Apparatus for forming a Pipe

Field of the Invention

The present invention relates to an apparatus for forming a pipe or a pipeline.

Background Art

Large diameter pipelines are known to be used for the efficient transfer of fluids such as water, oil and natural gas as well as slurries. The fluids are pumped at high pressures through the pipeline continuously regardless of external conditions. The pipelines may traverse land, or lie under land or water.

Irrespective of the environment, the laying of pipelines according to present methods presents some serious problems. According to present methods, pipe sections often up to 12 m length or larger are transported to the construction site and welded together end-to-end as the laying of a pipeline proceeds.

Transportation of large bore pipe sections is costly and time consuming due to low weight to volume ratio of pipe sections. The maximum load of a transporter truck will be dictated by volume of the pipe sections rather than their weight. This leads to transportation inefficiencies as the maximum weight load may be significantly higher than the maximum volume load. Indeed, the transportation of pipe sections is one of the major contributors to the overall cost of pipeline construction.

The welding of the end-to-end pipe sections is troublesome because before welding, the pipe sections must be prepared by bevelling both ends and the pipe joints must be carefully aligned, in preparation for welding. Such precision alignment requires the use of highly qualified tradesmen to ensure that there is no misalignment of the pipe sections. Further, qualified welders are required to weld the joints. The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Disclosure of the Invention

In accordance with the present invention, there is provided an apparatus for forming a pipe or a pipeline comprising a rolling unit for forming at least one workpiece and at least one means for connecting adjacent workpiece longitudinal edges.

The means for connecting adjacent workpiece longitudinal edges may be any method known in the art including the use of lock seams or welding. Preferably, the means is provided in the form of a longitudinal welding unit.

Preferably, the rolling unit and the at least one longitudinal welding unit are operable simultaneously.

Preferably, the apparatus comprises at least one transverse welding unit.

The welding units may be provided in the form of arc welding units, gas welding units, resistance welding units, solid state welding units, high frequency induction units and energy beam welding units and combinations thereof. Preferably, the welding units are provided in the form of laser welding units.

Where the apparatus comprises welding units, the laser welding units may comprise any laser source known in the art including CO2 and Nd:YAG lasers such as those available from Trumpf, Germany. Preferably, the rolling unit comprises a plurality of inner and outer forming elements. The forming elements are preferably provided in the form of rollers. The axes of rotation of the rollers are preferably substantially normal to the longitudinal direction of the pipeline. However, it will be appreciated that the axes of rotation of the rollers are not necessarily parallel to each other.

Each outer roller is preferably paired with a complimentary inner roller wherein at least a portion of each outer roller is concavo-concave in cross-section and at least a portion of each inner roller is convexo-convex in cross-section. A small gap may be provided between complementary pairs of rollers to facilitate the passage of a workpiece therebetween, thereby bending said workpiece.

The radii of curvature of the concavo portion of an outer roller and the radii of curvature of the convexo portion of the complementary inner roller are preferably substantially the same.

The radii of curvature of the concavo portion of all of the outer rollers may be substantially the same as each other or may change through the rolling unit. Similarly, the radii of curvature of the convexo portion of all of the inner rollers may be substantially the same as each other or may change through the rolling unit.

The outer rollers and the inner rollers are preferably operable by hydraulics. Advantageously, hydraulics enable the gap between each outer roller and its complimentary inner roller to be manually adjusted or to automatically adjust to compensate for changes in workpiece thicknesses.

The spatial location of the rollers within the rolling unit are preferably staggered. Advantageously, staggering the rollers permits the gradual bending of workpieces into the desired shape. Further, the staggering of the rollers permits the preparation of pipelines of varying diameters. It will be appreciated that the location of the rollers may be adjusted to account for changes in workpiece dimensions. For example, the rollers may be moved transversely to accommodate changes in workpieces dimensions.

Preferably, each roller is provided on a roller shaft supported by at least one bearing box.

The rollers may be prepared from any suitable material known in the art including oil-hardened tool steel (L6), high-carbon high-chrome-alloy steel (D2), high-speed steel (M4) or carbide. The rollers may be proved with a resilient coating such as high-density polyurethane-elastomer.

It will be appreciated that the dimensions of the rollers will be influenced by the size of the apparatus and the workpieces, although it is anticipated that they may be approximately 400 mm in diameter and about 400 mm wide.

The apparatus may further comprise a feeding unit adapted to feed workpieces into the rolling unit. In one form of the invention, the feeding unit comprise an upper surface and a lower surface, adapted to feed two workpieces into the rolling unit. In one form of the invention, the upper surface comprises a plurality of rollers and the lower surface comprises a plurality of rollers.

The apparatus may further comprise an elevation unit adapted to feed workpieces into the feeding unit. Preferably, the elevation unit comprises a surface, operable at an upper height and a lower height. The upper height and the lower height are preferably, at substantially the same height as the upper surface of the feeding unit and the lower surface of the feeding unit respectively. The height of the surface of the elevation unit may be adjusted between the upper height and the lower height by any means known in the art including hydraulics. Preferably, the surface of the elevation unit comprises a plurality of rollers.

The apparatus may further comprise a stockpile for storage of workpieces. The stockpile may be provided with means to transfer the workpieces to the elevation unit. In one form of the invention, the means to transfer the workpieces to the elevation unit is a gantry equipped with an electromagnet.

The apparatus may further be provided with means for workpiece edge preparation prior to forming and/or welding and for x-ray inspection of all welds.

The apparatus may further be provided with means for inspection and testing of the pipeline by internally or externally disposed devices.

In accordance with the present invention, there is provided a method for the formation of a pipe or a pipeline, the method comprising the steps of:

feeding at least one workpiece into a rolling unit;

bending at least a portion of the at least one workpiece in the rolling unit; and

connecting adjacent workpiece longitudinal edges to form a pipe or a pipeline.

Preferably, the workpieces are substantially flat sheets. Preferably, the substantially flat sheets are quadrilateral.

In one form of the invention, the step of:

connecting adjacent workpiece longitudinal edges to form a pipe or a pipeline,

comprises longitudinally connecting one workpiece to itself to form a pipe or a pipeline.

In a second form of the invention, the step of:

connecting adjacent workpiece longitudinal edges to form a pipe or a pipeline, comprises longitudinally connecting a first workpiece to a second workpiece to form a pipe or a pipeline.

In one form of the invention, the step of:

connecting adjacent workpiece longitudinal edges to form a pipe or a pipeline,

comprises welding adjacent workpiece longitudinal edges to form a pipe or a pipeline.

Preferably, the steps of:

feeding at least one workpiece into a rolling unit;

bending at least a portion of the at least one workpiece in the rolling unit; and

welding adjacent workpiece longitudinal edges to form a pipe or a pipeline.

are performed substantially simultaneously on either the same workpiece or different workpieces.

In one form of the invention, the step of

feeding at least one workpiece into a rolling unit;

comprises feeding two workpieces into the rolling unit.

Where the method comprises the step of:

feeding two workpieces into the rolling unit

the step of: bending at least a portion of the at least one workpiece in the rolling unit;

preferably comprises bending a portion of each workpiece into a substantially semicircular pipe section.

In a second form of the invention, the step of

feeding at least one workpiece into a rolling unit;

comprises feeding one workpiece into the rolling unit.

Where the method comprises the step of:

feeding one workpiece into the rolling unit

the step of:

bending at least a portion of the at least one workpiece in the rolling unit;

preferably comprises bending a portion of the workpiece into a substantially circular pipe section.

In one form of the invention, the step of:

welding adjacent workpiece longitudinal edges to form a pipe or a pipeline.

comprises the steps of:

longitudinally welding a first semicircular pipe section to a second semicircular pipe section to form a substantially circular pipe section.

In one form of the invention, the step of:

welding adjacent workpiece longitudinal edges to form a pipe or a pipeline. comprises the steps of:

longitudinally welding a first substantially circular pipe section.

Preferably, the method comprises the further step of:

transversely welding the at least one workpiece to a further at least one workpiece.

In one form of the invention, the step of:

transversely welding the at least one workpiece to a further at least one workpiece,

comprises the steps of:

transversely welding a first workpiece to a further workpiece to increase the length of the first workpiece; and

transversely welding a second workpiece to a second further workpiece to increase the length of the second workpiece.

In one form of the invention, the step of:

transversely welding the at least one workpiece to a further at least one workpiece,

comprises the steps of:

transversely welding one first workpiece to a further workpiece to increase the length of the workpiece.

It will be appreciated from the foregoing discussion that pipes may be prepared in accordance with the present invention by forming either one sheet or two sheets into a pipe. Prior to the step of:

welding adjacent workpiece longitudinal edges to form a pipe or a pipeline,

the leading edges of the at least one workpiece are preferably treated to provide appropriate welding surfaces.

Prior to the step of:

transversely welding the at least one workpiece to a further at least one workpiece,

the leading edges of the at least one workpiece are preferably treated to provide appropriate welding surfaces.

Said treatment may comprise skimming off a portion of the material from the leading edges to provide clean and preferably square surfaces.

It will be appreciated that the steps of:

transversely welding the at least one workpiece to a further at least one workpiece; and

welding adjacent workpiece longitudinal edges to form a pipe or a pipeline,

may be performed simultaneously.

Alternatively, the steps of:

transversely welding the at least one workpiece to a further at least one workpiece; and

welding adjacent workpiece longitudinal edges to form a pipe or a pipeline,

may be performed at different times and at different locations. In this way, it may be possible to prepare pipe sections by bending workpieces and longitudinally welding said workpieces at a first location and transporting them to a second location for transverse welding and transformation into a pipeline. It will be appreciated that the term transverse welding will encompass the circumferential welding of half-pipes.

Preferably, after the step of

welding adjacent workpiece longitudinal edges to form a pipe or a pipeline,

the rolling unit and the pipeline move relative to each other to facilitate the formation of further pipeline.

Advantageously, repetition of the process permits the continuous production of pipeline.

Preferably, the rolling unit moves relative to the pipeline.

The present invention provides a system for forming and laying pipe from a movable vessel, vehicle, or other movable supporting structure. Instead of joining individual lengths or joints of pipe together end-to-end, as is done in substantially all existing systems, pipeline forming method permits the forming and laying of pipeline in a single continuous operation.

Preferably, prior to the step of:

transversely welding the at least one workpiece to a further at least one workpiece;

the workpieces are retained in place.

Preferably, prior to the step of:

welding adjacent workpiece longitudinal edges to form a pipe or a pipeline. the workpieces are retained in place.

In one form of the invnetion, the workpieces are held in place by retaining rollers.

It will be appreciated that the welding may create beads on the workpieces. It will further be appreciated that said beading may impact on the passage of workpieces through the rolling unit. Advantageously, the use of hydraulics on the rollers permits adjustment of the gap between complimentary rollers to accommodate the transverse beading when workpieces pass through the rolling unit.

Where desired, it will be appreciated that the beading may be removed by any means known in the art prior to the workpieces passing into the rolling unit.

The workpieces may be welded by any method known in the art including arc welding, gas welding, resistance welding solid state welding and energy beam welding. Preferably, the work pieces are welded by laser welding. Advantageously, laser beam welding employs a highly focused laser beam and has a very high energy density, making deep weld penetration possible and minimizing the size of the weld area. The process is significantly faster than arc welding and results in smaller weld beads.

Brief Description of the Drawings

The present invention will now be described, by way of example only, with reference to one embodiment thereof, and the accompanying drawings, in which:-

Figures 1a to 1e are elevated perspective views of a pipeline forming apparatus in accordance with an embodiment of the present invention depicting the apparatus in use;

Figure 2 is an elevated perspective view of a portion of the pipeline forming apparatus of Figure 1a to 1e; Figure 3 is an elevated perspective view of a portion of the pipeline forming apparatus of Figure 1a to 1e;

Figure 4 is an elevated perspective view of a portion of the pipeline forming apparatus of Figure 1a to 1e; and

Figure 5 is an internal view of a portion of the pipeline forming apparatus of

Figure 1a to 1e.

Best Mode(s) for Carrying Out the Invention

The pipeline forming apparatus of the present invention will now be described, by way of example only, with reference to one embodiment thereof.

In Figures 1 to 5 there is shown a pipeline forming apparatus 10 for the continuous formation of a pipeline comprising a rolling unit 12 and two longitudinal welding units 14. The present embodiment of the pipeline forming apparatus 10 further comprises two transverse welding units 16, a feeding unit 18, an elevation unit 20 and a stockpile 22.

The rolling unit 12 comprises a plurality of outer rollers 24 and inner rollers 26. Each outer roller 24 is paired with a complimentary inner roller 26 wherein at least a portion of each outer roller 24 is concavo-concave in cross-section and at least a portion of each inner roller 26 is convexo-convex in cross-section. A small gap is provided between complementary pairs of rollers.

The radii of curvature of the concavo portion 30 of all of the outer rollers 24 is substantially the same as each other. Similarly, the radii of curvature of the convexo portion 32 of all of the inner rollers 26 is substantially the same as each other. Further, the radii of curvature of the concavo portion 30 of each outer roller 24 and the radii of curvature of the convexo portion 32 of the complementary inner roller 26 is substantially the same. As shown in Figures 4 and 5, the spatial location of the rollers within the rolling unit are staggered to facilitate the gradual forming of a workpiece as it passes through the rolling unit.

The transverse welding units 16 are provided in the form of laser beam welding units and comprise clamps 34 for retaining workpieces during welding. An upper welding unit 36 and a lower welding unit (not shown) are provided.

The longitudinal welding units 14 are provided in the form of laser beam welding units and comprise retaining rollers 38 for retaining adjacent workpieces during welding.

A longitudinal welding unit 40 is provided on each side of the rolling unit 12.

The feeding unit 18 comprises two sets of rollers, an upper set 42 and a lower set 44, adapted to feed an upper workpiece 46 and a lower workpiece 48 to the rolling unit 12 respectively.

The elevation unit 20 comprises a platform 50 on hydraulic supports 52 adapted to retain the platform at a variety of heights.

The stockpile 22 comprises a gantry 54 adapted to transfer stockpiled workpieces 56 from the stockpile 22 to the elevation unit 20. The gantry 54 is provided with an electromagnet 55 to facilitate the transfer of the steel workpieces.

The apparatus 10 further comprises at least one laydown unit (not shown) to facilitate the laying of the formed pipeline onto the ground or onto pipeline supports (not shown).

The rolling unit 12, the feeding unit 18, the elevation unit 20, the stockpile 22, the gantry 54 and the laydown units are all movable with respect to the ground and in the embodiment described, are provided on tracks. The elevation unit 20 is mounted on a first platform 62 which is movable together relative to the ground and the rolling unit 12 and the feeding unit 18 are mounted on a second platform 64 which is movable relative to the first platform 62. The second platform 64 may be moveable relative to the first platform 62 by way of tracks or skids or the like.

The first platform 62 comprises tracks 66, the stockpile 22 comprises tracks 68, the gantry 54 comprises tracks 70 and the laydown units comprise tracks to facilitate movement over the ground.

The workpieces may be provided as medium-strength structural-steel plate with minimum yield strength of 290MPa. To prepare a pipeline of 1.8 m diameter, the workpieces should be 2827 mm wide. However, the roll forming process of the present invention stretches the material and a width of less than 2827 mm will be required. It will be appreciated that the design of the rolling unit will influence the degree of stretching.

In use, the gantry 54 picks up a first workpiece 74 from the stockpile 22 (Figure 1a) and moves from the stockpile 22 to the elevation unit 20 and lowers the first workpiece 74 onto the platform 50 which is in the lower position (Figure 1 b).

As the gantry 54 returns to the stockpile 22, the first workpiece 74 is transferred by way of powered rollers 76 from the platform 50 to the lower level of the feeding unit 18 (Figure 1c).

The gantry 54 picks up a second workpiece 78 from the stockpile 22 and moves from the stockpile 22 to the elevation unit 20 and lowers the second workpiece 78 onto the platform 58 which is in the upper position (Figure 1c).

As the gantry 54 returns to the stockpile 22, the second workpiece 78 is transferred by way of powered rollers from the platform 50 to the upper level of the feeding unit 18 (Figure 1d).

The gantry 54 returns to the stockpile to repeat the entire process. The first workpiece 74 is clamped in the clamping unit 34 such that its leading edge 80 is adjacent the trailing edge 82 of a workpiece 84 extending from the rolling unit 12 (Figure 1f).

The second workpiece 78 is simultaneously clamped in the clamping unit such that its leading edge 88 is adjacent the trailing edge of a workpiece 90 extending from the rolling unit 12 (Figure 1f).

The first workpiece 74 and the workpiece 84 are laser welded to each other and the second workpiece 78 and the workpiece 90 are simultaneously laser welded to each other. The upper welding unit 36 is provided above the junction between the first workpiece 74 and the workpiece 84. A lower welding unit (not shown) is provided below the junction between the second workpiece 78 and the workpiece 90.

Platform 64 moves over platform 62 in the direction of the stockpile 22. Said movement results in movement of the rolling unit 12 relative to the workpieces which in effect results in the workpieces 74 and 78 passing into the rolling unit 12. It will be appreciated that at this time at least a portion of each of the workpieces 84 and 90 have already passed into and out of the rolling unit 12.

As the workpieces 74 and 78 pass into the rolling unit 12, they are gradually formed into half pipes by the action of the staggered outer 24 and inner 26 rollers. As the leading portions of the workpieces form half pipes, adjacent half pipes are welded together with longitudinal laser welding units 14. It will be appreciated that in the embodiment described, two half pipes are welded together with two laser units on opposed sides of the rolling unit 12. The first laser unit 40 is clearly seen in Figure 3 and both laser units are visible in Figure 5.

The welding of the half pipes together occurs simultaneously with the movement of the platform. Whilst the speed of the second platform 64 relative to the first platform 62 and the speed of the laser units 14 relative to the pipeline are independent, the relevant power units are in communication so that the speed of the second platform 64 will be influenced and controlled by the speed of the laser unit 14 and the speed of the laser unit 14 will be influenced and controlled by the speed of the second platform 64. It will be appreciated that the speed of the laser unit 14 will be influenced by other factors including the integrity of the weld and the need to reweld any portions of pipeline.

During operation, the tracks 66, 68 and 70 may be continuously moving. Said movement results in movement of platform 62 relative to platform 64 and results in extrusion of pipeline 92 from the rear of the rolling unit 12.

It will be appreciated that longitudinal welding unit 14 can move independently of platforms 70 and 72 to control welding and that the scope of movement will be limited by the spatial arrangements of the retaining rollers 38.