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Title:
OFFSHORE WINDOW ASSEMBLY
Document Type and Number:
WIPO Patent Application WO/2017/202433
Kind Code:
A1
Abstract:
The present invention relates to a window assembly (1) for being mounted in an aperture/opening (5) in an offshore construction, the window assembly (1) comprising a window frame (2) adapted to be attached to an outer part (6) of said offshore construction, a window box (4) adapted to be attached to an inner part (8) of said offshore construction, and a membrane unit (3), where the membrane unit (3) is adapted to connect the window frame (2) with the window box (4), where the window frame (2) and the window box (4) each comprises an attachment means for releasably receiving the membrane unit (3). The present invention further relates to a method of mounting a window assembly (1) in an aperture/opening (5) in an offshore construction.

Inventors:
BUCH, Henning (Rantzausmindevej 197, 5700 Svendborg, 5700, DK)
CHRISTENSEN, Bjarne Bondegaard (Vængevej 20, 5700 Svendborg, 5700, DK)
Application Number:
DK2017/050170
Publication Date:
November 30, 2017
Filing Date:
May 23, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
C.C. JENSEN A/S (Løvholmen 13, 5700 Svendborg, 5700, DK)
International Classes:
B63B19/02
Foreign References:
FI854964A1987-06-14
JPS4412358Y11969-05-23
CN105443019A2016-03-30
GB388360A1933-02-23
GB934858A1963-08-21
Other References:
None
Attorney, Agent or Firm:
CHAS. HUDE A/S (H.C. Andersens Boulevard 33, 1780 Copenhagen V, 1780, DK)
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Claims:
Claims

1 . A window assembly (1 ) for being mounted in an aperture/opening (5) in an offshore construction, the window assembly (1 ) comprising

- a window frame (2) adapted to be attached to an outer part (6) of said offshore construction,

- a window box (4) adapted to be attached to an inner part (8) of said offshore construction, and

- a membrane unit (3), where the membrane unit (3) is adapted to connect the window frame (2) with the window box (4),

characterised in that,

- said window frame (2), window box (4) and membrane unit (3) are three separate elements. 2. A window assembly (1 ) according to claim 1 , wherein the window frame (2) and the window box (4) each comprises an attachment means (21 ,22) for releasably receiving the membrane unit (3).

3. A window assembly (1 ) according to claims 1 -2, wherein the window box (4) com- prises a plurality of side panels (4',4",4"',4""), each side panel (4',4",4"',4"") being adapted to connect to at least one other side panel (4',4",4"',4""), so that said side panels (4',4",4"',4"") together form the window box (4) when connected.

4. A window assembly (1 ) according to any of the preceding claims, wherein the membrane unit (3) comprises a plurality of membranes (3',3",3"',3"").

5. A window assembly (1 ) according to claim 4, wherein each membrane (3',3",3"',3"") is arranged adjacent to at least one other membrane (3',3",3"',3""), so that said membranes (3',3",3"',3"") together form a closed structure defining an inner volume of the window assembly when connecting the window frame (2) with the window box (4).

6. A window assembly (1 ) according to any of the preceding claims, wherein the attachment means (21 ,22) is adapted to adjust a distance between the window box (4) and the window frame (2).

7. A window assembly (1 ) according to any of the preceding claims, wherein the attachment means (21 ,22) comprises a first (27,29) and a second arm (28,30) adapted to receive/engage a membrane (3',3",3"',3"").

A window assembly (1 ) according to any of the preceding claims, wherein said window assembly (1 ) is adapted to dampen the level of sound passing through the window assembly (1 ), and/or comprises a fire-resistant material, and/or provides a gas-tight seal between said outer part (6) and said inner part (8) of the offshore construction.

A window assembly (1 ) according to any of the preceding claims, wherein said membrane unit (3) is adapted to dampen the level of sound passing through the inner volume of the window assembly (1 ).

A method of mounting a window assembly (1 ) in an aperture/opening (5) in an offshore construction, the method comprising the steps of

- providing a window frame (2), a window box (4), and a membrane unit (3),

- mounting the window frame (2) in said aperture/opening (5),

- attaching the window frame (2) to an outer part (6) of said offshore construction,

- connecting the membrane unit (3) to the window frame (2) by use of attachment means of the window frame (2) releasably receiving the membrane unit (3),

- connecting said window box (4) to the membrane unit (3) by use of attachment means of the window box (4) releasably receiving the membrane unit (3), and

- attaching the window box (4) to an inner part (8) of said offshore construction.

Description:
Offshore Window Assembly

The present invention relates to a window assembly for being mounted in an aperture/opening in an offshore construction, the window assembly comprising

- a window frame adapted to be attached to an outer part of said offshore construction,

- a window box adapted to be attached to an inner part of said offshore construction, and

- a membrane unit, where the membrane unit is adapted to connect the window frame with the window box.

The present invention further relates to a method of mounting a window assembly in an aperture/opening in an offshore construction. Window assemblies such as windows and portholes built into the structure of offshore constructions are commonly made up by a window frame and a window box. The window frame accommodates the glass and gasket system and is mounted directly in pre-defined carvings/cut-outs, i.e. apertures/openings, in the outer hull structure during the early construction process. So far, within the technical field of window assemblies, the window box is the inner part that makes up the air-, gas- and sound-tight connection/membrane between the inner bulkhead liner, i.e. the inner part of the hull structure, and the window frame. The window frame may be made of aluminum or steel.

During the construction and building of large vessels, platforms and other offshore con- structions, the window frames are typically installed at an early stage of the construction process. Only much later in the construction process, the inner (bulkhead) lining/panel, such as in accommodation and operation spaces, is established, so that the window box can be mounted. Window assemblies are commonly manufactured from fiber glass or from thin steel plate into a 3-dimensional pre-fabricated structure with a Width x Height x Depth (W x H x D) of up to 2000 x 3000 x 500 mm or even larger.

Window boxes made of fibreglass gives a smooth surface which does not need any fur- ther surface treatment. These window boxes are easy to mount and facilitates an adaption/adjustment of the depth dimension of the window assembly. However, window boxes made of fibreglass have the disadvantage that each window box shape requires its own mould which cannot be prepared until final specification, such as the wall thickness etc., has been defined. Furthermore, if the specifications are altered, the mould must be modified or rebuild which requires resources.

Window boxes made of steel have the disadvantage of requiring special welding processes during manufacturing and mounting so as not to risk that the steel plates making up the window boxes wriggle. Furthermore, the finishing and surface treatment are comprehensive.

Common to both types of window boxes described above is that they present disadvantages in terms of storage and shipping as they primarily require being produced and/or assembled prior to being shipped to the respective offshore construction site. Thus, such window boxes often result in a relatively large shipping volume, i.e. the space taken up by the product during shipping, and therefore result in relatively large shipping expenses. Furthermore, due to the size and shape of the assembled window boxes, the handling aboard the offshore construction is difficult. The window boxes should fit relatively perfectly into the carving/cut-out so that by applying already assembled window boxes there is a risk of re-production and/or re-mounting.

Within the present invention, the term offshore constructions is to be understood as seagoing vessels of all kinds (ships) and jack-up, fixed, floating and semi-submerged oil rigs (oil platforms / offshore platforms) and other floating or installations fixed on the sea bed for oil and gas production and storage a well as accommodation installations, such as hotels or sleeping quarters.

Thus, known window assemblies require a large shipping volume and are difficult and expensive to adjust to various dimensions. In accordance with the invention, there is provided a window assembly for being mounted in an aperture/opening in an offshore construction, the window assembly comprising

- a window frame adapted to be attached to an outer part of said offshore construction,

- a window box adapted to be attached to an inner part of said offshore construc- tion, and - a membrane unit, where the membrane unit is adapted to connect the window frame with the window box,

where said window frame, window box and membrane unit are three separate elements.

The aperture/opening in the offshore construction may be in the hull structure of the offshore construction and may as such be a carving/cut-out. Furthermore, the inner part of said offshore construction may be an inner lining of said offshore construction or hull structure.

It may be a wish for the constructor of an offshore construction to mount window assemblies with various widths, heights and/or depths. Thus, there is a need for a window assembly, the dimensions of which may easily be adjusted/customised to various requirements and not just to predetermined requirements.

Providing a window assembly, which is divided into a window frame, a window box and a membrane unit, facilitates that the window assembly can be manufactured and installed whenever it fits into the yard construction process and planning. This gives flexibility in both the manufacturing and the installation process. Furthermore, the logistics at the construction site is optimised as the parts of the window assembly may be shipped in steps so that minimal, available storing space is required.

In an embodiment, the window frame and the window box can each comprise an attachment means for releasably receiving the membrane unit.

This is an advantage in case the dimensions of the window assembly have to be adjusted, e.g. if the depth has to be adjusted as a new inner lining is installed, or if a different window assembly has to be installed in which case the existing window assembly has to be demounted which is facilitated by a releasable attachment so that the parts of the window assembly may be easily demounted and possibly be used again at another location. The attachment means may be a rabbet, flange, groove, tape-like means with the function of reattaching several times (such as Velcro), or a means with magnetic properties. Thus, the present invention provides a solution which is easy to manufacture, mount and demount and which provides an optimisation of the logistics. In an embodiment, the window box can comprise a plurality of side panels, each side panel being adapted to connect to at least one other side panel, so that said side panels together form the window box when connected.

The window box may comprise a plurality of side panels which together form the window box. Thus, each side panel may form a side/edge of the window box, so that e.g. a four- sided window box is formed by four side panels, where each side panel is connected to two other side panels, and a three-sided window box is formed by three side panels etc.

The side panels may be produced by forming long side panels from which side panels of the required length are cut out. Thus, any dimension of aperture/opening may be used in the offshore construction as the window box is easy to customise to the required dimensions. Also, the side panels are easy to prepare and produce, and the production of the side panels may be postponed until they are needed in the construction process.

No expensive moulds with fixed dimensions are needed for producing the window box in one piece. Furthermore, the window box may be packed and shipped/transported with a higher packing density (i.e. lower shipping volume) if it is produced as individual side panels and only assembled when the side panels have arrived at the offshore construction and the window box has to be installed. This results in reduced shipping costs and in reduced storage volume compared to if the window boxes are assembled before packing and shipping or are produced/moulded in one piece.

In an embodiment, the membrane unit can comprise a plurality of membranes.

The membrane unit may comprise a plurality of membranes which together form the membrane unit. Thus, each membrane may form a side/edge of the membrane unit, so that e.g. a four-sided membrane unit is formed by four membranes, and a three-sided membrane unit is formed by three membranes, etc.

The membranes may be produced by e.g. cutting out individual membranes from one or more larger membranes. Thus, any dimension of carvings/cut-outs may be used in the offshore construction as the membrane unit is easy to customise to the required dimensions. Thus, the membranes are easy to prepare and produce, and the production of the membrane unit may be postponed until it is needed in the construction process. No expensive moulds with fixed dimensions are needed for producing the membrane unit.

The membrane unit may be packed and shipped/transported with a low shipping volume if it is produced as a plurality of membranes and only assembled when the membranes have arrived at the offshore construction, and the membrane unit and window box have to be installed. This results in reduced shipping costs and in a reduced storage volume compared to if the membrane unit is assembled before shipping or is produced/moulded in one piece. In an embodiment, each membrane can be arranged adjacent to at least one other membrane, so that said membranes together can form a closed structure defining an inner volume of the window assembly when connecting the window frame with the window box. As stated above, each membrane may form a side/edge of the membrane unit, so that e.g. a four-sided membrane unit is formed by four membranes, and similarly for a three- sided membrane unit, or a many-sided membrane unit etc. Thus, each membrane may be arranged adjacent to at least one other membrane, e.g. where edges of two membranes are arranged adjacent to or touching each other, or where an edge of one mem- brane is arranged adjacent to or touching a surface of another membrane, or where a surface of one membrane is arranged adjacent to or touching a surface of another membrane.

Membranes of various shapes and sizes may be combined and form the membrane unit. The cross-sectional shape of the membrane unit may therefore be equal to the shape of the window frame and/or of the window box e.g. over the entire length of the membrane unit or at the ends of the membrane unit, said ends being attached to the window frame and the window box, respectively. In an embodiment, the attachment means can be adapted to adjust a distance between the window box and the window frame. The attachment means may be adapted to adjust the distance between the window box and the window frame so that the depth of the window assembly may easily be adjusted if required. An adjustment may be relevant as the distance between the outer part and the inner part of the hull structure can only be established with a certain tolerance. Also, an adjustment may be relevant if a new inner part is installed and the depth of the window assembly is altered thereby.

The adjustment may vary depending on the type of the attachment means. Thus, if the attachment means has the form of e.g. a groove receiving and holding the membrane unit, said distance may be adjusted, while the membrane unit is attached to the attachment means. On the other hand, if the attachment means is e.g. a tape-like means, the membrane unit may have to be detached before said distance can be adjusted. In an embodiment, the attachment means can comprise a first and a second arm adapted to receive/engage a membrane.

In an embodiment, at least part of the extension of said first and second arms can be adapted to fit the membrane closely.

The attachment means may comprise a first and a second arm adapted to receive/engage/hold the membrane unit or a membrane so that the membrane unit or membrane may be fixed (at least temporarily) relative to the attachment means. Either one or both of the ends of said arms may be in contact with said membrane/membrane unit during attachment. Either one or both of the sides of said arms may be in contact with said membrane/membrane unit during attachment.

At least part of the extension of said arms may be adapted to fit the membrane/membrane unit closely which provides stability during the attachment thus preventing the membrane/membrane unit from wriggling/moving relative to the attachment means.

In an embodiment, said window assembly can be adapted to dampen the level of sound passing through the window assembly, and/or can comprise a fire-resistant material, and/or can provide a gas-tight seal between said outer part and said inner part of the offshore construction. Thus, the window assembly may be customised to comprise one or more functions, such as effectively dampening the level of sound, being fire-resistant, and/or being gas-tight. Whether applying one or more of the functions may depend on inter alia the locations of the window assembly on the offshore construction, the type of offshore construction, aesthetic requirements, and various climate/environmental requirements for the offshore construction with respect to e.g. sound, fire and gas content.

The level of sound may be dampened by e.g. installing a window in the window box, such as installing a removable window, or by applying a membrane material which facil- itates dampening of the level of sound.

In an embodiment, said membrane unit can be adapted to dampen the level of sound passing through the inner volume of the window assembly. Thus, the membrane unit may comprise a material and/or a shape and/or a structure which facilitates dampening of the level of sound passing through the inner volume of the window assembly. The membrane unit may comprise a plurality of holes, such as through-going or blind holes adapted to absorb part of the sound pressure within said inner volume. The membrane unit may comprise an elastic and/or flexible material which is adapted to give in and reduce a sound pressure within said inner volume by moving/vibrating relative to the sound pressure.

Providing a membrane unit comprising a plurality of membranes further has the advantage that the membrane unit may be prevented from reverberating, at least partly, compared to if the membrane unit was manufactured as one unit, i.e. did not comprise individual membranes.

Providing a membrane unit comprising a plurality of membranes gives a window assembly which is easy to combine/configure with other (state of the art) standard solutions. Furthermore, addition of further effects/properties or characteristics to the membrane unit, such as sound absorbing features, a special color system marking for example an emergency exit, etc, is facilitated.

In an embodiment, the window box can comprise aluminium. Aluminium provides a good and aesthetical surface finish, and a possible anodising of the aluminium provides a robust surface.

Aluminium has a low weight compared to e.g. steel which means that a reduced weight has to be shipped to the offshore construction resulting in reduced shipping expenses. Furthermore, reduced weight means an easier handling of the window assembly.

In accordance with the invention, there is further provided a method of mounting a window assembly in an aperture/opening in an offshore construction, the method comprising the steps of

- providing a window frame, a window box, and a membrane unit,

- mounting the window frame in said aperture/opening,

- attaching the window frame to an outer part of said offshore construction,

- connecting the membrane unit to the window frame by use of attachment means of the window frame releasably receiving the membrane unit,

- connecting said window box to the membrane unit by use of attachment means of the window box releasably receiving the membrane unit, and

attaching the window box to an inner part of said offshore construction. In an embodiment, connecting the membrane unit to the window frame can comprise connecting each of the membranes of the membrane unit to the window frame by use of attachment means of the window frame releasably receiving the membranes, so that said membranes together can form a closed structure defining an inner volume of the window assembly.

In an embodiment, the method can further comprise the step of connecting each side panel of the window box to at least one other side panel, so that said side panels together form said window box when connected. In an embodiment, the window box and/or the membrane unit can be collected on-site.

The window assembly may be collected/assembled on-site at the offshore construction. Thus, the window frame, the window box and the membrane unit may be shipped as separate units which have not been assembled. Therefore, the total shipping volume, the shipping expenses and the required storage facilities are reduced compared to if the window assembly is shipped after being assembled. This is further reduced by providing the window box and/or the membrane unit as separate side panels and membranes, respectively.

In an embodiment, the window assembly can comprise a blind, e.g. the window box may comprise a means for holding a blind and/or for connecting a blind to the window box. The blind may be a roller blind or a Venetian blind or other. Providing a window assembly, which comprises a blind, gives the user the possibility of visually shutting off the window assembly. The structure and function of the window assembly and the method of assembling and mounting it will be described in more detail below with references to exemplary embodiments shown in the drawings wherein,

Fig. 1 shows an exploded, perspective view of a window assembly.

Fig. 2 shows a window box seen from the front.

Fig. 3 shows a window frame seen from the front. Fig. 4 shows a side view of an assembled window assembly.

Fig. 5 shows a top view of an assembled window assembly mounted in an offshore construction. Fig. 6 shows a fragmentary sectional view of section A in Fig. 5 in an enlarged scale.

Fig. 7 shows a fragmentary sectional view of section B in Fig. 5 in an enlarged scale.

In the figures, the window assembly is shown having a four-sided shape. However, it should be understood that other shapes, such as three-sided, many-sided, circular, oval etc. are also anticipated within the scope of the present invention.

Fig. 1 shows an exploded, perspective view of a window assembly.

The window assembly 1 may comprise a window frame 2, a membrane unit 3 and a window box 4. The window frame 2 is shown as already being attached to/mounted in an aperture/opening 5, such as a carving/cut-out 5, in an outer part 6 of an offshore construction, such as in an outer part 6 of a hull structure of an offshore construction, i.e. an outer hull structure.

The window box 4 may be attached to/mounted in an aperture/opening 7 in an inner part 8, such as an inner lining, of said offshore construction, for example in an inner part 8 of the hull structure of said offshore construction, i.e. an inner hull structure. The window box 4 may comprise a plurality of side panels which is illustrated in Fig. 1 as being a first 4', second 4", third 4"' and fourth side panel 4"" together forming a rectangle. Thus, each side panel 4',4",4"',4"" is adapted to connect to at least one other side panel 4', 4", 4"', 4"", so that said side panels 4', 4", 4"', 4"" together form the window box 4 when connected to each other. In Fig. 1 , said side panels 4',4",4"',4"" are illustrated as being straight, but one or more side panels 4',4",4"',4"" may also be non-straight. Said side panels 4',4",4"',4"" may be connected to each other by means of e.g. an adhesive or a connecting means, such as bolts or screws, or an angle bracket. If an angle bracket is used, the angle bracket may be attached to said side panels 4',4",4"',4"" by e.g. stamping. The membrane unit 3 is adapted to connect the window frame 2 with the window box 4. Thus, the membrane unit 3 forms an interface between the window frame 2 and the window box 4 and therefore separates the space 9 between the inner 8 and the outer part 6 of the hull structure (or offshore construction) from the inner volume 10 of the membrane unit 3 and thus of the window assembly 1 .

The membrane unit 3 may comprise a plurality of membranes. In Fig. 1 , the membrane unit 3 is illustrated as comprising a first 3', second 3", third 3"' and fourth membrane 3"" together forming a rectangular shape. As for the window box 4, other shapes are anticipated. Said membranes 3', 3", 3"', 3"" are illustrated as being planer, but other shapes such as non-planar, curved, etc. are foreseen.

The membrane unit 3 may comprise a variety of various materials. Preferably, the membrane unit 3 may comprise a material which may facilitate dampening the level of sound passing through the membrane unit 3, and/or be fire-resistant, and/or provide a gas-tight seal between said outer part 6 and said inner part 8 of the hull structure. Preferably, said material prevents thermal bridges, i.e. results in less heat exchange across the membrane unit 3 between said space 9 and said inner volume 10. Thus, the membrane unit 3 may comprise aluminium, and/or a sandwich panel, such as a sandwich of aluminium plates/panels or an aluminium composite panel, such as e.g. Dibond®. Applying a sand- wich of aluminium panels gives a membrane unit 3 which dampens the level of sound and reduces the heat exchange across the membrane unit 3.

The window assembly 1 may comprise an aluminium material. As such, one or more of the window frame 2, the window box 4 and the membrane unit 3 may partly or completely comprise an aluminium material. Applying an aluminium material results in a reduced weight of the window assembly 1 compared to if e.g. steel is used. Furthermore, the shipping expenses are reduced and the window assembly 1 becomes easier to handle/mount. Applying aluminium has the advantage that there is no need for special welding processes as is the case with e.g. steel. Instead, the parts comprising aluminium may be joint by a joint filler. In case the window assembly 1 is mounted on an offshore platform, there may be a requirement that the window frame 2 must resist high temperatures of e.g. above 600°C to withstand a fire. In such case, it may be an advantage that at least the outer part of the window frame 2 can withstand such temperatures in which case inter alia steel may be used to form the window frame 2.

The side panels 4',4",4"',4"" of the window box 4 and/or the membranes 3', 3", 3"', 3"" of the membrane unit 3 may be produced as extended sections and may as such be produced by extrusion. Producing said side panels 4',4",4"',4"" in extended sections, i.e. longer parts than required facilitates that various dimensions of window boxes 4 may be manufactured. Similarly, producing said membranes 3', 3", 3"', 3"" in extended sections, i.e. in longer and/or wider parts than required facilitates that various dimensions of membrane units 3 may be manufactured. Thus, the manufacturing of said side panels 4',4",4"',4"" and/or of said membranes 3', 3", 3"', 3"" may be postponed until the final dimensioning is determined and may be carried out either at the production facility or on- site at the offshore construction.

A window box sealing 1 1 may be applied between the window box 4 and inner surface 12 of the inner part 8 of the hull structure so as to ensure a solid attachment between the window box 4 and said inner part 8 and to prevent toxic gases from bypassing the window assembly 1 and enter the inside of the offshore construction. Similarly, a window frame sealing (not shown) may be applied between the window frame 2 and an outer surface 13 of the outer part 6 of the hull structure to provide sufficient attachment and sealing.

A first 14 and second membrane sealing 15 may be applied between the membrane unit 3 and the window box 4, and between the membrane unit 3 and the window frame 2, respectively. Said first 14 and second membrane sealing 15 may facilitate a sufficient attachment between the membrane unit 3 and the window box 4, and between the membrane unit 3 and the window frame 2, respectively, but may also prevent toxic/harmful gases from bypassing the membrane unit 3 and moving from the space 9 between the inner 8 and the outer part 6 of hull structure to the inner volume 10 of the membrane unit 3.

A means for mounting/holding a blind may be provided at an inner surface 16 of the window box 4. The means may as such comprise rails for guiding the blind.

Fig. 2 shows an assembled window box 4 seen from the front. The window box 4 is shown as comprising a first 4', second 4", third 4"' and fourth side panel 4"" together forming a rectangle. The window box 4 may hold a window (not shown) in the space 17 defined by said side panels 4', 4", 4"', 4"". The window may comprise glass which may dampen the level of sound passing through the membrane unit 3 from the surroundings of the offshore construction and into the interior of the offshore construction. The window may comprise a coating which may be heat-resistant and thus prevent the interior of the offshore construction from reaching a temperature higher than required. Fig. 3 shows an assembled window frame 2 seen from the front. The window frame 2 may have a rectangular shape, and the window frame 2 may comprise a first 2', second 2", third 2"', and fourth 2"" frame part which together form the window frame 2. As is the case with the window box 4 and the membrane unit 3, the window frame 2 may be shipped as said separate frame parts 2', 2", 2"', 2"" and assembled at the offshore con- struction which reduces shipping expenses due to reduced shipping volume and improves logistics at the construction site. However, it is foreseen that the window frame 2 may be manufactured in one piece.

An outer window 18 may be mounted in the window frame 3. The outer window 18 may comprise a glass material. The outer window 18 may comprise a sandwich structure of e.g. glass, polyvinyl butyral (pvb), air, and glass, and may be fire-resistant and dampen the level of sound moving from the surroundings of the offshore construction towards the interior of the offshore construction.

Fig. 4 shows a side view of an assembled window assembly 1 . The window assembly 1 is shown comprising a window box 4 and a window frame 2. The window frame 2 accommodates an outer window 18, where the outer window 18 is held by/attached to the window frame 2 by use of an attachment means illustrated in Fig. 4 as a plurality of bolts 19 and nuts 20. A membrane unit 3 is illustrated as being attached to the window frame 2 by an attachment means 21 of the window frame 2 and being attached to the window box 4 by an attachment means 22 of the window box 4. Thus, the membrane unit 3 is illustrated as connecting the window frame 2 with the window box 4.

Fig. 5 shows a top view of an assembled window assembly 1 mounted in an offshore construction. The outer part 6 of said hull structure is illustrated as comprising an aper- ture/opening 5, such as a carving/cut-out 5. In Fig. 5, the aperture/opening 5 is illustrated as being defined by a beam structure 23 of said outer part 6. The inner part 8 of the hull structure (offshore construction) is illustrated as comprising an aperture/opening 7 adapted to receive the window box 4 of the window assembly 1 . The outer part 6 of the hull structure separates the surroundings 24 of the offshore construction from the space 9 between the inner 8 and the outer part 6 of the hull structure. The inner part 8 of the hull structure separates the interior 25 of the offshore construction from the space 9 between the inner 8 and the outer part 6 of the hull structure.

As is illustrated in Fig. 4, the window frame 2 and the window box 4 may each comprise an attachment means 21 ,22 for releasably receiving the membrane unit 3. The distance d1 between the window frame 2 and the window box 4 may be adjusted/adapted at a later time, if e.g. requirements for better sound reduction comes up, or if new elements, which give better sound reduction, are found, or if different features such as the installation of blinds are wanted.

The dampening of the sound can be carried out by the window 18 in the window frame 2, and/or a window installed in the window box 4, and/or by the membrane unit 3. The membrane unit 3 may comprise a plurality of holes, either through-going or blind for further dampening the level of sound passing through the window assembly 1 . Said holes may have a diameter of 0.1 mm, but may also have a diameter of <1 mm or <5 mm. A porous material such as Rockwool may be arranged in said space 9 and may thus be placed on an outer side 26 of the membrane unit 3 to further increase the dampening.

Fig. 6 shows a fragmentary sectional view of section A in Fig. 5 in an enlarged scale.

In Fig. 6, the attachment means 22 of the window box 4 is shown to releasably receive the membrane unit 3. Said attachment means 22 may comprise a first 27 and a second arm 28 for receiving/engaging the membrane unit 3, or membrane 3', 3", 3"', 3"" of the membrane unit 3. At least part of the extension of the arms 27,28 may be adapted to fit the membrane unit 3 closely. In Fig. 6, the arms 27,28 are illustrated to closely fit the membrane unit 3 over the distance d2. However, a further distance d3 may closely fit the membrane unit 3 if required which facilitates adjustment of the distance d1 between the window frame 2 and the window box 4. Fig. 7 shows a fragmentary sectional view of section B in Fig. 5 in an enlarged scale.

In Fig. 7, the attachment means 21 of the window frame 2 is shown to releasably receive the membrane unit 3. Said attachment means 21 may comprise a first 29 and a second arm 30 for receiving/engaging the membrane unit 3 or membrane 3', 3", 3"', 3"" of the membrane unit 3. At least part of the extension of the arms 29,30 is adapted to fit the membrane unit 3 closely. In Fig. 7, the arms 29,30 are illustrated to closely fit the membrane unit 3 over the distance d4. However, the distance d4 may be reduced which facilitates adjustment of the distance d1 between the window frame 2 and the window box 4.

Modifications and combinations of the above principles and designs are foreseen within the scope of the present invention.