The present invention relates to a seal retainer device adapted to be received in a bore in a structural body part designed to be submerged in water.

Even if the present seal retainer device is developed in conjunction with a connection assembly adapted for connection of two circular or pipe-shaped elements, which connection exhibits a predetermined pre-tension, other usages are conceivable. In this particular example the connection assembly is an emergency disconnection package (EDP) which resides between components in association with a subsea well, such as between a lower part of a riser and the upper part of a lower riser package (LRP). Reference is given to NO 201 1 0380 (PCT/EP2012/001045) for such EDP and LRP. The problem the present invention is to solve, is how to retain a seal in position on a submerged first structural body part when such first structural body part is separated from a second submerged body part, and then be able to replace such seal by means of a diver or an ROV when the body parts are separated, and then be able to reenter and align the two body parts into sealingly engagement having the new seal therebetween.

This is solved according to the present invention by a seal retainer device of the introductory said kind, which device is distinguished in that said seal retainer device comprises a locking pin adapted to be movable between a retracted and extended position in said bore, which locking pin is biased by resilient means into said extended position and is actuatable into said retracted position when the seal is to be released.

Preferably the locking pin comprises a passage therethrough which provides water communication between the bottom of the bore and the surrounding water. In one embodiment the pin is actuatable by means of hydraulic pressure supplied to said bore. It is also conceivable that the pin can be actuated manually by a diver, perhaps with the aid of a tool. In one embodiment the pin includes an annular piston having a first and a second end surface, said first end surface acting against a ledge surface arranged on said pin, said second surface being acted upon by said hydraulic pressure enabling the pin to retract into said bore against the force of said resilient means.

In one preferable embodiment the resilient means is a spring, but any conceivable spring acting means could possibly work.

Preferably an outer seal is arranged between the bore wall and the annular piston, and an inner seal is arranged between the inner surface of the annular piston and the pin.

In one embodiment the seal retainer device is secured to the structural body by means of a retaining and pin guiding means threaded into said structural body.

Preferably a second outer seal is arranged between the retaining and pin guiding means and the bore wall, and a second inner seal is arranged between the retaining and pin guiding means and the pin. In still another embodiment the structural body includes a passage leading into the bore in order to supply hydraulic pressure against said ledge on the pin, said passage ending in a chamfered surface at the bore.

In still another preferable embodiment the retainer pin is enabled to perform a snapping action when a structural body that includes at least one subsea seal retainer device is lowered against a second structural body carrying a seal to be retained. Preferably the retainer pin is extending in an inclined direction relative to the surfaces that define the interface between the body parts.

Example of embodiment

While the various aspects of the present invention has been described in general terms above, a more detailed and non-limiting example of an

embodiment will be described in the following with reference to the drawings, which Fig. 1 is a schematic view of a subsea connector assembly, into which a seal retainer device according to the present invention can be installed; Fig. 2 is a cross section view of an upper part of the connector assembly; Fig. 3 is an enlarged cross section view of a part of such connector;

Fig. 4 is a cross section view of the connector landed onto a hub;

Fig. 5 is a connector similar to the connector of fig. 4, and with the seal

retainer device according to the invention installed and shown;

Fig. 6 is a longitudinal cross sectional view of the seal retainer device

according to the invention in engaged position, and

Fig. 7A and 7B are longitudinal cross sectional views of the seal retainer device according to the invention in disengaged position.

One possible application of the seal retainer device according to the present invention is, as mentioned, on a subsea connector, which is described here as an example of one type of usage of the seal retainer device according to the invention. By such usage, preferably two seal retainer devices would have been installed in opposition to each other, i.e. diametrically to each other relative to the seal itself.

Such a subsea connector can be in form of an emergency disconnection package (EDP), arranged to the lower end of a riser and making the connection between the riser and a lower riser package (LRP). Fig. 1 is a schematic view of such a setup. A wellhead 3A extends up from a seabed 1 A and is connected to a Xmas tree 5A. On top of the Xmas tree 5A is arranged a lower riser package 7A and to the lower riser package 7A there is connected a riser 9A which extends up to a surface vessel (not shown). Making the connection between the riser 9A and the lower riser package 7A (LRP) is an EDP 1 1A. In the setup in Fig. 1 is only one of a plurality of possible usages of a seal retainer according to the invention. Hence, such a seal retainer can be used to retain a seal in a plurality of various components, as will be apparent for the person skilled in the art. Fig. 2 shows a connector 100. The connector 100 could for instance be used as the EDP 1 1 A shown with reference to Fig. 1 . Regardless of its particular employment, the function and components of the connector 100 will be described in the following. The connector 100 has a main body 101 which in its upper end is arranged to be connected to a lower end of a riser section (not shown) or other equipment by means of a plurality of bolts 103. At the lower portion of the main body 101 a groove 105 extends about its periphery. The groove 105 is adapted to receive the upper parts of a plurality of collet fingers 107. In this embodiment there are arranged 12 collet fingers 107 about the lower circumference of the main body 101 . The collet fingers 107 exhibit a locking profile 109 at their lower section. The locking profiles 109 face radially inwards and are adapted to engage with a facing profile of a hub to which the connector 100 will connect. This will be described further below.

Between the collet fingers 107 guiding plates 1 1 1 are arranged, which plates 1 1 1 contribute to retain the collet fingers 107 in place and guide them when they are moved radially. As will appear from the description further below, the collet fingers 107 are arranged to pivot about their section of engagement with the groove 105 in the main body 101 . In Fig. 2, the collet fingers 107 are shown in a position in which their lower part is pivoted radially outwards.

In order to pivot the collet fingers 107 radially inwards and outwards there is arranged an actuating sleeve 1 13. The actuating sleeve 1 13 is adapted to be moved upwards and downwards, thereby pivoting the collet fingers 107, in particular the locking profile 109 of the collet fingers 107, outwards and inwards.

In Fig. 2 and Fig. 3, the actuating sleeve 1 13 is shown in an upper position. In this position, an unlocking shoulder 1 13a (Fig. 3) engages an unlocking shoulder 107a of the collet finger 107, thereby providing an outwardly pivoting movement of the collet finger 107, about its engagement with the groove 105 in the main body 101 . Fig. 4 shows a cross section view of the connector 100, along another plane than shown in Fig. 2 and Fig. 3. In this drawing the connector 100 is shown landed onto a landing face 203 of a connecting part, however not yet connected to it. Here the connecting part is in form of a hub 201 . Here one can see how the actuating sleeve 1 13 has pivoted out the collet fingers 107. One can also see the entire cross section profile of the collet fingers 107, without the guiding plates 1 1 1 in front. The hub 201 comprises locking profiles 209 extending about its upper periphery, adapted to engage with the locking profiles 109 of the collet fingers 107. The actuation sleeve 1 13 comprises an inclined actuation face 1 13b which is adapted to slide against a facing and inclined collet actuation face 107b of the collet finger 107. These inclined faces 1 13b, 107b provide the inward pivoting movement of the collet finger 107 when the actuation sleeve 1 13 is moved downwards. The collet finger 107 and the actuation sleeve 1 13 also have vertical faces that face each other when in a locking position.

In fig. 4 it is also indicated a seal 5 at the interface between the two connecting parts, the main body 101 and the hub 201 . The seal 5 is to be retained by a seal retainer device (not shown in fig, 4) according to the present invention. The seal retainer device is described below with reference to fig. 5, 6 and 7.

Fig. 5 shows in large the same as fig. 4, but now the seal retainer device 10 is installed. The seal retainer device 10 is installed in a bore 6 drilled into the main body 101 of connector 100. The main structural body part 101 includes a passage 9 leading into the bore 6 in order to be able to supply hydraulic pressure into the bore 6. This will be described in closer detail with reference to fig. 6 and 7.

As mentioned, the seal retainer device 10 is adapted to be received in a bore 6 in the main body part 101 designed to be submerged in water. The seal retainer device 10 is designed to engage and retain the seal 5, or seal assembly, arranged to the main body part 101 , like the EDP connecting part 101 above.

As shown in more detail in fig. 6, the seal retainer device 10 comprises a locking pin 1 that is adapted to be movable between a retracted and extended position in the bore 6 of the structural body part 101 . The locking pin 1 is biased by a spring 4 into the extended position and is actuatable into the retracted position when the seal 5 is to be released. In the shown embodiment, the bore 6 and the pin 1 are extending in an inclined direction relative to the surfaces that define the interface between the body part 101 and hub 201 .

As shown in figure 6, 7A and 7B, the locking pin 1 has an axial passage 7 through its entire extension. This passage 7 provides water communication between the bottom 6a of the bore 6 and the surrounding water.

In the illustrated embodiment, the pin 1 is actuatable by means of hydraulic pressure supplied to the bore 6. However, it is also conceivable that the pin 1 can be actuated manually by a diver, perhaps with the aid of a tool.

In the illustrated embodiment, the pin 1 includes an annular piston 3 having a first and a second end surface 3a, 3b. The first end surface 3a is acting against a ledge 8 surface 8a arranged on the pin 1 . The second surface 3b can be acted upon by hydraulic pressure enabling the pin 1 to retract into the bore 6 against the force of the spring 4. However, any conceivable spring acting means could work. This is illustrated in fig. 7B. Moreover, an outer seal 3c is arranged between the bore wall 6b and the annular piston 3, and an inner seal 3d is arranged between the inner surface of the annular piston 3 and the pin 1 . In the illustrated embodiment the seal retainer device 10 is secured to the structural body part 101 by means of a retaining and pin guiding means 2 threaded into said structural body part 101 via meshing threads 2a.

A second outer seal 2b is arranged between the retaining and pin guiding means 2 and the bore wall 6b, and a second inner seal 2c is arranged between the retaining and pin guiding means 2 and the pin 1 .

Preferably the structural body part 101 includes a passage 9 leading into the bore 6 in order to supply hydraulic pressure against said ledge 8 on the pin 1 . As shown in fig. 5 this passage 9 is ending in a chamfered surface 9a at the bore 6.

It is to be noted that the retainer pin 1 is enabled to perform a snapping action when a structural body part 101 that includes at least one subsea seal retainer device 10 is lowered against a second structural body part 201 carrying a seal 5 to be retained. This is illustrated in fig. 7A. Alternatively, the seal 5 can be raised into the structural body 101 , either manually, by tool or by ROV.

Thus this spring loaded, hydraulically operated seal retainer pin 1 will automatically engage and retain seals/seal assemblies 5 when the equipment in which they are installed is lowered onto them, or brought into them as above indicated. The pin 1 is disengaged by actuating the hydraulic line, allowing the seals to be released. A piston sleeve ensures the mechanism is pressure balanced and prevents the pin from being pushed in any direction by the external (ambient) pressure. The spring exerts enough force on the pin to prevent it from being pushed back by the column of hydraulic fluid in the hydraulic line which extends above sea level.