Description :: Our patents

The guessed invention falls into field of main pipelines making and can be used for running of pipelines under water.

It is known, that now actual problem is making pipelines under water. The recent discovery of oil and gas deposits in most of cases are happened on marine shelf, and consequently was required prompt and inexpensive, in comparison with oil ships, transporting of these products on land,.

Besides, usage of sea bottom as a location of pipelines, allows making them practically rectilinear because of hindrances absence - mountains, settlements, roads and etc., without equalizers of longitudinal travel, as temperature on sea bottom is fixed at any time of year.

The installation for pipelines welding under water is known [1]. The installation includes half plunged pipelaying ship, units of tubes installation (cranes), welding machine - laser with optical devices, device of pipeline departure in water - stinger. The manufacture and packing of the pipeline is yielded by S-shaped technique [2].

The installation operates as follows. The tube, intended for a welding, with the help of cranes is erected in a level attitude in special units and one of its ends is docked and centered with pipeline end. With the help of welding machine, having a laser, is carried out tube welding to pipeline end. After process of welding pipelaying ship moves forwards on length of one tube. Thus pipeline end moves along units of tube installation up to welding spot. Simultaneously a part of pipeline is placed on bottom. After pipeline end will be placed in welding spot, following tube is erected on free units and further is carried out its welding to pipeline end. After that the work cycle of pipeline running is iterated.

A disadvantage of above-stated installation is, that during pipeline making is carried out its bend in two places – on sea surface, immediately after pipelaying ship, and near ocean bottom, that can give flaws in welds, and therefore, danger of pipeline breaking.

Other disadvantage of S-shaped technique of pipeline making is horizontal arrangement of welded tubes, and therefore, vertical weld run. Conditions of weld forming during welding permanently will vary because of its permanently varying attitude. Therefore, weld mechanical characteristics will vary also on its trajectory, that also has an effect on operating performances of builded pipeline.

The installation for laser welding of pipelines is known [3]. In it is used a box of beam guides, on which are horizontally disposed tubes, intended for a welding. A disadvantage of given installation is horizontal pipe arrangement, that demands, for welding process realization, a necessity of insert in installation composition added device of welded tube contraction to pipeline end.

Other disadvantage is, that for an exception of tube slightest sags in box under self weight is needed its fixing in many places on its length. An absence of tube sags is necessary because, it is mechanically bound to a beam guide and tube sags availability will give beam guide bending, and as laser beam is spread rectilinearly, an outage of beam guide units is possible.

The installation, operating J-shaped technique of pipeline running on sea bottom, is known [2], at which one during manufacture and packing on bottom the pipeline is curvated only once. At this technique on a pipelaying ship tubes are welded and lowered in water with a vertical technique. Circular weld will be in a horizontal plane and conditions of seam forming will be invariable. Accordingly mechanical characteristics of a seam will remain stationary on all its trajectory.

The tube, intended for a welding, is erected in vertical standing on pipeline end. With the help of welding machine circular weld is carried out. After that pipelaying ship moves forwards along future pipeline track. The pipeline end moves down to welding spot. Further with the help of a crane is taken following tube, it is erected in a vertical standing, delivered and erected on pipeline end. After this operation the work cycle of pipeline building with J-shaped technique is iterated.

The installation for sea line building with J-shaped technique is most close analog and consequently is selected as a prototype.

A disadvantage of above described technique of pipeline building is its low efficiency, resulting from a major part of added time. After next tube welding it is necessary to take with the help of a crane a new tube from storing place, to place it in a vertical standing, to transmit to the pipeline, to place on its end and, only after that, to yield its welding to pipeline end.

A problem, solved by the invention, is lowering of added time part in work cycle and, thereby raising pipeline building productivity.

The above-stated problem is solved by that the complex for pipelines running under water includes half plunged pipelaying ship, mounting crane, welding machine. Welding machine comprises a laser and a stinger of pipeline end departure. It is arranged inside pipeline vertical end, immediately near to its end, the complex has the box with tubes, disposed vertically in it.

The welding machine has positive buoyancy, and distance from water level in the pipeline up to welded junction is equal to a distance from water level in the pipeline up to a horizontal axis of laser beam. The welding machine can have also self drive unit of transposition on pipeline interior surface.

The technological laser of welding machine is stationary and is arranged above of tubes box, and on a water surface inside the pipeline floats the welding head. The floating welding machine (including the laser) or floating welding head (in it the laser does not enter, it is disposed separately from a welding head) have self drive unit of transposition on pipeline interior surface or mechanism of fixing, including clamp.

During pipeline building the attitude of welding machine or welding head concerning the pipelaying ship remains invariable.

The complex looks like this (fig. 1). On half plunged pipelaying ship 1 dispose mounting crane 2, box 3 of tubes 4, intended for a welding. The welding machine 5, incorporating the laser (on fig. 1 is not shown), is arranged inside the pipeline, near to its end.

In variant the welding machine can represent separately disposed laser 6 and welding head 7 (fig. 5). Besides the complex contains a stinger 8 – a device for pipeline end departure. In that case, when the welding machine (welding head) has negative buoyancy, it has self drive unit of transposition 9 (figs. 2, 3) and also independent power supply 10. In that case, when the welding machine (welding head) has positive buoyancy, it has clamps 11, fixing the welding machine or head concerning welding junction 12.

The welding machine and welding head have the data unit of junction location 13.

The welding machine and welding head have a drive unit of vertical displacement 14 of focusing lens 15 and rotary mirrors 16, and also drive unit of their rotating in a horizontal plane 1. Box of tubes (see also fig. 4), intended for a welding to pipeline has self rotation drive 18. The pipeline end 19 is anchored in holders 20. The complex operation is drived with control system (is not shown).

The complex operates as follows. By command of control system, arranged on pipelaying ship 1, mounting crane 2 erects vertical tubes 4 in box 3. The rotation drive 18 ensures a lead of necessary box seat to tubes installation place. After installation of all tubes in the box, rotation drive brings the tube, intended for a welding, to the end of pipeline 19, anchored in holders 20. Thus the gap between welded tube end and pipeline end is minimum. In that case, if because of technological reasons is necessary the absence of a gap between welded tube and pipeline end, by command of control system the clamp of a tube in box seat is attenuated and it under self weight slides down to touch with pipeline end. The tube and pipeline axes are coincide. In case the laser is disposed in welding machine, a radiation, generated by the laser is guided on rotary mirror 16, being reflected from which falls on focusing lens 15. In focusing lens the radiation is focused and is guided on welded junction 12. The rotation drive 17 ensures a welding of circular weld. In case the laser 6 is disposed above a welded tube (fig. 5), the radiation, generated by it, is guided vertically downwards inside welded tube to welding head 7, where falls on rotary mirror and futher through focusing lens on welded junction.

After welding a circular weld, pipelaying ship 1 moves forwards along future pipeline track. Thus pipeline end together with welded tube move downwards on holders 20 and stinger 8. In that case, if specific gravity of welding machine (or welding head) is more than water specific gravity, welding machine (or the head) moves along pipeline lowering end with the help of self drive unit 9. And summary transposition of welding machine (or the head) and pipeline end is equal to zero point.

In that case, if welding machine or (in variant) welding head has positive buoyancy, welding machine or head is in floating state inside the pipeline and mounts together with water level concerning pipeline end. Concerning the ship welding machine (welding head) is immobile at this time. As distance from water level in the pipeline up to welded junction is equal to distance from water level up to laser beam horizontal axis (size A on fig. 2), focusing lens automatically will be placed opposite welded junction.

The pipeline in any case is filled with marine water for holding hydrostatic tests (see [2], page 53). The transposition of welding machine or head happens until that moment, when will work junction position sensor 13. The working clamps 11 hardly anchor welding machine or head concerning the pipeline. After that drive unit of vertical displacement 14 lowers focusing lens 15 and rotary mirror 16 downwards, lower than pipeline end level with the purpose of unobstructed lead of new tube. After that the rotation drive of the box brings the tube, intended for welding, to pipeline end and all technological process is iterated. During laser welding mounting crane 2 erects in free box seat a new tube. The continuity of pipeline building technological process and its high efficiency is ensured. The electric power supply of all systems of welding machine or welding head is ensured with independent power supply (storage cell) 10. After welding of all pipeline tubes directly ahead of beach is maximum lowered the last welded tube, and welding machine or welding head are extracted from the pipeline.

What is claimed is:

A complex for underwater pipelines running, comprising half plunged pipelaying ship, mounting crane, welding machine, characterised in that welding machine contains the laser, laser welding head, including rotary mirror and focusing lens, and laser welding machine or even only its part – welding head - are fulfilled as floating, inside vertical pipeline end with an opportunity of its orientation concerning pipeline end.
The complex according to claim 1, wherein the laser and welding head are separate constructions of welding machine, and the laser is arranged on pipelaying ship, and floating welding head is supplied with independent power supply and is installed in a housing with clamps.