EP2223400A1

EP2223400A1 - Subsea containment vessel and heat sink assembly

Info

Publication number: EP2223400A1
Application number: EP08860632A
Authority: EP
Inventors: William Brown
Original assignee: Aker Subsea Ltd
Current assignee: Aker Solutions Ltd
Priority date: 2007-12-12
Filing date: 2008-12-02
Publication date: 2010-09-01
Also published as: GB0724286D0; WO2009074770A1

Abstract

A subsea containment vessel includes a heat sink assembly comprising a cage comprising a plurality of pillars (2) and between at least one pair of adjacent pillars a heat sink in the form of an interface plate (3) having an outer surface for engagement with the containment vessel. The plate has lateral faces each of which has a slanted profile for sliding movement relative to a complementary profile on an adjacent side face of a pillar. The profiles may comprise a rail (6) on a lateral face of the plate and a corresponding slot (7) in an adjacent side face of a pillar (2). Any suitable means may be employed to provide a tensile or compressive force for moving the interface plate into close contact with the vessel. They may include a threaded tumbuckle, a hydraulic piston or a clamp which might be manual and may be self-locking.

Description

SUBSEA CONTAINMENT VESSEL AND HEAT SINK ASSEMBLY

Field of the invention

This invention relates to subsea assemblies such as subsea modules which are employed in association with subsea wells. These modules normally comprise a variety of devices for the control of fluids to and from the wellhead and more recently for providing communication and remote control.

Background to the invention

It is now customary for subsea equipment to include electrical equipment for communication and/or control. It is customary for such electrical equipment, which may comprise motors, electrically operated actuators, and/or other electronic devices and circuits, to be disposed in a containment vessel.

In practice the only reliable means of dissipating the heat inevitably generated by the electrical equipment is by conduction and therefore an efficient heat-sink is necessary.

The technical problem is to achieve close contact with the wall of the containment vessel without the use of, for example, bolts or other devices which pierce through the wall of the containment vessel.

One known proposal for this purpose, published as WO2006/019037, provides a cage within which the electrical equipment is disposed, the cage including plates which are disposed in contact with an outer receptacle. The plates are arranged between a base dish and a connection dish which are connected by bolts which draw the dishes together and force the plates outwardly. Such an assembly can provide good thermal contact but imposes various constraints on the design and is difficult to adjust in use.

The state of the art also includes the documents GB-A-2317686, which discloses a heat sink attached to a central tube, and WO01/13692-A1, which discloses heat conducting plates which are placed against the inner wall of the shell of the pressure vessel. Summary of the invention

The invention in a preferred form comprises two main parts. One part is a frame which is intended to fit closely within a containment vessel. The frame includes pillars, which in a typical embodiment are parallel and are spaced apart in a circle, on the assumption that the containment vessel is generally cylindrical. Another part is at least one heat sink which is in the form of an interface plate that fits between two adjacent pillars. The lateral faces of the plate and the corresponding side faces of the pillars have complementary profiles which are disposed at a slant with respect to the plate and pillars, so that the plate can move into position between the pillars only at an acute angle relative to the general plane of the plate, so that there is a component of movement normal to the outer surface of the plate and a component of movement parallel to that surface.

There may be only one plate but the frame may be designed to accommodate a plurality of such plates either in a symmetrical or an asymmetrical arrangement.

The complementary profiles may comprise at least one oblique rail on each lateral face of the plate and a corresponding slot in the adjacent pillar.

The invention extends to a containment vessel including an assembly as indicated above and a subsea module including such a containment vessel and heat sink assembly.

There follows a description of a particular embodiment by way of example and with reference to the drawings.

Brief description of the drawings

Figure 1 is an explanatory diagram showing part of one embodiment of the invention;

Figure 2 illustrates a cage including heat sink interface plates;

Figure 3 is a sectional view showing the upper part of a containment vessel including an internal frame and heat sink interface plates; Figure 4 is a vertical section through the containment vessel showing heat sink interface plates in retracted positions;

Figure 5 is a vertical section through the containment vessel showing heat sink interface plates in extended positions;

Figures 6A and 6B are simplified front and side views the heat sink assembly in which the heat sink is in a retracted position; and

Figures 7A and 7B are simplified front and side views of the heat sink assembly in which the heat sink is in an extended position.

Detailed description of a preferred example

Figure 1 illustrates part of a cage 1 which comprises a multiplicity of pillars 2 which are spaced apart and may form a circle, as described with reference to the later Figures. Between two adjacent pillars fits an interface plate 3 which constitutes the body of a heat sink for electrical and/or electronic equipment (not shown). The interface plate is in this embodiment generally rectangular with a curved outer face 4 so that it conforms to the (preferably) curved inner surface of a cylindrical containment vessel (Figures 3 - 5).

Each lateral face (such as the side face 5) of the interface plate 3 is provided with a slanting rail 6 which can slide in a correspondingly slanted slot 7 in the adjacent side face 8 of a pillar 2. The complementary profiles thus formed constrain the movement of the plate 3 relative to the pillars such that it can move only with a component of movement normal to the outer face and a component parallel to the outer face (i.e. in the general plane of the plate).

The arrangement allows the outer surface of the heat sink constituted by the interface plate 3 to be kept substantially within the extent of the cage. This is beneficial during assembly because the risk of damage to the outer surface of the heat sink is lessened. Moreover the arrangement provides a mechanical advantage (depending on the angle of the rails 6 and slots 7) for urging the outer face into contact with the containment vessel. The force applied to move the interface plate 3 may be tensile or compressive, whichever is more convenient having regard to the arrangement of other components that are to be fitted inside the containment vessel. Any suitable means may be employed to provide the tensile or compressive force for moving the interface plate into close contact with the vessel. They may include a threaded turnbuckle, a hydraulic piston or a clamp which might be manual and may be self- locking. An example is shown in Figures 6A - 7B.

The rails 8 need not be of the same material as the interface plate 3 because their function is load-bearing rather than thermal conduction.

Figure 2 illustrates one example of the heat sink assembly. The pillars 2 are disposed spaced apart around a circle to form a generally cylindrical cage with a top ring 9 and a base ring 10 between which the pillars extend. Figure 2 shows three interface plates 3 each in position between a respective pair of adjacent pillars.

Figure 3 illustrates the upper part of a containment vessel 12 including a heat sink assembly according to the invention. It has in this example the form of a domed cylinder. The interface plates 3 are in 'retracted' positions spaced away from the inner surface 13 of the cylindrical wall of the vessel 12 by a gap 14.

The vessel 12 may be fitted in any convenient known manner to a base plate with which the vessel 12 makes sealing engagement so that the interior of the vessel may be maintained at some suitable pressure (e.g. atmospheric pressure) usually much less than the external pressure of the surrounding medium (i.e. seawater) when the vessel 12 is submerged.

The containment vessel 12 would usually be mounted upright on or within a subsea module in a manner generally known in the art.

Figure 4 is a vertical section through the containment vessel 12, again showing the interface plates 3 spaced from the inner surface 13 of the cylindrical wall of the vessel 12. Figure 5 is a vertical section through the containment vessel showing the interface plates in their extended positions, closely adjacent the inner surface 13 of the cylindrical wall of the vessel 12.

Figures 6A and 6B are a front view and a side view of part of the assembly, showing a single heat sink between pillars 2. A connecting rod 15 connects the lower edge of the heat sink plate 3 to a tensioning bolt 16 which passes through the base ring 10 and can be adjusted by a nut 17. In Figures 6A and 6B the heat sink 3 is in the retracted position, there being the gap 14 between the plate 3 and the inner surface of the wall of the pressure vessel 12.

Figures 7A and 7B are views similar to Figures 6A and 6B but show the plate 3 in the extended position, the adjustment of the nut 17 on the tensioning bolt 16 having caused the connecting rod 15 to pull the heat sink 3 obliquely into contact with the wall of the pressure vessel 12.

Claims

1. A cage for accommodation within a subsea containment vessel, comprising a plurality of pillars (2) and between at least one pair of adjacent pillars a heat sink in the form of a plate (3) having an outer face (4) for engagement with the containment vessel, the plate having lateral faces (5) each of which has a slanted profile (6) for sliding movement relative to a complementary profile (7) on an adjacent side face (8) of a pillar (2), whereby movement of the plate (3) relative to the pair of pillars is constrained to have a component normal to the said outer face and a component parallel to said outer face.

2. A cage according to claim 1 in which the profiles (6, 7) comprise a rail (6) on a lateral face of the plate (3) and a corresponding slot (7) on an adjacent side face of a pillar (2).

3. A cage according to claim 1 or claim 2 in which the pillars (2) are parallel and are spaced apart in a circle.

4. A subsea containment vessel (12) which includes a cage according to any of claims 1 - 3, wherein the vessel has a wall of which an inner surface (13) conforms to the outer face (4) of the plate (3).

5. A subsea containment vessel (12) according to claim 4 and further comprising means for moving the plate (3) to bring the outer face (4) thereof into close contact with the inner surface (13) of the containment vessel.

6. A subsea containment vessel (12) according to claim 5 in which the said means for moving comprises a tensioning link (15 - 17) coupled to the plate (3).

7. A subsea module comprising a containment vessel according to any of claims