WO2018065021A1 - An access arrangement for use with an offshore support structure for a wind turbine - Google Patents

An access arrangement for use with an offshore support structure for a wind turbine Download PDF

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Publication number
WO2018065021A1
WO2018065021A1 PCT/DK2017/050329 DK2017050329W WO2018065021A1 WO 2018065021 A1 WO2018065021 A1 WO 2018065021A1 DK 2017050329 W DK2017050329 W DK 2017050329W WO 2018065021 A1 WO2018065021 A1 WO 2018065021A1
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WO
WIPO (PCT)
Prior art keywords
transfer
access arrangement
transfer platform
support structure
platform
Prior art date
Application number
PCT/DK2017/050329
Other languages
French (fr)
Inventor
John Friis LØNDAL
Original Assignee
Mhi Vestas Offshore Wind A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mhi Vestas Offshore Wind A/S filed Critical Mhi Vestas Offshore Wind A/S
Publication of WO2018065021A1 publication Critical patent/WO2018065021A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B27/00—Arrangement of ship-based loading or unloading equipment for cargo or passengers
    • B63B27/14—Arrangement of ship-based loading or unloading equipment for cargo or passengers of ramps, gangways or outboard ladders ; Pilot lifts
    • B63B27/146—Pilot ladders or similar outboard ladders, e.g. bathing ladders; Pilot lifts
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/0034—Maintenance, repair or inspection of offshore constructions
    • E—FIXED CONSTRUCTIONS
    • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
    • E06C—LADDERS
    • E06C7/00—Component parts, supporting parts, or accessories
    • E06C7/16—Platforms on, or for use on, ladders, e.g. liftable or lowerable platforms
    • E—FIXED CONSTRUCTIONS
    • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
    • E06C—LADDERS
    • E06C9/00—Ladders characterised by being permanently attached to fixed structures, e.g. fire escapes
    • E06C9/02—Ladders characterised by being permanently attached to fixed structures, e.g. fire escapes rigidly mounted
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D13/00—Assembly, mounting or commissioning of wind motors; Arrangements specially adapted for transporting wind motor components
    • F03D13/20—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
    • F03D13/25—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors specially adapted for offshore installation
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0091—Offshore structures for wind turbines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2230/00—Manufacture
    • F05B2230/60—Assembly methods
    • F05B2230/61—Assembly methods using auxiliary equipment for lifting or holding
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/727—Offshore wind turbines
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to an access arrangement allowing personnel to access an offshore wind turbine in a safe manner.
  • the personnel From time to time it is necessary that personnel access a wind turbine, e.g. for maintenance or inspection purposes.
  • the wind turbine is an offshore wind turbine
  • the personnel must either access the wind turbine from a helicopter or from a sea vessel.
  • the helicopter could land on a landing platform, or the personnel could be hoisted from the helicopter to a platform on top of the wind turbine.
  • the personnel will normally enter the nacelle of the wind turbine via a hatch or the like in the nacelle.
  • the sea vessel will normally be moored to the support structure of the wind turbine, and the personnel must transfer from the sea vessel to an access arrangement on the support structure of the wind turbine.
  • the personnel have performed the required tasks at the wind turbine, they must transfer back to the sea vessel via the access arrangement.
  • the sea vessel Since the sea vessel is floating at sea, it is subjected to heave, yaw and rolling motions, due to waves, and it is thereby non-stationary with respect to the seabed.
  • the off shore support structure On the other hand, the off shore support structure is stationary with respect to the seabed. Accordingly, the personnel need to transfer between a non-stationary sea vessel and a stationary offshore support structure. This may require the personnel to jump from the sea vessel onto a ladder mounted to the offshore support structure or vice versa, e.g. at a time where the sea vessel is closest to a given part of the ladder. This introduces safety issues, in particular when the personnel are returning to the sea vessel, because during this transfer they will normally be positioned with their back towards the sea vessel due to the position of the ladder. This makes it difficult for the personnel to orient themselves relative to the sea vessel, and the jump from the offshore support structure to the sea vessel must be performed in a backwards direction. DESCRIPTION OF THE INVENTION
  • the invention provides an access arrangement for use with an offshore support structure for a wind turbine, the access arrangement comprising :
  • the first aspect of the invention relates to an access arrangement.
  • the term 'access arrangement' should be interpreted to mean an arrangement which allows a person to access a structure having the access arrangement mounted thereon, or to a structure being arranged in the immediate vicinity of the structure having the access arrangement mounted thereon. Since the access arrangement according to the first aspect of the invention is for use with an offshore support structure for a wind turbine, the access arrangement allows access to the offshore support structure and/or to the wind turbine.
  • the support structure could be or form part of a foundation for an offshore wind turbine. This will be described in further detail below.
  • the access arrangement comprises a ladder with a plurality of steps.
  • the steps are arranged with mutual distance along a longitudinal axis defined by the ladder. Accordingly, a person using the access arrangement for accessing the support structure and/or the wind turbine can climb or descend the ladder, via the steps.
  • the steps are attached to the offshore support structure.
  • the steps could be directly attached to the offshore support structure, e.g. by means of welding or using attachment means, such as screws, bolts or the like.
  • the steps could be mounted on or be integrally formed with a set of longitudinal ladder elements, which are in turn attached to the support structure.
  • the steps are permanently mounted on the support structure, directly or indirectly, and will normally not be removed when the access arrangement is not in use.
  • the access arrangement further comprises at least one transfer platform adapted to carry a person.
  • 'transfer platform' should be interpreted to mean a platform which can be used during transfer of a person from/to a vessel to/from the access arrangement.
  • each transfer platform is adapted to carry a person, a person may stand on the transfer platform during a transfer.
  • the person can jump to or from the transfer platform, instead of jumping to or from one of the steps of the ladder.
  • the transfer platform provides a larger area for accommodating a person than a step of a ladder, and therefore the safety during the transfer is improved.
  • the transfer platform allows the person to position himself or herself in such a manner that he or she faces the sea vessel. This makes the person capable of selecting an optimal time for stepping or jumping onto the sea vessel, and the jump can be made with the person in a forwards direction facing the vessel. This in particular improves the safety.
  • the at least one transfer platform may be movable between a transfer position in which the transfer platform can carry a person, and a storage position in which the transfer platform is protected from an ambient environment.
  • the transfer platform can be made available when a transfer is about to be performed, simply by moving the transfer platform to the transfer position, if it is not already positioned in the transfer position.
  • the transfer platform can be positioned in the storage position, where it is protected from the ambient environment. Thereby the risk of damage to the transfer platform is minimised.
  • protected from an ambient environment means that in the storage position the transfer platform is protected from collisions with a sea vessel being moored to the offshore support structure.
  • the storage position could be a position in which the transfer platform is shielded from environmental impacts, e.g. in the form of waves, wind,
  • the at least one transfer platform may be movable between the transfer position and the storage position by pivoting said at least one transfer platform about a substantially vertical axis. According to this embodiment, the transfer platform is rotated in a substantially horizontal plane when being moved between the transfer position and the storage position.
  • the at least one transfer platform may be movable between the transfer position and the storage position by pivoting said at least one transfer platform about a substantially horizontal axis. According to this embodiment, the transfer platform is rotated in a substantially vertical plane when being moved between the transfer position and the storage position.
  • the at least one transfer platform may be movable between the transfer position and the storage position by pivoting said at least one transfer platform about a substantially horizontal axis followed by pivoting said at least one transfer platform about a substantially vertical axis allowing the transfer platform to be stored in a more protected position for example at least partially behind the steps in the storage position.
  • the transfer platform may be moved between the transfer position and the storage position in any other suitable manner, e.g. by means of a translational movement.
  • the at least one transfer platform may comprise locking means arranged to releasably lock the transfer platform in the transfer position and/or in the storage position.
  • the locking means ensure that the transfer platform remains in the transfer position and/or in the storage position until the locking means is actively released.
  • the transfer platform is prevented from accidentally moving between the transfer position and the storage position.
  • the locking means could, e.g., include mating parts arranged to be moved into engagement in order to lock the transfer platform in a given position, and arranged to be moved out of engagement in order to release the transfer platform, and allow the transfer platform to move between the transfer position and the storage position.
  • the transfer platform when the at least one transfer platform is in the storage position, the transfer platform may be arranged substantially within a volume defined by the steps of the ladder and a surface of the offshore support structure, and when the at least one transfer platform is in the transfer position, the transfer platform may protrude from said volume.
  • the steps and the surface of the offshore support structure provide the required protection for the transfer platform when the transfer platform is in the storage position.
  • the transfer platform when the transfer platform is in the transfer position, it protrudes from the volume defined by the steps and the surface of the offshore support structure, and thereby the transfer platform is readily accessible for a person, without risking collision with the steps.
  • the access arrangement may comprise a plurality of transfer platforms arranged with mutual distance along the longitudinal axis defined by the ladder.
  • the exact position of the sea level relative to the offshore support structure changes as a result of tidal effects and waves. It is therefore an advantage to provide the access arrangement with two or more transfer platforms arranged at different positions along the ladder, and thereby along the offshore support structure, because thereby it should be possible to select a transfer platform which is close to the sea level at a given point in time.
  • the offshore support structure may comprise a monopile.
  • other kinds of offshore support structures could be used, which provides an interface between the sea bed and/or an offshore foundation and a wind turbine tower.
  • the invention provides a monopile for an offshore wind turbine tower foundation, the monopile having an access arrangement according to the first aspect of the invention mounted thereon. Accordingly, access to the offshore wind turbine is provided by means of the access arrangement which has been described above.
  • the invention provides a method of accessing an offshore wind turbine tower mounted on an offshore support structure having an access arrangement according to the first aspect of the invention mounted thereon, the method comprising the steps of:
  • FIG. 1 illustrates an access arrangement according to a first embodiment of the invention mounted on an offshore support structure for a wind turbine tower
  • Fig. 2 is a perspective view of the access arrangement of Fig. 1,
  • Fig. 3 shows a front view and a side view of the access arrangement of Fig. 1,
  • Fig. 4 shows a transfer platform for the access arrangement of Fig. 1,
  • FIG. 5 illustrates an access arrangement according to a second embodiment of the invention mounted on an offshore support structure for a wind turbine tower
  • Fig. 6 is a perspective view of the access arrangement of Fig. 5
  • Fig. 7 shows a transfer platform for the access arrangement of Fig. 5 in a storage position
  • Fig. 8 shows the transfer platform of Fig. 7 in a transfer position
  • Fig. 9 illustrates use of the access arrangement of Fig. 5.
  • Fig. 1 illustrates an access arrangement 1 according to a first embodiment of the invention, mounted on an offshore support structure, in the form of a monopile 2, for a wind turbine tower 3.
  • the left part of Fig. 1 shows a perspective view of the monopile 2 and access arrangement 1, and the right part of Fig. 1 shows part of a cross sectional view of the monopile 2 and access arrangement 1.
  • the access arrangement 1 is provided with a number of steps 4, forming a ladder.
  • the steps 4 are arranged with mutual distance along a longitudinal axis defined by the ladder.
  • the access arrangement 1 is further provided with a number of transfer platforms 5, also arranged with mutual distance along the longitudinal axis defined by the ladder.
  • the transfer platforms 5 are adapted to carry a person during transfer between a sea vessel and the access arrangement 1. Accordingly, the person is allowed to jump from the sea vessel to one of the transfer platforms 5 during transfer from the sea vessel to the access arrangement 1, and to jump from one of the transfer platforms 5 to the sea vessel during transfer from the access arrangement 1 to the sea vessel. This considerably increases the safety during transfer, because a larger area is available for accommodating the person. Furthermore, during transfer from the access arrangement 1 to the sea vessel, the person can be oriented in such a manner that he or she faces the sea vessel during the transfer.
  • a transfer platform 5 can be selected which is close to the sea vessel, regardless of various conditions, such as tide or waves.
  • Fig. 2 is a perspective view of the access arrangement 1 of Fig. 1. All of the transfer platforms 5 are in a transfer position, in which the transfer platforms 5 are clear of the steps 4, thereby allowing them to carry a person. However, each of the transfer platforms 5 may be movable between the transfer position shown in Fig. 2 and a storage position in which the transfer platforms 5 are protected from the ambient environment. The storage position for a given transfer platform 5 could advantageously be between two of the steps 4. In this case the transfer platform 5 could be moved from the transfer position to the storage position by pivoting the transfer platform 5 about a substantially vertical axis, swinging the transfer platform 5 towards the steps 4 and into the storage position between the steps 4, where it is protected by the steps 4.
  • Fig. 3 shows a front view and a side view of the access arrangement 1 of Fig. 1.
  • Fig. 4 is a perspective view of a transfer platform 5 for the access arrangement 1 of Fig. 1.
  • the transfer platform 5 is pivotable about a substantially vertical axis 6, thereby allowing the transfer platform 5 to move between the transfer position and the storage position, as described above with reference to Fig. 2.
  • Fig. 5 illustrates an access arrangement 1 according to a second embodiment of the invention mounted on an offshore support structure, in the form of a monopile 2, for a wind turbine tower.
  • the access arrangement 1 of Fig. 5 is provided with a plurality of steps 4, forming a ladder, and the steps 4 are arranged with mutual distance along a longitudinal axis defined by the ladder. Furthermore, the access arrangement 1 is provided with a number of transfer platforms 5 arranged with mutual distance along the longitudinal axis defined by the ladder. The transfer platforms 5 are arranged for carrying a person during transfer between a sea vessel 7 and the access arrangement 1, as described above with reference to Fig. 1, thereby increasing the safety during such transfer.
  • the transfer platforms 5 have a design which differs from the design of the transfer platforms 5 of the access arrangement 1 of Figs. 1-4. This will be described in further detail below.
  • Fig. 6 is a perspective view of the access arrangement 1 of Fig. 5.
  • Two transfer platforms 5 are shown in Fig. 6.
  • One of the transfer platforms 5a is in a transfer position in which it can carry a person during transfer between a sea vessel and the access arrangement 1, i.e. the transfer platform 5a defines a substantially horizontal surface on which a person can stand during the transfer.
  • the other transfer platform 5b is in a storage position, in which the transfer platform 5b is positioned with the surface against an offshore support structure having the access arrangement 1 mounted thereon. Thereby the transfer platform 5b is protected from the ambient environment. In particular, the transfer platform 5b is protected from collisions with a sea vessel being moored to the offshore support structure.
  • Each of the transfer platforms 5 is movable between the transfer position and the storage position by rotating the transfer platform 5 about a substantially horizontal axis 8.
  • the transfer platforms 5 can be locked in the storage position by means of a locking means 9 comprising a tap 10 formed on the transfer platform 5 and a gripping mechanism 11 mounted on the ladder, configured to releasably fix the tap 10. Thereby the transfer platform 5 is prevented from accidentally moving from the storage position to the transfer position. When the transfer platform 5 is in the transfer position, it is prevented from accidentally moving to the storage position, due to gravity.
  • a locking means 9 comprising a tap 10 formed on the transfer platform 5 and a gripping mechanism 11 mounted on the ladder, configured to releasably fix the tap 10.
  • Fig. 7 shows a transfer platform 5 for the access arrangement 1 of Fig. 5 in a storage position. It can be seen that the locking means 9 is in a locked position where the gripping mechanism 11 fixes the tap 10 formed on the transfer platform 5.
  • Fig. 8 shows the transfer platform 5 of Fig. 7 in a transfer position. It can be seen that the tap 10 has been brought out of engagement with the gripping mechanism 11, thereby allowing the transfer platform 5 to rotate to the transfer position, allowing the transfer platform 5 to carry a person.
  • Fig. 9 illustrates use of the access arrangement 1 of Fig. 5. The transfer platform 5a which is closest to the sea vessel 7 is in the transfer position, and a person 12 is standing on the transfer platform 5a. Two other transfer platforms 5b are positioned in the storage position.
  • Fig. 9 the person 12 can easily transfer between the sea vessel 7 and the access arrangement 1, via the transfer platform 5a. It is also clear that the transfer platform 5a defines a surface area which is sufficiently large to allow the person 12 to face the sea vessel 7 during transfer from the access arrangement 1 to the sea vessel 7.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Ocean & Marine Engineering (AREA)
  • Wind Motors (AREA)

Abstract

An access arrangement (1) for use with an offshore support structure (2) for a wind turbine is disclosed. The access arrangement (1) comprises a ladder with a plurality of steps (4) arranged with mutual distance along a longitudinal axis defined by the ladder, the steps (4) being attached to the offshore support structure(2), and at least one transfer platform (5) adapted to carry a person. The transfer platform (5) provides an increased area for accommodating personnel during a transfer and allows personnel to face a sea vessel (7) during transfer from the access arrangement (1) to the sea vessel (7). Thereby safety is improved.

Description

AN ACCESS ARRANGEMENT FOR USE WITH AN OFFSHORE SUPPORT STRUCTURE FOR A WIND TURBINE
FIELD OF THE INVENTION
The present invention relates to an access arrangement allowing personnel to access an offshore wind turbine in a safe manner.
BACKGROUND OF THE INVENTION
From time to time it is necessary that personnel access a wind turbine, e.g. for maintenance or inspection purposes. In the case that the wind turbine is an offshore wind turbine, the personnel must either access the wind turbine from a helicopter or from a sea vessel. In the case that the personnel access the wind turbine from a helicopter, the helicopter could land on a landing platform, or the personnel could be hoisted from the helicopter to a platform on top of the wind turbine. In either case, the personnel will normally enter the nacelle of the wind turbine via a hatch or the like in the nacelle. In the case that the personnel access the wind turbine from a sea vessel, the sea vessel will normally be moored to the support structure of the wind turbine, and the personnel must transfer from the sea vessel to an access arrangement on the support structure of the wind turbine. Similarly, when the personnel have performed the required tasks at the wind turbine, they must transfer back to the sea vessel via the access arrangement.
Since the sea vessel is floating at sea, it is subjected to heave, yaw and rolling motions, due to waves, and it is thereby non-stationary with respect to the seabed. On the other hand, the off shore support structure is stationary with respect to the seabed. Accordingly, the personnel need to transfer between a non-stationary sea vessel and a stationary offshore support structure. This may require the personnel to jump from the sea vessel onto a ladder mounted to the offshore support structure or vice versa, e.g. at a time where the sea vessel is closest to a given part of the ladder. This introduces safety issues, in particular when the personnel are returning to the sea vessel, because during this transfer they will normally be positioned with their back towards the sea vessel due to the position of the ladder. This makes it difficult for the personnel to orient themselves relative to the sea vessel, and the jump from the offshore support structure to the sea vessel must be performed in a backwards direction. DESCRIPTION OF THE INVENTION
It is an object of embodiments of the invention to provide an access arrangement for use with an offshore support structure for a wind turbine, which allows the safety to be improved during personnel transfer between a sea vessel and the offshore support structure. It is a further object of embodiments of the invention to provide a method for accessing an offshore wind turbine tower, which improves the safety for personnel.
According to a first aspect the invention provides an access arrangement for use with an offshore support structure for a wind turbine, the access arrangement comprising :
- a ladder with a plurality of steps arranged with mutual distance along a longitudinal axis defined by the ladder, the steps being attached to the offshore support structure, and
- at least one transfer platform adapted to carry a person.
The first aspect of the invention relates to an access arrangement. In the present context the term 'access arrangement' should be interpreted to mean an arrangement which allows a person to access a structure having the access arrangement mounted thereon, or to a structure being arranged in the immediate vicinity of the structure having the access arrangement mounted thereon. Since the access arrangement according to the first aspect of the invention is for use with an offshore support structure for a wind turbine, the access arrangement allows access to the offshore support structure and/or to the wind turbine. The support structure could be or form part of a foundation for an offshore wind turbine. This will be described in further detail below.
The access arrangement comprises a ladder with a plurality of steps. The steps are arranged with mutual distance along a longitudinal axis defined by the ladder. Accordingly, a person using the access arrangement for accessing the support structure and/or the wind turbine can climb or descend the ladder, via the steps.
The steps are attached to the offshore support structure. The steps could be directly attached to the offshore support structure, e.g. by means of welding or using attachment means, such as screws, bolts or the like. As an alternative, the steps could be mounted on or be integrally formed with a set of longitudinal ladder elements, which are in turn attached to the support structure. In any event, the steps are permanently mounted on the support structure, directly or indirectly, and will normally not be removed when the access arrangement is not in use.
The access arrangement further comprises at least one transfer platform adapted to carry a person. In the present context the term 'transfer platform' should be interpreted to mean a platform which can be used during transfer of a person from/to a vessel to/from the access arrangement.
Since each transfer platform is adapted to carry a person, a person may stand on the transfer platform during a transfer. In particular, the person can jump to or from the transfer platform, instead of jumping to or from one of the steps of the ladder. The transfer platform provides a larger area for accommodating a person than a step of a ladder, and therefore the safety during the transfer is improved. Furthermore, during transfer from the access arrangement to a sea vessel, the transfer platform allows the person to position himself or herself in such a manner that he or she faces the sea vessel. This makes the person capable of selecting an optimal time for stepping or jumping onto the sea vessel, and the jump can be made with the person in a forwards direction facing the vessel. This in particular improves the safety.
The at least one transfer platform may be movable between a transfer position in which the transfer platform can carry a person, and a storage position in which the transfer platform is protected from an ambient environment. According to this embodiment, the transfer platform can be made available when a transfer is about to be performed, simply by moving the transfer platform to the transfer position, if it is not already positioned in the transfer position. However, when a transfer is not ongoing, the transfer platform can be positioned in the storage position, where it is protected from the ambient environment. Thereby the risk of damage to the transfer platform is minimised. In the context of the present application the term "protected from an ambient environment" means that in the storage position the transfer platform is protected from collisions with a sea vessel being moored to the offshore support structure. Additionally, the storage position could be a position in which the transfer platform is shielded from environmental impacts, e.g. in the form of waves, wind,
precipitation and/or other weather conditions.
In one embodiment, the at least one transfer platform may be movable between the transfer position and the storage position by pivoting said at least one transfer platform about a substantially vertical axis. According to this embodiment, the transfer platform is rotated in a substantially horizontal plane when being moved between the transfer position and the storage position.
In a further embodiment, the at least one transfer platform may be movable between the transfer position and the storage position by pivoting said at least one transfer platform about a substantially horizontal axis. According to this embodiment, the transfer platform is rotated in a substantially vertical plane when being moved between the transfer position and the storage position.
In a further embodiment, the at least one transfer platform may be movable between the transfer position and the storage position by pivoting said at least one transfer platform about a substantially horizontal axis followed by pivoting said at least one transfer platform about a substantially vertical axis allowing the transfer platform to be stored in a more protected position for example at least partially behind the steps in the storage position.
As another alternative, the transfer platform may be moved between the transfer position and the storage position in any other suitable manner, e.g. by means of a translational movement.
The at least one transfer platform may comprise locking means arranged to releasably lock the transfer platform in the transfer position and/or in the storage position. According to this embodiment, the locking means ensure that the transfer platform remains in the transfer position and/or in the storage position until the locking means is actively released.
Accordingly, the transfer platform is prevented from accidentally moving between the transfer position and the storage position.
The locking means could, e.g., include mating parts arranged to be moved into engagement in order to lock the transfer platform in a given position, and arranged to be moved out of engagement in order to release the transfer platform, and allow the transfer platform to move between the transfer position and the storage position.
According to one embodiment, when the at least one transfer platform is in the storage position, the transfer platform may be arranged substantially within a volume defined by the steps of the ladder and a surface of the offshore support structure, and when the at least one transfer platform is in the transfer position, the transfer platform may protrude from said volume. According to this embodiment, the steps and the surface of the offshore support structure provide the required protection for the transfer platform when the transfer platform is in the storage position. However, when the transfer platform is in the transfer position, it protrudes from the volume defined by the steps and the surface of the offshore support structure, and thereby the transfer platform is readily accessible for a person, without risking collision with the steps.
The access arrangement may comprise a plurality of transfer platforms arranged with mutual distance along the longitudinal axis defined by the ladder. The exact position of the sea level relative to the offshore support structure changes as a result of tidal effects and waves. It is therefore an advantage to provide the access arrangement with two or more transfer platforms arranged at different positions along the ladder, and thereby along the offshore support structure, because thereby it should be possible to select a transfer platform which is close to the sea level at a given point in time. The offshore support structure may comprise a monopile. As an alternative, other kinds of offshore support structures could be used, which provides an interface between the sea bed and/or an offshore foundation and a wind turbine tower.
According to a second aspect the invention provides a monopile for an offshore wind turbine tower foundation, the monopile having an access arrangement according to the first aspect of the invention mounted thereon. Accordingly, access to the offshore wind turbine is provided by means of the access arrangement which has been described above.
According to a third aspect the invention provides a method of accessing an offshore wind turbine tower mounted on an offshore support structure having an access arrangement according to the first aspect of the invention mounted thereon, the method comprising the steps of:
- moving a transfer platform from a storage position to a transfer position,
- allowing personnel to access the wind turbine tower and/or to descend from the wind turbine tower, via the transfer platform,
- moving the transfer platform from the transfer position to the storage position. Thus, according to the method according to the third aspect of the invention, access to an offshore wind turbine is provided by means of an access arrangement according to the first aspect of the invention. The remarks set forth above with reference to the first aspect of the invention are therefore equally applicable here. Thus, when a transfer from a sea vessel to the access arrangement or from the access arrangement to a sea vessel is required, a transfer platform is initially moved from a storage position to a transfer position. Thereby it is ensured that the transfer platform is in a position in which it is capable of carrying a person to be transferred. Next, a person performs the required transfer via the transfer platform. As described above, this improves the safety during the transfer.
Finally, the transfer platform is moved from the transfer position to the storage position. Thereby it is ensured that the transfer platform is protected from the ambient environment until a transfer is once again required. BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in further detail with reference to the accompanying drawings in which
Fig. 1 illustrates an access arrangement according to a first embodiment of the invention mounted on an offshore support structure for a wind turbine tower, Fig. 2 is a perspective view of the access arrangement of Fig. 1,
Fig. 3 shows a front view and a side view of the access arrangement of Fig. 1,
Fig. 4 shows a transfer platform for the access arrangement of Fig. 1,
Fig. 5 illustrates an access arrangement according to a second embodiment of the invention mounted on an offshore support structure for a wind turbine tower, Fig. 6 is a perspective view of the access arrangement of Fig. 5,
Fig. 7 shows a transfer platform for the access arrangement of Fig. 5 in a storage position,
Fig. 8 shows the transfer platform of Fig. 7 in a transfer position, and
Fig. 9 illustrates use of the access arrangement of Fig. 5. DETAILED DESCRIPTION OF THE DRAWINGS
Fig. 1 illustrates an access arrangement 1 according to a first embodiment of the invention, mounted on an offshore support structure, in the form of a monopile 2, for a wind turbine tower 3. The left part of Fig. 1 shows a perspective view of the monopile 2 and access arrangement 1, and the right part of Fig. 1 shows part of a cross sectional view of the monopile 2 and access arrangement 1.
The access arrangement 1 is provided with a number of steps 4, forming a ladder. The steps 4 are arranged with mutual distance along a longitudinal axis defined by the ladder. The access arrangement 1 is further provided with a number of transfer platforms 5, also arranged with mutual distance along the longitudinal axis defined by the ladder. The transfer platforms 5 are adapted to carry a person during transfer between a sea vessel and the access arrangement 1. Accordingly, the person is allowed to jump from the sea vessel to one of the transfer platforms 5 during transfer from the sea vessel to the access arrangement 1, and to jump from one of the transfer platforms 5 to the sea vessel during transfer from the access arrangement 1 to the sea vessel. This considerably increases the safety during transfer, because a larger area is available for accommodating the person. Furthermore, during transfer from the access arrangement 1 to the sea vessel, the person can be oriented in such a manner that he or she faces the sea vessel during the transfer.
Since the transfer platforms 5 are distributed along the longitudinal axis defined by the ladder, a transfer platform 5 can be selected which is close to the sea vessel, regardless of various conditions, such as tide or waves.
Fig. 2 is a perspective view of the access arrangement 1 of Fig. 1. All of the transfer platforms 5 are in a transfer position, in which the transfer platforms 5 are clear of the steps 4, thereby allowing them to carry a person. However, each of the transfer platforms 5 may be movable between the transfer position shown in Fig. 2 and a storage position in which the transfer platforms 5 are protected from the ambient environment. The storage position for a given transfer platform 5 could advantageously be between two of the steps 4. In this case the transfer platform 5 could be moved from the transfer position to the storage position by pivoting the transfer platform 5 about a substantially vertical axis, swinging the transfer platform 5 towards the steps 4 and into the storage position between the steps 4, where it is protected by the steps 4.
Fig. 3 shows a front view and a side view of the access arrangement 1 of Fig. 1. Fig. 4 is a perspective view of a transfer platform 5 for the access arrangement 1 of Fig. 1. The transfer platform 5 is pivotable about a substantially vertical axis 6, thereby allowing the transfer platform 5 to move between the transfer position and the storage position, as described above with reference to Fig. 2. Fig. 5 illustrates an access arrangement 1 according to a second embodiment of the invention mounted on an offshore support structure, in the form of a monopile 2, for a wind turbine tower.
Similarly to the embodiment illustrated in Figs. 1-4, the access arrangement 1 of Fig. 5 is provided with a plurality of steps 4, forming a ladder, and the steps 4 are arranged with mutual distance along a longitudinal axis defined by the ladder. Furthermore, the access arrangement 1 is provided with a number of transfer platforms 5 arranged with mutual distance along the longitudinal axis defined by the ladder. The transfer platforms 5 are arranged for carrying a person during transfer between a sea vessel 7 and the access arrangement 1, as described above with reference to Fig. 1, thereby increasing the safety during such transfer.
The transfer platforms 5 have a design which differs from the design of the transfer platforms 5 of the access arrangement 1 of Figs. 1-4. This will be described in further detail below.
Fig. 6 is a perspective view of the access arrangement 1 of Fig. 5. Two transfer platforms 5 are shown in Fig. 6. One of the transfer platforms 5a is in a transfer position in which it can carry a person during transfer between a sea vessel and the access arrangement 1, i.e. the transfer platform 5a defines a substantially horizontal surface on which a person can stand during the transfer. The other transfer platform 5b is in a storage position, in which the transfer platform 5b is positioned with the surface against an offshore support structure having the access arrangement 1 mounted thereon. Thereby the transfer platform 5b is protected from the ambient environment. In particular, the transfer platform 5b is protected from collisions with a sea vessel being moored to the offshore support structure.
Each of the transfer platforms 5 is movable between the transfer position and the storage position by rotating the transfer platform 5 about a substantially horizontal axis 8.
The transfer platforms 5 can be locked in the storage position by means of a locking means 9 comprising a tap 10 formed on the transfer platform 5 and a gripping mechanism 11 mounted on the ladder, configured to releasably fix the tap 10. Thereby the transfer platform 5 is prevented from accidentally moving from the storage position to the transfer position. When the transfer platform 5 is in the transfer position, it is prevented from accidentally moving to the storage position, due to gravity.
Fig. 7 shows a transfer platform 5 for the access arrangement 1 of Fig. 5 in a storage position. It can be seen that the locking means 9 is in a locked position where the gripping mechanism 11 fixes the tap 10 formed on the transfer platform 5.
Fig. 8 shows the transfer platform 5 of Fig. 7 in a transfer position. It can be seen that the tap 10 has been brought out of engagement with the gripping mechanism 11, thereby allowing the transfer platform 5 to rotate to the transfer position, allowing the transfer platform 5 to carry a person. Fig. 9 illustrates use of the access arrangement 1 of Fig. 5. The transfer platform 5a which is closest to the sea vessel 7 is in the transfer position, and a person 12 is standing on the transfer platform 5a. Two other transfer platforms 5b are positioned in the storage position.
It is clear from Fig. 9 that the person 12 can easily transfer between the sea vessel 7 and the access arrangement 1, via the transfer platform 5a. It is also clear that the transfer platform 5a defines a surface area which is sufficiently large to allow the person 12 to face the sea vessel 7 during transfer from the access arrangement 1 to the sea vessel 7.

Claims

1. An access arrangement (1) for use with an offshore support structure (2) for a wind turbine, the access arrangement (1) comprising :
- a ladder with a plurality of steps (4) arranged with mutual distance along a
longitudinal axis defined by the ladder, the steps (4) being attached to the offshore support structure (2), and
- at least one transfer platform (5) adapted to carry a person.
2. An access arrangement (1) according to claim 1, wherein the at least one transfer platform (5) is movable between a transfer position in which the transfer platform (5) can carry a person, and a storage position in which the transfer platform (5) is protected from an ambient environment.
3. An access arrangement (1) according to claim 2, wherein the at least one transfer platform (5) is movable between the transfer position and the storage position by pivoting said at least one transfer platform (5) about a substantially vertical axis (6).
4. An access arrangement (1) according to claim 2, wherein the at least one transfer platform (5) is movable between the transfer position and the storage position by pivoting said at least one transfer platform (5) about a substantially horizontal axis (8).
5. An access arrangement (1) according to any of claims 2-4, wherein the at least one transfer platform (5) comprises locking means (9, 10, 11) arranged to releasably lock the transfer platform (5) in the transfer position and/or in the storage position.
6. An access arrangement (1) according to any of claims 2-5, wherein, when the at least one transfer platform (5) is in the storage position, the transfer platform (5) is arranged substantially within a volume defined by the steps (4) of the ladder and a surface of the offshore support structure (2), and wherein, when the at least one transfer platform (5) is in the transfer position, the transfer platform (5) protrudes from said volume.
7. An access arrangement (1) according to any of the preceding claims, wherein the access arrangement (1) comprises a plurality of transfer platforms (5) arranged with mutual distance along the longitudinal axis defined by the ladder.
8. An access arrangement (1) according to any of the preceding claims, wherein the offshore support structure comprises a monopile (2).
9. A monopile (2) for an offshore wind turbine tower foundation, the monopile (2) having an access arrangement (1) according to any of claims 1-8 mounted thereon.
10. A method of accessing an offshore wind turbine tower (3) mounted on an offshore support structure (2) having an access arrangement (1) according to any of claims 1-8 mounted thereon, the method comprising the steps of:
- moving a transfer platform (5) from a storage position to a transfer position,
- allowing personnel to access the wind turbine tower (3) and/or to descend from the wind turbine tower (3), via the transfer platform (5),
- moving the transfer platform (5) from the transfer position to the storage position.
PCT/DK2017/050329 2016-10-07 2017-10-05 An access arrangement for use with an offshore support structure for a wind turbine WO2018065021A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DKPA201670791 2016-10-07
DKPA201670791 2016-10-07

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CN116420018A (en) * 2021-02-22 2023-07-11 株式会社可持续工程 Marine structure, fender device for marine structure, and method for moving unit structure to marine structure

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FR2487423A1 (en) * 1980-07-28 1982-01-29 Petitjean Et Cie Rest-platform for access ladder for lighting tower - has frame which cantilevers normally from ladder segment leaving opening through which climber can pass
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CN116420018B (en) * 2021-02-22 2024-06-07 株式会社可持续工程 Marine structure, fender device for marine structure, and method for moving unit structure to marine structure

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