EP2746462B1 - Device and method for reducing the sound emissions when driving piles at sea - Google Patents

Description

The invention relates to a device for reducing noise emissions during pile driving at sea to found foundations of offshore wind turbines with multiple fluid nozzles for dispensing gas or gas-containing liquid for generating gas bubbles.

The invention further relates to a method for the reduction of noise emissions during pile driving at sea to establish foundations of offshore wind turbines in the gas bubbles are discharged from at least one, preferably more fluid nozzles in the lake water.

The wind-offshore market today has significant problems to meet the required noise barrier of 160 dB for piling pile driving to found wind turbine foundations.

In known methods, an open bubble curtain is produced at great expense by an air line routed annularly around the construction site around the seabed. From regularly installed openings to each other flows from a compressor on the surface originating compressed air. This bubble curtain, however, is unstable, especially in tidal waters, and thus to Reduction of noise emissions in such waters not readily usable.

Tidal currents at speeds of 1.55 meters per second (about 5.58 km / h) often occur in the affected wind power areas, especially at high tide. Such currents have a disastrous effect on bladder curtains at the existing water depths of 25 to 40 meters.

Therefore, only low noise attenuation of only a few dB was achieved, whereby the output sound intensity during ramming can reach over 180 dB (measured at a distance of 750 meters). The achieved sound attenuation is too low to protect the environment, especially the marine mammals.

The preambles of claims 1 and 15 are from the document EP 16 40 508 A1 known.

Object of the present invention is therefore to provide an apparatus and a method for reducing noise emissions during pile driving at sea for foundations foundations of offshore wind turbines, which allow a more effective and reliable reduction even under difficult weather conditions and / or flow conditions under water.

The invention solves the problem in a first aspect with a device of the type mentioned, which has an insertable under water means for guiding the gas bubbles generated by the fluid nozzles. By means of the device for guiding the gas bubbles, a fine bubble curtain is generated, which dampens the resulting sound effectively. Additionally, the natural minerals and proteins dissolved in the water can also cause foam formation, which further increases the damping properties of the generated bubble curtain. The fluid nozzle or the fluid nozzles are preferably annular. The outer diameter of an annular fluid nozzle is preferably in a range of 5 to 50 meters. In particular, when ramming a bank attachment, however, non-annular geometries may be preferred. The gas is introduced, for example via at least one port in the fluid nozzle (s).

In a first preferred embodiment of the device according to the invention, the device for guiding the gas bubbles has at least one curtain or a guide segment. The fine bubble streams rising from the fluid nozzles adhere, at least temporarily, to the process or guide segment, thereby slowing their ascent to the surface, although a certain proportion also can ascend freely. By adhering to the curtain or on the guide segment air bubbles creates a wall with many air bubbles, which form an insulating bubble curtain against emerging impact noise. In this case, the deviating from the water sound refractive index and the different sound propagation speeds of both media are used. The sound is reflected by the bubble curtain to a large extent and subsequently lose energy. Another part of the sound will suffer significant energy losses as it penetrates the bladder curtain and the curtain or guide segment. The number of curtains and guide segments is not limited to one. A multiplicity of curtains or guide segments can also be used in a device according to the invention.

In a second preferred embodiment of the device according to the invention, the curtain or the guide segment consists of such a material and / or dimensioned such that gas bubbles rising or moving in the water are held up substantially by the curtain or the guide segment, while substantially transversely to the surface the curtain or the guide segment flowing water can at least partially pass through the curtain or the guide segment. On the one hand, this permeability selectivity ensures the bundling, delimiting and guiding of the gas bubbles or gas bubble flow within the curtain or guide segment and, on the other hand, renders the device robust due to the water permeability permitting at least a portion of the water to strike the curtain or guide element Ocean currents, as caused by tides, high winds and / or shipping.

In a further preferred embodiment of the device according to the invention, the curtain has a fabric structure. Alternatively or additionally, in another embodiment, the curtain comprises at least one of the following components: metallic fibers, plastic fibers, fabric fibers, mineral materials, neoprene fabric, plastic film. The fabric structure may comprise, for example, two-layered or multi-layered stretch-resistant and / or warmer reinforcement fabric, optionally with nonwoven material needled on one side, preferably made of PET material. The layers can each be clamped at intervals of 10 cm or more to each other.

Another embodiment of the device according to the invention has a holding frame on which the curtain or the guide segment can be fastened. The holding scaffold is preferably round, but may also have any other functional geometric shape. The holding framework preferably has struts, which further preferably have fluid nozzles. In this embodiment, gas bubbles are also generated by the fluid nozzles of the holding framework, which dampen the sound. In a preferred embodiment, the holding scaffold on joints, designed such that the holding framework or the entire device can be folded.

The device according to the invention is advantageously further developed in that the holding frame is designed such that the curtain or the guide segment extends in the operating state substantially in the vertical direction. Additionally or alternatively, the curtain or the guide segment has a substantially cylindrical shape and / or a plurality of fluid nozzles arranged on the support frame. Particularly preferably, the plurality of fluid nozzles are arranged vertically spaced from each other on the support frame.

In another preferred embodiment of the device according to the invention, the device for guiding the gas bubbles has two curtains or guide segments which are spaced apart from one another, in particular substantially concentrically in the mounted state, the fluid nozzles being arranged relative thereto in such a way that the gas bubbles enter the intermediate space between the two spaced curtains or guide segments can be introduced.

In a further preferred embodiment of the device according to the invention, the fluid nozzles are arranged relative to the concentrically arranged curtains such that the gas bubbles are generated in the space between the two spaced curtains or guide segments, in particular ascend in this.

In a further preferred embodiment of the device according to the invention, the fluid nozzles have a feed channel and a multiplicity of outlet openings communicating with this feed channel. The entirety of the outlet openings preferably forms a screen structure, which ensures the formation of very many air bubbles. Additionally or alternatively, the fluid nozzles are tube-shaped and the outlet openings are arranged along a row on the tube.

In a further preferred embodiment of the device according to the invention, a plurality of fluid nozzles are spaced from each other, in particular vertically spaced from each other. Due to the vertical spacing of a plurality of fluid nozzles, a plurality of, preferably complementary, gas bubble veils can be generated, so that sound resulting from a substantially continuous bubble veil between the seabed and the sea surface can be effectively damped.

The device according to the invention is further developed advantageously in that a plurality of annular fluid nozzles are arranged one above the other and two spaced cylindrical curtains are held by them.

The object underlying the invention is further achieved by a device for reducing the noise emissions during pile driving at sea to found foundations of offshore wind turbines, which has at least one curtain, which is designed to attenuate sound immissions under water, the curtain preferably according to an embodiment described above and / or according to claim 3 and / or 4 is formed.

In a further preferred embodiment of the device according to the invention, the curtain comprises a plurality of web segments, the entirety of the plurality of web segments forming a closed curtain. Preferably, the web segments extend in the mounted state of the device in the vertical direction, d. H. between the seabed and the sea surface. Preferably, portions of the plurality of web segments intersect to form an overlay that substantially prevents the penetration of gas bubbles between the web segments.

A further preferred embodiment of the device according to the invention has one or more buoyancy elements, which are attached to the curtain or the guide segment, wherein a plurality of buoyancy elements can be coupled by coupling members. In substantially cylindrically shaped curtains or guide segments, the buoyancy elements are attached to the water surface facing front side of the curtain or the guide element.

It is further preferred that the device according to the invention comprises a squeezing device, which is attached to the curtain or the guide segment and is adapted to the sinking of the device in the direction of the seabed support. In particular, by an interaction of the buoyancy elements with the Sinkeinrichtung the curtain or the guide segment can be stretched in the vertical direction between the seabed and the sea surface.

In a further preferred embodiment of the device according to the invention, the curtain has an outer segment and an inner segment, a plurality of damping elements being arranged between the outer segment and the inner segment. According to the invention, the damping elements are at least partially formed from gel and / or substantially spherical. Both a spherical geometry and the formation of a gel material have a positive effect on the sound damping properties of the curtain.

The object underlying the invention is further achieved by a curtain for use in a device for reducing the sound immission during pile driving at sea for foundations of offshore wind turbines, wherein the curtain according to a preferred embodiment described above, in particular according to claim 3, 4, 13 and / or 16 is formed.

The object underlying the invention is further achieved in a method of the type mentioned by the gas bubbles are performed by at least one device for guiding the gas bubbles. With regard to the advantages of the method according to the invention, reference is made to the advantages of the device according to the invention.

In a first preferred embodiment of the method according to the invention, the gas bubbles are guided by at least one curtain or guide segment. Preferably, the gas bubbles are guided in a space between two spaced curtains or guide segments.

In a second preferred embodiment of the method according to the invention, the gas bubbles are generated with at least one, preferably a plurality of substantially annular fluid nozzles and form an annular, preferably substantially cylindrical curtain of gas bubbles, wherein preferably a plurality of vertically stacked annular fluid nozzles a plurality of annular curtains from gas bubbles.

Fig. 1

einen Ausschnitt eines Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung zur Reduktion der Schallemissionen bei Rammarbeit auf See zur Gründung von Fundamenten von Offshore-Windkraftanlagen;

Fig. 2

einen Abschnitt einer erfindungsgemäßen im Wesentlichen ringförmigen Fluid-Düse mit mehreren Austrittsöffnungen zur Abgabe von Gas oder gasenthaltender Flüssigkeit;

Fig. 3

ein weiteres Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung zur Reduzierung der Schallimmissionen bei Rammarbeit auf See zur Gründung von Fundamenten von Offshore-Windkraftanlagen;

Fig. 4

ein weiteres Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung zur Reduzierung der Schallimmissionen bei Rammarbeit auf See zur Gründung von Fundamenten von Offshore-Windkraftanlagen; und

Fig. 5

einen Ausschnitt eines Ausführungsbeispiels eines erfindungsgemäßen Vorhangs.

The invention is described below with reference to preferred embodiments with reference to the figures. Show it:

Fig. 1

a detail of an embodiment of a device according to the invention for the reduction of noise emissions during pile driving at sea to found foundations of offshore wind turbines;

Fig. 2

a portion of a substantially annular fluid nozzle according to the invention having a plurality of outlet openings for dispensing gas or gas-containing liquid;

Fig. 3

a further embodiment of a device according to the invention for reducing noise emissions during pile driving at sea for the foundations of offshore wind turbines;

Fig. 4

a further embodiment of a device according to the invention for reducing noise emissions during pile driving at sea for the foundations of offshore wind turbines; and

Fig. 5

a section of an embodiment of a curtain according to the invention.

Fig. 1 shows a section of an embodiment of a device 1 according to the invention for the reduction of noise emissions during pile driving at sea to found foundations of offshore wind turbines. Three annular fluid nozzles 2 are arranged concentrically one above the other and vertically spaced from each other. The device 1 further comprises a retaining frame 8, which is arranged between the fluid nozzles 2 and which supports the fluid nozzles 2 against one another. The holding frame 8 comprises a plurality of struts 8a, 8b. Each two struts 8a, 8b are pivotally connected to each other or foldable by means of a joint 8c. The sides of the struts 8a, 8b opposite the joint 8c are pivotally or rotatably attached to an annular fluid nozzle 2, respectively. The joints 8 c are arranged centrally between two fluid nozzles 2. By such joints 8c, the device 1 can be folded, so that the transport and installation is simplified on site. On the holding frame 8 and / or the fluid nozzles 2, a device which can be used under water for guiding the gas bubbles generated by the fluid nozzles can be fastened (means for guiding the gas bubbles not shown).

According to Fig. 2 The illustrated annular fluid nozzle 2 according to the invention comprises a plurality of outlet openings 14 for dispensing gas or gas-containing liquid. The outlet openings 14 are arranged in two spaced-apart rows. The outlet openings 14 of a row are equidistant from each other. Furthermore, the fluid nozzle 2 comprises a feed channel 12 which communicates with the outlet openings 14, so that liquid containing gas and / or gas can pass from the feed channel 12 to the outlet openings 14.

In the Fig. 3 indicated curtains 6 are made of such a material and are dimensioned such that in the water rising or moving gas bubbles can not substantially pass through the curtains 6, while substantially transversely to the surface of the curtains 6 flowing water can at least partially pass through the curtains 6 , Each curtain 6 has a fabric structure having this selective permeability. Such properties can be implemented by curtains 6, which are made of textile material. The curtains 6 comprise a unilaterally needled nonwoven fabric. The nonwoven fabric comprises PET material, but other synthetic or natural fibers are also envisioned that exhibit similar permeability characteristics. The fabric structure has at least one of the following components: metallic fibers, plastic fibers, fabric fibers, neoprene, plastic film or fibers of mineral substances. Likewise, mixed fibers of different fiber components are conceivable. Even a woven combination of different fiber types has advantageous properties. The device 1 also has a holding frame 8. The holding frame 8 comprises a plurality of struts 8a, 8b, which are each connected to each other by means of a joint 8c pivotable to each other or foldable. The fluid nozzles 2 are arranged relative to the two curtains 6 such that the gas bubbles can be introduced into a gap 10 or more spaces between the two spaced curtains 6. After the gas bubbles have been introduced into the gap 10 or the interspaces 10, they are guided by the at least partially non-permeability for gases of the curtains 6 of these, wherein the orientation of the curtains 6 can influence and limit the flow direction of the gas bubbles. The holding frame 8 is designed such that the curtains 6 extend substantially in the vertical direction and the curtains 6 take on a substantially cylindrical shape. Furthermore, a plurality of fluid nozzles are arranged on the holding frame 8, preferably vertically spaced from each other. The two cylindrical curtains 6 are held particularly advantageously concentric with each other by the holding frame 8. The gap 10 and / or the interstices 10 thereby substantially a ring shape. In addition to the holding function, the holding frame 8 also assumes the optionally at least partial tensioning function of the curtains 6. The fluid nozzles 2 are arranged relative to the curtains 6 arranged concentrically relative to one another in such a way that the gas bubbles are produced in the intermediate space 10 between the two curtains, especially in this ascend. The fluid nozzles 2 in this case have a feed channel and a plurality of outlet openings which communicate with the feed channel. The feed channel is substantially annular. The fluid nozzles 2 are tube-shaped and the outlet openings are arranged along a row on the tube. The devices 1 has 3 fluid nozzles, which are annular and vertically spaced from each other. The number of fluid nozzles is not limited to three. In particular, the number of fluid nozzles depends on the overall dimensions of the device and on the field of application or purpose. It is advantageous if the fluid nozzles are designed as part of the holding framework, so that they can simultaneously take over holding and / or clamping function for the curtains or guide segments. The shape of the fluid nozzles 2 adapts advantageously to the design of the curtains 6 and preferably also to the shape of the holding frame 8. As shown in the figures, cylindrical or annular configurations are conceivable, but also rectangular or polygonal structures are conceivable.

According to Fig. 4 The device 1 comprises a curtain 6, which is fastened to a holding frame 8. The curtain 6 and the holding frame 8 are formed substantially cylindrical and enclose an area in which pile driving for foundations of offshore wind turbines are performed. The curtain 6 comprises a plurality of web segments 24, 26. The individual web segments 24, 26 extend between the sea surface 16 and the seabed 18. The web segments 24 have a greater width than the web segments 26. In particular, the comparatively thinner web segments 26 serve as connecting segments of the comparatively wider web segments 24. The connection between the web segments 24 and 26 has substantially no gaps. Thus, the sound generated when driving in the pile driving can be effectively damped. From the in Fig. 4 shown ramming piles 30a, 30b, 30c, 30d, 30e, 30f are the ramming piles 30a, 30b, 30c, 30d already fully rammed into the seabed, wherein the pile pile 30e was rammed approximately half in the seabed 18 and the pile work in the Pile pile 30f still outstanding.

On the sea surface 16 facing the front side of the curtain 6 buoyancy elements 20 are arranged, which are interconnected by means of coupling members 22. The buoyancy elements 20 are connected to each other by means of the coupling members 22 and attached to the curtain 6 and / or the holding frame 8, that they form a substantially circular ring. At the bottom of the sea 18 facing the front side of the curtain 6, a Sinkeinrichtung 28 is attached, which has supported by means of weights Sinkvorhang the device 1 in the direction of the seabed 18 and contributes to the maintenance of the desired position of the device 1.

By the interaction of the sinking device 28 and the buoyancy elements 20, a tightening or tensioning of the curtain 6 is achieved, so that accessibility of the area required for the pile work can be ensured.

According to Fig. 5 the curtain 6 has an outer segment 6a and an inner segment 6b. Between the outer segment 6a and the inner segment 6b formed of gel damping elements 32 are arranged, which are interconnected via connecting members 34. The damping elements 32 are further formed as balls. Due to the plurality of spherical damping element 32 between the outer segment 6a and the inner segment 6b of the curtain 6, the damping properties of the curtain are further increased.

LIST OF REFERENCE NUMBERS

1

Device for reducing noise emissions

2

Fluid nozzle

4

Device for guiding gas bubbles

6

curtain

6a, 6b

Inner and outer segment of the curtain

8th

Holding scaffold

8a, 8b

Striving the holding scaffold

8c

Joint of the holding scaffold

10

gap

12

feed

14

outlet openings

16

sea

18

Seabed

20

buoyancy element

22

coupling member

24

Railway segment of the curtain

26

Railway segment of the curtain

28

Sinkeinrichtung

30a-30f

piles

32

damping element

34

link

Claims (17)

1. A device (1) for reducing sound immissions during piling work at sea for the establishment of foundations of offshore wind power plants, having
   one or a plurality of fluid nozzles (2) to emit gas or gas-containing fluid to produce gas bubbles, and
   a device (4), usable under water, to guide the gas bubbles produced by the fluid nozzles (2), wherein the device for guiding the gas bubbles (4) has at least one curtain (6) which has an outer segment (6a) and an inner segment (6b),
   characterised in that between the outer segment (6a) and the inner segment (6b) there are arranged a plurality of deadening elements (32) formed at least partially of gel.
2. A device (1) according to claim 1,
   characterised in that the curtain (6) is composed of such a material and/or is dimensioned in such a manner that gas bubbles rising or moving in the water are substantially checked by the curtain (6), whereas water flowing substantially transversely to the surface of the curtain (6) can at least partially pass through the curtain (6).
3. A device (1) according to claim 1 or 2, characterised in that the curtain (6) has a fabric structure and/or comprises at least one of the following components: metallic fibres, plastics fibres, textile fibres, mineral materials, neoprene fabric, plastics sheet.
4. A device (1) according to any one of claims 1 to 3,
   characterised by at least one holding frame (8) to which the curtain (6) can be secured.
5. A device (1) according to claim 4, characterised in that the holding frame (8) is constructed in such a manner that the curtain (6) extends substantially in a vertical direction and/or the curtain (6) has a substantially cylindrical form and/or a plurality of fluid nozzles (2) are arranged on the holding frame (8), preferably in a vertically spaced apart manner.
6. A device (1) according to any one of the preceding claims, characterised in that the device for guiding the gas bubbles (4) has two curtains (6) which are spaced apart, in particular are arranged substantially concentrically to one another in the assembled state, wherein the fluid nozzles (2) are arranged in such a manner relative hereto that the gas bubbles can be introduced into the space (10) between the two spaced apart curtains (6).
7. A device (1) according to claim 6, characterised in that the fluid nozzles (2) are arranged in such a manner relative to the concentrically arranged curtains (6) that the gas bubbles are produced in the space (10) between the two spaced apart curtains (6), in particular rise therein.
8. A device (1) according to any one of the preceding claims, characterised in that the fluid nozzles (2) have a feed channel (12) and a plurality of outlets (14) communicating with this feed channel (12) and/or are tubular, and the outlets (14) are arranged in a row at the pipe.
9. A device (1) according to at least one of the preceding claims, characterised in that a plurality of fluid nozzles (2) are arranged spaced apart, in particular vertically spaced apart.
10. A device (1) according to at least one of the preceding claims, characterised in that a plurality of annular fluid nozzles (2) are arranged one above the other and two spaced apart, cylindrical curtains (6) are held by these nozzles.
11. A device (1) according to any one of the preceding claims, characterised in that the curtain (6) comprises a plurality of sheeting segments (24, 26), wherein the plurality of sheeting segments (24, 26) form a closed curtain in their entirety.
12. A device (1) according to any one of the preceding claims, characterised by one or a plurality of lift elements (20) secured to the curtain (6), wherein a plurality of lift elements (20) can be coupled by coupling members (22).
13. A device (1) according to any one of the preceding claims, characterised by a sinking device (28) which is secured to the curtain (6) and is designed to promote the sinking of the device in the direction of the sea floor.
14. A device (1) according to any one of the preceding claims, characterised in that the deadening elements (32) are substantially spherical.
15. A method of reducing sound immissions during piling work at sea for the establishment of foundations of offshore wind power plants, in which method gas bubbles are emitted into the sea water from at least one, preferably a plurality of fluid nozzles (2), wherein the gas bubbles are guided by at least one device for guiding the gas bubbles (4), the device for guiding the gas bubbles (4) has at least one curtain (6) which has an outer segment (6a) and an inner segment (6b), characterised in that between the outer segment (6a) and the inner segment (6b) there are arranged a plurality of deadening elements (32) formed at least partially of gel.
16. A method according to claim 15, characterised in that the gas bubbles are guided in a space (10) between two spaced apart curtains (6).
17. A method according to claim 15 or 16, characterised in that the gas bubbles are produced with at least one, preferably a plurality of substantially annular fluid nozzles (2) and form an annular, preferably substantially cylindrical, curtain of gas bubbles, wherein preferably a plurality of annular fluid nozzles arranged vertically one above the other form a plurality of annular curtains of gas bubbles.

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