The invention relates to a method for inspecting and/or treating a surface of a wind turbine or building. The method is aimed particularly at wind turbines and buildings of a height such that auxiliary means are necessary for the purpose of inspecting and/or treating the surface thereof at height.

Methods are known in practice for inspecting and/or treating a surface of for instance wind turbines. Use is made here of a boom lift. A boom lift is placed at the wind turbine or the building, after which a person on the boom lift can inspect and/or treat the surface of the structure. Such a method has the drawback that placing a boom lift entails considerable cost. Working at height moreover creates a hazardous situation. Access to for instance wind turbines with a boom lift is often also difficult .

An object of the invention is to obviate such drawbacks and to provide a method for inspecting and/or treating a surface of a wind turbine or building which is efficient and effective.

This object is achieved by the method according to the invention, the method comprising the following steps of:

- placing a vehicle on the surface by means of a magnetic or electromagnetic element;

- coupling instruments for inspecting and/or treating the surface to the vehicle;

- displacing the vehicle over the surface; and

- inspecting and/or treating the surface with the

instruments .

Placing the vehicle on the surface by means of a magnetic or electromagnetic element achieves that the vehicle is held on the surface. This makes it possible to move the vehicle over a vertical surface, such as the tower of a wind turbine. It is moreover possible to place the vehicle upside down on a horizontal surface, such as a ceiling. It will be apparent that the vehicle can also be arranged on inclining surfaces. The vehicle preferably comprises a magnetic or electromagnetic element, and the surface comprises a material which is attracted by a magnet. This is for instance a steel tower of a wind turbine or a building with steel cladding.

Alternatively, the vehicle is held on a non-ferromagnetic wall by means of a magnetic or electromagnetic element on the rear side of the surface.

The method according to the invention makes it possible to inspect and/or treat a surface of a wind turbine or building without a boom lift being necessary for this purpose. This saves costs and is moreover safe.

A further advantage of the method according to the invention is that it can be performed in any weather conditions. When boom lifts are used to inspect and/or treat a surface of a wind turbine or building, as known in the prior art, an unsafe situation can occur for the person in the boom lift in some weather conditions. This is avoided with the method according to the invention.

The method according to the invention is moreover particularly advantageous for inspection and/or treatment of a surface of an offshore wind turbine. Offshore wind turbines are inspected and/or treated in the prior art by means of a vessel and a crane, this making inspection or treatment an expensive matter .

The inspection and/or treatment of a surface comprises for instance inspection, painting, sand-blasting or repair. Other treatments are also possible.

In a preferred embodiment according to the invention the treatment comprises of cleaning the surface.

Cleaning in particular is a treatment which must be carried out regularly. In addition to cleaning being important for aesthetic reasons, it can also contribute toward preventing rust formation. Another factor affecting wind turbines is that fouling, particularly oil traces, may be present in the surrounding area. In order to prevent this, a wind turbine must be cleaned in timely and regular manner. A further advantage of the method according to the invention is that the vehicle can be held on the surface between cleans. In contrast to for instance a boom lift, which has to be moved to the wind turbine or the building for each cleaning operation, the vehicle can remain ( semi- ) permanently in place. This is not however required.

In a preferred embodiment according to the invention the method comprises of supplying a liquid. The liquid is for instance paint, water, abrasive or cleaning agent.

By supplying a liquid to the vehicle the surface of the building can be treated with the liquid at the position of the vehicle .

Alternatively, a gas such as air can also be supplied. Air is for instance used to blow a surface clean.

Supplying a liquid preferably comprises of supplying water under pressure. This achieves that the surface can be treated with high-pressure cleaning.

In an advantageous embodiment the method according to the invention comprises of coupling the vehicle to the wind turbine or the building by means of a safety line. This increases safety. In addition, use becomes possible under a wider range of weather conditions without detracting from safety.

This measure achieves that, in the unlikely case the vehicle detaches from the surface, the vehicle is prevented from falling all the way to the ground. The safety line can moreover have an anti-theft function.

In a preferred embodiment the safety line is carried from the vehicle via the wind turbine or the building to a counterweight. The safety line is for instance carried via an arm, winch or other protrusion on the wind turbine or the building. The safety line is preferably carried via a pulley provided on the wind turbine or the building, for instance on an arm, winch or other protrusion.

The safety line is preferably carried from the

counterweight, via the wind turbine or the building, preferably via a pulley arranged on the wind turbine or the building, to a coupling part. This coupling part is connected via a second safety line to the vehicle. The weight of the counterweight is preferably greater than or egual to the weight of the vehicle. The counterweight is preferably placed lower than the vehicle, for instance on the ground in the vicinity of the wind turbine or the building or on a platform of the wind turbine.

A currently preferred embodiment provides a winch system which can raise or lower the safety line, wherein the winch system preferably also forms the counterweight.

An embodiment of the method according to the invention comprises of connecting to the wind turbine or the building a conduit and/or line coupled to the vehicle, such that at least a part of the weight thereof is supported by the wind turbine or the building.

The conduit and/or line can for instance be a cable, tube or hose. Many wind turbines and buildings are already provided with an arm or winch or other protrusion which can serve the purpose of suspending a conduit and/or line therefrom. The invention moreover comprises of providing such an arm or winch or other protrusion on a wind turbine and/or building. By guiding the necessary cabling, hoses, conduits, tubes and/or lines via the arm or winch, a part of the weight thereof is in any case supported by the arm or winch. This for instance prevents the possibility of the vehicle being pulled from the surface. The conduit and/or line is preferably suspended from a zone located above the vehicle during use.

In a further embodiment the method comprises of arranging on the wind turbine or the building a line provided with coupling means, such as a hook, for coupling the line and/or conduit to the line, wherein the line is arranged such that the coupling means can be displaced in height direction.

The supply and/or discharge conduit is coupled to a line, wherein the line is connected to the wind turbine or the building, for instance with an arm, winch or other protrusion arranged thereon. The line can be raised and lowered so that the position of coupling to the supply and/or discharge conduit can be moved upward and downward along the wind turbine or the building. This has the advantage that the distance between the suspension point of the supply and/or discharge conduit relative to the ground is adjustable. This first of all enables a simple coupling of the conduit to the line of the arm or winch. For such a coupling the line is lowered to a height at which the conduit can be easily coupled. Secondly, the suspension point can be displaced when the vehicle moves upward and downward over the surface. This achieves that the length of the supply and/or discharge conduits can remain relatively short.

The line is preferably carried from the coupling means via the wind turbine or the building to a counterweight, preferably via a pulley arranged on the wind turbine or the building. The weight of the counterweight is preferably equal to or greater than the weight of the line and/or conduit. The counterweight is again preferably placed lower than the vehicle during use, such as on the ground or on a platform. A winch system can also be provided in this case.

In a currently preferred embodiment both a safety line as described above and a line with coupling means as described above are provided. A single coupling line preferably forms both said safety line and the line for the coupling means. In this case the coupling line is preferably carried from a counterweight to the coupling means via the wind turbine or the building, preferably via a pulley arranged thereon. The coupling means is connected to the vehicle by a second line, this second line serving as safety line. The conduit and/or line are carried via the coupling means to the respective devices on the ground, such as an aggregate or a water supply. This embodiment must also be understood to include the case in which one outer end of the coupling line is divided, wherein one of the parts of the divided outer end is coupled to the vehicle and one part is coupled to the line and/or conduits.

The method preferably comprises of automatically displacing the safety line, the coupling line and/or the coupling means on the basis of the displacement of the vehicle over the surface of the wind turbine.

This has the advantage that the vehicle and the line connected to the wind turbine or the building do not have to be individually controlled.

The vehicle for instance comprises communication means for communicating to the arm or winch the absolute or relative position of the vehicle.

The coupling means and/or the vehicle are for instance provided with a sensor for determining their relative position.

In a currently preferred embodiment the vehicle comprises an angle measuring device to which the safety line, the coupling line and/or the coupling means can be coupled. The angle measuring device is for instance embodied as a bracket pivotable around a pivot axis. The angle measuring device is preferably watertight. The angle measuring device is substantially insensitive to magnetic influence.

When the vehicle is displaced relative to the safety line, the coupling means and/or the coupling line, the angle measuring device will measure a change of angle. The safety line, the coupling line and/or the coupling means are displaced on the basis of this change so that they co-displace with the vehicle.

A preferred embodiment of the method according to the invention comprises of coupling the vehicle to a power supply of a wind turbine.

When a surface of a wind turbine is inspected and/or treated in accordance with the method according to the invention, the vehicle can be coupled to a power supply of a wind turbine. This achieves that the vehicle can operate without a separate power supply, such as a battery present on the vehicle, being necessary for this purpose.

Alternatively, the vehicle is provided with a battery. Alternatively or additionally, a battery of the vehicle can be charged as required by means of the coupling to the power supply.

In a preferred embodiment the method comprises of providing the vehicle with electrical energy at a low voltage. Making use of a low voltage increases safety. The metal surface of the wind turbine or the building is prevented from being placed under a dangerous voltage, for instance in the case a cable breaks .

The low voltage is for instance less than or equal to 50

V in the case of alternating current and 120 V in the case of direct current.

The method for instance comprises of providing a transformer for transforming a higher voltage, such as the voltage of the power supply of a wind turbine, to the low voltage.

A preferred embodiment of the method according to the invention comprises of providing a control mechanism which realizes automatic operation of the vehicle.

Autonomous operation of the vehicle can in this way be realized. The inspection and/or treatment can hereby be performed without a person having to control the vehicle. This means that, once the vehicle has been placed on the surface of a wind turbine or building and the control mechanism has been activated, no or hardly any human intervention is necessary. The control mechanism for instance comprises a time switch for performing a treatment or inspection at regular intervals. It is possible here to also perform a treatment autonomously, for instance a cleaning, as a result of an inspection.

In an embodiment of the method according to the invention the method comprises of providing a housing for the vehicle on the surface of the wind turbine or the building.

The housing provided on the surface serves as location for stationing the vehicle. The housing preferably comprises a shelter so that the vehicle can be parked in the housing and is thereby exposed as little as possible to the weather conditions. It is moreover possible to provide the housing with a charging mechanism, whereby a battery of the vehicle can be charged. Such a charging station, which is arranged on a wind turbine, is preferably powered by a power supply of the wind turbine. For the purpose of placing the vehicle on the surface and removing the vehicle from the surface, use can be made of a type of ramp construction of for instance wood or plastic.

The invention further relates to a vehicle which can move over a surface, comprising:

- at least one magnetic element for holding the vehicle on the surface; and

- treating means for treating the surface, wherein the treating means can be coupled to a supply conduit for the supply of a fluid.

The vehicle according to the invention is preferably applied in the method as described above.

Such a vehicle has the same advantages and effects as described above for the method.

Providing the treatment means which can be coupled to a supply conduit for the supply of a fluid achieves that liquid, such as paint or water, or gas such as air can be supplied to the treatment means so that the surface on which the vehicle is located can be treated with the fluid.

In a preferred embodiment the vehicle comprises a caterpillar track.

The caterpillar track is preferably a magnetic caterpillar track, i.e. a caterpillar track provided with at least one magnetic element.

Providing the vehicle with a caterpillar track achieves that the vehicle has a large contact surface. A firm attachment to the surface is hereby obtained, i.e. the vehicle is held firmly against the surface.

The caterpillar track is preferably provided with a plurality of magnetic elements, each covering only a part of the caterpillar track in the width direction, i.e. the direction perpendicularly of the normal direction of displacement, and parallel to the rotation direction of the caterpillar track. The magnetic elements are offset here relative to each other in the direction perpendicularly of the width direction, i.e. in the direction of displacement. This has the advantage that the force required to remove from the surface a magnetic element located at the outer end of the caterpillar track is relatively small owing to the small width of the element, while the overall force exerted by the elements for the purpose of holding the vehicle on the surface is relatively great. Instead of offset magnets on one track, it is also possible to provide two or more caterpillar tracks, wherein the magnetic elements of the first caterpillar track are offset relative to the magnetic elements of the second caterpillar track.

In an alternative embodiment according to the invention the vehicle is provided with magnetic elements located at a mutual distance and arranged at an angle relative to the width direction. This achieves a similar advantage.

In a preferred embodiment the vehicle comprises at least two caterpillar tracks pivotable relative to each other. The vehicle can hereby also be applied on curved surfaces. This is particularly advantageous in the use of the vehicle on wind turbines. The tower of a wind turbine usually has a curved surface, such a tower usually being cylindrical. Because the caterpillar tracks are pivotable relative to each other, a good contact can nevertheless be maintained between the caterpillar tracks and the surface of the tower.

The caterpillar tracks are for instance pivotable relative to each other around the longitudinal axis and/or transverse axis of the vehicle. The longitudinal axis runs parallel to the normal direction of displacement and the transverse axis runs parallel to the rotation axis of the caterpillar tracks. The vehicle comprises for instance a main frame on which a first sub-frame and a second sub-frame, each comprising a caterpillar track, are pivotally provided. Each sub-frame preferably comprises a drive, such as an electric motor, operatively connected to the caterpillar track. This has the advantage that a complex pivoting transmission can be dispensed with.

In a possible alternative embodiment the vehicle comprises a main frame and four sub-frames. Each sub-frame comprises a caterpillar track. Arranged on either side of the vehicle are two sub-frames, the caterpillar tracks of which lie mutually in line. All sub-frames are pivotable relative to each other, wherein two pivot axes are in this case defined which are substantially perpendicular relative to each other. Situated for instance on the left-hand side of the vehicle is a first caterpillar track A in line with a second caterpillar track B, and on the right-hand side a third caterpillar track C in line with a fourth caterpillar track D. Both A and C can pivot relative to B and D, and A and B relative to C and D.

In a further preferred embodiment according to the invention the vehicle comprises an arm provided with a wheel, which arm extends in the longitudinal direction of the vehicle. The arm preferably extends to the rear side of the vehicle, i.e. the arm preferably extends downward, for instance vertically or obliguely downward. This effectively prevents the vehicle from tilting over backwards.

The arm preferably has a length of at least half the length of the vehicle, preferably at least once the length of the vehicle and more preferably at least one and a half times the length of the vehicle. It has been found that this achieves the stability of the vehicle that is desirable in practice.

In a further preferred embodiment according to the invention the arm comprises a guide for guiding along the arm a supply conduit coupled to the vehicle.

When a supply conduit is coupled to the vehicle, for instance by means of coupling to the treating means, this supply conduit can be guided along the arm by means of the guide. This achieves that the supply conduit is guided away from the vehicle, thus preventing the possibility of the vehicle running over the conduit. The supply conduit or the supply conduits are moreover prevented from becoming entangled.

The supply conduit can for instance comprise a supply conduit for a fluid, but also a line or cable.

The vehicle preferably comprises a coupling means for coupling a safety line, wherein detection means are provided for detecting a force on the coupling means. It is possible by means of the detection means to detect that the safety line is pulled tight. The detection means comprise for instance an angle measuring device or force meter. In the case the vehicle is located on the surface a relatively small force will be detected, on the basis of which is determined whether the safety line has to be displaced or has to be payed out more. If a great force is detected, this means that the vehicle has fallen from the surface and is hanging from the safety line. In this case a warning signal can be generated.

In a preferred embodiment the vehicle comprises a pushing element displaceable by means of a drive between a rest state and an extended state, wherein in the extended state the pushing element extends beyond what is the underside of the vehicle during use such that the pushing element pushes the vehicle off the surface. This is particularly advantageous when permanent magnets are used.

This enables a simple removal of the vehicle from the surface. The vehicle is held against the surface by the magnetic element, so that some force is necessary to remove the vehicle from the surface. When the pushing element is moved to the extended state, it will make contact with the surface. When the pushing element is then extended or displaced still further, the vehicle will thereby be pressed off the surface.

The drive preferably comprises a battery. This has the advantage that when a malfunction occurs, whereby the vehicle can no longer be displaced, the vehicle can still be removed from the surface. The vehicle is in this case preferably coupled to a safety line of the building or the wind turbine. The vehicle can thus be lowered quickly when the vehicle is located at great height.

Finally, the invention relates to a wind turbine provided with a vehicle as described above.

Such a wind turbine has the same advantages and effects as described above for the vehicle and/or the method. Further advantages, features and details of the invention are elucidated on the basis of preferred exemplary embodiments thereof, wherein reference is made to the accompanying drawings.

- Figure 1 shows a wind turbine provided with a vehicle according to the invention for the purpose of performing the method according to the invention.

- Figure 2 shows a detail of figure 1;

- Figure 3 shows the vehicle of figures 1 and 2 ;

- Figure 4 illustrates an alternative embodiment of the method according to the invention;

- Figure 5 shows an alternative embodiment of the vehicle according to the invention;

- Figure 6 shows in detail the caterpillar track of the vehicle of figure 5; and

- Figures 7 and 8 show the hinges of the caterpillar tracks of the vehicle according to the invention.

Wind turbine 2 (figure 1) is erected from ground surface 4. Vehicle 6 is placed on the surface of wind turbine 2. Vehicle 6 is provided with power by means of cable 8 coupled to power supply 12 of wind turbine 2. A fluid is guided from an external supply device 14 via supply line 16 to vehicle 6. Supply line 16 is suspended here from arm or winch 18 of wind turbine 2 by means of line 17 connected to arm 18 and a coupling 19 provided on the outer end of line 17.

The coupling is displaceable in vertical direction by displacing line 17 as according to arrow A. Winch 18 and vehicle 6 comprise communication means so that the vertical position of coupling 19 can be automatically adjusted to the position of the vehicle. When vehicle 10 moves upward or downward, coupling 19 also moves respectively upward or downward.

Further arranged between vehicle 6 and coupling 19 is a cable 20 which functions as fall protection.

Vehicle 6 is operated by person 21. When vehicle 6 is not being used to inspect or treat surface 10 of wind turbine 2, vehicle 6 can be parked in housing 22. The person 21 (figure 2) operates vehicle 6 by means of control box 23 provided with antenna 24. Alternatively, vehicle 6 comprises a control mechanism which realizes automatic operation of the vehicle (not shown) .

Vehicle 6 comprises a caterpillar track 25 which is provided with magnetic elements 26. Vehicle 6 is held on surface 10 because surface 10 of wind turbine 2 is manufactured from a ferromagnetic material .

Supply line 16 is coupled to spray nozzle 27 of vehicle 6. A cleaning liquid is guided via supply line 16 to spray nozzle 27 for the purpose of cleaning surface 10. Vehicle 6 moreover comprises a brush head 28 with which the surface can be brushed. Vehicle 6 comprises on its side directed toward the ground 4 an extending arm 30 provided with a wheel 32.

Vehicle 6 (figure 3) comprises a camera 34 for inspection the surface 10. Vehicle 6 is provided with a cylinder 36 for moving spray nozzle 27 and/or brush 28 onto or away from the surface. Arm 30 is provided with guides 38 for guiding cables or conduits along arm 30, as represented by cable 8 in the shown embodiment.

In the shown embodiment vehicle 6 weighs about 50 kilograms. Vehicle 6 has a tractive force of about 200 kilograms.

Embodiments with a higher or lower tractive force, for instance 50-200 kg or more than 250 kg, and a higher or lower weight, for instance 35-100 kg, can also be envisaged.

Elements in figures 4-8 similar to elements of figures 1-3 are given the same reference numerals.

A winch system 40 (figure 4) is provided on ground surface 4 in the vicinity of a wind turbine 2. The winch system comprises a driven winch 42 which is able to raise or lower a cable 44. Cable 44 runs from winch 42 to pulley 46 provided on arm 18 of wind turbine 2. The outer end of cable 44 is attached to coupling means 19, for instance a hook.

Vehicle 48 is coupled to coupling means 19 via a safety line 50. Water hose 52 runs via coupling means 19 to vehicle 48 for the purpose of supplying water to clean the surface of tower 10. In addition, a cable 54 runs from vehicle 48 to a control box for operation by person 21.

Vehicle 48 (figure 5) comprises two sets 56, 58 of double caterpillar tracks. The caterpillar tracks of a set comprise magnetic elements 60, 62 which are offset relative to each other. Compared to aligned magnetic elements, this has the advantage that the force required to rotate the caterpillar track is smaller. At the same time the force with which the vehicle is held on the surface is equal to this force in the aligned situation.

A rotating brush 64 is provided on the front side of vehicle 48. This brush 64 has a determined degree of flexibility, i.e. brush 64 can be compressed to a determined extent. Curved surfaces can hereby also be cleaned. Brush 64 is coupled to drive 65.

Vehicle 48 is provided with a bracket 66 with a hooking eye 67 for coupling to safety line 50. Bracket 66 is connected to an angle measuring device 68 which measures the angle which the bracket makes relative to the frame of the vehicle. Angle measuring device 68 is connected to control box 69 so that this latter can process and/or communicate the measured value to the remote control via cable 54.

A set of caterpillar tracks (figure 6) comprises a drive wheel 70 and a rear wheel 72. The wheels are connected to a frame 74.

Drive 76 (figures 7 and 8) of set 56 is also connected to frame 74. Set 58 also comprises such a frame (not shown) to which its drive 78 is also connected. The frames of the sets of double caterpillar tracks 56, 58 can pivot relative to the main frame of vehicle 48, to which control box 69 is also connected, by means of pivot axes 57.

The curvature of the surfaces of figures 7 and 8 differ because figure 7 shows the situation at a lower point along tower 10 compared to figure 8. In the lower position according figure 7 the surface has a smaller curvature, i.e. a larger radius of curvature, than in the position according to figure 8. Because the sets of caterpillar tracks 56, 58 are pivotable relative to each other, the angle between sets 56, 58 is adjusted to the curvature of the surface. This guarantees the largest possible contact surface.

The invention is by no means limited to the above described preferred embodiments thereof. The rights sought are defined by the following claims, within the scope of which many

modifications can be envisaged.