Movable-point device for connecting a sea-bed exploitation column to its base connecting and disconnecting processes using the said device and joint element used in the said device

(74) Agent

Tandbergs Patentkontor AS, Oslo.

(56) Cited publications

Norwegian (NO) patent application no. 772555 (PL § 2.2.3),

Norwegian (NO) Publication No. 143637

The present invention relates mainly to a device which forms a universal joint connection for the column of a working platform on the seabed with its support, a method of connection and a method of release using such link connection.

It is already known a device for universal joint connection of a column for a working platform on the seabed with its substrate placed on the seabed. This type of device has heretofore consisted of metallic parts and formed a cardan-type joint.

However, such a type of linkage has an organic structure which is relatively complex and the operations of connecting and releasing the column from its substrate are relatively time consuming and sometimes difficult to perform and are thus costly because they require considerable work effort. In addition, the metal parts of the joint are subjected to corrosion from the seawater, which could reduce the life of such a joint and necessitate considerable maintenance work besides subjecting the joint to compression and / or tensile forces which are significant during the oscillations of the column and thus cause wear on the parts.

SUMMARY OF THE INVENTION It is thus the object of the present invention to eliminate the aforementioned disadvantages of providing a solution which allows a very fast connection and release of a column in relation to its substrate, as well as a satisfactory life and relatively simple construction.

According to the invention, this solution consists in a device for universal joint connection of the column of the working platform on the seabed with its substrate disposed on the seabed and the invention is characterized by an annular joint element of elastically deformable material arranged on the base of the column and in an annular space arranged in the column base. The deformable elastic member preferably has an annular shape, is secured substantially coaxially to the base of the column, and has a radially projecting circumferential portion which can be secured and blocked at least in a lateral direction in a corresponding space in the substrate, preferably by biasing.

The elastically deformable member preferably has a free-tensioned or in the working position fixed in a vertical position in the column, a substantially symmetrical shape with respect to the longitudinal axis of the column and preferably mainly a rotary body about said longitudinal axis, in particular having a shape which is in the smallest approximately cone-shaped, e.g. in the form of a tulip or bell. According to a particular embodiment thereof, the elastically deformable member in its mass comprises at least one inner annular space preferably provided with at least one outlet opening for permanent connection with the surrounding environment.

According to another particular embodiment, this device comprises selectively actuated forcing means intended for substantially radial at least partial contraction of the radially protruding annular portion mentioned above and these forcing means are either embedded in the element or externally thereon.

According to yet another particular embodiment of this device, the resiliently deformable member comprises external radial incisions which delineate segments having a common base.

The present invention also relates to a method of connecting a jointed column, in particular a float with its support, and this invention is characterized in that it comprises the following successive operations:

- guiding the column with its elastic element in position substantially vertically above the space in the substrate,

- insertion of the column foot into this space, especially when ballasting the column, until said elastic element has passed the edge of the space, and

- exerting an upward force on the column, in particular by balancing it so that the element will come into contact with said edge.

Also, the present invention relates to a method for disengaging the column, which method is characterized in that it comprises the following successive operations:

- pushing the foot of the column into its space, especially when ballasting the column, until the foot touches the bottom of the room,

- influence of the coercive means until the element can pass at least partially the edge of said space, and

- exerting an upward force on the column, especially by balancing it, until the said elastic element has passed said edge and will be completely outside the room and thus have pulled the foot of the column out of the room.

Finally, the present invention comprises, as a purely new industrial product, a joint compound formed of a portion molded at least partially as a monoblock and which mainly forms the said joint connection device.

Further objects, advantages and features of the present invention will become more apparent from the following description with reference to the schematic drawings showing two embodiments which are really preferred and which are given by way of example only. 1 is a schematic view of a column connected to the seabed with its substrate placed on the seabed, in vertical position, provided with a linkage device according to the invention; FIG. 2 is a partial sectional view on a larger scale of the portion of FIG. 1, which is circled and designated II, showing a first embodiment of the device according to the invention; FIG. 3 is a sectional view of another embodiment of the device in accordance with the invention; FIG. 4 is a partial sectional view similar to FIG. 2 and shows the column in an oblique position with deformation corresponding to the joint connection; FIG. 5 is a partial sectional view showing the phase of connecting the column with its support to the elastically deformable member of the device according to the invention shown in FIG. 2, partially recessed into the bed space; FIG. 6 and 7 are partial sections showing different phases during work on disabling f

the column from its substrate, and fig. 8 shows a variant of the device comprising the outer forced members of the joint.

Referring to FIG. 1, a column T. for a working platform and provided with a float 2 comprises a device 3 according to the invention with universal joint connection between it and its support 4 arranged on the seabed 5.

Referring to FIG. 2 in particular formed by an element 6 constituting a joint of elastically deformable material interposed between the foot 7 of the column 1 and the support 4 by being connected to each of these means respectively.

The element 6 preferably has an annular shape and is secured substantially coaxially to the foot 7 of the column 1 and has a radially protruding circumferential portion 8 which can be secured and blocked at least in a lateral direction in a corresponding space 9 in the support 4, preferably by biasing. Preferably, the resiliently deformable member 6 has a free and unstressed state or in working condition mounted in vertical position of the column a substantially symmetrical shape with respect to the longitudinal axis XX of the column 1 and preferably mainly in the form of a rotary body about the same longitudinal axis XX. especially a shape which is at least approximately blunt cone-shaped, e.g. in the form of a tulip or clock. The shape of the elastically deformable member 6 in the mounted state in the working position is preferably that shown in the drawings, this form being part of the invention with regard to the particular embodiment of the member 6.

In addition, the elastically deformable member 6 in its mass may comprise at least one inner annular space 10, which is preferably provided with one or more drain openings 11 for permanent connection with the surrounding environment.

Likewise, the device 3 may comprise selectively actuated forcing means intended for substantially radial contraction at least in part by the annular radially protruding portion 8 of the member 6 and these forcing means are either embedded in the member 6 or externally thereof.

The forcing means preferably comprises an annular inflatable cavity 12 which is in the mass of the element 6 between the inner cavity 10 and the radially outer edge 13 of the element 6, in particular near the underside 14 of the circumferential edge 13 of the element 6. The cavity 12 is substantially flattened in normal position for operation of the element, as shown in FIG. 2.

According to another embodiment of the elastically deformable member shown in FIG. 3, this radial exterior incision 15 comprises segments defining between them such as 16, 17, 18 having a common bottom 19. Preferably, each element 16, 17, 18 comprises an inflatable cavity forming said forceps located on the underside of the circumferential edge, respectively. 20, 21, 22 of said segment.

According to another variant shown in FIG. 8, the forcing means is an annular inflatable casing 34 affixed to a movable holder (such as the inner side surface 35 of the compartment 9) which coaxially surrounds the member 6 and, upon inflation, can come into contact with the same.

Moreover, and as seen from FIG. 2, the space 9 in the substrate is formed by a receiver cavity 24 having a shape cooperating with that of the elastic member, e.g. substantially cylindrical, the diameter of which is greater than that of the foot 7 of the column 1, but is smaller than the largest diameter of the element 6 in the free state without tension, so that in the assembled state it will be either secured with force, the receiving cavity 24 comprising means for blocking and locking 25 of the element 6. The blocking means 25 is preferably formed by an annular member internally and near the upper end 26 of the cavity 24 against which the protruding peripheral portion 13 of the element 6 may come into contact.

Likewise, the receiver cavity 24 has a bottom 27 e.g. having a substantially concave butt cone shape and the substrate 4 comprises a bore 28 with an axis which coincides substantially with the axis XX of the column in its mounted vertical position, and opens into the receiver cavity 24 and connects it to the seabed 5. This bore 28 thus has its axis also coincides with the axis of the aperture 29 arranged in the interior of the column in its mounted vertical position, which aperture 29 in a well known manner permits particular passage of working pipelines for examining layers located in the seabed.

Likewise, the free end 30 of the foot 7 of the column 1 preferably has a convex blunt cone shape which mainly cooperates with the shape of the bottom 27 of the space 9 mentioned above, whereby the same end is intended for temporary contact e.g. as shown in FIG. 6. For this purpose, the end 30 of the foot 7 of the column 1 may be provided with a buffer element 31 such as e.g. are annular in one piece or divided into segments.

The column foot 7 may also comprise means for inserting the member 6 which makes this member movable in the axial direction XX of the foot 7 of the column 1 and comprising an annular shoulder 32a fixedly connected to the foot 7 and a locking ring 32b attached to the foot itself.

The operation of this column described above in the mounted state is as follows with reference to FIG. 4:

When the column 1, due to its float 2, swings under the action especially of waves and winds, the circumferential edge 13 of the element 6 is subjected to a bend whose amplitude varies along the circumference of the outer edge 13. This bend is minimal on the side where the column is inclined and is maximum at the opposite side. The softness of the element 6 is enhanced by the presence of the interior space 10 which can be emptied by means of the drain openings 11 of water it contains, as shown in FIG. 4. Moreover, thanks to the blocking means 25, the circumferential edge 13 of the element 6 cannot accidentally push out of the space 9 in the substrate 4.

Moreover, and thanks to this elastically deformable member 6, the operations of connecting and releasing the column 1 from its support 4 are very easy, as will be explained below.

Referring to FIG. 5, the connection of the column 1 with the float 2 with its support 4 comprises the following successive operations:

The column 1 is provided with its elastic element 6 in position substantially vertically above the space 9 in the substrate 4. The foot 7 of the column 1 is lowered into the space 9, especially by ballasting the column, until the elastic element 6 has completely passed the upright edge 33 of compartment 9 by elastic deformation. The passage of the upright edge 33 by means of the elastic member 6 is likewise facilitated by the inner cavity 10 which allows the elastic deformation of the member 6 to increase. When the element 6 comprises outer radial incisions as shown in FIG. 3, these incisions facilitate the elastic deformation of the member 6.

Finally, an upward force is exerted on the column 1, especially by balancing the same, so that the element 6 will come into contact with the blocking means 25 as shown in FIG. 2.

Referring to FIG. 6 and 7, the release of the column comprises the following successive operations:

The foot 7 of the column 1 is lowered in its space 9, especially by ballasting the column 1, until the foot 7 comes into contact with the bottom 27 of the room 9 (see Fig. 6). The forced organs such as is formed by the annular cavity 1'2 of FIG. 6, until the element 6 can pass at least a portion of the edge 33 of the abutment means 25 in the space 9. An upward force is then exerted on the column, in particular by balancing it, which causes the elastic member 6 to abut against the edge 33 of the abutment members 25, a portion of the outer edge 13 of the element 6 having passed the upright edge 33 on the abutment means 23 thanks to the radial contraction caused by inflation of the annular cavity 12. The air is released from the cavity 12 which makes it possible to completely pass the elastic member 6 past the edge 33 of the abutment means 25 under the action of the upward force caused by balancing the column. The element 6 is then completely out of the chamber 9 and thus permits the extraction of the foot 9 of the column from the room 9. The release of the column from its substrate is thus completed.

In the case where said forcing means is formed by an annular inflatable casing 34 attached to a holder movably disposed outside and coaxially surrounding the member 6, a radial contraction operation of the member 6 is performed so that the outer edge 13 of the member can pass at least partially the upright edge 33 of the abutment means 25 (see FIG. 8).