Wind turbine blade

• US 20040253114A1
• Filed: 08/13/2004
• Published: 12/16/2004
• Est. Priority Date: 07/19/2001
• Status: Active Grant

• Current Assignee: Vestas Wind Systems A/S
• Original Assignee: Vestas Wind Systems A/S
• Inventors: Barlow, Nicholas Duduley, Hancock, Mark, Vronsky, Tomas, Gunneskov, Ole
• Granted Patent: US 7,198,471 B2
• Time in Patent Office: Days
• US Class Current: 416/224
• CPC Class Codes: B29C 70/443 and impregnating by vacuum or injection
• CPC Class Codes: B29C 70/52 Pultrusion, i.e. forming and compressing by continuously pulling through a die
• CPC Class Codes: F03D 1/065 characterised by their construction elements F03D13/10 takes precedence
• CPC Class Codes: F03D 1/0675 of the blades
• CPC Class Codes: F05B 2240/30 Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The invention relates to a wind turbine blade comprising a number of pre-fabricated strips arranged in a sequence along the outer periphery. The strips consist of a fibrous composite material, preferably carbon fibres, and consist of a wooden material, preferably plywood or wooden fibres held in a cured resin. The advantage is that it is possible to manufacture blades for wind turbines which are very stiff and generally have a high strength, but which nevertheless are easy to manufacture and also is much cheaper to manufacture compared to conventional manufacturing techniques. The invention also relates to methods for manufacturing prefabricated strips and for manufacturing wind turbine blades.

Claims

1-23. -23. Canceled.

24. A blade for a wind turbine, wherein a blade, which over a part extending over at least a third of the total length from tip to hub comprises a layer along an outer periphery of the cross-section of the blade, and wherein the layer at least partly is constituted by a number of pre-fabricated pultruded strips of a fibrous composite material arranged in a sequence along the outer periphery.

25. A blade according to claim 24, wherein the strips of the outer layer are jointed by means of resin infusion.

26. A blade according to claim 25, wherein the strips of the outer layer are jointed by means of vacuum infusion of a resin.

27. A blade according to claim 24, wherein at least some of the pre-fabricated pultruded strips are constituted by hollow tubes formed from a fibrous composite material.

28. A blade according to claim 26, wherein at least some of the pre-fabricated pultruded strips are constituted by hollow tubes formed from a fibrous composite material.

29. A blade according to claim 27, wherein the fibrous composite material comprises a fibre volume fraction from 50% to 90%.

30. A blade according to claim 27, wherein the pultruded strips have a pultrusion direction substantially aligned with a longitudinal direction of the blade.

31. A blade according to claim 30, wherein the fibrous composite material comprises a carbon fibre volume fraction from 50% to 90%.

32. A blade according to claim 30, wherein the fibrous composite material comprises a fibre volume fraction from 50% to 90%.

33. A blade according to claim 32, wherein the fibrous composite material comprises a fibre volume fraction of from 60% to 80%.

34. A blade according to claim 32, wherein the fibrous composite material comprises a carbon fibre volume fraction from 50% to 90%.

35. A blade according to claim 34, wherein the fibrous composite material comprises a fibre volume fraction of from 60% to 80%.

36. A blade according to claim 24, wherein the layer at least partly is constituted by a number of strips made from a wooden material arranged in a sequence along the outer periphery.

37. A blade according to claim 36, wherein the wooden material is plywood.

38. A blade according to claim 36, wherein the wooden material is comprised by wooden fibres held in a cured resin.

39. A blade according to claim 36, wherein the layer at least partly is constituted by strips of a wooden material and strips of a fibrous composite material in a sequence along the outer periphery.

40. A blade according to claim 39, wherein said sequence is an alternating sequence of strips of a wooden material and strips of a fibrous composite material.

41. A blade according to claim 24, wherein said layer is enclosed in an outer shell and an inner shell made from a fibrous composite material.

42. A blade according to claim 24, wherein load measuring fibres is enclosed in either one or both of the outer shell and the inner shell.

43. A blade according to claim 42, wherein the load measuring fibres are optical fibres being additional to, alternatively being substitute to, the reinforcing fibres.

44. A blade according to claim 42, wherein the load measuring fibres are carbon fibres being additional to, alternatively being substitute to, the reinforcing fibres.

45. A blade according to claim 24, wherein lightning protection means comprising lightning attractors are incorporated into either one or both of the shells.

46. A blade according to claim 45, where the lightning attractors are connected to a width of metal mesh or similar material extending over the fibre reinforced area of the shells.

47. A blade according to claim 24, wherein a radio frequency absorption medium is incorporated into either one or both of the shells.

48. Method for manufacturing a pre-fabricated strip for a blade according to claim 24, said blade comprising a layer material arranged along an outer periphery of the cross-section of the blade, and said method involving the following steps:

assembling at least two individual materials to constitute the pre-fabricated strip

selecting at least one of the at least two individual materials among fibrous composite materials

inserting the assembled at least two individual material into a container such as a bag

evacuating the container, infusing a curing resin, and allowing the resin to cure, and

taking out from the container the assembled and cured strip thus fabricated.

49. Method for manufacturing a shell for a blade according to claim 24, said shell comprising a layer material arranged along an outer periphery of the cross-section of the shell, said layer comprising pre-fabricated strips, and said method involving the following steps:

applying a surface material, preferably gel coat, to a mould for the blade

optionally applying a metal mesh, a glass fibre mesh and any transfer media-assembling at least two individual materials to constitute the pre-fabricated strips

selecting at least one of the at least two individual materials among fibrous composite materials

positioning the at least two individual material onto the other applied materials

inserting the thus applied individual materials and other materials into a container

evacuating the container, infusing a curing resin, and allowing the resin to cure, and

de-moulding from the mould the shell thus fabricated.