Monopile coating method, monopile and monopile coating system

Abstract

A monopile coating method is disclosed that includes loading a monopile on a roller support, the roller support including a rotating means for rotating the monopile when the monopile is loaded on the roller support, the rollers supporting the monopile and positioned at one or more locations along an axis of the monopile when the monopile is loaded on the roller support, applying a thermally sprayed metal coating, such as an aluminum or zinc aluminum coating, to portions of a circumferential outer surface of the monopile corresponding to the one or more locations, and compressing at least a portion of the thermally sprayed metal coating by rotating the monopile using the roller support. Monopiles and monopile coating systems are also disclosed.

Description

[Technical field]

[0001]

[0001] The present disclosure relates to the provision of a monopile coating method, a monopile, and a monopile coating system. [Background technology]

[0002]

[0002] An important issue in the 21st century is how to reduce greenhouse gas emissions. To combat climate change, it is foreseen that more and more electricity should be generated using renewable resources. For example, electricity may be generated using wind turbines, preferably offshore wind turbines.

[0003]

[0003] Offshore wind turbines require a solid and reliable foundation. Compared to other options, monopile foundations are popular due to their low manufacturing costs, low transportation and installation costs, and low risk profile due to their flawless track record. Over 80% of the wind turbines currently installed in the North Sea are based on monopile foundations.

[0004]

[0004] Currently, the typical length of a monopile is 50-90 m, the typical diameter of a monopile is more than 8 m, and the typical wall thickness of a monopile is 60-120 mm. The typical weight of a monopile can be more than 1000 tonnes.

[0005]

[0005] Monopiles are typically made of steel and may be formed by welding together several shells. The shells may be formed by rolling one or more steel plates in a cylindrical / conical shape and welding the connecting sides of the rolled plates. The advantage of such a production process is that large sized tubular objects may be formed.

[0006]

[0006] In recent years, there has been development towards increasing shell diameter, decreasing shell steel plate thickness and increasing monopile length. This development is expected to continue at least into the foreseeable future. It is therefore expected that there will be a future need for monopiles longer than 90m and / or having diameters greater than 8m and / or having wall thicknesses less than 60mm.

[0007]

[0007] Offshore foundations are exposed to very aggressive environments, classified according to ISO 12944-2:2017 as CX / lm4 category (offshore class, extremely corrosive), which means that a number of corrosion protection measures must be taken to achieve a minimum service life of more than 25 years.

[0008]

[0008] Corrosion protection measures include coating the monopiles. There are a number of different coating systems, each with its advantages and disadvantages. Coating systems include thermally sprayed metallic coatings (TSZA, Thermal Sprayed Zinc Aluminum, or TSA, Thermal Sprayed Aluminum) and very strong organic two-component coatings (epoxy). Both systems act as a barrier to water and oxygen to prevent rust formation, and the metallic systems provide additional galvanic (electrochemical) protection.

[0009] The monopile coating process may be carried out in a coating hall, in which the environment may be controlled to be particularly suitable for coating the monopile, and which may be equipped with special equipment for coating the monopile.

[0010]

[0010] Inside the coating hall an explosive atmosphere may exist, i.e. due to the presence of solvents and / or liquid volatile particles an explosive gas or dust atmosphere may exist. Therefore any equipment used in the coating hall should meet the safety requirements for such an environment. There are laws and / or regulations that describe the safety requirements for equipment used in explosive atmospheres, for example the ATEX (Equipment intended for use in explosive atmospheres) Directive of the EU (European Union). Any equipment used inside the coating hall should comply with these laws and / or regulations.

[0011] In a monopile coating process, some portions of the coating may be applied automatically and other portions of the coating may be applied manually.

[0012]

[0012] A disadvantage of manually applying the coating is that coating holes equipped for automatically applying the coating may not be suitable for manually applying the coating, which may require moving the monopile between the coating holes, which may be expensive depending on the size and weight of the monopile.

[0013] A further disadvantage of manually applying a coating is that it may be necessary to perform automatic and manual coatings in sequence, which has the disadvantage of lengthening the overall coating process, which may lead to higher costs and lower productivity.

[0014]

[0014] A further disadvantage of manually applying the coating is that due to the size and weight of the monopile, there is a risk of accidents at the work site during the manual application of the coating process. Although the risk of accidents at the work site may be reduced by various safety measures, it may be inherently safer to apply the coating automatically.

[0015]

[0015] US2004 / 062875A1 (hereinafter D1) describes a coating apparatus for coating a wound device including a device rotor having a pair of rollers and a jet nozzle. The jet nozzle produces a jet of coating material which is directed into a gap between the pair of rollers. Most of any jet that is not deposited on the wound device during the coating process passes through the gap between the rollers. Paragraph 13 of D1 states that "The coating process is particularly suitable for small wound devices, e.g. small medical devices having a cylindrical shape, e.g. catheters and stents." D1 does not relate to monopiles.

[0016]

[0016] JP2020066773A (hereinafter referred to as D2) describes a film-forming device including a rotary roller for rotating a tube and a spraying portion for spraying a thermal spraying material discharged from a storage tank for storing the thermal spraying material to form a film on the tube rotated by the rotary roller from a direction substantially perpendicular to a tangent of a circle related to the cross section of the tube. Paragraph 20 describes that the tube T1 is made of metal and has a diameter of more than 200 mm and less than 1000 mm. The tube is an object that is typically produced by forming under high pressure or high tensile force. The advantage of such a production process is that the geometric precision (e.g., cylindricity and straightness) can be higher than the geometric precision typically realized by adding cylindrical and conical parts to each other, for example in the production of monopiles. The disadvantage of a typical production process for tubes is that it is only possible up to limited dimensions. D2 does not concern monopiles.

[0017]

[0017] JP2017140597A (hereinafter referred to as D3) describes a frame spray processing device having a blast section for performing a blast process on a substrate, a frame spray section for performing a frame spray process, a rotary device for rotating the substrate, and a plurality of roller devices having rollers and a control section for rotatably supporting the substrate from below, and a carriage for moving the substrate in a longitudinal direction by arranging the blast section and the frame spray section on a moving path of the substrate, wherein the blast section includes a blast tray for recovering a blast gun and a blast material, the frame spray section includes a frame spray gun and a frame spray tray for recovering a frame spray material, the plurality of roller devices are arranged in a linear shape in the longitudinal direction of the substrate, and each roller is vertically movable between a support position for contacting the substrate and a retracted position where it is moved downward, and the control section continuously moves the roller to the retracted position when the roller passes the arrangement positions of the blast tray and the frame spray tray when the roller moves in response to the movement of the substrate so that the roller does not collide with the blast tray and the frame spray tray. D3 does not relate to monopiles. Moreover, since D3 relates to flame spray processing devices, the devices are unsuitable for use in explosive atmospheres, since open flames should not be used in explosive atmospheres.

[0018]

[0018] The above information is presented as background information only to aid in the understanding of the present disclosure. No determination has been made, and no assertion has been made, as to whether or not any of the above may be applicable as prior art with respect to the present disclosure. Summary of the Invention

[0019] Technical issues

[0019] There is a long felt need for a monopile coating method that reduces the need to manually apply the coating in favor of automatic coating. Reducing the amount of manual coating required in favor of automatic coating may allow for lower costs and / or higher productivity and / or a safer working environment and / or other benefits.

[0020]

[0020] Various attempts have been made to address this problem. In an automated coating method, the monopile may be placed in a controlled environment, for example a coating hall. Before the coating is applied, the surface may be pretreated for coating. The coating may then be applied to the circumferential outer surface of the monopile by using a device for automatically spraying the coating onto the circumferential outer surface of the monopile.

[0021]

[0021] In practice, it is convenient to apply the coating to the circumferential outer surface of the monopile by moving a device for automatically spraying the coating along the longitudinal direction of the monopile while spraying the coating and by rotating the monopile about its axis.

[0022] It is noted that the monopile is typically much larger and heavier than the device for automatically spraying the coating, and therefore it is more convenient to move the device for automatically spraying the coating along the length of the monopile than to move the monopile itself.

[0023]

[0023] However, due to the size of the monopile, it is impractical to move a device for automatically spraying the coating around the circumference of the monopile, which may have a diameter of 8 m or more, so it is preferable to rotate the monopile instead in order to coat the outer circumferential surface of the monopile.

[0024] Typically, the monopiles are coated with an epoxy coating. This may be done automatically or manually.

[0025] In the known method of coating monopiles, the surface of the monopile is first cleaned as a pretreatment for the coating. The monopile is then moved to a coating hall equipped with a device for spraying the coating. The coating is applied using this device. After the coating process, the monopile is removed and a further coating is applied manually. A quality control procedure is then carried out.

[0026]

[0026] Therefore, there remains a need for a monopile coating method that is convenient for automated coating and requires less manual coating. Technical solutions

[0027] However, as discussed above, developments in the field of monopile manufacturing have been made towards increasing monopile diameter, decreasing monopile wall thickness and increasing monopile length. This implies that monopiles are becoming heavier and longer, but not stiffer. If the monopile supports and devices for rotating the monopile are located only proximal to the ends of the monopile, the supports and devices for rotating the monopile should also be adapted to support and rotate heavier monopiles. Moreover, long and heavy monopiles may bend under their own weight. Therefore, there is a need for a monopile coating method in which the monopile supports and devices for rotating the monopile are located at multiple positions along the length of the monopile.

[0027]

[0028] The monopile can be supported on a roller support positioned at at least one location along the monopile's axis. Such a roller support may be powered, for example, using an electric motor, and may serve as a device for rotating the monopile. A coating, for example an epoxy coating, can be automatically applied to the monopile supported and rotated by the roller support positioned at at least one location along the monopile's axis.

[0028]

[0029] However, the weight of the monopile exerts a large pressure on the contact point between the roller support and the monopile. In fact, the pressure on the contact point between the roller support and the monopile may be estimated to be more than 1 GPa. Moreover, in fact, the geometric accuracy of the monopile, e.g. straightness and cylindricity, may be relatively low, which may result in axial drift forces during rotation. This would result in the coating being subjected to large compressive stresses and being expected to be damaged if the coating is applied to a portion of the circumferential outer monopile surface that corresponds to at least one position along the monopile axis where the roller is located. Therefore, only the portion of the circumferential outer monopile surface that does not correspond to at least one position along the monopile axis where the roller is located can be coated automatically, whereas the portion of the circumferential outer monopile surface that corresponds to at least one position along the monopile axis where the roller is located needs to be coated manually. In fact, the portion of the circumferential outer monopile surface that corresponds to at least one position along the monopile axis where the roller is located may include approximately one third of the entire circumferential outer monopile surface. It is further stated that manual coating can only be performed after the monopile has been released from the roller support, and that the monopile cannot be rotated during manual coating, because placing the monopile on the roller support and rotating the monopile would damage the coating. The monopile is still supported by the roller support, but even if the monopile is moved so that the roller supports are positioned in different positions, the coating that is automatically applied to these different positions would be damaged by the roller support on which the monopile is positioned. Therefore, moving the monopile would only lead to different parts of the monopile having to be manually coated.This means that in order to coat the portion of the circumferential outer monopile surface corresponding to at least one position along the monopile axis where the roller is positioned, the monopile needs to be removed from the roller support resting on a stationary support, a scaffold needs to be constructed around the monopile so that the entire surface is accessible to the person applying the coating, and then the coating needs to be applied manually. Thus, manually applying a coating to the portion of the circumferential outer monopile surface corresponding to at least one position along the monopile axis where the roller is positioned is both time consuming as well as costly.

[0029]

[0030] In a first aspect of the present disclosure, there is provided a monopile coating method comprising: loading a monopile having a diameter of 8 m or greater onto a roller support, the roller support comprising a rotating means for rotating the monopile when it is loaded onto the roller support, the rollers supporting the monopile and positioned at one or more locations along an axis of the monopile when it is loaded onto the roller support, applying a thermally sprayed metal coating, such as an aluminum or zinc aluminum coating, to portions of a circumferential outer surface of the monopile corresponding to the one or more locations, and compressing at least a portion of the thermally sprayed metal coating by rolling the monopile using the rollers.

[0030]

[0031] The inventors have surprisingly found that applying a thermally sprayed metal coating, such as an aluminum or zinc aluminum coating, to portions of the circumferential outer surface of the monopile corresponding to one or more locations, and compressing the thermally sprayed metal coating by rotating the monopile using a roller support, allows the portions of the circumferential outer surface of the monopile corresponding to one or more locations to be coated, even though the thermally sprayed metal coating is subjected to pressure exerted by the roller support on the thermally sprayed metal coating. Although the thermally sprayed metal coating is subjected to large compressive stresses, which change the structure and properties of the thermally sprayed metal coating, the thermally sprayed metal coating remains adherent to the monopile and suitable for corrosion protection after compression.

[0031]

[0032] When a thermal sprayed metal coating is applied, it has a ductile and porous structure. Compressing the thermal sprayed metal coating reduces the porosity. Surprisingly, the adhesive properties of the thermal sprayed metal coating remain. Compressing the thermal sprayed metal coating makes it less permeable. A less permeable coating may have enhanced corrosion protection properties.

[0032]

[0033] It is further noted that once the sprayed metal coating is applied, it solidifies rapidly. Therefore, even if the coating must be compressed after it solidifies, this does not slow down the monopile coating process. Applying and compressing the sprayed metal coating may take less time than applying more conventional coatings, such as epoxy coatings. Also, the total time required to coat the monopile may be reduced because the monopile does not need to be moved between applying and compressing at least a portion of the sprayed metal coating on portions of the circumferential outer surface of the monopile corresponding to one or more locations and applying the coating to other portions of the monopile.

[0033]

[0034] Advantageously, compressing at least a portion of the sprayed metal coating comprises compressing the sprayed metal coating to reduce the thickness of the coating by 15% to 80%, preferably by 20% to 70%, more preferably by 25% to 60%, and most preferably by 30% to 50%. In other words, after compression, the layer has a thickness that is 20% to 85%, preferably 30% to 80%, more preferably 40% to 75%, and most preferably 50% to 70% of the original layer thickness. Due to the high pressure on the coating, the thickness of the coating is significantly reduced. Reducing the thickness of the coating by compressing it reduces the porosity of the coating, thereby reducing the permeability of the coating and improving the anti-corrosion properties of the coating.

[0034]

[0035] Advantageously, compressing at least a portion of the sprayed metal coating comprises rotating the monopile an average of at least 10, preferably at least 20, more preferably at least 25, and most preferably at least 30 times. Compressing the sprayed metal coating by rotating the monopile multiple times may increase the amount of compression of the sprayed metal coating. In fact, the monopile may be rotated during the application of the sprayed metal coating. So, in practice, it is possible that not all portions of the circumferential outer surface of the monopile corresponding to one or more positions where the roller support is located are compressed the same number of times.

[0035]

[0036] Advantageously, after compressing, the sprayed metal coating includes a surface with a smooth, shiny and uniform appearance, without cracks, laminations, lumps or other visible defects. Compressing the sprayed metal coating reduces porosity and flattens the surface. Because of this, the surface of the coating looks visually different after compressing compared to the uncompressed sprayed metal coating. A further advantage of a smooth surface is that it becomes difficult for microorganisms to attach to the surface. Since microorganisms can cause corrosion, a smooth surface may contribute to corrosion protection.

[0036]

[0037] Advantageously, the monopile coating method further comprises applying a protective material, such as a polymer foam or a rubber sheet, over the sprayed metal coating after applying the sprayed metal coating and before or during compressing at least a portion of the sprayed metal coating. Applying the protective material before or during compressing at least a portion of the sprayed metal coating may help protect the coating from some forms of mechanical damage and keep the surface from contamination.

[0037]

[0038] Advantageously, the monopile coating method further comprises applying a sealer onto the sprayed metal coating after compressing the sprayed metal coating. A sealer is a low volume solid liquid coating that penetrates any surface and fills its porosity. Applying the sealer after compressing further reduces the porosity of the coated monopile surface. The lower porosity contributes to improving the anti-corrosion properties of the coating.

[0038]

[0039] Advantageously, the monopile coating method further comprises applying a further coating over the sprayed metal coating after compressing the sprayed metal coating. For example, there may be a requirement to apply a high visibility coating to the portion of the monopile that is intended to be elevated above sea level after installation. Indeed, there may be other reasons why it is necessary to apply an additional coating over the compressed sprayed metal coating.

[0039]

[0040] Advantageously, the portion of the circumferential outer surface of the monopile corresponding to one or more locations has a width that varies from 0.2m to 3m, preferably from 0.4m to 2.5m, more preferably from 0.5m to 2m, most preferably from 0.7m to 1.5m, based on which type of roller support is used. The width of the metal coating at one or more locations where the roller support is located depends on which type of roller support is used. The width of the metal coating should be at least as large as the width of the roller support used. However, it may be advantageous if the width of the metal coating is larger than the width of the roller support used. For example, if the width of the roller support is approximately 1m, it may be beneficial if the width of the metal coating is 1.5m. As another example, if the width of the roller support is approximately 1.4m, it may be beneficial if the width of the metal coating is approximately 2m. If the width of the metal coating is larger than the width of the roller support used, this allows room for overlap application of adjacent coating systems to the metal coating. In fact, leaving some room for overlap simplifies the coating method while ensuring that no part of the monopile is left uncoated.

[0040]

[0041] Advantageously, during compression, the compressive stress on the sprayed metal coating at the contact point is greater than 500 MPa, preferably 750 MPa, more preferably 1 GPa, most preferably 1.5 GPa. The compressive stress depends on the weight of the monopile and the roller support used. Applying a higher compressive stress allows a stronger compression of the coating thickness, thereby leading to a lower porosity and therefore increased corrosion protection.

[0041]

[0042] Advantageously, the monopile includes a longitudinal submerged arc weld, and the monopile coating method further includes ground flashing the longitudinal submerged arc weld before placing the monopile on the roller support. The monopile may be formed by welding together a number of shells. The shells may be formed by rolling one or more steel plates in a cylindrical / conical shape and welding the connection sides of the rolled plates. Thus, when the monopile is formed, it includes a longitudinal submerged arc weld. As a pre-treatment for the coating method, the longitudinal submerged arc weld should be ground flashed. This may prevent stress concentration during welding, which may cause fatigue cracks.

[0042]

[0043] Advantageously, the monopile coating method further comprises blast cleaning portions of the circumferential outer surface of the monopile corresponding to the one or more locations prior to applying the thermally sprayed metal coating. Optionally, the blast cleaning is carried out using open jet grit blasting, preferably with steel or mineral grit abrasives, or using automated turbine blast cleaning, preferably with steel grit abrasives. Optionally, the blast cleaning comprises pre-treating the surface to meet ISO 8501-1 Sa 3 (white metal) standard or ISO 8501-1 Sa2 1 / 2 standard or SSPC-SP10 / NACE No. 2 near-white blast cleaning standard (standard last revision January 2007) or SSPC-SP 5 / NACE No. 1, white metal blast cleaning standard (last revision January 2007). Optionally, blast cleaning comprises pretreating the surface to have an acute angle profile depth in the range of 40 μm to 150 μm, preferably 50 μm to 125 μm, more preferably 60 μm to 115 μm, most preferably 80 μm to 105 μm. Pretreating portions of the circumferential outer surface of the monopile corresponding to one or more locations using blast cleaning prior to applying the thermal sprayed metal coating ensures that the surface is particularly suitable for applying the thermal sprayed metal coating. By pretreating the surface particularly well, adhesion with the thermal sprayed metal coating is improved.

[0043]

[0044] According to a second aspect of the present disclosure, there is provided a monopile, the monopile being coated using a monopile coating method as defined in any one of claims 1-13.

[0044]

[0045] In a third aspect of the present disclosure, there is provided a monopile coating system comprising a roller support and a thermal spraying device, the roller support comprising a rotating means for rotating a monopile having a diameter of at least 8 m when the monopile is placed on the roller support, the roller for supporting the monopile and positioned at one or more positions along the axis for placing the monopile on the roller support, and the thermal spraying device configured to apply a thermally sprayed metal coating, for example an aluminium or zinc aluminium coating, to portions of a circumferential outer surface of the monopile corresponding to the one or more positions. Advantageously, the monopile coating system is further configured to perform a monopile coating method according to any one of claims 2 to 13.

[0045]

[0046] In a fourth aspect of the present disclosure, there is provided a method of coating comprising applying a thermally sprayed metal coating, such as an aluminum or zinc aluminum coating, to a surface and compressing the thermally sprayed metal coating.

[0046]

[0047] When a thermal sprayed metal coating is applied, it has a ductile and porous structure. Compressing the thermal sprayed metal coating reduces the porosity. Surprisingly, the adhesive properties of the thermal sprayed metal coating remain. Compressing the thermal sprayed metal coating makes it less permeable. A less permeable coating may have enhanced corrosion protection properties.

[0047]

[0048] Advantageously, compressing the sprayed metal coating comprises compressing the sprayed metal coating to reduce the thickness of the coating by 15% to 80%, preferably by 20% to 70%, more preferably by 25% to 60%, and most preferably by 30% to 50%. In other words, after compression, the layer has a thickness that is 20% to 85%, preferably 30% to 80%, more preferably 40% to 75%, and most preferably 50% to 70% of the original layer thickness. Reducing the thickness of the coating by compressing it reduces the porosity of the coating, thereby reducing the permeability of the coating and improving the anti-corrosion properties of the coating.

[0048]

[0049] Advantageously, after compressing, the sprayed metal coating includes a surface with a smooth, shiny and uniform appearance, without cracks, laminations, lumps or other visible defects. Compressing the sprayed metal coating reduces porosity and flattens the surface. Because of this, the surface of the coating looks visually different after compressing compared to the uncompressed sprayed metal coating. A further advantage of a smooth surface is that it becomes difficult for microorganisms to attach to the surface. Since microorganisms can cause corrosion, a smooth surface may contribute to corrosion protection.

[0049]

[0050] Advantageously, the coating method further comprises applying a protective material, such as a polymer foam or a rubber sheet, over the sprayed metal coating after applying the sprayed metal coating and before or during compressing the sprayed metal coating. Applying a protective material before or during compressing the sprayed metal coating may help protect the coating from some forms of mechanical damage and keep the surface from contamination.

[0050]

[0051] Advantageously, the coating method further comprises applying a sealer onto the sprayed metal coating after compressing the sprayed metal coating. A sealer is a low volume solid liquid coating that penetrates any surface and fills its porosity. Applying the sealer after compressing further reduces the porosity of the coated monopile surface. The lower porosity contributes to improving the anti-corrosion properties of the coating.

[0051]

[0052] Advantageously, the coating method further comprises applying a further coating over the sprayed metal coating after compressing the sprayed metal coating.

[0052]

[0053] Advantageously, during compressing, the compressive stress on the sprayed metal coating is greater than 500 MPa, preferably 750 MPa, more preferably 1 GPa, most preferably 1.5 GPa. Applying a higher compressive stress allows for a stronger compression of the coating thickness, thereby leading to lower porosity and therefore increased corrosion protection.

[0053]

[0054] Advantageously, the coating method further comprises blast cleaning the surface prior to applying the thermally sprayed metal coating. Optionally, the blast cleaning is carried out using open jet grit blasting, preferably with steel or mineral grit abrasives, or using automated turbine blast cleaning, preferably with steel grit abrasives. Optionally, the blast cleaning comprises pre-treating the surface to meet the ISO 8501-1:2007 Sa 3 (white metal) standard or the ISO 8501-1 Sa2 1 / 2 standard or the SSPC-SP10 / NACE No.2 near-white blast cleaning standard (standard last revision January 2007) or the SSPC-SP 5 / NACE No.1, white metal blast cleaning standard (last revision January 2007). Optionally, blast cleaning includes pretreating the surface to have an acute angle profile depth in the range of 40 μm to 150 μm, preferably 50 μm to 125 μm, more preferably 60 μm to 115 μm, most preferably 80 μm to 105 μm. Pretreating the surface using blast cleaning prior to applying the thermal sprayed metal coating ensures that the surface is particularly suitable for applying the thermal sprayed metal coating. By pretreating the surface particularly well, adhesion with the thermal sprayed metal coating is improved.

[0054]

[0055] In a fifth aspect of the present disclosure, there is provided a coating, the coating being obtainable, obtained and / or directly obtained by using the monopile coating method of the first aspect, or obtainable, obtained and / or directly obtained by using the coating method of the fourth aspect. Advantageously, the coating may be used on a monopile.

[0055]

[0056] In a sixth aspect of the present disclosure, there is provided a coating system comprising a thermal spraying apparatus and a means for compressing the thermally sprayed metal coating, the thermal spraying apparatus configured to apply a thermally sprayed metal coating, such as an aluminum or zinc aluminum coating, to a surface, and the means for compressing the thermally sprayed metal coating configured to compress the thermally sprayed metal coating. Advantageously, the coating system is further configured to perform the monopile coating method of the first aspect or to perform the coating method of the fourth aspect.

[0056]

[0057] Aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings which are schematic in nature and, therefore, are not necessarily to scale. Moreover, like reference symbols in the drawings refer to like elements. In the accompanying drawings: [Brief description of the drawings]

[0057] [Figure 1] FIG. 1 illustrates a schematic of a monopile coating method according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 illustrates a schematic of a monopile coating method according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 illustrates a schematic side view of a monopile on a roller support according to an embodiment of the present disclosure. [Figure 4] FIG. 4 illustrates a schematic front view of a monopile on a roller support according to an embodiment of the present disclosure. [Diagram 5] FIG. 5 illustrates, in accordance with an embodiment of the present disclosure, blast cleaning portions of a circumferential outer surface of a monopile that correspond to one or more locations along the axis of the monopile where a roller support is positioned. [Figure 6] FIG. 6 illustrates, in accordance with an embodiment of the present disclosure, the application of thermally sprayed metal to portions of the circumferential outer surface of the monopile that correspond to one or more locations along the axis of the monopile where the roller supports are positioned. [Figure 7]FIG. 7 illustrates a schematic of compressing a thermally sprayed metal coating by rolling the monopile using a roller support, according to an embodiment of the present disclosure. [Figure 8] FIG. 8 illustrates a schematic of a monopile according to an embodiment of the present disclosure. [Figure 9A] FIG. 9A illustrates a schematic of a structure of a thermally sprayed metal coating prior to compressing the thermally sprayed metal coating, according to an embodiment of the present disclosure. [Figure 9B] FIG. 9B illustrates a schematic of the structure of a thermally sprayed metal coating after compressing the thermally sprayed metal coating, according to an embodiment of the present disclosure. Detailed Description

[0058] FIG. 1 is a flow chart showing a schematic diagram of the monopile coating method.

[0059]

[0059] In step 101, the monopile 301 is placed on roller supports 302-305.

[0060]

[0060] In practice, the roller supports 302-305 may be located in a coating hall. The environment in the coating hall may be controlled to be particularly suitable for coating and may be equipped with specialised coating equipment. The coating hall may be an ATEX work site. The monopile coating process may be carried out in any suitable indoor or outdoor location, although the use of a coating hall may be beneficial to the coating process and allow efficient application of a high quality coating.

[0061]

[0061] The monopile 301 may be obtained by welding together several shells. The shells may be formed by rolling one or more steel plates in a cylindrical / conical shape and welding the connecting sides of the rolled plates. In fact, the welding to obtain the monopile is not carried out inside a coating hall, but for example inside a welding hall, where the environment is controlled to be particularly suitable for welding and which is equipped with special welding equipment. The advantage of this production process is that monopiles with large dimensions can be provided. However, the geometrical accuracy (for example cylindricity and straightness) may be much lower compared to tubes, which are produced, for example, by forming under high pressure or high tensile forces.

[0062]

[0062] Before coating, the uncoated monopile 301 is transported to a coating hole. To transport the monopile 301, it is possible to use a trailer adapted to carry the weight of the monopile 301. Additionally or alternatively, the monopile 301 may be transported using a crane and / or a boat and / or other suitable monopile transport devices. Due to the large size and weight of the monopile 301, transporting the monopile may be costly and unnecessary monopile transport should be avoided.

[0063]

[0063] However, it is also possible to carry out the monopile coating process at the same location as the welding and not transport the monopile 301 to another location. In this case, however, either the welding and coating equipment should be at the same location or the coating equipment should be transported and installed at the welding location when the coating process is carried out. In order to achieve a streamlined and efficient monopile production and coating process, it may be preferable to carry out the production and coating of the monopile in different but nearby locations of the halls, each of which is equipped with suitable equipment.

[0064]

[0064] To place the monopile 301 on the roller supports 302-305, a crane or the like may be used after the monopile has been transported to the coating hall. Additionally or alternatively, the roller supports 302-305 may be mobile. In this case, it may be possible to transport the monopile 301 to the coating hall, for example by using a trailer, and then move the roller supports 302-305 towards the monopile 301. The roller supports 302-305 may be used to lift the monopile 301 from the trailer, which may then be removed. Additionally or alternatively, instead of lifting the monopile 301 using the roller supports 302-305, the monopile 301 may be placed on the roller supports 302-305, after which the trailer bed may be lowered and the trailer may be removed. A person skilled in the art will understand that other ways of placing the monopile 301 on the roller supports 302-305 are also possible.

[0065]

[0065] The monopile 301 is mounted on the roller supports 302-305 such that the roller supports 302-305 are positioned at one or more positions along the axis of the monopile 301. After the monopile 301 is mounted on the roller supports 302-305, the roller supports 302-305 support the weight of the monopile 301.

[0066]

[0066] The roller supports 302-305 are provided with a rotating means for rotating the monopile 301. For example, the roller supports 302-305 may be provided with an electric engine. When the electric engine is running, the rollers on which the monopile 301 rests may be rotated by the electric engine. This then causes the monopile 301 to rotate about its axis.

[0067]

[0067] The loading of the monopile 301 of 101 onto the roller supports 302-305 is described in further detail below with reference to Figs.

[0068]

[0068] In step 102, a thermal sprayed metallic coating is applied.

[0069]

[0069] When the monopile 301 is rotated, the circumferential outer surface of the monopile 301 moves relative to the roller supports 302-305. The rotation of the monopile 301 brings different parts of the circumferential outer surface into contact with the roller supports 302-305. The weight of the monopile applies pressure to the parts of the circumferential outer surface in contact with the roller supports 302-305. This pressure is mainly directed perpendicular to the monopile surface, but the low geometric precision of the monopile may result in drift forces when the monopile is rotated. Thus, the parts of the circumferential outer surface in contact with the roller supports may experience compressive stresses both perpendicular to the surface due to direct pressure as well as parallel to the surface due to drift forces. After the rotation of the monopile 301, a number of bands having the same width as the contact width between the monopile 301 and each of the rollers 302-305 around the monopile 301 will be in contact with at least one of the roller supports 302-305. It should further be noted that roller supports 302-305 may be oriented such that the band contacts multiple roller supports during a single rotation, for example if two roller supports are positioned at the same longitudinal position relative to the monopile.

[0070]

[0070] The sprayed metal coating may be applied to a band on the monopile surface in contact with at least one of the roller supports. The sprayed metal coating may be applied to a portion 501, 502 of the circumferential outer surface of the monopile corresponding to one or more locations at which the roller supports 302-305 are located. Said portion 501, 502 of the circumferential outer surface of the monopile corresponding to one or more locations may comprise a band on the monopile surface in contact with at least one of the roller supports 302-305, and may further preferably comprise an area of ​​the circumferential outer surface directly adjacent to said band.

[0071]

[0071] For example, if the contact width between the monopile 301 and at least one of the respective rollers 302-305 is approximately 1 m, it may be beneficial if the portions 501, 502 of the circumferential outer surface of the monopile corresponding to said at least one position of the respective roller have a width of approximately 1.5 m. As another example, if the contact width between the monopile 301 and at least one of the respective rollers 302-305 is approximately 1.4 m, it may be beneficial if the portions 501, 502 of the circumferential outer surface of the monopile corresponding to said at least one position of the respective roller have a width of approximately 2 m.

[0072]

[0072] A thermally sprayed metal coating is applied to portions of the circumferential outer surface of the monopile corresponding to one or more locations. The thermally sprayed metal coating may include, for example, an aluminum coating or a zinc-aluminum coating. ISO 14919:2015 specifies requirements for the classification of metallic and non-metallic wires (solid and core), rods, and cords processed with the aid of thermal spraying, inter alia by arc and flame spraying. An example of an aluminum coating is type Al99.5 of ISO 14919:2015. An example of a zinc-aluminum coating is type ZnAl15 of ISO 14919:2015. However, other types of thermally sprayed metal coatings may be used.

[0073]

[0073] The thermally sprayed metal coating may be applied to a thickness of approximately 300 to 1000 micrometers, preferably approximately 500 to 800 micrometers, more preferably approximately 600 to 700 micrometers, and most preferably approximately 650 micrometers. An electronic thickness gauge may be used to determine the thickness.

[0074] After application, the thermally sprayed metal coating has a ductile and porous structure.

[0075] Further properties of the thermally sprayed metallic coating are described in more detail below with reference to FIG. 9A.

[0076]

[0076] The application of the thermally sprayed metallic coating at 102 is described in further detail below with reference to FIG.

[0077]

[0077] In step 103, the sprayed metal coating is compressed by the weight of the monopile on the roller supports 302-305.

[0078]

[0078] The sprayed metal coating applied to a band on the monopile surface in contact with at least one of the roller supports 302-305 is compressed by rotating the monopile 301. Because the sprayed metal coating may be applied to the outside of the band on the monopile surface in contact with at least one of the roller supports 302-305, it is possible that parts, but not all, of the sprayed metal coating are compressed.

[0079]

[0079] Due to the weight of the monopile 301, the compressive stress on the sprayed metal coating at the contact points between the roller supports 302-305 and the monopile 301 may be greater than 500 MPa, preferably greater than 750 MPa, more preferably greater than 1 GPa, and most preferably greater than 1.5 GPa.

[0080]

[0080] It should be noted that the compressive stresses may include a component perpendicular to the monopile surface due to the weight of the monopile resting on the roller support, and one or more components parallel to the monopile surface, for example due to drift forces. Drift forces may be caused by rotating the monopile with geometric imperfections. In this disclosure, the compressive stresses will be primarily described as including a component perpendicular to the monopile surface, but drift forces are typically present in practice and may contribute to one or more of the technical effects described in this disclosure.

[0081]

[0081] To compress the sprayed metal coating, it is sufficient to rotate the monopile 301 only once. In fact, depending on the positioning of the roller support, a portion of the circumferential outer surface may come into contact with the roller support multiple times during a single rotation. For compression, it is sufficient that a portion of the circumferential outer surface comes into contact with the roller support only once. Furthermore, it may not be necessary to compress a complete band around the monopile, so that rotating the monopile in this way less than one rotation may be sufficient. However, alternatively, it is possible to compress the sprayed metal coating by rotating the monopile 301 multiple times. For example, the monopile 301 may be rotated at least 10 times, preferably at least 20 times, more preferably at least 25 times, and most preferably at least 30 times. Compressing the sprayed metal coating by rotating the monopile 301 multiple times may increase the amount of compression of the sprayed metal coating. In fact, the monopile 301 may be rotated during the application of the sprayed metal coating. So, in practice, it is possible that not all portions of the circumferential outer surface of the monopile corresponding to one or more locations where the roller supports 302-305 are positioned are compressed the same number of times. Furthermore, it should be noted that the monopile 301 may be rotated further during subsequent coating of the remainder of the monopile, further increasing the number of times that the sprayed metal coating is compressed.

[0082]

[0082] Due to the high compressive stress (which is a result of the weight of the monopile 301) and, optionally, the number of revolutions of the monopile 301, the thickness of the sprayed metal coating may be reduced. The thickness of the coating may be reduced by 15% to 80%, preferably by 20% to 70%, more preferably by 25% to 60%, and most preferably by 30% to 50%. In other words, after compression, the layer has a thickness which is 20% to 85%, preferably by 30% to 80%, more preferably by 40% to 75%, and most preferably by 50% to 70% of the original layer thickness. Reducing the thickness of the sprayed metal coating by compressing the coating may reduce the porosity of the sprayed metal coating, thereby reducing the permeability of the sprayed metal coating, thereby improving the anti-corrosion properties of the sprayed metal coating.

[0083]

[0083] For example, if a thermally sprayed aluminum coating (e.g., type Al99.5 of ISO 14919:2015) is applied to a thickness of 700 micrometers and subjected to a compressive stress of approximately 1 GPa by rotating the monopile 25 times, the thickness after compression may be reduced to 350 micrometers.

[0084]

[0084] As another example, if a thermally sprayed aluminum zinc coating (e.g., type ZnAl15 of ISO 14919:2015) is applied to a thickness of 700 micrometers and subjected to a compressive stress of approximately 1 GPa by rotating the monopile 25 times, the thickness after compression may be reduced to 450 micrometers.

[0085] Surprisingly, it has been found that the adhesive properties of the thermally sprayed metal coating do not deteriorate with compression.

[0086]

[0086] After compacting, the sprayed metal coating may include a surface having a smooth, shiny and uniform appearance, free of cracks, laminations, lumps or other visible defects. Compacting the sprayed metal coating may reduce porosity and may flatten the surface of the coated monopile 301. For this reason, the surface of the coated monopile 301 after compacting may appear visually different compared to the uncompressed sprayed metal coating surface, e.g., the surface of the monopile 301 before compaction, or to a portion of the monopile surface that is coated with the sprayed metal coating but is not compressed, e.g., an area of ​​the circumferential outer surface of the monopile 301 directly adjacent to a band on the monopile surface that contacts at least one of the roller supports 302-305. A further advantage of a smooth surface is that it becomes difficult for microorganisms to attach to the surface. Since microorganisms can cause corrosion, a smooth surface may contribute to corrosion protection. Compacting the sprayed metal coating is described in more detail below with reference to FIG. 7. Further properties of the thermally sprayed metal coating after compression are described in more detail below with reference to FIG. 9B.

[0087]

[0087] It should be noted that instead of compressing the sprayed metal coating by rotating the monopile, it is also possible to compress the sprayed metal coating in a different manner. For example, rollers different from the roller supports 302-305 may be used to compress the sprayed metal coating. Pressure may be applied via such rollers. Additionally or alternatively, the sprayed metal coating may be compressed using a press, for example a hydraulic press or a mechanical press. Additionally or alternatively, the sprayed metal coating may be compressed using other suitable means for compressing the sprayed metal coating.

[0088] It should also be noted that instead of applying the sprayed metal coating to the monopile surface, it is also possible to apply the sprayed metal coating to the surface of another object. After applying the sprayed metal coating, this coating may then be compressed. This makes it possible to coat the surface of another object with a coating that is particularly suitable for corrosion protection.

[0089]

[0089] Thus, a coating method may include applying a thermally sprayed metal coating to a surface and compressing the coating.

[0090]

[0090] Figure 2 is a flow chart showing a schematic diagram of a monopile coating method. Figure 2 is similar to Figure 1, but with the addition of some optional steps. Some of the steps in Figure 2 are the same as Figure 1, and detailed descriptions of these steps are omitted.

[0091]

[0091] During monopile manufacture, a submerged arc welding process may be used to assemble the monopile 301. In step 201, the submerged arc weld may be ground flashed as a pre-treatment for the monopile coating process. Ground flashing the submerged arc weld may help to eliminate stress concentrations or mechanical imperfections during the weld passing over rollers.

[0092] Step 101 in FIG. 2 may be the same as step 101 in FIG.

[0093]

[0093] After the monopile 301 is mounted on the roller supports 302-305, but prior to application of the thermally sprayed metal coating, the monopile surface may be pre-treated for coating.

[0094]

[0094] As a pretreatment for coating, blast cleaning is performed in step 202.

[0095]

[0095] The portions 501, 502 of the monopile 301 to be coated with the thermal sprayed metal coating may be blast cleaned. Pre-treating the surface using blast cleaning prior to applying the thermal sprayed metal coating ensures that the surface is particularly suitable for applying the thermal sprayed metal coating. By pre-treating the surface particularly well, adhesion with the thermal sprayed metal coating is improved.

[0096]

[0096] Blast cleaning 202 may be performed in various ways, for example, using open jet grit blasting, preferably with steel or mineral grit abrasives, or using automated turbine blast cleaning, preferably with steel grit abrasives. To ensure a consistent high quality of the blast cleaning, the blast cleaning may be performed to meet the ISO 8501-1:2007 Sa 3 (white metal) standard or the ISO 8501-1 Sa2 1 / 2 standard or the SSPC-SP10 / NACE No. 2 near-white blast cleaning standard (standard last revision January 2007) or the SSPC-SP 5 / NACE No. 1, white metal blast cleaning standard (last revision January 2007). For preparing a surface for application of a thermally sprayed metal coating, it is beneficial for the surface to have an acute angle profile depth in the range of 40 μm to 150 μm, preferably 50 μm to 125 μm, more preferably 60 μm to 115 μm, and most preferably 80 μm to 105 μm.

[0097]

[0097] Blast cleaning 202 is described in further detail below with reference to FIG.

[0098] Step 102 in FIG. 2 may be the same as step 102 in FIG.

[0099]

[0099] A protective material may be applied to the coating in step 203 before and / or during compression of the sprayed metal coating. A protective material may be applied before compression. A protective material may be applied either during compression, while compression is taking place, or during one or more parts of the compression process. The same protective material may be applied multiple times. Different protective materials may be applied simultaneously and / or sequentially. It is also possible to omit step 203 and not apply any protective material.

[0100] After application of the sprayed metal coating, a protective material may be applied over the coating. These protective materials may be applied before and / or during compression of the sprayed metal coating. The protective materials may be of plastic, synthetic rubber and / or metal composition. The protective materials may be in the form of a foam, for example a polymer foam, or in the form of a sheet. Examples of polymer foams are ethylene-vinyl acetate foam, polyethylene foam, nitrile rubber foam, polychloroprene foam, polyamide foam, polypropylene foam, polystyrene foam, polyurethane foam, polyvinyl chloride foam or silicone foam. However, other types of polymer foams may be used. Rubber sheets may be suitable for use as protective materials. Applying a protective material may help protect the coating from some forms of mechanical damage and keep the surface from contamination.

[0101]

[0101] Step 103 in FIG. 2 may be the same as step 103 in FIG.

[0102]

[0102] After the sprayed metal coating is compressed, a sealant may be applied over the coating, step 204. The sealant is a low volume solid liquid coating that may penetrate the surface and fill its porosity.

[0103]

[0103] Applying a sealant over the coating may contribute to protecting the coating. Applying a sealant may contribute to reducing the porosity of the compressed coating. Reducing the porosity of the coating may contribute to improving the anti-corrosion properties of the coating.

[0104]

[0104] The sealant may comprise a low volume solids liquid coating material suitable for application over a thermally sprayed metal coating.

[0105]

[0105] In step 205, a further coating may be applied over the coating. For example, the part of the monopile that is to be raised above sea level after installation may be coated with a high visibility coating, for example a yellow coating. Such a high visibility coating on the part of the monopile 301 that is to be raised above sea level may for example be required by regulations. However, there may also be other reasons for applying a layer of a further coating to certain parts or even the whole of the monopile 301.

[0106]

[0106] In practice, it may be possible to apply a coating to other portions of the monopile before applying and compressing at least a portion of the sprayed metal coating onto the portions of the circumferential outer surface of the monopile corresponding to one or more locations, and / or after applying and compressing at least a portion of the sprayed metal coating onto the portions of the circumferential outer surface of the monopile corresponding to one or more locations, and / or at the same time as applying and compressing the sprayed metal coating onto the portions of the circumferential outer surface of the monopile corresponding to one or more locations.

[0107]

[0107] Although not indicated in Figure 1 or Figure 2, quality control may be performed after the coating process to ensure that the coating is of the required quality. Additionally, intermediate quality control may be performed during or after any of the steps of Figure 1 or Figure 2. Performing quality control during the process, for example after a particular step (e.g. after blast cleaning or compaction), reduces the risk that imperfect results in an earlier step will lead to further problems in a later step.

[0108]

[0108] FIG. 3 illustrates a schematic side view of monopile 301 on roller supports 302-305 according to an embodiment of the present disclosure, and FIG. 4 illustrates a schematic front view of monopile 301 on roller supports 302, 303 according to an embodiment of the present disclosure.

[0109]

[0109] It should be noted that even though the figure shows the monopile 301 rotated clockwise, it is also possible to rotate the monopile 301 counterclockwise. Furthermore, it is possible to rotate the monopile 301 using a combination of clockwise and counterclockwise rotations, for example based on practical considerations.

[0110]

[0110] Figures 3 and 4 show the roller supports 302-305 diagrammatically. For supporting and rotating the monopile 301, various types of roller supports 302-305 are suitable. As a specific example, the Deuma turning roll type Z roller support produced by Deuma Positionniersysteme GmbH is suitable for supporting and rotating the monopile 301. However, other types of roller supports 302-305 may also be used. The roller supports 302-305 may differ from each other with regard to the maximum supporting weight, the roller width, the roller surface material or structure, the rotation speed or other properties.

[0111]

[0111] It is possible for one monopile 301 to be supported by different types of roller supports 302-305. For example, one monopile 301 can be supported by at least a first roller support having a width of 1 meter and a maximum supporting weight of 100 tons, and at least a second roller support having a width of 2 meters and a maximum supporting weight of 250 tons.

[0112]

[0112] Those skilled in the art will recognize that the exact placement of the roller supports 302-305 may depend on which roller supports are available as well as the size and weight of the monopile 301. For example, the weight of the monopile 301 should not exceed the combined maximum support weight of the roller supports 302-305. For example, the roller supports 302-305 should be placed such that the weight supported by any one roller support is less than the maximum support weight of that roller support.

[0113]

[0113] Preferably, when multiple roller supports 302-305 are used, the maximum spacing between the roller supports 302-305 is such that the monopile 301 does not appreciably bow under its own weight. For example, the maximum spacing between the roller supports 302-305 along the direction of the axis of the monopile 301 may be approximately 5-10 metres.

[0114]

[0114] Preferably, the roller supports 302-305 are arranged in pairs. Preferably, each pair of rollers comprises two roller supports of the same type. Although it is possible to arrange the roller supports 302-305 differently, arranging the roller supports 302-305 in pairs of roller supports of the same type has the advantage that it provides a particularly stable way of supporting the monopile 301.

[0115]

[0115] Preferably, the roller supports 302-305 are arranged such that the pressure at the contact points between the roller supports 302-305 and the monopile 301 is approximately equal, thereby enabling approximately equal compression of the sprayed metal coating during the compression step 103.

[0116]

[0116] FIG. 5 illustrates generally blast cleaning portions of a circumferential outer surface of a monopile corresponding to one or more locations along the axis of the monopile where a roller support is positioned, according to an aspect of the present disclosure.

[0117]

[0117] Prior to applying the sprayed metal coating of 102, portions 501, 502 of the circumferential outer surface of the monopile 301 corresponding to one or more locations along the axis of the monopile 301 at which the roller supports 302-305 are positioned may be pre-treated using blast cleaning 202. Blast cleaning may be performed using an automated machine and / or manually.

[0118]

[0118] As a pre-treatment for the blast cleaning 202, it is further possible to pre-treat the parts 501, 502 to be blast cleaned using high pressure water cleaning.

[0119]

[0119] The portions 501, 502 of the circumferential outer surface of the monopile 301 corresponding to one or more positions along the axis of the monopile 301 at which the roller supports 302-305 are located may have a width that is equal to or greater than the width of the corresponding roller support. For example, if a particular roller support has a width of 0.8 meters, the corresponding portion may have a width of 0.8 meters. For example, if a particular roller support has a width of 1 meter, the corresponding portion may have a width of 1.5 meters. For example, if a particular roller support has a width of 1.2 meters, the corresponding portion may have a width of 2 meters. It is preferable if the width of the portions of the circumferential outer surface is slightly greater than the width of the corresponding roller, because this leaves room for overlap application of adjacent coating systems to the metal coating. In fact, leaving some room for overlap simplifies the coating method while ensuring that no portion of the monopile 301 is left uncoated.

[0120]

[0120] It is preferable to carry out the blast cleaning 202 after placing the monopile 301 of 101 on the roller supports 302-305. This allows the monopile 301 to be rotated during the blast cleaning 202. If the monopile 301 is rotated during the blast cleaning 202, there is no need to move the blast cleaning equipment 503 vertically. Avoiding the need to move the blast cleaning equipment 503 vertically may simplify the automation of the blast cleaning process. For example, the blast cleaning equipment 503 may be mounted and moved along a horizontal rail extending along the direction of the axis of the monopile 301. Even if the blast cleaning 202 is performed manually, avoiding the need to move the blast cleaning equipment 503 vertically avoids having to carry out the blast cleaning 202 at height, thereby improving the safety of the work site.

[0121]

[0121] FIG. 6 illustrates, in accordance with an embodiment of the present disclosure, the application of thermally sprayed metal to portions of the circumferential outer surface of the monopile that correspond to one or more locations along the axis of the monopile where the roller supports are positioned.

[0122]

[0122] The sprayed metal is applied using thermal spray equipment 601, 602. Such equipment is commercially available and the skilled person will know which equipment is suitable as well as the advantages and disadvantages of the different types of commercially available thermal spray equipment 601, 602. It is noted that thermal spray equipment is commercially available which is particularly suitable for use in explosive atmospheres.

[0123]

[0123] A sprayed metal, for example sprayed aluminum or sprayed zinc aluminum, is applied to portions 501, 502 of the circumferential outer surface of the monopile 301 which correspond to one or more locations along the axis of the monopile 301 at which the roller supports 302-305 are positioned.

[0124]

[0124] Preferably, the monopile 301 is rotated during application of the sprayed metal coating of 102. If the monopile 301 is rotated during application of the sprayed metal coating of 102, there is no need to move the spraying equipment 601, 602 vertically. Avoiding the need to move the spraying equipment 601, 602 vertically may simplify automation of the spraying process. For example, the spraying equipment 601, 602 may be mounted and moved along a horizontal rail extending along the direction of the axis of the monopile 301. Even if application of the sprayed metal coating of 102 is performed manually, avoiding the need to move the spraying equipment 601, 602 vertically avoids having to apply the sprayed metal coating of 102 at a height, thereby improving work site safety.

[0125]

[0125] The sprayed metal solidifies quickly. Therefore, even when applying the sprayed metal to a rotating monopile 301, the rotation speed and direction of the spraying equipment and the monopile can be arranged so that the sprayed metal contacts the roller after it has solidified. In fact, the sprayed metal can solidify instantly. It is preferable for the sprayed metal coating to contact the roller surface after the sprayed metal has solidified, because the adhesion of the liquid metal to the monopile surface may be insufficient to remain on the monopile surface during and after compaction using the roller. Furthermore, it is easier to ensure the uniformity of the sprayed metal coating if the sprayed metal coating contacts the roller surface after the sprayed metal has solidified.

[0126]

[0126] FIG. 7 illustrates generally the compression of a thermally sprayed metal coating by rolling the monopile using a roller support, according to an embodiment of the present disclosure.

[0127]

[0127] The weight of the monopile 301 exerts a large compressive stress on the sprayed metal coating. Depending on the weight of the monopile 301 and the distribution of the roller supports 302-305, the compressive stress on the sprayed metal coating at the contact points may be greater than 500 MPa, preferably 750 MPa, more preferably 1 GPa, and most preferably 1.5 GPa.

[0128]

[0128] When the monopile is rotated, for each roller support and each revolution, a compressive stress is applied to a band with the width of the corresponding roller support around the outer surface of the monopile. When pairs of roller supports are used, the compressive stress is applied twice per revolution.

[0129]

[0129] Sufficient compression of the sprayed metal coating can be achieved in one compression of the sprayed metal coating, which may require less than one rotation, depending on the positioning of the roller support. However, in practice, it may be beneficial to rotate the monopile 301 multiple times to apply compressive stress to the sprayed metal coating multiple times. For example, the monopile 301 may be rotated at least 10 times, preferably at least 20 times, more preferably at least 25 times, and most preferably at least 30 times.

[0130]

[0130] It is possible to apply the sprayed metal coating while rotating the monopile 301. In this case, not all of the portions 501, 502 of the circumferential outer surface of the monopile 301 corresponding to one or more positions along the axis of the monopile 301 at which the roller supports 302-305 are located may be coated at the same time. If not all portions of the portions 501, 502 are coated at the same time, some of the portions 501, 502 that are coated earlier may already be compressed before some of the portions 501, 502 that are coated later are coated. Thus, the total number of times each of the portions 501, 502 is compressed may differ between the portions 501, 502.

[0131]

[0131] It should be noted that in practice, not only the portions 501, 502 of the circumferential outer surface of the monopile 301 corresponding to one or more positions along the axis of the monopile 301 at which the roller supports 302-305 are located are coated, but also the remainder of the monopile 301. Depending on the details of the coating method, it is possible to rotate the monopile 301 a number of times after the portions 501, 502 have been coated and compressed. For example, if the remainder of the monopile 301 is coated after the portions 501, 502 have been compressed, during the coating of the remainder of the monopile 301, the monopile 301 may be rotated, leading to the application of compressive stresses to the portions 501, 502 also during the coating of the remainder of the monopile.

[0132]

[0132] Compressing the sprayed metal coating by rotating the monopile 301 using the roller supports 302-305 may lead to changes in the structure of the sprayed metal coating. As noted above, the compressing is a result of the weight of the monopile and the position of the roller supports. In fact, the compressive stress is determined by the diameter of the monopile. For example, the compression may reduce the thickness and / or porosity of the sprayed metal coating. Furthermore, the compression may change the visual appearance of the sprayed metal coating. For example, after compression, the coating may include a surface with a smooth, shiny and uniform appearance without cracks, laminations, lumps or other visible defects. Other changes in structure, visual appearance or other properties are also possible due to compression.

[0133]

[0133] An advantage of applying pressure by rotating the monopile 301 is that the weight of the monopile 301 on the roller supports 302-305 causes sufficient pressure to compress the sprayed metal coating. This allows a particularly efficient way of applying pressure to compress the sprayed metal coating. It is noted, however, that different ways of compressing the sprayed metal coating are also possible. For example, the pressure may be applied via rollers different from the roller supports. Additionally or alternatively, the pressure may be applied via a press, for example a mechanical press or a hydraulic press. Alternative ways of applying pressure may be used to obtain a compressed sprayed metal coating on surfaces other than the circumferential outer surface of the monopile.

[0134]

[0134] FIG. 8 illustrates a schematic of a monopile according to an aspect of the present disclosure.

[0135]

[0135] The exterior surface of the monopile 301 may be completely coated. Different parts of the exterior surface of the monopile 301 may be coated using the same or different coating systems.

[0136]

[0136] For example, portions 501 and 502 may be coated with a compressed, thermally sprayed metal coating. Portions 801, 802, 803 may be coated with a compressed, thermally sprayed metal coating or one or more other coatings.

[0137] For example, portions 501 and 502 may be coated with a compressed sprayed metal coating. Portions where the sprayed metal coating is applied wider than the roller width, in this case portions 501 and 502, may be partially coated with a compressed sprayed metal coating and partially coated with a non-compressed sprayed metal coating, where the compressed sprayed metal coating forms a band within portions 501 and 502, where the band has a width equal to the width of the roller support used to compress the coating. Portions 801, 802, 803 may be coated using an epoxy coating and / or a non-compressed sprayed metal coating and / or a compressed metal coating. Portions 801, 802, 803 may be coated with the same or different coatings, and within a particular portion, multiple different coatings may be used. The multiple different coatings may be overlapping or non-overlapping.

[0138]

[0138] For example, the monopile 301 may be coated by applying sprayed metal to the portions 501 and 502 and rotating the monopile to compress at least a portion of the sprayed metal in the portions 501 and 502, and then the other portions 801, 802, 803 of the monopile may be coated using an epoxy coating. For example, one, two, three or more layers of epoxy coating may be applied to the monopile. It is possible to rotate the monopile 301 while applying the epoxy coating, which allows for efficient application of the epoxy coating. For practical reasons, for example, to ensure that the monopile is completely coated, the epoxy coating may be applied over at least some of the uncompressed sprayed metal coating that may be present in the portions 501 and 502. Although the epoxy coating could be applied over the compressed sprayed metal coating present in the portions 501 and 502, any epoxy coating that comes into contact with at least one of the roller supports 302-305 would be damaged. Therefore, when the coating method is performed while the monopile is rotating, no epoxy coating remains on the portions of the monopile that are in contact with the roller supports 302-305. Applying sprayed metal to portions 501 and 502, rotating the monopile to compress at least a portion of the sprayed metal in portions 501 and 502, and then applying one, two, three or more layers of epoxy coating to other portions 801, 802, 803 of the monopile 301 is a cost-effective way of coating the monopile. This coating method is cost-effective because the monopile 301 may be rotated during coating to allow automation of the coating method. Since a large portion of the monopile is coated with the epoxy coating, the method may be cost-effective because the epoxy coating may be less expensive than the sprayed metal coating.

[0139]

[0139] For example, the monopile 301 may be coated by applying a sprayed metal to the entire external surface. During the application of the sprayed metal, the roller supports 302-305 may be used to rotate the monopile 301. After the coating method, the parts of the external surface of the monopile 301 that correspond to the positions of the roller supports 302-305 during the coating method are coated with the compressed sprayed metal, while other parts of the external surface of the monopile 301 are coated with the uncompressed sprayed metal. In this way, the use of only one material may be required to coat the monopile 301, which may contribute to the automation of the coating method. The monopile 301 may be coated particularly quickly in this way, since it may be sufficient to apply only one coating, and also because the sprayed metal solidifies quickly, in contrast to, for example, epoxy coatings, and may need to be applied in several layers, with drying time of up to 24 hours between the application of the layers.

[0140]

[0140] For example, the monopile 301 may be coated by applying a sprayed metal to essentially the entire external surface and compressing the sprayed metal coating. For this purpose, the monopile 301 may be rotated a number of times, after which the monopile 301 and / or the roller supports 302-305 may be moved so that pressure can be applied to parts of the sprayed metal coating that are not yet compressed. By moving the monopile 301 and / or the roller supports 302-305, most or even the entire external surface may be coated with a compressed sprayed metal coating. In this way, a monopile 301 may be obtained which includes, in particular, a corrosion-resistant coating.

[0141]

[0141] It should be emphasized that the monopile 301 may be coated in different ways and compressed sprayed metal coatings, uncompressed sprayed metal coatings, epoxy coatings and other coatings and any combinations thereof may be applied to any portion of the monopile 301. One, two, three or more layers of any coating or combination of coatings may be applied to any portion of the monopile 301. The choice of coating may be dictated by practical considerations.

[0142]

[0142] Practical considerations that may influence the selection of a coating may include, but are not limited to, for example, the cost and / or time required to apply the coating, and / or the time required for the coating to dry, and / or the need to support the monopile 301 during coating, and / or whether the coating provides cathodic protection, and / or the need for the coating to be highly visible, and / or other considerations.

[0143]

[0143] Preferably, in the coating method the roller supports 302-305 are arranged such that the roller positions coincide with those parts of the monopile 301 where a compacted sprayed metal coating is desired or at least tolerated. Preferably, in the coating method the roller supports 302-305 are arranged such that the roller positions do not coincide with those parts of the monopile 301 where a coating different from a compacted sprayed metal coating is desired, for example an epoxy coating or a non-compacted sprayed metal coating is desired. If such an approach of the roller supports 302-305 is possible the coating method may be fully automated.

[0144]

[0144] Figure 9A and 9B are schematic diagrams illustrating the structure of a thermal sprayed metal coating prior to compressing the thermal sprayed metal coating according to an embodiment of the present disclosure, and after compressing the thermal sprayed metal coating according to an embodiment of the present disclosure.

[0145]

[0145] Thermally sprayed metal coatings are applied by jetting molten droplets of the coating material onto a surface. The molten droplets may be dispersed before the coating solidifies. After solidification, the thermally sprayed metal coating may have a structure comprising platelets of the coating material, where the platelets may be randomly oriented. Such a structure may be porous and ductile due to the random orientation of the platelets.

[0146]

[0146] Compression of the sprayed metal coating may change the structure of the coating. Under pressure, the platelets may align along a direction perpendicular to the pressure. This alignment reduces the open space between the platelets. This may reduce the thickness of the coating and may cause a decrease in porosity and ductility. To achieve these effects, a sufficiently large compressive stress should be applied. For example, such a sufficiently large compressive stress may be applied by a roller due to the weight of the monopile. In fact, the pressure between the roller and the monopile surface is determined by the diameter of the monopile. These effects may already be achieved by applying a sufficiently large compressive stress once, but it is also possible to apply a large compressive stress multiple times.

[0147]

[0147] An experiment was conducted to examine the reduction in porosity due to compression. Seven samples of TSA coated steel substrate and nine samples of TSZA coated steel substrate were prepared by tack welding the samples to a monopile surface and compressing the samples by rotating the monopile.

[0148] In detail, the samples were tack welded to a monopile with a length of 73 m, a diameter of 8 m and a wall thickness of 62 mm. The method described with reference to FIG. 2 was then applied. The monopile was placed on a roller support, so that the sample was in contact with the roller support during rolling. Blast cleaning was performed in different ways. For example, both manual and automatic blast cleaning was performed, and both steel and mineral grit abrasives were used. However, it was found that the way in which the blast cleaning was performed had no significant effect on the experimental results. In the experiment, only blast cleaning and applying a thermally sprayed coating were applied to the samples. No protective material was applied to the coating. The samples were compressed by rotating the monopile at least 25 times. However, no further visual changes of the samples were observed after the first compression. No sealant or further coating was applied to the samples. After compression, the samples were removed from the monopile for further analysis as described below.

[0149]

[0149] Samples were mounted and polished according to ASTM E1920-03 (2014) Standard Guide for Metallographic Preparation of Thermal Spray Coatings. Sections for porosity measurements were positioned on the more reflective parts of each sample (corresponding to the areas of greatest compression), and where sample curvature was evident, the sections were positioned parallel to the curvature.

[0150] For each sample, 20 images of each section were captured for porosity measurement. Images were captured using optical microscopy at a magnification suitable for porosity measurement. Porosity measurements were performed using a method conforming to ASTM E2109:2007.

[0151] All of the measured porosity values ​​are significantly below what would be expected for an uncompressed thermal sprayed metal coating. For uncompressed TSA or uncompressed TSZA, typical porosities are 5% to 15%. The measured porosities for the samples are provided below.

[0152]

[0152]

[0153] [Table 1]

[0154]

[0153] Optical micrograph examples of some samples are shown below in Figures 10A and 10B. For comparison, Figure 10C shows a typical thermal spray coating without compression. Figure 10A shows a TSA coating after compression. Figure 10B shows a TSZA coating after compression. For comparison, Figure 10C shows an uncompressed TSA coating. For all coatings shown in Figures 10A-10C, arc spraying was used as the thermal spraying technique. From a comparison of Figures 10A and 10B with Figure 10C, it can be seen that the compressed coating shown in Figures 10A and 10B has a smoother surface and reduced porosity compared to the uncompressed TSA coating shown in Figure 10C.

[0155]

[0154] It should be noted that the lower porosity of the coating may enhance its corrosion protection properties and / or provide other benefits.

[0156]

[0155] After compression, the visual characteristics of the sprayed metal coating may differ from the visual characteristics of the sprayed metal coating before compression. In particular, after compression, the coating may include a surface having a smooth, shiny and uniform appearance, free of cracks, laminations, lumps or other visible defects.

[0157]

[0156] Surprisingly, compression of a thermally sprayed metal coating may not significantly reduce the adhesion of the coating. Coatings that are relatively non-porous and well-adherent may be particularly suitable for corrosion protection.

[0158] Additionally or alternatively, the compression of the thermally sprayed metal coating may have further and / or other effects. The compression of the thermally sprayed metal coating and / or any further and / or any other effects realized thereby may achieve at least some of the benefits described above or may achieve other benefits.

[0159]

[0158] In the foregoing description of the drawings, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and changes may be made without departing from the scope of the invention as outlined in the appended claims.

[0160] In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from essential scope thereof. Therefore, it is not intended that the invention be limited to the particular embodiments disclosed, but the invention will include all embodiments falling within the scope of the appended claims.

[0161]

[0160] In particular, combinations of specific features of the various aspects of the invention may be made. An aspect of the invention may be further advantageously enhanced by the addition of features that have been described in relation to another aspect of the invention.

[0162]

[0161] It is to be understood that the present invention is limited only by the appended claims. In this document and in the claims, the verb "comprise" and its conjugations are used in their open-ended sense, meaning that the items following the word are included, without excluding items not specifically mentioned. In addition, reference to an element by the indefinite article "a" or "an" does not exclude the possibility that there is more than one of that element, unless the context clearly requires that there is only one such element. Thus, the indefinite article "a" or "an" usually means "at least one."

Claims

1. Placing a monopile having a diameter of 8 m or more on a roller support, wherein the roller support is provided with rotating means for rotating the monopile when the monopile is placed on the roller support, the rollers support the monopile, and when the monopile is placed on the roller support, it is positioned at one or more positions along the axis of the monopile, the placing; Generating pressure at the contact point between the roller support and the monopile, wherein the pressure is based on the weight of the monopile on the roller support, the generating; Applying a sprayed metal coating, such as an aluminum or zinc-aluminum coating, to a portion of the outer circumferential surface of the monopile corresponding to the one or more positions; Compressing at least a part of the sprayed metal coating by rotating the monopile using the roller support, wherein the compression structurally changes the sprayed metal coating, the compressing; A monopile coating method comprising the above.

2. Compressing at least a part of the sprayed metal coating comprises compressing the sprayed metal coating such that the thickness of the coating is reduced by 15% to 80%, preferably 20% to 70%, more preferably 25% to 60%, and most preferably 30% to 50%. The monopile coating method according to Claim 1.

3. Compressing at least a part of the sprayed metal coating comprises rotating the monopile at least 10, preferably at least 20, more preferably at least 25, and most preferably at least 30 times on average. The monopile coating method according to Claim 1.

4. After applying the sprayed metal coating and before or during compressing at least a part of the sprayed metal coating, further comprising applying a protective material, such as a polymer foam or a rubber sheet, on the sprayed metal coating. The monopile coating method according to Claim 1.

5. The monopile coating method according to claim 1, further comprising applying a sealer onto the sprayed metal coating after compressing at least a part of the sprayed metal coating.

6. The monopile coating method according to claim 1, further comprising applying a further coating onto the sprayed metal coating after compressing at least a part of the sprayed metal coating.

7. The monopile coating method according to claim 1, wherein the portion of the circumferential outer surface of the monopile corresponding to the one or more positions has a width that varies from 0.2 m to 3 m, preferably from 0.4 m to 2.5 m, more preferably from 0.5 m to 2 m, and most preferably from 0.7 m to 1.5 m, based on the type of roller support used.

8. The monopile coating method according to claim 7, wherein the width of the portion of the circumferential outer surface of the monopile corresponding to the one or more positions is the same as or greater than the width of the roller support.

9. The monopile coating method according to claim 1, wherein during the compressing, the compression stress on the sprayed metal coating at the contact point exceeds 500 MPa, preferably 750 MPa, more preferably 1 GPa, and most preferably 1.5 GPa.

10. The monopile coating method according to claim 1, wherein the monopile includes a longitudinal submerged arc weld, and the monopile coating method further comprises ground flashing the longitudinal submerged arc weld before placing the monopile on the roller support.

11. The monopile coating method according to claim 1, further comprising blast cleaning the portion of the circumferential outer surface of the monopile corresponding to the one or more positions before applying the sprayed metal coating.

12. The monopile coating method according to claim 11, wherein the blast cleaning is preferably carried out using open jet grit blasting with a steel or mineral grit abrasive, or preferably using automatic turbine blast cleaning with a steel grit abrasive.

13. The method for monopile coating according to claim 11, wherein the blast cleaning includes pretreating the surface so as to have an acute profile depth within a range of 40 μm to 150 μm, preferably 50 μm to 125 μm, more preferably 60 μm to 115 μm, and most preferably 80 μm to 105 μm.

14. A monopile coated using the monopile coating method according to any one of claims 1 to 13.

15. A monopile coating system including a roller support and a spraying device, wherein the roller support is provided with rotating means for rotating the monopile when a monopile having a diameter of at least 8 m is placed on the roller support, the roller is for supporting the monopile, and is positioned at one or more positions along the axis for placing the monopile on the roller support, and the spraying device is configured to apply a sprayed metal coating, such as an aluminum or zinc-aluminum coating, to a portion of the outer circumferential surface of the monopile corresponding to the one or more positions.

16. The monopile coating system according to claim 15, further configured to perform the monopile coating method according to any one of claims 2 to 13.

17. Applying a sprayed metal coating, such as an aluminum or zinc-aluminum coating, to the surface of an object; Generating pressure at a contact point between the object and a further object, wherein the object is on the further object and the pressure is based on the weight of the object on the further object; Compressing the sprayed metal coating by the pressure, wherein during the compressing, the compressive stress on the sprayed metal coating at the contact point exceeds 500 MPa, preferably 750 MPa, more preferably 1 GPa, and most preferably 1.5 GPa, and the compression structurally changes the sprayed metal coating. A coating method comprising:

18. Compressing the sprayed metal coating comprises reducing the thickness of the coating by 15% to 80%, preferably by 20% to 70%, more preferably by 25% to 60%, and most preferably by 30% to 50%. The coating method according to claim 17.

19. After applying the sprayed metal coating and before or during compressing the sprayed metal coating, further comprising applying a protective material, such as a polymer foam or a rubber sheet, onto the sprayed metal coating. The coating method according to claim 17.

20. After compressing the sprayed metal coating, further comprising applying a sealer onto the sprayed metal coating. The coating method according to claim 17.

21. After compressing the sprayed metal coating, further comprising applying a further coating onto the sprayed metal coating. The coating method according to claim 17.

22. Before applying the sprayed metal coating, further comprising blast cleaning the surface. The coating method according to claim 17.

23. The blast cleaning is preferably carried out using open jet grit blasting with steel or mineral grit abrasive, or preferably using automatic turbine blast cleaning with steel grit abrasive. The coating method according to claim 22.

24. The blast cleaning comprises pretreating the surface such that it has an acute profile depth in the range of 40 μm to 150 μm, preferably 50 μm to 125 μm, more preferably 60 μm to 115 μm, and most preferably 80 μm to 105 μm. The coating method according to claim 22.

25. A coating obtainable by using the monopile coating method according to any one of claims 1 to 13, obtained and / or directly obtained, or obtainable by using the coating method according to any one of claims 17 to 24, obtained and / or directly obtained. Claim 26 The coating according to claim 25, which is used on the surface of a monopile. Claim 27 A coating system comprising spraying equipment and means for compressing a sprayed metal coating, wherein the spraying equipment is configured to apply a sprayed metal coating, such as an aluminum or zinc-aluminum coating, to a surface, and the means for compressing the sprayed metal coating is configured to compress the sprayed metal coating such that the compressive stress on the sprayed metal coating at the contact points exceeds 500 MPa, preferably 750 MPa, more preferably 1 GPa, and most preferably 1.5 GPa. Claim 28 The coating system according to claim 27, further configured to perform the monopile coating method according to any one of claims 18 to 24.

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