LEAK CONTAINMENT ARRANGEMENT

Abstract

A leak containment arrangement for a fluid damper in a wind turbine tower includes a receptacle arranged below the fluid damper; a fluid guide arranged between the fluid damper and the receptacle, which fluid guide is arranged to receive fluid from a leak in the damper and to guide the leaked fluid into the receptacle; and a sensing means arranged to detect fluid in the receptacle. Further provided is a method of providing leak containment for a fluid damper in a wind turbine tower.

Claims

1. A leak containment arrangement for a fluid damper in a wind turbine tower, comprising: a receptacle arranged below the fluid damper; a fluid guide arranged between the fluid damper and the receptacle, wherein the fluid guide is arranged to receive fluid from a leak in the fluid damper and to guide the fluid into the receptacle; and a sensing means arranged to detect the fluid in the receptacle.

2. The leak containment arrangement according to claim 1, wherein a projected surface area of the fluid guide contains a projected surface area of the fluid damper.

3. The leak containment arrangement according to claim 1, wherein the sensing means is configured to issue an alarm when a level of collected fluid in the receptacle is detected and/or when the level of collected fluid in the receptacle rises faster than a predefined rate.

4. The leak containment arrangement according to claim 1, further comprising a fluid return means for returning any collected fluid to the fluid damper.

5. The leak containment arrangement according to claim 4, wherein the fluid return means comprises a pump arranged to convey fluid through a return line to the fluid damper.

6. The leak containment arrangement according to claim 5, wherein the sensing means is configured to actuate the pump when fluid is detected in the receptacle.

7. The leak containment arrangement according to claim 1, wherein a run-off surface of the fluid guide comprises any of: polyethylene, polyvinylchloride, polypropylene.

8. The leak containment arrangement according to claim 1, wherein a run-off surface of the fluid guide is in a shape of a downward-pointing cone.

9. The leak containment arrangement according to claim 1, wherein an outer edge of the fluid guide is secured to an interior surface of a tower wall.

10. The leak containment arrangement according to claim 1, wherein the fluid guide comprises a weight-bearing support structure and a fluid run-off surface arranged on the weight-bearing support structure.

11. The leak containment arrangement according to claim 10, wherein the support structure comprises a rope mesh in a form of a funnel.

12. A method of providing leak containment for a fluid damper in a wind turbine tower, comprising: arranging a receptacle below the fluid damper; arranging a fluid guide between the fluid damper and the receptacle to receive fluid from a leak in the fluid damper and to guide the fluid into the receptacle; and providing a sensing means for detecting the fluid in the receptacle.

13. The method according to claim 12, further comprising actuating a fluid return means when a level of fluid collected in the receptacle exceeds a threshold level.

14. A wind turbine comprising: a tower supporting a nacelle; a fluid damper arranged in an upper level of the tower; and the leak containment arrangement according to claim 1 arranged to collect fluid leaked from the fluid damper.

15. The wind turbine according to claim 14, wherein the fluid damper comprises a fluid-filled toroid with an outer diameter that corresponds to an inner diameter of the tower.

Description

BRIEF DESCRIPTION

[0041] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0042] FIG. 1 shows an embodiment of a leak containment arrangement;

[0043] FIG. 2 shows another embodiment of a leak containment arrangement;

[0044] FIG. 3 shows a top-down view of an embodiment of the leak containment arrangement;

[0045] FIG. 4 shows a vertical cross-section view of an embodiment of the leak containment arrangement;

[0046] FIG. 5 shows another embodiment of a leak containment arrangement;

[0047] FIG. 6 shows another embodiments of a leak containment arrangement; and

[0048] FIG. 7 shows a leak containment arrangement as known from the prior art.

DETAILED DESCRIPTION

[0049] FIG. 1 shows a schematic cross-section through a wind turbine tower 20, showing a liquid damper 3 arranged at an upper level in the tower 20 (other components of the operational wind turbine, such as the nacelle, generator etc., are not shown). In an exemplary embodiment, the outer diameter, the inner diameter, and the height of the slosh damper can be 6 m, 3.5 m, and 1.5 m respectively. The capacity of the damper 3 can be in the order of 15 m.sup.3 (15,000 litres) or even more. The wind turbine operator may be required by locally applicable regulations to provide a secondary containment for the damper 3 so that liquid leaking from the damper 3 can be collected.

[0050] To fulfil these requirements, the wind turbine tower 20 has been equipped with an embodiment of the inventive leak containment arrangement 1.

[0051] The leak containment arrangement 1 comprises a receptacle 11 and a fluid guide 10 arranged between the fluid damper 3 and a receptacle 11. The fluid guide 10 is arranged to receive liquid originating from a leak X in the damper 3 and to guide the leaked fluid into the receptacle 11. The receptacle 11 can be small compared to the damper capacity. For example, the receptacle 11 may be dimensioned to hold at most 10%, more desirably at most 1-2% of the liquid contained in the damper 3.

[0052] The diagram shows one mode of realizing the fluid guide 10. In this embodiment, the fluid guide 10 is realised as an annular catchment surface suspended underneath the toroidal damper 3. The fluid guide 10 is secured underneath the damper 3, for example using magnets 17 between the outer edge of the fluid guide 10 and the tower wall, and suspension points 15 at suitable positions on the damper 3. The lowest point of the fluid guide 10 is a funnel that opens into the receptacle 11.

[0053] The diagram indicates a level sensor 13 arranged to monitor the level of liquid in the receptacle 11. When the liquid level reaches a predefined threshold 12L, a signal 13S from the sensor 13 is sent to a processing module, for example the wind turbine controller 21 (indicated here schematically), which in turn can issue an alarm 13A to the wind turbine operator so that a repair crew can be sent to the wind turbine in order to repair the leak X in the damper 3.

[0054] The inventive secondary containment system 1 has a significantly lower weight compared to a welded steel tank as known from the prior art, with a capacity that is the same (or larger) than the slosh damper 3. The inventive secondary containment system 1 is also considerably cheaper than the prior art solutions and can be installed in a favourably brief time.

[0055] FIG. 2 shows another exemplary embodiment. Here, the fluid guide 10 has the shape of an asymmetrical downward-pointing cone with an opening arranged over the receptacle 11. Any leaked liquid 3F.sub.leak runs down the upper surface or run-off surface 10R of the fluid guide 10, and into the receptacle 11. The diagram also shows a fluid return means provided for this exemplary embodiment. The fluid return means comprises a return line 121 and a pump 122, for returning any collected fluid 3F.sub.leak to the damper 3. The diagram indicates the general asymmetric shape of the fluid guide 10, which shall be understood to be shaped to include a central passage to accommodate at least the power cables.

[0056] Similar to the embodiment of FIG. 1, the diagram indicates a level sensor 13 arranged to monitor the level of liquid in the receptacle 11. When the liquid level reaches a predefined threshold 12L, an appropriate signal 13S can be issued by the sensor 13.

[0057] A further option is illustrated in FIG. 3. Here, in addition to the conical run-off surface illustrated in FIG. 1, the fluid guide 10 comprises an additional collar 10C or curtain arranged between the tower wall and the run-off surface 10R, to ensure that any liquid originating very close to the tower wall will also be guided onto the run-off surface 10R of the fluid guide 10. The upper edge of this collar 10C can be taped, riveted, stapled, or otherwise attached to the tower interior surface. The upper edge of the conical portion can be connected to the tower wall in any suitable manner, for example by means of an annular arrangement of hooks 14 or other fasteners. The outer edge of the fluid guide 10 can be provided with eyelets 1 or loops to facilitate attachment to the hooks 14.

[0058] The collar 10C can be shaped such that its lower edge is below the level of the suspension points 14, so that the lower edge of the collar 10C reaches the run-off surface 10R of the fluid guide 10. The leak containment arrangement 1 may be assumed to also comprise a fluid return means as shown in FIG. 1. Here also, the diagram indicates the general asymmetric shape of the fluid guide 10, which shall be understood to be shaped to include a central passage to accommodate at least the power cables.

[0059] FIG. 4 and FIG. 5 illustrate a further way of realizing the fluid guide 10. FIG. 3 shows a top-down view, looking downward into the tower 20, while FIG. 4 shows a vertical cross-section. Here, a two-part configuration is shown, with a robust rope mesh 101 or net formed in the shape of a downward-pointing cone, to act as a support structure for a separate run-off surface 10R. The rope mesh 101 can be suspended from the tower wall as described above, for example using suitable hooks 14. A run-off surface 10R in the form of a similar-sized cone or funnel is arranged above the supporting rope mesh 101. FIG. 4 illustrates a step in which the run-off surface 10R is being unrolled to arrange it on top of the supporting mesh 101. The upper edge of the run-off surface 10R can be taped, riveted, stapled, or otherwise connected to the tower wall interior surface. Since the material of the run-off surface 10R does not need to bear any weight, it can be made of a favourably economical lightweight material. Instead of the symmetrical conical shape shown here, the fluid guide can have an asymmetrical shape as suggested in FIG. 1, to allow the receptacle 11 to be arranged nearer to the tower wall. The leak containment arrangement 1 may be assumed to also comprise a fluid return means as shown in FIG. 1.

[0060] FIG. 6 shows an alternative way of realizing the fluid guide 10. Here, instead of having the shape of a downward-pointing cone as shown above in FIGS. 1-3, the fluid guide 10 has the shape of an upward-pointing cone. Any leaked liquid runs down the upper surface of the cone towards a narrow channel 110 (a gutter or trough) arranged about the interior surface of the tower wall, and formed to lead towards a receptacle 11. For example, the lower edge of the fluid guide 10 and the gutter can have the shape of an ellipse. The ellipse described by the gutter may be defined by an inclined plane intersecting with the tower. The circular upper edge of the fluid guide 10 can be secured to the inner wall of the damper 3 at its central opening, for example. The elliptical lower edge of the fluid guide 10 can be secured in any suitable way to an upper edge of the elliptical gutter 110. At its lowest point, the gutter 110 opens into a receptacle 11 as described above. The leak containment arrangement 1 may be assumed to also comprise a fluid return means as shown in FIG. 1.

[0061] FIG. 7 shows a cross-section through a wind turbine tower 20 as known from the prior art, showing a full-size slosh damper 4 arranged at an upper level in the tower 20. Similar to the wind turbine tower shown in FIG. 1, the capacity of the damper 4 can be in the order of 15,000 litres. To fulfil the requirements of secondary containment for the damper fluid, the damper 4 is arranged in a secondary containment tank 5.

[0062] Environmental regulations may require that the secondary containment tank 5 be constructed to contain the entire quantity of damper fluid in the event of a leak. However, the material costs of providing a containment tank that is large enough (and structurally strong enough) to contain such a quantity of fluid add significantly to the overall cost of manufacturing the wind turbine.

[0063] 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.

[0064] 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.