DK181736B1

DK181736B1 - A platform for a wind turbine tower part and method for sealing a platform

Info

Publication number: DK181736B1
Application number: DKPA202370203A
Authority: DK
Inventors: Duarte Matias Angelo Filipe; Fisker Jensen Jacob
Original assignee: Ramboell Danmark As
Priority date: 2023-04-26
Filing date: 2023-04-26
Publication date: 2024-11-13
Also published as: DK202370203A1

Abstract

A platform (6) for a wind turbine tower part (7) is disclosed. The platform (6) comprises a flexible sealing member (8), wherein a first end (9) of the flexible sealing member (8) is connected to the platform (6) at a periphery (10) of the platform (6). The platform (6) also comprises at least one bracket (11) connected to the platform (6) at the periphery (10) of the platform (6), and a number of seal expansion members (12), wherein each of the seal expansion members (12) are connected to a second end (13) of the flexible sealing member (8) and each of the number of seal expansion members (12) are displaceably connected to a bracket (11) of the at least one bracket (11). A method for sealing a platform (6) inside a wind turbine tower part (7) is also disclosed.

Description

DK 181736 B1 1

A PLATFORM FOR A WIND TURBINE TOWER PART AND A METHOD FOR SEALING A

PLATFORM

Background of the invention

S The invention relates to a platform for a wind turbine tower part and a method for sealing a platform inside a wind turbine tower part.

Description of the Related Art

Large modern wind turbines usually comprise a rotor held by a nacelle, wherein the nacelle is placed on a tower part. Onshore, the tower part 1s usually just some sort of tubular tower found directly on land, but offshore the tower part usually also comprises a foundation substructure — such as a monopile, a jacket or other — wherein a transition piece often is arranged between the upper tubular tower and the foundation or arranged at the connection between the upper tubular tower and the 13 foundation. Typically, the wind turbine tower part and/or the foundation substructure require a set of internal platforms- eg, inside the upper tubular tower, the foundation and/or the transition piece — these aim to support wind turbine installation and operational and maintenance equipment, providing easy access for personnel to important parts of the tower part or other.

However, inside e.g, a monopile foundation, seawater and moist is typically present, which may cause damage to the inside of the tower parts and any electrical equipment inside the tower — e.g., on the platforms. The extension of the tower part above a bottom platform and subsequently, any equipment therein} can be protected from being adversely affected by moisture, toxic fumes or other issues derived from proximity and contact with the seawater, by aiming for airtightness at this interface.

Typically, this 1s achieved at the lowest “accessible” level of the tower part by welding a steel element (or welded seal support) to the internal surface of the tower part wall, throughout its complete perimeter. The welded part to the tower part and other closing mechanisms on top of this element should then allow for some sort of

DK 181736 B1 2 airtightness — dividing the internal volume of the foundation in two different atmospheres (1e., a first in contact with seawater and a second controlled environment). This solution, however, due to welding on the primary structure, introduces stress concentration areas/hot-spots, which are structurally undesirable, especially in relation to fatigue strength of the structure. Furthermore, eg. monopiles are usually rammed or vibrated into the seabed, meaning that a welded attachment causes increased fatigue damage in the tower part, and subsequently results in increased plate thickness requirements, hence cost. Even though fatigue in this area 18 critical mainly during installation of the tower part, fatigue must naturally be considered in all aspects of the lifetime of an offshore wind turbine.

Thus, from the European patent EP 3 438 449 B1 it is known to place the bottom platform in a monopile of a tower part after the ramming process and then provide sealing means for sealing the upper portion of the tower part from the bottom portion of the tower part. And from the international patent application WO 2011/163585 Al and the European patent application EP 4 015 816 Al it is known to form such a seal by means of an inflatable tube. However, inflatable tubes are vulnerable and tend to deflate over time.

An object of the invention is therefore to provide for a more cost-efficient platform sealing technique.

The invention

The invention provides for a platform for a wind turbine tower part. The platform comprises a flexible sealing member, wherein a first end of the flexible sealing member is connected to the platform at a periphery of the platform. The platform also comprises at least one bracket connected to the platform at the periphery of the platform, and a number of seal expansion members, wherein each of the seal expansion members are connected to a søcond end of the flexible sealing member

DK 181736 B1 3 and each of the number of seal expansion members are displaceably connected to a bracket of the at least one bracket.

Forming the seal by means of a flexible sealing member is advantageous in that this

S member can be formed sturdy and durable and given its flexible nature, it can be arranged in both a handling/installation state - at which the flexible sealing member is retracted to ensure a smaller outer diameter of the seal during installation — and in a sealing state at which the seal is expanded to seal against the inside wall of a wind turbine tower part. Furthermore, the flexible sealing member also enables that — variations (tolerances) — up to a certain size — of the distance between the platform periphery and the inside wall of the wind turbine tower part can be accepted.

Providing a platform with a number of seal expansion members connected to brackets at the periphery of the platform is advantageous, in that when the seal expansion members are connected to a second end of the flexible sealing member, — the seal expansion members can individually expand the flexible sealing member to its sealing state by being displaced in relation to the brackets, hereby ensuring a secure and well adapted seal.

Finally, by using a sealing technique according to the invention, welding of platforms (which could be referred to as "secondary structures") onto the tower part is not needed, whereby concentration of stresses at the welded joint between the platform and tower part (usually also referred to as the “primary structure”) are avoided. This is advantageous in that foundation installation imposes less fatigue damage on the primary structure such that material and engineering costs is greatly reduced.

Avoiding welds is further advantageous in that weld material, inspection and testing is not needed/used. Furthermore, fabrication defects and thereby delays due to e.g, tack of proper welding techniques/qualifications are reduced. These are all factors contributing to the reduction of fabrication costs. Since the invention may be related

DK 181736 B1 4 to mass-produced components, the fabrication costs are therefore further reduced by the scaling effects. “Primary structures” are usually understood as being the load carrying structure, i.e,

S paris carrying loads from the wind turbine and environmental loads, 1.0., wind, waves, currents, ice, etc. "Secondary structures” are usually understood as components attached to the primary structure which do not compromise the structural integrity of the entire structure in case of collapse (e.g., boat landing, platforms, ladders, monitoring equipment etc).

Thus, the invention allows for separate manufacturing/fabrication of the primary steel and secondary structure in that no secondary structure attachment on the primary structure is necessary. Therefore, the primary structure and secondary structure can be fabricated at different manufacturing facilities being specialized in fabricating each part of the structure, making the fabrication more efficient. Also, in this regard, the primary structure is not influenced by the secondary structure in relation to structural design.

In an aspect of the invention, the flexible sealing member is extending along the — entire periphery of the platform.

Making the flexible sealing member extend along the entire periphery of the platform is advantageous in that the diameter difference of the platform with a flexible sealing member in collapsed state (handling state) and in an expanded state (sealing state) hereby becomes bigger — making it easier to install the platform in the wind turbine tower part. Furthermore, it is hereby easier to form a tight seal — as opposed to e.g. a flexible sealing member divided into two or more parts where the joints between the parts would also have to be sealed - or a flexible sealing member only extending partly around the periphery of the platform where the free ends of the flexible sealing member would also have to be sealed against something.

DK 181736 B1

In an aspect of the invention, the number of seal expansion members are displaceably connected to the at least one bracket so that the seal expansion members can be displaced in a plane substantially parallel to a top surface of the platform. 5

Arranging the seal expansion members so that they are displaced in a plane substantially parallel to a top surface of the platform — i.e, horizontally in a normal erected wind turbine tower part - from the brackets is advantageous in that it hereby is possible to firmly press the second end of the flexible scaling member against the inside wall of the wind turbine tower part to form a tight seal in a simple manner.

Furthermore, this horizontal expansion of the seal expansion members also ensures firm horizontal support of the platform to thereby better stabilize its position in the wind turbine tower part. — In an aspect of the invention, the number of seal expansion members are arranged to expand in a radial direction away from a central part of the platform.

Arranging the seal expansion member to expand in a radial direction away from a central part of the platform is advantageous in that the seal expansion members hereby can press the flexible sealing member firmly against the inside wall of the wind turbine tower part and the seal expansion members will provide better horizontal support to the platform.

In an aspect of the invention, the number of seal expansion members are configured — to structurally support the platform in a horizontal direction in the wind turbine tower part.

Arranging the seal expansion members to structurally support the platform in a horizontal direction in the wind turbine tower part is advantageous in that the seal

DK 181736 B1 6 expansion members hereby also will aid in stabilizing the position of the platform inside the wind turbine tower part. it should be noted that any reference to orientation throughout this document — such as horizontally, vertically, up, down, top, bottom, upper, lower, side etc. — refers to the normal orientation in an erected, substantially vertically extending wind turbine tower part as it would be oriented during normal operation of a wind turbine.

In an aspect of the invention, the number of seal expansion members comprises an elongated rod having external thread, wherein the at least one bracket comprises a nut member having internal thread and wherein the number of seal expansion members are displaceably connected to the at least one bracket through engagement of the external thread and internal thread. 18 Displaceably connecting the seal expansion members to the bracket or brackets through mutually engaging threaded parts is advantageous in that it hereby is easy to displace the seal expansion members in relation to the brackets by rotating the elongated rod or rotating the nut member. Furthermore, such engaging threaded parts also enable that the seal expansion members can press the flexible sealing member — against the wind turbine tower part more forcefully and that the expansion of the seal expansion members can be controlled and adjusted more precisely.

In an aspect of the invention, the number of seal expansion members are connected to the second end of the flexible sealing member through a clamping plate.

Making the seal expansion members act on the flexible sealing member through a clamping plate is advantageous in that the flexible sealing member hereby can be pressed against the inside wall of the wind turbine tower part over a larger area hereby forming a tighter seal and reducing a nisk of tearing the flexible sealing member by distributing the pressing/clamping force from the seal expansion member.

In an aspect of the invention, the first end of the flexible sealing member is

S connected to the platform by means of the at least one bracket.

Connecting the first end of the flexible sealing member to the platform by means of the bracket or brackets is advantageous in that it makes it easier to connect the flexible sealing member to the platform and it enables that a tight seal between the platform and the flexible sealing member more easily can be formed.

In an aspect of the invention, the flexible sealing member is made of a polymer material such as neoprene. 18 Polymer material such as neoprene is a flexible, durable, waterproof, and airtight material particularly suited for forming a flexible sealing member.

In an aspect of the invention, the flexible sealing member comprises an upper side and a lower side, and wherein the number of seal expansion members are arranged at — the upper side of the flexible sealing member.

Arranging the seal expansion members above the flexible sealing member is advantageous in that the seal expansion members hereby is protected from the corrosive environment below the flexible sealing member. Furthermore, by placing — the seal expansion members at the upper side of the flexible sealing member the seal expansion members can easier be monitored during the expansion process and inspected subsequently.

DK 181736 B1 8

In an aspect of the invention, the flexible sealing member comprises an upper side and a lower side, and wherein the number of seal expansion members are arranged at the lower side of the flexible sealing member.

S Arranging the seal expansion members below the flexible sealing member 13 advantageous in that the flexible sealing member hereby forms a natural rim around the platform protecting personnel from tripping over the seal expansion members.

In an aspect of the invention, the platform comprises connection members projecting from a top surface of the platform, wherein the connection members are arranged for suspending the platform from the wind turbine tower part. if the platform has to be arranged inside the wind turbine tower part at a position vertically displaced from a connection between different parts of the wind turbine tower part, the platform can be held in this position by dedicated supports arranged at this specific location - which is not desirable in that such dedicated supports arranged away from the joints between different parts of the wind turbine tower part will weaken the wind turbine tower part and/or increase cost. Thus, it is advantageous to provide the platform with connection members projecting from a top surface of the platform in that the upper end of these connection members can be connected to a connection between different parts of the wind turbine tower part and thereby enable that the platform may be vertically displaced in relation to this tower part joint — i.e. enabling that the platform is suspended and hanging in the wind turbine tower part.

The invention further provides for a method for sealing a platform inside a wind turbine tower part. The method comprises the steps of e connecting a first end of a flexible sealing member to the platform at a periphery of the platform, e connecting at least one bracket to the platform at the periphery of the platform,

DK 181736 B1 9 s connecting a second end of the flexible sealing member to a number of seal expansion members, s connecting each of the number of seal expansion members displaceably to the at least one bracket, s placing the platform inside a wind turbine tower part, and e displacing the number of seal expansion members outwards in relation to the at least one bracket to press the second end of the flexible sealing member against an inside wall of the wind turbine tower part.

Connecting a first end of a flexible sealing member to the platform, connecting the bracket or brackets to the platform, connecting a second end of the flexible sealing member to the seal expansion members, and connecting each of the seal expansion members displaceably to the bracket or bracket before the platform is placed inside the wind turbine tower part is advantageous in that this ensures that the platform and 13 its sealing parts can be assembled in a more controlled environment — such as a platform manufacturing plant or other. Furthermore, displacing the number of seal expansion members outwards to press the flexible sealing member against an inside wall of the wind turbine tower part after the platform is placed inside the wind turbine tower part is advantageous in that the outer diameter of the platform hereby is reduced while it is being placed in the wind turbine tower part — hereby reducing the risk of the platform colliding with the wind turbine tower part and enabling that the platform can be navigated/lowered through a smaller opening, such as through an opening in a top flange of the wind turbine tower part — while at the same time ensuring that once the platform is in position inside the wind turbine tower part the — flexible sealing member may easily, forcefully, and precisely be expanded to seal the gap between the periphery of the platform and the inside wall of the wind turbine tower part.

In an aspect of the invention, the number of seal expansion members comprises an elongated rod having external thread, wherein the at least one bracket comprises a

DK 181736 B1 10 sut member having internal thread, wherein the external thread is engaging the internal thread and wherein the number of seal expansion members are displaced outwards in relation to the at least one bracket by rotating the elongated rod or rotating the nut member.

Displaceably connecting the seal expansion members to the bracket or brackets through mutually engaging threaded parts and then displacing the seal expansion members outwards by rotating the elongated rod or rotating the nut member is advantageous in that it hereby easy and forcefully presses the flexible sealing member against the wind turbine tower part in a controlled and precise manner. in an aspect of the invention, the wind turbine tower part comprises a flange connection, the flange connection comprising a lower connection flange and an upper connection flange and wherein the method further comprises the step of suspending the platform from the upper connection flange or the lower connection flange.

Suspending the platform from an upper connection flange or a lower connection flange of a flange connection between vertically joined parts of the wind turbine tower part is advantageous in that it hereby is possible to connect the platform to the wind turbine tower part without weakening the wind turbine tower part while it at the same time is possible to position the platform vertically away from the flange connection.

In an aspect of the invention, the platform is a platform according to any of the previously discussed platforms.

Hereby is achieved an advantageous embodiment of the invention.

Figures

The invention will be described in the following with reference to the figures in which fig. I illustrates a large modem offshore wind turbine comprising a wind turbine tower part, as seen from the front, fig. 2 tlustrates a cross section through the middle of a wind turbine tower part and a platform before expansion of the flexible sealing member, as seen in an isometric view, fig. 3 tlustrates a cross section through the middle of a wind turbine tower part and a platform before expansion of the flexible sealing member, as seen from the front, 18 fig. 4 illustrates a cross section through the middle of a wind turbine tower part and a platform after expansion of the flexible sealing member, as seen in an isometric view,

IfFe.5 illustrates a cross section through the middle of a wind turbine tower part and a platform after expansion of the flexible sealing member, as seen from the front, fig. 6 illustrates a closeup of a platform with a flexible sealing member before expansion of the flexible sealing member, as seen from the front, fig. 7 ltustrates a closeup of a platform with a flexible sealing member after expansion, as seen from the front, and

DK 181736 B1 12 fig. 8 slustrates a closeup of a platform with a reversed flexible sealing member after expansion, as seen from the front.

Detailed description of related art

S Fig 1 illustrates a large modern offshore wind turbine 1 as known in the art, comprising a wind turbine nacelle 3 positioned on top of wind turbine tower part 7.

A wind turbine rotor 4 - in this case comprising three wind turbine blades 5 - is mounted on a common hub which is connected to the nacelle 3 through a shaft extending out of the nacelle 3 front. In another embodiment the wind turbine rotor 4 could comprise another number of blades 5 such as one, two, four, five or more.

Also, the offshore wind turbine I could comprise several rotors, also known as multi- rotor wind turbines.

In this embodiment the wind turbine tower part 7 comprises an upper tubular tower 2 18 which to a great extent is common for all onshore and offshore wind turbines 1 — however obviously adapted to the specific size, manufacturer, location, foundation type and other. In this embodiment the upper tubular tower 2 is placed on top of - and connected to - a transition piece 28 forming part of the wind turbine tower part 7 and the transition piece 28 is in turn placed on top of — and connected to — a monopile foundation 29 also forming part of the wind turbine tower part 7. However, in another embodiment the wind turbine tower part 7 could comprise only the upper tubular tower 2, it could comprise only the upper tubular tower 2 and the monopile foundation 29 — i.e, no transition piece, it could comprise only the upper tubular tower 2 and another form of offshore foundation such as jacket, a tripod, a floating structure or other - with or without a transition piece 28 - or the wind turbine tower part 7 could be formed in numerous other ways known to the skilled person.

A monopile foundation 29 is typically rammed into the seabed (not shown) and it is therefore not desirable to weld brackets, ladders, boat landings, anodes, fixtures or other onto the monopile 29 as this would introduce large stress concentrations in the

DK 181736 B1 13 monopile still which is undesirable as regards fatigue, and there is a risk that these additional elements would loosen or be damaged during the ramming process. Thus, in this embodiment the bottom part of the transition piece 28 is overlapping the upper part of the monopile 29, so that ladders, boat landings, platforms and other can be

S connected to the transition piece 28 before installation and thereby installed along with the transition piece 28. However, as explained above offshore wind turbine tower parts 7 exists in a multitude of variations known to the skilled person.

Fig. 2 illustrates a cross section through the middle of a wind turbine tower part 7 and a platform 6 before expansion, as seen in an isometric view and fig. 3 illustrates a cross section through the middle of a wind turbine tower part 7 and a platform 6 before expansion, as seen from the front.

In this embodiment the wind turbine tower part 7 is similar to the wind turbine tower 18 part 7 shown in fig. f. Le, in this embodiment a monopile 29 is first rammed into the seabed and thereafter the transition piece 28 is placed on the monopile 29 and the two are connected by means of a flange connection 25 which in this case comprises a lower connection flange 26 formed at the upper end of the monopile 29 and an upper connection flange 27 forming part of the transition piece 28. However, in another embodiment the flange connection 25 could be formed between the upper tubular tower 2 and the monopile 29, between the upper tubular tower 2 and the transition piece 28, between tower segments of the upper tubular tower 2 or other.

Once the transition piece 28 is connected to the monopile 29 a platform 6 is lowered down through the transition piece 28 and down into the monopile 29. However, in another embodiment the platform 6 could be lowered down into the monopile 29 before the transition piece 28 is connected to the monopile 29. During the lowering process the flexible sealing member 8 along the platform periphery 10 is collapsed as disclosed in figs. 2 and 3 so that the outer diameter of the platform 6 is small enough forthe platform 6 to pass down through the flange connection 25.

DK 181736 B1 14

In this embodiment the platform 6 is provided with eight connection members 23 projecting upwards from the top surface 14 of the platform 6 and once the platform 6 is in place in the monopile 29 the connection members 23 are in this case connected

S$ to the upper connection flange 27 by means of welding so that the platform 6 hereby is suspended inside the wind turbine tower part 7. However, in another embodiment the platform 6 could also or instead be connected to the wind turbine tower part 7 by means of screws, bolts, interlocking geometry, clamping or other or the connection members 23 could merely rest on the flange connection 25 or other suitable surfaces inthe wind turbine tower part 7.

In this embodiment the connection members 23 are formed by steel pipes and plates but in another embodiment the connection members 23 could also or instead comprise chains, wires or other and/or in another embodiment the platform 6 could comprise another number of connection members 23 — such as three, six, ten, fifteen or other.

In another embodiment the connection members 23 could instead be projecting downwards from the platform 6 and/or the wind turbine tower part 7 could be provided with platform brackets or other for suspending the platform so that the connection members 23 could be omitted.

In this embodiment the platform 6 is provided with a flexible sealing member 8 in the form of a flexible, circular tarpaulin extending along the entire periphery 10 of the platform 6 and made of a polymer material which in this embodiment is neoprene. However, in another embodiment the flexible sealing member 8 could also or instead be made from another polymer material such as natural or artificial rubber, polyester or polypropylene — e.g, fibre reinforced - and/or the flexible sealing member 8 could at least partly comprise none-polymer material such as metal or other. Also, in another embodiment parts of the periphery 10 of the platform 6 could

DK 181736 B1 15 be sealed by other means and the flexible sealing member 8 would therefore only extend along parts of the periphery 10 of the platform 6 and/or the platform 6 could comprise more than one flexible sealing member 8.

S In this embodiment a first end 9 of the flexible sealing member 8 is connected to the platform 6 at the periphery 10 of the platform 6 and a second end 13 of the flexible sealing member § is connected to a number of seal expansion members 12. In this embodiment each seal expansion member 12 is displaceably connected to a bracket 11 enabling that the seal expansion members 12 and thereby the second end 13 of the flexible sealing member & can be displaced radially outwards,

In this embodiment each seal expansion member 12 is displaceably connected to its own individual bracket 11 connected to the periphery 10 of the platform 6 but in another embodiment more than one seal expansion member 12 could be connected to each bracket 11 or if e.g, the bracket 11 was formed as a full ring, all the seal expansion members 12 could be connected to the same bracket 11. In this embodiment the brackets 11 are connected to the platform 6 by means of welding but in another embodiment they could also or instead be connected by means of screws, bolts, rivets or other or the brackets 11 could at least partly be formed integrally with — the platform structure.

Fig. 4 illustrates a cross section through the middle of a wind turbine tower part 7 and a platform 6 after expansion, as seen in an isometric view and fig. 5 illustrates a cross section through the middle of a wind turbine tower part 7 and a platform 6 after expansion, as seen from the front.

Once the platform 6 is in its correct vertical position inside the wind turbine tower part 7, the flexible sealing member 8 is expanded by rotating the seal expansion members 12 in the brackets 11 to move the second end 13 of the flexible sealing member 8 outwards so that it finally presses firmly against the inside wall 24 of the

DK 181736 B1 16 wind turbine tower part 7. When all the seal expansion members 12 presses against the inside wall 24 of the wind turbine tower part 7 the seal expansion members 12 will also structurally support the platform 6 in the horizontal direction to thereby prevent horizontal movement of the platform 6 in relation to the wind turbine tower part?

Fig. 6 illustrates a closeup of a platform 6 with a flexible sealing member § before expansion, as seen from the front.

In this embodiment the first end 9 of the flexible sealing member 8 is connected to the platform © by means of fixing plates 30 clamping the first end of the flexible sealing member & between the fixing plates 30 and the brackets 11 so that the first end 9 of the flexible sealing member 8 in this embodiment is connected to the platform © by means of the brackets 11. However, in another embodiment the first 18 end © of the flexible sealing member 8 could be connected directly to the platform 6, it could be connected by dedicated connection brackets or fixtures or other and/or the first end 9 of the flexible sealing member 8 could instead of clamping be connected by means of adhesive, screws, rivets or other.

Fig. 7 illustrates a closeup of a platform 6 with a flexible sealing member 8 after expansion, as seen from the front.

In this embodiment the seal expansion members 12 comprise an elongated rod 16 having external thread 17 and the bracket 11 comprises a nut member 18 in the form of a through hole having internal thread 19. Le, in this embodiment the seal expansion member 12 is displaceably connected to the bracket 11 by the external thread 17 engaging the internal thread 19 and in this embodiment a pair of additional nuts are provided on the seal expansion member 12 to lock the seal expansion member 12 in correct position once the seal expansion member 12 is extended into its correct position at which it is pressing the flexible sealing member 8 against the

DK 181736 B1 17 inside wall 24 of the wind turbine tower part 7. Le, in this embodiment the seal expansion members 12 are arranged to expand in a radial direction away from a central part 15 (see fig. 4 and 5) of the platform 6.

S In this embodiment the seal expansion members 12 are connected to the second end 13 of the flexible sealing member 8 through a clamping plate 20 having a curvature substantially corresponding to the curvature of the inside wall 24 of the wind turbine tower part 7. However, in another embodiment the seal expansion members 12 could be connected directly to the flexible sealing member 8 and/or the clamping plate 20 could be formed differently and/or the seal expansion members 12 could be connected to the flexible sealing member 8 through other means.

In this embodiment the seal expansion members 12 are rotatably connected to the clamping plates 20 to allow that the seal expansion member 12 can be displaced in relation to the brackets 11 by rotating the seal expansion members 12. However, as disclosed in relation to fig. 8, in another embodiment the seal expansion member 12 could be arranged to extend through an untreaded hole in the bracket and the seal expansion member 12 would be displaced in relation to the brackets 11 by rotating separate mut members 18 engaging the external thread 17 of the seal expansion member 12. Le., in such an embodiment the seal expansion member 12 would not have to be rotatable. However, the seal expansion members 12 could displaceably connected to the brackets 11 in numerous other ways — i.e., in another embodiment the seal expansion members 12 could be provided with an external barb-like structure and the bracket 11 would comprise e.g., a nylon collar through which the seal expansion member 12 would extend so that it could be displaced by striking the free end of the seal expansion member 12 and the external barb-like structure would prevent the seal expansion member 12 from moving in the opposite direction. Or the brackets 11 could provided with one or more set screws pressing against the side of the seal expansion member 12 to lock the seal expansion member 12 in its correct position. In such an embodiment the force needed for expanding the flexible sealing

DK 181736 B1 18 member 8 and pressing it against the inside wall 24 of the wind turbine tower part 7 would have to provided through additional means — such as a dedicated pressing tool.

In another embodiment a first end of the seal expansion member 12 could be connected to the bracket 11 through a bearing or some form of rotatable joint

S allowing the seal expansion member 12 to be swung out in a substantial horizontal plane until the second end of the seal expansion member 12 would press the flexible sealing member 8 against the inside wall 24 of the wind turbine tower part 7. Or in another embodiment the seal expansion members 12 could also or instead comprise some sort of jacking mechanism, springs, a scissor mechanism or other.

In all the embodiment discussed in the above the seal expansion members 12 are displaceably connected to the bracket 11 or brackets 11 so that the seal expansion members 12 can be displaced in a plane substantially parallel to a top surface 14 of the platform 6. However, in another embodiment the seal expansion members 12 18 could be arranged to be swung out in a predominantly vertical direction or the seal expansion members 12 could be arranged displaceably in numerous other ways.

In this embodiment the flexible sealing member 8 comprises an upper side 21 and a lower side 22 and in this embodiment the seal expansion members 12 are arranged at the lower side 22 of flexible sealing member 8 so that the seal expansion members 12 are extending below flexible sealing member 8 once the flexible sealing member 8 is expanded.

Fig. 8 illustrates a closeup of a platform 6 with a reversed flexible sealing member 8 — after expansion, as seen from the front.

In this embodiment the flexible sealing member 8 is arranged at the upper side of the flexible sealing member 8 so that the seal expansion members 12 are extending above the flexible sealing member 8 once the flexible sealing member 8 is expanded.

In this embodiment the platform 6 could further comprise plate parts arranged to be

DK 181736 B1 19 placed on top of the trench formed by the flexible sealing member 8 to e.g, prevent personnel from tripping over the seal expansion members 12 or prevent tools or other from falling into the trench formed by the flexible sealing member 8 and potentially damage the flexible sealing member 8.

The invention has been exemplified above with reference to specific examples of flexible sealing members 8, brackets 11, seal expansion members 12 and other.

However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims.

List 1. Wind turbine 2. Tower 18 3. Nacelle 4. Rotor

S. Blade 6. Platform 7. Wind turbine tower part 8 Flexible sealing member 9. First end of flexible sealing member 10. Periphery of platform 11. Bracket 12. Seal expansion member 13. Second end of flexible sealing member 14. Top surface of platform 15. Central part of platform 16. Elongated rod 17. External thread of elongated rod 18. Nut member of bracket

DK 181736 B1 20 19. Internal thread of nut member 20. Clamping plate 21. Upper side of flexible sealing member 22. Lower side of flexible sealing member 23. Connection member 24. Inside wall of wind turbine tower part 25. Flange connection 26. Lower connection flange 27. Upper connection flange 28. Transition piece 29. Monopile 30. Fixing plates

Claims

DK 181736 B1 21 PATENT CLAIM

1. Platform (6) for a wind turbine tower part (7), which platform (6) comprises a flexible sealing element (8), characterized in that a first end (9) of the flexible sealing element (8) is connected to the platform (8) in a periphery (10) of the platform (6), where the platform (8) further comprises at least one bracket (11) connected to the platform (6) in the peripheral (10) of the platform (8), and a number sealing expansion elements (12), where each of the sealing expansion elements (12) is connected to another end (13) of the flexible sealing element (8), and each of the number of sealing expansion elements (12) is slidably connected to a bracket (11) of the least one bracket (11). ice

2. Platform (8) according to claim 1, where the flexible sealing element (8) extends along the entire periphery (10) of the platform (6).

3. Platform (8) according to claim 1 or 2, where the number of sealing expansion elements (12) are displaceably connected to the at least one bracket (11), so that the sealing expansion elements (12) can be displaced | a plane substantially parallel to an upper side (14) of the platform (8).

4. A platform (8) according to any one of the preceding claims, wherein the number of seal expansion members (12) are arranged to expand in a radial direction away from a central part (15) of the platform (8).

5. Platform (6) according to any one of the preceding claims, wherein the number 235 of seal expansion elements (12) are configured to structurally support the platform (8) in a horizontal direction | the wind turbine tail part (7).

6. Platform (8) according to any one of the preceding claims, wherein the number of sealing expansion elements (12) comprises an elongated rod (18) with

DK 181736 B1 22 external thread (17), where the at least one bracket (11) comprises a nut element (18) with internal thread (19), and where the number of sealing expansion elements (12) are displaceably connected to the at least one bracket (11) by means of of engagement between the external thread (17) and the internal thread (19).

p

7. Platform (8) according to any one of the preceding claims, wherein the number of sealing expansion elements (12) are connected to the other end (13) of the flexible sealing element (8) by means of a clamping plate (20).

8. Platform (8) according to any one of the preceding claims, wherein the first end (9) of the flexible sealing element (8) is connected to the platform (6) by means of the at least one bracket (11).

9. Platform (8) according to any one of the preceding claims, wherein the flexible sealing element (8) is made of a polymer material such as neoprene.

10. Method for sealing a platform (6) inside a wind turbine tower part (7), which method comprises the steps of connecting a first end (9) of a flexible sealing element (8) to the olate form (8) in a periphery ( 10) of the platform (8), ® at least one bracket (11) is connected to the platform (6) in the peripheral (10) of the platform (6), e another end (13) of the flexible sealing element (8) is connected to a number of sealing expansion elements (12), ® each of the number of sealing expansion elements (12) is slidably connected to the at least one bracket (11), e the platform (6) is placed inside | a wind turbine tower part (7), and » the number of sealing expansion elements (12) are displaced outwardly relative to the at least one bracket (11) in order to press the other end (13) of the flexible sealing element (8) against an inner wall (24) of the wind turbine tower part (7).