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US-12624677-B2 - Reinforcement of a wind turbine blade

US12624677B2US 12624677 B2US12624677 B2US 12624677B2US-12624677-B2

Abstract

The present invention provides a to method for reinforcing a wind turbine blade, such as a root end. The root end comprises a first and a second bushing for attaching the wind turbine blade to a wind turbine hub, the bushings being located between an inner sidewall of the root end and an outer sidewall of the root end, the bushings being separated by retaining material, the method comprising forming a first injection channel in the retaining material; forming a first pressure release channel in the first retaining material, wherein the first pressure release channel is formed to be in fluid communication with the first injection channel in a region between the inner sidewall and the outer sidewall; and injecting adhesive material into the first injection channel at least until adhesive material enters the formed first pressure release channel. The invention also provides a wind turbine blade having a root end that has been reinforced using such a method. Further aspects are provided.

Inventors

  • Lars JUHL
  • Jesper Hasselbelch GARM
  • Danial Ashouri VAJARI
  • Steen MORTENSEN

Assignees

  • LM WIND POWER A/S

Dates

Publication Date
20260512
Application Date
20220125
Priority Date
20210125

Claims (20)

  1. 1 . A method for reinforcing a root end ( 16 ) of a wind turbine blade, the root end ( 16 ) comprising a plurality of bushings ( 311 , 312 ) for attaching the wind turbine blade ( 10 ) to a wind turbine hub ( 8 ), each bushing being located between an inner sidewall ( 405 ) of the root end and an outer sidewall ( 406 ) of the root end ( 16 ), the plurality of bushings being mutually separated by retaining material ( 301 , 302 , 303 ), a first bushing ( 311 ) and a second bushing ( 312 ) of the plurality of bushings ( 311 , 312 ) being separated by first retaining material ( 301 ), the method comprising: (i) forming a first injection channel ( 561 , 661 ) in the first retaining material ( 301 ), (ii) forming a first pressure release channel ( 562 , 662 ) in the first retaining material ( 301 ), wherein the first pressure release channel ( 562 , 662 ) is formed to be in fluid communication with the first injection channel ( 561 ) in a region between the inner sidewall ( 405 ) and the outer sidewall ( 406 ), and (iii) injecting adhesive material ( 571 , 671 ) into the first injection channel ( 561 ) at least until adhesive material enters the formed first pressure release channel ( 562 ).
  2. 2 . The method in accordance with claim 1 , wherein the first injection channel and the first pressure release channel are formed through a first sidewall ( 405 , 406 ) of the root end, wherein the first sidewall is the inner sidewall ( 405 ) or the outer sidewall ( 406 ) of the root end.
  3. 3 . The method in accordance with claim 1 , wherein the first injection channel and/or the first pressure release channel is formed through a blade mounting interface ( 307 ) of the root end.
  4. 4 . The method in accordance with claim 1 , further comprising a step of inserting an injection packer ( 870 ) into the first injection channel ( 561 ) before the step of injecting adhesive material into the first injection channel ( 561 ).
  5. 5 . The method in accordance with claim 1 , wherein the first retaining material ( 301 ) comprises a pultruded fibre-reinforced composite element.
  6. 6 . The method in accordance with claim 1 , wherein the adhesive material is provided at least until adhesive material entirely fills the first pressure release channel ( 562 ).
  7. 7 . The method in accordance with claim 1 , further comprising repeating step (i) one or more times to provide corresponding one or more additional injection channels ( 661 , 761 ) ( 661 , 761 ) for injecting adhesive material.
  8. 8 . The method in accordance with claim 1 , further comprising repeating step (ii) one or more times to provide corresponding one or more additional pressure release channels ( 662 , 762 ), the one or more additional pressure release channels being formed to be in fluid communication with the first injection channel ( 561 ) and/or with an additional injection channel ( 661 , 761 ).
  9. 9 . The method in accordance with claim 2 , wherein the first injection channel ( 561 ) is in fluid communication with a cavity ( 351 , 352 , 353 ) located between the first sidewall ( 405 ) and a second sidewall ( 406 ).
  10. 10 . The method in accordance with claim 2 , wherein the first injection channel ( 561 ) is in fluid communication with a cavity ( 351 ) located between the first sidewall ( 405 ) and the first retaining material ( 301 ).
  11. 11 . The method in accordance with claim 1 , wherein the first injection channel ( 561 ) is in fluid communication with a cavity ( 352 ) located between the first retaining material ( 301 ) and the first bushing ( 311 ).
  12. 12 . The method in accordance with claim 11 , wherein the first injection channel is aimed towards a first point ( 1352 ) of the first bushing ( 311 ), a distance between the inner sidewall and the first point of the first bushing being in the range 0.3-0.7 times a distance (D) between the inner sidewall ( 405 ) and the outer sidewall ( 406 ) at a location of the first point ( 1352 ).
  13. 13 . The method in accordance with claim 1 , wherein the first injection channel ( 561 ) is in fluid communication with a cavity ( 353 ) located between the second sidewall ( 406 ) and the first retaining material ( 301 ).
  14. 14 . The method in accordance with claim 1 , further comprising: locating a first cavity between the inner sidewall ( 405 ) and the outer sidewall ( 406 ) by use of ultrasound equipment, the first injection channel ( 561 ) then being formed in fluid communication with the first cavity to allow injection of adhesive material into the first cavity, the first pressure release channel ( 562 ) being formed in fluid communication with the first cavity.
  15. 15 . The method in accordance with claim 1 , wherein the first injection channel ( 561 ) is formed near a first end of the first bushing ( 311 ), the method further comprising performing step (i) at a location near a second end of the first bushing ( 311 ), thereby forming a corresponding second injection channel ( 761 ) near the second end of the first bushing.
  16. 16 . The method in accordance with claim 1 , wherein the first injection channel ( 561 , 761 ) is formed within a distance of 150 mm from a first end of the first bushing ( 311 ) and/or a second end of the first bushing ( 311 ).
  17. 17 . The method in accordance with claim 1 , wherein the method is performed while the wind turbine blade is attached to a hub ( 8 ) of a wind turbine.
  18. 18 . The method in accordance with claim 17 , further comprising: (iv) prior to steps (i) to (iii), monitoring a specific part of the root end between the inner sidewall ( 405 ) and the outer sidewall ( 406 ) using ultrasound measuring equipment providing a corresponding ultrasound measurement, (v) based on the ultrasound measurement obtained in step (iv), determining that a defect has formed in the specific part of the root end, and (vi) reinforcing the specific part of the root end ( 16 ) in response to determining that the defect has formed.
  19. 19 . The method in accordance with claim 18 , wherein the monitoring is performed automatically by the ultrasound measurement equipment.
  20. 20 . The method in accordance with claim 18 , wherein the ultrasound measurement is transmitted to a first remote location and the determining that a defect has formed is determined at the first remote location.

Description

This is a National Phase Application filed under 35 U.S.C. 371 as a national stage of PCT/EP2022/051640, filed Jan. 25, 2022, an application claiming the benefit of British Application No. 2100935.2, filed Jan. 25, 2021, the content of each of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The present invention relates to a root end of a wind turbine blade, in particular to a method of reinforcement of such a root end and to a wind turbine blade with a reinforced root end. BACKGROUND The root end of a wind turbine blade allows firm and secure attachment of the blade to the hub of a wind turbine. Manufacturing of a root end may for instance include laying up a number of layers of a fibre material inside a mould to form an outer skin. Then, a plurality of fastening elements is positioned relative to the mould and the outer skin fibre layers, resulting in an outer sidewall after resin infusion. Individual fastening elements are connected to a root end plate holding them in place during manufacturing. A plurality of retaining members is afterwards positioned between the individual fastening members. Further layers of the fibre material are laid up over the fastening and retaining members to form an inner skin, resulting in an inner sidewall after resin infusion. The structure is then enclosed by a bag material, and resin is introduced using vacuum infusion. The resin is finally cured, whereby a first wind turbine blade shell part is formed. A second wind turbine blade shell part is manufactured in a similar manner, after which the two wind turbine blade parts are attached to one another, typically by gluing. The fastening elements in a wind turbine blade for attaching the blade to the wind turbine hub typically comprise a bushing assembly in the root end of the wind turbine blade. Both during blade manufacturing and during operation, defects may form. For instance, a bushing may dislodge from the retaining material, whereby a gap is formed. Such defects in the root end may potentially lead to critical failure of the blade. Other parts of a wind turbine blade may also need reinforcement, including while the blade is attached to a wind turbine hub, which involves a high risk to personnel. SUMMARY OF THE INVENTION The inventors have realised that there may arise a need for reinforcing root ends of wind turbine blades by eliminating gaps near root end bushings in the root, formed for instance while the blades are attached to a wind turbine hub or existing even before a blade has ever been attached to a wind turbine hub. In a first aspect, the invention provides a method for reinforcing a root end of a wind turbine blade, the root end comprising a plurality of bushings for attaching the wind turbine blade to a wind turbine hub, each bushing being located between an inner sidewall of the root end and an outer sidewall of the root end, the plurality of bushings being mutually separated by retaining material, a first bushing and a second bushing of the plurality of bushings being separated by first retaining material, the method comprising: (i) forming a first injection channel in the first retaining material,(ii) forming a first pressure release channel in the first retaining material, wherein the first pressure release channel is formed to be in fluid communication with the first injection channel in a region between the inner sidewall and the outer sidewall, and(iii) injecting adhesive material into the first injection channel at least until adhesive material enters the formed first pressure release channel. The injection channel is formed such that adhesive can be communicated to a region between the inner sidewall and the outer sidewall of the root end. The pressure release channel is in fluid communication with the injection channel to allow the adhesive to flow as desired. The adhesive will flow through a path of least resistance, and thus the channels are provided such that the adhesive flows to the desired location. The first injection channel and the first pressure release channel may be formed at a same longitudinal position along a longitudinal axis of the first bushing, or they may be formed at different longitudinal positions along the longitudinal axis of the first bushing. In embodiments where further injection channel(s) and/or pressure release channel(s) are formed, the respective longitudinal positions may coincide or not. Some channels may have been formed at the same longitudinal position, others at different longitudinal positions. In some embodiments, a width of the first injection channel is in the range 3-8 mm, such as in the range 5-7 mm, such as 6 mm. In some embodiments, a width of the first pressure release channel is in the range 2-6 mm, such as in the range 3-5 mm, such as 4 mm. In some embodiments, at least a part of the adhesive material is injected with a pressure of at least 50 bar, such as at least 100 bar, such as at least 200 bar, such as at least 400 ba