A reinforcement method for preventing offshore wind turbine blade tips from salt spray corrosion and shedding

Abstract

This invention discloses a method for reinforcing offshore wind turbine blade tips to prevent them from falling off due to salt spray corrosion. The main steps involve wrapping a reinforcement layer around the blade tip using hand lay-up. After heating and curing, holes are punched and fiberglass rods are inserted to secure the blade tip, preventing it from falling off. The reinforced blade tip is securely fixed, has a long operating life, is resistant to salt spray corrosion, and can still be secured even if the bonding area completely fails.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine blade production, and in particular to a method for reinforcing offshore wind turbine blade tips to prevent them from salt spray corrosion and shedding. Background Art

[0002] Wind energy is a usable form of energy provided to humans by airflow. It is abundant, widely distributed, and clean, making it a renewable energy source. Wind turbine blades are the core components of wind turbines, converting natural wind energy into electricity. Currently, blade tips are primarily bonded using a specialized adhesive with a width of 80-100mm. The blade tips are made of metal, and the rough surface is sandblasted. The bonding method involves applying a mixed adhesive to a thickness of 8-10mm to the windward surface. The sandblasted metal blade tip is then positioned and pressurized using a specialized tip positioning tool, followed by heat curing. Currently, offshore wind farms are often built in areas prone to lightning strikes. High humidity allows lightning to travel through bolts and reach the blade tips, drawing energy into corroded milled gaps, causing separation between the fiberglass and metal blade tips. Furthermore, the high concentration of corrosive components in the offshore atmosphere makes the metal blade tips susceptible to salt spray corrosion and subsequent detachment. Currently, there is a lack of clear reinforcement methods. Therefore, it is necessary to provide a method for reinforcing and repairing blades in offshore wind farms or pre-reinforcement when producing blades for offshore wind farms. Summary of the Invention

[0003] In response to the above technical problems, the present invention provides a reinforcement method for preventing the blade tips of offshore wind turbine blades from salt spray corrosion and falling off, which is simple to operate, firmly fixes the blade tips, is resistant to salt spray corrosion, and has a strong fixing effect.

[0004] To solve the above technical problems, the present invention provides a method for reinforcing the blade tip of an offshore wind turbine blade to prevent salt spray corrosion and shedding, comprising the following steps:

[0005] ① Starting from the silicone seam, measure the bonding area of the leaf tip on the blade and mark it.

[0006] ② Grind the bonding area and silicone seam of the blade tip on the windward side and the leeward side of the blade, and grind a rough surface around the blade. The width of the rough surface is not less than the marked position.

[0007] ③ For the blade winding reinforcement layer, use unidirectional glass fiber cloth and soak it in epoxy hand-layup resin glue; fit the middle part of the unidirectional glass fiber cloth to the mold seam of the leading edge of the blade, then fit it to the windward and leeward sides of the blade, wrap it to the trailing edge, and then use a clamp to fix the two ends of the unidirectional glass fiber cloth. Repeat the winding until 3-5 layers of unidirectional glass fiber cloth are wrapped. The width of the reinforcement layer is the same as the width of the bonding area. Use the clamp to clamp it again after each layer of unidirectional glass fiber cloth is wrapped. After the reinforcement layer is dry, remove the clamp and perform polishing and shaping.

[0008] ④ Make a punched reinforcement area, starting from the mold seam of the trailing edge of the blade, use biaxial glass fiber cloth, impregnate it with epoxy hand-lay-up resin glue, and hand-lay the glass fiber cloth from the upwind and leeward sides to the leading edge respectively, wrap it around, and then use a clamp to fix the two ends of the unidirectional glass fiber cloth, and repeat the winding until the upwind and leeward sides of the blade are wrapped with 2-3 layers of biaxial glass fiber cloth. Use the clamp to re-clamp each time a layer of biaxial glass fiber cloth is wrapped. After the punched reinforcement area is dry, remove the clamp and perform grinding and shaping.

[0009] ⑤ The punched reinforcement area is heated and cured at a temperature of 65°C to 80°C. The glass fiber reinforced plastic conversion temperature TG value is required to be consistent with the blade maintenance requirement value.

[0010] ⑥ After the glass fiber reinforced plastic transition temperature TG value in step ⑤ is tested to be qualified, several through holes are drilled at the blade tip bonding area.

[0011] ⑦ Insert the glass fiber rod coated with adhesive into the through hole so that both ends of the glass fiber rod are exposed on the windward and leeward sides. After the glass fiber rod and the blade are cured, grind the exposed glass fiber rods on the windward and leeward sides to make them smooth.

[0012] ⑧ Use silicone to fill the silicone seam to form a sealing layer.

[0013] Furthermore, in step ②, if the blade is in an installed state, the paint surface of the blade tip bonding area is first polished, and the silicone in the silicone seam is cleaned.

[0014] Furthermore, the number of winding layers of the unidirectional glass fiber cloth in step ③ is 4 layers, and the number of hand-layup layers of the biaxial glass fiber cloth in step ④ is 3 layers.

[0015] Furthermore, in the step ③, the glue content of the unidirectional glass fiber cloth after impregnation is 45%-55%, and in the step ④, the glue content of the biaxial glass fiber cloth after impregnation is 45%-55%.

[0016] Furthermore, in step ②, the axial width of the rough surface is not less than the marked position; in step ③, the axial width of the reinforcement layer is the same as the axial width of the bonding area; in step ④, the axial width of the punched reinforcement area is the same as the axial width of the reinforcement layer, and the punched reinforcement area completely covers the reinforcement layer.

[0017] Furthermore, in step ⑤, the heating time is not less than 3 hours.

[0018] Furthermore, in step ⑤, the number of sampling points for TG value testing in the punched reinforcement area is at least 5.

[0019] Furthermore, in step ⑥, three positioning blocks are bonded to the windward surface, a punching tool is fixed by the positioning blocks, and holes are drilled using the punching tool.

[0020] Furthermore, after step ⑦ is completed, the chamfer is ground at the connection between the punched reinforcement area and the blade.

[0021] Furthermore, in step ⑧, after the silicone seam is filled with silicone, the chamfer is scraped out.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The present invention adopts a method of wrapping a reinforcement layer around the tip of a wind turbine blade and inserting a glass fiber rod by punching a hole, and using the glass fiber rod to reinforce the blade tip. The reinforced blade tip is firmly fixed, has a long operating time, and is resistant to salt spray corrosion. Even if the bonding area completely fails, the blade tip can still be fixed. This method can be applied to offshore wind farms to determine the blades to be repaired, and can also pre-reinforce blades that are being produced and need to be installed in offshore wind farms, which can prevent the blade tips from falling off in advance and also reduce maintenance costs.

[0024] 2. For blades installed in offshore wind farms, the present invention is easy to operate and convenient for high-altitude operations in wind farms; the operation efficiency is high and the downtime is short. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention.

[0026] Figure 2 It is a schematic cross-sectional view of the AA position of the present invention.

[0027] Figure 3 Schematic diagram of the bonding area of the present invention.

[0028] In the figure: 1. Blade, 2. Reinforcement layer, 3. Silicone seam, 4. Blade tip, 5. Through hole, 6. Bonding area. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below with reference to the accompanying drawings and embodiments:

[0030] The embodiments of the present invention are as follows:

[0031] Example 1: Figure 1 、 Figure 2 、 Figure 3 A method for reinforcing the tip of an offshore wind turbine blade to prevent salt spray corrosion and shedding is shown, and mainly includes the following steps:

[0032] ① Starting from the silicone seam 3, measure the bonding area 6 of the blade tip 4 on the blade 1 and mark it.

[0033] ② Grind the bonding area 6 and the silicone seam 3 of the blade tip 4 on the windward and leeward sides of the blade 1, and grind a rough surface around the blade 1. The axial width of the rough surface is not less than the marked position.

[0034] ③ Wrap the reinforcement layer 2 around the blade 1, use unidirectional glass fiber cloth, and soak it in epoxy hand-layup resin glue so that the glue content of the unidirectional glass fiber cloth after soaking is 45%-55%; fit the middle part of the unidirectional glass fiber cloth to the mold seam of the leading edge of the blade 1, and then fit it to the windward and leeward sides of the blade 2, wrap it to the trailing edge, and then use a clamp to fix the two ends of the unidirectional glass fiber cloth. Repeat the winding until 4 layers of unidirectional glass fiber cloth are wrapped. The axial width of the reinforcement layer 2 is the same as the axial width of the bonding area 6. Use the clamp to clamp it again after each layer of unidirectional glass fiber cloth is wrapped. After the reinforcement layer is dry, remove the clamp and perform grinding and shaping.

[0035] Among them, the gram weight of unidirectional glass fiber cloth is 600g / m 2 .

[0036] ④ Make a punched reinforcement area. Take the mold seam at the trailing edge of blade 1 as the starting point, use biaxial glass fiber cloth, and soak it in epoxy hand lay-up resin glue to make the number of hand lay-up layers of biaxial glass fiber cloth 3. Hand lay up the glass fiber cloth from the upwind and leeward sides to the leading edge respectively, wrap it around for a circle, and then use a clamp to fix the two ends of the unidirectional glass fiber cloth. Repeat the winding until the upwind and leeward sides of blade 1 are wrapped with 3 layers of biaxial glass fiber cloth. Use the clamp to re-clamp each time a layer of biaxial glass fiber cloth is wrapped. After the reinforcement layer is dry, remove the clamp and grind it for shaping. The axial width of the punched reinforcement area is the same as the axial width of the reinforcement layer 2, and the punched reinforcement area completely covers the reinforcement layer.

[0037] Among them, the weight of biaxial glass fiber cloth is 808g / m 2 .

[0038] ⑤ Use a hot air gun or electric blanket to heat and cure the punched reinforcement area at a temperature of 65°C to 80°C for more than 3 hours, so that the FRP conversion temperature TG value is greater than or equal to 65°C.

[0039] ⑥ Select 5 test sampling points in the punched reinforcement area, use tools to chisel samples at the test sampling points to test the TG value. The qualified standard for the TG value is higher than 65℃. If the TG value of one of the samples is less than 65℃, grind and clean the punched reinforcement area and the reinforcement layer 2, and repeat step ①. If the TG value of the 5 samples is greater than or equal to 65℃, bond 3 positioning blocks to the windward side, fix the punching tool through the positioning blocks, and use the punching tool to drill several through holes 5 at the bonding area 6 of the blade tip 4.

[0040] The diameter of the through hole is φ6.2 mm, and the number of the through holes is not limited, as long as the blade tip 4 can be fixed.

[0041] Drilling examples using a 52.3m blade:

[0042]

[0043] ⑦ Insert the glass fiber rod coated with adhesive into the through hole 5 so that both ends of the glass fiber rod are exposed on the windward and leeward sides. After the glass fiber rod and the blade 1 are cured, grind the exposed glass fiber rods on the windward and leeward sides to make them smooth.

[0044] Among them, the diameter of the glass fiber rod is φ6mm.

[0045] ⑧ Use silicone to fill the silicone seam 3, scrape out the chamfers, and form a sealing layer.

[0046] Example 2: The difference between this example and Example 1 is that: for blades that have been installed and are found to need reinforcement and maintenance, the wind turbine is first shut down, and then the maintenance personnel use tools to grind the paint surface of the reinforcement area and clean the silicone in the silicone seam 3. After the paint surface of the reinforcement area is completely removed, the same operation as in Example 1 is performed. After completion, the blades are painted, and the paint specifications are the same as the paint specifications marked in the production instructions of the reinforced blades.

[0047] It should be noted that experiments have shown that drilling and reinforcing the tips of wind turbine blades will not have a significant impact on resistance and will not affect their lightning protection effects.

[0048] The above embodiments are intended to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be included in the scope of the claims of the present invention.

Claims

1. A method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding, characterized by: The following steps are involved: ① Taking the silicone seam (3) as the starting point, measure the bonding area (6) of the blade tip (4) on the blade (1) and mark it; ② Grinding the bonding area (6) and the silicone seam (3) of the blade tip (4) on the windward side and the leeward side of the blade (1), and grinding a rough surface around the blade (1); ③ Wrapping the reinforcement layer (2) around the blade (1) uses unidirectional glass fiber cloth soaked in epoxy hand-lay-up resin glue; fitting the middle of the unidirectional glass fiber cloth to the mold seam of the leading edge of the blade (1), then fitting it to the windward and leeward sides of the blade (1), wrapping it to the trailing edge, and then using a clamp to fix both ends of the unidirectional glass fiber cloth, repeating the wrapping until 3-5 layers of unidirectional glass fiber cloth are wrapped, and re-clamping the clamp each time a layer of unidirectional glass fiber cloth is wrapped. After the reinforcement layer is dried, the clamp is removed and polished and reshaped; ④ Make a punching reinforcement area, using the mold seam of the trailing edge of the blade (1) as the starting point, using biaxial glass fiber cloth, soaking it in epoxy hand lay-up resin glue, and hand lay-up the glass fiber cloth from the windward and leeward sides to the leading edge, wrapping it around, and then using a clamp to fix the two ends of the biaxial glass fiber cloth, and repeating the wrapping until the windward and leeward sides of the blade (1) are both wrapped with 2-3 layers of biaxial glass fiber cloth, and using the clamp to re-clamp it once each time a layer of biaxial glass fiber cloth is wrapped, and after the punching reinforcement area is dried, remove the clamp and perform grinding and shaping; 5. The punched reinforcement area is heated and cured at a temperature of 65° C. to 80° C. The glass fiber reinforced plastic conversion temperature TG value is required to be consistent with the maintenance requirement value of the blade (1); ⑥ After the glass fiber reinforced plastic transition temperature TG value in step ⑤ is tested to be qualified, a plurality of through holes (5) are drilled at the bonding area (6) of the blade tip (4); ⑦ Insert the glass fiber rod coated with adhesive into the through hole (5) so that both ends of the glass fiber rod are exposed on the windward and leeward sides. After the glass fiber rod and the blade (1) are solidified, grind the glass fiber rod exposed on the windward and leeward sides to make them smooth; ⑧ Use silica gel to fill the silica gel seam (3) to form a sealing layer.

2. The method for reinforcing the tip of an offshore wind turbine blade to prevent salt spray corrosion and shedding according to claim 1, characterized in that: In step ②, if the blade (1) is in the installed state, the paint surface of the bonding area of the blade tip (4) is first polished, and the silicone in the silicone seam (3) is cleaned.

3. The method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding according to claim 1, characterized in that: The number of winding layers of the unidirectional glass fiber cloth in step ③ is 4 layers, and the number of hand-laying layers of the biaxial glass fiber cloth in step ④ is 3 layers.

4. The method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding according to claim 1, characterized in that: In the step ③, the glue content of the unidirectional glass fiber cloth after soaking is 45%-55%. In the step ④, the glue content of the biaxial glass fiber cloth after soaking is 45%-55%.

5. The method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding according to claim 1, characterized in that: In step ②, the axial width of the rough surface is not less than the marked position; in step ③, the axial width of the reinforcing layer (2) is the same as the axial width of the bonding area (6); in step ④, the axial width of the punched reinforcing area is the same as the axial width of the reinforcing layer (2), and the punched reinforcing area completely covers the reinforcing layer (2).

6. The method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding according to claim 1, characterized in that: In step ⑤, the heating time is not less than 3 hours.

7. The method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding according to claim 1, characterized in that: In step ⑤, the number of sampling points for TG value testing in the punched reinforcement area is at least 5.

8. The method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding according to claim 1, characterized in that: In step ⑥, three positioning blocks are bonded to the windward side, a punching tool is fixed by the positioning blocks, and holes are drilled using the punching tool.

9. The method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding according to claim 1, characterized in that: After step ⑦ is completed, the chamfer is ground at the connection between the punched reinforcement area and the blade (1).

10. The method for reinforcing offshore wind turbine blade tips to prevent salt spray corrosion and shedding according to claim 1, characterized in that: In step ⑧, after the silicone seam (3) is filled with silicone, the chamfer is scraped out.

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