ES2363615B2 - SHOVEL FOR AIRBRUSHERS - Google Patents

Abstract

Wind turbine blade that extends from a root (1) where the blade is attached to a rotor, to a tip (2). The blade has fasteners for replaceably mounting the tip (2) at one end (3) of the blade opposite the root. The tip (2) has the following characteristics: length L, 0? 1m <= L <= 0.6m, volume less than 0.03 m {sup, 3}; It is aerodynamic and has a series of geometric tolerances: rope: + -0.3mm; profile thickness: + -0.2mm; output edge thickness: + -0.1mm; torsion: + -0.05º; It has a thickness E and a rope C, E> 14% C; It is of machinable material.

Description

Wind turbine blade.

Field of the Invention

The invention relates to wind turbine blades incorporating an aerodynamic blade tip to reduce aerodynamic noise.

Background of the invention

The aerodynamic noise generated by the wind turbine blades can be classified according to the following criteria:

-

Turbulent boundary layer noise at the trailing edge: it is caused by a fluctuating pressure deficit between the pressure side and the suction side when the flow reaches the trailing edge. The frequency is broadband and is related to boundary layer parameters (typically from 100 Hz to 10,000 Hz, more present at medium frequencies around 1000 Hz).

-

Tip noise: it is caused by turbulence in the tip vortex. The frequency is broadband and is related to the diameter of the tip vortex (typically between 1000 Hz and 8000 Hz).

-

Loss of entry noise: it is caused by pressure fluctuations in the areas of flow separation, often present at high angles of attack. The frequency is broadband and is related to the extent of the input area in loss (typically between 20 Hz and 1000 Hz).

-

Vortex noise of the laminar boundary layer: it is caused by instabilities on the pressure side of the boundary layer causing the formation of vortices. The frequency is tonal and is related to the thickness of the boundary layer on the pressure side (typically between 1000 Hz and 4000 Hz).

-

Blunt exit edge noise: originates from the small fl ow separation zone behind a blunt exit edge that causes vortex formation (well known as von Karman's vortex formation). The frequency is tonal and is related to the thickness of the trailing edge (typically between 1000 Hz and 4000 Hz).

-

Flow noise over holes, cuts, intrusions: it is caused by unstable flows and the formation of vortices. The frequency is tonal and is related to the dimension of the fl ow distorting elements (typically between 1000 Hz and 10,000 Hz).

The blade object of the invention helps to reduce aerodynamic noise produced during the operation of the wind turbine.

ES2161196 shows a windbreaker installation for wind turbines comprising an aluminum cap at the end of each blade, an aluminum profile at the edge of each blade and a conductor parallel to the mast of the blade so that the profile and the conductor derive so parallel lightning.

WO2005031158 shows a wind turbine blade comprising lightning protection means. At least one section of the blade tip is made of metal and is part of the protection means.

Description of the invention

One aspect of the invention relates to a wind turbine blade that extends from a root where the blade is attached to a rotor, to a tip. The blade tip of the invention makes it possible to achieve geometric tolerances in this critical zone of the blade that cannot be achieved by the usual blade designs; Normally, the blades are made of carbon fiber, and the blade tip of the invention makes it possible to achieve thicknesses that cannot be given with carbon fiber. This dimensional control means that the noise dispersion generated at the blade tip, which is ± 1 dB in conventional blades, can be reduced to ± 0.5 dB in the blades of the invention. The shovel:

comprises fixing means for replaceably mounting the tip at one end of the blade opposite the root;

tip:

has a length L, 0’1 m ≤ L ≤0’6 m;

It has a sufficient volume to achieve the required tolerances to solve noise problems, typically the volume is less than 0.03 m3;

It is aerodynamic and has a plurality of geometric tolerances between: rope: ± 0.3 mm; profile thickness: ± 0.2 mm; output edge thickness: ± 0.1 mm; torsion: ± 0.05º;

It has a thickness E and a rope C, E> 14% C; It is of machinable material. The values in the tolerances that are achieved in conventional blades versus those allowed by the present invention are reflected below:

The fixing means may comprise first fixing elements and second fixing elements selected from: a plurality of threaded holes and screws; a plurality of overlap tabs; a plurality of crimping edges; and combinations thereof; the first fixing elements being located in a component selected between, the tip and the end, and the second fixing elements in the conjugate component to constitute the fixing between both components. The blade can also comprise: a trailing edge of the blade of metallic material from the root to the tip.

In the blade of the invention, at least one element selected between the tip and the trailing edge, can also comprise drainage means constituted by at least one through hole from an inner cavity to an outer surface, the outer surface being continuous.

Additionally, in the blade of the invention, at least one element selected between the tip and the trailing edge may further comprise beaconing means constituted by a housing provided with a light source covered by a housing flush with the outer surface.

On the other hand, at least one element selected between the tip and the trailing edge may be of a material added with conductive particles configured to derive a lightning discharge to a ray transmission system included in the blade, the tip having together with the trailing edge weighing less than 90 kg.

The trailing edge may comprise a plurality of sections joined one after the other, configured to be disassembled independently and to ensure an electrical conductivity from the tip to the root.

Brief description of the drawings

A series of drawings that help to better understand the invention and that expressly relate to an embodiment of said invention that is presented as a non-limiting example thereof is described very briefly below.

Figure 1 is a side view of a wind turbine showing the blade of the invention. Figures 2A, 2B, 2C show different means of fixing the tip to the end. Figure 3 shows a blade tip and a trailing edge.

Description of a preferred embodiment of the invention

An embodiment of the invention refers to a wind turbine blade that extends from a root (1) where

The blade is attached to a rotor, up to a tip (2). The blade: comprises fixing means for replaceably mounting the tip (2) at one end (3) of the blade opposite the root;

the tip (2): has a length L, 0’1 m ≤ L ≤0’6 m; It has a volume of less than 0.03 m3; It is aerodynamic and has a plurality of geometric tolerances between:

rope: ± 0.3 mm; profile thickness: ± 0.2 mm; output edge thickness: ± 0.1 mm; torsion: ± 0.05º;

It has a thickness E and a rope C, E> 14% C; It is of machinable material. The fixing means comprise first fixing elements (100, 101, 102) and second fixing elements.

fixation (200, 201, 202) selected from: a plurality of threaded holes (100) and screws (200); a plurality of overlap tabs (101, 201); a plurality of crimping edges (102, 202); and combinations thereof;

the first fixing elements (100, 101, 102) being located in a component selected between the tip

(2) and the end (3), and the second fixing elements (200, 201, 202) in the conjugate component (3, 2) to constitute the fixing between both components.

The blade also includes:

an exit edge (4) of the metal material blade from the root (1) to the tip (2).

In one embodiment of the invention, at least one element selected between the tip (2) and the trailing edge (4), also comprises drainage means constituted by at least one through hole (22, 32) from an inner cavity (20 , 30) to an outer surface (21, 31), the outer surface (21, 31) being continuous.

Additionally, in another embodiment of the invention, at least one element selected between the tip (2) and the trailing edge (4) further comprises beaconing means constituted by a housing (23, 33) provided with a light source (24, 34) covered by a housing (25, 35) flush with the outer surface (21, 31).

In another embodiment of the invention, at least one element selected between the tip (2) and the trailing edge (4) is of a material added with conductive particles configured to derive a lightning discharge to an included lightning transmission system. on the blade, the tip (2) together with the trailing edge (4) weighing less than 90 kg.

The trailing edge (4) comprises a plurality of sections joined one after the other, configured to be disassembled independently and to ensure an electrical conductivity from the tip (2) to the root (1).

Claims (8)

1. A wind turbine blade that extends from a root (1) where the blade is attached to a rotor, up to a tip (2), characterized in that: it comprises fixing means for replaceably mounting the tip (2) at one end (3) of the blade opposite the root; the tip (2): has a length L, 0’1 m ≤ L ≤0’6 m; It has a volume of less than 0.03 m3; It is aerodynamic and has a plurality of geometric tolerances between: rope: ± 0.3 mm; profile thickness: ± 0.2 mm; output edge thickness: ± 0.1 mm; torsion: ± 0.05º; It has a thickness E and a rope C, E> 14% C; It is of machinable material. 2. The blade of claim 1 characterized in that the fixing means comprise first fixing elements (100, 101, 102) and second fixing elements (200, 201, 202) selected from: a plurality of threaded holes (100) and screws (200); a plurality of overlap tabs (101, 201); a plurality of crimping edges (102, 202); and combinations thereof, the first fixing elements (100, 101, 102) being located in a component selected between the tip

(2)

and the end (3), and the second fixing elements (200, 201, 202) in the conjugate component (3, 2) to constitute the fixing between both components.

3. The blade of any one of claims 1-2 characterized in that it further comprises an exit edge

(4)

of the metal material blade from the root (1) to the tip (2).

Four.

The blade of any one of claim 3 characterized in that at least one element selected between the tip (2) and the trailing edge (4), further comprises drainage means constituted by at least one through hole (22, 32) from a cavity inner (20, 30) to an outer surface (21, 31), the outer surface (21, 31) being continuous.

5.

The blade of any one of claims 3-4 characterized in that at least one element selected between the tip (2) and the trailing edge (4) further comprises beaconing means constituted by a housing (23, 33) provided with a light source (24, 34) covered by a housing (25, 35) flush with the outer surface (21, 31).

6.

The blade of any one of claims 3-5 characterized in that at least one element selected between the tip (2) and the trailing edge (4) is of a material added with conductive particles configured to derive a lightning strike to a system lightning transmission included in the blade, the tip (2) together with the trailing edge weighing less than 90 kg.

7.

The blade of claim 6-7 characterized in that the trailing edge (4) comprises a plurality of sections joined one after the other, configured to be disassembled independently and to ensure an electrical conductivity from the tip (2) to the root (1).

SPANISH OFFICE OF THE PATENTS AND BRAND Application no .: 200800580 SPAIN Date of submission of the application: 28.02.2008 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE 51 Int. Cl.: F03D1 / 06 (2006.01) RELEVANT DOCUMENTS

Category

Documents cited Claims Affected

TO

US 5320494 A (REINFELDER WILLIAM C ET AL.) 06/14/1994, Entire document one

TO

US 2006104812 A1 (KOVALSKY DAVID A ET AL.) 05/18/2006, Entire document. one

TO

US 2001023907 A1 (TSUKAHARA TAKANORI ET AL.) 09/27/2001, Summary. Figures. one

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the date of priority submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims • for claims no:

Date of realization of the report 22.07.2011

Examiner M. López Carretero Page 1/4

REPORT OF THE STATE OF THE TECHNIQUE Application number: 200800580 Minimum documentation sought (classification system followed by classification symbols) F03D, B64C Electronic databases consulted during the search (name of the database and, if possible, terms of search used) INVENES, EPODOC State of the Art Report Page 2/4  WRITTEN OPINION Application number: 200800580 Date of Completion of Written Opinion: 07.27.2011 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims Claims 1-7 IF NOT

Inventive activity (Art. 8.1 LP11 / 1986)

Claims Claims 1-7 IF NOT

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/4  WRITTEN OPINION Application number: 200800580 1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

US 5320494 A (REINFELDER WILLIAM C et al.) 14.06.1994

D02

US 2006104812 A1 (KOVALSKY DAVID A et al.) 05/18/2006

D03

US 2001023907 A1 (TSUKAHARA TAKANORI et al.) 27.09.2001

2. Statement motivated according to articles 29.6 and 29.7 of the Regulations for the execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement The present patent application in its independent claim 1 claims a wind turbine blade that extends from a root, where the blade is attached to the rotor, to a tip, characterized in that it comprises means for replacing the tip at a replaceable end. the blade opposite the root, and also the tip is aerodynamic and: -It has a length L, 0 1m <= L <= 0 6m -Volume less than 0.03m3 -Ceda: + -0.3mm -Profile thickness: + -0.2mm -Top edge thickness + - 0.1mm -Torsion: + -0.05º -It has a thickness E and a rope C, E> 14% C -It is machinable material The documents cited D01, D02 show helicopter rotor blades with replaceable tips and with different means of fixing to this, that although without its objective the reduction of the noise does not present the specific characteristics and geometric tolerances claimed in the application. Document D03 shows another way to reduce aerodynamic noise with a tip configuration. These documents show the general state of the art and are not considered of particular relevance. Therefore it can be considered that the invention is new and implies inventive activity as required by the Arts. 6.1 and 8.1 of Patent Law 11/86. State of the Art Report Page 4/4