Mass produced composite wind turbine blades

• US 20100226775A1
• Filed: 04/08/2010
• Published: 09/09/2010
• Est. Priority Date: 03/06/2009
• Status: Active Grant

• Current Assignee: Sustainable Structures LLC
• Original Assignee: Paul Harvey Hartman
• Inventors: Hartman, Paul Harvey
• Granted Patent: US 8,348,618 B2
• Time in Patent Office: Days
• US Class Current: 416/131
• CPC Class Codes: B60L 53/30 Constructional details of charging stations
• CPC Class Codes: B60L 53/31 Charging columns specially adapted for electric vehicles
• CPC Class Codes: B60L 53/51 Photovoltaic means
• CPC Class Codes: B60L 53/53 Batteries
• CPC Class Codes: B60L 53/60 Monitoring or controlling charging stations
• CPC Class Codes: B60L 53/80 Exchanging energy storage elements, e.g. removable batteries
• CPC Class Codes: E04H 6/025 in the form of an overhead canopy, e.g. carports
• CPC Class Codes: F03D 9/25 the apparatus being an electrical generator F03D9/22 takes precedence
• CPC Class Codes: G06Q 20/10 specially adapted for electronic funds transfer [EFT] systems; specially adapted for home banking systems
• 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
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

A renewable energy system for directly charging electric and hybrid vehicles is shown for areas with moderate wind and/or solar resources. The wind turbine blades and rotor assemblies for capturing the wind resources show significant improvements in both cost of manufacture and site assembly compared to three-bladed horizontal axis turbines. A simple, easily manufactured blade pivoting mechanism is shown to improve the performance of vertical axis turbines. A related improvement for varying blade pitch along the axis of horizontal axis turbine blades allows for production using continuous mass-production methods rather than the labor and cost intensive current practice of molding the blades. The blade assemblies are completely scalable and can be easily customized for particular applications/sites.

Claims

1. A wind turbine blade construction comprising an assembly of an airfoil profile and an unsymmetrical I beam,

said airfoil profile elongated in a first direction and having

perpendicular to said first direction;

a single interior surface with engagement means for receiving and aligning said unsymmetrical I beam, an exterior surface corresponding to an aerodynamic shape with a leading edge and a trailing edge, said leading edge and said trailing edge connected by a chord line,

said unsymmetrical I beam having a web section integral to two flanges, a first flange proximal to said leading edge and a second flange proximal to said trailing edge, with both said flanges bonded to said single interior surface at said engagement means in the completed turbine blade construction, with

said web section having a medial plane roughly perpendicular to each of said two flanges and said medial plane forming a designed angle with said chord line in a plane perpendicular to said first direction,

whereby;

said beam can be easily modified and the airfoil profile customized to optimize performance in a particular application and said assembly can be produced using low cost, constant profile, mass production methods.

2. The wind turbine blade construction of claim 1, wherein said first flange forms a shallow draft angle with said second flange when viewed from the perspective of said trailing edge with each of said two flanges having roughly constant widths along said first direction,

with said airfoil profile having means for twisting deformation during assembly of the blade construction and with said designed angle varying linearly along said first direction,

whereby: a low cost, uniform section blade construction can be produced with a twist along its length for use in horizontal axis turbines and the unsymmetrical I beam can be utilized to make a simple, strong structural connection to a horizontal turbine rotor hub.

3. The wind turbine blade construction of claim 1, wherein said unsymmetrical I beam extends beyond at least one end of said airfoil profile, forming at least one end portion of said unsymmetrical I beam, and

each said end portion has a proximal portion near said airfoil profile and a distal portion having hub connection means for assembling said blade construction into a turbine rotor, said unsymmetrical I beam also including a flattened portion of a predetermined length between said proximal and distal portions,

with said two flanges substantially removed from said unsymmetrical beam at said flattened portion and said flattened portion having a thickness and a width roughly equal to that of said web section,

with said flattened portion having a material property of torsional modulus, a material property of elastic limit, and a physical configuration made up of;

said thickness, said width, and said predetermined length, such that said flattened portion comprises an integral blade pivoting means for responding to aerodynamic and physical forces on said blade construction under normal wind conditions and for bearing increased forces on said blade construction under extreme wind conditions without exceeding said elastic limit,

whereby;

said wind turbine blade construction can function to vary pitch around the rotational circuit of a wind turbine to enhance performance without the use of complex systems of mechanical pivots and cams.

5. The wind turbine blade construction of claim 1, wherein said interior surface engagement means comprise two thickened areas of said airfoil profile at said interior surface, one on each side of said chord line,

each of said thickened areas having a linear extent of slightly less than the width of said web section when projected onto said medial plane,

whereby:

said airfoil profile can be precisely aligned and bonded to said unsymmetrical I beam at the junctions of said thickened wall areas and said flange portions.

6. The wind turbine blade construction of claim 1, wherein said unsymmetrical I beam is bonded to said airfoil portion using an adhesive.

7. The wind turbine blade construction of claim 1, wherein said unsymmetrical I beam is composed of a fibrous reinforcement within a matrix of resin material, with

said fibrous reinforcement selected from the group consisting of;

fiberglass unidirectional rovings and stitched triaxial fiberglass fabric and non-woven glass fabric and 0/90 glass fabrics, and

said resin material selected from the group consisting of;

epoxy polymers and urethane polymers and phenolic polymers and polyester polymers and vinyl based polymers,

whereby;

the beam can be produced using continuous production pultrusion methods.

8. The wind turbine blade construction of claim 2, wherein said means for twisting deformation comprise;

said airfoil profile having a constant cross section and having a material composition selected from the group consisting of;

thermoset fiber reinforced composites having post cure characteristics and aluminum and thermoplastic polymers and filled thermoplastic materials and thermo formable laminated composite materials,

whereby;

overall cost can be reduced by relying on said unsymmetrical beam for desired structural and mechanical properties.

11. The wind turbine blade construction of claim 3, wherein said hub connection means include,

through holes at said distal portion and

receiving means for engaging threaded fasteners, said threaded fasteners passing through said through holes and entering said receiving means during assembly of said turbine rotor,

whereby:

a number of said blade constructions can be shipped to a site in compact, flat form and easily be assembled into a much larger rotor using minimal lifting equipment and ordinary hand tools.

12. The wind turbine blade construction of claim 3, wherein said hub connection means include said thickness and said width of said flattened portion and

said turbine rotor includes a rectangular slot, said slot having a slightly larger width and a slightly larger depth than said flattened portion, with

said hub connection means, said rectangular slot and a locking means for constraining said flattened portion within said slot comprising a hub assembly system,

whereby:

torque applied by the blade construction to the assembly system during operation of the wind turbine cannot affect attachments to the rotor.

15. The wind turbine blade construction of claim 1, wherein said assembly of said airfoil profile and said unsymmetrical I beam exists only near the ends of said airfoil profile.

16. The wind turbine blade construction of claim 15, wherein a light weight wood part is bonded to at least part of said interior surface with an adhesive at a center section of said airfoil profile,

whereby:

acceptable load transfer properties can be obtained at said center section without incurring high costs.

17. The wind turbine blade construction of claim 15, wherein a foam material fills said airfoil profile and bonds to said interior surface at a center section of said airfoil profile,

whereby:

acceptable load transfer properties can be obtained at said center section without incurring high costs.

4. A wind turbine blade comprising an assembly of an airfoil portion and at least one composite strip,

said airfoil portion elongated in a first direction and having

perpendicular to said first direction;

an exterior surface corresponding to an aerodynamic shape with a leading edge and a trailing edge, said leading edge and said trailing edge connected by a chord line,

the airfoil portion having engagement means for securing said at least one composite strip at each end, with

said at least one composite strip having locking means for securing to said airfoil portion at a first location, rotor attachment means for securing to a wind turbine rotor assembly at a second location and an unmodified section having a design length between said two locations, with a roughly constant width and a roughly constant thickness throughout said unmodified section, with

said unmodified section having a material property of torsional modulus, a material property of elastic limit, and a physical configuration made up of;

said constant thickness, said constant width, and said design length, such that said unmodified section comprises a blade pivoting means for responding to aerodynamic and physical forces on the blade under normal wind conditions and for bearing increased forces on the blade under extreme wind conditions without exceeding said elastic limit,

whereby;

said wind turbine blade can function to vary pitch around the rotational circuit of a wind turbine to enhance performance and can be mass produced from low cost materials with very low tooling and fabrication costs.

9. The wind turbine blade of claim 4, wherein said composite strip engagement means include said airfoil portion having a material composition with capabilities for crimping deformation, said material composition selected from the group consisting of;

aluminum and thermoset fiber reinforced composites having post cure characteristics and thermoplastic polymers and filled thermoplastic materials and thermo formable laminated composite materials,

whereby;

said engagement means can be actuated through the application of heat or force or a combination of the two to said airfoil profile.

10. The wind turbine blade of claim 4, wherein said composite strip is composed of a fibrous reinforcement within a matrix of resin material, where

said fibrous reinforcement is selected from the group consisting of;

fiberglass unidirectional rovings and stitched fiberglass fabrics and woven glass fabric and nonwoven glass fabric and cellulose and other fibers derived from natural products and carbon fibers and carbon fabrics and aramid fabric and aramid fiber and rock wool and fibers produced from lava, and

said resin material is selected from a group consisting of;

B stage thermoset polymers and pultrusion grade thermoset polymers and engineering grade thermoplastic polymers.

13. The wind turbine blade of claim 4, wherein said rotor attachment means comprise an over molded nib at one end of said at least one composite strip,

said over molded nib having two raised Portions separated by a curved depression perpendicular to said first direction, and

said wind turbine rotor including at least two mounting holes in an area of overlap with said second location, with

said rotor assembly, said at least two mounting holes and u bolt means for engaging said over molded nib and said mounting holes comprising a rotor attachment system,

whereby:

a number of said blades can be shipped to a site in compact, flat form and easily be assembled into a much larger rotor using ordinary lifting equipment and hand tools.

14. The wind turbine blade of claim 4, wherein said locking means comprise an optional over molded composite section,

the over molded section being roughly congruent to said exterior surface at one side and tapered to level with said composite strip at the other side, and

said airfoil profile engagement means comprising a crimped section of said profile in the area of said over molded composite section and extending further towards the end of said airfoil profile to include a portion of said crimped section that is roughly congruent to said composite strip, with

said locking means, said airfoil engagement means and an adhesive layer between the two comprising a blade locking system,

whereby:

the blade is prevented from pulling away from said wind turbine rotor assembly and the length of the blade and subsequent assembly and balancing of the wind turbine rotor can be precisely controlled though fixtures used in the crimping and bonding process.

18. A strut assembly comprising a tubular profile and a composite I beam,

said tubular profile elongated in a first direction and having a single interior surface with engagement means for said composite I beam perpendicular to said first direction,

said composite I beam having a web portion integral with two flanges, and

said web portion having a medial plane perpendicular to each of said two flanges with at least said web portion extending beyond the length of said tubular profile at both ends,

whereby:

structural components can easily be used with other blade and rotor components to create a low cost wind turbine structure with minimal tooling expenditures.

19. The strut assembly of claim 18, wherein said composite I beam is composed of a fibrous reinforcement within a matrix of resin material, where

said fibrous reinforcement is selected from a group consisting of;

fiberglass unidirectional rovings and stitched triaxial fiberglass fabric and non-woven glass fabric and 0/90 glass fabrics, and

said resin material is selected from a group consisting of;

epoxy polymers and urethane polymers and phenolic polymers and polyester polymers and vinyl based polymers.

20. The strut assembly of claim 18, wherein at least one end of said composite beam has engagement means for securing said strut assembly to a wind turbine mast.