AU2017200477B2

AU2017200477B2 - Environmental protection

Info

Publication number: AU2017200477B2
Application number: AU2017200477A
Authority: AU
Inventors: Neil Douglas; Matthew Harris; Steve Simpson
Original assignee: Viper Innovations Ltd
Current assignee: Viper Innovations Ltd
Priority date: 2016-01-26
Filing date: 2017-01-24
Publication date: 2018-05-24
Anticipated expiration: 2037-01-24
Also published as: GB2593656B; GB2546893B; GB201700834D0; GB2593656A; AU2017200477A1; AU2018202244B2; AU2018202244A1; GB2546893A; GB202110079D0; GB201601385D0

Abstract

ENVIRONMENTAL PROTECTION 5 A distribution unit 10 is described comprising a housing 12 having a plurality of connectors 16, 18 to permit the connection of a plurality of lines or cables thereto such that, in use, the distribution unit 10 can be used in the distribution of inputs to a plurality of pieces of subsea equipment, the housing 12 including at least one socket 20 in which an active device 22 can be fitted to allow tests to be conducted and/or to permit 10 enhanced control, and a seal arrangement 36 whereby a seal can be formed between the active device 22 and the socket 20, the relative dimensions of the socket 20 and the active device 22 being such that only a small volume exists therebetween. Also described is an arrangement 50, 60 comprising a housing 52, 62, equipment located within the housing 52, 62, and a barrier fluid 54, 64, 66 located within the housing 52, 15 62 providing environmental protection to the equipment located within the housing 52, ".. .Mg I'&rr * ~ ~ s ~ Joel EM somom RR* gf\X,1' lam"'~ * * hook 'J*. ME'ty .. . . .. . . . . .. . . . . . .. . . .. . . . . .. . . . . .. .. . . .. . . . .. .. . . .. . .. . 22. . . . . .. . . . . . .

Description

The invention will further be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic view of a distribution unit in accordance with an embodiment of the invention;

Figures 2 and 2a are diagrammatic views illustrating part of the distribution unit of

Figure 1, partly in section, with parts removed;

Figure 3 is a view illustrating an active device of the distribution unit of Figure 1;

Figures 4 and 5 are illustrations of a distribution unit arrangement in accordance with another embodiment of the invention; and

Figures 6 and 7 are illustrations of a distribution unit arrangement in accordance with another embodiment of the invention.

Referring firstly to Figures 1 to 3, a distribution unit 10 in accordance with an embodiment of the invention is illustrated. The distribution unit 10 comprises a housing 12 supported upon legs 14 intended for installation in a subsea location. The housing 12 includes a series of connectors including an input connector 16 whereby an umbilical or other cable can be connected to circuits located within the housing 12 and a series of output connectors 18 whereby cables can be connected to the distribution unit 10 to connect the distribution unit 10 to other pieces of subsea equipment. As is

2017200477 27 Mar 2018 well known, the circuits within the distribution unit 10 are operable to allow power and/or control signals supplied via the umbilical or the like to be distributed to the various pieces of equipment connected to the distribution unit 10. As this function is well known, it is not described herein in further detail.

As shown, the housing 12 is formed with a series of sockets 20, each socket 20 being adapted to receive an active device in the form of a test device 22. As shown in Figures 2 and 2a, each socket 20 takes the form of a hollow, generally cylindrical housing 24 or stepped inner diameter. The housings 24 are mounted to the top of the housing 12 of the distribution unit 10, and within a lower part of each housing 24 is located an electrical connector stub 26, the stub 26 being generally coaxial with the housing 24. The electrical connector stub 26 is electrically connected to the circuits of the distribution unit 10. A barrier fluid 40 is located within the socket 20, the barrier fluid 40 covering the connector stub 26 when the test device 22 is not fitted to the socket 20, thus protecting the connector stub 26 against the build-up of marine growth.

The manner in which tests are undertaken using the test device 22 will be understood by a person skilled in the art, and so is not described herein in further detail.

Whilst this embodiment makes use of active devices in the form of test devices 22, it will be appreciated that the invention is also applicable to arrangements in which the active devices perform other functions, for example enhanced control functions, communications functions or the like.

The test device 22 comprises a generally cylindrical body 28 of dimensions and shape such that it can be at least partially received within the housing 24. An upper end of the body 28 includes a handle 30 to aid manipulation thereof, and a key 32 projects from the outer surface of the body 28 for receipt within a corresponding key way formed in the socket 20 to ensure that the test device 22 can only be introduced into the socket 20 in a single angular orientation, thereby ensuring correct make up of electrical connections, in use.

Projecting from a lower part of the body 28 is a hollow connector part 34 adapted to fit over the connector stub 26 in such a manner as to make electrical contact therewith so as to electrically connect circuits within the test device 22 with circuits within the distribution unit 10.

2017200477 27 Mar 2018

A seal member 36 extends around the periphery of a part of the body 28, the seal member 36 cooperating, in use, with the inner surface of the socket 20 to restrict sea water ingress into the socket when the test device 22 is fitted thereto.

With the distribution unit 10 installed in a subsea location, and with umbilicals, cables or the like connected to the connectors 16, 18 as required, if it is desired to undertake tests on the various cables or the like or subsea located pieces of equipment, then test devices 22 may be fitted to the sockets 20. Depending upon the tests to be undertaken, it may be desired for the test device 22 to be fitted to a specific one of the sockets 20. When the test device 22 is fitted, it will be appreciated that the barrier fluid located within the socket 20 is displaced by the connector part 34, the barrier fluid 40 then substantially filling a volume defined between the test device 22 and the socket 20.

It will be appreciated that with the test device 22 fitted, tests may be undertaken on the distribution unit, and the cables and equipment connected thereto, to identify the nature and location of faults associated therewith. The nature of the tests may depend upon the functionality of the test device 22, and if desired, a number of interchangeable test devices may be provided to enable a range of tests to be undertaken.

With the test device 22 fitted, it will be appreciated that the barrier fluid 40 provides protection to the connectors associated with the test device 22 and socket 20, and the presence of the seal member 36 restricts sea water ingress into the socket 20 and the escape of barrier fluid therefrom. The barrier fluid 40 is preferably electrically inert, providing an additional electrical barrier for the connectors. In addition, by restricting sea water ingress, the risk of marine growth occurring within the socket 20 is reduced.

When no tests are required to be undertaken, the test device 22 may be removed. If desired, it may be replaced by a similarly shaped passive device 22a. The presence of the seal member 36 and barrier fluid 40 will again serve to protect the integrity of the connector stub 34.

Although the test devices 22 are removable/replaceable, and so lend themselves to temporary installation or reconfiguration, they may, if desired, be installed on a long term basis, and may be retrofitted to previously installed distribution units, if desired.

2017200477 27 Mar 2018

Whilst in the arrangement described hereinbefore a barrier fluid is provided in the socket, in some arrangements this fluid may be omitted, the presence of the seal member restricting sea water ingress into the space between the test device and the socket, in combination with the volume of the space between the test device and the socket being small, being sufficient to prevent marine growth.

Turning to Figures 4 and 5, a distribution unit arrangement 50 is illustrated, the arrangement comprising a distribution unit 10 of the general form described hereinbefore. In the arrangement of Figures 4 and 5, the positions of the connectors 16, 18 have been modified, but the invention is not restricted in this regard and could be employed using a distribution unit of the type shown in Figures 1 to 3. The distribution unit arrangement 50 further comprises a housing in the form of a trough 52 within which the distribution unit 10 is located. The trough 52 is of closed bottomed form, and a barrier fluid 54 of density greater than sea water is located therein. The barrier fluid 54, like that used in the socket 20, is of electrically inert, non-conductive form. It is preferably non-biodegradable so as to be suitable for use over an extended period of time, and is preferably environmentally friendly, thereby minimising any negative environmental impacts that may occur in the event that the material mixes with sea water and/or escapes from the trough 52. The trough 52 and depth of the barrier fluid 54 located therein are preferably such that the connectors 16, 18, and components physically connected thereto, are completely immersed in the barrier fluid 54. The connections to the distribution unit 10 are thus separated from the sea water, and the risk of damage arising through contact with sea water, for example, water ingress to electrical components, the build-up of marine growth, or the like, is reduced. Electrical connections to the distribution unit 10 may be made and/or broken within the barrier fluid 54.

As illustrated, the trough 52 is conveniently provided with a lid 56 that may be removed to gain access to the distribution unit 10, to allow removal or connection of components thereto. The design of the lid 56 is preferably such that the test devices 22 may be removed without the need to remove the lid 56. However, the invention is not restricted in this regard. The primary purpose of the lid 56 is to avoid water currents from washing away the barrier fluid 54, and it may also serve to restrict access to the connectors 16, 18. It will be appreciated that in some arrangements, the lid 56 may be omitted, if desired.

2017200477 27 Mar 2018

It is envisaged that deployment of the arrangement shown in Figures 4 and 5 will involve positioning the distribution unit 10 and trough 52 in the desired location, introducing the barrier fluid 54 into the trough 52 and then establishing the desired electrical connections to the distribution unit 10, the connections being made within the barrier fluid 54. After establishing the electrical connections, the lid 56 may be fitted, and thereafter the test devices 22 (and/or passive devices 22a) fitted in position. Alternatively, the test devices 22 and/or passive devices 22a could be fitted in position prior to deployment of the distribution unit 10. To recover the arrangement to the surface, after removal of the lid 56 and breaking of the electrical connections, the barrier fluid 54 is drained into a suitable receptacle prior to lifting the distribution unit 10 and trough 52 to the surface.

Whilst the description hereinbefore is of a distribution unit arrangement 50 using a distribution unit 10 of substantially the form described with reference to Figures 1 to 3, it will be appreciated that the invention is also applicable to arrangements in which other forms of distribution unit are used, for example distribution units 10 that do not have sockets 20 for fitting test devices 22 thereto.

Figures 6 and 7 illustrate an alternative distribution unit arrangement 60. In the arrangement 60, a housing 62 is provided over the distribution unit 10, the housing 62 being of open bottomed form, and closed at its top. For convenience, the housing 62 is hingedly connected to the distribution unit 10 (and is shown in its open condition in Figure 6), but this need not always be the case. The arrangement is adapted such that, once the required electrical connections have been made to the distribution unit 10 and the required test devices 22 and/or passive devices 22a fitted thereto, the housing 62 is secured in position with at least the connectors 16, 18 of the distribution unit 10 located within the housing 62. Once so positioned, a barrier fluid 64 in the form of a gas, such as nitrogen gas, of density less than sea water is introduced into the housing 62, displacing the sea water therefrom to a level such that the connectors 16, 18 are not covered by the sea water, but rather are exposed to the barrier fluid 64.

The barrier fluid 64 should preferably be of a non-toxic material, and ideally should not be corrosive in the presence of water. As mentioned above, nitrogen gas may form a suitable material for the barrier fluid 64. It may be introduced into the housing 62 from, for example, a pressurised gas canister mounted upon the housing 62.

2017200477 27 Mar 2018

Preferably, prior to introducing the barrier fluid 64 into the housing 62, a quantity of a second barrier fluid 66 of density greater than the first barrier fluid 64 but lower than that of sea water is introduced into the housing 62. The second barrier fluid 66 will thus float upon the sea water within the housing 62. Upon the introduction of the first barrier fluid 64, the second barrier fluid 66 serves to separate the sea water from the first barrier fluid 64. This may be beneficial as, in the absence of the second barrier fluid, some sea water may evaporate into the first barrier fluid 64, and the combination of the sea water and the first barrier fluid 64 may, depending upon the materials used, be corrosive. By isolating the first barrier fluid 64 from the sea water using the second barrier fluid 66, the risk of corrosion arising in this manner is reduced. The second barrier fluid 66 should preferably be non-hydroscopic, should be a dielectric, should be environmentally friendly, non-toxic and non-biodegradable. It may comprise, for example, silicon oil.

Deployment of the arrangement may involve installing the distribution unit 10 and housing 62 in the desired location, moving the housing 62 to an open condition to allow access to the distribution unit 10 so that connections can be made thereto and test devices 22 and/or passive devices 22a installed thereon. Subsequently, the housing

62 is secured in position on the distribution unit 10. The second barrier fluid 66 is then released from a bladder 66a located within the housing 62, for example by way of an ROV operable valve or the like, so as to float upon the surface of the sea water within the housing 62, after which the first barrier fluid 64 is introduced into the housing 62, for example via a bleed/fill valve 68 displacing the seawater from the upper part of the housing 62. Conveniently, a window or float indicator or the like is provided to allow an operator to know when the desired quantity of sea water has been displaced, the connectors 16, 18 being located within the first barrier fluid 64 at that point.

Rather than supplying the first barrier fluid 64 from a cylinder or the like, it could be generated by causing a gas generating chemical reaction to occur beneath the housing 62. Similarly, rather than supplying the second barrier fluid from a bladder 66a located within the housing 62, other techniques are possible.

To recover the arrangement, the first barrier fluid 64 is vented from the housing 62 via the valve 68 to the surrounding sea water. The second barrier fluid 66 is then returned to the bladder 66a or another suitable receptacle. After venting or collection of the

2017200477 27 Mar 2018 barrier fluids, the housing 62 can be released and moved to allow access to the distribution unit 10. The connections to the distribution unit 10 can be broken, and the arrangement then lifted to the surface.

By modifying the design of the housing 62, it is thought that both the barrier fluids 64, 66, or alternatively just the second barrier fluid 66, may be retained within the housing 62 both when the housing 62 is in its in use position and when it is moved to the open position in which access to the distribution unit 10 is permitted.

As with the arrangement shown in Figures 4 and 5, the arrangement of Figures 6 and 7 is advantageous in that corrosion of components of the distribution unit and associated connectors is reduced, the formation of marine growth is avoided, and the connectors are maintained in a clean condition. The barrier fluids serve to provide an additional electrical barrier, and cathodic protection demands are reduced.

Although the arrangement of Figures 6 and 7 uses a distribution unit 10 of the type described hereinbefore, it will be appreciated that the invention is not restricted in this regard, and distribution units that do not include removable test devices may also be used without departing from the scope of the invention.

In the description hereinbefore, for the most part the distribution unit is described as being used in the distribution of electrical power and/or signals. It will be appreciated, however, that the invention is not restricted to such arrangements, and may be employed in applications in which other connectors such as hydraulic or chemical conducting connectors are used, or in which optical fibres or the like are used. Indeed, the invention may be employed in providing protection for devices other than distribution units.

Whilst specific embodiments of the invention are described hereinbefore, it will be appreciated that a wide range of modifications and alterations are possible without departing from the scope of the invention as defined by the appended claims.

2017200477 27 Mar 2018

Claims

CLAIMS:

1. A distribution unit comprising a housing having a plurality of first connectors to permit the connection of second connectors associated with a plurality of lines or

5 cables or devices thereto such that, in use, the distribution unit can be used in the distribution of inputs to a plurality of pieces of subsea equipment, and a seal arrangement whereby a seal can be formed between at least one of the second connectors and a respective one of the first connectors, the relative dimensions of the first and second connectors being such that only a small volume exists therebetween, a

10 barrier fluid being located within the first connector and into which at least part of the second connector projects or extends when the first and second connectors are mated to one another, the barrier fluid being of greater density than sea water and the first connector being orientated such that the barrier fluid is retained therein where the second connector is not mated therewith.

2. A unit according to Claim 1, wherein at least one of the first connectors comprises a socket.

3. A unit according to Claim 2, wherein an active device can be fitted into the

20 socket to allow tests to be conducted and/or to permit enhanced control.

4. A unit according to Claim 3, wherein the active device is removably fitted to the socket.

25 5. A unit according to Claim 4, wherein, when the active device is not fitted to the socket, a passive device is fitted thereto.

6. A unit according to any one of the preceding claims, wherein the barrier fluid is electrically non-conductive.

7. A unit according to any one of the preceding claims, wherein the barrier fluid is selected to impede marine growth.

8. A unit according to any one of the preceding claims, wherein the barrier fluid is

35 selected to be of an environmentally friendly material.

2017200477 27 Mar 2018

9. A unit according to any one of the preceding claims, wherein the barrier fluid is selected to be non-biodegradable.

10. A unit according to any one of the preceding claims, wherein a second barrier

5 fluid is located within the housing.

11. A unit according to Claim 10, wherein the second connector is, in use, located within the second barrier fluid located within the housing.

10 12. A unit according to Claim 11, wherein the second connector, or at least one of the second connectors, is an electrical connector, a connector for a hose or a connector for an optical fibre.

13. A unit according to any one of Claims 10 to 12, wherein the second connector,

15 or at least one of the second connectors, comprises a stabplate.

14. A unit according to any of Claims 10 to 13, wherein the second barrier fluid is of greater density than sea water, and the housing is orientated such that the second barrier fluid is retained therein.

15. A unit according to Claim 14, wherein the housing takes the form of an open topped trough within which the second barrier fluid is located, and into which at least a part of the second connector extends.

25

16. A unit according to Claim 14 or Claim 15, wherein the housing includes a lid.

17. A unit according to any one of Claims 10 to 13, wherein the second barrier fluid is of density lower than sea water.

30

18. A unit according to Claim 17, wherein the second barrier fluid comprises a gas.

2017200477 26 Apr 2018

19. A unit according to Claim 17 or Claim 18, further comprising a third barrier fluid of density greater than the second barrier fluid but lower than sea water, the third barrier fluid serving to separate the second barrier fluid from the sea water.

5 20. A unit according to Claim 19, further comprising a bladder for containing the third barrier fluid when not deployed.

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