CRANE FOR A WIND FARM INSTALLATION VESSEL

Abstract

The invention relates to a crane as a component of a wind farm installation vessel which consists of a vessel body and a plurality of jack-up legs arranged in vertically movable manner thereon, wherein the crane is arranged rotatably about one of the jack-up legs. According to the invention, the crane is rotatably mounted on an eccentric platform which itself is arranged rotatably about the jack-up leg.

Claims

1. A crane as a component of a wind farm installation vessel which consists of a vessel body and a plurality of jack-up legs arranged in vertically movable manner thereon, wherein the crane is arranged rotatably about one of the jack-up legs, wherein the crane is rotatably mounted on an eccentric platform which itself is arranged rotatably about a jack-up leg.

2. The crane according to claim 1, wherein the eccentric platform comprises on one side a cutout through which the jack-up leg is passed, and in that it rotatably receives the crane on an opposite side.

3. The crane according to claim 1, wherein the eccentric platform is rotatable about the jack-up leg by way of a slewing gear mounted on a vessel side, wherein the slewing gear too comprises a preferably central cutout through which the jack-up leg is passed.

4. The crane according to claim 1, wherein the crane is rotatably received by way of a slewing gear at a freely projecting end of the eccentric platform.

5. The crane according to claim 3, wherein the jack-up legs can be extended and retracted by way of drive units arranged on the vessel body.

6. The crane according to claim 5, wherein the slewing gear for receiving the eccentric platform is arranged on one of the drive units, optionally by way of an adapter.

7. The crane according to claim 3, wherein the crane has a turntable which is connected to the slewing gear, wherein a jib and at least one guy support frame are articulated directly or indirectly on the turntable.

8. The crane according to claim 1, wherein the jack-up legs and/or a crane jib are formed as a lattice mast.

9. The crane according to claim 1, wherein a stowage frame for receiving a stowed free jib end in a transport position is provided on the vessel.

10. A wind farm installation vessel having a crane according to one of claim 1.

Description

[0029] Further features, details and advantages of the invention will be discussed with reference to an example of embodiment illustrated in the drawings. Therein:

[0030] FIG. 1: is a perspective view of a wind farm installation vessel illustrated in simplified manner with a crane according to the invention according to one example of embodiment of the invention,

[0031] FIG. 2: is a different perspective view of the wind farm installation vessel of FIG. 1, in which the slewing radii of the crane are clearly shown,

[0032] FIGS. 3, 4 and 5: are further illustrations of the wind farm installation vessel of FIG. 1 with different positions of the crane, and

[0033] FIG. 6: is an illustration of the wind farm installation vessel of FIG. 1, in which the crane is stowed in a transport position.

[0034] FIG. 1 shows a simplified representation of a wind farm installation vessel 10. Such wind farm installation vessels are also referred to as installation ships or, according to the English term, jack-up vessels. In conventional manner, the wind farm installation vessel has jack-up legs 14 arranged in each case laterally in the front and rear region of the vessel body 12. These jack-up legs 14 in the representation of FIG. 1 are illustrated in the travelling position of the wind farm installation vessel. This means that these jack-up legs 14, which in themselves are arranged vertically movably, are arranged in a position projecting upwards over the deck 16. In this position, the wind farm installation vessel 10 typically travels at a speed of up to 15 knots or more, by means of the ship's propulsion units, which are not illustrated in greater detail here.

[0035] On reaching the desired position in which the structure, for example a wind turbine, is to be erected offshore, the wind farm installation vessel is anchored to the sea bed by the jack-up legs 14 being moved vertically by drives 18, not illustrated in greater detail here, vertically downwards beneath the vessel body until they hit the sea bed. The jack-up legs 14 in this case, after hitting the sea bed, are used as supports in order to raise the entire vessel body 12 approximately 10-20 meters above the sea surface. In this working position, usually the lift crane 20 provided is then used.

[0036] As can be seen in particular from FIG. 2, the lift crane 20 is a conventional maritime heavy-lift crane, which can bear up to approximately 3000 t. The crane has a long jib 22, which is pivotably articulated on a turntable 24. The turntable 24 in turn is mounted on a slewing gear 26. The jib 22 in the example of embodiment illustrated here has a guy support frame 28, 30. In the present example of embodiment, an individual jib 22 is shown as a lattice jib. However, multi-part lattice jibs may also be used here, as illustrated for example in U.S. Pat. No. 5,580,189.

[0037] The entire crane 20 is mounted on an eccentric platform 32, as shown in FIG. 2. This eccentric platform has on one side a large cutout 34 through which the jack-up leg is passed. On the opposite, freely projecting, side, the eccentric 32 bears the slewing gear 26 for the crane 20. The eccentric 32 is rotatably mounted by way of a slewing gear 36, which likewise has a central cutout through which the jack-up leg is passed. In this case, the lifting mechanism 36 is constructed by way of an adapter 38 on the drive unit 18 of the jack-up leg 14.

[0038] Owing to the method of construction previously described, the crane 20 can first of all be turned about its own axis of rotation by means of the slewing gear 26. Additionally, it can be turned parallel to this own axis of rotation about a second axis of rotation, namely the axis of rotation of the eccentric 32, which coincides with the axis of symmetry of the jack-up leg 14. Thus the radius r.sub.Kran, as marked in FIG. 2, is yielded for the slewing radius of the crane itself. The total slewing radius r.sub.ges is then yielded by superposition of the slewing radius of the crane r.sub.Kran and the slewing radius of the eccentric r.sub.Exzenter.

[0039] Different positions of the crane which are produced by superposition of the slewing radii r.sub.Exzenter and r.sub.Kran are illustrated in FIGS. 1-6. As can be recognized using this exemplified positioning, here even when the jack-up legs 14 are extended, as are shown in the illustrations present here, virtually all the regions in the vicinity of the vessel body can be reached with the crane hook.

[0040] The position of the crane according to FIG. 1, in which the crane 20 is moved across the eccentric platform 32 into an outer position next to the hull, is particularly advantageous. Here, the wind farm installation vessel can be loaded and unloaded by means of an external crane without colliding.

[0041] In FIG. 6, the crane is illustrated in a typical transport position, in which the jib 22 lies on a stowage frame 40. The stowage frame 40 in the example of embodiment present here is constructed on a vessel superstructure 42, which for example represents the bridge of the wind farm installation vessel 10.