NL2007441C2

NL2007441C2 - Coating device for coating a pipeline or a pipe section.

Info

Publication number: NL2007441C2
Application number: NL2007441A
Authority: NL
Inventors: Robert Louis Hoften
Original assignee: Heerema Marine Contractors Nl
Priority date: 2011-09-19
Filing date: 2011-09-19
Publication date: 2013-03-21

Description

P30754NL00/WHA

Title: Coating device for coating a pipeline or a pipe section

Field of the invention

The present invention relates to a coating device for coating a pipeline or a pipe section. The present invention further relates to a method of coating a pipe or pipeline and to a pipeline laying vessel comprising the coating device. Coating devices are known per 5 se.

Description of the prior art

During pipelay operations in a maritime environment, pipe sections are connected one by one to a pipeline which is suspended from a vessel. Generally, the connections are 10 performed by welding the pipe sections end-to-end to the pipeline. Both the end of the pipeline and the end of the pipe section are generally provided as bare metal in order to achieve a good quality of the weld. After the pipe section has been welded to the pipeline, it is necessary to provide a protective coating layer around the zone of bare metal near the weld to protect the metal of the formed pipeline. This zone is generally referred to as the 15 field joint. This is generally done in a coating operation. This coating process is generally referred to as field joint coating (FJC), because it relates to the coating of a joint which is made in the field, as opposed to the coating process of the rest of the pipe, which is normally carried out on shore.

The distance over which the pipe section is to be coated in the FJC process may lie 20 in the order of 1-2m. A greater distance may also be possible.

Prior to the coating of the pipe section, the pipe section itself is generally pre-heated. The pre-heating allows the subsequent coating material to become attached to the pipe section. The coating material which contacts the pipe section generally melts and forms a connection with the pipeline.

25 In the prior art, a coating device is provided which provides the metal with a coating.

Generally, multiple layers are provided for a complete coating. Often, an epoxy layer is provided on the bare, pre heated metal as an anti-corrosion coating. Subsequently, an adhesive is provided to ensure proper adhesion between the epoxy and further coating layers. The further coating layers may serve as mechanical protection or thermal insulation. 30 In the coating device according to the prior art, it is customary to apply the anti corrosion coating to the field joint in a first operation, and to subsequently apply the -2 - adhesive on the same area of the pipeline. Generally, the coating device comprises a frame in which spray nozzles are provided for both the adhesive layer and the coating layer.

The frame is a tubular frame or a substantially tubular frame which has a through opening through which in use the pipeline extends. In the coating device of the prior art, a 5 first set of nozzles for the adhesive layer is provided and a second set of nozzles for the protective layer is provided. The first set and the second set are spaced apart in the axial direction of the pipeline, i.e. in the direction of the through hole.

In operation, a protective layer is first applied around the pipe over a certain length of the pipe. This is approximately the length of the field joint, however some overlap with the 10 onshore applied coating will occur in order to ensure that all bare metal is covered. During the spraying, the coating device is moved in an axial direction. The length of pipe which is sprayed corresponds substantially to the axial distance travelled by the coating device.

Between the spraying of the protective and the adhesive layer, the coating device is shifted in the axial direction, such that the nozzles of the adhesive layer are positioned in 15 the axial position where the nozzles of the protective layer were during the first spraying run. Next, the adhesive layer is sprayed onto the pipeline. A same or similar back and/or forth movement in the axial direction is made during the spraying of the adhesive layer.

It was found that the coating device of the prior art has a number of drawbacks.

20 Summary of the invention

The invention provides a coating device constructed for coating a pipe section, the coating device comprising at least: a first set of nozzles configured for spraying a first coating material onto the pipeline, and 25 - a second set of nozzles configured for spraying a second, different coating material onto the pipeline, the coating device being constructed to make a rotary movement about the pipe section during the spraying of the first and second coating material.

In an embodiment, the coating device is constructed to, when in use, maintain 30 substantially stationary along an imaginary firing line which in use corresponds to the pipe axis.

In an embodiment, the nozzles of the first set are positioned in a first circular sector about the firing line, and the nozzles of the second set are positioned in a second, different circular sector about the firing line.

35 The first and second circular sector are spaced apart about the circumference of the pipeline.

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In an embodiment, the first set of nozzles extends along a substantially same section of a firing line as the second set of nozzles.

In an embodiment, the nozzles of the first set are oriented to spray in a different direction than the nozzles of the second set.

5 In an embodiment, the first set of nozzles and the second set of nozzles are placed substantially on opposite sides of the firing line.

In an embodiment, the nozzles of the first set of nozzles define a first spray area and the nozzles of the second set of nozzles define a second spray area, wherein the first spray area and the second spray area are located at a distance from one another.

10 In an embodiment, the coating device comprises a frame to which the first and second set of nozzles are mounted, the frame being rotatable around the firing line in order to allow coating of the entire circumference of the pipeline by both the first set of nozzles and the second set of nozzles.

In an embodiment, the first set of nozzles is arranged at a fixed distance from the 15 second set of nozzles.

In an embodiment, the coating device comprises rollers or skidding members which are mounted to the frame and via which the coating device is rotatably supported about the firing line.

In an embodiment, the first set of nozzles and the second set of nozzles are 20 rotatable about the firing line over an angle of at least 180 degrees.

In an embodiment, the first set of nozzles and the second set of nozzles are rotatable over an angle of at most 270 degrees about the firing line.

In an embodiment, the first set of nozzles is mounted to a first frame and the second set of nozzles is mounted to a second frame which is independently rotatable about the 25 firing line from the first frame, allowing a distance between the first circular sector and the second circular sector to be varied.

In an embodiment, the first set of nozzles is configured to spray a fusion bonded epoxy (FBE) coating.

In an embodiment, the second set of nozzles is configured to spray an adhesive, in 30 particular a polypropylene adhesive. More particularly, the second set of nozzles is connected to a reservoir of chemically modified polypropylene (CMPP).

In an embodiment, the coating device comprises a drive constructed to rotate the nozzles about said pipeline.

In an embodiment: -4- - the first set of nozzles extends over a certain distance in the direction of the firing line, such that the first set of nozzles is configured to apply a coating over said distance, and - the second set of nozzles extends over a certain distance in the direction of 5 the firing line, such that the second set of nozzles is configured to apply a coating over said distance.

Generally, the distance for the first set of nozzles will be substantially the same as the distance for the second set of nozzles.

In an embodiment, the first set of nozzles defines an elongate spraying area which 10 extends in the direction of the firing line, and the second set of nozzles defines an elongate spraying area which extends in the direction of the firing line

In an embodiment, the coating device comprises a rotary frame, wherein the first set of nozzles and the second set of nozzles are connected to said rotary frame.

The present invention further relates to a method of coating a pipeline, the method 15 comprising: - providing a pipeline or pipe section, and providing a coating device at the pipeline, the coating device comprising: o a first set of nozzles configured for spraying a first coating material onto the pipeline, and 20 o a second set of nozzles configured for spraying a second, different coating material onto the pipeline, the coating device being constructed to make a rotary movement about the pipe section during the spraying of the first and second coating material, and providing a first layer of coating material on said pipeline by spraying with the 25 first set of nozzles while rotating the coating device about the pipe section, and providing a second layer of coating material on said pipeline by spraying with the second set of nozzles while rotating the coating device about the pipe section.

30 In an embodiment, the method comprises: spraying with the first set of nozzles during a first time period - spraying with the second set of nozzles during a second, subsequent time period.

In an embodiment, the coating device is maintained substantially stationary in the 35 direction of the pipe axis during the spraying of the first and second coating materials.

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In an embodiment, the method comprises rotating said coating device over an angle during the first time period and rotating the coating device back over a same angle during the second time period.

In an embodiment, the method comprises spraying the first coating material over a 5 full 360 degrees circumference of the pipeline during a first time period and spraying the second coating material over substantially the same area during a second time period.

In an embodiment, the method comprises rotating said coating device over an angle of between 180-200 degrees during the first time period.

In an embodiment, the method comprises providing a first coating layer from said 10 first set of nozzles in first circular sector of the pipeline while at the same time providing a second coating layer from a second set of nozzles in a second circular sector of the pipeline.

15 Brief description of the figures

The previous and other features and advantages of the present invention will be more fully understood from the following detailed description of exemplary embodiments with reference to the attached drawings.

Figure 1A shows a sectional side view of a coating device according to the prior art.

20 Figure 1B shows a sectional side view of a coating device according to the prior art in operation.

Figure 2 shows a diagrammatic top view of a coating device according to the invention.

Figure 3 shows a perspective view of a coating device according to the invention.

25 Figure 4 shows a perspective view of another embodiment according to the invention.

Figure 5 shows a diagrammatic top view of another embodiment according to the invention.

Figure 6A shows a perspective view of a coating device according to the invention in 30 use, in an open position.

Figure 6B shows a perspective view of a coating device according to the invention in use, in a closed position. Like reference numerals denote like parts.

Detailed description of the figures 35 Turning to Figures 1A and 1B, a coating device 10 according to the prior art is shown. The coating device 10 comprises an upper set 12 of spray nozzles 14 and a lower -6- set 16 of spray nozzles 18. The upper set 12 is spaced apart from the lower set 14 in the axial direction, i.e. the upper set 12 is provided at a distance from the lower set 14 in the axial direction. The upper set 12 of spray nozzles 14 is configured to spray a corrosion protective coating on the pipe section or pipeline 20. The lower set 16 of spray nozzles 18 is 5 configured to spray an adhesive. This can also be the other way around.

The nozzles 14 are positioned all around the pipe 20 so that the full circumference of the pipe 20 can be provided with a protective coating layer.

In use, during the spraying of the protective coating, the coating device 10 is moved back and forth in the direction 24 of the pipe axis 22.

10 After the spraying of the protective coating layer, the coating device 10 is positioned such that the nozzles 18 are in the position where the nozzles 14 were before. Next, a layer of adhesive is sprayed onto the pipe 20 all around the circumference. The coating device 10 again is moved in the axial direction 24 during the spraying of the adhesive.

15 Turning to figure 1B, in the present invention it was recognized that a disadvantage of the device and method of the prior art is that the distance 8 (or height) which is required by the coating device 10 in operation can be significantly larger than the distance 9 (or height) of the field joint, since the two sets of nozzles 12,16 are spaced apart from each other along the firing line. This leads to an inefficient set up, requiring a lot of height in the 20 work station.

Turning to figures 2 and 3, a coating device 30 according to the invention is shown. The coating device 30 is formed by a tubular (or annular) frame 32 which defines a through hole 34. A firing line 36 is defined in the center of the through hole 34 and extends through the coating device 30. In use, the firing line 36 will coincide with the pipe axis. The coating 25 device 30 comprises an inner wall 33 and an outer wall 35. The coating device 30 has an upper end 60 and a lower end 61.

The coating device 30 is configured to be positioned on board a pipeline laying vessel. The coating device is in particular suitable to be positioned in a J-lay installation, in particular in a work station of a J-lay installation.

30 The coating device 30 has a length (or height) 38, an inner diameter 40 and an outer diameter 42.

The coating device comprises two halves 45A, 45B. The coating device 30 comprises hinges 44 on one side and locking members 46 on an opposite side. The two halves 45A, 45B are hingeably connected to one another via the hinges 44 and are 35 constructed to open in order to let the pipe 20 into the through hole 34. Subsequently, the two halves 45A, 45B are closed again and locked with the locking members 46.

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The halve 45A is provided with a first set 50 of spraying nozzles 51, and the halve 45B is provided with a second set 52 of spraying nozzles 53. The first set 50 and the second set 52 are located opposite one another. The first set 50 defines a first spray area 56 and the second set 52 defines a second spray area 57. Contrary to the prior art, the first 5 set 50 and the second set 52 are not spaced apart in the direction of the firing line, but extend along a substantially same section of the firing line.

A first reservoir is provided comprising the FBE coating. The first reservoir is connected to the first set 50 of nozzles 51 via a conduit 70, a pump and a manifold inside the frame 32. A second reservoir is provided comprising chemically modified polypropylene 10 (CMPP). The second reservoir is connected to the second set 52 of nozzles 53 via another conduit 72, pump and a manifold inside the frame 32.

A first circular sector 100 covered by the first set 50 of nozzles 51 may be greater or smaller than a second circular sector 101 covered by the second set 52 of nozzles 53.

A distance 71 is provided between the nozzles 51 and the nozzles 53 which are 15 closest to one another, see figure 3. The distance 71 also defines the distance between the first spray area 56 and the second spray area 57.

The first set 50 is provided along a circular sector 100 (when viewed in the direction of the firing line 36, i.e. in the top view of figure 2) of a little less than 180 degrees, i.e. 150 -179 degrees. The second set 52 is also provided along a second circular sector 101 of a 20 little less than 180 degrees, i.e. 150 -179 degrees. The first and second circular sector are spaced apart over a certain angle. This angle is between 1 and 30 degrees in the embodiment of figures 2-3. The spray areas 56, 57 also cover a circular sector of between 150 and 180 degrees.

The first set 50 and the second set 52 are provided along the entire length 38 of 25 the inner wall 33. A total number of 150 nozzles 51 may be provided as a grid of 15 nozzles 51 in the axial direction 36 by 10 nozzles in a circumferential direction 37. The same configuration of 15 by 10 may be used for the second set 52 of nozzles 53. A different number of nozzles of course is also possible.

When viewed in the direction of the firing line 36, the first spray area 56 and the 30 second spray area 57 do not overlap. However, embodiments are conceivable wherein the first spray area 56 and the second spray area 57 partially or wholly overlap one another.

Fusion bonded epoxy coating, also known as fusion-bond epoxy powder coating and commonly referred to as FBE coating, is an epoxy based powder coating that is widely used to protect steel pipe used in pipeline construction from corrosion. FBE coatings are 35 thermoset polymer coatings. The name 'fusion-bond epoxy' is due to resin cross-linking and the application method, which is different from a conventional paint.

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The frame is supported on the work station floor via rollers 76 mounted to the underside of the frame 32. The rollers 76 are connected to a drive 77 which drives the rollers 76 in order to rotate the coating device 30. The rollers 76 may also be skidding members. The rollers 76 may be configured to run on a circular track 79 which extends 5 around the firing line. The track 79 may be arranged below the coating device 30, for instance on a floor 75 of the working station. The track 79 may also be arranged above the coating device, so that the coating device is suspended from the track.

Alternatively, the track and/or the frame may be supported by a manipulator arm. This may be beneficial when moving the coating device to or from the pipeline, as well as 10 provide an efficient support of the device, also when the pipeline is laid under an angle.

Figure 4 shows another embodiment of the coating device 30 according to the invention. The coating device has a substantial C-shape, when seen in top view. This embodiment does not have hinges to open the coating device, but the pipeline 20 may 15 enter through a permanent opening 80 in the side of the coating device 30. The circular sectors covered by the first set 50 and the second set 52 of nozzles are a little smaller than 180 degrees, i.e. for instance 130-150 degrees. This leaves an opening 80 of between 60 and 100 degrees.

Figure 5 shows another embodiment of the coating device 30 according to the 20 invention. A first frame 32A and a second frame 32B are provided which are independently movable relative to one another, i.e. the first frame 32A may have a different angular speed than the second frame 32B. This may be limited by the fact that the first frame 32A can not pass the second frame 32B. The first frame may extend about a circular sector of about 20-60 degrees, and the second frame may extend over a same circular sector.

25 The first circular sector 100 and the second circular sector 101 extend over an angle of approximately 45-50 degrees. The circular sectors 101, 102 are spaced apart over an angle 102 of 130-135 degrees, which angle may vary.

The first and second frame may be arranged as separate carts which roll over a circular track 49 which extends around the firing line.

30

Operation

Turning to figures 6A and 6B, in use, on board a pipeline laying vessel having a J-lay installation, a pipeline is laid with the J-lay installation. A new pipe section 110 is welded to a free end of the pipeline 112 which is suspended from the pipeline laying vessel. The 35 upper end 114 of the pipeline 112 and the bottom end 116 of the new pipe section which -9- form the weld zone 118 are bare metal, i.e. metal without any coating. The metal is generally steel. The metal must be bare in order to achieve a weld of high quality.

The upper 114 end of the pipeline and the lower end 116 of the new pipe section are welded end-to-end in the welding station.

5 Next, the newly formed pipeline is lowered in direction 117 until the weld zone 118 is inside the coating device 30, approximately half-way the height of the coating device 30. A pre-arranged coating section 120 on the pipeline 112 starts approximately at a lower end 61 of the coating device 30 and a pre-arranged coating section 120 on the pipe 110 section starts approximately at the upper end 60 of the coating device.

10 The inner diameter of the coating device 30 is greater than the outer diameter of the coating 120 of the pipeline 112 and pipe section 110.

It is also possible that the coating device 30 initially is in a position remote from the firing line 36, and only moved into place, i.e. around the pipe 20, when the weld connecting the pipeline and the pipe section is in the correct position, i.e. approximately halfway the 15 height 38 of the coating device 30.

It is also possible that welding and coating operations are performed in the same work station. In this situation the welding equipment is moved away from the pipe and the coating equipment is moved towards the pipe. It is also possible that the pipe is moved from the welding equipment towards the coating equipment in either a vertical or horizontal 20 manner.

The coating device 30 is positioned around the pipeline 20 as can be seen in figures 2 and 6. When the coating device is in the correct position, it is closed and the coating device 30 surrounds the pipe 20.

In a first spraying step, the first set 50 of nozzles 51 spray the FBE coating onto the 25 pipeline. As discussed above, generally a grid of n by m nozzles will be provided on each half 45A, 45B. The pipeline is coated from the outside.

In figures 6a and 6b, a floor 75 of the work station has not been shown, for clarity purposes.

The liquid FBE film wets and flows onto the surface on which it is applied, and soon 30 becomes a solid coating by chemical cross-linking, assisted by heat. This process is known as “fusion bonding”. The chemical cross-linking reaction taking place is irreversible. The coating is known as “thermoset” coating. During the spraying, the coating device 30 is rotated around the pipe 20 in the direction of arrow 58. The coating device 30 is stationary in the axial direction relative to the pipeline, i.e. the coating device only rotates relative to 35 the pipeline. Because the first set 50 and the second set 52 are interconnected via the - 10- frame, the first and second set always rotate at a same angular speed. The first spraying step lasts a first time period.

The coating device is rotated over an angle of a little more than 180 degrees, i.e. 185-200 degrees. During this rotation, the entire circumference of 360 degrees of the pipe 5 20 is sprayed over the entire height of the coating device 30. The nozzles 51 then stop spraying the FBE coating.

In a next step, the second set 52 of nozzles 53 is used to spray the adhesive onto the FBE coating. This step takes a second time period. An idle period may be provided between the first and second time period.

10 The first and second time period may have a same length, but may also have a different length.

During the second step, the coating device 30 is rotated in a reverse direction 59. The coating device 30 is rotated back over an angle of a little more than 180 degrees, i.e. 185-200 degrees. In the second step the coating device is also stationary in the axial 15 direction. After both spraying operations, the coating device 30 is back in the initial position. The coating device 30 is not moved in the axial direction of the pipe 20 during the spraying of the first and second coating material, but only rotated around the pipe 20. This adds to the simplicity of the coating operation.

The diameter of the pipe 20 may vary in use. This results in a varying spray distance 20 55 for the nozzles 51,53. In another embodiment, the position of the spray nozzles is adjustable in a direction towards and away from the firing line. This makes it possible to maintain a same spraying distance for different pipe diameters or to vary the spraying distance according to different operational conditions, such as applied coating material, temperature, etc.

25 In order to achieve a first layer of FBE coating and a second layer of adhesive having a uniform thickness, it is important that the coating device 30 is always rotated during the spraying and not stopped. Alternatively, to ensure an even layer thickness, the amount of sprayed material may be regulated via an (electric) controller of the rotating speed and spraying pressure.

30 The rotational speed during the first time period may be the same or differ from the rotational speed during the second time period.

The operation of the embodiment of figure 4 is substantially the same as the operation of the embodiments of figures 2-3, with a difference that the pipe enters the through hole 34 in a lateral direction through the opening 80 in the side of the coating 35 device 30. In practice, the pipe 20 is held still and the coating device 30 is moved laterally -11 - towards the pipe 20. The coating device 30 does not fully surround the pipe 20 but substantially surrounds the pipe 20.

The operation of the embodiment of figure 5 is substantially the same as the operation of the embodiment of figures 2-3. In use, there is more freedom of movement of 5 the two frames 32A and 32B.

It will be obvious to a person skilled in the art that the details and the arrangement of the parts may be varied over considerable range without departing from the spirit of the invention and the scope of the claims.

In particular, the present coating device may also be used with the firing line 36 in a 10 substantially horizontal orientation, for instance on an S-lay vessel. It is also possible to use the present coating device in a non-maritime environment, i.e. on land.

It is possible that the rotation of the coating device 30 is limited, for instance to a maximum of 270 degrees. This is enough to allow the coating device 30 operable to spray the entire circumference of 360 degrees.

15 Because the coating device does 30 not need to be moved axially during the coating operation, less height is required for a coating station than in the prior art. This results in a smaller piece of equipment which is an advantage in J-lay systems, where space in general and the available height in particular are generally limited.

Another advantage is that the spray area may be closed more easily than when the 20 coating device 30 needs to be moved axially. This results in a better quality of the coating.

Claims

A coating device constructed for coating a pipe part, the coating device comprising at least: - a first set of nozzles adapted to spray a first coating material onto the pipeline, and 5. a second set of nozzles which are arranged for spraying a second, different coating material onto the pipeline, wherein the coating device is constructed to make a rotating movement about the pipeline during the spraying of the first and second coating material.

A coating device according to claim 1, wherein the nozzles of the first set are positioned in a first circle sector around an imaginary firing line that in use corresponds to the axis of the pipe, and wherein the nozzles of the second set are positioned in a second , other circle sector around the firing line.

3. Coating device as claimed in claim 1 or 2, wherein the first set of nozzles extends along a substantially same part of a firing line as the second set of nozzles.

4. Coating device as claimed in any of the foregoing claims, wherein the nozzles of the first set are oriented to spray in a different direction than the nozzles of the second set.

5. Coating device as claimed in any of the foregoing claims, wherein the first set of nozzles and the second set of nozzles are placed substantially on opposite sides of the firing line.

6. Coating device as claimed in any of the foregoing claims, wherein the nozzles of the first set of nozzles define a first spray area and wherein the nozzles of the second set of nozzles define a second spray area and wherein the first spray area and the second spray area are at a distance are spaced apart in the circumferential direction of the pipeline.

7. Coating device as claimed in any of the foregoing claims, included a frame on which the first and second set of nozzles are mounted, the frame 35 being rotatable about the firing line in order to coat the entire circumference of the pipeline through both the first set of nozzles as well as the second set of nozzles.

8. Coating device as claimed in claim 7, wherein the first set of nozzles is arranged at a predetermined distance from the second set of nozzles.

Coating device according to one of the preceding claims, further comprising rollers or sliding parts mounted on the frame and via which the coating device is rotatably supported around the firing line. 10

A coating device according to any one of the preceding claims, wherein the first set of nozzles and / or the second set of nozzles are rotatable about the firing line through an angle of at least 180 degrees.

A coating device according to any one of the preceding claims, wherein the first set of nozzles and / or the second set of nozzles are rotatable through an angle of at least 270 degrees about the firing line.

12. Coating device as claimed in any of the foregoing claims, wherein the first set of nozzles is mounted on a first frame, and wherein the second set of nozzles is mounted on a second frame which is independently movable about the firing line with respect to the first frame , wherein a distance between the first circle sector and the second circle sector can be varied.

A coating device according to any one of the preceding claims, wherein the first set of nozzles is adapted to spray a fusion bonded epoxy (FBE) coating.

14. Coating device as claimed in any of the foregoing claims, wherein the second set of nozzles is adapted to spray an adhesive, in particular a polypropylene adhesive, more in particular a chemically modified polypropylene (CMPP) adhesive.

A coating device as claimed in any one of the preceding claims, comprising a drive adapted to rotate the nozzles around said pipeline. 35

16. Coating device according to one of the preceding claims, wherein: the first set of nozzles extends over a certain length in the direction of the firing line, such that the first set of nozzles is arranged to apply a coating over said coating length, and the second set of nozzles extends over a certain length in the direction of the firing line, such that the second set of nozzles is arranged to apply a coating over said length.

17. Coating device as claimed in any of the foregoing claims, wherein the first set of nozzles defines an elongated spray area that extends along the firing line, and wherein the second set of nozzles defines an elongated spray area that extends along the firing line.

18. Coating device as claimed in any of the foregoing claims, comprising a rotatable frame, wherein the first set of nozzles and the second set of nozzles are connected to said rotatable frame.

A vessel for laying pipelines, comprising the coating device according to any of the preceding claims.

A method of coating a pipeline, the method comprising: - providing a pipeline or pipe part, and - providing a coating device at the pipeline, the coating device comprising: o a first set of nozzles that are arranged for spraying a first coating material onto the pipeline, and o a second set of nozzles adapted to spray a second, different coating material onto the pipeline, the coating device being constructed to rotate around the pipeline during spraying of the first and second coating material, and - applying a first layer of coating material to said pipeline by spraying with the first set of nozzles while the coating device is being rotated around the pipe part, and - applying a second coating material layer of coating material on said pipeline 35 by spraying with the second set of nozzles while the coating insert direction is rotated around the pipe part. - 15-

A method according to claim 20, the method comprising: - spraying with the first set of nozzles during a first period of time, - spraying with the second set of nozzles during a second, subsequent period of time. 5

A method according to claim 20 or 21, wherein the coating device is held substantially stationary in the direction of the axis of the pipe during spraying of the first and second coating materials. 10

A method according to any of claims 20-22, comprising spraying the first coating material over a full 360 degrees in the circumferential device of the pipeline for a first period of time and spraying the second coating material over substantially the same area during a second period of time .

A method according to any of claims 20-23, comprising rotating said coating device through an angle of between 180-200 degrees during the first period of time.

A method according to any of claims 20-24, comprising rotating said coating device through an angle during the first time period and rotating the coating device back through a substantially same angle during the second time period.

A method according to any of claims 20-25, comprising providing a first coating layer from said first set of nozzles in the first circle sector of the pipeline while simultaneously applying a second coating layer from the second set of nozzles in a second circle sector of the pipeline. 30