Semi-submersible floats, especially for wind turbines

Abstract

To have concept stipulation progress for a semi-submersible type float for a wind power turbine in conventional technology.SOLUTION: A semi-submersible type float (2), especially for an ocean wind turbine (1), comprises at least four columns including a central column (3) as well as three outside columns coupled to the central column by an arm (7) in a shape of a pontoon, the outside columns and the pontoon arm including a ballast (10). The ballast (10) is filled by gravity and emptied by using compressed air.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a float, in particular for offshore wind turbines. [Background technology]

[0002] For example, the invention may relate to semi-submersible floats, also called hybrid floats, made from steel or concrete, or from steel and concrete. Such hybrid floats are already known in the prior art, for example from patent document WO 2014 / 031009. This document describes such a float comprising at least four columns, including a central column and three outer columns connected to the central column by arms in the form of pontoons. In this document, the outer columns are connected to a central column in a star-shaped configuration.

[0003] The outer column of the float and the arms forming the pontoons also contain ballast, making it possible to adjust the level of buoyancy of the float. This allows the wind turbine to be transported and installed at a power production site. This so-called float of hybrid nature uses a mixed structure, for example made of steel for the columns and, for example, made of concrete for the supports between them forming the pontoons.

[0004] In the aforementioned prior art documents, means are also provided for emptying the ballast by pumping. The means of using the pumps actually make it possible to pump water out of the ballast so as to change the buoyancy of the assembly. This prior art document therefore broadly describes the concept of a semi-submersible float for a wind turbine. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to advance the conceptual definition of this type of float. [Means for solving the problem]

[0006] To this end, the invention relates to a semi-submersible float, in particular for offshore wind turbines, comprising at least four columns including a central column and three outer columns connected to the central column by arms in the form of pontoons, the outer columns and the pontoon arms containing ballast, the ballast being characterised in that the ballast is filled by gravity and emptied using compressed air.

[0007] According to other characteristics of the float according to the invention, the following are taken into account, either alone or in combination: The ballast of the arm includes a portion that extends into the central column. Compressed air for emptying is provided by a compressed air source carried by the support vessel and coupled to a branching means to a connecting means for connecting to the ballast. the compressed air source includes means forming an air compressor; the branching means including a connecting pipe extending into the central column between the portion of the ballast extending into the central column and a connecting means for connecting to a source of compressed air provided at the top of said central column. - The ballast includes a rising section in the outer column. - These columns have a cylindrical cross section. - The pontoon arms have a rectangular cross section. The pontoon arms include partition walls that define compartment boundaries in the corresponding ballast sections. - The columns are made of steel and the arms of concrete and the columns are connected to the arms by fixing flanges which are joined with post-stressing members embedded in the concrete of the pontoon arms.

[0008] The invention will be better understood on reading the following description, given solely by way of example and made with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 shows a perspective view of an exemplary embodiment of a submersible float for an offshore wind turbine according to the present invention. [Diagram 2] FIG. 2 shows a schematic side view showing the ballast of such a float. [Diagram 3] FIG. 3 shows a partial cutaway view of such floats and showing their ballast. [Figure 4] FIG. 4 shows a schematic diagram illustrating such a means for emptying the ballast. [Diagram 5] FIG. 5 shows the connection between the outer column and the pontoon arms of such a float. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] FIG. 1 shows in fact a semi-submersible float, in particular for offshore wind turbines. The offshore wind turbine is designated in this FIG. 1 by the common reference number 1 and the float is designated by the common reference number 2.

[0011] In this application, a hybrid float is described, ie, a float that uses two different materials to construct its components. Thus, and as described in the prior art documents cited above, such a float comprises at least four columns, including a central column designated by the common reference numeral 3 and three outer columns designated by the common reference numerals 4, 5 and 6, constructed, for example, of steel or concrete.

[0012] The outer columns 4, 5 and 6 are connected to the central column 3 by arms in the form of pontoons (or pontoon arms) made of steel or concrete, two of which, e.g. 7 and 8, are shown in this FIG.

[0013] As also indicated above, the central and outer columns can be steel or concrete columns and have a cylindrical cross-section, while the pontoon arms can be made of steel or concrete and have a rectangular cross-section. In this float, the outer column and pontoon arms contain ballast.

[0014] Such a ballast is shown, for example, in FIGS. In fact, the figures show a central column 3, an outer column, for example 4, and a pontoon arm, for example arm 7, connecting the outer column to the central column. As shown, the outer column and pontoon arms include ballast, such as ballast indicated by the reference numeral 10 common to FIGS.

[0015] Near one of their ends, the ballasts extend in the outer column of the float and include a portion that rises into the corresponding outer column 4, for example the ballast portion indicated by the common reference numeral 11 in this FIG. 4, as shown more clearly in FIG. At the other of their ends, the ballasts include, for example, a portion extending in the central column 3 , which is designated in the figures by the common reference number 12 for the ballast 10 .

[0016] Also, as can be seen in these figures, the columns may have a cylindrical cross-section, while the pontoon arms may have a rectangular cross-section. More specifically, and as shown in particular in FIG. 4, this central column 3 of floats also includes connection means for connecting the ballast to a source of compressed air for emptying.

[0017] Thus, in the floats described, the ballast is filled by gravity and emptied by compressed air. In those figures, and in particular in FIG. 4, there are shown connection means, indicated in this figure by the common reference number 13, for connecting the ballast parts extending into the central column, e.g. 12, to a source of compressed air for emptying said ballast. This compressed air source is designated by the common reference numeral 14 in this FIG.

[0018] In practice, this compressed air source may be carried, for example, by a support vessel, indicated by the common reference number 15 in this FIG. 4, and may include means, forming, for example, an air compressor, coupled with branching means, indicated by the common reference number 16, for connecting this compressed air source to means 13 for connecting to ballast.

[0019] In fact, in such floats, their ballast is connected to a compressed air pipe or a path for emptying, and it can be seen that it is possible to connect a compressor to the ballast so as to ensure their emptying. Such quick connection means of a conventional kind are therefore provided, for example at the top of the central column, to enable connection of a compressed air source to the ballast.

[0020] Compressors can also be shared among several wind turbines, for example at a power production site. Support vessels or the like can also be used to move these means between different wind turbines, for example at a facility, to reduce the costs of their installation and operation. In practice, quick connection means of conventional type can be used to connect the compressor carried by the ship to the compressed air path for emptying the ballast. The ballast is also filled by gravity and emptied by compressed air as previously described.

[0021] Also illustrated in FIG. 4 is the fact that the ballasts may, for example, include therein partition walls that define boundaries, which may or may not be sealed, constituting separate compartments of the ballasts. For example, the ballast designated by the common reference number 10 in FIG. 4 includes three intermediate partition walls, respectively 20, 21 and 22, making it possible to define different compartments within the latter.

[0022] In FIG. 5, examples of connection means between the pontoon arms, e.g. 7, and the outer columns, e.g. 4, are shown. This connection can for example be made by means of a flange, indicated by the common reference number 25, to which the steel column 4 is fixed in one way or another, for example by welding or screwing.

[0023] This flange includes a hole, e.g. 26, for the passage of a post-stressing member 27 embedded in the concrete of a pontoon arm, e.g. 7. This also makes it possible to ensure that the flange made of steel is fixed to the pontoon arm and that the column is fixed to this arm, for example by welding. Of course, further aspects may be considered.

Claims

1. 1. An assembly including a semi-submersible float (2) for an offshore wind turbine (1), comprising at least four columns including a central column (3) and three outer columns (4, 5, 6) connected to said central column by arms (7, 8) in the form of pontoons, said outer columns and said arms in the form of pontoons containing ballast (10), said ballast (10) being evacuated by compressed air, The semi-submersible float (2) has connection means (13) for connecting the ballast (10) to a source of compressed air (14); said ballast (10) being a gravity-filled ballast, and said assembly comprising a support vessel (15), a branching means (16) to said connection means (13), and said compressed air source (14) for supplying exhaust compressed air for emptying said ballast (10), said compressed air source (14) being carried by said support vessel (15) and connected to said branching means (16); the ballast (10) of the arm comprises a portion (12) which extends into the central column (3), and the connection means (13) comprises a connecting pipe extending in the central column (3) between the portion (12) of the ballast (10) which extends into the central column and a connection means for connecting to a compressed air source (14), provided at the top of this central column, An assembly including a semi-submersible float (2) for an offshore wind turbine (1).

2. The assembly of claim 1 , wherein said source of compressed air includes means forming an air compressor (14).

3. 3. An assembly according to claim 1 or 2, wherein the ballast (10) comprises a portion (11) rising in the outer column (4, 5, 6).

4. An assembly according to any one of claims 1 to 3, wherein the column has a cylindrical cross-section.

5. An assembly according to any one of claims 1 to 4, wherein the arms in the form of pontoons have a rectangular cross section.

6. An assembly according to any one of the preceding claims, wherein said arms (7, 8) in the form of pontoons comprise, in the corresponding ballast section, partition walls (20, 21, 22) which define the boundaries of the compartments.

7. An assembly according to any one of claims 1 to 6, wherein the column (4) is made of steel and the arm of concrete, and the column is connected to the arm (7) by means of fixing flanges (25) connected with post-stressing members (27) embedded in the concrete of the arm in the form of pontoons.

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