Air-tight platform

Abstract

A platform 100 for providing a watertight seal in an offshore wind turbine tower. The tower includes a foundation pile 300 and transition piece 200. The platform 100 comprises a platform main body 10

Description

FIELD The invention relates to wind turbines and particularly to an air-tight platform solution for the interior of an offshore wind turbine foundation pile or tower. Background In the context of wind turbine systems, particularly offshore systems, the tower of a wind turbine is generally placed on a foundation of support structure (pile) anchored, in the case of an offshore system, for example to the seabed. For offshore wind turbine that are placed in relatively shallow water, the support structure can comprise a foundation pile arranged in the seabed, also referred to as monopile. The foundation may be a Monopile (MP) or Gravity Based System (GBS). But the pile may also be a tripod structure or other suitable support structure. The term monopile will be used below in a generic sense. Other pile structures include any type of jacket foundation, such as a tripod or tetrapod foundation. In order to connect the wind turbine tower to the monopile a transition piece is commonly used. The transition piece is connected at a lower side thereof to the monopile and on an upper side thereof to the wind turbine tower. For example the transition portion may sit on a flange in an upper portion of the monopile and the tower may be seated on a flange on an inner surface of the upper portion of the transition piece. The transition piece can, if desired, be provided with add-on constructions such as a work platform, a jetty and other useful applications. A gondola or nacelle is then placed on top of the wind turbine tower, and a hub mounted on the nacelle is provided with rotor blades. The equipment required for the operation of the wind turbine is generally placed in the nacelle or in the tower. This equipment comprises inter alia electrical equipment, such as transformers, switchgear, converters and the like. When installing, mud and water are trapped in the MP. It is known, therefore, to protect electrical equipment inside the transition piece and / or tower by sealing the upper portion of the MP or at the transition piece to avoid fluids (including gases)' and moisture from penetrating from the MP to the tower via the transition piece. Basically a flange plate sits on an internal flange of an internal surface of the MP or transition piece and is welded to the internal surface of the MP / transition piece. The portion of the tower above the seal is a controlled environment, ventilated, for example, by the turbine. In a known configuration (Figure 1), a flange 1 is provided in the foundation pile 300 by welding a flange 1 and stiffeners 2 to the inside wall of the foundation pile 300 below the foundation pile end flange. A platform 3 is connected to a flange 400 of a transition piece 200 by longitudinal beams 110. The transition piece 200 and platform 3 are lowered into the foundation pile 300 until the transition piece flange sits 400 on the foundation pile end flange 330 and the platform 3 is landed onto the flange 1 welded to the internal wall. This solution requires a lot of welding at the foundation pile wall, which is time consuming and costly. Furthermore, a problem has been discovered in that it is necessary to drive the foundation pile 300 into place using an impact hammer, for example 5500 KJ impact hammer, which may lead to a problem of cracking at the weld formed in the foundation pile during pile driving. As can be seen from Figure 1, the platform hangs from vertical structural beams attached to a flange of the transition piece inner circumferential wall, conveniently a connection or cooperation portion between the monopile and the transition piece. The lower surface of the platform includes a horizontally extending flange that must be welded to the internal circumferential surface of the monopile. The flange is provided with a series of stiffener plates that abut the monopile internal surface and the bottom of the platform flange. The flange and stiffeners must be welded to the monopile internal surface to ensure that the join is air tight. This procedure is timely and costly. European Patent publication EP3438449 discloses a self-supporting support structure for wind turbine equipment, wherein the support structure can be accommodated in a hollow peripheral body comprising a transition piece for connecting a tower of an offshore wind turbine to a foundation pile, or comprising a foundation pile itself, wherein the support structure comprises two or more floors placed vertically above each other and supported by one or more upright supports, at least one floor connects substantially fittingly to an internal peripheral wall of the peripheral body, and said floor is provided with means for reducing its surface area. Specifically, the self-supporting structure includes plural floors and one of the “upper floors” is provided with the means for reducing its surface area and a lower floor is provided along a peripheral edge with sealing means configured to realize a substantially airtight seal with the internal peripheral wall of the peripheral body. EP3438449 relates principally to the upper floor including the means for reducing its area. This floor is explicitly “substantially fitting” with the inner surface of the MP or transition piece. On the other hand, the lower floor is provided with sealing means along its peripheral edge, and is substantially airtight. The described sealing means uses a rubber profile. Specifically, the lower airtight floor is situated at a distance below the mounting means such that after coupling the transition piece to the foundation pile, the airtight floor connects to a stop (presumably a circular flange on the inner circumferential surface) provided on the internal wall of the foundation pile. A rubber sealing ring is held tightly between a lower edge of the lower floor and the stop of the foundation pile or transition piece. Consequently, EP3438449 discloses a lower floor including a sealing ring on a lower flange surface that sits on a cooperating flange of the inner peripheral surface of the foundation pile of transition piece. Presumably the theory is that the weight of the “self-supporting” structure provides the necessary force on the sealing ring to provide a substantially airtight seal. This solution does not provide for a platform below the flange at the foundation pile / transition section interface. On the other hand the upper floor is provided with, for example, foldable edge parts “to enable the support structure to be placed in any peripheral body and to simultaneously realize the fitting connection”. More than one upper floor may be fitted with the surface area reducing means. Since, towers and transition pieces generally have reducing widths or circumferences as height increases, EP3438449 provides the ‘surface area’ reducing means in order to allow the self-supporting structure to be placed in the transition piece. DK 180536 B discloses an off-shore wind turbine sealing system for sealing the inner side of a lower section against an upper section comprising a closing structure placed substantially horizontally inside the support structure. The sealing system comprises a closing structure extending in a radial direction and adapted to be placed substantially horizontally inside the wind turbine support structure. The sealing system is characterised by, a support system arranged to support the closing structure in the inner side of the wind turbine support structure, a sealing element sealingly connected to the closing structure along a closed path, and expansion means adapted to move a contact part of the sealing element in the radial direction from a retracted position to an extended position along a second closed path to abut against an inner wall. That is the retracted part moves laterally from the retracted position to the extended position. The prior art requires modification of the foundation pile member or the transition piece to provide a suitable flange for resting a seal member, or requires a complex mechanical arrangement for expanding the sealing member. A simpler and cheaper solution is desirably. SUMMARY An aspect of the invention provides a platform for providing a water tight seal in an offshore wind turbine tower including a foundation pile and a transition piece, the platform comprising, a platform main body providing a platform surface having a periphery, at least one flap surrounding the main body and pivotally connected to the main body, a seal member providing a peripheral portion surrounding the periphery of the main body and attached to the or each flap. The at least one flap is configured to be pivoted relative to the platform main body so as to raise the peripheral portion from a transport position where the platform has a first diameter to an installation position where the platform has a second diameter greater than the first diameter. The operation of raising the peripheral portion of the seal member to the installation position may provide an airtight seal or allow an airtight seal to be made between the platform and the foundation pile wall. The platform may have a plurality of flaps spaced around the periphery of the platform main body. The seal member may be attached to the platform main body and the flaps are connected to the main body by the seal member. The platform main body may overlaps an edge of the or each flap. The seal member may include a profiled head around the peripheral circumferential portion thereof. The seal member includes one or more elastomeric materials and wherein a hardness of the seal member at a circumferential peripheral portion therefor is lower than a hardness of a main body portion of the seal member. The, or each, flap may carry at least one bracket or eye plate on an upper surface thereof. The platform may include a plurality of turnbuckles connecting the or each flap to the platform for securing the or each flap in the transport position and / or the installation position. The invention provides in another aspect, a transition piece for an off shore wind turbine having a flange, and comprising the platform in accordance with the invention attached to the flange. The invention provides in a further aspect, a method of installing the platform of the invention, the method comprising: lowering the platform into a foundation pile past a flange of the foundation pile with the or each flap and seal member in the transport position; when the platform is in position, winching the or each flap to the installation position, whereby the peripheral portion of the seal member abuts sealingly against an inner wall of the foundation pile. The method may comprise securing the flaps in the installation process using turnbuckles connected between the flaps and the main body of the platform. The method may comprise connecting the platform to a flange of a transition piece by a plurality of beams, and wherein lowering of the platform includes lowering the platform and transition piece so that a flange of the transition piece cooperates with the flange of the foundation pile and the platform is suspended within the foundation pile. BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a cut away view of a portion of a monopile and transition piece with a air tight seal system according to a prior art solution; Figure 2 is a cut away view of an installed airtight platform system according to an embodiment or the invention; Figure 3 is a cut away view of an airtight platform system in an uninstalled configuration according to an embodiment; Figures 4a and 4b are cross sectional view of a portion of the seal system before installation, according to an embodiment Figure 5a and 5b are further cross-sectional view of the portion of the seal system during installation; Figure 6a and 6b are further cross-section view of the portion of the seal system in an installed configuration; Figures 7 a and 7b are cross-sectional views of the portion of the seal system in more detail; Figure 8 is a perspective view of the seal system of the invention in an installed configuration according to an embodiment; Figure 9 is a perspective view of a portion of the seal system of the invention in an installed configuration in more detail according to an embodiment; DESCRIPTION OF EMBODIMENTS The present disclosure provides a novel sealing method for an air-tight platform for a wind turbine assembly. The invention relates to an air-tight seal solution for an air-tight platform for sealing the inside of a foundation or pile structure of a wind turbine tower, particularly for an offshore wind turbine system. At a high level, the proposal for an air-tight platform, provides a platform that does not require a ring flange, stiffeners or the use of welding to the foundation pile or transition piece. Instead, a platform for sealing the foundation pile is provided with a rubber seal member attached to moveable peripheral flaps surrounding the circumference of the platform. Specifically the circumferential flaps are configured to move in a pivoting motion relative to a major plane of the platform. Figure 2 shows a cut-away perspective view of a platform 100 of the invention installed to provide a water tight seal solution in a wind turbine tower. Figure 2 shows a transition piece 200 on a foundation pile 300 and a flange 400 of the transition piece 200 from which the platform is suspended. The flange 400 cooperates with a flange 330 of the foundation pile in a known manner. The solution does not require modification of the known monopile / transition piece structure. The fixed flange plate and stiffeners of the known platform of figure 1, are replaced with a seal member 20 carried by a plurality of moveable flaps as described below. The platform of the invention may be installed first on the transition piece 200. The longitudinal beams 110 are connected to the flange 400 at one end and are connected to the platform 100 at their other ends. Openings for pipes and cables are not shown in the drawings but these will generally be formed before installation the necessary cables being inserted through the platform and the openings sealed to maintain the integrity of the airtight platform. The air-tight platform 100 of the disclosure comprises central main body 10, and a seal member 20 providing a continuous, 360 degree, rubber seal around the circumference of the main body 10. The main body 10 of the platform itself may be suspended from the flange 400 of the transition piece 200 as described above. The seal member 20 is provided with a series of circumferential flaps 30 which in use can be arranged horizontally in substantially the same plane as the bottom surface 11 of the platform main body 10. The seal member 20 is attached to the main body 10 and the circumferential flaps 30. That is, the seal member 20 and the main body are attached to each other and the flaps 30 and seal member 20 are also attached to each other. As described below flaps 30 may be pivotally connected to the main body 10 by hinges on each flap to preserve the stiffness and integrity of the seal. The flaps 30 carry the seal member 20 which is connected to the main body 10 and to the flaps 30. The number of flaps 30 is not fixed. An embodiment is envisaged where there is a single ring shaped flap 30. In an embodiment there are at least 4 flaps 30. The preferred number of flaps may depend on the size of the platform. The flaps 30 may be generally evenly spaced around the main body 10 on the seal member. There may be, but does not need to be a gap between the main body 10 and the flaps 30. In an embodiment the periphery of the main body 10 may overlap the flaps 30 (see figures 4 to 7). The flaps 30 are generally planar and should have enough strength and stiffness to withstand the forces involved in the installation process (see below). The flaps 30 may be made out of steel for instance. As shown best in Figure 9, in an embodiment, the flaps 30 are arranged as a split ring with the width of the spaces increasing towards the outer perimeter of the seal member 20 when the seal member 20 is in the installed position with the flaps 30 horizontal. The seal member 20 may be made of any material that will provide a good seal or may be made of a composite material with the peripheral edge sealing portion made out of a material for forming a good seal with the foundation pile internal wall. Conveniently a rubber material or rubber like material can be used. The term “rubber” is being used in a generic sense and the material does not necessarily have to be made of rubber, but a rubber or other elastomeric material is suitable. The rubber seal member 20 may be a sheet member onto which the bottom surface 11 of the main body 10 is attached, for example using an adhesive or by any convenient means (e.g. stapling or a combination of a bracket and a fixing such as bolt or nail). In an embodiment the flaps are connected to the platform by hinges, for example a pair of hinges for each flap. In embodiments including the hinges the flaps 30 move pivotally around the hinges and the gaps between the flaps 30 allow the flaps 30 to be pivoted downwards. The sheet of the seal member 20 may therefore have a larger surface area than the main body 10 which can be located centrally on the sheet The perimeter of the sheet extending beyond the main body 10 will then form the portion of the seal member 20 (circumferential peripheral portion 22) that provides the seal against the inner peripheral wall of the foundation pile 300. The upper surface of the perimeter portion 22 of the seal member carries the plurality of flaps 30. In other words, in an embodiment, the flaps 30 are attached to the upper surface of the peripheral portion 22 of the seal member 20 that surrounds the platform main body 10. This is only an example, and the flaps 30 may be provided on the bottom surface of the seal member 20 or enclosed within a periphery of the seal member 20, for example. In an alternative embodiment, the seal member 20 may be a ring shaped member having an internal diameter smaller than the diameter of the main body and an outer diameter greater than the diameter of the main body. The ring shaped member still provides the circumferential peripheral portion 22 but has an inner peripheral portion attached to the outer periphery of the bottom surface 11 of the main body 10. As shown in Figure 2 or 3 the main body 10 of the platform 100 may have a sandwich structure as is known and may have an external circumferential wall 12 covering the sandwich structure. The external circumference (diameter) of the platform 10 must be smaller than the internal circumference (diameter) of the monopile at the flange 400 provided at the junction of the foundation pile 300 and the transition piece 200. The diameter of the inner circumference of the flange 400 is narrower than the diameter of the transition piece 200 above the flange 400. Furthermore, the diameter of the monopile 300 will normally increases below the transition piece 200. Consequently, as shown in figure 3, it is proposed to insert the platform 10 into the foundation pile 300 with the flaps 30 in a vertical position, or even folded under the main body 10 of the platform 100. With the flaps 30 vertical, the circumferential peripheral portion 22 describes an external cylindrical surface substantially corresponding to that of the sidewalls of the main body 10, as shown in figure 3. During transport and installation the flaps may be tied back or otherwise kept in place since the seal member, that is the peripheral portion 22, may be naturally biased outwards. The flaps 30 include one or more eye plates 32 (or other suitable bracket) for attachment of a wire or cable (not shown). Since the flaps 30 carrying the rubber seal may be biased upwards (outwards) in the absence of some restraint, during transport and before installing, the flaps 30 can secured in a folded inward positon by strapping or wiring the flaps to each other as shown in Figure 3. By this means the peripheral portion 22 may be secured inwards of the external circumference of the platform main body 10 so as to be out of the way during transportation and insertion procedures. Figures 4, 5 and 6 compare three conditions of the seal member 20. Each figure shows a simplified cross section through the outer periphery of the main body 10 and the peripheral portion 22 of the seal member 20. Figures 4a, 5a, and 6a, are cross-section through a part of the seal member 20 including a flap 30, whereas figures 4a, 5a and 5b are cross-section thought the seal member 20 between two flaps 30. In figures 4a and 4b, the flap 30 is shown in the transport or installation position with the flap 30 normal to the plane of the platform main body 10. This embodiment includes a ring shaped seal member 20 which is fixed to the main body 10 using a fixing element 24 and to the flap by fixing element 26. The upper portion of figure 4 shows a simplified cross section of the platform with the seal member folded inwards for transport. In the transport condition, the flaps 30 may be connected to each other by ties (not shown) which prevent the flaps 30 and therefore the peripheral portion 22 from moving upward and outward. In Figures 5a and 5b the seal member 20 is being prepared for installation or release position. The ties (not shown) retaining the flaps 30 in the lowered or vertical position have been released and peripheral portion 22 of the seal member 20 is free to straighten causing the flaps 30 to rise and move outward. The degree of movement at this point is dependent on the biasing caused by the seal member. The degree of movement is not important and can vary from no movement of the flaps 30 to full elevation of the flaps 30 until movement is prevented by, for example the side wall of the foundation pile 30. In any case, in this configuration the flaps 30 are free to move. Depending on the degree of bias, if sufficient, the flaps 30 will swing out until they reach the internal wall of the foundation pile. Finally, figures 6a and 6b show an operating or installed position, in which the flaps 30 have been pulled up substantially to be horizontal and in the same plane (or a parallel plane) as the bottom surface of the platform main body 10. Figure 7 shows the installed position in more detail. The peripheral portion 22 has a profiled head 23 at the periphery thereof to increase stiffness and ensure a good seal is provided against the inner periphery of the foundation pile 300. As shown in Figure 7, as the flap reaches the horizontal, (or as near as horizontal as can be achieved) the seal member circumferential portion 22 is trapped by the inner peripheral wall of the foundation pile 300. The profiled head 23 which may be 20% to 100% thicker than the seal member 20 has a decreasing width with increasing height. The profiled head 23 may be conic or pyramidal for instance. The narrow nose of the profiled head 23 is forced flush against the inner peripheral wall of the foundation pile to effect the seal. Figure 7a also shows a metal bar or ring 25 used to securely fix the seal member 20 to the flap 30. Similarly, Figure 7b shows a metal bar or ring 27 used to affix the seal member 20 to the platform main body 10. Whilst in the exemplified embodiments, the sealing member is pivoted from a transport position ‘below’ the platform and raised to the installation position, for example, by winching, it will be understood that the sealing member might be arranged to move pivotally relative to an upper surface of the platform main body and that the sealing member may be folded ‘upwards’ in the transport position, for example, either vertically or to lay flat on the top surface of the platform (or anywhere in between). In these embodiments, the sealing member would then be pivoted in the opposite direction (‘downwardly’) to the installation position. As shown in Figures 8 and 9, the flaps 30 each have at least one eye plate 32 or other attachment means. In this embodiment there are three eye plates on each flap 30. A winch can be attached to one of the eye plates 32 (for example a middle eye plate). The winch (not shown), which may be secured for example to any suitable fixed point, is used to pull the flaps up and to provide sufficient force that the seal between the head 23 and the wall of the foundation pile is water tight. Any gaps can be sealed by any appropriate sealant. The flaps 30 are locked into position by turnbuckles 34, which can be individually tightened. The turnbuckles 34 can also be used during transport to ensure that the flaps 30 do not move from their transport position by lengthening the turnbuckles 34. In this case, jaw ended turnbuckles are used to allow the flaps 30 and peripheral portion 22 of the seal member 20 to pivot. Various jacking systems can be used to lift the flaps of the seal member 20 up to the operating position with a force of a few hundred pounds. The jacking systems may be installed on the platform 10 or tower structure and this will be used to ensure that the seal is fully deployed. An electric, portable winch, which may be battery powered can be used instead or in addition to increase the tightness of the seal. The seal material, may be an elastomeric material and may be a composite. Natural rubbers may be used and more than one rubber material may be used. One example would be a composite material including a hard compound, for example approximately 62 shore A hardness, such as NR 16-3209 or similar, used as the seal member 20 main body or inner circumferential portion thereof. This material provides a higher stiffness and therefore more reaction force and sealing capacity as the seal is pressed to the monopile wall. In addition, the circumferential peripheral portion or at least the portion thereof constituting the profiled head 23 may include a soft compound of approximately 43 shore A hardness, such as NR 14-1753 may be used for the nose of the seal, which results in a lower local stiffness such that the nose of better capable of fitting potential irregularities in the contact surface of the monopile wall or sealing surface. The filling capacity is especially important when sealing off small cavities or crevices at a low differential pressures. 5 If a seal is not properly tightened towards the MP wall - a later maintenance operation can close the gap by a further winching operation and / or using a sealant that can be poured into position. 10 It is proposed that the airtight platform seal will be designed for a pressure of 0.1 Bar, but since there is ventilation above and below the platform, the difference in pressure will generally be zero in use.

Claims

1. A platform for providing a water tight seal in an offshore wind turbine tower including a foundation pile and a transition piece, the platform comprising:a platform main body providing a platform surface having a periphery,at least one flap surrounding the main body and pivotally connected to the main body;a seal member providing a peripheral portion surrounding the periphery of the main body and attached to the or each flap;wherein the at least one flap is configured to be pivoted relative to the platform main body so as to move the peripheral portion from a transport position where the platform has a first diameter to an installation position where the platform has a second diameter greater than the first diameter.

2. The platform of claim 1 comprising a plurality of flaps spaced around the periphery of the platform main body.

3. The platform of claim 1 or 2, wherein the seal member is attached to the platform main body and the flaps are connected to the main body by the seal member.

4. The platform of claim 1, 2 or 3, wherein the platform main body overlaps an edge of the or each flap.

5. The platform of any one of claims 1 to 4, wherein the seal member includes a profiled head around the peripheral circumferential portion thereof.

6. The platform of any one of claims 1 to 5, wherein the seal member includes one or more elastomeric materials and wherein a hardness of the seal member at a circumferential peripheral portion therefor is lower than a hardness of a main body portion of the seal member.

7. The platform of any one of claims 1 to 6, wherein the or each flap carries at least one bracket or eye plate on an upper surface thereof.

8. The platform of any one of claim 1 to 7, comprising a plurality of turnbuckles connecting the or each flap to the platform for securing the or each flap in the transport position and / or the installation position.

9. The platform of any one of claims 1 to 8, wherein the at least one flap is configured to be pivoted relative to the platform main body so as to raise the peripheral portion from the transport position to the installation position.

10. A transition piece for an off shore wind turbine comprising a flange, and a platform according to any one of claims 1 to 9 attached to the flange.

11. A method of installing the platform of any one of claims 1 to 8, the method comprising:lowering the platform into a foundation pile past a flange of the foundation pile with the or each flap and seal member in the transport position;when the platform is in position, moving the or each flap from the transport position to the installation position, whereby the peripheral portion of the seal member abuts sealingly against an inner wall of the foundation pile in the installation position.

12. The method of claim 11, wherein the step of moving the or each flap comprises winching the or each flap to the installation position.

13. The method of claim 11 or 12, further comprising securing the flaps in the installation process using turnbuckles connected between the flaps and the main body of the platform.

14. The method of claim 11, 12 or 13, comprising connecting the platform to a flange of a transition piece by a plurality of beams, and wherein lowering of the platform includes lowering the platform and transition piece so that a flange of the transition piece cooperates with the flange of the foundation pile and the platform is suspended within the foundation pile.Amendments to the claims have been filled as follows:14 01 2515CLAIMS:

1. A platform for providing a water tight seal in an offshore wind turbine tower including a foundation pile and a transition piece, the platform comprising:5 a platform main body providing a platform surface having a periphery,at least one flap surrounding the main body and pivotally connected to the main body;a seal member providing a peripheral portion surrounding the periphery of the main body and attached to the or each flap;10 wherein the at least one flap is configured to be pivoted relative to the platformmain body so as to move the peripheral portion from a transport position where the platform has a first diameter to an installation position where the platform has a second diameter greater than the first diameter.15 2. The platform of claim 1 comprising a plurality of flaps spaced around theperiphery of the platform main body.

3. The platform of claim 1 or 2, wherein the seal member is attached to the platform main body and the flaps are connected to the main body by the seal member.

204. The platform of claim 1, 2 or 3, wherein the platform main body overlaps an edge of the or each flap.

5. The platform of any one of claims 1 to 4, wherein the seal member includes a 25 profiled head around the peripheral circumferential portion thereof.

6. The platform of any one of claims 1 to 5, wherein the seal member includes one or more elastomeric materials and wherein a hardness of the seal member at a circumferential peripheral portion therefor is lower than a hardness of a main body30 portion of the seal member.

7. The platform of any one of claims 1 to 6, wherein the or each flap carries at least one bracket or eye plate on an upper surface thereof.

8. The platform of any one of claim 1 to 7, comprising a plurality of turnbuckles connecting the or each flap to the platform for securing the or each flap in the transport position and / or the installation position.

9. The platform of any one of claims 1 to 8, wherein the at least one flap is configured to be pivoted relative to the platform main body so as to raise the peripheral portion from the transport position to the installation position.

10. A transition piece for an off shore wind turbine comprising a flange, and a platform according to any one of claims 1 to 9 attached to the flange.

11. A method of installing the platform of any one of claims 1 to 8, the method comprising:lowering the platform into the foundation pile past a flange of the foundation pile with the or each flap and seal member in the transport position;when the platform is in position, moving the or each flap from the transport position to the installation position, whereby the peripheral portion of the seal member abuts sealingly against an inner wall of the foundation pile in the installation position.

12. The method of claim 11, wherein the step of moving the or each flap comprises winching the or each flap to the installation position.

13. The method of claim 11 or 12, further comprising securing the flaps in the installation process using turnbuckles connected between the flaps and the main body of the platform.

14. The method of claim 11, 12 or 13, comprising connecting the platform to a flange of the transition piece by a plurality of beams, and wherein lowering of the platform includes lowering the platform and transition piece so that the flange of the transition piece cooperates with the flange of the foundation pile and the platform is suspended within the foundation pile.

Images