Structure for transport and offshore installation of at least one wind turbine or underwater generator, and methods for transport and offshore installation of at least one wind turbine or underwater generator

A structure for transport and offshore installation of at least one wind turbine or underwater generator includes a U-shaped floating hull having lateral arms. Each lateral arm has at least one leg vertically movable by the hull in flotation, and at least one assembly for supporting a wind turbine or underwater generator. The assembly includes two shuttles opposite each other and each combined with a leg and each having higher and lower pairs of arms which are pivotably movable between a retracted position and an active position tilted against a mast of the wind turbine or underwater generator.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a 35 U.S.C. §371 National Phase conversion of PCT/FR2009/051175, filed Jun. 19, 2009, which claims benefit of French Application No. 0854097, filed Jun. 20, 2008, the disclosure of which is incorporated herein by reference. The PCT International Application was published in the French language.

BACKGROUND OF THE INVENTION

The present invention relates to a structure for transport and offshore installation of at least one wind turbine or underwater generator.

The invention also relates to methods for transport and offshore installation of at least one wind turbine or underwater generator using such a structure.

Traditionally, wind turbines or underwater generators include a mast having a nacelle containing an electrical production means driven by blades.

The mast is mounted on a base secured on the ground or on a sea bottom for an offshore installation.

In the case of wind turbines, the nacelle is fastened to the upper end of the mast and the blades are driven in rotation by the wind.

In the case of underwater generators, the nacelle supported by the mast is placed below the surface of the water and the blades are driven in rotation by the ebb and flow of the water.

The offshore installation of wind turbines or underwater generators consists of placing and fixing the base on the sea bottom, then bringing, most often by transport vessel, the other part of the wind turbines or underwater generators, i.e. the mast bearing the nacelle and the blades.

The mast bearing the nacelle and the blades is placed on the base using different methods.

One known method consists of transporting the mast in a vertical position and suspending said mast from a hoisting apparatus, e.g. a crane supported by a vessel, then gradually lowering the mast using the crane to engage its lower end in the base.

Another known method consists of transporting the mast equipped with its nacelle and its blades in the horizontal position on a vessel, then tilting the mast into a vertical position and gradually lowering the mast using a guide column in order to engage its lower end in the base.

But these known methods have a significant drawback.

Indeed, during the gradual lowering of the mast, the mast is borne by a vessel that is subject to the motion of the swell, with the result that the mast oscillates, which requires that its lower end be held to engage it in the base.

Once its lower end is engaged in the base, the mast still undergoes the motions of the vessel, which can cause significant stresses or strains in the base and buckling of the mast as long as the mast is connected to the vessel.

SUMMARY OF THE INVENTION

The invention aims to propose a structure for transport and offshore installation of at least one wind turbine or underwater generator that avoids this drawback.

The invention therefore relates to a structure for transport and offshore installation of at least one wind turbine or underwater generator comprising a nacelle and blades borne by a mast intended to be mounted on a base anchored on the sea bottom, the structure including:a U-shaped floating hull provided with two parallel lateral arms, each having at least one leg vertically movable relative to the hull in flotation using movement mechanisms, andat least one assembly for supporting the at least one wind turbine or underwater generator, made up of two shuttles opposite each other and each combined with a leg and each having two pairs of arms that are higher and lower, respectively, and pivotably movable around a horizontal axis between a retracted position and an active position tilted against the mast of the wind turbine or underwater generator, the arms of the pair of higher arms including a means for offsetting horizontal movements of the hull relative to the mast after the mast is introduced into the base and after the tilting of the pair of lower arms to the retracted position.

According to other features of the invention:the structure includes two symmetrical assemblies each supporting a mast of a wind turbine or underwater generator,each shuttle includes a means for locking on the corresponding leg,each arm of the pair of higher arms has a length substantially equal to the height of the mast,each arm of the pair of lower arms has a length substantially equal to half the distance separating the inner edges of the two lateral arms of the hull,the free ends of the arms of the pair of lower arms together include an assembly for gripping the mast,the offsetting means mounted at the free ends of the arms of the pair of higher arms include an assembly for supporting the mast via a collar formed on the mast and a sliding means for the horizontal movements of the hull relative to the mast after the introduction of the mast in the base and the tilting of the pair of lower arms to the retracted position,the sliding means of the support assembly comprises, a plate provided with a U-shaped housing, fastened to the free end of one of the arms of the pair of higher arms and intended to cooperate with a locking system mounted at the free end of the other arm of the pair of higher arms and, a platen provided with a U-shaped housing and movable via rolling members on the plate along a plane parallel to the assembly for supporting the mast,the directions of movement of the platen on the plate form a 120° angle between them,the platen includes a latch for closing the U-shaped housing,the U-shaped housings, of the plate and the platen, respectively, are oriented perpendicularly to the longitudinal axis of the hull,the U-shaped housings, of the plate and the platen, respectively, are oriented in the longitudinal axis of the hull towards the open portion of the hull.

The invention also relates to a method for transport an d offshore installation of at least one wind turbine or underwater generator using a structure as previously defined, the method including the following steps:positioning the structure near a loading zone of the wind turbine or underwater generator;placing the legs in the high position and the shuttles in the low position bearing against the hull with the arms of the two pairs of arms in the retracted position,lifting the wind turbine or underwater generator and placing the mast of the wind turbine or underwater generator between the two lateral arms of the hull,tilting the arm including the U-shaped housings of the pair of higher arms to the active position to place the mast in the U-shaped housings below the collar,tilting the other arm of the pair of higher arms to the active position and locking the arms relative to each other,closing the U-shaped housing of the platen using the latch,lowering the mast to make the collar bear on the platen,simultaneously tilting the arms of the pair of lower arms to the active position to hold the lower portion of the mast,locking the platen to the arms,moving the structure bearing the at least one wind turbine or underwater generator to an installation site on a base previously installed on the sea bottom,lowering the legs and locking each shuttle on the corresponding leg,raising the legs to lift the mast using the shuttles and pairs of arms,moving the structure to position the mast in alignment with the base,unlocking the platen from the arms,tilting the arms of the pair of lower arms to the retracted position, the horizontal movements of the hull being offset by the offsetting means of the pair of higher arms,lowering, the legs, the shuttles and the pairs of higher arms to place the mast in the base,opening the U-shaped housing of the platen,unlocking the arms of the pair of higher arms,tilting the arms of the pair of higher arms to the retracted position, andremoving the structure.

The invention also relates to a method for transport and offshore installation of at least one wind turbine or underwater generator using a structure as previously defined, the method including the following steps:opening the door of the structure,placing the legs in an intermediate position and the shuttles in a low position bearing against the hull,placing the arms of the pair of higher arms in the active position and locking them relative to each other with the U-shaped housing of the open platen,moving the structure to place a pontoon including at least one wind turbine or underwater generator between the lateral arms of the hull,engaging the mast in the U-shaped housings of the plate and the platen,closing the housing of the platen using the latch,simultaneously tilting the arms of the pair of lower arms to hold the lower portion of the mast,locking each shuttle on the corresponding leg,raising the legs to lift the shuttles and the pairs of arms to bring the platen in contact with the collar of the mast,raising the mast from the pontoon via shuttles and pairs of arms by lifting the legs,removing the structure bearing at least one wind turbine to place it away from the pontoon,relowering the legs to replace the shuttles in the lower position bearing against the hull,unlocking each shuttle on the corresponding leg,lifting the legs to the higher position,closing the door of the structure,moving the structure bearing the at least one wind turbine or underwater generator to an installation site on a base previously installed on the sea bottom,lowering the legs to a low or intermediate position,locking each shuttle on the corresponding leg,raising the legs to lift the mast using shuttles and pairs of arms,moving the structure to position the mast in alignment with the base,tilting the arms of the pair of lower arms to the retracted position, the horizontal movements of the hull being offset by the offsetting means of the pair of higher arms,lowering the legs, the shuttles and the pair of higher arms to place the mast in the base,opening the U-shaped housing of the platen,unlocking the arms of the pair of higher arms,tilting the arms of the pair of higher arms to the retracted position, andremoving the structure.

DESCRIPTION OF PREFERRED EMOBODIMENTS

FIGS. 1 to 3diagrammatically illustrate a structure10intended for the transport and installation of at least one wind turbine and preferably two wind turbines.

This structure10can also be used for the transport and installation of at least one underwater generator and preferably two underwater generators.

In the following, we will describe the transport and installation of a wind turbine, the transport and installation of another wind turbine being identical.

Generally, the structure10comprises a U-shaped floating hull11including two parallel lateral arms11aopposite each other, connected to each other by a central arm11b.

The lateral arms11aare formed by two floats extending parallel to each other and forming a free space between them and the central arm11bis formed by a cross beam11cborne by said lateral branches11a.

Preferably, the cross beam11cforming the central arm is made up of a mesh of tubes connected to each other by longitudinal elements.

The lateral arms11aof the structure10can be moved by sliding relative to each other on the cross beam11cso as to adjust their separation, as will be seen later.

To that end, the float of each lateral arm11aincludes a moving means13on the cross beam11cfor example formed by an assembly including guide rails and a rack-and-pinion system, not shown, and of a known type.

Moreover, the float of each lateral arm11ais equipped with locking means, not shown, on the cross beam11cso as to keep the separation between said lateral arms11aconstant and determined.

Thus as shown inFIGS. 1 and 3, the hull11includes, at its open portion, i.e. opposite the central arm11b, a door generally designated by reference15.

This door15is formed by two beam sections16opposite each other and movable by sliding each on a lateral arm11a.

The two beam sections16can be moved between a separated position, as shown inFIG. 3, in which they free the inlet of the structure10for the positioning of a vessel, a dock or a barge and a closed position of said inlet of the structure10, as shown inFIG. 1, in which they are closer together and in contact with each other.

To that end, each lateral arm11aof the hull11includes means17for moving each beam section16. This means17is for example formed by an assembly including guide rails and a rack-and-pinion system or using any other known means.

Lastly, each lateral arm11aalso includes a locking means, not shown, for locking the corresponding beam section16in the closed position or in the open position.

The hull11is equipped with legs20vertically movable relative to said floating hull11. In the embodiment shown in the figures, the hull11is equipped with four legs20arranged in pairs on each lateral arm11aof the hull11.

Each of the legs20for example has a triangular section as shown in the figures, or a square or circular section.

As appears in particular inFIGS. 5 and 6, each leg20is formed, traditionally, by three flanges21connected to each other by a mesh of metal girders22or by solid legs. Each leg20is combined with a mechanical movement means designated by a general reference numeral23.

The mechanical movement means23is housed in a supporting framework18, also called a “jack-house,” that is supported by the hull11.

As shown inFIGS. 5 and 6, the mechanical movement means23of each leg20comprises, on one hand, two opposite plates24each borne by a flange21of the corresponding leg20and including, each on each lateral face, a series of teeth24aforming a double rack on the two flanges21.

The mechanical movement means23also comprises several assemblies25distributed on either side of the plate24, along the height thereof. Each assembly25comprises a gear motor26ensuring the driving of a pinion27that meshes with a series of teeth24aof the corresponding plate24.

In the embodiment shown inFIGS. 5 and 6, the two series of teeth24aof each plate24are associated with six pinions27each driven in rotation by a gear motor group26.

The structure10also includes, combined with each of the legs20, a shuttle designated by general reference30that can be moved by the corresponding leg20between a lower position bearing on the floating hull11as shown inFIG. 1, and a higher position as shown inFIG. 3.

The shuttles30combined with the legs20are moved simultaneously by the legs20.

In the embodiment shown inFIG. 4, each shuttle30is formed by a body31including a vertical arm32extending substantially parallel to the flanges21of the corresponding leg.

The vertical arm32is formed by two parallel vertical beams32a.

The arm32is provided, on one hand, in its upper portion with a plate33extending substantially perpendicular to said arm32and, on the other hand, in its lower portion, a horizontal supporting base35for supporting a pair of higher and lower arms globally designated by reference60and70(FIG. 1), and that will be described later.

The plate33includes an opening34having a cross-section with a shape complementary to the transverse section of the corresponding leg20and, in the case at hand, a triangular-shaped cross-section. The plate33is connected to the base35by stiffening beams36.

Each shuttle30is provided with a locking means40for locking on the corresponding leg12and/or a set of small beams (not shown) situated on the upper portion of the shuttle30that are moved by sliding towards the inside of the shuttle30and the leg20that makes it possible, by raising the leg20upwards, to drive the corresponding shuttle30.

This locking means40, shown in more detail inFIG. 7, is formed by at least one counter-rack41for each plate24.

The counter-rack41can be moved by at least one actuating member42and, preferably, by two actuating members42for example formed by hydraulic or pneumatic jacks in order to move the counter-rack41between a retracted position and a locking position engaged on a series of teeth24aof the corresponding leg20.

The assembly formed by the counter-rack41and the actuating members42is carried by the plate33of each shuttle30.

The hull11also includes, at each leg20, a means50for guiding the corresponding shuttle30between the low (FIG. 1) and high (FIG. 3) positions, respectively.

As shown in theseFIGS. 1 and 3, the means50for guiding the shuttle30of each leg20comprises two vertical columns51extending vertically substantially parallel to the corresponding leg20. Each column51cooperates with a passage52formed in the base35of the shuttle30and each of these passages52has a section with a shape combined with the cross-section of the corresponding column51. The two columns51are connected to each other by a connecting plate53extending substantially perpendicular to said columns51that includes a central passage54(FIG.3) having a section with a shape complementary to the transverse cross-section of the corresponding leg20and, in the case at hand, a triangular cross-section. The connecting plate53forms a guide for the corresponding leg20.

During the movement of the shuttle30between the low position and the high position, by the leg20, the base35of the shuttle30is guided by the columns51and in the low position shown inFIG. 1, the plate31of the shuttle30bears on the upper end of each column51.

Generally, the transport structure10includes at least one support assembly for assembling a wind turbine1and preferably, as shown in the figures, two support assemblies each for a wind turbine1.

As shown inFIGS. 1 and 2, the wind turbine1is made up of a mast2bearing a nacelle3enclosing the electricity production means, not shown, driven by blades4a. The mast2is intended to be fitted into a base4, as shown inFIG. 14, for example, anchored on the sea bottom beforehand.

As shown inFIGS. 1 and 2, the mast2includes, in its upper portion, a collar5.

In reference now toFIGS. 1 and 2, we will describe an assembly for supporting a wind turbine1, the other support assembly of the other wind turbine1being identical.

The support assembly of the wind turbine1is made up of two shuttles30opposite each other and each combined with a leg20.

The shuttles30carry a pair of higher arms60and a pair of lower arms70.

The pair of upper arms60includes a first arm61borne by a first shuttle30and a second opposite arm62borne by a second shuttle30opposite the first shuttle30and the pair of lower arms70includes a first arm71borne by the first shuttle30and a second opposite arm72borne by the second shuttle30. The arms61and71can be moved by pivoting around a horizontal axis63borne by the first shuttle30and the arms62and72can be moved by pivoting around a horizontal axis64borne by the second shuttle30between a substantially vertical retracted position and an active position tilted against the mast of the wind turbine, as shown inFIGS. 1 and 2, for example.

The arms61and62of the pair60of higher arms each have a length substantially equal to the height of the mast2of the wind turbine1and the arms71and72of the pair70of lower arms have a length substantially equal to half the distance separating the inner edges of the two lateral arms11aof the hull11.

Alternatively, the arms61and62have a variable length that can be adjusted as a function of the height of the collar5on the mast2of the wind turbine. The arms are for example telescoping and provided with immobilization means for a given length.

The free ends of arms71and72of the pair70of lower arms include a gripping assembly for example formed by jaws73or by any other suitable gripping means of a known type.

As shown inFIGS. 8 and 9, the arms61and62of the pair60of upper arms include a means80for offsetting the horizontal movements of the hull11relative to the mast2after it is introduced in the base4and the tilting of the pair70of lower arms in the retracted position, as will be described later.

As shown in these figures, the offsetting means80includes a support assembly for supporting the mast2via the collar5. This support assembly includes a sliding means formed in a plate81provided with a U-shaped housing82and fastened to the free end of one of the arms of the pair60of higher arms and in particular the free end of the arm61of the pair60of higher arms. This plate81is intended to cooperate with a locking system83, of a known type, mounted at the free end of the arm62of the pair60of higher arms in the active position tilted against the mast2of the wind turbine1, as shown inFIG. 8. This U-shaped plate81is formed by a rail intended to receive rolling members85.

The U-shaped housing82of the plate81has a width larger than the diameter of the mast.

The sliding means of the support assembly of the mast2also comprises a platen90provided with a U-shaped housing91having a width substantially equal to the diameter of the mast2. This platen90can be moved on the plate81by the rolling members85along a horizontal plane substantially parallel to the support assembly of the mast. To that end, the lower face of the platen90includes three rails92forming a 120° angle between them.

The platen90includes a latch93for closing the U-shaped housing91and that can be moved between an open position making it possible to position the mast2inside the housing91of the platen90, as well as inside the housing82of the plate81and a closing position of the housing91, as shown inFIG. 8.

Thus, the sliding means of the support assembly formed by the plate81, the platen90and the rolling members85offset the horizontal movements of the hull11relative to the mast2when the latter part is introduced into the base4, and after the tilting of the pair70of lower arms in the retracted position in order to free the lower portion of the mast2relative to the hull11.

As an example and as shown inFIGS. 10 and 11, this sliding means allows the horizontal movement of the hull11in a direction fl without the mast2moving, as shown inFIG. 10or a horizontal movement of the hull11along a direction f2without the mast2of the wind turbine1moving.

This sliding means therefore prevents any transmission of stresses or strains in the base4, and any buckling of the mast2, after placement of the mast2of the wind turbine1in said base4.

According to the manner in which the wind turbine(s) is (are) placed in the structure10, the U-shaped housings82and91of the plate81and the platen90, respectively, are oriented perpendicular to the longitudinal axis of said hull11towards the open portion of said hull11.

Referring now toFIGS. 12 to 15, we will describe a first method for transport and installation of at least one wind turbine1.

First of all, the structure10is positioned near a loading zone for loading the wind turbine1with the legs20in the high position and the shuttles30in the low position bearing against the hull and with the arms61and62and the arms71and72, respectively, of the pair60of higher arms and the pair70of lower arms, in the substantially vertical retracted position, as shown inFIG. 12.

The wind turbine1is raised by a hoisting engine, such as a crane for example, and the mast2of the wind turbine1is placed between the lateral arms11a of the hull11, as shown inFIG. 12.

The arm61including the U-shaped housings82and91of the plate81and of the platen90is tilted in the active position to place the mast2in these U-shaped housings82and91below the collar5of the mast2. The arm62of the pair60of higher arms is then tilted in the active position and the arms61and62are secured to each other by the locking system83(FIG. 13). The U-shaped housing91of the platen90is closed by the latch93.

The mast2is lowered by the crane to make the collar5bear on the platen90, as shown inFIG. 13, and the arms71and72of the pair70of lower arms are simultaneously tilted to the active position to hold the mast2at its lower portion.

The placement of the second wind turbine on the structure10is done similarly.

The platen90is locked during the transport of the plate81.

The structure10bearing the wind turbine or two wind turbines1is moved to an installation site at which one or two bases4have been previously installed on the sea bottom.

The placement of the mast2of each wind turbine1on its corresponding base4is done as follows.

The legs20are lowered and each shuttle30is locked on the corresponding leg20.

These legs20are raised to lift the mast2using the shuttles30and pairs60and70of higher and lower arms, as shown inFIG. 14. The door15made up of sections16is open. The structure10is moved so as to position the mast2in alignment with the base4and the arms71and72of the pair70of lower arms are tilted to the retracted position, as shown inFIG. 14. The platen90is unlocked from the plate81.

Then, the legs20, the shuttles30and the pair60of higher arms are lowered to gradually engage the mast2in the base4. During this engagement, the horizontal movements of the hull10are offset by the offsetting means80provided on the pair60of higher arms such that the mast2still remains in a substantially vertical position.

The mast2is placed in the base4, and the arms60and61of the pair60of upper arms are unlocked and the latch93of the platen90is released to open the U-shaped housing91. The arms60and61are tilted to the retracted position, as shown inFIG. 15.

The structure10is then removed and another mast2is placed on the base4of a second wind turbine in an identical manner.

In reference now toFIGS. 16 to 19, we will describe another method for transport and offshore installation of one or two wind turbines in the case where the one or two wind turbines are on a pontoon8.

As shown inFIG. 16, the door15of the hull11is open and the legs20are placed in an intermediate position, while the shuttles30are placed in the low position bearing against the hull11.

In this case, the U-shaped housings82and91of the plate81and the platen90are oriented in the longitudinal axis of the hull11towards the open portion of the hull11. The arms71and72of the pair70of lower arms are in a substantially vertical retracted position.

The arms61and62of the pair60of higher arms at the front of the hull11are in a substantially vertical retracted position and the arms61and62of the pair60of higher arms situated at the back of the hull11are placed in an active position and locked to each other as shown inFIG. 17. The U-shaped housing91of the platen90is open.

The structure10is moved towards the pontoon8to place the pontoon8between the lateral arms11aof the hull11.

After the first wind turbine1passes beyond the first support assembly, as shown inFIG. 17, the arms61and62of the pair60of higher arms of the first assembly are tilted to the active position, as shown inFIG. 18, and the structure10is moved to engage the mast2of each wind turbine in the U-shaped housings82and91of the plate81and the platen90, respectively, as shown inFIG. 19.

The latch93of the U-shaped housing91of each platen90is closed and the arms71and72of the pair70of lower arms of each assembly are tilted simultaneously to grip each mast2at its lower portion.

Each shuttle30is locked on the corresponding leg20the legs20are raised to lift the shuttles30, and the pairs60and70of higher and lower arms are lifted by the shuttles30to bring the platen90of each assembly in contact with the collar5of the corresponding mast2.

The mast2of each wind turbine1is lifted from the pontoon8via shuttles30and pairs60of upper arms by raising the legs20, the pairs70of lower arms holding each mast2at its lower portion.

The legs20are then relowered to replace the shuttles in the low position bearing against the hull.

Each shuttle30is then unlocked from each corresponding leg20and the legs20are raised to the upper position, to minimize the draught.

Then, the structure10bearing the wind turbines1is moved to an installation site of each wind turbine1on its base4, previously installed on the sea bottom.

The installation of each wind turbine1is done as follows.

The legs20are raised to lift the mast2using shuttles30and pairs60and70of arms and the structure10is moved to position the mast2in alignment with the base4. The arms71and72of the pair70of lower arms are tilted to the retracted position and the same steps are carried out as in the preceding method.

Also in this case, when the mast2is engaged with the corresponding base4and after tilting of the pair70of lower arms, the horizontal movements of the hull are offset by the offsetting means80of the pair60of higher arms such that the mast2still remains in the substantially vertical position.

According to another method for placing one or two wind turbines on the hull11of the structure10, the one or two wind turbines can be mounted on the wagons moving on the rails. To that end, each wagon is equipped with pairs60and70of higher and lower arms in order to keep the wind turbine in a substantially vertical position. The wind turbines are positioned on the structure10by moving the wagon(s) by rolling on the rails between the pontoon and the structure10to position the pairs of arms bearing the wind turbine on the corresponding shuttles.

To transport and install an underwater generator, the same steps are carried out. But, in this case, the base does not extend past the surface of the water and, after placing the mast on its base, the nacelle containing the electricity producing means and bearing the blades is lowered below the surface of the water by sliding on its mast. For this application, the arms of the pair of higher arms have a length smaller than that provided for the installation of a wind turbine.

The structure for placement and installation of at least one wind turbine or at least one underwater generator has the advantage of preventing stresses or strains from having repercussions on the base due to the movements of the hull created by the swell.

The invention is not limited to the installation of wind turbines borne by the base4placed on the bottom of the expanse of water. Alternatively, the base4floats on the surface of the water and is anchored on the bottom of the expanse of water.