HRP980139A2 - Method and appliance for laying under-water pipes - Google Patents

Description

The invention relates to a procedure for laying underwater pipelines and a device for carrying out this procedure with one floating element system, which consists of a large number of floating elements and fastening devices, for connecting these floating elements with underwater pipelines.

In DE 43 07 922 C1, a procedure is described, in which a pipe, welded to the end on the ground, is pushed onto the water and submerged. Immersion is achieved by means of controlled pipe floatation. Here, a follower tube can be attached to the tube to be submerged in parallel as a swimmer, which will float with it at the same time. The pipe with floating elements must be placed exactly along the direction of installation before submersion. However, the floating elements, together with the pipe, are exposed to significant voltage influences when there is a correspondingly strong undulation. This makes exact placement along the installation direction difficult.

In DE 24 09 962 C3, a procedure is proposed in which the underwater pipelines to be laid are suspended on floating elements in a water depth where there are no undulations. The exact placement of underwater pipelines is thereby greatly simplified. The underwater pipeline itself hangs in the depth of the water where there are no waves and is suspended on floating pipes above the water points. These standing swimming tubes are much less affected by undulations. By releasing the "suspension" of the underwater pipelines on the floating elements, the underwater pipeline is brought to submergence.

Standing floating pipes make it difficult, however, to move underwater pipelines during installation, due to their resistance to water. In addition, floating pipes with an underwater pipeline are naturally attached at only one point.

Especially where the underwater pipe is pushed from the shore into the water, due to this moving and individual connections between the respective floating pipes and the underwater pipelines, difficulties easily arise.

If the installation direction is essentially not correct, then the welding of different parts of the pipe on the surface of the water may be unavoidable, before the entire underwater pipeline is submerged. For stronger bends, suitable special welding arcs are welded in between. The procedure for welding such different parts of pipelines is, for example, described in DE-PS 196 10 526. If such welding is carried out on the surface of the water, then the line must be located on the surface of the water. Hanging on suitable swimming tubes in a water depth free from wave movements is therefore not possible. In order, on the other hand, to enable accurate leveling of finished welded underwater pipelines along the direction of their installation, the use of floating pipes is, however, preferable, for the reasons described above.

The task of the invention, starting from this state of the art, is to make available a device for laying underwater pipelines, with which the exact leveling of total underwater pipelines along the direction of leveling, and before the final immersion, is easily possible and, on the other hand, leveling is not hindered due to standing floating elements.

This task is solved by means of a procedure for laying underwater pipelines with the characteristics of claim 1 and a device for laying underwater pipelines with the characteristics of claim 8.

In the process according to the invention, the underwater pipeline to be installed is leveled on the surface of the water, where it is supported by longitudinally spread floating elements that are fixed horizontally along the underwater pipelines. The underwater pipeline descends to a water depth free from waves, in such a way that the longitudinally spread floating elements enable it to stand up. The underwater pipeline is straightened and submerged along the direction of installation by releasing adjacent floating elements, whose release follows one after the other.

The laying of underwater pipelines is greatly simplified due to the horizontal attached floating elements. However, the advantage of standing floating elements can be used when laying underwater pipelines. Due to the longitudinally expanded condition of the floating elements, the depth of immersion of these elements in a vertically standing position is greater than in a lying position, which makes available a simple means for submerging underwater pipelines in a water depth free from waves. If the underwater pipeline is laid in individual bundles of pipes or welding arcs, which are joined together only on the surface of the water, then welding on the surface is easily possible, without having to give up the advantage of the underwater pipeline, which is suspended at a depth of water where there is no the influence of waves, when the same is to be leveled along the installation direction.

In accordance with the development of the process in accordance with the invention, the underwater pipeline to be installed, before submerging it at a depth of water free from undulations, is connected at the surface of the water. Such a design is particularly suitable for installation directions that are not regular or otherwise have a complicated geometry.

According to another embodiment, the underwater pipeline to be installed is placed on the water in an already assembled state. Especially with transparent configurations and almost completely straight installation directions, installation in an already welded form represents a great simplification.

For the sake of advantage, the floating elements are each attached to the underwater pipeline with at least two fastening devices, and the installation of the floating elements is achieved by releasing all the fastening devices, up to one each time - which remains, which is not assigned to the respective floating element in the middle.

With at least two fastening devices, the longitudinally extended floating element can be securely placed on the underwater pipeline. By releasing all the devices for attaching each floating element up to one, which is not assigned in the middle, it is achieved that the floating elements stand up independently and thus allow the submersion of the underwater pipeline to a water depth free from undulations. With this type of construction, the immersion step at a water depth free from undulations is greatly simplified.

For simplified work, exactly two fastening devices are used.

The final release of the underwater pipeline from the upright floating elements can happen automatically, by releasing individual floating pipes in a time-constant sequence, whereby the time difference between the opening of individual adjacent floating elements is set so that the allowable voltage value of the underwater pipeline is not exceeded.

With this measure, it is achieved that the final process of submerging the underwater pipeline occurs as evenly as possible and that the load on the pipe is kept low.

It is also possible that the release of the underwater pipeline from the upright floating pipes occurs depending on the pressure of the water surrounding the submerging pipeline and which occurs due to its submergence, after the first floating elements have been separated from the underwater pipeline.

An underwater pipeline, which begins to submerge on the one hand, pulls the floating elements under water one after the other and thereby increases the pressure of the water surrounding the water pipes, which pressure is proportional (proportional) to the depth of the pipes. A uniform submersion process achieves an even increase in water pressure, which can be used as a controller for the release of floating elements.

In a device according to the invention for laying underwater pipelines for carrying out the procedure according to the invention, the floating elements are spread out lengthwise and can be connected lying down to the underwater pipeline to be installed, with at least one fastening device that is not assigned to the middle of the respective floating element, possibly turn around.

Around such a pivotable position, the longitudinally recumbent floating element is straightened when all attachment points up to the pivotable attachment device are released.

For the sake of advantages, a fastening device which can be rotated is provided at the end of the respective floating element. Such an arrangement ensures an optimal relationship between the different immersion depths in the horizontal and vertical state of the floating elements.

Simplifications are made for the rotatable fastening device provided by the pipe clamp.

For further simplification, the individual floating elements of the system of floating elements, on the underwater pipeline to be installed, are attached with two fastening devices each.

For the automatic release of the underwater pipeline from the floating elements, in accordance with the design, a release mechanism dependent on the water pressure can be provided. According to a further embodiment, automatic time control is provided for the release of floating elements.

The method according to the invention and the device according to the invention are explained by means of adjacent drawings 1 to 3, whereby

drawing 1 schematically shows an underwater pipeline which, with a system of floating elements

according to the invention, it floats on the surface of the water

drawing 2 schematically shows the underwater pipeline hanging on the floating elements of the system

of floating elements according to the invention, at a water depth free from the influence of waves

drawing 3 schematically shows an underwater pipeline that is submerged by a process according to the invention

The drawings show the underwater pipeline in different stages of submersion with the application of the procedure according to the invention and one embodiment of the device according to the invention. Here, the corresponding number 1 describes the underwater pipeline that is to be placed on the bottom of the water 2. The bottom of the water 2 is shown at a distance from the surface of the water 3, which distance is not true to scale.

Floating elements 4a, 4b, 4c, 4d keep the underwater pipeline 1 on the surface of the water 3.

Such floating elements can be, for example, pieces of pipe and be provided in any number desired. For the sake of simplicity in drawings 1 and 2, only four are shown. Pipe clamps 5 and ropes 7 are provided for fixing the floating elements on the underwater pipeline 1. The pipe clamps 5 are connected to the closing locks 6 on the floating elements 4a through the intermediate member 5a, which is connected to the pipe clamp in such a way that it can be turned. , 4b, 4c, 4d. The closing locks 6 are opened, for example, depending on the external water pressure or with the help of some other automatic mechanism. In the initial state, which is shown in drawing 1, individual floating elements are placed parallel to the pipeline 1 to be installed. For this purpose, the floating elements on the part opposite the pipe clamps 5 are connected to the rope 7 with the underwater pipeline 1. These ropes can, for example, be opened with the help of a break thread, a remote control or another automatic mechanism.

To carry out the procedure according to the invention, the underwater pipeline 1 is first placed on the surface of the water. On this occasion, it can either be pushed to the surface of the water in individual parts and then welded on the surface of the water, or placed as a whole on the surface of the water, whereby each piece will be welded to the water on the ground and then pushed to the surface of the water.

In this state, the underwater pipeline 1 will be supported by the lifting weight of the horizontally lying floating elements 4a, 4b, 4c, 4d, which are connected in parallel with the underwater pipeline 1. The situation is therefore created as shown in drawing 1. By parallel, firmly with the underwater by pipeline connected floating elements, the installation of the underwater pipeline is greatly simplified. The possibly necessary welding process can easily be carried out on the surface of the water.

In order to reduce the impact of waves on the underwater pipeline 1, the underwater pipeline 1 is sunk to a water depth free from the influence of waves. For this, the ropes 7 are released. The own weight of the underwater pipeline 1 pulls it down and thus straightens the floating elements 4a, 4b, 4c, 4d. Now it hangs only over the pipe clamps 5 on the vertically standing longitudinally spread floating elements. The greater depth of immersion of the vertically standing floating elements leads to the fact that the underwater pipeline 1 reaches a deeper bed. The situation is created as shown in drawing 2.

The underwater pipeline 1 can only be placed above the bottom of the water 2 with particular precision and without major influence of the disturbing effect of the waves along the direction of installation. If the closing locks 6 use locks that depend on pressure, then they must not be opened at that water depth.

The process of release from the floating elements 4a, 4b, 4c, 4d is shown in drawing 3. The form of execution with pressure-dependent closing locks 6 is described below.

At one end of the underwater pipeline 1, the connection with the floating elements, which is still working, is released. This can be done with the help of an automatic mechanism or manually with the help of a breakaway chain or a remote control. As a result, one part of the underwater pipeline 1 is now submerged deeper. Adjacent floating elements are dragged deeper under water, which leads to an increase in the surrounding water pressure.

If, due to the increasing depth of immersion, the water pressure on one lock 6 increases beyond the swelling value, then that lock is opened and the connection between it and the associated floating element in the underwater pipeline 1 is released. The situation is as shown in drawing 3 as snapshot.

The floating element 14 has already been released from the pipeline 1. On that side of the drawing, the underwater pipeline 1 is already submerged. The floating element 4a has also already been released from the underwater pipeline 1 and is currently being raised to the surface of the water 3. In the case of the floating element 4b, the water pressure at the location of the closing lock 6 is not yet sufficient to release it. The connection between the floating element 4b and the underwater pipeline 1 via the pipe clamp 5 still exists. As the underwater pipeline is still submerged, given that the floating element 4a has just been released, the floating element 4b with the closing lock 6 will continue to submerge, so that the closing lock 6 of that floating element 4b also opens.

In the case of floating elements 4c and 4d, the closing locks 6 are not yet deep enough below the surface of the water and, consequently, do not yet open. In this way, continuous immersion is achieved, when the underwater pipeline 1 slides to the bottom of the water 2.

Although water pressure-dependent closing locks can be used, individual floating elements 4a, 4b, 4c, 4d can also be released in a time-constant sequence. The time difference (time interval) between the release of two adjacent floating elements from the underwater pipeline 1 is determined in such a way as to predict one maximum voltage value that can be tolerated for the underwater pipeline, and which is calculated from the water depth and the sinking speed, in which time intervals some floating elements must be released. The automatic controller can perform time-constant release. And through this time-constant release of the adjacent floating elements, a uniform sliding movement of the underwater water pipe 1 to the bottom of the water 2 can be achieved, without the tension of the water pipe 1 becoming too great.

Claims (13)

1. Procedure for laying underwater pipelines with the following steps: Installation of underwater pipelines (1) that are to be laid on the surface of the water (3), whereby the underwater pipeline (1) is supported by longitudinally spread floating elements (4a, 4b, 4c, 4d), which, lying along the underwater pipeline ( 1), attached. Submerging the underwater pipeline (1) to a water depth free from the influence of waves, in such a way that the longitudinally spread floating elements (4a, 4b, 4c, 4d) are allowed to stand up, Sinking underwater pipelines (1) to the bottom of the water (2) by successively releasing adjacent floating elements. 2. The procedure for laying pipelines according to claim 1, characterized by the fact that the underwater pipeline (1) to be laid, before submersion to a water depth free from the influence of waves, is connected only on the surface (3) of the water. 3. Procedure for laying underwater pipelines, indicated by the fact that the underwater pipeline (1) to be installed is pushed onto the water in an already assembled state. 4. The method according to one of the claims 1 to 3, wherein the floating elements (4a, 4b, 4c, 4d) are fixed with at least two fastening devices (5, 7) on the underwater pipeline (1) and the floating elements are straightened ( 4a, 4b, 4c, 4d) by releasing all fastening devices (7) of each individual floating element, up to one (5) which is not assigned to the respective floating element in the middle. 5. The procedure for laying underwater pipelines according to claim 4, characterized in that exactly two fastening devices (5, 7) are used per floating element (4a, 4b, 4c, 4d). 6. The procedure for laying underwater pipelines according to claim 1 to 5, characterized by the fact that the final release of the underwater pipeline (1) from the upright floating elements follows automatically, by releasing the floating elements in a time-constant order, with the time difference between the release of those adjacent floating elements arranged in such a way that one permissible voltage value in the underwater water pipe (1) is not exceeded. 7. The method according to one of the claims 1 to 5, characterized in that the release of the underwater pipeline (1) from the upright floating elements (4a, 4b, 4c, 4d) follows depending on the water pressure surrounding the sinking pipeline, after the first the floating elements were separated from the underwater pipeline. 8. Device for laying an underwater pipeline for carrying out the procedure according to one of the claims 1 to 7 with one system of floating elements consisting of a large number of floating elements and fastening devices for connecting the floating elements with the underwater pipeline, indicated by the fact that the floating elements ( 4a, 4b, 4c, 4d) longitudinally spread and lying can be connected to the underwater pipeline to be installed, whereby at least one device for fixing (5, 7) one of each floating element, which is not in the middle referring to the individual floating element assigned, can be rotated. 9. Device for laying underwater pipelines according to claim 8, characterized in that the device for fixing which can be rotated (5) is provided at one end of the individual floating element (4a, 4b, 4c, 4d). 10. A device for laying underwater pipelines according to one of claims 8 and 9, characterized in that the rotatable fastening device (5) is a pipe clamp. 11. Device for laying underwater pipelines according to one of claims 8 to 10, characterized in that the system of floating elements is made in such a way that each floating element (4a, 4b, 4c, 4d) is attached to exactly two fastening devices (5, 7). 12. Device for laying underwater pipelines according to one of claims 8 to 12, characterized in that for the automatic release of underwater pipelines (1) from floating elements (4a to 4d), a release mechanism (6) dependent on water pressure is provided. 13. Device for laying underwater pipelines according to one of claims 8 to 11, characterized in that automatic time management is provided for the release of floating elements (4a to 4d).