NL2003170C2

NL2003170C2 - Method of mounting or dismounting a windmill at sea and moveable platform to be used with said method.

Info

Publication number: NL2003170C2
Application number: NL2003170A
Authority: NL
Inventors: Johannes Antonius Seumeren; Nicolaas Lamphen
Original assignee: Mammoet Holding B V
Priority date: 2009-07-09
Filing date: 2009-07-09
Publication date: 2011-01-11

Description

Method of mounting or dismounting a windmill at sea and moveable platform to be used with said method

The invention relates to a method of mounting or dismounting a windmill at sea, which windmill comprises windmill parts selected from the group comprising a bottom section, a top section and a head section and rotorblades.

5 The invention is also related to a moveable platform for use in such a method to mount or dismount a windmill at sea.

For some decades it is known now to develop windmill parks at land. Such windmill parks are however disadvantageous in that they spoil the view. For that reason windmill parks are 10 most commonly applied distant from rural areas. This also applies to single windmills.

A further reason why windmill parks are placed distant from rural areas is that there is more wind available in open terrain, which increases the possibilities of operating a wind-15 mill or a windmill park efficiently in such an area. For this very reason and also for the reason to reduce people's resistance against the development of windmill parks or the placement of single windmills, such windmill parks are nowadays more frequently placed at sea. The placement of a windmill at sea, let 20 alone the placement of an entire windmill park at sea, is however prone with complications that relate to the placement of the windmills per se and furthermore relate to the maintenance of the windmills that are placed at sea. The invention is concerned with addressing these problems.

25 According to the invention a method of mounting or dis mounting a windmill at sea and a moveable platform for use in this method is proposed in accordance with one or more of the appended claims .

One of the aspects of the invention is to alleviate the 30 problem of how to transport the windmill in parts to and from the location at sea where the windmill is to be placed. In this connection a transportation of the windmill parts in accordance with the invention is proposed in which a top section of the windmill is provided with a frame on its top end, and that the 35 rotorblades are connected to said frame, while hanging down from 2 this frame adjacent to the top section. Although best results of the invention are believed to be attainable by transporting the windmill parts in this particular disassembled state, the applicant. considers that the proposed method of mounting or dismount-5 ing a windmill at sea can also be applied without this particular way of transporting the windmill parts to or from the site at which the windmill is to be erected.

An important aspect of the invention is that in the method of mounting or dismounting a windmill at sea the windmill 10 parts are handled individually and placed in their mounted or dismounted position by operating a knuckleboom crane that is placed on a movable platform. Such a knuckleboom came is known per se and is for instance known from http://www.huismanequipment.com/en.product/cranes/pedistal crane 15 s/knuckleboom. According to this website the knuckleboom crane is especially designed for the use in an off-shore environment and its tasks vary from construction pipe handling to subsea installation work. Albeit that the knuckleboom crane is known per se it has never been proposed to place it on a moveable plat-20 form, particularly on a jack-island, and use it for the mounting or dismounting of windmill parts in order to assemble or disassemble a windmill at sea.

This arrangement is however very beneficial and opens the way to mount or dismount a complete series of windmills in a 25 predefined area at sea at which a windmill park is to be located. The use of the moveable platform, preferably a jack-island, thus meets the requirement that an adequate and swift placement of windmills at selected sites at sea may be executed. Also the disassembling for maintenance purposes is with the use 30 of such a moveable platform in the form of a jack-island very easy to execute due to which maintenance of a windmill park at sea becomes indeed a feasible option.

The costs of the operation of placing the windmills or removing of the windmills from their site at sea can be kept at 35 acceptable levels by supplying or removing the windmill parts to or from the moveable platform by a marine vessel, preferably a ship.

In order to be able to execute the method of the invention with comparably simple equipment as compared to the equip- 3 ment that is used for placement of a windmill on land, the move-able platform of the invention has a knuckleboom crane that is provided with at least a gripper for holding a windmill's rotor-blade. The method of the invention can then preferably be car-5 ried out such that mounting or dismounting of a first, second or third rotorblade to or from the head-section is performed while said rotorblade and the corresponding part of the head-section are placed in the six o'clock position.

When the first rotorblade is placed or removed from the 10 head section, said head section is rotated so as to assume a position in which the next rotorblade can be placed or removed in said six o'clock position. In order to prevent adverse loads on the bearing or bearings of the head section it is preferred that at all times during mounting or dismounting from the second or 15 third rotorblade at said six o'clock position, the head-section supports at both the ten o'clock position and the two o'clock position other rotorblades and/or counterweights.

Effective handling of the rotorblades can be carried out by arranging that the gripper of the knockleboom crane on 20 the moveable platform is embodied as a clamp having two cooperating clamp-parts that are hingedly coupled to each other.

It is then preferred to prevent damage to the rotor-blade's surface that the gripper has an inner lining that is intended to follow the curvature of the rotorblade, which lining 25 is preferably selected from the group comprising synthetic rubber, caoutchouc, inflatable balloon.

The invention will hereinafter be further elucidated with reference to the drawing showing an exemplary embodiment of the platform of the invention and the embodiment according to 30 which the windmill parts are preferably transported.

In the drawing: - Figs. 1, 2 and 3 show a topview, sideview and frontal view, respectively of some windmill parts in a disassembled state and in a transportation position; 35 - Fig. 4-13 a series of subsequent steps performed in the method of the invention for mounting a windmill, and - Fig. 14 a sideview of a moveable platform in accordance with the invention supporting some windmill parts, - Fig. 15-18 the gripper forming part of the knuckle- 4 boom crane on the moveable platform of the invention in a series of operations aimed at holding a windmill's rotorblade.

Wherever in the figures the same reference numerals are applied these numerals refer to the same parts.

5 Referring first to Fig. 1, Fig. 2 and Fig. 3 some wind mill parts are shown in a disassembled state, however put together in accordance with the invention such that a top end of a top section 15 supports a frame 3 and rotorblades 1 are connected to said frame 3 in a manner that the rotorblades 1 hang 10 down from the frame 3 adjacent to the top section 15. This top section 15 is intended to be placed on a bottom section of the windmill whereby in the mounted condition the top section 15 will support the head section to which the rotorblades will be connected.

15 The manner of placing the top section 15 together with the rotorblades 1 as shown in Fig. 1, Fig. 2 and Fig. 3 in a topview, sideview and frontal view, respectively, can be beneficially used in the method of the invention of mounting or dismounting a windmill at sea, albeit that said method which is to 20 be discussed hereinafter can also be employed without the placement of the windmill parts in the transportation position as shown in Figs. 1, 2 and 3.

With reference now further to Fig. 14 the moveable platform of the invention is shown, generally carrying reference 25 numeral 11. This moveable platform 11 can be suitably applied in the method to mount of dismount a windmill at sea as to be discussed herein. For the purpose of employing the invented method, the moveable platform 11 has a supporting bearing 12 supporting thereon a knockleboom crane 13. At its free extremity the knock-30 leboom crane 13 is provided with a gripper 18, which is arranged for holding a windmill's rotorblade. Furthermore, the knockleboom crane 13 has winges 19 for lifting further loads.

The knockleboom crane 13 is embodied in a manner known per se such that it can rotate around the body axis of the sup-35 porting bearing 12 as well as perform movements in different planes that are orthonormally with respect to the said body axis of the supporting bearing 12. Furthermore, it is possible to rotate the gripper 18 around the longitudinal axis of the beam of the knockleboom crane 13 to which it is connected.

40 The platform 11 is embodied as a jack-island having 5 legs 17 that extend to the bottom of the sea. The platform 11 is moveable and in order to be able to exactly locate the position of the platform 11 it is provided with a positioning system such as GPS. Due to the platform 11 being mobile it is suited to 5 mount or dismount a series of windmills in a predefined area at sea, whereby the windmill parts 14, 15, 16 are supplied to the platform 11 or removed from said platform 11 by using a marine vessel such as a ship.

The windmill parts 14, 15 and 16 as shown on the plat-10 form 11 are preferably supplied or removed from such platform 11 in a disassembled state. In Fig. 14 the top section 15 is shown without the rotorblades 11 connected thereto in the transportation position as discussed hereinabove with reference to Figs.

1, 2 and 3. It will however be apparent to the man skilled in 15 the art that such a transportation arrangement can be suitably applied both for supplying the windmill parts 14, 15, 16 including the rotorblades to the platform 11 and for removal of said windmill parts from the moveable platform 11.

In all situations wherein the windmill parts 14, 15, 16 20 may be provided, that is with our without the rotorblades being attached to the top section 15 as shown in Fig. 1, 2 and 3, the handling of the rotorblades 1 can be performed with the gripper 18 being embodied as a clamp, the construction of which gripper 18 is more clearly shown in Figs. 15-18.

25 Fig. 15 shows a cross-section of a rotorblade 1 to gether with the clamp 18 in an open position. The clamp 18 comprises two cooperating clamp parts 22, 24 that are hingedly coupled to each other and are provided with an interlining 27 that suits the curvature of the rotorblade 1 as is clearly shown in 30 Figs. 16, 17 and 18.

For moving the two cooperating clamp parts 22, 24 from the open position shown in Fig. 15 to the closed position shown in Figs. 17 and 18, the clamp 18 is provided with hydraulic means 23 which upon actuation moves the two cooperating clamp 35 parts 22, 24 towards each other so that the clamp assumes the closed position as shown in Fig. 17.

The clamp 18 is further provided with secondary hydraulic means 25 which operate a lock 26 in order to secure that the 6 rotorblade 1 can be held without risk of undue opening of the clamp 18. The clamp 18 with the actuated lock is shown in Fig.

18 .

The inner lining 27 of the gripper 18 is preferably se-5 lected from the group comprising synthetic rubber, caoutchouc and an inflatable balloon. With these means unintended damaging of the rotorblade's surface can effectively be avoided.

Turning now to the method of mounting or dismounting a windmill at sea, in accordance with the invention, reference is 10 made to Figs. 4-13 showing several stages of the mounting procedure of a windmill at sea. It. will be apparent for the man skilled in the art that the dismounting of a windmill at sea is executed in essentially a reverse order so that a full description of a dismounting procedure can be dispensed with.

15 With co-reference to Fig. 14 the said Figs. 4-13 show the construction of a windmill at sea, which windmill comprises a bottom section 14, a top section 15, which may or may not be provided with the rotorblades attached thereto, and a head section 16 to which the rotorblades 1 are to be mounted.

20 The windmill parts 1, 14, 15, 16 are handled individu ally and placed in their mounted position by operating the knuckleboom crane 13 that is placed on the moveable platform 11.

Fig. 4 shows that first the bottom section 14 is placed on a subwaterlevel-section 19 of the windmill, which arises a 25 couple of meters above the level of the sea 10. For this purpose a first winge 21' of the knuckleboom crane 13 is used.

Fig. 5 shows that with another winge 21" the top section 15 is placed on the bottom section 14. Again, it is pointed out that although the top section 15 is shown without the rotor-30 blades connected thereto, such an arrangement as is shown in

Figs. 1, 2 and 3 can also be applied when the top section 15 is placed on the bottom section 14.

Fig. 6 shows that following the placement of the top section 15 the head section 16 to which the rotorblades are to 35 be mounted is placed again by using the topwinge 21".

When the placement of the head section 16 is carried out, the rotorblades 1 can be placed. The placement of the first rotorblade 1 is executed in a series of operations as reflected in Figs. 7-10, showing that the mounting of the first rotorblade 7 1 to the head section 16 is performed while the rotorblade 1 and the corresponding part of the head section 16 are placed in the six o'clock position. In this six o'clock position the rotor-blade 1 essentially points vertically downwards at a slight off-5 set angle with respect to an exact vertically oriented position.

The placement of the second and third rotorblade 1 into a connected position with the head section 16 is likewise performed while the concerning rotorblade and the corresponding part of the head section 16 are placed in the six o'clock posi-10 tion. This requires however that before the corresponding part of the head section that relates to the intended position of the second and third rotorblade is moved to the six o'clock position, said head section 16 is carefully balanced so as to prevent undue wear and tear of the bearing of said head section.

15 For this purpose the head section 16 is after the placement of the first rotorblade 1 first provided with counterweights 20 at the ten o'clock position and the two o'clock position as shown in Fig. 11. After the placement of the counterweights 20 the head section 16 can be rotated over 120° as shown in Fig. 12 20 following which the counterweight 20, which then occupies the six o'clock position can be removed and the second rotorblade 1 can be placed again in the six o'clock position as shown in Fig.

13.

The subsequent placement of the third rotorblade 1 can 25 in a similar fashion be carried out by first again rotating the head section further such that the first and second rotorblade come to occupy the ten o'clock and the two o'clock position.

The remaining counterweight 20 can then be replaced by the third rotorblade, which operation is carried out again with said ro-30 torblade and the corresponding part of the head section being placed in the six o'clock position.

The applicant cares to point out that the description as offered hereinabove with reference to the drawing of an exemplary embodiment is only intended to remove any ambiguity that 35 may reside in the claims, without intention to limit the scope of these claims to anything else then what accords to being the patentable contribution to the state of the art. The drawings and the description shall therefore not be construed and not be deemed to limit the claims to the particular embodiment shown 40 and discussed.

Claims

A method for mounting or dismantling an offshore windmill, which windmill comprises windmill parts selected from the group comprising a part (14), an upper part (15) and a head section (16) and rotor blades (1) with the Characterized in that the windmill parts (1, 14, 15, 16) are individually handled and placed in their mounted or disassembled position by using a knuckle boom crane (13) that is placed on a movable platform (11).

Method according to claim 1, characterized in that the movable platform (11) is a lifting platform and that supply or removal of the windmill parts (1, 14, 15, 16) to or from the lifting island is carried out with said windmill parts ( 1, 14, 15, 16) in a disassembled state.

3. Method as claimed in claim 2, characterized in that the supply or removal of the windmill parts (1, 14, 15, 16) to or from the lifting island (11) is carried out with a sea vessel, such as a ship.

4. Method as claimed in any of the claims 1-3, characterized in that the movable platform (11) is used for mounting or dismantling a series of windmills in a predetermined area at sea.

5. Method as claimed in any of the claims 1-4, characterized in that the mounting or dismantling of a first, second or third rotor blade (1) is carried out to or from the head section (16) while said rotor blade (1) and the corresponding part of the head section (16) are placed in the six o'clock position.

6. Method as claimed in claim 5, characterized in that during the mounting or dismantling of the second or third rotor blade (9) in the six-hour position, the head section (16) at both the 10-hour position and the two-hour position supports other rotor blades and / or counterweights (20).

Windmill parts in a disassembled state, comprising an upper part (15) and rotor blades (1), characterized in that the upper part (15) is provided with a frame (3) at its upper end, and that the rotor blades (1) are coupled to said frame (3) and hang down therefrom next to the upper part (15). - 9 -

A movable platform (11) for use in a method for mounting or dismantling a windmill at sea, characterized in that it carries a knuckle boom crane (13).

A movable platform according to claim 8, characterized in that the knuckle boom crane (13) is provided with a gripper (18) for holding a rotor blade (1) of a windmill.

10. Movable platform according to claim 9, characterized in that the gripper (18) is designed as a clamp (18) with two cooperating clamping parts (22, 24) which are hingedly coupled to each other and which are provided with an inner lining ( 27) which follows the curve of the rotor blade (1).

11. Movable platform according to claim 9 or 10, characterized in that the gripper (18) has an inner lining (27) which is adapted to follow the curve of the rotor blade (1), which lining is selected from the group comprising synthetic rubber, rubber, inflatable balloon.

12. A movable platform according to any one of claims 9-11, characterized in that the gripper (18) is provided with a releasable closure (26) for securing the retention of a rotor blade (1).