Wind turbine blade having a corrosion protection structure, and wind turbine having the same

Abstract

The present invention relates to a wind turbine component, having a connecting portion for connecting the wind turbine component to another turbine component and at least part of the connecting portion is formed of a first type of metal, characterized in that: the connecting portion is further provided with an additional part formed of a second type of metal which is connected to the metallic part of the connecting portion; and the second type of metal is more active than the first type of metal, whereby the additional part forms a sacrificial anode. The present invention further relates to a wind turbine having the above component.

Claims

1. A wind turbine blade having a connecting portion at a root section for connecting the wind turbine blade to a hub, the root section provided with a plurality of inserts extending into the wind turbine blade spaced around the root section by which the connection can be made between the wind turbine blade and the hub, the plurality of inserts having exposed end faces and being formed of a first type of metal, wherein additional parts of a second type of metal are connected to the plurality of inserts, the second type of metal being more electrochemically active than the first type of metal, whereby the additional parts form a sacrificial anode.

2. The wind turbine blade according to claim 1, wherein the plurality of inserts are of cylindrical form at an end region adjacent their exposed face, and the additional parts are in the form of a ring secured on an outside of the cylindrical form.

3. The wind turbine blade according to claim 1, wherein adhesive is provided between the plurality of inserts and the blade root section to fasten the plurality of inserts therein, and the additional parts are arranged at a boundary, which is facing an exterior environment, of the plurality of inserts and the blade root section; and the boundary between the additional parts and the blade root section is also covered with adhesive so as to prevent water/moisture etc. from contacting with the plurality of inserts through the boundary between the additional parts and the blade root section.

4. The wind turbine blade according to claim 1, wherein the first type of metal is steel or iron, and the second type of metal is zinc, aluminum or magnesium.

5. A wind turbine, having a wind turbine blade according to claim 1.

6. The wind turbine blade according to claim 1, wherein ring-like additional parts are at least partially embedded in the blade root section.

7. A wind turbine blade having a connecting portion at a root section for connecting the wind turbine blade to a hub, the root section provided with a plurality of elongate inserts extending into the blade spaced around the root section by which the connection can be made between the wind turbine blade and the hub, the inserts having end regions with exposed end faces and being formed of a first type of metal, wherein ring-like additional parts of a second type of metal are connected to the inserts to encircle the end regions thereof, and are at least partly embedded in the blade root section, the second type of metal being more electrochemically active than the first type of metal, whereby the additional parts form a sacrificial anode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention and its many advantages will be described in more detail below with reference to the accompanying schematic drawings which, for the purpose of illustration, show some non-limiting embodiments and in which

(2) FIG. 1 schematically illustrates a wind turbine;

(3) FIG. 2 schematically illustrates a side perspective of a connecting portion of a turbine blade;

(4) FIG. 3 exemplarily illustrates a cross-section of an insert arrangement according to one embodiment of the present invention; and

(5) FIG. 4 exemplarily illustrates the interaction principle between a steel insert and a zinc ring when corrosion occurs.

(6) All the drawings are schematic and not necessarily to scale, and they show only those parts necessary to elucidate the invention, other parts being omitted or merely suggested.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

(7) FIG. 1 illustrates a wind turbine 1, comprising a wind turbine tower 2 and a wind turbine nacelle 3 positioned on top of the tower 2. The wind turbine rotor 4 comprises at least one wind turbine blade e.g. three wind turbine blades 5 as illustrated in the figure. The rotor is mounted on a hub 6, which is connected to the nacelle 3 through the low speed shaft extending out of the nacelle front. The wind turbine tower 2 is erected on a foundation 7 either at ground level or at sea level 8 according to whether the wind turbine is of an onshore or an offshore type.

(8) FIG. 2 illustrates a blade root section 11, with inserts 12 circumferentially provided in the root section for connecting the blade with hub. In this example, each insert is made from metal such as steel. However, other metallic materials could be used.

(9) FIG. 3 shows a cross-section of an insert arrangement, wherein each insert 12 is secured in respective hole in the blade root section 11 and a high-strength adhesive 13 is provided therebetween to secure the insert 12 therein. According to one embodiment of the present invention, the inserts 12 are of cylindrical form at end region adjacent their exposed face, and a corrosion protection structure is provided in the form of a metallic ring 14 fitted on the outside of the end of each insert 12 with the material selected so as to provide a cathodic protection. Thus, material of the ring 14 is more electrochemically active than that of insert 12 in order to create cathodic protection. In a preferred form, ring 14 is made of zinc (Zn), however, it should be understood that all other metallic materials having suitable electrical attribute could be used. The ring 14 will act as a sacrificial anode providing corrosion protection to the exposed end face and in particular at the bond line between the insert 12 and the hole in the blade root section 11.

(10) In order to further enhance corrosion protection effect, the ring 14 may be partially covered with adhesive to prevent water/moisture from entering into the bond line between the insert 12 and the hole in the blade root section 11. As a preferred form, as shown in FIG. 3, adhesive 13 is provided between the insert 12 and the blade root section 11 to fasten the insert 12, and the ring 14 is arranged at the boundary, which is facing exterior environment, of the insert 12 and the blade root section 11. The ring 14 could be at least partially embedded into the boundary between the insert 12 and the blade root section 11, as shown in FIG. 3. Then, boundary between the ring 14 and the blade root section 11 is also covered with adhesive so as to prevent water/moisture etc. from contacting the insert 12 through the boundary between the ring 14 and the blade root section 11.

(11) FIG. 4 illustrates the underlying principle of cathodic protection by exemplarily showing the interaction between the steel insert 12 and the sacrificial zinc ring 14. When surface water is present on the exposed end of the insert 12, in the presense of air, the steel insert and the sacrificial anode act as an electrical circuit, the zinc will lose electrons and go into solution as zinc cations. Electrons released from the zinc atoms flow through metallic conduction to the steel where dissolved oxygen is reduced, by gaining the electrons released by the zinc, to hydroxide anions.

(12) Although the use of a zinc anode is preferred, as long as it is more electrically active compared to steel or iron inserts and readily accessible and inexpensive, other metals could be used such as such as aluminum or magnesium.

(13) Also, depending on the specific need of corrosion protection, shape, size, and location etc., of the sacrificial anode can be changed or supplemented with additional parts.

(14) Again, although the above embodiment only describes cathodic protection of connecting portion of a blade root, the present invention is not limited to a blade root connecting portion; rather, it can be applied to other components where same need exists, in particular where a part is exposed to the exterior prior to installation, such as tower connecting portion, the connecting portion between tower and nacelle, and the connecting portion between nacelle and hub etc.

(15) Although the invention has been described above in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims.