A securing assembly for securing service equipment to an elongated tower

Abstract

The present invention relates to a securing assembly (1) for securing service equipment, such as a support tower of a crane, to a wind turbine tower. The securing assembly (1) comprises two arms (6) arranged movable relative to each other so that the arms can embrace the wind turbine tower (3), and each arm (6) comprises an outer part (6b) including an elongated plate (7) arranged such that the plate can adapt to the curvature of the wind turbine tower. Each of the plates (7) comprises a self-regulating heater (12) arranged to heat the plate.

Description

[0001] A securing assembly for securing service equipment to an elongated tower

[0002] Technical field

[0003] The present invention relates to a securing assembly for securing service equipment, such as a support tower of a crane, to a wind turbine tower.

[0004] Background

[0005] Wind turbines today require regular maintenance of its main components, such as rotor blades, gear boxes and generators. Cranes are used to lift the components to the wind turbine.

[0006] EP3812337A1 discloses an example of a crane comprising an elongated support tower and a lifting arrangement in the top of the support tower. Since the support tower will be very high, the security and stability of the support tower is ensured with a plurality of securing assemblies for securing the support tower to the wind turbine tower to prevent the tower from swaying.

[0007] EP3725731 discloses an example of a securing assembly for securing the elongated support tower to the wind turbine tower. The securing assembly comprises a base part including two arms, each arm comprising an inner part and an outer part, a rope attached to the base part for surrounding the wind turbine tower, a plate arranged at the outer part of each of the two arms. The plates being arranged such that they can adapt to the curvature of the wind turbine tower and each plate comprises at least one rope sliding element, arranged to slidably hold the rope. The rope is arranged along the plate for guiding the rope around the wind turbine tower. The securing assembly comprises a rope tightening device arranged on the base part for tightening the rope. The rope is arranged via the rope sliding elements of the plates such that the rope is used to tighten the plates and the arms around the wind turbine tower.

[0008] Such a securing assembly is dependent on high friction between the wind turbine tower and the plates to keep the securing assembly in place and prevent it from sliding down due to gravity, or to rotating relative the wind turbine tower when the plates are pressed against the wind turbine tower. Accordingly, it is important to ensure high friction between the wind turbine tower and the plates.

[0009] The present disclosure aims to provide an improvement of the securing assembly for securing an elongated support tower to a wind turbine tower.

[0010] This aim is achieved by a securing assembly as defined in claim 1.

[0011] The securing assembly comprises two arms arranged movable relative to each other so that the arms can embrace the wind turbine tower. Each of the arms comprises an outer part including an elongated plate arranged such that the plates can adapt to the curvature of the wind turbine tower. Each of the plates comprises a self-regulating heater arranged to heat the plate.

[0012] With a self-regulating heater is meant a heater which is able to maintain a principally constant temperature without the need of any thermostat or other means of temperature control. A self-regulating heater produces a higher amount of heat when its temperature is low, and a smaller amount of heat when its temperature is high. Thus, the amount of heating of the plates depends on the temperature of the plates and the ambient temperature.

[0013] The friction between the plates and the wind turbine tower can be reduced due to snow, ice and moisture between the wind turbine tower and the plates. Since the heater is selfregulating, the heater is able to keep the plates at a principally constant temperature without the risk of overheating the plates. The self-regulating heaters heat the plates so that that snow and ice between the wind turbine tower and the plates melts and so that moisture between them is vaporized. The present invention ensures high friction between the plates and the wind turbine tower independent of the present weather conditions. Since the heater is selfregulating there is no need of any regulating electronics. Thus, the heater becomes thin, and easy to provide on the plates.

[0014] Preferably, the self-regulating heater is self-limiting and adapted so that they will not exceed a certain temperature that would cause damage to the wind turbine tower. The self-limiting capability of the self-regulating heater ensures that the heater stops the heating when the heater reaches a certain temperature. Preferably, the self-regulating heater is adapted to not exceed a temperature that is below a temperature that would cause damage to the wind turbine tower. Thus, it is possible to avoid that the plates are heated to a temperature that may cause damage to the wind turbine tower. For example, the painting on the wind turbine tower is sensitive for high temperatures. Thus, the self-regulating heater can be adapted to heat the plates up to a temperature that is below a temperature that would cause discolour of the painting on the wind turbine tower.

[0015] According to an embodiment of the invention, the self-regulating heater is arranged on one of the surfaces of the plate and is able to maintain a constant temperature on the surface which it covers. This means that the self-regulating heater is self-regulating in a large number of points over the surface it covers. Preferably, the the self-regulating heater is self-regulating in every point on the surface which it covers. Thus, it is possible to maintain a constant temperature at the surface of the plate so that overheating of a part of the surface is avoided. Overheating of the plate may lead to damage of the wind turbine tower and damage of the ropes used to surround the tower. The self-regulating heater is arranged on one of the surfaces of the plate to facilitate the mounting of the self-regulating heater. According to an embodiment of the invention, the self-regulating heater is adapted so that it will not exceed a temperature between 50°C and 150°C. Preferably, the self-regulating heater is adapted so that it will not exceed a temperature between 50°C and 100°C. Most preferably, the self-regulating heater is adapted so that it will not exceed a temperature between 50°C and 80°C. Temperatures in those intervals will not cause discolour of the painting on the wind turbine tower or cause damage to the ropes but is warm enough to prevent damp and ice between the plate and the wind turbine tower.

[0016] Each plate has an inner surface abutting the wind turbine tower when the arms embrace the tower, and an outer surface facing away from the wind turbine tower and said self-regulating heater. According to an embodiment of the invention, the self-regulating heater is arranged on the outer surface of the plate. This is advantageous since the self-regulating heater will not affect the friction coefficient of the inner surface of the plate, which abut the wind turbine tower.

[0017] According to an embodiment of the invention, the self-regulating heater covers at least 50% of the outer surface of the plate. Preferably, the self-regulating heater covers at least 60% of the outer surface of the plate. Most preferably, the self-regulating heater covers at least 70% of the outer surface of the plate. Thus, the heat is distributed over the plate. This means that a large area of the plate can be kept at an even temperature despite outside temperature fluctuations.

[0018] According to an embodiment of the invention, the inner surface of each of the plates is provided with a friction material with a friction coefficient larger than 0.3. This will increase the friction coefficient between the plates and the wind turbine tower to keep the securing assembly in place.

[0019] According to an embodiment of the invention, the self-regulating heater is a positive temperature coefficient heater. A PTC heater is an electrical resistance heater whose resistance increases significantly with temperature. The self-regulating heater may comprise a plurality of self-regulating Positive Temperature Coefficient element, also known as PTC heating elements, or comprises a Positive Temperature Coefficient (PTC) material. A Positive Temperature Coefficient (PTC) material is temperature self-regulating at every single point.

[0020] According to an embodiment of the invention, the self-regulating heater is a self-regulating PTC heater designed to have a sharp change in resistance at a particular temperature. Below that temperature, the heater produces a large amount of heating power, which tends to raise the temperature of the heater. Above that temperature, the self-regulating heater produces little heating power, which tends to allow the heater to cool. Those heaters are called selfregulating, because they tend to maintain that temperature, even if the applied voltage changes. According to an embodiment of the invention, the thickness of the plates is between 5 and 15 mm. Preferably, the plates are made of metal, such as steel. Thus, heat can easily be conducted from the self-regulating heater on the outer surface of the plate to the inner surface of the plate abutting the wind turbine tower to melt ice, snow or to vaporize moisture located between the inner surface of the plate and the wind turbine tower. Further, the plate is flexible and can be adapted to the curvature of the wind turbine tower.

[0021] According to an embodiment of the invention, the self-regulating heater comprises a selfregulating film attached to one of the surfaces of the plate. Preferably, the self-regulating film is attached to the outer surface of the plate. The term film also covers a foil. The self-regulating film is thin and easy to attach to the plates.

[0022] According to an embodiment of the invention, the self-regulating film comprises electrically conductive PTC rubber. PTC rubber is temperature self-regulating at every single point and thus will keep the surface of the plate at the same temperature over the entire area that is covered by the self-regulating film.

[0023] According to an embodiment of the invention, the heating film comprises a plurality of individual heating elements distributed in the film, or on the surface of the film. The heating film will distribute the heat over the surface of the plates on which the film is applied and cause an even heating of the plate.

[0024] Preferably, the heating film is attached to the outer surface of the plate so that the heating film does not affect the friction coefficient of the inner surface of the plate, which abut the wind turbine tower.

[0025] According to an embodiment of the invention, the heating film is movably attached to the surface of the plate so that the heating film is allowed to move relative to the plate when the plate is bent. Thus, the position of the heating film relative to the plate is adjustable when the plate is bent. For example, the heating film is attaches to the plate by means of a flexible glue. This embodiment prevents the heating film from breaking when the plate is bent around the wind turbine tower.

[0026] According to an embodiment of the invention, the self-regulating heater comprises at least two strips made of said heating film, and the strips are arranged spaced apart along a longitudinal axis of the plate so that at least one elongated space is formed between the strips along the plate. Preferably, the securing assembly comprises at least one rope for surrounding the wind turbine tower and the rope is arranged in the at least one space between the strips. This embodiment prevents the rope from grinding on the heating film and thus damaging the heating film. According to an embodiment of the invention, the heating film is a so-called PTC heating film comprising a plurality of self-regulating positive temperature coefficient heaters distributed in the film.

[0027] Brief ion of the

[0028] The invention will now be explained more closely by the description of different embodiments of the invention and with reference to the appended figures.

[0029] Fig. la shows an example of a securing assembly from a perspective view.

[0030] Fig. lb shows a cross-section through an example of a plate having a self-regulating heater.

[0031] Fig. 2 shows an enlarged portion of an example of a self-regulating heater.

[0032] Fig. 3 shows an example of how the securing assembly embraces a wind turbine tower.

[0033] Fig. 4 shows an example of a plate provided with a heating film in a view from above.

[0034] Fig. 5 shows a cross-section A-A through the plate in figure 4.

[0035] Fig. 6 shows another example of a plate provided with a heating film in a view from above.

[0036] Fig. 7 shows a front part of the securing assembly in use.

[0037] Fig. 8 shows the plate in figure 5 in use with two ropes.

[0038] Detailed

[0039] Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. The securing assembly can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

[0040] Figure la shows an example securing assembly 1 for securing service equipment to a wind turbine tower from a perspective view. The securing assembly 1 comprises two arms 6 arranged movable relative to each other so that the arms can embrace the wind turbine tower. Each arm comprises an inner part 6a and an outer part 6b. Each of the arms 6 comprises an elongated plate 7 at the outer part 6b. The plates 7 being arranged such that they can adapt to the curvature of the wind turbine tower 3. The plates 7 may be pre-bent such that they approximately match the curvature of a wind turbine tower 3 or they can be made flexible so that their shape adapts to the shape of the wind turbine tower 3 when they are pressed against the surface of the wind turbine tower. The plates 7 increase the contact surface between the arms 6 and the wind turbine tower 3 and thus increases the stability of the securing assembly 1. Each of the plates 7 has an inner surface 7a abutting the wind turbine tower when the arms 6 embrace the wind turbine tower, and an outer surface 7b facing away from the wind turbine tower. The plates 7 may comprise steel, plastic, composite material, any kind of metal which allows for the plate 7 to be flexible. Preferably, the plates 7 are made of metal, such as steel, so that they have a high strength and high thermal conductivity. Each of the plates 7 comprises a self-regulating heater 12 arranged to heat the plate. Preferably, the self-regulating heater 12 is also self-limiting and adapted so that its temperature will not exceed a certain temperature selected so that the temperature of the plate 7 will not exceed a temperature that would cause damage to the wind turbine tower. Preferably, the self-regulating heater 12 is an electrical resistance heater whose resistance increases significantly with temperature. Such electrical resistance heater is called a Positive Temperature Coefficient (PTC) heater. Some PTC heaters are designed to have a sharp change in resistance at a particular temperature. These elements are called self-regulating, because they tend to maintain that temperature, even if the applied voltage changes. Below that temperature, the heater produces a large amount of heating power, which tends to raise the temperature of the heater. Above that temperature, the heater produces little heating power, which tends to allow it to cool.

[0041] Preferably, the self-regulating heaters 12 are arranged on the outer surfaces 7b of the plates 7 so that self-regulating heaters 12 do not affect the friction coefficient of the inner surface of the plate, which abut the wind turbine tower. If the plate 7 is pre-bent, the self-regulating heaters 12 is arranged on the convex side of the pre-bent plate 7. Suitably, the self-regulating heaters 12 can be powered from the same power source which provide power to move the arms 6.

[0042] Figure lb shows a cross-section through the plate 7 in figure la. The thickness of the plate 7 is preferably between 5 and 15 mm. Thus, the plates are flexible and the heat will conduct fast from the self-regulating heater 12 disposed on the outer surface 7b of the plate to the inner surface 7a of the plate, which abuts the wind turbine tower.

[0043] In this example, the self-regulating heater 12 comprises a heating film 13 attached to the outer surface 7b of the plate. For example, heating film 13 is attached to the outer surface 7b of the plate by gluing. Preferably, the heating film 13 is arranged on the outer surface 7b of the plate so that the heating film does not affect the friction coefficient of the inner surface of the plate. The heating film 13 is covering a main part of the outer surface 7b of the plate. Preferably, the heating film 13 is covering at least 70% of the outer surface 7b of the plate 7. The heating film 13 may comprise a plurality of heating elements distributed in the heating film. For example, the heating film is made of a polyester film typically made from polyethylene terephthalate or polyethylene napthalate, or from polyimide materials such as Kapton. The heating elements can, for example, be screen-printed onto the polyester film as dots of carbon-based PTC ink. Alternatively, the self-regulating film comprises electrically conductive PTC rubber, such as a Conflux® PTC heater.

[0044] In one embodiment, the heating film 13 is movably attached to the surface 7b of the plate 7 so that the heating film is allowed to move relative to the plate when the plate is bent. Thus, the position of the heating film relative to the plate is adjustable when the plate is bent. This embodiment prevents the heating film from breaking when the plate is bent around the wind turbine tower and is suitable in the case where the plates are not pre-bent, and thus the plates are bent when they are applied to the wind turbine tower. For example, the heating film 13 is attaches to the plate 7 by means of a flexible glue.

[0045] In this example, the inner surface 7a of the plate 7 is provided with a friction material 14 to increase the friction between the plate and the wing turbine tower. Preferably, the friction material 14 has a friction coefficient larger than 0.3. The friction material 14 is thus on the side of the plate 7 which abut the wind turbine tower 3. By arranging a material having a friction of larger than 0.3, the plates 7 the securing assembly 1 will be prevented from rotating relative the wind turbine tower 3 when the plates 7 are pressed against the wind turbine tower 3 by the arms 6 clamping it. The material is, for example, rubber. The friction material 14 is optional.

[0046] Figure 2 shows an enlarged portion of an example of the the self-regulating heater 12. In this example, the self-regulating heater 12 comprises a plurality of individual heating elements 12a. Suitably, the heating elements 12a are distributed over the plate so that the plate 7 can be essentially evenly heated. Suitably, the heating elements are distributed over one of the surfaces 7a, 7b of the plate. In this example, the heating elements 12a are distributed over the outer surface 7b of the plate. The heating elements 12a are preferably self-limiting so that they are adapted to not exceed a temperature that would cause damage to the wind turbine tower. For example, the heating elements 12a are adapted to not exceed 60°C, or 70 °C, or 80 °C. In one embodiment, the heating elements 12a are positive temperature coefficient heaters, called PTC heating element. PTC heaters have a large positive temperature coefficient of resistance, which means if a constant voltage is applied, the element produces a large amount of heat when its temperature is low, and a smaller amount of heat when its temperature is high.

[0047] Figure 3 shows the example securing assembly 1 from a perspective view when it is arranged on a support tower 2 and where the arms 6 are embracing a wind turbine tower 3. Figure 7 shows the front part of the securing assembly 1 in an enlarged view. The invention provides a securing assembly 1 for securing for securing service equipment, such as an elongated a support tower of a crane, to a wind turbine tower 3. The securing assembly 1 comprises a base part including a tower holding part 4. The tower holding part 4 holds the securing assembly 1 to the elongated support tower 2. The tower holding part 4 comprises an opening 4a for receiving the elongated support tower 2, as shown in figure 1. The securing assembly 1 may be lifted to its position and then fastened to the elongated support tower 2 or it may comprise means for climbing the support tower 2. At least one of the arms 6 is movable relative to the other. For example, the inner part 6a of the least one of the arms is rotatably attached to the tower holding part 4.

[0048] The securing assembly comprises at least one rope 18 attached to the base part for at least partly surrounding the wind turbine tower 3. The rope 18 is used to tighten the plates 7 and the arms 6 around the wind turbine tower 3 for increased stability in the grip of the securing assembly 1. According to some aspects, each of the plates 7 comprises at least one rope sliding element 19 aligned along the plate 7 for guiding the rope 18 around the wind turbine tower 3. If the plate 7 is pre-bent, the at least one rope sliding element 19 is arranged on the convex side of the pre-bent steel plate 7. The rope 18 is arranged via the rope sliding elements 19 and a rope tightening device (not shown). The rope is to apply a high contact force on the surface of the wind turbine tower by tightening the rope. A tightening device can be used to tighten the rope around the wind turbine tower and thus more tightly securing the securing assembly to the wind turbine tower.

[0049] According to some aspects, the securing assembly comprises more than one rope 18. It may be advantageous to use more than one rope 18 such that redundancy is acquired and there is no problem if one rope 18 breaks. The ropes 18 are arranged in parallel, one over another, on the rope sliding elements 19 of the plates 7. The ropes 18 are arranged next to each other over the widths of the plates 7 so that they run in parallel along the lengths of the plates 7. The ropes 18 then do not interfere with each other since they are kept separate by the rope sliding elements 19.

[0050] Figure 4 shows another example of a plate 7 provided with a heating film in a view from above. Figure 5 shows a cross-section through the plate 7 in figure 4. In this example, the selfregulating heater comprises two strips 13a-b made of the heating film 13 attached to the outer surface 7b of the plate. The strips 13a-b are arranged in parallel. The strips 13a-b are arranged spaced apart along a longitudinal axis of the plate 7 so that an elongated space 16 is formed between the strips (13a-c) along the plate. The elongated space 16 has a width essentially corresponding to the width of a rope used for surrounding the wind turbine tower. This embodiment prevents the rope from grinding on the heating film and thus damaging the heating film.

[0051] Figure 6 shows yet another example of a plate 7 provided with a heating film in a view from above. In this example, the self-regulating heater comprises three strips 13a-c made of the heating film and attached to the outer surface 7b of the plate 7. The strips 13a-c are arranged in parallel. The strips 13a-c are arranged spaced apart along a longitudinal axis of the plate 7 so that two elongated spaces 16 are formed between the strips 13a-c along the plate. The elongated space 16 has a width essentially corresponding to the width of the ropes used for surrounding the wind turbine tower. This embodiment prevents the ropes from grinding on the heating film and thus damaging the heating film.

[0052] Figure 8 shows the plate 7 in figure 6 in use with two ropes 18 disposed in the elongated spaces 16 between the strips 13a-c. In this embodiment, the securing assembly 1 comprises two ropes 18 for surrounding the wind turbine tower. The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims. For example, the tower holding part 4 and the arms 6 can be designed in different ways.

[0053] Reference list

[0054] 1. securing assembly

[0055] 2. support tower

[0056] 3. wind turbine tower

[0057] 4. tower holding part

[0058] 6. arms

[0059] 6a. inner part of the arms

[0060] 6b. outer part of the arms

[0061] 7. plate

[0062] 7a. inner surface of the plate

[0063] 7b. outer surface of the plate

[0064] 12. self-regulating heater

[0065] 12a. heating elements

[0066] 13. heating film

[0067] 13a-c strips of the heating film

[0068] 14. Friction material

[0069] 16. elongated space

[0070] 18. rope

[0071] 19. rope sliding element

Claims

Claims1. A securing assembly (1) for securing service equipment to a wind turbine tower (3), wherein the securing assembly (1) comprises two arms (6) arranged movable relative to each other so that the arms can embrace the wind turbine tower (3), and each arm (6) comprises an outer part (6b) including an elongated plate (7) arranged such that the plate can adapt to the curvature of the wind turbine tower (3), characterized in that each of the plates (7) comprises a self-regulating heater (12) arranged to heat the plate (7).

2. The securing assembly (1) according to claim 1, wherein said self-regulating heater (12) is arranged on one of the surfaces (7a, 7b) of the plate (7).

3. The securing assembly (1) according to claim 1 or 2, wherein the self-regulating heater (12) is self-limiting and adapted so that it will not exceed a certain temperature that would cause damage to the wind turbine tower.

4. The securing assembly (1) according to claim 3, wherein said self-regulating heater (12) is adapted so that it will not exceed a temperature between 50°C and 150°C, and preferably the self-regulating heater (12) is adapted so that it will not exceed a temperature between 50°C and 100°C.

5. The securing assembly (1) according to any of the previous claims, wherein each plate (7) has an inner surface (7a) for abutting the wind turbine tower when the arms (6) embrace the tower, and an outer surface (7b) facing away from the wind turbine tower and said selfregulating heater (12) is arranged on the outer surface (7b) of the plate.

6. The securing assembly (1) according to claim 5, wherein the inner surface (7a) of each of the plates (7) is provided with a friction material (14) with a friction coefficient larger than 0.3.

7. The securing assembly (1) according to claim 5 or 6, wherein said self-regulating heater (12) comprises a self-regulating film (13) attached to the outer surface (7b) of the plate.

8. The securing assembly (1) according to claim 7, wherein said self-regulating film (13) comprises electrically conductive PTC rubber.

9. The securing assembly (1) according to claim 7 or 8, wherein said self-regulating film (13) is movably attached to the surface (7a, 7b) of the plate (7) so that the self-regulating film is allowed to move relative to the plate (7) when the plate is bent.

10. The securing assembly (1) according to any of the claims 7 - 9, wherein said self-regulating heater (12) comprises at least two strips (13a-c) made of said self-regulating film, and the strips (13a-c) are arranged spaced apart along a longitudinal axis of the plate (7) so that at least one elongated space (16) is formed between the strips (13a-c) along the plate.

11. The securing assembly (1) according to claim 10, wherein the securing assembly (1) comprises at least one rope (18) for surrounding the wind turbine tower (3), and the rope (18) is arranged in said at least one space (16) between the strips (13a-c).

12. The securing assembly (1) according to any of the previous claims, wherein said selfregulating heater (12) comprises positive temperature coefficient heaters (12a).

13. The securing assembly (1) according to any of the previous claims, wherein the plates (7) are made of metal and the thickness of the plates (7) is between 5 and 15 mm.

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