LIGHT GUIDE ASSEMBLY AND METHOD FOR PROVIDING A TOWER THEREWITH

Abstract

A light guide assembly for a tower, in particular for a wind turbine tower, including a light guide casing arranged to extend substantially through a tower wall, wherein a first end of the light guide casing is provided with a light source, and a second end of the light guide casing is configured for emitting light to an area surrounding the tower.

Claims

1. A light guide assembly for a tower, comprising: a light guide casing arranged to extend substantially through a tower wall, wherein a first end of the light guide casing is configured to receive a light source, and a second end of the light guide casing is configured for emitting light to an area surrounding the tower; wherein, after insertion, the first end is substantially at an inner side of the tower wall and the second end is substantially at an outer side of the tower wall.

2. The light guide assembly according to claim 1, wherein one end of the light guide casing is provided with a retention member.

3. The light guide assembly according to claim 1, wherein the second end of the light guide casing is provided with a transparent dome.

4. The light guide assembly according to claim 1, further comprising a sealing ring arranged to provide a sealing engagement between a hole and the light guide casing.

5. The light guide assembly according to claim 4, further comprising a compressing member arranged to enclose the light guide casing and to compress a sealing ring from the inner side of the tower wall.

6. The light guide assembly according to claim 1, further comprising a tightening element arranged to fixate the light guide casing from the inner side of the tower wall.

7. The light guide assembly according to claim 1, further comprising a light source arranged on a printed circuit board, wherein the light source is arranged to be mounted at the first end of the light guide casing.

8. The light guide assembly according to claim 1, further comprising a housing enclosing the light source, wherein the housing is arranged to be mounted on the first end of the light guide, the first end of the light guide casing extending into the housing.

9. The light guide assembly according to claim 1, further comprising a power supply which is connectable to the light source.

10. A tower provided with at least one light guide assembly according to claim 1.

11. A method comprising: utilizing the light guide assembly according to claim 1 for marking a wind turbine tower.

12. A method for providing a tower with at least one light guide assembly according to claim 1, comprising the steps of: providing a hole in the tower wall; inserting the light guide casing into the hole from the inner wall side outwardly; fixating the light guide casing from the inner wall side; connecting the first end of the light guide casing with a housing enclosing a light source near the inner wall side; and connecting the housing with a power supply.

Description

BRIEF DESCRIPTION

[0017] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0018] FIG. 1 shows a schematic side view of a wind turbine provided with a row of light guide assemblies according to a first aspect of embodiments of the invention;

[0019] FIG. 2 shows a schematic cross-section of a first embodiment of a light guide assembly according to a first aspect of embodiments of the invention; and

[0020] FIG. 3 shows a perspective view on a second embodiment of a light guide assembly according to a first aspect of embodiments of the invention.

DETAILED DESCRIPTION

[0021] FIG. 1 shows a schematic side view of a wind turbine 1 provided with a plurality of light guide assemblies 2. The wind turbine typically includes a tower 3, on which top a nacelle 4 is located containing a drive mechanism, such as a gear train or a direct drive, and the rotor blades 5. On top of the nacelle 4, a beacon light 6 may be installed, indicating the presence of a potentially dangerous construction to flight traffic. As the highest point of the wind turbine 1 is not the tower 3, but rather the blade tip 7 of one of the revolving blades 5, additional warning lights may be required to indicate the height which can be reached by the blade tips 7. As the warning lights are not installed on the revolving blades 5, one or more tower lights 2 can be installed on the tower wall at a height corresponding to the lowest point a blade tip 7 can reach. Flight traffic can then estimate the height said blade tips 7 can reach in the opposite direction. Also, for relatively large towers, i.e. towers larger than a height specified by rules and/or regulations, it may be required to have tower lights 2.

[0022] FIG. 2 shows a schematic cross-section of a first embodiment of a light guide assembly 2 that can be installed through a hole in a tower wall 9. The light guide assembly 2 comprises comprising a casing 17 arranged to extend substantially through a tower wall 9. The casing 17 may be tubular and can be configured to receive a light guide 8 therein. The light guide 8 is arranged to transmit light from a light source 12 at a first end 10 of the light guide assembly 2 towards a second end 13 of the light guide assembly 2 for emitting light to an area surrounding the tower 3. The light guide casing 17 is rigid and arranged for being inserted into a hole in the tower wall 9 such that, after insertion, the first end 10 is substantially at an inner side 16 of the tower wall 9 and the second end 13 is substantially at an outer side 15 of the tower wall 9. The light guide casing 17 can for example have a diameter of approximately 20-30 mm to fit in a hole in the tower wall 9. A length of the light guide casing 17 may be comprised in a range of for example 5-30 cm, or more or less depending on a tower wall thickness. One end of the light guide casing 17 is provided with a flange 18, at the second end 13 of the light guide assembly 2 is provided. The light guide 8 may be centralized within the casing 17 and kept at a distance of the casing 17 with the help of one or more distance keepers 19, here embodied as O-rings, known to the person skilled in the art. The casing 17 can be made of metal, for example of stainless steel. The second end 13 of the light guide assembly 2 may be provided with a transparent dome 21 covering the light guide 8 as a protection. The dome 21 may be transparent to a wide range of wavelengths, for example visible and/or infrared light or any other wavelength. Additionally, the dome 21 may be configured to filter and/or change the wavelengths of the light emitted to the surroundings of the tower 3, for example to filter and/or change the color of the light. The light guide assembly 2 of the embodiment of FIG. 2 further comprises a light source 12. The light source 12 comprises at least one light emitting element, such as for example a light emitting diode or LED, arranged on a printed circuit board 22, or any other carrier 22. The light source 12 may be a single light emitting element, such as a single LED, or a plurality of light emitting elements, such as a plurality of LEDs arranged for example in a row or an array or in any other pattern. The light source 12 may for example emit visible light and/or infrared light, according to, for example, regulations. The light source 12 may for example comprise a plurality of identical light emitting elements such as LEDs, for example all emitting light in approximately the same wavelength, or a mixture of light emitting elements emitting in different colors and/or in visible and/or infrared and/or UV light. The intensity of the emitted light may also be prescribed by official regulations. Also, the color of the emitted light may be regulated. The color of the light emitted in the surroundings of the tower may be obtained for example by the light source 12 itself, by providing a colored light source 12. The light source 12 is arranged to be mounted in or near a housing 28, such that, after insertion of the light guide casing 17 into or through the tower wall 16, the light source 12 is arranged at an inner side 16 of the tower wall 9.

[0023] FIG. 3 shows a perspective view on the embodiment of the light guide assembly 2 of FIG. 2. Various aspects as discussed above for the embodiment of FIG. 2 can also apply to this embodiment and vice versa. The light guide assembly 2 can further comprise a sealing ring 25 arranged to provide a sealing engagement between the hole in the tower wall 9 and the light guide casing 17, between an inner surface of the hole in the tower wall 9 and an outer surface of the casing 17. The sealing ring 25 may be located near the second end 13 of the light guide assembly 2, adjacent to the flange 18 of the casing 17. This sealing ring 25 can for example be made of rubber, such as silicone. The light guide assembly 2 can also include a compressing member 26 arranged to enclose the light guide casing 17 and to compress the sealing ring 25 from the inner side of the tower wall 9 towards an outer side. The compressing member 26 can be a relatively rigid sleeve or casing arranged to resist to and transmit compressive forces from the inside of the tower towards the sealing ring 25. By pushing against the compressing member 26 in a direction towards the second end 13 of the light guide casing 17, the sealing ring 25 is being compressed in the hole of the tower wall and expands in radial direction. This radial expansion of the sealing ring 25 allows for sealing and/or fixation of the light guide assembly 2 into the hole of the tower wall 9. For tightening of the compressing member 26, the light guide assembly 2 can comprise a tightening element 27 arranged to fixate the light guide 8 from the inner side of the tower wall 9. Said tightening element 27 can for example be a screw which can be screwed on an external screw thread on for instance the casing 17. Other tightening elements are possible as well. By mounting the tightening element 27 on the first end 10 of the light guide assembly 2, the tightening element pushes against the compressing element 26, which compresses the sealing ring 25, causing the sealing ring 25 to expand within the hole, such that the light guide casing 17 is fixated within the hole in the tower wall 9. Depending on the length of the light guide assembly and/or of the hole in the tower wall, also more than one sealing element can be used at different positions on the light guide assembly. For example, a sealing element near the second end of the light guide casing and a sealing element near a first end of the light guide casing may be provided for relatively long light guides in relatively long holes in the tower wall, or at any other location.

[0024] The light guide assembly 2 further comprises a housing 28, a box shaped housing, enclosing the light source 12. Said housing 28 is arranged to be mounted on the first end 10 of the light guide 8, on the casing 17 surrounding the light guide 8, the first end 10 of the light guide casing 17 extending into or up to the housing 28. A wall of the housing 28 through which the light guide casing 17 is arranged to extend, may be relatively thick, such as to provide support to the light guide 8 to improve stability and/or alignment. The light guide assembly 2 may also comprise a power supply 29 which is connectable to the light source 12. The power supply 29 may be a separate element and may be arranged to be placed at a distance of the light source 12, or may be integrated within the housing 28. The housing 28 may be arranged to receive connecting elements from the power supply, for example from a lower or an upper side of the housing 28, which allows a compact installation of the light guide assembly.

[0025] In order to install at least one light guide assembly into a tower, for example into a wind turbine tower, a hole needs to be provided in a tower wall 9. The light guide assembly 2 can then be inserted into said hole from an inner wall side 16 towards the outer wall. In order to know the exact position of the second end 13 of the light guide 8, the light guide 8, or the casing 17, can for example be provided with a gauging. Once the desired position is reached, e.g. when the length indicated by the gauge corresponds to the length of the hole in the tower wall, the light guide casing can be fixated within the hole, by causing the sealing ring 25 to expand within the hole, for example by mounting the tightening element 27 on the first end 10 of the light guide 8 and by moving said tightening element 27 against a compressing element 26 transmitting the compression to the sealing ring 25. Alternatively, and/or additionally, a stop element can be provided at the second end 13 of the light guide 8, for example at or near the flange 18 of the casing 17. In an embodiment, the flange 18 may be embodied at least partly resiliently, for example, the flange 18 may have a length extending radially outward with respect to the sealing element 25. A lower part of the flange may be sufficiently rigid to retain the sealing element and an outer end may be sufficiently resilient to be folded during insertion of the light guide assembly 2 into the hole of the tower wall, and to be erected when being pushed through until outside the hole. Then, the erected flange may function as a stop member that indicates when the light guide assembly is being pushed sufficiently far through the hole in the tower wall until the second end of the light guide casing is sufficiently far at or near the outside of the tower wall for directing light in the required light emitting pattern to the environment. Such erection of the resilient part of e.g. a flange can provide for a tactile feedback to the person installing the light guide assembly that a sufficient installation length has been reached. The resilient stop member may also be provided adjacent the flange and/or a spring biased member can be used. Of course, alternative possibilities to indicate that the light guide assembly 2 is sufficiently far inserted into the hole of the tower wall may be provided.

[0026] Connection of the first end 10 of the light guide assembly 2 with a light source 12, and/or connecting said light source 12 with a power supply 29 can then be done on site, or, can be done before installation, substantially simplifying the relatively delicate alignment of the optics within the light guide assembly.

[0027] For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of embodiments of the invention may include embodiments having combinations of all or some of the features described. It may be understood that the embodiments shown have the same or similar components, apart from where they are described as being different.

[0028] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0029] For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements.