WIND TURBINE TOWER WITH CRANE CONNECTION ELEMENTS AND A CRANE WITH TOWER FLANGE CONNECTION ELEMENTS

Abstract

A crane (2) comprising a base portion (4), two arms (6, 8) displaceably connected to the base portion and a lifting boom (22) displaceably connected to the base portion, said lifting boom being provided with a lifting wire (32) and a lifting member (30), for example a lifting hook, for lifting a load, wherein the two arms and the base portion in combination comprise at least three tower flange connection element (10) is arranged to be detachably connectable to cooperating crane connection elements on a flange of a wind turbine tower section, wherein each arm comprises one of the tower flange connection elements, and wherein the vertical distance between any two tower flange connection elements in the normal operating position of the crane is less than 1 m, less than 50 cm or less than 25 cm. In this way a crane is provided which can be attached to a flange located at the upper portion of a tower section.

Claims

1. A wind turbine tower comprising a first tower section, said first tower section having an upper flange arranged at an upper end of the first tower section, said upper flange comprising one or more flange portions which extend(s) horizontally out past the outer surface of the main body of the first tower section, said one or more flange portion(s) together comprising at least three crane connection elements, the vertical distance between any two of said at least three crane connection elements being less than 1 m, a. each of said at least three crane connection elements being arranged such that a cooperating tower flange connection element on a crane can be detachably connected to said crane connection element, and b. said at least three crane connection elements being spaced around the circumference of the first tower section.

2. Wind turbine tower according to claim 1, wherein the flange comprises four crane connection elements, and where a vector A between a first and a second crane connection element has a length of at least 200 cm and a vector B between a third and a fourth crane connection element has a length of at least 200 cm.

3. Wind turbine tower according to claim 1, wherein said at least three crane connection elements are arranged on essentially the same plane.

4. Wind turbine tower according to claim 1, wherein the vertical distance between any three of said at least three crane connection elements is less than 50 cm.

5. Wind turbine tower according to claim 1, wherein the vertical distance between the uppermost of any three of said at least three crane connection elements and the lowermost of any three of said at least three crane connection elements is less than 50 cm or less than 25 cm.

6. Wind turbine tower according to claim 1, wherein the wind turbine tower further comprises a second tower section arranged on top of the first tower section, the second tower section having an upper flange comprising one or more flange portions which extend(s) horizontally out past the outer surface of the main body of the first tower section, said one or more flange portion(s) together comprising at least three crane connection elements, the vertical distance between any two of said at least three crane connection elements being less than 1 m, a. each of said at least three crane connection elements being arranged such that a cooperating tower flange connection element on a crane can be detachably connected to said crane connection element and b. said at least three crane connection elements being spaced around the circumference of the first tower section.

7. Wind turbine tower according to claim 6, wherein the flange of the second tower section comprises four crane connection elements, and where a vector C between a first and a second crane connection element has a length of at least 200 cm and a vector D between a third and a fourth crane connection element has a length of at least 200 cm.

8. Wind turbine tower according to claim 7, wherein the angle between the vectors A and B is greater than the angle between the vectors C and D, but in that the length of the vectors A and C is the same and in that the length of the vectors B and D is the same.

9. Wind turbine tower according to claim 6 wherein said at least three crane connection elements of the second tower section are arranged on essentially the same plane.

10. Wind turbine tower according to claim 6, wherein the vertical distance between any three of said at least three crane connection elements of the second tower section is less than 50 cm.

11. A crane comprising a base portion, two arms displaceably connected to the base portion and a lifting boom displaceably connected to the base portion, said lifting boom being provided with a lifting wire and a lifting member, for lifting a load, wherein a. the two arms and the base portion in combination comprise at least three tower flange connection elements arranged to be detachably connectable to cooperating crane connection elements on a flange of a wind turbine tower section, b. each arm comprises one of the tower flange connection elements, and c. the vertical distance between any two tower flange connection elements in the normal operating position of the crane is less than 1 m, less than 50 cm or less than 25 cm.

12. A crane according to claim 11, wherein the crane comprises four tower flange connection elements and in that each of the two arms comprises two tower flange connection elements.

13. A crane according to claim 11, wherein the crane comprises four tower flange connection elements and in that the crane comprises four arms, each arm comprising one of the four tower flange connection elements.

14. A crane according to claim 11, wherein the vertical distance between any three of the at least three tower flange connection elements is less than 50 cm or less than 25 cm.

15. A crane according to claim 11, wherein said at least three tower flange connection elements are arranged on essentially the same horizontal plane.

16. A crane according to claim 13, wherein the four tower flange connection elements are arranged on essentially the same horizontal plane.

17. A crane according to claim 11, wherein the crane further comprises a wire and pulley system comprising the lifting wire and the lifting member.

18. A crane according to claim 17, wherein the wire and pulley system comprises a lower pulley block comprising a pulley and an upper pulley block comprising at least one more pulley than the lower pulley block, the upper pulley block comprising the lifting member and the lower pulley block comprising a first connection element suitable for establishing a detachable connection to the lifting member and a second connection element suitable for establishing a detachable connection to a crane hoisting connection element arranged on a tower section of a wind turbine tower when the crane is connected to a tower section.

19. A crane according to claim 11, wherein the crane further comprises a moment compensating mechanism comprising a moment compensating arm which is at least 300 cm long and which extends out from the crane with a horizontal component, the end of said arm being connected via a wire to a winch located remotely from the crane.

20. A crane according to claim 11, wherein the length of the lifting boom is such that the vertical distance between the highest location of the lifting member and the tower flange connection elements is greater than 5 m, greater than 10 m or greater than 20 m.

21. A crane according to claim 20, wherein said vertical distance is greater than the height of a tower section.

22. An assembly comprising: a wind turbine tower according to claim 1; a crane comprising a base portion, two arms displaceably connected to the base portion and a lifting boom displaceably connected to the base portion, said lifting boom being provided with a lifting wire and a lifting member, for lifting a load, wherein a. the two arms and the base portion in combination comprise at least three tower flange connection elements arranged to be detachably connectable to cooperating crane connection elements on a flange of a wind turbine tower section, b. each arm comprises one of the tower flange connection elements, and c. the vertical distance between any two tower flange connection elements in the normal operating position of the crane is less than 1 m, less 50 cm or less than 25 cm, said crane being connected to a flange of a tower section of the wind turbine tower; and a winch located near the base of the wind turbine tower, said winch comprising a wire which is connected to the wire and pulley system of the crane.

23. A method of assembling a wind turbine tower comprising the following steps in this order: a. attaching a tower connection section of a crane to a crane connection element on a tower section, b. providing a lifting boom, an upper pulley block, a lower pulley block and a lifting wire, said lifting wire being arranged to go from a location below the crane up to and over the lower pulley block, down and around a pulley fastened on the crane, up and around a pulley on the top of the crane, down and around the upper pulley block and up to the top of the crane, c. lowering the upper pulley block of the crane, d. attaching the upper pulley block to the lower pulley block, e. lifting the lower pulley block by tightening the lifting wire which lifts the upper pulley block, f. attaching the lower pulley block to a connection element on a tower section, g. releasing the upper pulley block from the lower pulley block, h. tightening the lifting wire until the crane is supported by the lifting wire, i. releasing the tower connection section of the crane from the crane connection element on the tower section, j. further tightening the lifting wire to lift the crane up along the tower section, and k. fastening the tower connection section of the crane to an upper crane connection element on the tower section.

24. A method according to claim 23, wherein the method further comprises the steps of providing at least one pulley on the lower pulley block and providing a number of pulleys on the upper pulley block which is greater than the number of pulleys on the lower pulley block.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIGS. 1a+1b show a side view and a perspective view respectively of a first step in a tower building process using the crane and tower according to the current invention.

[0050] FIGS. 2a+2b show a side view and a perspective view respectively of a second step in a tower building process using the crane and tower according to the current invention.

[0051] FIGS. 3a+3b show a side view and a perspective view respectively of a third step in a tower building process using the crane and tower according to the current invention.

[0052] FIGS. 4a+4b show a side view and a perspective view respectively of a fourth step in a tower building process using the crane and tower according to the current invention.

[0053] FIGS. 5a+5b show a side view and a perspective view respectively of a fifth step in a tower building process using the crane and tower according to the current invention.

[0054] FIGS. 6a+6b show a side view and a perspective view respectively of a sixth step in a tower building process using the crane and tower according to the current invention.

[0055] FIGS. 7a+7b show a side view and a perspective view respectively of a seventh step in a tower building process using the crane and tower according to the current invention.

[0056] FIGS. 8a+8b show a side view and a perspective view respectively of an eighth step in a tower building process using the crane and tower according to the current invention.

[0057] FIGS. 9a+9b show a side view and a perspective view respectively of a ninth step in a tower building process using the crane and tower according to the current invention.

[0058] FIGS. 10a+10b show a side view and a perspective view respectively of a tenth step in a tower building process using the crane and tower according to the current invention.

[0059] FIGS. 11a+11b show a front view and a front perspective view respectively of an eleventh step in a tower building process using the crane and tower according to the current invention.

[0060] FIGS. 12a+12b show a front view and a front perspective view respectively of an alternative eleventh step in a tower building process using the crane and tower according to the current invention.

[0061] FIGS. 13a+13b show a rear view and a rear perspective view respectively of the alternative eleventh step shown in FIGS. 12a+12b.

[0062] FIGS. 14a and 14b show a schematic representation of an alternative mounting flange arrangement located at an upper and lower section respectively of the tower.

[0063] FIGS. 15a and 15b schematically show two positions of the wire and pulley system.

[0064] In the following, the invention will be described in greater detail with reference to embodiments shown by the enclosed figures. It should be emphasized that the embodiments shown are used for example purposes only and should not be used to limit the scope of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0065] FIGS. 1a to 11b show eleven steps of a method for assembling a wind turbine tower, placing the nacelle on the top of the tower and mounting the blades to the nacelle. The method used in the figures makes use of a novel type of crane and a tower section with a novel flange to enable the assembly method.

[0066] The function of the crane and the flange will be described with reference to the method steps to better illustrate the function.

[0067] In FIG. 1a+1b, a base tower section 1 has been erected on a supporting surface (not shown), in a manner which is known in the art. The base tower section is typically bolted to a foundation element (not shown) as is known in the art.

[0068] Once the base tower section is erected, a crane 2 is connected to the base tower section 1. The crane comprises a base portion 4, and two arms 6, 8 pivotably connected to the base portion. The two arms are arranged to pivot around a vertical axis so that they can be pivoted into connection with the tower section as shown in FIGS. 1a and 1b or pivoted away from the tower section as shown in FIGS. 5a and 5b.

[0069] In the current embodiment, the arms each comprise two tower flange connection elements 10 which engage with crane connection elements 12 on the tower section. In this embodiment, the crane connection elements 12 are arranged as flanges which extend outwardly from the outer surface of the tower section and the tower flange connection elements 10 are arranged as slots in the arms which engage with the tower flanges 12. A pin 13 is inserted into a hole 14 in an upper surface of the crane arms to engage with a corresponding hole 16 in the crane connection element flanges 12 on the tower section. It should be noted that this is one embodiment of a crane connection element and a tower flange connection element and it is shown rather schematically. It should be clear to the person skilled in the art, that the crane connection elements on the tower section and the tower connection elements on the crane can be formed in many different ways. Furthermore, automatic solutions with hydraulic or electrically operated locking mechanisms could be imagined.

[0070] In this embodiment, the base tower section 1 has two sets of crane connection elements 12. A first set located near the middle 18 of the base tower section and a second set located at the upper end 20 of the base tower section. In the first step, the crane is attached to the first set of crane connection elements so that the crane does not have to be lifted so high. The crane can be transported to the site via a truck and then lifted into place via a separate crane, or by lifting itself from the truck. This process is not illustrated as the person skilled in the art could provide a suitable way of getting the crane from the truck to the lower most crane connection elements.

[0071] The crane connection elements 12 shown in the figures, are arranged as steel flanges which extend outwardly from the outer surface of the tower section. In the case where the flanges are arranged at the upper portion of the tower section, the flanges can be an integrated part of the bolt flange which is used to bolt two tower sections together. Such bolt flanges are integrated into the end of the tower sections already and the crane connection flanges can be provided by extending the bolt flange outwardly past the outer surface of the tower section.

[0072] The base portion 4 and arms 6,8 of the crane are arranged such that when the arms are both connected to the crane connection elements 12 of the tower section 1, then the base portion can absorb a large moment about the crane connection elements in a safe manner and without undesired deflection. Hence, the entire load of the crane can be supported by that arms and the base portion. The term “large moment” should be related to the crane size and the maximum amount that the crane is designed to lift. Larger cranes which can lift larger tower sections will have to have stronger arms and stronger crane connection elements need to be provided on the tower sections. Smaller cranes which lift smaller tower sections can be made with less strong arms and less strong crane connection elements can be provided on the tower sections. The person skilled in the art will be able to determine the necessary strengths and sizes to ensure a safe operation of this crane type.

[0073] The crane further comprises a lifting boom 22 connected to the base portion 4. The lifting boom is arranged to be able to tilt about a horizontal axis at the connection to the base portion and also pivot about a vertical axis passing through the base portion. The details of the crane tilt and pivot mechanism are not shown in detail. In general, the details of the crane are shown schematically to illustrate the novel concepts of the invention. However, suitable lifting booms are known in the art which could be used in this application. The actual implementation could be different than that shown in the figures. The person skilled in the art can however provide the details necessary to implement the solution based on his or her common general knowledge of lifting booms.

[0074] The crane also comprises a wire and pulley system comprising a lifting wire and a number of pulleys. The wire and pulley system has two purposes. The first purpose is to act as a lifting wire to lift loads with the crane via the lifting hook 30. The second purpose is to lift the crane itself so that it can move up and down the tower. The wire and pulley system will be described in more detail with regards to the schematic FIGS. 15a and 15b. In the FIGS. 1a-11b, the details of the wire and pulley system are not shown in detail as they would just complicate the figures. However, in some of the FIGS. 1a-11b, a thick grey line is provided to schematically illustrate how the main wire 32 of the wire and pulley system could be routed. The wire is shown overly simplified to illustrate the concept. In a real world system, additional details will be provided to ensure safety, strength and function. The person skilled in the art will understand the concept of the current invention and together with the more schematic illustrations in FIGS. 15a and 15b, be able to provide a wire and pulley system which fulfils the demands for a real world system.

[0075] The main lifting wire is controlled via a winch 34 located on the ground, close to the base of the tower. The winch has not been shown, but its location is shown with the reference numeral 34. Hence, the crane itself does not have to comprise a lifting winch and does not have to be provided with power to lift the crane or the tower sections. The entire operation and power supply can remain on the ground. The power supply and the winch can therefore also function as a part of the counterweight for the lifting operations. Instead of having to lift a counterweight to the top of the crane, the counterweight can remain on the ground.

[0076] FIGS. 2a+2b show a second step in the assembly procedure. In this step, the main lifting wire 32 has been slacked out so that the lifting hook 30 (hidden by the arm) is lowered until it comes into contact with a crane lifting block 36 (also hidden by the arm). The crane lifting block is attached to the tower section near the crane connection elements via a crane hoisting connection element 38. This is partially hidden in FIG. 2a by one of the arms. The lifting hook is connected to the crane lifting block and then the crane lifting block is detached from the crane hoisting connection element.

[0077] The wire is then tightened up as shown in FIGS. 3a and 3b. As the wire is tightened up the crane lifting block 36 will be raised until it is at the same height as a crane hoisting connection element 38 located near the top of the tower section. The crane lifting block 36 is then connected to the crane hoisting connection element at the top of the tower section.

[0078] The lifting hook is then detached from the crane lifting block 36 and the wire is further tightened to move the lifting hook all the way to the top of the lifting boom. This is shown in FIGS. 4a and 4b.

[0079] Once the wire is all tightened, then the arms are folded out to release the crane connection elements on the tower section. This is shown in FIGS. 5a and 5b. The crane is now hanging from the crane lifting block 36 attached to the tower section via the crane hoisting connection element 38.

[0080] The wire is then tightened even further as shown in FIGS. 6a and 6b to lift the crane up the tower. In order to prevent damage to the tower as the crane moves up the tower, a lower support arm 40 is provided on the crane with rollers 42 which engage with the tower surface allowing the crane to roll up the side of the tower section.

[0081] When the crane arrives at the upper portion of the tower, and the arms are at the same level as the crane connection elements 12 at the upper end of the tower, then the arms are pivoted in again and the tower flange connection elements of the arms engage with the crane connection elements of the tower section. This is shown in FIGS. 7a and 7b. The crane has now been moved to the top of the tower section and is again firmly connected to the tower section via the crane connection elements 12. The crane is now ready to lift the next tower section into place.

[0082] FIGS. 8a and 8b show how the cranes lifting boom has been tilted about a horizontal axis to extend over the base tower section so that it is in position to lift the next tower section 44 into place. In this case, as is evident from FIG. 8a, the next tower section exerts a relatively high load on the lifting boom of the crane. This generates a large moment on the base portion of the crane and is illustrated by the arrow X in the figure. This moment is absorbed by the arms of the crane and transferred to the tower flange via the crane connection elements 12 on the tower section.

[0083] Furthermore, as illustrated in FIG. 8a, the crane in this embodiment also comprises an extra moment compensating arm 46 extending from the base portion of the crane. The main lifting wire 32 is passed over this arm and due to the distance Y between the wire attachment point and the base portion of the crane, the wire itself together with the arm will generate a counter moment Z which helps to balance the moment X about the base portion of the crane. In this way, the actual moment transferred to the tower flange can be reduced.

[0084] The moment compensating arm 46 can furthermore be rotated about a horizontal axis such that the horizontal distance Y between the base portion and the wire attachment portion of the arm can be adjusted. In this way, the moment provided by the moment compensating arm can also be adjusted, even though it is not possible to adjust the actual tension in the lifting wire 32.

[0085] As will be described in more detail later on with respect to FIGS. 12a-13b, the arm can also be rotated about a vertical axis to adjust the direction of the moment compensation. This is relevant when the crane lifting boom also rotates about a vertical axis as will be shown in relation to FIGS. 12a-13b.

[0086] FIGS. 9a and 9b show how the upper tower section has been installed on top of the base tower section. Once the upper tower section is in place, then the upper tower section and base tower section can be bolted together as is known in the art. This is not described in more detail here.

[0087] Once the upper tower section is bolted into place, then the crane can release the upper tower section and restart the crane lifting procedure as illustrated in FIGS. 2a and 2b. The process can be repeated until the entire tower is built.

[0088] Once the entire tower is built and the crane is installed on the uppermost tower section 48, the crane can then lift the nacelle 50 into place, as shown in FIGS. 10a and 10b. Likewise, after the nacelle is in place, then the crane can lift the blades 52 into place as shown in FIGS. 11a and 11b.

[0089] Once the blades are in place, then the crane can lower itself down by performing the procedure described in FIGS. 11a-11b in reverse.

[0090] Should an existing wind turbine need to be repaired, then a similar procedure could be used to hoist the crane to the top of the wind turbine tower after which it can be used to exchange blades, turbines, generators, drives, etc. . . .

[0091] FIGS. 12a to 13b show additional details of how the moment compensation arm 46 can be rotated about a vertical axis to better compensate for the moments during the lifting operation. When comparing FIGS. 11a and 12a, it can be seen that in FIG. 11a the load from the blade, is arranged on the left side of the tower. The moment compensating arm 46 is also located on the left side of the tower. The moment compensating arm 46 therefore increases the moment applied to the tower flange. However, in FIGS. 12a and 13a, the moment compensating arm has been rotated about the vertical axis so that it extends to the right of the tower. In this way, the moments are better balanced.

[0092] In another embodiment (not shown), the moment arm could be in a fixed position relative to the lifting boom of the crane. As the lifting boom rotates, the moment arm would also rotate the same amount. In this way, the moments would always be balanced without requiring additional control of the position of the moment arm. This arrangement would also ensure that the wires would have less chance to tangle or wrap around each other.

[0093] FIGS. 14a and 14b illustrate another schematic illustration of a crane attachment mechanism. In this case, instead of four connection elements, only three connection elements 100 are provided on the tower section and on the crane. The base portion 102 itself connects to one of the connection elements on the tower section and then each arm 104 connects to an additional connection element 100. This illustration has been provided very schematically to illustrate a solution with only three points. It is maintained that the person skilled in the art will be able to implement this in a real life situation without undue burden.

[0094] FIGS. 14a and 14b also schematically illustrate another option for the arrangement of the crane connection elements on the tower sections. Since towers taper from the bottom to the top, as the crane moves up the tower, the diameter of the tower sections will get smaller. In FIG. 14b, the diameter is larger than in FIG. 14a. This illustrates the difference between a lower section (14b) and a higher section (14a). However, even though the locations of the crane connection elements on the circumference change as the crane moves up the tower, crane connection elements are arranged such that the distance between the elements and the position of the elements on the tower section are adjusted so that the arms of the crane can clamp onto different flanges without having an excess of tower flange connection elements. In the figure, it can be seen that the length X of the arm between the pivot point and the connection element does not change. However, the diameter of the tower section, and the angle between the crane connection elements changes as can be seen by comparing the angle between the dashed lines in the figures. In this way, the same tower connection elements of the arms of the crane can be used all the way up the crane.

[0095] FIGS. 15a and 15b schematically illustrate the wire and pulley system used in the crane. FIG. 15a is roughly equivalent to a position between FIGS. 2a and 3a where the crane lifting block 36 has been lifted half of the way to the top and FIG. 15b is roughly equivalent to FIG. 6a/6b.

[0096] The figures show a portion of a tower section 1 to the right of the figures. A crane hoisting connection element 38 is also shown attached to the tower section 1. The wire and pulley system of the crane comprises a crane lifting block (lower pulley block) 36 and a lifting block (upper pulley block) 30. The lifting block 30 has in this embodiment two pulleys and the crane lifting block 36 only has one pulley. In this way, when the two pulley blocks are connected together and tension is applied to the wire, then the two blocks will move upwardly. When the connection between the blocks is broken, then as tension is applied to the wire, the lifting block 30 will move upwardly and the crane lifting block 36 will move downwardly. In FIG. 15b, the crane lifting block is attached to the tower and therefore, the crane lifting block is fixed in position with respect to the tower. As such, as tension is applied to the wire, the crane will be lifted up. Due to this wire and pulley system, a single wire 32 from the base of the tower can control the entire operation of the crane. This covers both the lifting of the crane itself and the loads lifted by the crane when installed.

[0097] As can be seen from the figure, the lifting wire 32 is pulled at the lower end of the figure by a tension T provided by a winch which in the current embodiment is located on the ground. The lifting wire runs up to the pulley 36a on the lower pulley block 36, then down to a lower pulley 37, then up to an upper pulley 39 and then back down to the pulleys 30a and 30b on the upper pulley block 30 before ending at the lifting boom. This is a very simplified arrangement to illustrate the operating principle. In the real world, additional pulleys and wires will be provided as will be known to the person skilled in the art.

[0098] It is to be noted that the figures and the above description have shown the example embodiments in a simple and schematic manner. Many of the specific mechanical details have not been shown since the person skilled in the art should be familiar with these details and they would just unnecessarily complicate this description. For example, the specific materials used, the specific actuators used and the specific construction of the crane itself have not been described in detail since it is maintained that the person skilled in the art would be able to find suitable materials and suitable processes to manufacture the systems according to the current invention.