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Title:
A HOTSTAB DEVICE FOR USE UNDER WATER
Document Type and Number:
WIPO Patent Application WO/2007/086753
Kind Code:
A1
Abstract:
A hotstab device (1) for use with a submarine vehicle, where the hotstab (1) is a complementary fit to a submerged connection block (4) , and where the hotstab (1) comprises passages (6) for conveying pressurized fluid, and where a first transformer section (12) is arranged on the hotstab (1) and a second transformer section (24) , which in the operative position cooperates with the first transformer section (12) , is located at the connection block (4) , the transformer sections (12, 42) providing noncontact transmission of electrical energy.

Inventors:
HODNEFJELL LARS GUNNAR (NO)
JACOBSEN EIRIK KLOSTER (NO)
Application Number:
PCT/NO2007/000022
Publication Date:
August 02, 2007
Filing Date:
January 22, 2007
Export Citation:
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Assignee:
IFOKUS ENGINEERING AS (NO)
HODNEFJELL LARS GUNNAR (NO)
JACOBSEN EIRIK KLOSTER (NO)
International Classes:
H01F38/14; E21B33/035; H01R13/523
Foreign References:
GB2209361A1989-05-10
US6188327B12001-02-13
US5052941A1991-10-01
Attorney, Agent or Firm:
HÅMSØ PATENTBYRÅ ANS (Sandnes, NO)
Download PDF:
Claims:
C l a i m s

1. A hotstab device (1) for use under water, where the hotstab (1) is a complementary fit to a submerged connection block (4) , and where the hotstab (1) comprises passages (6) for conveying pressurized fluid, charac t er i z ed in that a first transformer section (12) is arranged on the hotstab (1) and a second transformer section (24) , which in the operative position cooperates with the first transformer section (12), is located at the connection block (4), the transformer sections (12, 24) providing noncontact transmission of electrical energy.

2. A device in accordance with Claim 1, charac ter i z ed in that the noncontact transmission of energy is inductive.

3. A device in accordance with Claim 1, charac t eri z ed in that the transformer sections (12, 24) are constructed so to allow them to be pushed into or against each other in a mechanical manner .

4. A device in accordance with Claim 1, charac t er i z ed i n that at least one of the first transformer section (12) or the second transformer section (24) is completely or partially mounted in a rubber-like material (36) .

5. A device in accordance with Claim 1, charac t er i z ed i n that at least one of

the first transformer section (12) or the second transformer section (24) is enclosed by the rubber- like material (36) .

6. A device in accordance with Claim 1, c h a r a c t e r i z e d i n that the rubber-like material (36) is constituted at least partly by an elastomer.

7. A device in accordance with Claim 1, c ha ra c t e r i z e d i n that the rubber-like material (36) is constituted at least partly by polyurethane .

8. A device in accordance with Claim 1, c h a r a c t e r i z e d i n that the rubber-like material (36) is constituted at least partly by natural rubber .

9. A device in accordance with Claim 1, c h a r a c t e r i z e d i n that the rubber-like material (36) is constituted at least partly by synthetic rubber.

Description:

A HOTSTAB DEVICE FOR USE UNDER WATER

This invention regards a hotstab device for use under water. More particularly, it regards a hotstab where the hotstab is a complementary fit to a submerged connection block, and where the hotstab comprises passages for conveying pressurized fluid. A first transformer section is arranged on the hotstab and a second transformer section, which in the operative position cooperates with the first transformer section, is located at the connection block, the transformer sections providing noncontact transmission of electrical energy.

In several environments where there is a risk of corrosion on or flashover between electrical contacts, there has long been a wish to use noncontact means of transferring electrical energy for both signals and electrical power, eg. for operation of equipment. In this context, the term noncontact transmission of energy refers to the transmission of energy between bodies without any mechanical contact. The following is based on the hotstab being located on an ROV. This example is used for illustrative purposes and will in no way limit the scope of the invention.

Only recently has equipment emerged which, has a satisfactory capacity for noncontact transmission of any significant amount of energy. Thus, Norwegian patent no. 320439 describes a method of transferring energy between two separated bodies by means of a resonant circuit between two transformer halves .

In the area of subsea technology it has long been common practice to transfer hydraulic energy from e.g. a submarine vehicle, often called an ROV (Remote Operated Vehicle) , by means of a hotstab which can be displaced into a connection block associated with a subsea installation. The hotstab is normally provided with several passages for different fluid circuits. Conduits in the hotstab are a complementary fit to corresponding conduits in the connection block when the hotstab is in the operative position in the connection block.

This type of hotstab is largely standardized and well known to a person skilled in the art.

Transmission of electrical signals between an ROV and a subsea installation has been difficult to accomplish in cases where the connection has had to be made under water. So far, such ROV-operable connectors have been disproportionally large and expensive, and the connection has involved a considerable risk of damage to the electrical contact surfaces . Noncontact connection of electrical transmissions has been characterized by poor efficiency, with subsequent problems connected with among other things seals and overheating. So far, this has prevented the use of electrical energy transmissions in connection with this type of hotstab.

The object of the invention is to remedy or reduce at least

one of the drawbacks of prior art

The object is achieved in accordance with the invention, through the characteristics stated in the description below and in the subsequent claims .

On a hotstab for use under water, where the hotstab is a complementary fit to a submerged connection block, and where the hotstab comprises passages for conveying pressurized fluid, there is provided a first transformer section. A second transformer section, which in the operative position cooperates with the first transformer section, is located at the connection block. The transformer sections provide noncontact transmission of electrical energy.

The noncontact transmission of energy is inductive and may be used for both signal transmission and power transmission.

Preferably the transformer sections are made to be mechanically pushed into each other or against each other, at least one of the first transformer section or the second transformer section advantageously being arranged in a rubber-like material.

It is obvious to a person skilled in the art that the open gap between the first transformer section and the second transformer section must be as narrow as possible to achieve the highest possible efficiency for the energy transmission. Moreover, it is crucial to avoid damaging the transformer halves and their relatively small clearances when pushing these into each other or against each other.

Preferably the transformer halves are arranged such that the transformer halves are not pushed into or against each other until after the hotstab is properly guided in the connection block.

As mentioned above, it has proven expedient to arrange at least one of the transformer halves in a rubber-like, flexible material so as to allow clearances to be kept relatively small without risking damage to the transformer halves. Even if the transformer halves were accidentally to come into contact with the opposite transformer half or another body, the transformer half in question will be able to displace slightly in a resilient manner, thus avoiding being damaged.

Embedding transformer halves in a flexible material is not obvious to a person skilled in the art, among other things because a person skilled in the art would anticipate problems of overheating in the transformer halves.

The flexible material may at least partly consist of elastomers such as polyurethane, natural rubber or synthetic rubber.

The device of the invention provides a simple and novel solution for parts for noncontact transmission of energy and presents a practical design for fastening of the transformer halves .

The following describes a non-limiting example of a preferred embodiment illustrated in the accompanying drawings, in which:

Fig. 1 is a schematic sectional view of a connection block, where a hotstab is in the process of being pushed into the connection block, and where means of noncontact transmission of energy in accordance with the invention is provided in connection with the connection block and the hot stab, respectively; and

Fig. 2 is a schematic view of the connection block and the hotstab of figure 1 after they have been connected up.

In the drawings , reference number 1 denotes a hotstab connected to an ROV (not shown) by an ROV mounting 2, the hotstab 1 being arranged for displacement into a connection block 4 associated with a subsea installation (not shown) .

The hotstab 1 is provided with passages 6 that communicate with the ROV (not shown) in a manner that is known per se. When in the operative position in the connection block 4, the passages 6 are sealingly encapsulated by seals 8. Each passage 6 corresponds with a respective conduit 10 in the connection block 4.

The hotstab 1 is provided with a first transformer section 12, the transformer section 12 of this preferred embodiment encircling the hotstab 1 near the ROV mounting 2.

The first transformer section 12 comprises a first transformer coil 14 and first transformer armature 16. The first transformer coil 14 is connected to the ROV (not shown) via a first pair 18 of conductors that passes through an opening 20 in the hotstab 1.

The first transformer section 12 is disposed in an encircling first groove 22 in the hotstab 1.

Opposite and corresponding to the first transformer section 14, when this is in the operative position, there is provided a second transformer section 24 in a second groove 26 located in the connection block 4.

The second transformer section 24 comprises a second transformer coil 28 and second transformer armature 30. The second transformer coil 28 is connected to the subsea installation (not shown) via a second pair 32 of conductors that passes through an opening 34 in the connection block 4.

The first transformer section 12 and the second transformer section 24, constructed in accordance with NO 320439 and thus not explained in any greater detail herein, are both disposed in a rubber-like material 36.

In this preferred embodiment the rubber-like material 36 is made of an elastomeric mouldable material such as polyurethane .

A number of other elastomeric materials based on rubber and synthetic fibres may be used, and these may be adapted for the purpose through e.g. moulding or machining . The important thing is that the material (s) selected has a resilient effect .