Kite System

Abstract

The present invention relates to a kite system comprising a kite (14), a line tree (24), a gondola (25) and a towing rope (15). The kite (14) is connected to the gondola (25) via the line tree (24), the towing rope (15) extending between the gondola (25) and an attachment point (16, 55) installed on the ground. The pulling force exerted by the kite (14) during operation is transmitted through a towing section (15, 24) which extends from the kite (14) to the attachment point (16, 55) via the line tree (24) and the towing rope (15). A separation device (40) is arranged in the towing section (15, 24) which is released on contact with water. The present invention further relates to a separation device (40) suitable for a kite system.

Description

[Technical field]

[0001] The present invention relates to a kite system comprising a kite, a line arrangement, a pod and a tension rope, the kite being connected to the pod via the line arrangement, the tension rope running between the pod and a ground attachment point.

[0002] By suitable adjustment of the aerodynamic characteristics, the kite can be made to move along a flight path aligned substantially perpendicular to the tension ropes. During the movement of the kite along the flight path, tension is exerted on the tension ropes. The tension can be used, for example, to generate electrical energy or as propulsion for a watercraft.

[0003] Particularly when used on ships or in offshore power generation situations, kites may accidentally land in the water. Tension ropes stretched across the sea between the attachment point and the kite may be dangerous for the ship. Reeling in and retrieving a kite that is drifting in the water may be more difficult as the water may generate significant forces on the kite as it stretches open. Furthermore, equipment may be damaged if large forces are transmitted to the attachment point via the tension ropes.

[0004] The object underlying the present invention is to provide a kite system in which the risks associated with kites accidentally landing in water are reduced. Proceeding from the aforementioned prior art, this object is achieved by the features of the independent claims. Preferred embodiments are specified in the dependent claims.

[0005] In the kite system according to the invention, the tension exerted by the kite is transmitted via a tension strand, which extends from the kite to the attachment point via a line arrangement and a tension rope, in which a separation device is arranged, which is triggered on contact with water, and which is an element of the tension strand, through which the tension acting between the kite and the attachment point is transmitted completely or partly.

[0006] The invention is based on the idea of ​​reducing the tensions resulting from a kite drifting in water by decoupling the strand elements involved in the transmission of tension forces in the tension strand. Landing a kite in water is an event that is not envisaged in the normal operation of a kite system, and for this reason it cannot be assumed that all control mechanisms provided for the normal operation of the kite system are still operational. In the invention it is proposed to configure the decoupling device to be triggered by contact with water. This ensures that the decoupling of the connections in the tension strand still works reliably even if other control devices fail.

[0007] An attachment point is ground if it is not lifted off the ground by the tension of the kite. A ground attachment point can be rigidly connected to the ground. For example, it could be a ground attachment point on a vessel, floating pontoon, or land-based mobile system.

[0008] The tension strand extending between the kite and the attachment point may include a first portion in which tension is transferred via a plurality of mutually parallel strand elements. This portion of the tension strand may correspond to a line arrangement extending between the kite and the pod. The separation device may be disposed in one of the several mutually parallel strand elements. In this embodiment, even after triggering of the separation device, there is still a connection between the kite and the attachment point via the remaining strand elements, through which tension may be transferred.

[0009] The tension strand can be bifurcated into several parallel strand elements between the separation device and the kite, so that there are several points on the kite where no tension forces are acting any more after triggering of the separation device. It is also possible for the kite system to comprise several separation devices arranged parallel to one another in the tension strand. In particular, it is possible to separate all strand elements of a first part so that there is no longer any connection to the second part of the tension strand.

[0010] The tension strand may include a second portion in which the entire tension is transferred through a single strand element. The second portion of the tension strand may correspond to a tension rope extending between the pod and the attachment point. A separation device may be disposed in the second portion of the tension strand to ensure that the connection between the kite and the attachment point is completely interrupted upon triggering of the separation device.

[0011] The separation device arranged on the tension rope may have a position adjacent to the pod. In particular, the distance between the pod and the separation device may be less than 20%, preferably less than 10%, and even more preferably less than 2% of the length of the tension rope when it is fully unwound. After triggering of such a separation device, the tension rope can be retracted without significant resistance. The kite has to be retrieved in a separate operation, for example by sailing a vessel towards the kite while it is drifting freely in the water and retracting it on board the vessel.

[0012] On the other hand, if the triggering of the separating device only partially separates the tension strand, this opens up the possibility of pulling the kite together with the tension rope to the attachment point. For this purpose, it is preferred if the triggering of the separating device puts the kite in a state where it can be pulled through the water without significant hindrance.

[0013] In normal operation of the kite system, the tension strand is configured so that the kite covers a large area transverse to the tension direction. This is achieved by attaching the line arrangement to the kite at multiple points that generate a large surface in a plane aligned perpendicular to the tension direction. The kite system may be configured so that the points of the kite that are still attached to the tension strand generate a surface perpendicular to the tension direction, the surface still corresponding to up to 50%, preferably up to 20%, more preferably up to 10% of the surface generated in normal operation.

[0014] The kite can extend transversely to the direction of travel from a first edge through a central portion to a second edge. The kite system can be configured such that when a separation device is triggered, the strand elements extending to the first edge and the second edge are detached. The tension strand is then connected only to the central portion of the kite. The peripheral portions can move backwards when the kite is pulled through the water.

[0015] Alternatively, the kite system may be configured such that after triggering of the separation device, only one edge of the kite remains connected to the tension strand, and the strand elements extending to the opposite edge and the central portion are separated. The edge of the kite that is still connected to the tension strand may be the laterally peripheral portion, the longitudinal front portion, or the longitudinal rear portion. The longitudinal direction refers to the direction parallel to the direction of travel of the kite, i.e. generally parallel to the kite wing cross-sectional shape.

[0016] The separation device may include a locking mechanism that allows the separation device to be changed between a closed state and an open state. In the closed state, tension may be transmitted through the separation device disposed on the tension strand. In the open state of the separation device, the tension strand is separated in this position.

[0017] The separation device may comprise a trigger element that responds to contact with water. The trigger element may be in mechanical contact with the locking mechanism, which ensures that the separation device is maintained in the closed state until the trigger element contacts water. For example, the trigger element may have a body made of a water-soluble material that dissolves on contact with water, thus opening an actuation path for the locking mechanism. The body may be, for example, cellulose pellets or salt pellets. The locking mechanism may be spring-loaded, which ensures that the locking mechanism automatically changes to the open state after the actuation path is opened.

[0018] It is also possible for the trigger element to be configured as a trigger sensor that emits a control signal upon contact with water. The control signal may be transmitted to the locking mechanism via a cable or wireless link. After receiving the control signal, the locking mechanism may be actuated such that the separation device changes from a closed state to an open state. Also included are embodiments in which the locking mechanism is actuated in some other way, for example pneumatically or hydraulically.

[0019] The separation device may be configured to be able to change between an open state and a closed state while bypassing the trigger element. In particular, the separation device may have a locking mechanism that can be actuated without triggering the trigger element. This allows the separation device to be used, for example, to establish or separate a connection between a line arrangement and a pod or between a pod and a tension rope. The trigger element may be retained unchanged and may retain the ability to trigger on contact with water.

[0020] The actuator may be spring-loaded to maintain the separation device in a closed state. The spring force maintaining the actuator may be selected such that it can be manually overcome.

[0021] In one embodiment, the separation device is a shackle that opens automatically after triggering of the trigger element. Alternatively, separation devices designed to separate the tension strand or parts thereof by mechanical action, for example by cutting, are also possible. In one embodiment, the separation device is a pyrocutter. Separation devices acting on parts of the tension strand by combustion or explosion are also possible.

[0022] The trigger element may be configured to only react on contact with salt water and not on contact with fresh water. This may be useful when the kite is operating at sea, where a kite collision may result in contact with salt water. In contrast, contact with rain water will not lead to the triggering of the trigger element.

[0023] Additionally or alternatively, the separation device may be configured such that the trigger element is protected from rainwater, for example the trigger element may be covered at the top or only accessible from the outside via a channel, which ensures that the trigger element is only triggered after immersion in water.

[0024] A separation device having one or more of the mentioned features has independent inventive subject matter even if it is not used in the context of the kite system according to the invention.

[0025] The kite system may also comprise a ground attachment point from which the tension rope extends. The ground attachment point may be part of a floating structure on the sea, for example of a floating pontoon or of a vessel. The kite system may be an element of an apparatus for generating electric energy. The apparatus may comprise a generator driven via a tension rope winch. The kite system may also be connected to an attachment point on a vessel, which allows the kite system to be used to generate propulsion for the vessel.

[0026] The invention is described below by way of example only with reference to preferred embodiments and with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 shows a device for generating electrical energy comprising a kite system according to the invention. [Diagram 2] FIG. 2 is a schematic diagram of the device of FIG. 1 in operation; [Diagram 3] FIG. 2 is an enlarged view of a detail of the kite system of FIG. 1. [Figure 4] FIG. 2 is another enlarged view of the details of the kite system of FIG. 1. [Diagram 5] FIG. 1 shows a kite system according to the present invention. [Figure 6] 1 shows an alternative embodiment of a kite system according to the present invention; [Figure 7] FIG. 7 shows the kite system of FIG. 6 in another state. [Figure 8] FIG. 1 shows another embodiment of a kite system according to the invention. [Figure 9] FIG. 9 shows the kite system of FIG. 8 in another state. [Figure 10] FIG. 2 shows an embodiment of a separation device for a kite system according to the invention. [Figure 11] FIG. 1 shows a watercraft having a kite system according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The device shown in Fig. 1 for generating electrical energy comprises a kite system 23 according to the invention connected via a tension rope 15 to a tension rope winch 16, which forms an attachment point in the sense of the invention. The kite system 23 comprises a kite 14 connected via a line arrangement 24 to a pod 25.

[0029] A power generating / work performing machine 17, operating as a generator in a first operating state and as a motor in a second operating state, is coupled to the tension rope winch 16. The power generating / work performing machine is linked to the public power grid 19 via a power line 18 comprising a frequency converter and a transformer, thus making it possible either to feed the electric energy generated by the power generating / work performing machine 17 to the power grid 19 or to operate the power generating / work performing machine 17 as a motor using electric energy taken from the power grid 19. The device comprises a control unit 20 designed to control the interaction between the components of the device.

[0030] The tension rope winch 16, together with components of the power generating / work performing machine 17 and power lines 18, are disposed on a floating pontoon 12 floating on the ocean 11. The floating pontoon 12 is connected to an anchorage 10 located on the ocean bed 13.

[0031] The control unit 20 comprises an antenna 21, thus enabling control signals to be exchanged with the pod 25 via a wireless link 22. In particular, the control unit 20 sends control signals to the pod 25 for controlling the flight path of the kite 14. Using the control signals, the lengths of the control lines of the line arrangement 24 are altered, thereby influencing the flight direction of the kite 14.

[0032] In the exemplary embodiment shown in FIG. 2, the kite 14 is guided along a figure of eight aligned substantially transversely to the wind direction W. While the kite 14 follows its flight path, tension is exerted on the tension rope 15, which drives the power generation / work execution machine 17 via the tension rope winch 16. By the power generation / work execution machine 17 operating as a generator in this operating state, the mechanical energy is converted into electrical energy and fed via the power line 18 to the public grid 19. It is also possible to store part of the generated energy in the form of electricity in an energy storage device in the power line 18. This makes it possible to generate electrical energy until the length of the tension rope 15 runs out and the tension rope 15 is fully unwound from the tension rope winch 16. The tension rope 15 is then retracted by the power generation / work execution machine 17 operating as a motor before electrical energy can be generated again.

[0033] According to Fig. 3, the line arrangement 24 of the kite system 23 according to the invention comprises an active control line 26, a passive control line 27 and a fixed line 28, each attached to a pod 25 and branching from a node 29 into ends attached to the kite 14. The fixed line 28 extends from an end fixedly connected to the pod 25 to the central part of the kite 14. The active control line 26, whose length is adjustable, extends from the pod 25 to the two peripheral parts of the kite 14. The passive control line 27, deflected by a pulley 30 at the pod 25, is fixed to the kite 14 between the fixed line 28 and the active control line 26.

[0034] By adjusting the length of the active control line 26 it is possible to control the direction of movement of the kite 14. As the active control line 26 is adjusted, the passive control line 27 is led through the pulley 30 and the length of the passive control line 27 from the kite 14 through the pulley 30 and back to the kite 14 remains unchanged.

[0035] The kite 14 forms an airfoil section extending longitudinally from a tip 31, visible in Fig. 3, to an aft end, not visible in Fig. 3, via an outer surface 32 and an inner surface 33. A cavity is formed inside the kite 14, said cavity being under overpressure during normal operation of the kite system. The kite 14 includes an opening 34 formed in the tip 31, through which air can enter the interior, and overpressure is built up when the kite 14 is in motion.

[0036] According to FIG. 5, the pod 25 is connected to the tension rope 15 via a separation device 40. The separation device 40 is triggered on contact with the water 40 and separates the connection between the pod 25 and the tension rope 15. If the kite 14 falls into the sea 11 due to abnormal operating conditions, the separation device 40 contacts the sea water and the connection between the pod 25 and the tension rope 15 is released. The tension rope 15 can be retracted by the tension rope winch 16 without the need to apply a relatively large force. This has the advantage that a danger to the vessel, which may result from the tension rope 15 being stretched between the tension rope winch 16 and the pod 25, can be quickly removed. After triggering of the separation device 40, the kite 14 and the pod 15 drift freely on the sea and can be retrieved by the vessel.

[0037] Figure 10 shows an embodiment of a separation device 40 according to the invention in the form of a shackle. The shackle comprises a shackle body 41 designed as a casting. A closure piece 43 is connected to the front end of the shackle body 41 via an articulated connection 42, said closure piece being maintained in the closed position shown in Figure 10 by a latch 44. An eye 45 is screwed into the shackle body 41 at the opposite rear end of the shackle. During operation of the kite system 23 shown in Figure 5, the tension rope 15 is connected to the eye 45 and the front end of the shackle is attached to the pod 25.

[0038] The shackle includes a retaining element 46, which maintains the latch 44 in a closed position. The retaining element 46 is disposed in a hole in the shackle body 41 and is maintained in the forward position shown in Figure 10 by a retaining spring 47. The hole is closed by a plug 48. The retaining spring 47 is supported on the front end of the plug 48 via a cellulose pellet 49.

[0039] If the shackle falls into the sea 11, the cellulose pellets 49 come into contact with seawater and dissolve. The retaining element 46 is no longer supported on the plug 48, thus opening up space for the movement of the latch 44. The latch 44 is released by the force of the latch spring 50, which is under stress in normal conditions. The closure piece 43 opens and the pod 25 is separated from the tension rope 15.

[0040] The space in which the cellulose pellets 49 are placed is connected to the environment by a first channel 51 formed in the plug 48 and a second channel 52 formed in the closure body 41. Seawater can enter through one of the channels and air can escape through the other channel. The entrapment of air bubbles is avoided. The channels 51, 52 are configured and aligned such that rainwater cannot reach the cellulose pellets 49 during normal operation of the kite system 23. Only after the shackle is immersed in water does the cellulose pellets 49 dissolve.

[0041] If an operator applies pressure to the latch 44 via the gripping surface 53, it is also possible for the shackle to be opened without dissolving the cellulose pellets 49. The retaining spring 47 is dimensioned so that it can be compressed by manual force.

[0042] In FIG. 6 the line arrangement 24 is shown in a simplified form with three fixed lines 28 that extend to the central part of the kite 14 and three control lines 26 that extend in each case to the opposite edge of the kite 14. The kite system comprises a total of three separation devices 40, two of the three fixed lines 28 being attached to the pod 25 via a first separation device 40 and two of the three control lines 26 being attached to the pod via a second and a third separation device 40, respectively. If the kite 14 falls into the sea 11, the three separation devices 40 are triggered, so that only one of the fixed lines 28 and in each case only one of the control lines 26 is still connected to the pod 25. This connection is with the front part of the airfoil profile of the kite 14, while the rear part of the kite 14 can rotate backwards and outwards. In this state, the kite 14 forms a flat structure which can be pulled in by the tension ropes 15 without the need to exert a large force (see figure 7).

[0043] Figures 8 and 9 show an alternative embodiment in which two separation devices 40 are arranged on the line arrangement 24, which is shown in a simplified manner. The first separation device 40 separates all three fixed lines 28 from the pod 25. The second separation device completely separates the set of control lines 26 arranged on one side of the fixed lines 28 from the pod, so that the kite 14 is connected to the pod 25 only via the other set of control lines 26. After triggering of the separation device 40, a flat structure is formed as well, which can be pulled into the water without a large expenditure of force and can be retracted by the tension ropes 15 (see Figure 9).

[0044] 11 shows an alternative embodiment of the invention, in which a kite system 23 according to the invention is used to generate propulsion for a vessel 54. The tension ropes 15 are attached to attachment points 55 on the vessel 54.

Claims

1. A kite system comprising a kite (14), a line arrangement (24), a pod (25) and a tension rope (15), the kite (14) being connected to the pod (25) via the line arrangement (24), the tension rope (15) extending between the pod (25) and a ground attachment point (16, 55), the tension exerted by the kite (14) during operation being transmitted via a tension strand (15, 24) extending from the kite (14) to the attachment point (16, 55) via the line arrangement (24) and the tension rope (15), and a separation device (40) is arranged on the tension strand (15, 24) which is triggered on contact with water.

2. 2. A kite system according to claim 1, characterized in that the tension strands (15, 24) are completely separated when the separation device (40) is triggered.

3. 3. A kite system according to claim 1 or 2, characterized in that the tension strand (15, 24) comprises a portion in which the tension is transmitted via a number of mutually parallel strand elements (26, 27, 28).

4. 4. A kite system according to claim 3, characterized in that the separation device (40) is arranged in one of several mutually parallel strand elements (26, 27, 28).

5. 5. A kite system according to claim 3 or 4, characterised by a plurality of separation devices (40) arranged parallel to one another in the tension strand (15, 24).

6. A kite system according to any one of claims 3 to 5, characterised in that the tension strands (15, 24) are partially detached when the separation device (40) is triggered.

7. 7. A kite system according to claim 6, characterized in that the points of the kite (14) attached to the tension strand after the triggering of the separation device (40) generate a surface perpendicular to the tension direction, said surface still corresponding to a maximum of 50%, preferably a maximum of 20%, even more preferably a maximum of 10% of the surface generated in normal operation.

8. A kite system according to any one of claims 1 to 3, characterized in that the tension strand (15, 24) comprises a portion in which the entire tension is transmitted through a single strand element (15), and in that the separation device (40) is arranged in the single strand element (15).

9. Kite system according to any one of the preceding claims, characterized in that the detachment device (40) comprises a trigger element (49) which dissolves on contact with water.

10. Kite system according to any one of the preceding claims, characterised in that the trigger element (49) is triggered only on contact with salt water.

11. Kite system according to claim 9 or 10, characterized in that the trigger element (49) is protected from contact with rain water.

12. Kite system according to any one of claims 9 to 11, characterised in that the trigger element (49) is in mechanical contact with a locking mechanism (44) of the separation device (40).

13. A kite system according to any one of claims 9 to 12, characterised in that the separation device (40) comprises a locking mechanism which allows actuation of the trigger element (49) without triggering it.

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