention includes a fibre-bundle 2 that has multiple side-emitting optical fibres. The side-emitting optical 15 fibres provide a distributed source of light that allows the umbilical to be lit along its length, thereby providing a guide-path as well as general illumination of the sub sea environment within which the diver or divers are working. For the purpose of illuminating the fibre bundle 2 a light emitting diode (LED) 4 is 20 provided powered by a driver 5. The LED 4 is enclosed within a compact watertight enclosure or light-box 6 which is located adjacent to an umbilical interconnect-interface 10. Radiation from the LED passes through an optical coupling arrangement 12 which transforms the spatial characteristics of the primary radiation from the LED to optimize its coupling into the fibre-bundle 2. The radiation then passes through a window 14 25 which is mounted on a water-tight seal 16 on the side of the watertight compartment 6, before entering the fibre-bundle 2. The prepared ends of the fibres making up the bundle are held in compression by element 18 so as to be in contact with and hence butt-coupled to the outer surface of the window. The optical arrangement described is such that this location of the fibre-end also optimizes the coupling of the radiation into 30 the fibre. Whilst any LED may be used, in a preferred example, the LED generates light in the green spectral region. Typically for an electrical input power to the LED of 12W, the optical output power from the LED in the green spectral region is of the order of 400 35 mW, and the coupling efficiency for this radiation into the fibre is of the order of 23-28% 5 The fibre bundle may be made up of any number of fibres. In a preferred example fourteen individual plastic fibres 20 are used with a core diameter of 0.74mm and refractive index of 1.49, and with an outer cladding of wall thickness 0.06mm and 5 refractive index 1.40, see Figure 3. As a specific example these fibres would conform to Eska CK30 fibre. The fibres are wound in a tight helical bundle 22 with a pitch of 10 cm, see Figure 4. The packing of the fibres as appears at each end of the bundle is of the form of 4 central fibres surrounded by 10 other fibres 20, all encased within an outer sheath 26 that is transparent to the light that is to be used, see Figure 5. The 10 plastic sheaf 26 has a nominal wall thickness of 0.85mm, the walls of the sheaf being transparent to the green radiation. Typically the fibre bundle 2 would be of length 100m, compatible with a standard umbilical, 23. The fibre-bundle geometry of Figure 5 typically experiences a loss of the order of 15 5%/m due to radiation escaping through the side walls as required, this being determined both by the tightness of winding and the compression of the bundle by the outer sleeve. Both these aspects are controllable for the purposes of optimization during the manufacturing process. For the specifications given above satisfactory illumination and brightness of emission is attained for fibre lengths up to 100m. The 20 watertight compartment 6 also contains a back-up battery 40 (3 hours of steady state lighting or 6 hours on flash) with a built in charger circuit 41. This circuit 41 contains the flash interface which is controlled from the surface by the dive supervisor. This will also allow remote operation in the event on no mains. The system in normal operation requires 12W @18V DC. 25 In some circumstances, it may be desirable to allow the injection of light from both ends of the fibre. Another arrangement is where the fibre is illuminated from both ends, namely from the surface end of the fibre as described above and also from the underwater end as attached to the diver. For the latter purpose Figure 6 shows a 30 compact watertight pressurised light-box 28 designed to operate at depth of typical dimensions 100mmx50mm diameter which is attached at the diver end to the fibre and contains a rechargable battery 30, LED 32, associated driver circuit 34, optical coupling arrangement 36, and output coupling window 38 with facility for butt-coupling the fibre ends as previously. 35 6 Overall characteristics for the underwater source for use in the arrangement of Figure 6 regarding optical power into fibre, etc. are similar to the surface based illuminator. Under normal operating conditions the system is powered by the diver's electrical supply emanating from the surface and provided by the power cable of the umbilical, 5 but with a battery back-up of one hour. This arrangement significantly increases illumination levels in the vicinity of the diver(s), and provides back-up through built-in redundancy in the event of fibre damage or light source failure. It can also significantly increase umbilical operational length. 10 The light injected into the fibre bundle may be modulated so as to carry a message or information. The modulation of light may be such that it can be seen directly by eye, for example in the case of a general warning message. Alternatively or additionally, an optical receiver capable of decoding the modulated message may be provided for subsequent oral, visual or other mode of presentation to divers or other relevant 15 parties. A controller (not shown) may be provided at one or both ends of the umbilical to cause the light emitted from the fibres to be altered. For example, the light could be caused to flash on and off. This could be used by divers in emergency situations to provide a 20 general warning, for example, highlighting a change in operational conditions or a specific diver in difficulty, thereby making colleagues immediately aware of a changed state. A lit and flashing umbilical could speed up rescue operations in identifying the diver at risk. 25 Figure 7 shows various different operational enviroments in which the umbilical of the invention could be used. These include between the surface and a subsea location (surface-air diving application), Figure 7(a) or between a diving bell and individual divers (saturation diving), Figure 7(b). It may also be used between two or more subsea locations for example in connection with remote operating vehicles (ROVs), as 30 shown in Figure 7(c) and Figure 7(d). The present invention provides a safe, low-power light-source that is continuous, flexible and distributed along the full length of the umbilical. The source can be used in any underwater environment for example subsea and any inland waters including 35 lakes, rivers, lochs, harbours, docks, canals and all other types of waterways. The 7 source requires no electrical power within the structure of the umbilical itself and can provide high intensity light at the peak eye response, as well as light of other colours if required. It provides a clear return path back to safety resulting from the distributed and continuous nature of the source along the length of the umbilical. It provides visual 5 information between divers as to their relative locations in the subsea environment, as well as general illumination of the underwater working environment thereby increasing the visual acuity of operatives so improving both their safety and their efficiency of working. 10 A skilled person will appreciate that variations of the disclosed arrangements are possible without departing from the invention. For example, although the invention is described with reference to a bundle of fibres, a single fibre or a light pipe may be used. Equally, the illuminator may be any suitable device, such as a filament / halogen / thermal resistance illuminator, or a laser, for example a diode laser, such as a diode 15 laser-pumped solid-state laser. The wavelength of the radiation generated by the laser may be shifted in frequency by some optically nonlinear technique so as to be suited to the purpose. Whilst green is a preferred colour any spectral colour may be used. Accordingly the above description of the specific embodiment is made by way of example only and not for the purposes of limitation. It will be clear to the skilled person 20 that minor modifications may be made without significant changes to the operation described.

Claims (23)

1. An umbilical comprising a side-emitting optical fibre or optical fibre-bundle for 5 providing a distributed source of light along part or the whole of the length of the umbilical, and at least one of a tube or hose for supplying a gas or fluid.

2. An umbilical as claimed in claim 1 comprising at least one illuminating source coupled to the optical fibre or optical fibre-bundle. 10

3. An umbilical as claimed in claim 2 where the illuminating source is a light emitting diode (LED).

4. An umbilical as claimed in claim 2 wherein the illuminating source is at least one 15 of: a laser; a diode laser; a diode-laser-pumped solid-state laser.

5. An umbilical as claimed in claim 3 or claim 4 comprising a converter for converting the frequency of light from the source. 20

6. An umbilical as claimed in any one of claims 2 to 5 wherein the light is modulated to carry a message or information.

7. An umbilical as claimed in claim 6 wherein the light modulation is visible directly by eye. 25

8. An umbilical as claimed in claim 6 or claim 7 wherein an optical receiver is provided for decoding the modulated message for presentation to a user.

9. An umbilical as claimed in claim 8 comprising means for presenting the message 30 to the user visually and/or orally.

10. An umbilical as claimed in any one of claims 2 to 9 wherein the illuminating source is contained within a housing. 35 9

11. An umbilical as claimed in claim 10 wherein the housing has a window that is transparent to light from the source.

12. An umbilical as claimed in claim 11 wherein a coupling element is provided for 5 pressing the end of the fibre or fibre bundle against the window to provide a butt coupled optical connection.

13. An umbilical as claimed in any one of claims 10 to 12 wherein the housing is waterproof. 10

14. An umbilical as claimed in any one of claims 10 to 13 wherein the housing is pressurised.

15. An umbilical as claimed in any one of claims 2 to 14 wherein a controller is 15 provided for controlling an output of the illuminating source.

16. An umbilical as claimed in claim 15 wherein the controller is adapted to cause flashing and/or a change in colour of the light emitted. 20

17. An umbilical as claimed in any one of the preceding claims comprising a cable for supplying power and/or a communications link.

18. An umbilical as claimed in claim 17 wherein the optical fibre or optical fibre bundle is wound round one or all of the tube or hose, the cable and the 25 communications link.

19. An umbilical as claimed in any one of the preceding claims adapted for use as a diver umbilical. 30

20. An umbilical as claimed in claim 19 wherein the umbilical is adapted for use between a surface and a subsea location.

21. An umbilical as claimed in claim 19 wherein the umbilical is adapted for use between a diving bell and an individual diver. 35 10

22. An umbilical as claimed in claim 19 wherein the umbilical is adapted for use between two or more locations subsea or surface to sea.

23. An umbilical as claimed in claim 19 wherein the umbilical is adapted to be 5 connected to an underwater remote operating vehicle.