A HELICAL STRAKE SET TO REDUCE VORTEX INDUCE VIBRATIONS OF AN EOLIC TOWER

Abstract

Provided is a helical strake set to reduce vortex induced vibrations of a tower, intended to be transported unassembled in a container, including a plurality of identical attachable segments, wherein each segment includes a main body of hollow pyramidal configuration including a wide polygonal end a narrow polygonal end and a narrow polygonal portion firmly attached to the narrow polygonal end, and each segment further including a cap including a wide polygonal portion able to fit in the wide polygonal end by a fastening element, wherein all main bodies and caps are able to be piled in one into another in a container yielding a significant reduction in seaborn transport volume and later assembled on site to reduce vortex induced vibrations of a tower.

Claims

1. A helical strake set to reduce vortex induced vibrations of a tower, intended to be transported unassembled in a container, having a plurality of identical attachable segments, wherein each segment comprises: a main body of hollow pyramidal configuration comprising a wide polygonal end, a narrow polygonal end and a narrow polygonal portion able to rigidly attach to the narrow polygonal end and the narrow polygonal portion further comprises a first through hole, and a cap comprising a wide polygonal portion able to fit in the wide polygonal end and further comprising a second though hole, wherein all main bodies and caps can be securely attached by at least one fastening element and are geometrically configured to be piled in one into the other in the container.

2. The helical strakes according to claim 1, wherein the wide polygonal end comprises two perimetral cavities and the wide polygonal portion comprises two perimetral ribs, wherein the perimetral ribs are able to fit in the perimetral cavities.

3. The helical strakes according to claim 1, wherein the narrow polygonal portion comprises a first hollow knob protruding from the first through hole.

4. The helical strakes set according to claim 1, wherein the cap comprises a second hollow knob protruding from the second through hole.

5. The helical strakes set according to claim 1, wherein the wide polygonal aperture and the narrow polygonal end have a triangular shape.

6. The helical strakes according to claim 6, wherein piled main bodies and caps with triangular shape can be compactly arranged in pillars forming parallelepiped shapes in the container.

7. The helical strakes according to claim 1 wherein each segment is made of plastic manufactured from a blow molding process.

8. The helical strakes according to claim 1, wherein a full helical strake set is assembled in 3-5 m.sup.3 containers.

Description

BRIEF DESCRIPTION

[0029] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0030] FIG. 1 shows a conventional art representation of the way of transport of conventional polystyrene foam helical strakes;

[0031] FIG. 2 shows a perspective view of an unattached segment of the helical strakes set according to an embodiment of the invention;

[0032] FIG. 3 shows an attached segment of the helical strakes set according to an embodiment of the invention;

[0033] FIG. 4 shows a lateral view of the main body securely attached to the cap and two segments fastened together by means of an internal rope according to an embodiment of the invention;

[0034] FIG. 5 shows a perspective view of an embodiment of a helical strakes set being transported in three containers;

[0035] FIG. 6a. shows a schematic view of the helical strake assembled in destination; and

[0036] FIG. 6b shows the helical strake set arrange in streamline around the cross section of the tower outer surface to reduce vortex induce vibrations.

DETAILED DESCRIPTION

[0037] A detailed explanation of an example of an embodiment of the present invention is provided below, with the aid of the aforementioned figures.

[0038] FIG. 1 illustrates a container packed with helical strakes made of polystyrene foam representing a conventional art helical strake set way of transport. It can be clearly seen a significant volume is needed to transport these helical strakes set, requiring containers of an approximate volume of 10 m.sup.3.

[0039] FIG. 2 illustrates a perspective view of an unattached segment (1) of a helical strake set (10) according to an embodiment of the invention.

[0040] It is clearly shown that each segment (1) comprises a main body (2) of hollow pyramidal configuration with a wide polygonal end (21) and a narrow polygonal end (22).

[0041] In an embodiment, the main body (2) further comprises a narrow polygonal portion (24) fitted in the narrow polygonal end (22) forming one rigid piece said main body (2) and comprising a first through hole (26). In an alternative embodiment, said polygonal portion (24) can be removable and attachable to the narrow polygonal end (22) by fastening elements.

[0042] FIG. 2 also illustrates that each segment (1) further comprises a cap (3), wherein said cap (3) comprises a wide polygonal portion (31) able to fit in the wide polygonal end (21) and further comprising a second though hole (33) from where a second hollow knob (32) protrudes thereof.

[0043] As a consequence, with this configuration all main bodies (2) and caps (3) are able to be piled in one into another in respectively in a container (5), yielding a significant volume reduction advantage for seaborn and onshore containers. Additionally, all main bodies (2) and caps (3) are able to be securely attached by at least one fastening and a whole helical strake set (10) to reduce vortex induced vibrations of a tower can be assembled together by means of a rope inserted through the first and second through holes (26,33) and mounted around said tower (11).

[0044] In an embodiment the wide polygonal end (21) and the narrow polygonal end (22) have a triangular shape as is shown in FIG. 2

[0045] FIG. 3 illustrates an attached segment (1) where is it is shown the cap (3) properly attached to the main body (2) forming one attached segment (1) of a plurality of identical attachable segments (1) that stablish a set of helical strakes set (10) able to be used once mounted, to reduce vortex induced vibrations of a tower (11), specially wind turbine's towers experiencing vortex amplification accelerations and resonance.

[0046] FIG. 4 shows a lateral view of the main body (2) securely attached to the cap (3) and two segments (1) fastened together by means of an internal rope (R) according to an embodiment of the invention. More in particular, it shows that in an embodiment the wide polygonal end (21) of the main body (2) comprises two wide perimetral cavities (23) and the wide polygonal portion (31) of the cap (3) comprises perimetral ribs (34), wherein the perimetral ribs (34) can fit in the perimetral cavities (23) defining a first fasten element for securely and firmly attaching a cap (2) to the wide end (21) of the main body (2).

[0047] FIG. 5 illustrates a perspective view of an embodiment of a helical strakes set being transported in containers (5). Accordingly, with the technical features described, main bodies (2) and caps (3) can be vertically piled in into one another in the containers (5) for transport. More in particular, are compactly arranged in pillars forming parallelepiped shapes in the rectangular or squared container (5).

[0048] In the embodiment described in FIG. 5, three containers of 1.2×0.8 m are able to transport a whole helical strakes standard set yielding a total volume of approximately 3-5 m.sup.3. Note, that the equivalent set of helical strakes in the conventional art illustrated in FIG. 1, containers of 10 m.sup.3 are required.

[0049] As a consequence, once the helical strakes set (10) arrive to the required wind turbine destination, all segments (1) can be mounted together forming a helical strake set (10) as shown in FIG. 6a and streamline the cross-section of the tower (11) on its outer surface, as it is illustrated in FIG. 6b.

[0050] In an embodiment, each segment (1) is of plastic manufactured by blow molding. This can greatly reduce costs, achieve required geometries for transport savings, and increase the durability of the helical strakes set (10) in comparison to polystyrene foam.

[0051] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0052] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.