Method for corrosion protection of wind turbine blades

Abstract

The present disclosure relates to the field of wind power generation technology, and provides a corrosion prevention method for a blade of a wind turbine generator. The method comprises the following steps: applying a thread locking agent to a first threaded end of a blade root bolt of the wind turbine generator, and sleeving a round sealing ring at a first preset position of a non-threaded portion of the blade root bolt; screwing the first threaded end into a mounting hole on a blade root flange end face, and ensuring that the round sealing ring is not exposed outside the mounting hole; sealing a gap between the blade root bolt and the mounting hole using a sealant; and performing segmented treatment on a second threaded end of the blade root bolt, the segmented treatment comprising corrosion prevention treatment and lubrication treatment. The present scheme can improve the reliability of the connection of the blade root bolt and improve the operation safety of the wind turbine generator.

Description

Technical Field

[0001] This disclosure relates to the field of wind power generation technology, and more specifically, to a method for corrosion prevention of wind turbine blades. Background Technology

[0002] During wind turbine operation, the blades bear complex alternating loads. The root bolts (i.e., blade root bolts) are the core fasteners connecting the blades and the hub, and their connection reliability directly affects the safe operation of the wind turbine. Blade root bolts are usually made of high-strength bolts and are exposed to harsh environments such as high salt spray, large temperature differences, and strong winds and sandstorms for a long time. They must withstand huge alternating tensile stresses and face serious corrosion risks.

[0003] The lack of corrosion protection methods for wind turbine blade root bolts in related technologies leads to insufficient operational safety of wind turbines.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this disclosure is to provide a method for preventing corrosion of wind turbine blades, thereby improving the operational safety of wind turbines to at least some extent.

[0006] Other features and advantages of this disclosure will become apparent from the following detailed description, or may be learned in part by practice of this disclosure.

[0007] According to one aspect of this disclosure, a method for preventing corrosion of wind turbine blades is provided, comprising: applying a thread-locking agent to a first threaded end of a blade root bolt of the wind turbine, and fitting a circular sealing ring at a first predetermined position on the unthreaded portion of the blade root bolt; screwing the first threaded end into a mounting hole on the end face of the blade root flange, ensuring that the circular sealing ring is not exposed outside the mounting hole; sealing the gap between the blade root bolt and the mounting hole using sealant; and performing segmentation treatment on the second threaded end of the blade root bolt, the segmentation treatment including corrosion prevention treatment and lubrication treatment.

[0008] Optionally, applying thread-locking agent to the first threaded end of the blade root bolt of the wind turbine unit includes applying thread-locking agent to the area encompassed by the first threaded end face to the halfway point of the first threaded end.

[0009] Optionally, the sealant is applied to the gap between the blade root bolt and the mounting hole, without extending beyond the blade root flange end face.

[0010] Optionally, screwing the first threaded end into the mounting hole on the blade root flange end face includes: screwing the first threaded end into the mounting hole on the blade root flange end face, and making the blade root bolt extend out of the blade root flange end face by a first preset length.

[0011] Optionally, the first preset length is determined based on the total thickness of the hub-side components to be connected by the leaf root bolt and the safety clearance required for installation.

[0012] Optionally, segmenting the second threaded end of the blade root bolt includes: determining the non-engaging section of the second threaded end of the blade root bolt that does not engage with the nut according to the installation design parameters of the blade root bolt, and applying cold galvanizing to the non-engaging section for corrosion protection; and applying grease to the engaging section of the second threaded end of the blade root bolt that contacts the nut for lubrication.

[0013] Optionally, the grease is applied after the cold galvanizing has dried.

[0014] Optionally, the method further includes: determining in advance the exposed section of the unthreaded portion of the blade root bolt after installation based on the installation design parameters of the blade root bolt, and applying cold galvanizing to the target exposed section near the second threaded end of the exposed section for corrosion protection.

[0015] Optionally, the method further includes applying cold galvanizing to the damaged portion of the unthreaded part of the blade root bolt for corrosion protection.

[0016] Optionally, the method further includes: applying sealant to the blade root flange for corrosion protection; wherein, the method of applying sealant to the blade root flange includes at least one of the following: applying sealant to the blade root flange before the blade is removed from the tooling, or applying sealant to the blade root flange after the blade is lifted off the blade lifting vehicle.

[0017] As can be seen from the above technical solution, the corrosion prevention method for wind turbine blades in the exemplary embodiment of this disclosure has at least the following advantages and positive effects: In some embodiments of this disclosure, the technical solutions provided include, on the one hand, applying thread-locking agent to the first threaded end of the blade root bolt to achieve thread loosening prevention and initial sealing; placing a circular sealing ring on the unthreaded portion of the bolt, ensuring it does not protrude from the mounting hole, thus achieving radial sealing between the bolt shank and the inner wall of the mounting hole; and then using sealant to seal the gap between the bolt and the mounting hole, forming a multi-level physical sealing barrier where the circular sealing ring and sealant cooperate. This multi-level sealing structure effectively prevents seawater, rainwater, and humid air from seeping into the blade root through the gap between the bolt shank and the inner wall of the mounting hole, fundamentally solving the problems of thread corrosion and reduced connection strength caused by poor sealing, and significantly improving the long-term corrosion resistance and connection reliability of the blade root bolt. On the other hand, based on physical sealing corrosion protection, this disclosure segments the blade root bolt, achieving complete isolation between the corrosion-resistant section and the lubrication section. This solves the problem of easy corrosion of exposed parts and avoids the influence of the anti-corrosion coating on the friction coefficient of the thread meshing area, effectively coordinating the contradiction between corrosion protection and lubrication, and ensuring the installation quality and long-term safe operation of the bolted connection.

[0018] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0020] Figure 1 A schematic diagram is shown of a method for corrosion protection of wind turbine blades that can be applied to embodiments of the present disclosure; Figure 2 A schematic diagram of a blade root bolt according to an exemplary embodiment of the present disclosure is shown; Figure 3 A flowchart illustrating a segmented processing method according to an exemplary embodiment of the present disclosure is shown. Figure 4 This diagram illustrates a segmentation process for the leaf root bolt in an exemplary embodiment of the present disclosure. Detailed Implementation

[0021] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this disclosure more comprehensive and complete, and to fully convey the concept of the example embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced with one or more of the specific details omitted, or other methods, components, apparatus, steps, etc., can be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0022] The terms “a,” “an,” “the,” and “the” are used in this specification to indicate the presence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first” and “second” are used only as markings and are not a limitation on the number of objects.

[0023] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0024] Water can easily seep into the blade root bolt connections of wind turbines, leading to internal corrosion of the blade roots. Unclear replacement procedures for tooling bolts may affect sealing performance. Furthermore, improper sequence of anti-corrosion and lubrication processes can result in lubrication failure or poor anti-corrosion effects.

[0025] To address the aforementioned problems, this disclosure provides a method for preventing corrosion of wind turbine blades.

[0026] Figure 1 This diagram illustrates a process flow illustration of a method for corrosion protection of wind turbine blades according to an exemplary embodiment of this disclosure. (Reference) Figure 1 The method includes: Step S110: Apply thread-locking agent to the first threaded end of the blade root bolt of the wind turbine, and place the circular sealing ring at the first preset position of the unthreaded part of the blade root bolt. Step S120: Screw the first threaded end into the mounting hole on the flange end face at the root of the blade, and ensure that the circular sealing ring is not exposed outside the mounting hole; Step S130: Seal the gap between the blade root bolt and the mounting hole using sealant; Step S140: The second threaded end of the blade root bolt is segmented, and the segmentation process includes anti-corrosion treatment and lubrication treatment.

[0027] exist Figure 1 In the technical solution provided by the illustrated embodiment, on the one hand, thread locking agent is applied to the first threaded end of the blade root bolt to achieve thread loosening prevention and initial sealing. A circular sealing ring is fitted onto the unthreaded part of the bolt and is not exposed outside the mounting hole to achieve radial sealing between the bolt shank and the inner wall of the mounting hole. Then, sealant is used to seal the gap between the bolt and the mounting hole, forming a multi-level physical sealing barrier with the circular sealing ring and sealant working together. This multi-level sealing structure can effectively prevent seawater, rainwater, and humid air from seeping into the blade root through the gap between the bolt shank and the inner wall of the mounting hole, fundamentally solving the problem of thread corrosion and reduced connection strength caused by poor sealing, and significantly improving the long-term corrosion resistance and connection reliability of the blade root bolt. On the other hand, based on physical sealing corrosion protection, this disclosure segments the blade root bolt to achieve complete isolation between the corrosion protection section and the lubrication section. This solves the problem of easy corrosion of the exposed part and avoids the influence of the anti-corrosion coating on the friction coefficient of the thread meshing area, effectively coordinating the contradiction between corrosion protection and lubrication, and ensuring the installation quality and long-term safe operation of the bolt connection.

[0028] Next, a detailed description will be given of the specific implementation method of "step S110, applying thread-locking agent to the first threaded end of the blade root bolt of the wind turbine and placing the circular sealing ring at the first preset position of the unthreaded part of the blade root bolt".

[0029] For example, a blade root bolt can be understood as a bolt at the root of a wind turbine blade used to connect the blade and the hub. A circular sealing ring can be understood as an O-ring.

[0030] A schematic diagram of the blade root bolt is shown below. Figure 2 As shown, the blade root bolt 200 is a double-ended stud structure, which includes a first threaded end 210, an unthreaded portion 220, and a second threaded end 230 connected sequentially along the axial direction. The first threaded end 210 is a short threaded end, used to be screwed into the mounting hole on the flange end face of the blade root; the unthreaded portion 220 is a smooth shank located in the middle section of the bolt; the second threaded end 230 is a long threaded end, used to connect with the pitch bearing and nut on the hub side after the blade is hoisted. The specific specifications of the bolt can be selected according to the wind turbine model and design load; this exemplary embodiment does not impose any special limitations on this.

[0031] For example, one embodiment of step S110 may include applying threadlocking agent to the area encompassed at the halfway point from the first thread end face to the first thread end.

[0032] For example, you can apply thread-locking agent to the short thread end of the bolt, starting from the bolt end face and applying it to half of the first thread end (i.e., the pre-embedded end). After application, allow it to dry.

[0033] Before applying the sealant, the first threaded end of the leaf root bolt should be cleaned. Specifically, use a cleaning cloth or industrial wiping paper soaked in industrial cleaning agent to wipe the threaded surface of the first threaded end to remove oil, dust, rust-preventive oil, or metal shavings, etc., to ensure that the thread-locking agent can fully penetrate and bond well with the threaded surface.

[0034] After cleaning and inspection, apply threadlocker to the threaded surface of the first threaded end. As mentioned earlier, the threadlocker is applied to the threaded area encompassed from the end face of the first threaded end (i.e., the frontmost face of the bolt) to halfway down the first threaded end. That is, apply the threadlocker to the first half of the thread closest to the end face of the first threaded end, and leave the second half (the half closest to the unthreaded portion) unapplied.

[0035] When the bolt is screwed into the mounting hole, only the first half of the thread engages with the pre-embedded threaded sleeve at the blade root, resulting in primary screwing and force contact. If the entire thread is coated with locking agent, excess adhesive will be squeezed out and may flow onto the unthreaded portion or outside the mounting hole, causing unnecessary contamination or cleaning difficulties. Controlling the application area to half the thread length from the end face ensures sufficient locking agent to fill the thread gap in the engaging section while preventing excessive adhesive overflow.

[0036] In one exemplary embodiment, the first preset position is at the 1 / 2 position of the unthreaded portion of the leaf root bolt.

[0037] For example, after the locking agent dries, the O-ring can be placed at the 1 / 2 position of the unthreaded part of the leaf root bolt. That is, the O-ring is located at the axial midpoint of the unthreaded part, which is approximately equal to the distance from the junction of the unthreaded part and the first threaded end and the distance from the junction of the unthreaded part and the second threaded end 130.

[0038] After the bolt is screwed into the mounting hole and adjusted to the predetermined extension length (e.g., 363±1mm), the unthreaded portion is positioned precisely near the opening of the mounting hole. Placing the O-ring over the center of the unthreaded portion ensures that it is pressed precisely inside the opening of the mounting hole after the bolt is in place, neither protruding beyond the hole nor extending excessively into it, thus achieving optimal sealing.

[0039] Next, a detailed description will be given of the specific implementation method of "step S120, screwing the first threaded end into the mounting hole on the end face of the blade root flange, and ensuring that the circular sealing ring is not exposed outside the mounting hole".

[0040] For example, screwing the first threaded end into the mounting hole on the blade root flange end face includes: screwing the first threaded end into the mounting hole on the blade root flange end face, and making the blade root bolt extend out of the blade root flange end face by a first preset length.

[0041] In one exemplary embodiment, the first preset length is determined based on the total thickness of the hub-side components to be connected to the blade root bolt and the safety clearance required for the installation operation.

[0042] For example, the first threaded end (short threaded end) of the blade root bolt can be screwed into the mounting hole on the flange end face of the blade root, ensuring that the O-ring pre-fitted on the unthreaded part is not exposed outside the mounting hole after the bolt is installed, thus laying the foundation for subsequent sealant sealing and secondary anti-corrosion treatment. This process can be carried out while the blade is on the transport vehicle and has not yet been unloaded.

[0043] Multiple mounting holes (the number depends on the blade model) are pre-drilled on the flange end face at the blade root, and these holes are evenly distributed circumferentially along the flange end face. A high-strength metal threaded sleeve (or pre-embedded threaded sleeve) is pre-embedded in each mounting hole. This threaded sleeve is integrally formed with the composite material at the blade root, and its internal thread matches the external thread of the first threaded end of the blade root bolt. The axis of the mounting hole is perpendicular to the flange end face, and its diameter is slightly larger than the outer diameter of the unthreaded portion of the blade root bolt to form an annular gap for compression sealing by the O-ring. After the bolt is screwed in, the end of the first threaded end should approach but not exceed the bottom of the mounting hole to ensure that the thread-locking agent can fully cure between the threads.

[0044] After aligning the first threaded end of the blade root bolt with the mounting hole, first rotate the bolt clockwise 2-3 turns by hand to confirm that the threads are properly engaged and there is no jamming. Then, use an Allen wrench to continue screwing it in until the end face of the first threaded end is completely inside the mounting hole. At this point, the O-ring begins to approach the opening of the mounting hole. During this continued screwing process, operate slowly and carefully observe the position of the O-ring. As the bolt goes deeper, the O-ring gradually enters the mounting hole and is pressed between the outer wall of the unthreaded portion of the bolt and the inner wall of the mounting hole. Continue screwing the bolt in until the O-ring is completely inside the mounting hole and no longer protrudes beyond 200mm from the flange end face. At this point, the O-ring is located inside the opening of the mounting hole, that is, below the flange end face (on the inside side of the blade root), and cannot be seen from the outside of the flange end face.

[0045] A specific method for determining whether an O-ring is exposed outside the mounting hole can include: during bolt screwing, when the O-ring reaches the opening of the mounting hole, the operator can visually observe the annular gap between the bolt and the hole at the flange end face. If the rubber material of the O-ring 300 is visible in this gap, it indicates that the O-ring has not fully entered the hole, and the bolt needs to be screwed in further; if only the unthreaded portion of the bolt and the metal surface between it and the inner wall of the mounting hole are visible at the flange end face, and the rubber material of the O-ring is not visible, it indicates that the O-ring has fully entered the mounting hole, meeting the requirement of "not exposed outside the mounting hole".

[0046] As an auxiliary means of judgment, a marking line can also be set on the unthreaded part of the bolt. Specifically, when installing the O-ring, a circular marking line is engraved on the unthreaded part, at a predetermined distance (this distance is calculated based on the depth of the mounting hole and the chamfer size of the orifice) on the side of the O-ring closest to the second thread. When this marking line just enters the orifice plane of the flange end face, it indicates that the O-ring has completely entered the mounting hole and is not exposed outside the hole.

[0047] In one exemplary embodiment, after the blade root bolt is screwed into the mounting hole, its second threaded end needs to protrude a predetermined length from the blade root flange end face, i.e., the first predetermined length. This first predetermined length is the basic length that allows the bolt to pass through the pitch bearing flange hole and be tightened with the nut during subsequent hub (pitch bearing) installation.

[0048] Taking a first preset length of 363±1mm as an example, that is, the distance between the outer surface of the flange end face at the blade root and the end face of the second threaded end of the blade root bolt should be controlled between 362mm and 364mm.

[0049] As mentioned above, the first preset length is determined based on the total thickness of the hub-side components to be connected by the leaf root bolt and the safety clearance required for installation. The first preset length can also be determined in conjunction with the deformation coordination allowance during operation.

[0050] For example, the components to be connected on the hub side include the thickness of the inner ring of the pitch bearing (typically 120mm–160mm), the thickness of the gasket (typically 8mm–12mm), and the thickness of the fastening nut (typically 40mm–60mm). The sum of these three constitutes the basic thickness through which the bolt needs to pass. Based on this, an operating safety clearance (typically 30mm–50mm, to provide operating space for fastening tools such as hydraulic tensioners) and a deformation coordination allowance (typically 20mm–40mm, to provide coordination space for the elastic deformation of the blade root area during wind turbine operation) are added, ultimately resulting in a first preset length of 363mm.

[0051] For example, during the bolt tightening process, the operator needs to continuously measure the length of the second threaded end extending beyond the flange face and adjust it by continuing to tighten or loosening the bolt appropriately. For instance, a steel ruler or depth caliper can be used, aligning the "0" mark of the ruler with the outer surface of the flange face at the blade root, and measuring along the bolt's axial direction to the end face of the second threaded end, reading the length. If the measured value is greater than 364mm (i.e., the bolt is too long), continue tightening the bolt clockwise, re-measuring after each 1 / 4 turn, until the length meets the requirement of 363±1mm. If the measured value is less than 362mm (i.e., the bolt is too short), use a wrench to loosen the bolt counterclockwise, re-measuring after each 1 / 4 turn, until the length meets the requirement of 363±1mm.

[0052] Because the threadlocker applied to the first thread end only cures in an oxygen-deficient environment, it remains liquid during bolt adjustment and does not affect the screwing in and unscrewing. After adjustment, the threadlocker gradually cures between the mating surfaces of the threaded pair, forming a strong locking layer.

[0053] By controlling the O-ring 300 to be positioned inside the mounting hole opening, a radial compression seal is formed between the outer wall of the bolt and the inner wall of the mounting hole. This effectively prevents moisture from seeping in through the opening without losing its sealing function due to excessive insertion. By controlling the length of the second threaded end extending beyond the flange end face within the range of 363±1mm, an accurate reference length is provided for subsequent hub installation and nut tightening, ensuring the smooth progress of subsequent installation procedures. After the bolt is screwed in, the thread-locking agent on the first threaded end gradually cures in the oxygen-deficient environment within the mounting hole, forming a strong locking layer between the threads, effectively preventing the bolt from loosening under long-term alternating loads. The O-ring not protruding outside the mounting hole creates an annular gap at the opening for sealant filling, providing favorable conditions for sealant application in subsequent step S130.

[0054] Next, a detailed description will be given of the specific implementation method of "step S130, sealing the gap between the leaf root bolt and the mounting hole with sealant".

[0055] For example, after the blade root bolt has been screwed into the mounting hole and adjusted to the predetermined extension length, sealant is used to seal the gap between the blade root bolt and the mounting hole, forming a multi-level physical sealing barrier together with the O-ring that is already located inside the mounting hole.

[0056] After steps S110 to S120, the first threaded end of the blade root bolt has been screwed into the mounting hole on the flange face at the blade root. The O-ring is completely inside the mounting hole and does not protrude outside the flange face. The second threaded end of the blade root bolt 100 extends 363±1mm beyond the flange face. At this point, a small annular gap is formed between the unthreaded portion of the blade root bolt and the inner wall of the mounting hole at the flange face. If this gap is not sealed, moisture and corrosive media may seep into the mounting hole along this gap, forming a leakage path that "bypasses" the O-ring. Therefore, sealant is needed to seal this annular gap, forming two lines of defense with the O-ring.

[0057] In one exemplary embodiment, sealant is applied to the gap between the blade root bolt and the mounting hole, without extending beyond the blade root flange end face.

[0058] For example, use sealant to seal the gap between the bolt and the mounting hole. The sealant should not extend beyond the flange face, and then clean up any excess sealant with a cloth. When applying sealant, be careful not to get it on the bolt threads. If sealant is accidentally applied to the threads, wipe it off immediately with a cloth, otherwise it will affect the installation of the blade nut.

[0059] In one exemplary embodiment, a suitable sealant can be selected based on the operating environment of the wind turbine and the inherent properties of the sealant. For example, wind turbines are typically installed in harsh environments such as coastal areas, deserts, and mountains, where the blade roots are exposed to complex environments such as strong ultraviolet radiation, high salt spray, large temperature differences, and strong winds and sandstorms for extended periods. The sealant should possess excellent resistance to ultraviolet radiation, salt spray corrosion, and alternating high and low temperatures, enabling it to maintain its sealing performance without degradation over long periods in these harsh environments.

[0060] For example, a glue-applying device (such as a glue-applying robot) can be controlled to seal the gap between the blade root bolt and the mounting hole according to pre-set instructions. The glue-applying robot may include a robotic arm, a glue gun mounted at the end of the robotic arm, and a controller. The controller has pre-stored glue-applying path parameters that match the diameter of the mounting hole, the outer diameter of the blade root bolt, and the size of the gap. During glue application, the robotic arm drives the glue gun to move at a uniform speed along the circumference of the gap, while the controller controls the glue gun to continuously extrude sealant at a preset flow rate and pressure, ensuring that the sealant continuously and evenly covers the entire circumference of the gap. After glue application, the glue-applying robot can also use a scraper or smoothing device at its end to level the applied sealant.

[0061] Of course, the application of adhesive can also be done manually, such as by an operator holding a glue gun and manually squeezing out sealant along the circumference of the gap. This exemplary embodiment does not impose any special limitations on this method.

[0062] Next, the specific implementation method of "step S140, segmenting the second threaded end of the leaf root bolt, the segmentation process including anti-corrosion treatment and lubrication treatment" will be described in detail.

[0063] For example, steps S110 to S130 above involve structural sealing. A physical sealing barrier is established for the blade root bolt holes using a bolt structure with O-rings and a sealant sealing process, which forms the basis for long-term corrosion protection. In step S140, a secondary corrosion protection treatment is performed, namely, differentiated surface treatment of the second threaded end of the blade root bolt. Specifically, corrosion protection and lubrication treatments are applied to different functional areas of the bolt to simultaneously meet the corrosion protection requirements of the exposed parts and the lubrication requirements of the threaded engagement parts.

[0064] For example, Figure 3 A flowchart illustrating a segmented processing method according to an exemplary embodiment of this disclosure is shown. (See reference...) Figure 3 The method may include steps S310 to S320, wherein: In step S310, based on the installation design parameters of the blade root bolt, the non-engaging section of the second threaded end of the blade root bolt that does not engage with the nut is determined, and the non-engaging section is coated with cold galvanizing for corrosion protection.

[0065] In one exemplary embodiment, the installation design parameters refer to a series of geometric dimensions and engineering data that are predetermined by the wind turbine manufacturer during the design phase and clearly marked in the installation drawings and technical documents during the installation process of the blade root bolts. These may include the length of the second threaded end, the thickness of the fastening nut, the thickness of the washer, the design requirements for the thread engagement length, and the allowance of the exposed thread at the end, etc.

[0066] For example, the sum of the thickness of the fastening nut, the thickness of the washer, the thread engagement length, and the exposed thread allowance at the end can be calculated, and then the non-engaging section in the second thread end can be determined based on the difference between the thread segment length of the second thread end and this sum.

[0067] Similarly, cold galvanizing can be applied to the non-engaging section of the second thread end by a cold galvanizing coating equipment (such as a cold galvanizing coating robot) according to a preset instruction, or it can be applied manually. This exemplary embodiment does not impose any special limitations on this.

[0068] In step S320, grease is applied to the meshing section of the second threaded end of the leaf root bolt that contacts the nut for lubrication.

[0069] For example, the engagement section in the second thread end of the leaf root bolt that contacts the nut can be determined according to the thread engagement length design requirements in the installation design parameters. Then, the grease can be applied by controlling the grease application robot or manually.

[0070] In one exemplary embodiment, the grease is applied after the cold galvanizing process has dried.

[0071] For example, after the cold galvanizing coating and drying are completed in step S310, grease is applied to the meshing section of the second threaded end of the leaf root bolt that contacts the nut for lubrication, ensuring precise control of the friction coefficient during subsequent nut installation. Applying the cold galvanizing coating first and allowing it to dry before applying the grease prevents the wet cold galvanizing from mixing and contaminating the grease. If grease is applied before cold galvanizing, the grease will contaminate the coated surface of the cold galvanizing, leading to decreased adhesion and reduced corrosion resistance; simultaneously, the wet cold galvanizing will also contaminate the grease, affecting its lubrication effect.

[0072] In one exemplary embodiment, the wind turbine blade corrosion protection method of this disclosure further includes: determining in advance the exposed section of the unthreaded portion of the blade root bolt after installation based on the installation design parameters of the blade root bolt, and applying cold galvanizing to the target exposed section near the second threaded end of the exposed section for corrosion protection.

[0073] For example, the exposed section of the unthreaded portion after installation refers to the portion of the unthreaded portion exposed to the atmosphere on the outer side of the flange end face after the first threaded end of the blade root bolt is screwed into the mounting hole on the flange end face of the blade root according to step S120 and adjusted to the first preset length (i.e., 363±1mm). Installation design parameters may also include the total length of the bolt extending beyond the flange end face, the chamfer depth of the mounting hole, the boss height of the flange end face, and the installation position of the gasket. The unthreaded portion from the outer surface of the flange end face to the final installation position of the gasket is the exposed section of the unthreaded portion of the blade root bolt after installation. The target exposed section refers to the portion of the exposed section closest to the second threaded end. More specifically, the target exposed section refers to the unthreaded portion of the exposed section adjacent to the non-engaging section of the second threaded end. The length of the target exposed section can be half of the entire exposed section, or it can be determined based on experience or actual conditions; this exemplary embodiment does not impose any special limitations on this.

[0074] In one exemplary embodiment, the wind turbine blade corrosion prevention method of this disclosure further includes: applying cold galvanizing to the damaged portion of the unthreaded part of the blade root bolt for corrosion prevention treatment.

[0075] For example, one can check whether there is any damage to the exposed section of the unthreaded part other than the target exposed section. If so, cold galvanizing can be applied to the damaged area.

[0076] In one exemplary embodiment, the wind turbine blade corrosion prevention method of this disclosure further includes: applying sealant to the blade root flange for corrosion prevention treatment; wherein, the method of applying sealant to the blade root flange includes at least one of the following: applying sealant to the blade root flange before the blade is removed from the tooling, or applying sealant to the blade root flange after the blade is lifted off the blade lifting vehicle.

[0077] For example, sealant can also be applied to the flange at the blade root for corrosion protection. This can be done by lifting the blade from a jig, applying sealant to the blade root flange before the blade is removed from the jig, or by lifting the blade from a blade lifter, applying sealant to the blade root flange after the main crane has lifted the blade off the lifter.

[0078] In one exemplary scenario, the tooling bolts for blade transport need to be replaced with blade root bolts before hoisting. These tooling bolts can be removed using an Allen wrench. Threadlocker can be applied to the short thread end of the blade root bolt, starting from the bolt end face and extending to half the length of the embedded thread. Allow it to dry completely. Then, place an O-ring on the unthreaded portion of the bolt at half its length and screw the bolt into the mounting hole (the O-ring should not protrude from the mounting hole). The bolt should protrude 363±1mm from the flange end face. Next, seal the gap between the bolt and the mounting hole with sealant, ensuring the sealant does not extend beyond the flange end face. Clean off any excess sealant with a cloth. When applying sealant, avoid getting it on the connecting bolt threads. If sealant is accidentally applied to the threads, wipe it off immediately with a cloth, as this will affect the installation of the blade nuts. Finally, perform secondary anti-corrosion segmented treatment on the blade root bolts. Specifically, first, thoroughly stir the cold galvanizing solution. After the blade is removed from the blade transport vehicle or blade fixture, evenly apply cold galvanizing to the threads of the blade bolts near the polished rod (where they are not engaged with the nut) and part of the polished rod. Apply only bolt grease to the threads engaged with the nut and the exposed threads, without applying cold galvanizing. Follow the specifications of the blade root bolts accordingly. Figure 4 Apply the galvanizing solution in the indicated sections, explicitly prohibiting the application of cold galvanizing to the threaded engagement area. Next, inspect the smooth bolt shaft for any dents or damage, and apply cold galvanizing evenly to any damaged areas. The application of cold galvanizing requires the same precision as bolt grease: it must be applied evenly and completely to the corresponding areas. Furthermore, bolt grease should only be applied after the cold galvanizing process has completely dried.

[0079] exist Figure 4 In the diagram, 41 is the interior of the blade root, 42 is the interior of the pitch bearing, 43 is the cold-galvanized coating section (i.e., the non-engaging section of the second threaded end of the blade root bolt and the area near the non-engaging section of the unthreaded portion of the blade root bolt), 44 is the bolt grease coating section (i.e., the engaging section of the second threaded end and the cross-section of the second threaded end), 45 is a washer, and 46 is a nut. The cold-galvanized coating section 43 has a dimension of 80mm, and the bolt grease coating section 44 has a dimension of 83mm.

[0080] In this disclosure, structural sealing is performed first, providing a bolt structure with O-rings and a sealant sealing process to establish a physical sealing barrier for the bolt holes at the leaf roots, thereby achieving long-term corrosion protection. Next, surface treatment is performed, specifically, a segmented and sequential process of "corrosion protection first (cold galvanizing), then lubrication (grease)." Based on the sealing and corrosion protection, the bolt body undergoes refined surface treatment to reconcile corrosion protection requirements with the friction coefficient requirements during installation.

[0081] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0082] It should be understood that this disclosure is not limited to the specific methods, steps, or structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. Those skilled in the art will readily conceive of other embodiments based on the specific implementations provided in this disclosure. Therefore, the specific implementations provided in this disclosure are merely exemplary, and the scope and spirit of this disclosure are indicated by the claims, and should cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary technical means in the art not disclosed in this disclosure.

Claims

1. A method for corrosion protection of wind turbine blades, characterized in that, include: Apply thread-locking agent to the first threaded end of the blade root bolt of the wind turbine, and place a circular sealing ring at the first preset position of the unthreaded part of the blade root bolt; Screw the first threaded end into the mounting hole on the flange end face at the root of the blade, and ensure that the circular sealing ring is not exposed outside the mounting hole; Use sealant to seal the gap between the blade root bolt and the mounting hole; The second threaded end of the blade root bolt is segmented, and the segmentation process includes anti-corrosion treatment and lubrication treatment.

2. The method according to claim 1, characterized in that, The application of thread-locking agent to the first threaded end of the blade root bolt of the wind turbine includes: Apply threadlocking agent to the area encompassed from the end face of the first thread to halfway down the first thread.

3. The method according to claim 1, characterized in that, The sealant is applied to the gap between the blade root bolt and the mounting hole, without extending beyond the flange end face of the blade root.

4. The method according to claim 1, characterized in that, The step of screwing the first threaded end into the mounting hole on the blade root flange end face includes: Screw the first threaded end into the mounting hole on the blade root flange end face, and make the blade root bolt extend out of the blade root flange end face by a first preset length.

5. The method according to claim 4, characterized in that, The first preset length is determined based on the total thickness of the hub-side components to be connected by the leaf root bolt and the safety clearance required for installation.

6. The method according to claim 1, characterized in that, The segmentation process for the second threaded end of the blade root bolt includes: Based on the installation design parameters of the blade root bolt, the non-engaging section that does not engage with the nut in the second threaded end of the blade root bolt is determined, and the non-engaging section is coated with cold galvanizing for corrosion protection. Lubricating grease is applied to the meshing section of the second threaded end of the leaf root bolt that contacts the nut for lubrication.

7. The method according to claim 6, characterized in that, The grease is applied after the cold galvanizing process has dried.

8. The method according to claim 6, characterized in that, The method further includes: Based on the installation design parameters of the blade root bolt, the exposed section of the unthreaded part of the blade root bolt after installation is determined in advance, and the target exposed section near the second thread end of the exposed section is coated with cold galvanizing for corrosion protection.

9. The method according to claim 1, characterized in that, The method further includes: Cold galvanizing is applied to the damaged areas of the unthreaded portion of the blade root bolt for corrosion protection.

10. The method according to claim 1, characterized in that, The method further includes: applying sealant to the blade root flange for corrosion protection; wherein, the method of applying sealant to the blade root flange includes at least one of the following: applying sealant to the blade root flange before the blade is removed from the tooling, or applying sealant to the blade root flange after the blade is lifted off the blade lifting vehicle.

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