IE63699B1

IE63699B1 - Clamping system and clamps for the clamping and the subsequent remote release of an underwater structure

Info

Publication number: IE63699B1
Application number: IE224989A
Authority: IE
Inventors: Umberto Giovannini
Original assignee: Saipem Spa
Priority date: 1988-07-29
Filing date: 1989-07-12
Publication date: 1995-05-31
Also published as: LU87558A1; NO893061D0; PT91298B; BE1003076A4; SE8902577D0; NL8901920A; IT8821554A0; ES2014915A6; IE892249L; FI893552A; PT91298A; DE3923957C2; CA1337580C; BR8903700A; DE3923957A1; DK170911B1; SE8902577L; FI893552A0; FR2634854A1; GB8916205D0

Abstract

A system for the progressive remote release of a series of clamps clamped in succession along an underwater structure, comprising a withdrawal rope 20 which has a special enlargement 21 at one end and is made to pass through the central through bore 17 in the connection pins which lock the clamps of the series, said pins being in the form of two coupled half-pins 15, 16 the enlargement to be freed to engage the next clamp. A method for operating the release system is also provided.

Description

CLAMPING SYSTEM, AND CLAMPS, FOR THE CLAMPING AND THE SUBSEQUENT REMOTE RELEASE OF AN UNDERWATER STRUCTURE This invention relates to a clamping system, and clamps, for the clamping of an underwater structure and for the subsequent remote release thereof, without the need to use divers.

When conveying pipeline portions or other underwater structures through distances of up to several kilometres to the site in which they are to be installed on the bed of an expanse of water, it is known to generally use support floats which are arranged in succession and individually connected to the structure to be supported by means of clamps, ropes or other means, which have then to be released when the operation has been completed.

In the current state of the art this release stage is carried out by divers or remotely guided vehicles which directly release each element one after the other.

This method however is not only very costly in terms of time and money, but is also very risky in terms of the safety of the operators who personally have to release the connections. Devices are occasionally used which dispense with the direct action of the operators by releasing the clamps remotely using acoustic signals, but a release system of this type is of such high cost that its use cannot always be justified.

The object of the present invention is to obviate the above drawbacks by providing an effective clamping system which enables a series of clamps clamped in succession along an underwater structure to be released remotely in sequence in an economical and rapid manner, without the need to use divers.

According to the present invention, there is provided a clamp for the clamping of an underwater -2structure, comprising two jaws which are pivotally connected together in opposing positions at one of their ends by a mechanism for adjusting the tension by which the clamp clamps said underwater structure, and are connected together at their other ends by a joint comprising a groove portion and a tongue portion which are lockable by a through connection pin, wherein the through connection pin is in the form of two half-pins which together define a central through bore through which there can be passed a rope, cable or the like having at one end an enlarged portion of a size greater than the diameter of said central bore of the pin but smaller than the diameter of the pin itself.

The present invention also provides a clamping system for the clamping of an underwater structure and for the subsequent remote release thereof, comprising (a) a plurality of clamps of the invention, and (b) a single rope, cable or the like, having at one end said enlarged portion, passing through the central through bores of the clamps.

The present invention further provides a method of remotely releasing a clamping system of the invention when the clamps of the system are clamped to an underwater structure, which comprises pulling the rope, cable or the like so that the enlarged portion thereof causes the withdrawal in succession of the through connection pin of each clamp.

Preferably, the hollow through connection pin comprises, at that end of its said half-pins located at the side from which the rope, cable or the like is to be withdrawn, a shoulder projection of a size greater than that of the through bore of the joint into which said through pin is inserted.

Preferably, an elastic ring is mounted on the end of the hollow through connection pin at the opposite $ end to that from which the rope, cable or the like is -3to be withdrawn, for holding together the two halfpins .

Preferably, the system further comprises a float connected to the two pivotally connected jaws of each J 5 clamp.

On pulling the rope, cable or the like of the » clamping system, from the surface, the enlarged portion thereof encounters the individual pins and forces them out of their respective joints, withdrawing them also from the elastic rings if provided, thus opening and releasing the clamps of the system in sequence. As the pins are constructed in two parts, as soon as they are withdrawn from their respective joint, the pins open to thus release the enlarged portion of the rope, cable or the like, which is therefore ready to act on the subsequent pins.

The invention will now be described in detail with reference to the accompanying drawings which illustrate a preferred embodiment thereof given by way of non20 limiting example only in that technical or constructional modifications can be made thereto without leaving the scope of the present invention.

For example, instead of being used for the sequencerelease of floats used for supporting a portion of pipeline during its transportation to the site in which it is to be laid on the bed of the water, the clamping system can be used for the sequence-release of ballasts or loads from structures used underwater. In addition, instead of being provided with half-ring jaws particularly suitable for pipelines and cylindrical structures in general, the clamps can be provided with jaws of any shape, and the hollow through connection pins can also be of shapes other than cylindrical.

* Furthermore, a cable or the like can be used instead of a rope.

In the drawings: -4Figure 1 shows the application of a clamping system according to the invention for the transportation of a portion of pipeline by means of floats; Figure 2 shows the operation involving the release of the floats of Figure 1 in succession in order to lay the pipeline portion onto the bed of an expanse of water; Figure 3 is a partial enlarged view of a clamp of the invention; Figure 4 is a longitudinal enlarged view of a portion of the clamp of Figure 3; Figure 5 is a front view of the clamp of Figure 3; Figure 6 is a side view of the clamp of Figure 5; Figures 7 and 8 represent, on an enlarged scale, the steps in the release procedure of the clamps according to the invention.

In the figures the reference numeral 1 indicates a watercraft which by means of a cable 2 tows a pipeline portion 3 to be laid on the bed 4 of an expanse of water. The pipeline portion 3 is supported during its transportation by a series of support floats 5^, 52, . ...5θ which are positioned in succession along the pipeline portion and are locked to this by an analogous series of clamps 6j, 62,....6g and connection cables 7.

Each clamp 6j,.....6θ consists of two jaws 8 and 9 pivoted together at one end and in opposing positions by a mechanism 10 which, by means of a bolt 11 and a nut 12, enables the tension exerted by the clamp in clamping the pipeline portion 3 to be adjusted.

The other two ends of the jaws 8 and 9 are connected together by a pin joint consisting of a groove portion 13 and a tongue portion 14 which are locked by a through connection pin consisting of two half-pins 15 and 16 coupled to each other to form a central through bore 17 (see specifically Figure 8). -5The half-pins 15 and 16 have, at that end facing the watercraft 1, a shoulder projection 18 which prevents the pin from withdrawing towards the right (see Figure 4), and are held together at their other end by an elastic ring 19.

Finally, a withdrawal rope 20 is passed in succession through the central through bores 17 in the pins of the pin joints of all of the clamps .....6θ, one of its ends being held at surface level on the watercraft 1 and its other end having an enlarged portion 21 the size of which is greater than the diameter of the bores 17 but smaller than that of the pins themselves, so that it can be withdrawn together with the pins of the pins joints.

In this manner, by drawing-in the withdrawal rope 20 from the watercraft 1 by pulling it with a certain force 22 (see specifically Figures 7 and 8), the enlarged portion 21 is made to press against the edge of the pin so that, as pulling is continued, it withdraws the pin completely from the respective pin joint, so releasing the respective clamp.

In this manner, all of the clamps 6j,.....6θ can be released from the watercraft 1, since, when the pins have been withdrawn from the pin joints, they fall downwards and release the rope.

Claims

1. A clamp for the clamping of an underwater structure, comprising two jaws which are pivotally connected together in opposing positions at one of their ends by a mechanism for adjusting the tension by which the clamp clamps said underwater structure, and are connected together at their other ends by a joint comprising a groove portion and a tongue portion which are lockable by a through connection pin, wherein the through connection pin is in the form of two half-pins which together define a central through bore through which there can be passed a rope, cable or the like having at one end an enlarged portion of a size greater than the diameter of said central bore of the pin but smaller than the diameter of the pin itself.

2. A clamp as claimed in claim 1, wherein the hollow through connection pin comprises, at that end of its said half-pins located at the side from which the rope, cable or the like is to be withdrawn, a shoulder projection of a size greater than that of the through bore of the joint into which said through pin is inserted.

3. A clamp as claimed in claim 1 or 2, wherein an elastic ring is mounted on the end of the hollow through connection pin at the opposite end to that from which the rope, cable or the like is to be withdrawn, for holding together the two half-pins.

4. A clamping system for the clamping of an underwater structure and for the subsequent remote release thereof, comprising (a) a plurality of clamps as claimed in any of claims 1 to 3, and (b) a single rope, cable or the like, having at one end said enlarged portion, passing through the central through bores of the clamps.

5. A system as claimed in claim 4, further comprising a float connected to the two pivotally -Ίconnected jaws of each clamp.

6. A method of remotely releasing a clamping system as claimed in claim 4 or 5 when the clamps of the system are clamped to an underwater structure, 5 which comprises pulling the rope, cable or the like so that the enlarged portion thereof causes the withdrawal in succession of th-L· through connection pin of each clamp.

7. A clamp as claimed in claim 1, substantially 10 as hereinbefore described with reference to, and as shown in, the drawings.

8. A clamping system as claimed in claim 4, substantially as hereinbefore described with reference to, and as shown in, the drawings. 15

9. A method as claimed in claim 6, substantially as hereinbefore described with reference to, and as shown in, the drawings.