Cathodic protection device for use in an impressed current cathodic protection system

Abstract

The present invention relates to a cathodic protection device for use in an impressed current cathodic protection system for marine structures. The device comprises a spacer tube, a flange, and a tubular anode. According to the present invention, the tubular anode axis coincides with the spacer tube axis of the spacer tube, and the anode radius is at most 1.35 times the spacer tube radius. When the tubular anode is provided in an anode housing attached to the spacer tube, the housing radius is at most 1.35 times the spacer tube radius. Thus, the cathodic protection device has a linear configuration to enable a flexible object to slide along the spacer tube from the spacer tube to the anode or anode housing, across the anode or anode housing, and away from the anode or anode housing without getting stuck.

Description

Technical Field

[0001] The present invention relates to a cathodic protection device for use in an impressed current cathodic protection (ICCP) system for providing cathodic protection to marine structures, preferably to wind turbine foundations such as wind turbine foundation piles.

Background Art

[0002] It is known to provide an ICCP system to marine structures in order to provide cathodic protection to a structure, and by extension, to prevent or at least slow down the corrosion of the structure.

[0003] For example, an offshore wind turbine is supported by a steel structure in the form of a foundation pile and a jacket-like structure. To protect these structures against corrosion, an ICCP system is provided to the structures. An excellent benefit of the ICCP system over conventional protection systems that utilize sacrificial anodes is that, with an ICCP system, the anodes can be used for a relatively long period of time.

[0004] An ICCP system typically comprises a control device, a power source, one or more anodes, and one or more reference cells. The power source is connected to the structure to be protected and the anode in order to create a potential difference. One or more reference cells monitor the potential difference created by the ICCP system, and the control system controls the power source based on the information provided by the one or more reference cells.

[0005] Materials used for the anodes are, for example, high silicon cast iron, graphite, mixed metal oxide (MMO), platinum, and wire coated with niobium.

[0006] Anodes for ICCP systems are available in various shapes and sizes. Common anodes are disk-shaped and rod-shaped and are attached to a spacer frame or tube to set the anode at a distance from the surface to be protected. The disk-shaped anode is supported by a spacer tube such that the anode surface faces away from the structure and away from the spacer frame or tube. When viewed from the side, the disk-shaped anode has a T-shaped configuration. The rod-shaped anode is typically provided by two or more anodes supported by a single spacer frame or tube. The tube or spacer frame branches into a plurality of branches, each of which supports an anode. Such a cathodic protection device may have, for example, a T-shape or a Y-shape.

[0007] Patent Document 1 discloses two tubular anodes supported by a spacer frame welded to a foundation pile. The anodes are set parallel to each other and parallel to the longitudinal axis of the wind turbine foundation pile. Patent Document 2 discloses a rod-shaped anode set at the end of a mooring structure. Here too, two anodes set parallel to each other are provided. In both Patent Document 1 and Patent Document 2, the anodes extend in a direction perpendicular to the support frame, providing a cathodic protection device with a T-shaped configuration. Patent Document 3 discloses an ICCP system with a disk-shaped anode. The disk-shaped anode is supported at the end of a spacer tube, providing a cathodic protection device with a T-shaped configuration.

[0008] It has been proposed that the configuration of prior art anodes tends to cause the anodes to catch freely floating objects such as ropes, nets, and plastic sheets. These objects can get caught behind the anodes and the spacer structures that support the anodes. These objects can potentially prevent the cathode protection device from functioning. Further, when an object gets caught behind the cathode protection device, this increases the flow resistance of the cathode protection device. This is particularly detrimental when the cathode protection device is mounted near the splash zone, and wave movement, in addition to water flow, further increases the load on the caught object and, by extension, further increases the load on the anode and the spacer frame to which the anode is mounted. The increased load can potentially cause damage to the anode and / or the spacer frame, for example, it can potentially bend or break the spacer frame.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] It is an object of the present invention to provide an improved cathodic protection device for use in an impressed current cathodic protection (ICCP) system for providing cathodic protection to marine structures, preferably to wind turbine foundations such as wind turbine foundation piles. The present invention further aims to provide a more effective ICCP system, more specifically, a cathodic protection device that enables a system that is less susceptible to disturbances caused by foreign objects. The present invention further aims to provide a cathodic protection device that enables a more efficient manufacturing process. **Means for Solving the Problems**

[0011] Therefore, the present invention provides a cathodic protection device for use in an impressed current cathodic protection system (ICCP system) for providing cathodic protection to marine structures such as wind turbine foundation piles according to claim 1.

[0012] It has been found that an object that becomes immovable in the anode and / or the spacer frame that supports the anode hinders the function of the anode. Specifically, the object interferes with the field generated by the anode, which may reduce the corrosion protection provided by the anode. Therefore, the cathodic protection device according to the present invention enables a more effective ICCP system.

[0013] The present invention provides a more efficient design of the cathodic protection device, specifically, a more efficient design in the way the spacer tube and the anode are set up relative to each other. By providing a tubular anode extending parallel to the straight spacer tube in combination with an anode radius that is 1.35 times or less the radius of the spacer tube, floating objects are held with reduced grip on the anode and the spacer tube. Therefore, the possibility that foreign objects become immovable in the cathodic protection device and interfere with the field generated by the anode is reduced.

[0014] Furthermore, by combining the tubular anode with the spacer tube, the design of the spacer tube can be made more efficient, i.e., it does not need to be as robust. Potentially, a lighter spacer tube can be used due to its lower cost compared to prior art spacer frames. Therefore, the present invention also enables the efficient use of synthetic materials to form the spacer tube.

[0015] It is proposed that the anode of the cathode corrosion protection device according to the present invention is oriented in a direction substantially parallel to the surface to be protected. In the prior art, at least a part of the anode is oriented away from the surface to be fabricated. It is known that the cathode corrosion protection device according to claim 1 can provide a suitable corrosion protection area.

[0016] The cathode corrosion protection device according to claim 1 - a spacer tube having an outward-facing spacer tube surface extending along a linear spacer tube axis between a foot end and a head end of the spacer tube, and having a spacer tube radius extending between the spacer tube axis and the spacer tube surface; - a flange having a mounting surface for mounting the cathode corrosion protection device to a mounting surface of a mounting portion of a marine structure, and being connected to the spacer tube at the foot end of the spacer tube; - a tubular anode having an outward-facing anode surface extending along a linear anode axis between a foot end and a head end of the tubular anode, and having an anode radius extending between the anode axis and the anode surface; comprising The tubular anode is mounted to the spacer tube at the head end of the spacer tube with the tubular anode axis coinciding with the spacer tube axis of the spacer tube, and a flexible object can slide along the spacer tube from the foot end to the head end, and can slide from the spacer tube, onto the anode, across the anode, and away from the anode, and the anode radius is at most 1.35 times the spacer tube radius.

[0017] The cathodic protection device according to the present invention is specifically useful for the corrosion protection of foundation piles and transition parts used to support offshore wind turbines. Foundations of these types typically have a cylindrical configuration. Prior art anodes attached to such structures are typically supported by a spacer frame to set the anode at a distance from the object. The object can be easily immobilized in the spacer frame and anode projecting outward from the structure. However, the cathodic protection device according to the present invention provides minimal gripping of foreign objects and is configured to prevent the object from becoming immobilized after the cathodic protection device.

[0018] According to the present invention, the cathodic protection device comprises a spacer tube that sets a tubular anode at a distance from the object to be protected, and the tubular anode is attached to the spacer tube with the anode axis parallel to the spacer tube axis of the spacer tube. Thus, the tubular anode extends in the longitudinal direction of the spacer tube. Since the anode radius is at most 1.35 times the spacer tube radius, the anode does not extend significantly beyond the radius of the spacer tube. Therefore, the cathodic protection device, more specifically, the combined spacer tube and anode, is substantially rod-shaped. Thus, an object caught around the spacer tube can slide along the spacer tube and slip off the end of the cathodic protection device without becoming immobilized after a branch of the spacer tube, anode, or anode housing.

[0019] In an embodiment, the anode surface is recessed with respect to the outer surface of the spacer tube, that is, the anode radius is smaller than the spacer tube radius, and one or more guide rails extending parallel to the anode axis along the anode are provided. The one or more guide rails preferably extend parallel to the spacer tube axis, and each of the guide rails has an outward-facing guide surface that is similar to the outer periphery of the spacer tube at the head end of the spacer tube. In such an embodiment, the object is urged to slide from the spacer tube to the guide rail and thus along the anode.

[0020] In an embodiment of the cathode corrosion protection device according to the present invention, the tubular anode is received in the anode housing, and the anode housing is an anode cover such as a net or one or more guide rails, having an outward-facing guide surface extending parallel to the anode surface for guiding an object across the anode surface. The anode housing has a housing radius extending between the anode axis and the guide surface, and the housing radius is at most 1.35 times the spacer tube radius.

[0021] In a further embodiment, the anode housing further comprises a base at the foot end of the housing and an upper part at the head end of the housing. The cover extends between the base and the upper part. The anode housing is mounted by the base across the head end of the spacer tube. The base and the upper part of the anode housing each have an outward-facing surface, and the outward-facing surfaces of the base and the upper part are flush with the guide surface of the cover. Thus, the anode housing has a non-protruding outer surface, and a flexible object can slide onto and off the anode housing without getting stuck.

[0022] In a further embodiment, the base of the housing is conical to facilitate an object sliding along the spacer tube onto and across the tubular anode, providing an inclination between the spacer tube surface and the guide surface of the cover.

[0023] In an embodiment, the anode is received in the anode housing, and the anode housing comprises one or more guide rails extending parallel to the anode axis along the anode. The one or more guide rails preferably extend parallel to the anode axis, and each of the guide rails has an outward-facing guide surface similar to the outer circumference of the spacer tube at the head end of the spacer tube. Thus, the guide surfaces of the one or more guide rails have a radius similar to the spacer tube radius, forming a continuation of the surface of the spacer tube. Thus, an object can easily slide from the spacer tube onto the guide rails and out of the cathode corrosion protection device.

[0024] In an embodiment, when viewed in the direction from the foot end to the head end, the spacer tube has an outer surface without protrusions. The spacer tube has a continuous cross-section along its longitudinal axis. In combination with a tubular anode set coaxially therewith, this further prevents an object from becoming immobile in the cathodic protection device.

[0025] In an embodiment, the tubular anode is mounted across the spacer tube near the head end of the spacer tube such that the anode surface is flush with the spacer tube surface facing outward of the spacer tube or is recessed with respect to the spacer tube surface, or is provided in an anode housing mounted to the spacer tube at the head end of the spacer tube. The housing has an outer surface that is flush with the outer surface of the spacer tube such that a flexible object can slide along the spacer tube from the foot end to the head end without being caught after a protrusion extending from the spacer tube, anode, or anode housing, and can slide from the spacer tube to the anode or anode housing, across the anode or anode housing, and away from the anode or anode housing. In such an embodiment, the anode radius is preferably at most the same as the spacer tube radius, i.e., at most 1 times the spacer tube radius, or when the anode is received in the anode housing, the housing radius is at most the same as the spacer tube radius, i.e., at most 1 times the spacer tube radius.

[0026] In an embodiment, the length of the spacer tube is in the range of 120 to 160 cm, and the length of the tubular anode is in the range of 40 to 60 cm. In an embodiment, the length of the spacer tube is at least 2.5 times the length of the tubular anode housing. For example, the length of the spacer tube is about 3 times the length of the tubular anode housing.

[0027] In an embodiment, the spacer tube radius is in the range of 17 to 20 cm, and the anode radius or housing radius is in the range of 22 to 27 cm. When the tubular anode is received in the anode housing, it is proposed that the anode radius be smaller than the housing radius. In an embodiment, the anode radius is smaller than the spacer tube radius, and the housing radius is at most the spacer tube radius.

[0028] When a coating having a surface facing outward is provided on the spacer tube, it is proposed that the surface facing outward of the coating is understood to also be the surface of the spacer tube facing outward here.

[0029] In a preferred embodiment, when the spacer tube is attached to the building to be protected, it has an upward-facing surface that slopes horizontally and downward, that is, an upward-facing surface as seen in a plane perpendicular to the longitudinal axis of the spacer tube. Thus, gravity can cause an object that has fallen onto the upper surface to slide off the spacer tube. In the embodiment, the cross-section is rectangular or triangular, and one point of each rectangle or triangle forms the vertex of the cross-section.

[0030] In a preferred embodiment, the spacer tube has a circular cross-section. Thus, for example, an object that is horizontally pushed against the side surface of the spacer tube by an ocean current can also easily slide off the spacer tube.

[0031] In the embodiment, the spacer tube axis of the spacer tube is provided at the center of the cross-section of the spacer tube. Thus, the cross-sections are aligned in a row with respect to each other at the spacer tube axis.

[0032] The flange of the cathodic protection device according to the present invention has a mounting surface for mounting the cathodic protection device on the mounting surface of the mounting part of the marine structure. Thus, the cathodic protection device is fixed to the mounting surface of the mounting part in the marine structure at the mounting surface of the flange. Typically, the protected structure such as a transition part or a foundation pile that supports a wind turbine is provided with a mounting part having a flange with a mounting surface similar to the mounting surface of the flange of the cathodic protection device. In such an embodiment, the cathodic protection device is bolted to the flange of the mounting part in the protected structure with its flange.

[0033] The flange of the cathodic protection device is connected to the spacer tube at the foot end of the spacer tube. Thus, the flange protrudes outward with respect to the spacer tube. Preferably, the flange is provided with a smooth transition part such as chamfering between the spacer tube and the flange.

[0034] In an embodiment, the cathode corrosion protection device includes a tubular anode having a continuous or semi - continuous anode surface that extends 360 degrees around the anode axis in parallel with the anode axis.

[0035] In an embodiment, the cross - sectional shape of the tubular anode is the same as the cross - sectional shape of the spacer tube, for example, both have an octagonal cross - section. In a preferred embodiment, both the spacer tube and the anode have a circular cross - section.

[0036] The tubular anode has an anode axis and an anode surface. The anode surface is cylindrically arranged around the anode axis so as to be parallel to the central anode axis and to face away from the central anode axis. The tubular anode is attached to the spacer tube at the head end of the tubular anode in a state where the central tubular anode axis is parallel to the spacer tube axis of the spacer tube and is aligned with the spacer tube axis.

[0037] In an embodiment of the cathode corrosion protection device according to the present invention, the cross - section of the anode is the same as the cross - section of the spacer tube at the head end of the spacer tube, or is positioned within the cross - section of the spacer tube and has an anode axis that is aligned with the spacer tube axis. Thus, the flexible object can slide along the spacer tube from the foot end to the head end without being caught after a protrusion extending from the spacer tube or the anode, and can slide from the spacer tube, to the anode, across the anode, and away from the anode.

[0038] In an embodiment, the anode extends between a foot end and a head end, and the cross-section of the anode at the foot end is the same as the cross-section of the spacer tube at the head end of the spacer tube. In such an embodiment, the tubular anode forms a continuation of the spacer tube. More specifically, the spacer tube and the tubular anode have a continuous cross-section when viewed along the spacer tube axis in the direction from the foot end to the head end, and the surface of the tubular anode forms a continuation of the outer surface of the spacer tube. That is, at the transition from the outer surface of the spacer tube to the outer surface of the tubular anode, there is no significant depression, recession, or protrusion. The continuous cross-section, and by extension the continuous smooth outer surface, makes it more difficult for an object to be gripped and immobilized in the spacer tube.

[0039] In an embodiment, the anode housing is attached to the spacer tube such that the head end of the spacer tube is received inside the foot end of the anode housing. In such an embodiment, the foot end of the anode housing is preferably provided with a gradual increase in its cross-section. Thus, the anode housing provides an inclination, that is, a gradual transition between the spacer tube surface at the spacer tube radius and the guide surface of the anode cover at the housing radius. This further facilitates the sliding of an article along the length of the spacer tube onto, across, and off the anode housing.

[0040] In an embodiment, the spacer tube axis of the spacer tube is provided at the center of the cross-section of the spacer tube. Thus, the cross-sections are aligned with each other in a row at the spacer tube axis.

[0041] In an embodiment, the tubular anode extends longitudinally between a foot end and a head end, and the tubular anode has a continuous cross-section when viewed in the direction from the foot end to the head end.

[0042] In an embodiment, the anode surface is recessed with respect to the outer surface of the spacer tube, and a net extending parallel to the anode axis along the anode surface is provided. The net allows a flexible object to slide along the spacer tube from the foot end to the head end, and from the spacer tube to the net, and further to slide out of the anode without getting caught after a protrusion extending from the spacer tube or the net. To this end, the spacer tube and the net form a guiding surface without continuous protrusions, and have a guiding surface facing outward that is flush with the surface of the spacer tube.

[0043] Therefore, in such an embodiment, the guiding net has an outer circumference that is the same as the outer circumference of the spacer tube at the head end of the spacer tube, and the outer surface of the net forms a continuation of the outer surface of the spacer tube. Further, the spacer tube, the guiding net, and the anode extend along a single straight axis.

[0044] In another embodiment, the anode surface is recessed with respect to the outer surface of the spacer tube, and one or more guiding rails extending parallel to the anode axis along the anode surface are provided. Each of the one or more guiding rails allows a flexible object to slide along the spacer tube from the foot end to the head end, and from the spacer tube to the guiding rail, and further to slide out of the anode without getting caught after a protrusion extending from the spacer tube or the guiding rail. To this end, the spacer tube and the guiding surfaces of the one or more guiding rails form a guiding surface without continuous protrusions, and have a guiding surface facing outward that is flush with the surface of the spacer tube. Therefore, in such an embodiment, the one or more guiding rails have an outer circumference that is the same as the outer circumference of the spacer tube at the head end of the spacer tube, and the guiding surfaces of the one or more rails form a continuation of the outer surface of the spacer tube. Further, the spacer tube, the guiding rails, and the anode extend along a single straight axis. Therefore, in such an embodiment, the guiding surfaces of the one or more guiding rails are aligned with the outer circumference, i.e., the outer surface, of the spacer tube at the head end of the spacer tube, and the guiding surfaces of the one or more guiding rails form a continuation of the outer surface of the spacer tube.

[0045] In some embodiments, the mesh or one or more guide rails extend along the anode, while the anode surface is positioned recessed relative to the outer surface of the mesh or the outer surface of the one or more guide rails. Thus, the mesh or guide rails form a guide surface for an object sliding over the tubular anode and, by extension, protect the anode surface from being damaged, etc. In these embodiments, the radius between the guide surface of the guide rail or the mesh and the anode axis is the housing radius. Thus, the guide surface of the guide rail or the mesh is at most 1.35 times the spacer tube radius.

[0046] In an embodiment, one or more guide rails extend parallel to the spacer tube axis. In such an embodiment, the edges of the guide rails extend parallel to the longitudinal axis of the spacer tube and the anode axis, thus further reducing the possibility that an object sliding in the longitudinal direction of the cathodic protection device will become immobile.

[0047] When the cathodic protection device is attached to an offshore structure, the cross-section of the spacer tube has a highest point at the head end at the 12 o'clock position and a lowest point of the cross-section of the spacer tube at the 6 o'clock position. When one or more guide rails are provided along the tubular anode on the cathodic protection device, preferably, one of the one or more guide rails is positioned at the 12 o'clock position. Thus, an object sliding along the cathodic protection device slides from the surface of the spacer tube onto the guide surface of the guide rail and then slides off the cathodic protection device via the guide rail.

[0048] Alternatively or additionally, a guide rail can be provided at the 10 o'clock position and a guide rail is provided at the 2 o'clock position.

[0049] In an embodiment, the guide rail has a width such that the guide surface of the guide rail extends along at least 3 percent around the spacer tube, such as extending over an angle of at least 11 degrees.

[0050] When one guide rail is provided, the rail is preferably provided at the 12 o'clock position when the cathodic protection device is attached to the marine structure and has a relatively wide guide surface. In an embodiment, a single rail has a width such that the guide surface of the guide rail extends along at least 10% of the circumference, i.e., a width that extends over an angle of at least 36 degrees. Providing a wide guide surface on the guide rail enhances the protection of the anode surface. When a plurality of guide rails are provided, the guide rails can have relatively narrow guide surfaces and still prevent an object from damaging the anode surface.

[0051] In a further embodiment, one or more guide rails are part of the anode housing, and the anode housing further comprises a base at the foot end and an upper part at the head end of the housing, the guide rail extending between the base and the upper part, and the anode housing being attached to the spacer tube at the head end of the spacer tube by the base, the base of the anode housing having a cross-section that is preferably similar to the cross-section of the spacer tube at the head end of the spacer tube such that the outer surface of the housing forms a continuation of the outer surface of the spacer tube.

[0052] Thus, the anode housing protects the anode surface and a flexible object can slide along the spacer tube from the foot end to the head end without getting caught after a protrusion extending from the spacer tube or the anode housing, and can slide from the spacer tube to the anode housing, over the anode housing, and away from the anode housing.

[0053] In a further embodiment, the anode housing and the spacer tube are modular components that are combined to form a cathodic protection device. Such embodiments can provide spacer tubes of different lengths, such as an anode housing with one tubular anode and an anode housing with two or more tubular anodes, and these can be combined into a cathodic protection device configured for a specific object to be protected. For example, an ICCP system for a specific object may require the use of a long spacer tube, while an ICCP system for another object may require a short spacer tube. Thus, during the manufacturing process, the modular anode housing can be combined with a short spacer tube or a long spacer tube to fit each of the first ICCP system or the end ICCP system.

[0054] In an embodiment, the anode housing comprises a tubular anode support, and the anode material is a single sheet adhered to the anode support. This configuration enables efficient policies for the tubular anode. In a further embodiment, the anode support is configured to be attached to a base part and an upper part to form the anode housing. Alternatively, the base and / or the upper part may be an integral part of the anode support.

[0055] In an alternative embodiment, the tubular anode comprises a first anode element, and the first anode element is semi-cylindrical and extends, for example, over an arc of at least 90 degrees, preferably over an arc of about 180 degrees. In a further preferred embodiment, when the cathodic protection device is mounted on an offshore structure, the first anode element is oriented downward, i.e., provided on the side of the cathodic protection device facing the seabed.

[0056] Thus, the tubular anode is a modular tubular anode, and the anode comprises one or more modular anode elements. During the manufacturing process, the size of the anode can be determined by attaching one or more of the modular anode elements. For example, in an embodiment, the tubular anode can comprise one anode element, two anode elements, or three anode elements each extending over an arc of 120 degrees.

[0057] In a further embodiment, the tubular anode comprises a first anode element and a second anode element, the second anode element is also semi-cylindrical, the first anode element and the second anode element each extend over an arc of approximately 180 degrees, and when the cathodic protection device is attached to the marine structure, the second anode element is provided on the side of the cathodic protection device that faces upward, i.e., away from the seabed.

[0058] In an embodiment, the tubular anode comprises a plurality of anode elements. In such an embodiment, one of the anode elements is redundant and will only be used if one or more of the other anode elements fail. In an embodiment, the second anode element is used when the first anode element does not provide a strong enough field. In an alternative embodiment, both or all of the anode elements are operating during the use of the cathodic protection device.

[0059] In a further embodiment, the tubular anode comprises two or more anode elements, and the anode elements are separately powered such that if the power supply to one anode element, or to one of the anode elements, fails, at least one other anode element is still powered. Thus, the anode can still create a field even when part of the anode is no longer operating.

[0060] In an embodiment, the tubular anode is a first tubular anode, and the cathodic protection device is provided with a second tubular anode similar to the first tubular anode, and the second tubular anode is mounted coaxially with the first anode in a spacer tube, or the first and second anodes are mounted coaxially in a single anode housing according to the invention such that the anode axis of the second anode coincides with the anode axis of the first anode.

[0061] In an embodiment, the second tubular anode is redundant and is only used when the first tubular anode fails, or the second tubular anode is used when the first tubular anode does not provide a strong enough field. In an alternative embodiment, both anode elements are operating during the use of the cathodic protection device.

[0062] In a further embodiment, the tubular anode comprises two or more anode elements of anode material, and the anode elements are separately powered such that, in the event of a power failure of one anode element, or of one of the anode elements, at least one other anode ICCP element is still powered. Thus, the anode can still create a field even when a part of the anode is no longer operating.

[0063] In an embodiment, the spacer tube and at least a part of the anode housing are a single part, and the anode is mounted to a part of the anode housing that is an integral component with the spacer tube.

[0064] In a preferred embodiment, the spacer tube is hollow, and a cable for connecting the anode to a power source and / or a control unit is guided from the housing to the flange through the hollow spacer tube. For example, the flange may be provided with a recess on its guiding surface for guiding the cable from the inside to the outside of the spacer tube.

[0065] In an embodiment, the spacer tube is made of a metal such as steel, and a coating is provided to shield the spacer tube from the field generated by the anode. In such an embodiment, the coating has an outward-facing surface that is understood herein as the outward-facing spacer tube surface.

[0066] In an embodiment, the spacer tube is made of a synthetic material, preferably a fiber-reinforced synthetic material. Thus, the spacer tube is not conductive and does not need to be provided with a coating. Furthermore, for this reason, the spacer tube can be made of a relatively lightweight material, and the cathodic protection device can be kept lightweight. In a further embodiment, the cathodic protection device comprises an anode housing that is at least partially made of a synthetic material.

[0067] In a further embodiment, the flange is a separate component that is attached to the spacer tube during the manufacturing process. In a further embodiment, the flange is made of steel and the spacer tube is made of a synthetic material.

[0068] In an embodiment, the flange is connected to the spacer tube in a state where the mounting surface of the flange extends perpendicular to the spacer tube axis in the longitudinal direction of the spacer tube.

[0069] In a preferred embodiment, the flange extends at an angle with respect to the spacer tube axis of the spacer tube so that the cathodic protection device can be mounted on the marine structure at an angle with respect to the horizontal, that is, with a mounting surface of the flange extending at an angle in the range of 1 to 8 degrees, and is connected to the spacer tube. This configuration allows the cathodic protection device to be mounted on the structure with the spacer tube axis pointing downward, which facilitates the object to slide away from the flange and disengage from the cathodic protection device. Typically, it has been proposed that a dedicated mounting portion for attaching the cathodic protection device to the marine structure be provided, and the dedicated mounting portion has a mounting surface that is substantially vertical.

[0070] It is noted that in order to obtain the same effect in combination with a cathodic protection device having a mounting surface that is perpendicular to the spacer tube axis, the mounting portion on the structure to be protected can be set at a slight angle with respect to the vertical. However, in such a configuration, the mounting portion in the building protrudes more with respect to the surface of the structure, and thus creates a feature where foreign objects cannot move later. Therefore, by setting the spacer tube at an angle with respect to the mounting surface of the flange of the cathodic protection device, the mounting surface, and thus the flange of the mounting portion of the structure to be protected, can remain parallel to the surface of the structure to be protected and thus remain close to its surface.

[0071] In an embodiment, the flange is preferably an annular plate made of steel, and the annular plate has an inward-facing annular surface that is fixed to the outer surface of the spacer tube at the foot end of the spacer tube. Thus, a simple configuration of the flange is provided. In a further embodiment, the annular plate is along an opening provided with a wall feature to expand the annular surface attached to the spacer tube. In yet a further embodiment, this wall, or at least the inner surface of this wall, is configured such that the closed space, i.e., the space for receiving the spacer tube, is at an angle with respect to the mounting surface of the flange. Thus, the configuration provides a spacer tube that is set at an angle with respect to the mounting surface of the flange.

[0072] It is proposed that the flange may be provided with a central inner space for receiving the spacer tube. In such an embodiment, the outer surface of the spacer tube is mounted on the inward-facing surface of the flange. Alternatively, the wall feature along the inner opening of the annular plate is configured to be inserted into the spacer tube. In such an embodiment, the outward-facing wall surface is attached to the inward-facing surface of the hollow spacer tube.

[0073] In an embodiment, the cathodic protection device further comprises a reference cell and a reference cell support bracket, and the reference support bracket is configured to be mounted on the flange, preferably configured to be mounted between the flange and a dedicated mounting part of the marine structure. By providing the reference cell on the bracket mounted on the mounting surface, instead of the spacer tube, the reference cell can be mounted near the anode while the spacer tube can remain non-projecting.

[0074] In an embodiment, a reference cell attached to a spacer tube is provided in the cathode corrosion protection device. In such an embodiment, the reference cell is preferably provided near the flange of the cathode corrosion protection device such that most of the spacer tube, i.e., the area of the spacer tube between the reference cell and the tubular anode, has no protrusion. Thus, a flexible foreign object in contact with the spacer tube can still slide along most of the spacer tube, over the tubular anode, and across the annular anode without contacting the reference cell and, by extension, without the risk of becoming immobile behind the reference cell.

[0075] In an embodiment, the reference cell is provided on the bottom side of the cathode corrosion protection device, i.e., on the side facing the seabed during use, such that an object cannot easily get caught thereon later. Further, in this position, the reference cell or its support bracket can prevent an object from sliding along the spacer tube towards the housing of the cathode corrosion protection device.

[0076] The cathodic protection device according to the present invention is configured to reduce the possibility that an object becomes immovable in the cathodic protection device. Here, the flexible object refers to an object that at least partially follows the shape of the spacer tube and the anode contour, such as a plastic sheet, a discarded fishing net, a rope, etc. It has been found that an object that becomes immovable in the anode and / or the spacer frame supporting the anode hinders the function of the anode. Specifically, the object may reduce the cathodic protection provided by the anode by interfering with the field generated by the anode. Therefore, the cathodic protection device according to the present invention enables a more efficient ICCP system. Further, when an object is caught behind the cathodic protection device, this increases the flow resistance of the cathodic protection device. This is particularly harmful when the cathodic protection device is mounted near the splash zone. The wave motion further increases the load on the anode and the spacer frame to which the anode is attached, in addition to the water flow. The increased load may cause damage to the anode and / or the spacer frame, for example, it may bend or break the spacer frame. The design of the cathodic protection device according to the present invention reduces the gripping of foreign objects in the cathodic protection device, and therefore, the design of the cathodic protection device can be made more efficient, that is, it does not need to be more robust. For example, potentially, a lighter spacer tube can be used because of the lower cost compared to the prior art spacer frame. Therefore, the present invention also enables the efficient use of synthetic materials to form the spacer tube.

[0077] The cathodic protection device is configured to provide cathodic protection to a marine structure. The marine structure can be designed as a cylindrical foundation structure or a truss-shaped jacket for supporting a wind turbine. However, the structure may also be designed to support a platform for housing electrical equipment, or may be designed as a platform for an oil or gas production facility or an oil or gas exploration facility. It is further proposed that the marine structure may be a land structure or a floating structure such as a floating wind turbine support structure.

[0078] The present invention provides an offshore structure such as a transition piece for supporting a wind turbine, and an offshore structure provided with one or more cathodic protection devices according to the present invention.

[0079] In a further embodiment, the offshore structure is a cylindrical offshore structure such as a transition piece for supporting a wind turbine.

[0080] In still a further embodiment, one or more cathodic protection devices are attached to a mounting portion provided on the offshore structure such that the spacer tube axis and the anode axis extend at an angle with respect to the horizontal in a direction at an angle with respect to the outer surface of the offshore structure, so that the object that catches on the spacer tube slides along the spacer tube and the anode and slides off the cathodic protection device by the cathodic protection device pointing downward. Therefore, the object caught on the spacer tube slides downward along the spacer tube and the anode so as to come off the cathodic protection device.

[0081] The present invention provides an impressed current cathodic protection system comprising a cathodic protection device according to the present invention. The present invention further provides a transition piece provided with a cathodic protection device according to the present invention, and preferably, one or more spacer tubes of the cathodic protection device are at an angle in the range of 1 to 8 degrees with respect to a plane perpendicular to the longitudinal axis of the transition piece.

[0082] The present invention is a cathodic protection device for use in an impressed current cathodic protection system (ICCP system) for providing cathodic protection to an offshore structure such as a wind turbine foundation pile, - a spacer tube extending along the spacer tube axis between a foot end and a head end and having a continuous cross-section with the spacer tube axis at the center of the cross-section when viewed in the direction from the foot end to the head end, - A flange having a mounting surface for mounting a cathodic protection device on the mounting surface of a dedicated mounting portion of an offshore structure, preferably a mounting surface of the flange extending at a small angle with respect to the spacer tube axis, i.e., in the range of 1 to 8 degrees, and the flange being connected to the spacer tube at the foot end of the spacer tube, - A tubular anode having a central tubular anode axis and mounted across the spacer tube at the head end of the spacer tube, wherein the outer surface of the anode is recessed with respect to the outer surface of the spacer tube, and the anode axis is aligned with the spacer tube axis, such that a flexible object can slide along the spacer tube from the foot end to the head end without being caught after a protrusion extending from the spacer tube or the anode, and can slide from the spacer tube to the anode, across the anode, and away from the anode, and the cross section of the anode is positioned within the outer periphery of the spacer tube at the head end of the spacer tube, - An anode housing, - A base at the foot end of the housing, and an upper part at the head end, and - One or more guide rails, An anode housing comprising, Comprising, The anode housing is mounted to the spacer tube at the head end of the spacer tube by the base, and one or more guide rails extend parallel to the anode axis between the base and the upper part of the housing along the anode, the anode surface is recessed with respect to the outer periphery of the spacer tube at the head end of the spacer tube, each of the guide rails has a guide surface facing outward that is flush with the base of the housing and flush with the outer periphery of the spacer tube at the head end of the spacer tube, and the outer surface of the housing, i.e., the outer surface of the base of the housing, the guide rails, and the upper part form a continuation of the outer surface of the spacer tube, and further provides a cathodic protection device.

[0083] The present invention relates to a cylindrical offshore structure such as a transition part for supporting a wind turbine or a foundation pile, wherein the offshore structure is provided with one or more cathodic protection devices, and the cathodic protection devices are - A spacer tube that extends along a spacer tube axis between a foot end and a head end and has a continuous cross-section with the spacer tube axis at the center of the cross-section when viewed in the direction from the foot end to the head end. - A flange having a mounting surface for mounting a cathodic protection device on a mounting surface of a dedicated mounting portion of an offshore structure. Preferably, the mounting surface of the flange extends at a small angle with respect to the spacer tube axis of the spacer tube, that is, at an angle in the range of 1 to 8 degrees. The flange is connected to the spacer tube at the foot end of the spacer tube. - A tubular anode having a central tubular anode axis, the tubular anode being mounted on the spacer tube at the head end of the spacer tube, and the cross-section of the anode being positioned inside the outer periphery of the spacer tube at the head end of the spacer tube with the anode axis aligned with the spacer tube axis. - A plurality of guide rails extending parallel to the anode axis along the anode, one or more of the guide rails preferably extending parallel to the spacer tube axis. Each of the guide rails has an outward-facing guide surface that is flush with the outer periphery of the spacer tube at the head end of the spacer tube, such that a flexible object can slide along the spacer tube from the foot end to the head end, slide from the spacer tube to one or more of the guide rails, and then slide off the anode along the anode without getting caught after protruding from the spacer tube or the anode. Comprising One or more cathodic protection devices are provided on a mounting portion of an offshore structure in a state where the spacer tube axis and the anode axis extend at an angle with respect to the horizontal, such that the cathodic protection device pointing downward promotes the object to slide along the spacer tube and the anode and slide off the cathodic protection device. A cylindrical offshore structure is further provided, which is attached to the mounting surface of the cathodic protection device.

[0084] In the previous embodiment, the guide rail can be replaced with a net, the net extends parallel to the spacer tube axis, and each of the nets allows a flexible object to slide along the spacer tube from the foot end to the head end, from the spacer tube to the net, and then across the anode and away from the anode without getting caught after the protrusion extending from the spacer tube or the net. The net has a guiding surface facing outward that is flush with the outer circumference of the spacer tube at the head end of the spacer tube so that the flexible object can slide along the spacer tube, across the anode, and away from the anode without getting stuck.

[0085] The present invention further provides a cathodic protection device for use in an impressed current cathodic protection system for marine structures, the cathodic protection device comprising a synthetic spacer tube, a flange, and a tubular anode. In an embodiment of the cathodic protection device according to the present invention, the spacer tube has an outer surface without protrusions, and the tubular anode is mounted on the spacer tube near the head end of the spacer tube such that the anode surface is flush with the outer surface without protrusions of the spacer tube, or is recessed with respect to the outer surface without protrusions of the spacer tube, or alternatively, the tubular anode is provided in an anode housing mounted on the spacer tube, and the housing has an outer surface that is flush with the outer surface without protrusions of the spacer tube. In such an embodiment, the guiding surface facing outward of the guiding rail of the housing is part of the outer surface of the housing. Thus, the flexible object can slide along the spacer tube from the spacer tube to the anode or anode housing, across the anode or anode housing, and away from the anode or anode housing without being immobilized.

[0086] According to the present invention, the tubular anode is mounted on the spacer tube at the head end of the spacer tube with the anode axis of the tubular anode coinciding with the spacer tube axis of the spacer tube and with the anode radius or housing radius being at most 1.35 times the spacer tube radius. By setting up the anode as a continuation of the spacer tube in this way, the flexible object can slide along the spacer tube from the foot end to the head end, from the spacer tube to the anode or anode housing, across the anode or anode housing, and away from the anode or anode housing.

[0087] Accordingly, the present invention relates to a cathodic protection device for use in an impressed current cathodic protection system for marine structures. The device comprises a spacer tube, a flange, and a tubular anode. According to the present invention, the tubular anode axis coincides with the spacer tube axis of the spacer tube, and the anode radius is at most 1.35 times the spacer tube radius. When the tubular anode is provided in an anode housing attached to the spacer tube, the housing radius is at most 1.35 times the spacer tube radius. Accordingly, the cathodic protection device has a linear configuration to enable a flexible object to slide along the spacer tube from the spacer tube, onto and across the anode or anode housing, and off the anode or anode housing without getting stuck.

[0088] The present invention provides an impressed current cathodic protection system comprising one or more cathodic protection devices according to the present invention.

[0089] The present invention further provides a method for providing cathodic protection to a marine structure using a cathodic protection device according to the present invention. The method may include the step of attaching the cathodic protection device to the marine structure with the spacer tube axis at an angle relative to the horizontal.

[0090] The present invention is a method for manufacturing a cathodic protection device, comprising: - providing a spacer tube having an end wall at an upper end; - guiding one or more wires through the spacer tube and one or more openings in the end wall of the spacer tube; - attaching one or more anode elements in an anode housing; - attaching the anode housing to a head end such that a connector chamber is created at the upper end of the spacer tube; - connecting one or more wires to one or more anode elements; - For example, to seal the connection between the wire and the anode element, preferably to fix the anode housing to the spacer tube, a curable resin material is flowed into the space between the outer-facing spacer tube surface and the anode housing at the end of the spacer tube, and a step of filling the connector chamber with the curable resin material is performed. A method including the above is further provided.

[0091] The present invention further provides a cathode corrosion protection device provided by the above method, preferably a cathode corrosion protection device according to claim 1 having a connection chamber filled with a curable resin material by this method.

[0092] Advantageous embodiments of the cathode corrosion protection device according to the present invention and the method according to the present invention are disclosed in the dependent claims and this description, in which the present invention is further illustrated and explained based on some exemplary embodiments partially shown in schematic drawings. In the figures, corresponding components are provided with the same last two digits of the reference numerals from the perspective of the building and / or function.

Brief Description of the Drawings

[0093]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Best Mode for Carrying Out the Invention

[0094] Although mainly presented for illustrative purposes with reference to one or more of the figures, some of the technical features addressed below can be combined with any of the independent claims of this application either alone or in any other technically possible combination with one or more other technical features.

[0095] FIG. 1 shows a side view of a first cathodic protection device 1 for use in an impressed current cathodic protection system (ICCP system) for providing cathodic protection to an offshore structure such as a wind turbine foundation. FIG. 2 is a side view in cross-section of the cathodic protection device 1 of FIG. 1.

[0096] The cathodic protection device 1 includes a spacer tube 2, a flange 3, and a tubular anode 4. In both FIGS. 1 and 2, the intermediate region of the spacer tube is omitted.

[0097] The spacer tube 2 has an outward-facing spacer tube surface 26 that extends along a spacer tube axis 5 between a foot end 6 and a head end 7 of the spacer tube. The spacer tube 2 has a spacer tube radius 24 that extends between the spacer tube axis 5 and the spacer tube surface 26.

[0098] The flange 3 has a mounting surface 9 for mounting the cathodic protection device 1 to a mounting surface of a mounting portion of the offshore structure. The flange 3 is connected to the spacer tube 2 at the foot end 6 of the spacer tube 2.

[0099] The tubular anode 4 has an outward-facing anode surface 10 that extends along an anode axis 11 between a foot end 31 and a head end 32 of the tubular anode. The tubular anode 4 has an anode radius 34 that extends between the anode axis 11 and the anode surface 10.

[0100] According to the present invention, the tubular anode 4 is attached to the spacer tube 2 at the head end 7 of the spacer tube 2 in a state where the tubular anode axis 11 coincides with the spacer tube axis 5 of the spacer tube 2 and the anode radius is at most 1.35 times the spacer tube radius. By setting up the anode as a continuation of the spacer tube in this way, a flexible object can slide along the spacer tube from the foot end to the head end and can slide from the spacer tube, onto the anode, across the anode, and away from the anode.

[0101] In the embodiments shown in FIGS. 1 and 2, the tubular anode 4 is received in an anode housing 12. The anode housing 12 includes an anode cover 37 and includes a net 35 in the illustrated embodiment. The anode cover 37 has an outward-facing guide surface 36 that extends parallel to the anode surface 10 for guiding an object across the anode surface 10. The anode housing 12 has a housing radius 25 that extends between the anode axis 11 and the outward-facing guide surface 36 of the net 35. According to the present invention, the housing radius 25 is less than 1.35 times the spacer tube radius 24.

[0102] Furthermore, in the illustrated exemplary embodiment shown in FIGS. 1 and 2, the anode housing 12 further includes a base 19 at the foot end 20 of the housing 12 and an upper portion 21 at the head end 22 of the housing 12. The anode cover 37 extends between the base 19 and the upper portion 21, and the anode housing 12 is attached across the head end 7 of the spacer tube 2 by the base 19. The base 19 of the anode housing 12 and the upper portion 21 of the anode housing 12 each have an outward-facing surface, and those surfaces are flush with the guide surface 36 of the net 35.

[0103] In the illustrated exemplary embodiment, the base 19 of the housing is conical to facilitate the sliding of an object sliding along the spacer tube onto and across the tubular anode, providing an inclination between the spacer tube surface and the guide surface of the cover.

[0104] In the illustrated exemplary embodiment, the tubular anode 4 includes a first anode element 38 and a second anode element 39. FIG. 8 shows an exploded view of the anode housing 12. The anode housing 12 includes an upper part 40 that forms the upper part 21 of the housing, and a base part 41 that forms the base of the anode housing. The base part 41 and the upper part 40 are attached to the cylindrical housing body 42 of the anode housing. A cylindrical mesh 35 is to be mounted between the base part 41 and the upper part 40 of the anode housing 12.

[0105] In the illustrated exemplary embodiment, both the first anode element 38 and the second anode element 39 are semi-cylindrical. They each extend over an arc of 180 degrees. When the cathodic protection device 1 is attached to an offshore structure, the first anode element 38 is oriented downward, i.e., on the side of the cathodic protection device facing the seabed.

[0106] Thus, in the illustrated exemplary embodiment, the tubular anode 4 includes a plurality of anode elements. In a specific embodiment, the first anode element 38 and the second anode element 39 are each connected to a wire inside the anode housing. A connector 43 projects into a connector chamber 44 through an opening in the anode housing. In the connector chamber 44 shown in cross-section in FIG. 2, the connector is connected to a wire 45 coming from a spacer tube. The wire passes through the wall into the interior space of the spacer tube.

[0107] Thus, in the illustrated exemplary embodiment, the anode housing 12 is attached to the spacer tube 2 such that a connector chamber 44 is formed. The anode housing 12, more specifically the cylindrical housing body 42 of the anode housing 12, includes the head end 7 of the spacer tube 2 at the foot end 20 of the anode housing, and includes the connector chamber 44 at the head end 22 of the anode housing. During the manufacture of the cathodic protection device 1, after the anode housing 12 is attached to the spacer tube 2 and after the wire is connected to the connector 43, the connector chamber is filled with a curable resin material that seals the connector chamber and, by extension, the connection. For example, a thermosetting material can be used to fill the connector chamber.

[0108] In the illustrated embodiment, the connector elements 38, 39 are each connected to a dedicated wire. Thus, if the power supply of one anode element, or of one of the anode elements, fails, at least one other anode element is still supplied with power. Thus, the anode can still create a field even when a part of the anode is no longer operating.

[0109] The cathodic protection device 1 can be manufactured using the method according to the invention, the method comprising: - providing a spacer tube 2 having an end wall 46 at the head end 22; - guiding a wire 45 through the spacer tube 2 and an opening 47 in the end wall 46 of the spacer tube 2 and sealing the wire at the opening; - mounting a first anode element 38 and a second anode element 39 within the anode housing 12; - mounting the anode housing 12 to the head end 22 of the spacer tube 2 such that a connector chamber 44 is created at the head end 22 of the spacer tube 2; - connecting the wire 45 to the anode elements 38, 39; - flowing a curable resin material into the space between the outward-facing spacer tube surface 26 and the anode housing 12 at the head end 22 of the spacer tube 2 to fill the connector chamber 44 in order to seal the connection between the wire 45 and the anode elements 38, 39 and to fix the anode housing 12 to the spacer tube 2; and including.

[0110] FIG. 3 shows a perspective view of a second cathodic protection device 1 according to the invention for use in an impressed current cathodic protection system (ICCP system) for providing cathodic protection to an offshore structure such as a wind turbine foundation pile.

[0111] The cathodic protection device 1 comprises a synthetic spacer tube 2, a flange 3, and a tubular anode 4.

[0112] In the illustrated embodiment, the synthetic spacer tube 2 extends between the foot end 6 and the head end 7 along the spacer tube axis 5 depicted in the side view shown in FIG. 4. The spacer tube has an outer surface 8 without protrusions when viewed in the direction from the foot end 6 to the head end 7.

[0113] The flange 3 has a mounting surface 9 for mounting the cathodic protection device 1 to the mounting surface of the mounting part of the marine structure. The flange 3 is connected to the spacer tube 2 at the foot end 6 of the spacer tube 2.

[0114] The tubular anode 4 has an outward-facing anode surface 10 that is parallel to the central tubular anode axis 11 depicted in FIG. 4.

[0115] In the illustrated embodiment, the tubular anode 4 is provided in an anode housing 12 that is mounted to the spacer tube 2 at the head end 7 of the spacer tube 2. The housing 12 has an outer surface 13 that is flush with the outer surface 8 without protrusions of the spacer tube 2 such that a flexible object can slide along the spacer tube 2 from the foot end 6 to the head end 7 without being caught after protruding from the spacer tube 2, the anode housing 12, over the anode housing 12, and out of the anode housing 12.

[0116] In an alternative embodiment, it is proposed that the tubular anode be mounted across the spacer tube near the head end of the spacer tube such that the anode surface is flush with or recessed relative to the outer surface without protrusions of the spacer tube. Preferably, the anode surface is recessed relative to the outer surface without protrusions of the spacer tube, and a guide net or guide rail is provided to guide a sliding object across the outer surface of the anode.

[0117] FIG. 7 shows the cathodic protection device 1 according to the invention mounted to a transition piece 14. The transition piece 14 is mounted to a foundation pile 15 and supports an offshore wind turbine 16. It is proposed that the foundation pile and, by extension, the transition piece typically have a cylindrical configuration.

[0118] The flange 3 of the cathodic protection device 1 is connected to the spacer tube 2 at the foot end 6 of the spacer tube 2. Accordingly, the flange projects outwardly with respect to the spacer tube. In the illustrated embodiment, the flange is provided with a chamfered transition portion between the surface of the spacer tube without protrusion and the flange.

[0119] The transition part 14 is provided with a mounting part 17 having a flange with a mounting surface similar to the mounting surface of the flange 3 of the cathodic protection device 1. The cathodic protection device 1 is bolted to the flange of the mounting part in the transition part 14 with its flange 3.

[0120] When viewed in the direction facing the head 7 of the spacer tube 2 from the flange 3, the cathodic protection device 1 has an outer surface 8 without protrusion of the spacer tube 2 and the anode 4, and thus is configured to provide a minimal grip on the object and, by extension, to prevent the object from becoming immobile after the cathodic protection device.

[0121] The spacer tube 2 sets the tubular anode 4 at a distance from the object to be protected. The spacer tube 2 has an outer surface 8 without protrusion and has a continuous cross-section along the longitudinal axis of the spacer tube 2. The continuous outer surface, that is, without protrusion, in combination with the tubular anode, a tubular housing having an outer surface that is set up coaxially with the spacer tube and flush with the outer surface of the spacer tube prevents the object from becoming immobile in the cathodic protection device.

[0122] In the illustrated preferred embodiment, the spacer tube has a circular cross-section and, when mounted on the building to be protected, has an upward-facing surface that slopes laterally and downwardly, that is, an upward-facing surface when viewed in a plane perpendicular to the longitudinal axis of the spacer tube. Accordingly, gravity can cause an object that has fallen on the upper surface to slide off the spacer tube. Furthermore, the circular cross-section also allows an object that is horizontally pushed against the side surface of the spacer tube by a sea current to easily slide off the spacer tube.

[0123] The cathode corrosion protection device 1 includes a tubular anode 4 having a continuous or semi - continuous anode surface 10 that extends 360 degrees around the anode axis parallel to the anode axis 11, that is, an anode is provided. In the illustrated embodiment, both the spacer tube and the anode have a circular cross - section.

[0124] The anode surface 10 is cylindrically arranged around the anode axis so as to be parallel to the central anode axis 11 and to face away from the central anode axis 11. The tubular anode is attached to the spacer tube at the head end of the tubular anode in a state where the central tubular anode axis 11 is parallel to the spacer tube axis of the spacer tube and is aligned with the spacer tube axis.

[0125] In an embodiment, the cross - section of the anode is the same as the cross - section of the spacer tube at the head end of the spacer tube or is positioned within the cross - section of the spacer tube and has an anode axis aligned with the spacer tube axis. Thus, a flexible object can slide along the spacer tube from the foot end to the head end without being caught after a protrusion extending from the spacer tube or the anode, and can slide from the spacer tube, onto the anode, across the anode, and away from the anode.

[0126] In the illustrated embodiment, the cross - section of the anode is positioned within the cross - section of the spacer tube at the head end of the spacer tube. Thus, the anode surface is recessed with respect to the outer surface of the spacer tube.

[0127] Furthermore, in the illustrated embodiment, a guide rail 17 extending parallel to the anode axis 11 along the anode surface 10 is provided. The guide rail 17 is part of the anode housing 12. The anode housing further includes a base 19 at the foot end 20 and an upper part 21 at the head end 22 of the housing.

[0128] The guide rail 17 extends between a base portion 19 and an upper portion 21. The anode housing 12 is mounted on the spacer tube 2 at the head end 7 of the spacer tube 2 by the base portion 19, and the base of the anode housing has a cross-section similar to that of the spacer tube at the head end of the spacer tube such that the outer surface of the housing forms a continuation of the outer surface of the spacer tube.

[0129] Accordingly, the anode housing protects the anode surface, and a flexible object can slide along the spacer tube from the foot end to the head end without being caught after a protrusion extending from the spacer tube or the anode housing, and can slide from the spacer tube to the anode housing, across the anode housing, and away from the anode housing.

[0130] Each of the guide rails 17 has a guide surface 18 facing outward and flush with the surface 8 of the spacer tube 2 such that the guide surfaces of the spacer tube and the guide rail form a continuous guide surface that enables a flexible object to slide from the foot end 6 to the head end 7, and from the spacer tube 2 to the guide rail 17 along the spacer tube without being caught after a protrusion extending from the spacer tube or the guide rail, and thus to slide across the anode 4 and away from the anode 4. Accordingly, in such an embodiment, one or more guide rails have an outer circumference similar to that of the outer circumference of the spacer tube at the head end of the spacer tube, and the guide surfaces of the one or more rails form a continuation of the outer surface of the spacer tube.

[0131] Furthermore, the spacer tube, the guide rail, and the anode preferably extend along a single axis. Accordingly, in such an embodiment, the guide surfaces of the one or more guide rails are aligned with the outer circumference, i.e., the outer surface, of the spacer tube at the head end of the spacer tube, and the guide surfaces of the one or more guide rails form a continuation of the outer surface of the spacer tube.

[0132] In an alternative embodiment, the anode extends between the foot end and the head end, and the cross-section of the anode at the foot end is the same as the cross-section of the spacer tube at the head end of the spacer tube. In such an embodiment, the tubular anode forms a continuation of the spacer tube, and more specifically, the outer surface of the tubular anode forms a continuation of the outer surface of the spacer tube, i.e., there is no significant depression, recession, or protrusion at the transition from the outer surface of the spacer tube to the outer surface of the tubular anode.

[0133] In another alternative embodiment, the anode surface is recessed with respect to the outer surface of the spacer tube, and a mesh extending parallel to the anode axis along the anode surface is provided. The mesh allows a flexible object to slide along the spacer tube from the foot end to the head end, and from the spacer tube to the mesh and then off the anode without getting caught on a protrusion extending from the spacer tube or the mesh. To this end, the spacer tube and the mesh form a guiding surface without continuous protrusions, and have an outward-facing guiding surface flush with the surface of the spacer tube.

[0134] Thus, in such an embodiment, the guiding mesh has an outer perimeter similar to the outer perimeter of the spacer tube at the head end of the spacer tube, and the outer surface of the mesh forms a continuation of the outer surface of the spacer tube. Further, the spacer tube, the guiding mesh, and the anode extend along a single straight axis.

[0135] In the illustrated embodiment, the guiding rail 17 extends parallel to the spacer tube axis 5 in such an embodiment, and the edges of the guiding rail extend parallel to the longitudinal axis of the spacer tube and the anode axis, thus further reducing the possibility that an object sliding in the longitudinal direction of the cathodic protection device will become immobile.

[0136] Figure 7 is a schematic side view of an offshore structure 23 provided with a cathodic protection device 1. The offshore structure 23 includes a foundation pile 15, a transition component 14 attached to the foundation pile 15, and a wind turbine 16 having a mast 27 attached to the transition component 14.

[0137] In the illustrated embodiment, the cathodic protection device 1 is attached to the transition component 14.

[0138] At the head end of the spacer tube 2, the uppermost point 28 of the cross-section of the spacer tube 2 is at the 12 o'clock position, that is, facing upward. The lowermost point 18 of the cross-section is at the 6 o'clock position. In the illustrated embodiment, the guide rail 17a is arranged at the 12 o'clock position.

[0139] The surface of the guide rail 17a forms an extension of the surface of the spacer tube 2. Thus, the surface of the guide rail and the surface of the spacer tube form a non-protruding surface such that an object sliding along the cathodic protection device 1 can slide from the surface of the spacer tube to the guide surface of the guide rail and then slide off the guide rail so as to come off the cathodic protection device.

[0140] In a further embodiment, as an alternative or addition to the guide rail at the 12 o'clock position, a guide rail is provided at the 10 o'clock position and a guide rail is provided at the 2 o'clock position.

[0141] Preferably, the rail at the 12 o'clock position has a width such that the guide surface of the guide rail extends along at least 10% of the circumference, that is, a width extending over an angle of at least 36 degrees. By providing a wide guide surface on the guide rail, the protection of the anode surface is enhanced. When a plurality of guide rails are provided, the guide rails can have relatively narrow guide surfaces and still prevent an object from damaging the anode surface.

[0142] In the illustrated embodiment, the anode housing 12 and the spacer tube 2 are modular components that are combined to form a cathodic protection device. Such embodiments can provide spacer tubes of different lengths, such as an anode housing with one tubular anode and an anode housing with two or more tubular anodes, and these can be combined into a cathodic protection device configured for a specific object to be protected. For example, FIG. 6 shows a spacer tube 2 similar to one of the cathodic protection devices shown in FIGS. 3-5, and this spacer tube 2 is combined with an anode housing 12' having two tubular anodes 4a, 4b.

[0143] FIG. 7 shows a cylindrical marine structure 23, and in the specific embodiment shown, the transition component 14 supports the wind turbine 16. Two cathodic protection devices 1 are provided on the transition component. Each cathodic protection device 1 includes a spacer tube 2, a flange 3, and a tubular anode 4.

[0144] The spacer tube 2 extends along the spacer tube axis 5 between the foot end 6 and the head end 7. The spacer tube 2 has a continuous cross-section with the spacer tube axis 5 at the center of the cross-section when viewed in the direction from the foot end to the head end.

[0145] The flange 3 has a mounting surface for mounting the cathodic protection device 1 on the mounting surface of a dedicated mounting portion 30 of the transition component 14. The flange 3 is connected to the spacer tube 2 at the foot end 6 of the spacer tube with a mounting surface of the flange that extends at a small angle with respect to the spacer tube axis 5 of the spacer tube 2, that is, at an angle in the range of 1 to 8 degrees.

[0146] The tubular anode 4 has a central tubular anode axis 11. The tubular anode 4 is mounted on the spacer tube 2 at the head end 7 of the spacer tube 2 in a state where the cross-section of the anode 4 is positioned inside the outer periphery of the spacer tube 2 at the head end of the spacer tube 2 and the anode axis 11 is aligned with the spacer tube axis 5.

[0147] In the illustrated embodiment, the cathode corrosion protection device 1 is provided with a plurality of guide rails, and these guide rails extend parallel to the anode axis along the anode, similar to the guide rails of the embodiment shown in FIGS. 3 to 6. The guide rails extend parallel to the spacer tube axis, and each of the guide rails allows a flexible object to slide along the spacer tube from the foot end to the head end without getting caught after a protrusion extending from the spacer tube or the anode, slide from the spacer tube to one or more guide rails, and thus, across the anode, be able to slide so as to come off the anode. At the head end of the spacer tube, it has a guiding surface facing outward that is flush with the outer periphery of the spacer tube.

[0148] Furthermore, the cathode corrosion protection device 1 is attached to the mounting portion 30 provided on the transition part 14 in a state where the spacer tube axis 5 and the anode axis 11 extend in a direction at an angle with respect to the horizontal, by the mounting surface 9 of the cathode corrosion protection device 1. Therefore, each of the cathode corrosion protection devices points downward, facilitating the object to slide along the spacer tube and the anode and slide so as to come off the cathode corrosion protection device.

[0149] Therefore, in the embodiment shown in FIG. 6, the tubular anode 4 is the first tubular anode 4a, and the cathode corrosion protection device is provided with a second tubular anode 4b. In the illustrated embodiment, the first tubular anode 4a and the second tubular anode 4b are the same as the first tubular anode 4. The second tubular anode 4b is coaxially mounted with the first anode 4a in a single anode housing 12 such that the central anode axis 11 of the second anode 4b coincides with the central anode axis 11 of the first anode 4a.

[0150] In the embodiment, the second tubular anode is redundant and is only used when the first tubular anode is broken. Additionally, or alternatively, the second tubular anode is used when the first tubular anode does not provide a sufficiently strong field. In an alternative embodiment, both anode elements are operating during the use of the cathode corrosion protection device.

[0151] In the embodiments shown in FIGS. 3 to 6, the spacer tube and the anode housing are separate components that are combined during the assembly of the cathode corrosion protection device. In an alternative embodiment, at least a part of the spacer tube and the anode housing is a single part, and the anode is attached to a part of the anode housing that is an integral component with the spacer tube.

[0152] In the illustrated embodiment, the spacer tube is hollow, and one or more cables for connecting the anode to a power source and / or a control unit are guided from the housing to the flange through the hollow spacer tube.

[0153] Furthermore, in the illustrated embodiment, the spacer tube and the anode housing are made of a composite material, preferably a fiber-reinforced composite material. Therefore, the spacer tube is not conductive. Furthermore, for this reason, the spacer tube can be made of a relatively lightweight material, and the cathode corrosion protection device can be kept lightweight.

[0154] Furthermore, in the illustrated embodiment, the flange of the cathode corrosion protection device is a separate component that is attached to the spacer tube during the manufacturing process. In the illustrated embodiment, the flange is made of steel, and the spacer tube is made of a composite material.

[0155] For each of the embodiments shown in FIGS. 3 to 6, the flange is connected to the spacer tube in a state where the mounting surface of the flange extends perpendicular to the longitudinal spacer tube axis of the spacer tube.

[0156] In an alternative embodiment of the cathodic protection device 1 according to the invention, schematically shown in FIG. 7, the flange 3 extends at an angle with respect to the spacer tube axis 5 of the spacer tube 2 so that the cathodic protection device 1 can be mounted on the marine structure 23 at an angle with respect to the horizontal, i.e., at an angle in the range of 1 to 8 degrees. That is, it is connected to the spacer tube 2 at the mounting surface 9 of the flange 3 that extends at an angle. This configuration allows the cathodic protection device to be mounted on the marine structure, in this specific case on the transition part, with the spacer tube axis of the spacer tube pointing downwards, which facilitates the object to slide away from the flange and disengage from the cathodic protection device.

[0157] In an embodiment, the cathodic protection device further comprises a reference cell and a reference cell support bracket. The reference support bracket is configured to be mounted on the flange, and preferably, is configured to be mounted between the flange and a dedicated mounting part of the marine structure. By providing the reference cell on the bracket mounted on the mounting surface, instead of the spacer tube, the reference cell can be mounted near the anode while the spacer tube can remain non-protruding.

[0158] In an embodiment, the reference cell is provided on the bottom side of the cathodic protection device, i.e., on the side facing towards the seabed during use, so that an object cannot easily get caught on it afterwards. Further, in this position, the reference cell or its support bracket can prevent the object from sliding along the spacer tube towards the housing of the cathodic protection device.

Explanation of Reference Signs

[0159] 1 Cathodic protection device 2 Spacer tube 3 Flange 4 Tubular anode 5 Spacer tube axis 6 Spacer tube foot end 7 Spacer tube head end 8 Non-protruding spacer tube surface 9 Flange mounting surface 10 Outward-facing anode surface 11 Anode axis 12 Anode housing 13 Outer surface of the housing 14 Transition part 15 Foundation pile 16 Offshore wind turbine 17 Guide rail 18 Guide surface facing outward of the guide rail 19 Anode housing base 20 Foot end of the housing 21 Upper part of the anode housing 22 Head end of the housing 23 Offshore structure 24 Spacer tube radius 25 Housing radius 26 Outer-facing spacer tube surface 27 Wind turbine mast 28 Highest point of the cross-section of the spacer tube 29 Lowest point of the cross-section of the spacer tube 30 Mounting part on the offshore structure 31 Anode foot end 32 Anode head end 34 Anode radius 35 Mesh 36 Guide surface facing outward of the mesh 37 Anode cover 38 First anode element 39 Second anode element 40 Upper part of the anode housing 41 Base part of the anode housing 42 Cylindrical housing body of the anode housing 43 Connector 44 Connector chamber 45 Wire 46 End wall 47 Opening in the end wall

Claims

1. A cathodic protection device for use in an applied current cathodic protection system (ICCP system) to provide cathodic protection for offshore structures such as wind turbine foundations, A spacer tube having an outward-facing spacer tube surface extending along the spacer tube axis between the foot end and the head end of the spacer tube, and having a spacer tube radius extending between the spacer tube axis and the spacer tube surface, A flange having a mounting surface for attaching the cathode corrosion protection device to the mounting surface of the mounting portion of the marine structure, and a flange connected to the spacer pipe at the foot end of the spacer pipe, A tubular anode having an outward-facing anode surface extending along the anode axis between the foot end and the head end of the tubular anode, and having an anode radius extending between the anode axis and the anode surface, Equipped with, The tubular anode is mounted on the spacer tube at the head end of the spacer tube, with the tubular anode axis coinciding with the spacer tube axis of the spacer tube, and the anode radius is 1.35 times the spacer tube radius to the extent that the flexible object can slide along the spacer tube from the foot end to the head end, and can slide from the spacer tube to the anode, across the anode, and away from the anode. A cathode corrosion protection device comprising an anode housing, wherein the tubular anode is received in an anode housing, the anode housing being an anode cover such as a mesh or one or more guide rails, the anode cover having outward-facing guide surfaces extending parallel to the anode surface for guiding an object across the anode surface, the anode housing having a housing radius extending between the anode axis and the guide surfaces, the housing radius being up to 1.35 times the spacer tube radius.

2. The cathode corrosion protection device according to claim 1, wherein the anode housing further comprises a base at the foot end of the housing and an upper part at the head end of the housing, the cover extends between the base and the upper part, the anode housing is preferably mounted by the base across the head end of the spacer tube, the base and the upper part of the anode housing each have outward-facing surfaces, and the outward-facing surfaces of the base and the upper part are flush with the guide surface of the cover.

3. The cathodic protection device according to claim 1, wherein the tubular anode comprises a first anode element, the first anode element being semi-cylindrical and extending, for example, over an arc of at least 90 degrees, preferably over an arc of about 180 degrees, and preferably, when the cathodic protection device is mounted on the offshore structure, the first anode element is positioned downward, i.e., on the side of the cathodic protection device facing the seabed.

4. The cathodic protection device according to claim 3, wherein the tubular anode comprises a second anode element, the second anode element being semi-cylindrical, the first anode element and the second anode element each extending over an arc of about 180 degrees, and when the cathodic protection device is mounted on the offshore structure, the second anode element is positioned on the side of the cathodic protection device facing upward, that is, away from the seabed.

5. The cathode corrosion protection device according to claim 1 or 2, wherein the tubular anode is a first tubular anode, the cathode corrosion protection device is provided with a second tubular anode similar to the first tubular anode, and the first and second anodes are coaxially mounted in the anode housing according to claim 1.

6. The cathode corrosion protection device according to claim 1 or 2, wherein the spacer tube is made from a synthetic material, preferably from a fiber-reinforced synthetic material.

7. The cathode corrosion protection device according to claim 1 or 2, wherein the flange extends at an angle with respect to the axis of the spacer tube of the spacer tube, preferably at an angle in the range of 1 to 8 degrees, such as 5 degrees, so that the cathode corrosion protection device can be mounted on the offshore structure at an angle with respect to the horizontal, and is connected to the spacer tube at the mounting surface of the flange.

8. The cathodic protection device according to claim 1 or 2, further comprising a reference cell and a reference cell support bracket, wherein the reference support bracket is configured to be mounted on the flange, preferably mounted between the flange and the mounting portion of the offshore structure.

9. An offshore structure such as a transition component for supporting a wind turbine, wherein one or more of the cathodic corrosion protection devices described in claim 1 are provided.

10. The marine structure according to claim 9, which is a cylindrical marine structure such as a transition component for supporting a wind turbine.

11. The offshore structure according to claim 9 or 10, wherein the one or more cathode protection devices are attached to a mounting portion provided on the offshore structure, with the mounting surface of the cathode protection device such that the cathode protection device points downward, thereby facilitating the object to slide along the spacer tube and the tubular anode and slide away from the cathode protection device, with the spacer tube axis and the anode axis extending at a certain angle with respect to the horizontal.

12. An applied current cathode corrosion protection system comprising one or more cathode corrosion protection devices according to claim 1 or 2.

13. A method for providing cathodic protection to an offshore structure using the cathodic protection device described in claim 1 or 2.

14. A method for manufacturing a cathode corrosion protection device, preferably the method described in claim 1 or 2, The steps include providing a spacer pipe having an end wall at its head end, The steps include guiding one or more wires through the spacer tube and one or more openings in the end wall of the spacer tube, and sealing the wires in the one or more openings, A step of mounting one or more anode elements in the anode housing, The steps include: attaching the anode housing to the head end of the spacer tube such that a connector chamber is created at the head end of the spacer tube; The steps of connecting one or more wires to one or more anode elements, For example, the step of filling the connector chamber with the curable resin material to seal the connection between the wire and the anode element, preferably to fix the anode housing to the spacer tube, by flowing the curable resin material into the space between the outward-facing surface of the spacer tube and the anode housing at the head end of the spacer tube, A method that includes this.

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