WO2013102460A1

WO2013102460A1 - Suspension system for wind turbines

Info

Publication number: WO2013102460A1
Application number: PCT/DK2012/000135
Authority: WO
Inventors: Kenneth Lott SKOVBO
Original assignee: Sidis Aps
Priority date: 2012-01-02
Filing date: 2012-12-21
Publication date: 2013-07-11

Abstract

The present invention relates to attachment suspension, also called floating suspension (3), which in combination with a wind turbine blade (8) and lifting wires coming from the servicing and maintenance equipment's (5) and/or (7), can result in a horizontal displacement of the suspension point for servicing and maintenance equipment for wind turbines (9). The invention also relates to a method where the suspension is mounted to the servicing and maintenance equipment's lifting wires (7), which when loaded assume the shape of pos. 5 in that the floating suspension (pos. 3) moves the horizontal fix point out on to the blade's leading edge (any given point in the blade's Y direction), thereby achieving a horizontal displacement of the suspension point for the servicing and maintenance equipment.

Description

SUSPENSION SYSTEM FOR WIND TURBINES

Technical field

The present invention relates to a displaceable suspension system for wind turbines, also called a floating suspension.

Background of the invention

Attempts are being made to extend the service lives of wind turbines beyond 20 years, equivalent to approximately 200,000 operating hours during their service lives. By comparison, a normal car runs for 5,000 hours. Such an enormous operation time makes heavy demands on the wind turbine manufacturer's components, not least on the requirements for servicing and maintenance of the installed wind turbines. A distinction is made between interior service (gearbox, bearings, generator, control panels etc.) and exterior service (tower, blades, base etc.).

In the early years of wind turbines, telescopic platforms, cranes, rappelling equipment etc. were mainly used for exterior service. But given the steadily increasing sizes of the turbines and the accompanying greatly increasing hub height, specially built facade hoists hanging on wires from the top of the turbine are now mainly used. These specially built hoists are equipped with an electric winch, which means that they can be freely hoisted up and down, and there are various models and designs. Examples of such freely hanging servicing and maintenance arrangements for wind turbines are described in patent applications WO2007/085265A1, WO2005/064152A2, WO04092577A1, DE10330426A1, DE3228732A1, DE4344210, EP1550779A2, WO 2004081373, WO2009121792 and JP9302915. A common feature of these solutions is that inspection, servicing and maintenance are performed on a blade pointing vertically down, as most wind turbines have a locking function in this position. The individual blade can thus be dealt with separately.

Today's big wind turbines have hub heights of up to several hundred metres, blade and tower dimensions far bigger than buses, surface areas of many hundreds of square metres, and blade tips which can be up to 20 metres from the tower. Existing suspended equipment is therefore unable to reach the tip of the blade, and/or the difference between the dimensions of the blade tip and its root is so great that the "workplace" is far from optimal. There is every indication that wind turbines will continue to grow in size, and the problem will only escalate in the future. The existing facade hoists can therefore no longer cope with the job, and innovative thinking is required.

Another factor is the fact that standards and maintenance plans for repairs and maintenance of wind turbine blades and towers are increasingly being drawn up, thereby placing greater demands on the servicing and maintenance equipment of the future. When, for example, servicing and maintenance is performed on the blade, the climatic conditions play a very major role as gel coating only can be done on dry surfaces and where the temperature is above 15 degrees Centigrade. These climatic conditions often cannot be accommodated with existing equipment, and cranes are often used to lower the blade down to the ground, where repairs can be made in a temporary tent hall or by transporting to a factory. These actions are extremely costly.

For offshore wind turbines, the need for various servicing and maintenance equipment is even greater, as the costs to this day are exploding high. At sea it is not an option to place the blade on the ground. The use of rappelling equipment is severely limited in servicing and maintenance, as the system is very sensitive to climatic effects (especially wind) and it is unable to ensure "reasonable" working conditions required for more comprehensive repairs. It is therefore classified as unsuitable for anything other than inspection or superficial repairs. This also often involves a compromise with respect to safety.

Summary of the invention

In light of the above, a purpose of the present invention is thus to indicate a solution which makes it simpler and easier to inspect the blades on a wind turbine, especially those of big turbines. Firstly, the present invention relates to attachment suspension for temporary mounting on a blade of a wind turbine, through which suspension one or more lifting wires connect servicing and maintenance equipment to mounting equipment on the turbine, mainly in the nacelle of the wind turbine, where the suspension includes a means for displacing the suspension in the longitudinal direction of the blade. The suspension is placed on the blade in such manner that lifting wires connected to e.g. the turbine's service crane in the nacelle can easily be led through the suspension and down to the service and maintenance equipment. The suspension comprises means for displacement in the longitudinal direction of the blade, i.e. in a direction from the blade's fixing point at the hub out to the tip of the blade. When the suspension is displaced, in principle in the vertical direction relative to the surface on which the wind turbine is placed when the blade is locked in position for servicing, there will be a horizontal displacement of the servicing and maintenance equipment, which will ensure that this equipment is as close to the blade as possible.

The lifting wires are typically steel wires, fixed e.g. to the turbine's service crane in the nacelle, after which another end of the wires is fixed to the servicing and maintenance equipment. In practice this can be done by a person crawling up to the nacelle and throwing down a rope or cable which is then used to pull the lifting wires up to the nacelle.

The suspension comprises means for displacement along the blade. The means can be e.g. rollers, wheels, air cushions, sliding plates, or a combination of two or more of these. Rollers, wheels, air cushions and sliding plates are particularly suitable for the purpose as they can ensure that the suspension can be displaced along the blade without damaging it.

The means of displacing the suspension can also include at least one motor-driven lifting system such as a winch or a crane, preferably in combination with rollers, wheels, air cushions, sliding panels or a combination of two or more of these. The servicing and maintenance equipment can be a wide range of items used for inspection, servicing and maintenance of the blade, but it is preferably service platforms, cleaning equipment, surface treatment equipment, scanning equipment or testing and inspection equipment. In a preferred embodiment of the suspension according to the invention, the servicing and maintenance equipment is based on a flexible frame which can be adapted to the blade's circumference, e.g. a service platform. Such a service platform is highly practical in maintenance work on the blade. The suspension also comprises an embodiment where the suspension is equipped with one or more lifting systems, which can be motor-driven winches or cranes which enable the suspension to displace itself along the blade without damaging it or its surface. It will often be preferable to use the lifting systems to raise and lower the servicing and maintenance equipment rather than using the wind turbine's service crane.

The present invention also relates to a method of raising servicing and maintenance equipment up along a blade mounted on a wind turbine, where the method includes the following steps:

Locking the blade in a downwards vertical direction;

- Placing the servicing and maintenance equipment under the tip of the blade;

Connecting the servicing and maintenance equipment to a fixing point on the wind turbine using one or more lifting wires;

Raising a suspension up from the servicing and maintenance equipment using lifting wires and mounting it on the blade;

- Raising servicing and maintenance equipment up to and along the blade with lifting wires led through the suspension;

where the suspension can be displaced upwards or downwards in the longitudinal direction of the blade. The method according to the invention, where a suspension is mounted on the blade which connects the servicing and maintenance equipment to a fixing point on the wind turbine using lifting wires (e.g. the lifting wires can be connected to the wind turbine's service crane in the nacelle), gives greater flexibility and the possibility of raising the servicing and maintenance equipment up along the blade and servicing the blade.

The suspension can also comprise lifting systems which, for example, can be winches or cranes. The lifting systems ensure that the suspension can be displaced along the blade without the aid of the wind turbine's lifting equipment, and the lifting systems can thus be used to displace the suspension upwards or downwards along the blade. This gives a high level of flexibility and freedom when working on the blade.

The lifting systems can also be used to raise or lower the servicing and maintenance equipment, which also increases flexibility when working on the blade. The method according to the invention has the further advantage that a displacement of the suspension in the longitudinal direction of the blade will result in a horizontal displacement of the servicing or maintenance equipment, such that the servicing or maintenance equipment is always close to the blade.

When the servicing and/or maintenance has been performed, the suspension is removed from the blade.

Description of the invention

The invention is described below with reference to specific individual embodiments and with reference to two drawings, where:

Drawing 1 shows a wind turbine system where a suspension according to the invention is mounted on one blade, and

Drawing 2 shows an embodiment of a service platform based on a flexible frame which can be used according to the invention.

When the suspension according to the invention is to be mounted, the following procedure is used. The wind turbine is stopped and the blade is brought into a downward-standing position and secured/fixed in this position via the turbine's safety system. The servicing and maintenance equipment is set up and installed like already existing equipment, i.e., lifting wires are lifted/pulled up in the wind turbine and fixed to its supporting construction in the top, pos. 2 (nacelle, hub, axle, frame, gearbox etc.). Support and safety wires are pulled up as needed and required. A distinction is made between servicing and maintenance which only involves lifting of materials, and servicing and maintenance equipment, which can handle the lifting of people (e.g. a work platform). The latter involves greater requirements concerning safety, and thereby e.g. concerning the number of lifting wires, and the present invention relates to both systems.

The servicing and maintenance equipment which was transported to/placed at the "foot" of the turbine is now attached to these lifting wires and tightened (pos. 7), and via the lifting winch, it can now raise itself up to the wind turbine (lifting wires may be rolled up directly on the servicing and maintenance equipment, and has been pulled off/rolled off instead).

The various servicing and maintenance equipment includes the following: - Service platform (forms a flexible work platform for equipment/personnel around the blade), with or without climate screen

Cleaning equipment (physical washing, rinsing, blowing equipment - all conceivable media) etc.

Surface treatment equipment (painting, spraying systems, repairing equipment for blades etc.)

Sanding and polishing equipment (manual and automatic)

Scanning, X-ray and photographic equipment.

The above equipment can be built up as a permanent frame, or mounted/built on a flexible frame as shown in drawing 2. This flexible frame is built up of minimum pos. 10, 14 and 15, and connected to parallel arms (as illustrated in pos. 17). A variable cylinder/actuator (as illustrated in pos. 16) can freely change the shape of the platform with the mechanical reservation that pos. 14 and 15 are always parallel to each other. Shock pads are mounted between the blades and the platform frame to protect the blade against impacts etc. Rollers/sliding plates are mounted on the platform frame pos. 1 to ensure that the tower and the platform frame do not damage each other (during raising/lowering). The lifting wires and winch are fixed to the platform frame as shown in pos. 12 and 13, and the flexible frame's secondary function is to absorb the forces, torque, moments etc. arising during lifting/use so that as far as possible, the frame is always level horizontally(pos. 14 and 15 in relation to each other are especially important). The platform frame can also be equipped with a projection function which can increase the distance between tower and platform (not shown in the drawings). The suspension point is now displaced horizontally so that the servicing and maintenance equipment can "reach out" on/to the blade. The servicing and maintenance equipment is now lifted up to a height on the wind turbine where the leading edge of pos. 9 passes the blade's leading edge. (This point depends on the wind turbine's size, model etc.). The floating suspension is fixed to the servicing and maintenance equipment's lifting wires (pos. 7, which in load-carrying form assumes the form of pos. 5), such that the floating suspension (pos. 3) moves the horizontal reference point out on the blade's leading edge (any given point in the blade's Y direction), thereby achieving a horizontal displacement of the suspension point for the servicing and maintenance equipment. The floating suspension (pos. 3) can also be fixed directly to the servicing and maintenance equipment (pos. 9) via wires or similar (no direct contact with the lifting wires pos. 5 or 7).

The floating suspension's (pos. 3) contact point on the actual blade can be performed as a physical point of contact and/or have an "air cushion function" which floats on the blade's leading edge (the floating winch's physical shape/construction can be all conceivable constructions/materials). The floating suspension can also be equipped with vertical lifting systems (pos. 4, manual and automatic) which, via a vertical displacement (pos. A) of the floating suspension results in horizontal displacement (pos. B) of the servicing and maintenance equipment. The suspension point's horizontal level thus matches the displacement of the blade in level X. The floating suspension can also be combined with support points directly between the servicing and maintenance equipment (pos. 9) and with the wind turbine's load-bearing structure. It could, for example, have the shape of pos. 7, which is fixed in pos. 2, and/or a structure fixed to the actual tower (pos. 10 which supports on pos. 6), without being in direct contact with the floating winch.

A floating suspension 3 in combination with wind turbine blade 8 and the servicing and maintenance equipment's lifting wires 5 and/or 7 thus gives a horizontal displacement of the suspension point for the servicing and maintenance equipment for wind turbines 9. The attachment point 2 for lifting wires can be all load-bearing structures in the wind turbine's top section such as tower, nacelle, frame, gearbox, blades, hub etc.

The floating suspension is fixed to the servicing and maintenance equipment's lifting wires 7, which when under load assume the shape of pos. 5, in that the floating suspension (pos. 3) displaces the horizontal reference point out on to the blade's leading edge (any given point in the blade's Y direction), thereby achieving a horizontal displacement of the suspension point for the servicing and maintenance equipment.

The floating suspension (pos. 3) can also be fixed directly to the servicing and maintenance equipment (pos. 9) via wires or similar (no direct contact with lifting wires* pos. 5 or 7).

The floating suspension's (pos. 3) contact point on the actual blade can be performed as a physical contact point and/or have an "air cushion function" which floats on the blade's leading edge.

The floating suspension according to the invention can also be equipped with vertical lifting arrangements (pos. 4, manual and automatic) which, via a vertical displacement (pos. A) of the floating suspension results in horizontal displacement (pos. B) of the servicing and maintenance equipment.

The suspension point's horizontal level thus matches the blade's displacement in level X.

The floating suspension can also be combined with supporting points directly between the servicing and maintenance equipment (pos. 9) and to the wind turbine's load-bearing structure. This can, for example, be as shown in pos. 7, which is fixed to pos. 2 and/or a structure fixed to the tower itself (pos. 10 which supports pos. 6) without being in direct contact with the floating winch.

The servicing and maintenance equipment (pos. 9) can be as follows (with and without operating personnel - man lift) and be constructed as a fixed frame or on a variable frame as shown in drawing 2.

Servicing and maintenance equipment for the wind turbine blade (item 8) :

i. Service platform (flexible work platform for equipment/personnel around the blade), with or without climate screen

ii. Cleaning equipment (physical washing, rinsing, blowing equipment - all conceivable media etc.)

iii. Surface treatment equipment (painting, spraying systems, repair equipment for wind turbine blades etc.)

iv. Sanding and polishing equipment (manual and automatic)

v. Scanning, X-ray and photographic equipment

vi. Servicing and maintenance equipment for repairs to the tower (pos. 6), where a displacement of the suspension point for the servicing and maintenance equipment can be an advantage.

vii. Servicing and maintenance for replacement of and repairs to equipment in the nacelle (pos.

20) of the wind turbine, where a displacement of the suspension point for the servicing and maintenance equipment can be an advantage.

The present invention thus indicates an advantageous suspension, also called a floating suspension 3, which in combination with a wind turbine blade 8 and lifting wires from the servicing and maintenance equipment's 5 and/or 7, can effect a horizontal displacement of the suspension point for the servicing and maintenance equipment for wind turbines 9 such that the servicing and maintenance equipment is brought close to the blade. The invention also indicates a method where the suspension is fixed to the servicing and maintenance equipment's lifting wires 7, which in load- carrying form are shown as pos. 5, in that the suspension (pos. 3) moving the horizontal fixing point out to the blade's leading edge (any given point in the blade's Y direction), and thereby gaining a horizontal displacement of the suspension point for the servicing and maintenance equipment.

Claims

1. Floating suspension for temporary mounting on a wind turbine blade in a wind turbine, through which floating suspension, one or more lifting wires can connect servicing and maintenance equipment (9) to mounting equipment (2) on the wind turbine, characterised in, that the floating suspension comprises means for displacement of the floating suspension in the longitudinal direction of the wind turbine blade.

2. Floating suspension according to claim 1, where the means for displacement of the floating suspension include one or more rollers, wheels, air cushions, sliding panels, or a combination of two or more of these.

3. Floating suspension according to claim 1 or 2, where the means for displacement of the floating suspension comprise at least one motor-driven lifting arrangement preferably in combination with one or more rollers, wheels, air cushions, sliding panels, or a combination of two or more of these.

4. Floating suspension according to any of the claims 1 to 3, where the servicing and maintenance equipment is based on a flexible frame which can be adapted to the blade's circumference.

5. Floating suspension according to any of the claims i to 4, where the servicing and maintenance equipment can be a service platform, cleaning equipment, surface treatment equipment, scanning equipment and testing equipment.

6. Floating suspension according to any of the claims 1 to 5, where the mounting equipment on the wind turbine is the wind turbine's load-bearing construction at the top (nacelle, hub, axle, frame, gearbox etc.).

7. Method for hoisting servicing and maintenance equipment up along a blade mounted on a wind turbine comprising the following steps:

- locking the blade in a downwards vertical direction;

- placing the servicing and maintenance equipment under the tip of the blade;

- connecting the servicing and maintenance equipment to a fixing point on the wind turbine using one or more lifting wires;

- hoisting a floating suspension from the servicing and maintenance equipment and mounting it temporarily on the blade;

- hoisting the servicing and installation equipment up to and along the blade with lifting wires led through the floating suspension;

characterised in, that the floating suspension can be displaced upwards or downwards in the longitudinal direction of the blade.

8. Method according to claim 7, where the floating suspension comprises lifting arrangements.

9. Method according to claim 8, where the lifting arrangements are used to displace the floating suspension upwards or downwards along the blade.

10. Method according toclaim 8 or 9, where the lifting arrangements are used to raise or lower the servicing or maintenance equipment.

11. Method according to any of the claims 7 to 10, where a displacement of the floating suspension in the longitudinal direction of the blade results in a horizontal displacement of the servicing or maintenance equipment.