Coating element for coating a waterbed

Abstract

A coating element (1) for coating a waterbed is disclosed, with a waterproof lower membrane (2), a waterproof upper membrane (3) superimposed on the waterproof lower membrane, a lower internal membrane (5) made of fabric coupled with an upper side of the waterproof lower membrane (2), an upper internal membrane (6) made of fabric coupled with a lower side of the waterproof upper membrane (3), a ballast chamber (7) defined between the lower internal membrane and the upper internal membrane to contain ballast material that is injectable in fluid state, and a watertight joining device (4) to join one side of the element to a side of an adjacent element to create a continuous waterproof coating.

Description

Coating element for coating a waterbedBackground of the invention

[0001] The invention relates to a coating element for coating a waterbed, a method for manufacturing a coating element, and a waterproof coating made with coating elements.

[0002] The invention serves to create a waterproof coating of a waterbed (in particular, a channel, a basin, a dam or other manmade water feature), in particular enabling the coating to be installed directly below water, both with still water and with running water (for example a channel or the reservoir of a dam), without needing to empty the waterbed itself.

[0003] Specifically, but not exclusively, the invention in question can be applied to waterproof a course of water, for example a channel for supplying drinking water, water for irrigation, for navigation, for land improvement, for industrial purposes, or for yet other purposes in order to prevent soil erosion and / or infiltrations. The invention in question can however also be applied to other types of waterbeds, like, for example, basins for collecting and / or containing water and in dams.State of the art

[0004] The invention refers, in particular, to a coating element as in the preamble to the first claim. This coating element is known from patent publication WO 2016 / 016367 Al, of the same applicant, which shows a coating tubular element with two membranes welded together to form a tubular chamber to be filled with cement material in fluid state that will give rise to ballast for anchoring to the ground.

[0005] In figures 1A, IB and 1C, WO 2016 / 016367 Al discloses a channel 100 with a bottom 101 and two bank sides 102 and a waterproof coating consisting of panels 103 each comprising a waterproof geotextile lower membrane 104 and a waterproof geotextile upper membrane 105 joined together along the peripheral edges forming a large bag that defines a tubular chamber; the individual panels 103 are factory-made, wound into a roll, stored, sent to the place of installation and installed by being unwound directly underwater, joining the adjacent panels 103 by waterproof zippers 106; each panel 103 is then anchored to the ground by pumping a fluid ballast 107 into the tubular chamber by a hose 108 with a pressure that is suitable for overcoming the pressure of the surrounding water, such that the panel 103 inflates to adopt a shape permitted by internal tension members 109 that connect the waterproof lower membrane 104 to the waterproof upper membrane 105.20250517 WO EN

[0006] The disclosed prior art is effective in waterproofing waterbeds, in particular channels and / or basins of water with moving water.

[0007] Some improvable aspects of the aforementioned prior-art system are the toughness of the coating and the long-term hermetic seal guarantee for any type of waterbed and for any type of use.

[0008] The known system disclosed above provides effective and durable waterproofing provided that the coating does not break during the filling steps.

[0009] Another drawback of the prior art is the risk of breakage of the connecting tension members between the waterproof upper membrane and the waterproof lower membrane (which tension members are obtained by elastic geomembrane bands welded on both sides), in particular during the filling steps, with subsequent loss of the desired mattress geometric conformation of the coating element. As the geomembrane is elastic, the system is subject to great deformation during the step of filling with the ballast material. The elements subject to breaking are, in particular, the welding and the elastic material with which the bands are created. The resistance to peeling of the welding of the banks makes the bans weaker than the membranes, so that the ballast material is injected slowly in order not to overload the welding.

[0010] In the case, for example, of a channel, the loss of the desired shape of the coating element causes a reduction in the section of the channel with a decrease in the flowrate and, in more serious cases, an obstruction of the section of the channel, with consequent regurgitation and overflow of the water from the channel, weakening of the banks until breakage is caused with resulting collapse of the entire channel.Summary of the invention

[0011] One object of the invention is succeeding in meeting one or more of the aforesaid needs of the prior art.

[0012] One object of the invention is creating a coating element suitable for coating a waterbed in an effective and durable manner.

[0013] One object of the invention is to provide an alternative solution to those of the prior art to create a waterproof coating of a waterbed, in particular a coating that can be placed and installed directly underwater, both with still and flowing water, without needing to empty the waterbed.

[0014] One object of the invention is to provide a coating element that is20250517 WO ENconstructionally tough and easy to install.

[0015] One advantage of the invention is to enable the quantity of mixture injected over time to be increased in order to fill the ballast chamber of the coating element rapidly, decreasing the risk of breakage of the element and ensuring that the desired form of mattress is obtained.

[0016] One advantage is shortening filling time and thus decreasing labour costs and the means used in the operation.

[0017] One advantage is to provide a coating element with great resistance and absolute waterproofing reliability, significantly reducing the risks of deformation of the element and of creating obstructions.

[0018] Such objects and advantages, and still others, are achieved by a coating element according to one or more of the claims set out below.

[0019] The coating element comprises a waterproof lower membrane (in particular, a waterproof geomembrane), a waterproof upper membrane (in particular, a waterproof geomembrane) superimposed on the waterproof lower membrane, a lower internal membrane (in particular, made of fabric) coupled with an upper side of the waterproof lower membrane, an upper internal membrane (in particular, made of fabric) coupled with a lower side of the waterproof upper membrane, and a ballast chamber defined between the lower internal membrane and the upper internal membrane to contain ballast material that is injectable in fluid state.

[0020] To sum up, it can be stated that the aforesaid coating element enables the mechanical resistance function to be at least partially separated, which mechanical resistance is mainly assigned to the lower and upper internal membranes by the waterproofing function that is mainly assigned to both the lower and upper membranes or to at least one of the lower and upper membranes.

[0021] The mechanical resistance function may be mainly assigned, in particular, to a single internal bag that may be formed by the lower and upper internal membranes that are mutually joined on the edges.

[0022] The waterproof lower membrane and / or the waterproof upper membrane may be made, in particular, of polyvinyl chloride PVC or of another polymer material.

[0023] The lower internal membrane (made of fabric) and the upper internal membrane (made of fabric) may form internally a bag or sack (made of fabric) configured20250517 WO ENto connect together the waterproof upper membrane (geomembrane) and the waterproof lower membrane (geomembrane) and to contain the injectable ballast material (cement grout). The internal bag, made of fabric, may be highly resistant.

[0024] The internal bag may be, for example, made of polypropylene fabric.

[0025] The two sides of the internal bag made of fabric (i.e. the lower internal membrane and the upper internal membrane) may be joined together by a plurality of joining tension members which are also made of fabric and joined to the fabric that forms the two sides of the internal bag so as to form a single piece of fabric.

[0026] The tension members, made of fabric, may be created (shaped, sized and connected to the internal bag, which is also made of fabric) so as to obtain very high joining efficacy and / or joining toughness of the two sides of the bag.

[0027] The upper side and the lower side of the internal bag (made of fabric) are connected to the respective geomembranes during production in the factory.

[0028] In particular, the propylene bag may be glued to the geomembranes in polyvinyl chloride PVC with a polyurethane adhesive (in particular, a highly resistant and high-quality polyurethane adhesive, for example an adhesive of the type used for applications in the car industry).

[0029] In this manner, the connection between the two layers (waterproof lower membrane and waterproof upper membrane) is obtained by the internal bag made of fabric, the resistance of which can also be very high and can be determined on the basis of design needs. Arranging the bag made of fabric inside the two layers means that the mechanical resistance function is performed by the internal bag, whereas the waterproofing function is ensured by at least one of the two outer layers, or by both (flexible geomembranes).

[0030] The waterproof upper layer (membrane) of the coating element may consist, for example, of a polyvinyl chloride PVC geomembrane that is 2 ± 0.5 mm thick. The waterproof lower layer (membrane) of the coating element may consist, for example, of a PVC geomembrane that is 2.5 ± 0.5 mm thick. The thickness of the lower waterproof layer may be, in particular, greater than the thickness of the upper waterproof layer.

[0031] It is possible to provide a basic layer (coupled with the lower waterproof layer) of the coating element, having the function of an anti-piercing layer. The base layer may be made of a nonwoven geofabric (for example of polypropylene). The base layer may have, in particular, a grammage of about 500 g / m2. The base layer (anti-punching layer) may be20250517 WO ENcoupled by welding with the lower impermeable layer.

[0032] It is possible, in particular, for the lower layer to be mainly created to ensure the waterproof function, whereas the upper layer is mainly created to ensure the function of containing the injected ballast material at least until it sets.

[0033] As said, the geomembrane surfaces (made, for example, of PVC or of another polymer material) may be glued to the internal bag (made of fabric). It is possible to carry out a pre-treatment (for example, a corona treatment) on one or both the surfaces to be glued to improve the adhesive properties.

[0034] In experiments, it has been ascertained that the adhesion between the internal bag and the PVC geomembrane is significantly resistant, in particular in a peeling resistance test (on aged samples) and / or a tear-resistance test (on aged samples).

[0035] In particular, laboratory tests have shown that gluing between PVC and polypropylene PP by polyurethane PU-based glue is resistant to peeling and / or tearing after aging in conditions of exposure to ice and to contact with water.

[0036] It has been found that exposure to heat causes a not-excessive decrease in resistance to peeling, within the limit value of a 50% decrease. It has also been found that exposure to heat causes a not-excessive decrease in resistance to tearing, well within the acceptable limit value of 0.16 N / mm.

[0037] It has also been found that the contact of the PVC with the PU-based adhesive does not entail any phenomenon of deterioration in the properties of the geomembrane, in particular does not cause any particular loss of mass of the PVC through aging with respect to the loss of mass through aging without contact with adhesive. Further, the change in colour of the PVC after aging in contact with PU-based adhesive is identical to the change in colour of the PVC without contact with adhesive.

[0038] Moreover, contact with the alkaline environment (cement) was found to have little negative impact on the mechanical properties of the PU-based adhesive (tensile stress resistance decreased by 5% and elongation remains unvaried).

[0039] The structure of the mattress with internal bag was also tested, using samples of internal bag with different spacing and different thicknesses of the internal meshes, where the internal meshes are defined by the joining tension members of the two sides of the bag, in which the different samples of bag have been coupled with the PVC geomembranes. In particular, the resistance of the samples was evaluated by constructing a20250517 WO ENmattress measuring 2 m x 4 m and pumping water inside.

[0040] The structure of the mattress is particularly robust using tension members, for example in the form of flexible longitudinal tension elements (for example threads, ropes, cords or the like), made of fabric and distributed to form a grid with internal meshes spaced apart from one another (for example, by about 10 cm). Distributing the tension members enables a desired mattress conformation of the structure filled with the ballast material to be obtained. The internal connections (made for example with polypropylene fabric tension members) do not show breakages below the axial load generated by filling the structure with the ballast material.

[0041] The ballast material in fluid state (mortar) may be pumped with one or more injection pipes each of which has an inlet outside the mattress. The pipes may be removed after installation.Brief description of the drawings

[0042] The invention may be better understood and implemented with reference to the attached drawings that illustrate some embodiments thereof by way of non-limiting example, in which:Figures 1A, IB and 1C show a prior art solution disclosed by patent publication WO 2016 / 016367 Al, where Figure 1A is a cross section of a channel with a waterproof coating, Figure IB is a top view of a portion of the channel, and Figure 1C shows an injection step of injecting ballast material into an element of the waterproof coating;Figure 2 is a partial cross section of a first embodiment of a coating element made according to the invention, in an inflated configuration, i.e. when the coating element is filled with the ballast material, where, for greater simplicity and clarity, the ballast material is not illustrated;Figure 3 is an enlarged detail of Figure 2;Figures 4 to 9 show six steps of a method of building the coating element of Figure 2 in a factory;Figures 10 and 11 show two enlarged details of Figure 9;Figure 12 is a cross section, with several interruptions, of a second embodiment of a coating element made according to the invention, in a non-inflated configuration, i.e. when the coating element has not yet been filled with the ballast material and is suitable for being rolled up for transport and then unrolled during the step of laying20250517 WO ENand installing on a waterbed;Figures 12A and 12B are two enlarged details of Figure 12;Figures 13 A, 13B and 13C show three steps of a method of building in a factory the coating element of Figure 12 relating to the building of the left end (with reference to Figure 12) of the coating element;Figures 14A and 14B show two steps of a method of building in a factory the coating element of Figure 12 relating to the joining together of two adjacent single coating elements;Figures 15 A, 15B and 15C show three steps of a method of building in a factory the coating element of Figure 12 relating to the building of the right end (with reference to Figure 12) of the coating element;Figure 16 is a cross section, with several interruptions, of a coating element made according to the invention, in which the coating element is joined to an adjacent coating element to form a waterproof coating, in an inflated configuration, i.e. when the coating element is filled with the ballast material, where, for greater simplicity and clarity, the ballast material is not illustrated;Figures 16A, 16B and 16C are three enlarged details of Figure 16;Figure 17 is a partial section, according to a cross-section plane, of a third embodiment of a coating element made according to the invention, in an inflated configuration, in which the ballast material is visible that fills the mattress structure of the coating element;Figure 18 is a partial section of the coating element of Figure 17, according to a longitudinal section plane (orthogonal to the cross-section plane of Figure 17), in which, for greater clarity, the ballast material is not visible;Figure 19 is a partial plan view of the coating element of Figure 17 that shows, schematically, the arrangement of the tension members;Figure 20 is a partially sectioned perspective view of a part of a coating consisting of coating elements created according to a fourth embodiment of the invention, in an inflated configuration, with some parts removed to show off others better.Detailed description

[0043] With reference to Figures 2 to 20 mentioned above, identical elements of different embodiments have been indicated, for greater clarity and simplicity of exposition,20250517 WO ENby the same numbering.

[0044] A coating element for coating a waterbed has been indicated overall by 1.

[0045] The coating element 1 comprises a waterproof lower membrane 2 and a waterproof upper membrane 3 superimposed on the waterproof lower membrane 2. The terms “lower” and “upper” refer to the configuration in which the coating element 1 is laid and installed in the waterbed.

[0046] At least one of the aforesaid lower membrane 2 and upper membrane 3 is waterproof. In this embodiment, both the lower membrane 2 and upper membrane 3 are waterproof. The waterproof lower membrane 2 may comprise, in particular, a geomembrane. The waterproof upper membrane 3 may comprise, in particular, a geomembrane.

[0047] The coating element 1 comprises a watertight joining device 4 configured to join a lateral edge of the coating element 1 to a lateral edge of another coating element arranged adjacently so as to be able to create a continuous coating.

[0048] The coating element 1 comprises a lower internal membrane 5 with a side of membrane coupled with an upper side of the waterproof lower membrane 2.

[0049] The coating element 1 comprises an upper internal membrane 6 with a side of membrane coupled with a lower side of the waterproof upper membrane 3. The lower internal membrane 5 and the upper internal membrane 6 are arranged internally facing one another.

[0050] The lower internal membrane 5 may be, in particular, made of fabric. The upper internal membrane 6 may be, in particular, made of fabric.

[0051] The coating element 1 comprises a ballast chamber 7 that is defined in a space comprised between the lower internal membrane 5 and the upper internal membrane 6. The ballast chamber 7 is thus interposed between the waterproof lower membrane 2 and the waterproof upper membrane 3. The ballast chamber 7 is configured to contain ballast material that can be injected in fluid state inside the ballast chamber 7.

[0052] The lower internal membrane 5 and the upper internal membrane 6 may be, in particular, joined together along an edge zone to form a bag that can contain the ballast material.

[0053] The lower internal membrane 5 may be, in particular, coupled with permanent fixing to the waterproof lower membrane 2. The upper internal membrane 6 may be, in20250517 WO ENparticular, coupled with permanent fixing to the waterproof upper membrane 3.

[0054] The lower internal membrane 5 may be, in particular, glued to the waterproof lower membrane 2. The upper internal membrane 6 may be, in particular, glued to the waterproof upper membrane 3.

[0055] The lower internal membrane 5 may be, in particular, made of polypropylene. The waterproof lower membrane 2 may be, in particular, made of polyvinyl chloride. The lower internal membrane 5 may be, in particular, glued to the waterproof lower membrane2 by a polyurethane-based glue.

[0056] The upper internal membrane 6 may be, in particular, made of polypropylene. The waterproof upper membrane 3 may be, in particular, made of polyvinyl chloride. The upper internal membrane 6 may be, in particular, glued to the waterproof upper membrane3 by a polyurethane-based glue.

[0057] The coating element 1 may comprise, in particular, one or more internal flexible tension members 8 arranged between the lower internal membrane 5 and the upper internal membrane 6 to connect together the aforesaid lower internal membrane 5 and upper membrane 6. It is possible to provide, in particular, a plurality of tension members 8 so distributed as to form a grid.

[0058] Each tension member 8 may comprise, in particular, a flexible tension element (extending in length, for example in the form of a joining thread, rope, cord or the like) that is made of fabric and has two end edges that are joined integrally, respectively, to the lower internal membrane 5 and to the upper internal membrane 6. Each joining tension member may be made, in particular, of a “ripstop” reinforced fabric.

[0059] Each tension member 8 made of fabric may be joined, in particular, to the lower internal membrane 5 made of fabric and to the upper internal membrane 6 made of fabric so as to form a single body made of fabric.

[0060] The waterproof lower membrane 2 may be, in particular, divided into two or more portions of waterproof lower membrane 2a, 2b, ... which are welded together. The number of portions may be, in particular, two, three, four, five, or more than five.

[0061] The lower internal membrane 5 may be, in particular, divided into two or more portions of lower internal membrane 5a, 5b, .... Each portion of lower internal membrane 5a, 5b, ... has a side coupled with an upper side of a respective portion of waterproof lower membrane 2a, 2b, ....20250517 WO EN

[0062] The waterproof upper membrane 3 may be, in particular, divided into two or more portions of waterproof upper membrane 3a, 3b, ... which are welded together. The number of portions may be, in particular, two, three, four, five or more than five.

[0063] The upper internal membrane 6 may be, in particular, divided into two or more portions of upper internal membrane 6a, 6b, .... Each portion of upper internal membrane 6a, 6b, ... has a side coupled with a lower side of a respective portion of waterproof upper membrane 3a, 3b, ....

[0064] The coating element 1 may comprise, in particular, two lateral closing elements 9 arranged on two respective edge side zones of the coating element 1. Each of the aforesaid two lateral closing elements 9 may comprise, in particular, a lateral closing membrane 10. Each of the aforesaid two lateral closing elements 9 may comprise, in particular, an internal lateral closing membrane 11 coupled with the lateral closing membrane 10. The lateral closing membrane 10 is waterproof.

[0065] The internal lateral closing membrane 11 may comprise, in particular, a side of membrane coupled with an internal side of the lateral closing membrane 10. Each of the aforesaid two lateral closing elements 9 may be configured, in particular, so as to form a loop to close the coating element 1 laterally hermetically.

[0066] The lateral closing element 9 may create a hermetic lateral closure as a lower end of the lateral closing membrane 10 is sealing joined with the waterproof lower membrane 2 and an upper end of the lateral closing membrane 10 is sealing joined with the waterproof upper membrane 3.

[0067] The lateral closing membrane 10 may comprise, in particular, a geomembrane. The internal lateral closing membrane 11 may be, in particular, a membrane made of fabric.

[0068] The coating element 1 may comprise, in particular, two joining wings 12 arranged on two respective lateral zones of the coating element 1 that extend in a longitudinal direction and are opposite one another. The watertight joining device 4 may be arranged on the aforesaid joining wings 12. In particular, each joining wing 12 may be connected to at least one of the aforesaid lower and upper membranes 2 and 3 (in the specific embodiment, to the waterproof lower membrane 2). Each joining wing 12 may comprise, in particular, a geomembrane.

[0069] It is possible, in particular for each of the two opposite side zones, for the20250517 WO ENrespective joining wing 12 to have an end engaged between the lower end of the respective lateral closing membrane 10 and the waterproof lower membrane 2.

[0070] The coating element 1 may comprise, in particular, a protective layer 13 (or base layer having the function of anti-punching layer) coupled with a lower side of the waterproof lower membrane 2. The protective layer 13 may be made, in particular, of a geotextile. The protective layer 13 may be made, in particular, of a nonwoven geotextile, for example of polypropylene.

[0071] The watertight joining device 4 may comprise, in particular, a zipper. In particular, the coating element 1 has two lateral zones that extend in a longitudinal direction and are opposite one another, on each of which a respective toothed band 4a is arranged that is part of the zipper.

[0072] A method of manufacturing a coating element, in particular a coating element 1 as disclosed above is disclosed.

[0073] The method comprises the step of coupling a side of a first membrane made of fabric (indicated by 5 because it will form the lower internal membrane 5) with a side of a first geomembrane (indicated by 2 because it will form the waterproof lower membrane 2).

[0074] The method comprises the step of coupling a side of a second membrane made of fabric (indicated by 6 because it will form the upper internal membrane 6) with a side of a second geomembrane (indicated by 3 because it will form the waterproof upper membrane 3).

[0075] The method comprises the step of coupling two opposite lateral edges of the first geomembrane 2 with two opposite lateral edges of the second geomembrane 3 such that the first membrane made of fabric 5 and the second membrane made of fabric 6 are arranged facing one another to define the ballast chamber 7 suitable for receiving the injected ballast material in fluid state.

[0076] The method comprises the step of attaching, with a watertight joint, the two toothed bands 4a of the watertight zipper at the two lateral zones of the coating element 1.

[0077] The method may comprise, in particular, the step of forming the two lateral closing elements 9 respectively on the two lateral zones. Each lateral closing element 9 may be formed by coupling a side of an internal lateral closing membrane 11 (made of fabric) with an internal side of a lateral closing membrane 10 (made of geomembrane) and coupling two opposite ends of the lateral closing membrane 10 with the first geomembrane20250517 WO EN2 and respectively, with the second geomembrane 3, so that the element 9 forms a watertight lateral closing loop.

[0078] Also a waterproof coating for a waterbed is disclosed. The coating comprises a plurality of coating elements 1 made as disclosed previously, arranged side by side and joined together. The coating comprises, for each of the aforesaid coating elements 1, ballast inserted by injecting fluid cement material into the respective ballast chamber 7.

[0079] Figure 12 shows a coating element 1 in which the lateral closing element 9 shown on the right, which is built bigger than the one shown on the left, is folded on itself in order not to be superimposed on the toothed band 4a shown to the right and thus leaves the toothed band 4a uncovered and free in the step of laying the coating element to facilitate closing of the watertight joining device 4 (zipper), i.e. joining adjacent coating elements together to form a continuous coating. After this closure and before injecting the ballast material, the lateral closing element 9 shown on the right may be extended to cover the watertight joining device 4 and thus act as a protection for the device (see Figure 16C).

[0080] The material of the waterproof lower membrane 2 and / or the material of the waterproof upper membrane 3 may consist of a waterproof membrane made of PVC or another synthetic resin, for example a geomembrane with a thickness comprised between 1 and 5 mm, and a low permeability coefficient K (according to Darcy’s law), for example a coefficient K comprised in a range from IO-9m / s to ICT15m / s.

[0081] The waterproof lower membrane 2 may be coupled, in particular, with the protective layer 13, consisting of a geotextile layer suitable for contact with the ground, configured to ensure protection against perforation and provide an appropriate friction coefficient with the terrain.

[0082] The waterproof lower membrane 2 (for example a geomembrane that is 2.5 mm thick) may be, in particular, hot coupled during the production step with the protective layer 13 (for example a polyester geotextile with grammage of about 500 g / m2).

[0083] Figure 13 A shows, as part of the construction of the coating element, a welding step in which a lower edge of the lateral closing element 9 is welded to an end of the portion of waterproof lower membrane 2a situated on the left side of the coating element 1 (where “left” means with reference to the figures). Figure 13B shows a welding step in which an upper edge of the lateral closing element 9 is welded to an end of the portion of waterproof upper membrane 3a situated on the left side of the coating element 1. Figure20250517 WO EN13C shows a welding step in which a joining wing 12, bearing a toothed band 4a, is welded to the lower edge of the lateral closing element 9.

[0084] Figure 14A shows a welding step between two portions of waterproof lower membrane arranged adjacently (for example between the portions 2a and 2b, as in the figure, but also between the portions 2b and 2c, etc). Figure 14B shows a welding step between two portions of waterproof upper membrane arranged adjacently (for example between the portions 3a and 3b, or between the portions 3b and 3c, etc).

[0085] Figure 15A shows a welding step in which a joining wing 12, bearing a toothed band 4a, is welded to an upper side of an end edge of the portion of waterproof lower membrane situated on the right side of the coating element 1 (where this portion of waterproof lower membrane situated on the right side has been indicated in this specific embodiment by the numbering “2e” and where “right” means with reference to the figures). Figure 15B shows a welding step in which a lateral closing element 9 (the larger one arranged on the right side of the coating element 1) is welded to the joining wing 12. Figure 15C shows a welding step in which a lower side of an end edge of the portion of waterproof upper membrane 3e (situated on the right side of the coating element 1) is welded above the lateral closing element 9. In this case, the lateral closing element 9 on the right comprises both the lateral closing membrane 10, and the internal lateral closing membrane 11.

[0086] As said, one of the lateral closing elements 9 (in this embodiment the one on the right) is so constructed as to be superimposable (when extended) on the watertight joining device 4 after ballasting to protect the device, but also so as to be flexible (before ballasting) and thus foldable on itself (see Figure 12B) so as to uncover the toothed band 4a during the step of joining the coating elements by a zipper.

[0087] Figures 17-19 show in greater detail the arrangement of the tension members 8.

[0088] With 14, the layers of adhesive have been shown that are used to glue the waterproof lower membrane 2 to the lower internal membrane 5 and to glue the waterproof upper membrane 3 to the upper internal membrane 6. With 15, the ballast material has been indicated that fills the ballast chamber.

[0089] In this embodiment, the tension members 8 comprises threads made of fabric each of which has a lower end attached to the lower internal membrane 5 and an upper end attached to the upper internal membrane 6.20250517 WO EN

[0090] The tension members 8 are so configured that the ballast material 15 has filled the ballast chamber defined between the lower internal membrane 5 and the upper internal membrane 6, each tension member 8 is arranged tilted with respect to the lower internal membrane 5 and with respect to the upper internal membrane 6, i.e. arranged obliquely to a prevalent lying plane of the lower internal membrane 5 and with respect to a prevalent lying plane of the upper internal membrane 6.

[0091] It is possible, as in this specific embodiment, for the tension members 8 to be distributed and attached to the lower internal membrane 5 and upper membrane 6 so that the tension members 8 are oblique according to different tilts, in particular half of the tension members 8 have a first tilt and the other half have a second tilt that is different from the first.

[0092] In particular, the tension members 8 may be so arranged as to form, if seen in a plan view (Figure 19), a grid ordered with approximately at least one hexagonal arrangement (even if the hexagons might not be regular). In order to make this hexagonal arrangement clearer, in Figure 19 the fixing zones fixing the tension members 8 to the lower internal membrane 5 have been indicated by dashed lines 5’ and the fixing zones fixing the tension members 8 to the upper internal membrane 6 have been indicated by dashed lines 6’.

[0093] Each tension member 8 (which may consist, in particular, of threads) may be made of polypropylene and / or of polyamide. Each internal membrane (lower membrane 5 and upper membrane 6) may comprise, in particular, a fabric with a polyamide or polypropylene warp and with a polyethylene or polypropylene weft, in any possible combination of warp and weft materials. In this specific embodiment, both the lower internal membrane 5 and the upper internal membrane 6 are made of a fabric with a polyamide warp and with a polyethylene weft.

[0094] Figure 20 shows an embodiment in which the tension members 8 (in the form of threads) are so configured as to be perpendicular to the membranes (in particular, to the lower internal membrane 5 and to the upper internal membrane 6), rather than tilted as in the embodiment of Figures 17-19. Further, in this embodiment anchoring or gripping the tension members 8 to the lower internal membranes 5 and upper membranes 6 occurs through points, rather than lines as in the embodiment of Figures 17-19.

[0095] In the embodiment of Figure 20, the anchoring or gripping points of the tension20250517 WO ENmembers 8 are distributed to form a grid with square meshes. Each square mesh may measure, for example, about 15x15 centimetres.

[0096] It is possible, in other embodiments that are not illustrated, for the anchoring points of the tension members 8 to be distributed to form a grid with rectangular meshes. Each rectangular mesh may measure, for example, AxB centimetres, where the length A may be comprised, in particular, between 5 centimetres and 30 centimetres and the length B may be comprised, in particular, between 5 centimetres and 30 centimetres.20250517 WO EN

Claims

CLAIMS1. Coating element (1) for waterproofing a waterbed, said coating element (1) comprising: a lower membrane (2) and an upper membrane (3) superimposed on said lower membrane (2), where “lower” and “upper” refers to said coating element (1) installed in said waterbed, at least one of said lower and upper membranes being waterproof; a watertight joining device (4) configured to join one side of said coating element (1) with one side of an adjacent coating element to create a continuous coating; and a ballast chamber (7) which is interposed between said lower and upper membranes (2 and 3) and which is configured to contain ballast material which may be injected into said ballast chamber; characterized by comprising: a lower internal membrane (5) with a membrane side coupled with an upper side of said lower membrane (2); and an upper internal membrane (6) with a membrane side coupled with a lower side of said upper membrane (3); said lower and upper internal membranes (5 and 6) being arranged facing each other and said ballast chamber (7) being defined in a space between said lower and upper internal membranes (5 and 6).

2. Coating element according to claim 1, comprising tension members (8) arranged between said lower internal membrane (5) and said upper internal membrane (6) to mutually connect said internal membranes.

3. Coating element according to claim 2, wherein said lower and upper internal membranes (5 and 6) and said tension members (8) are made of fabric.

4. Coating element according to claim 2 or 3, in which each tension member (8) has two ends solidly joined, respectively, to said lower internal membrane (5) and to said upper internal membrane (6).

5. Coating element according to claim 4, wherein said two ends of the tension member are arranged in such a way that, when said ballast chamber (7) contains the ballast material, the tension member (8) is inclined with respect to said lower internal20250517 WO ENmembrane (5) and to said upper internal membrane (6).

6. Coating element according to claim 4, wherein said two ends of the tension member are arranged so that, when said ballast chamber (7) contains the ballast material, the tension member (8) is arranged perpendicular to said lower internal membrane (5) and to said upper internal membrane (6).

7. Coating element according to any one of claims 2 to 6, wherein each of said tension member (8) is in the form of a flexible tension member.

8. Coating element according to any one of the preceding claims, wherein said lower internal membrane (5) is made of fabric and / or wherein said upper internal membrane (6) is made of fabric.

9. Coating element according to any one of the preceding claims, wherein said lower internal membrane (5) is coupled with permanent fixing to said lower membrane (2) and / or wherein said upper internal membrane (6) is coupled with permanent fixing to said upper membrane (3).

10. Coating element according to claim 9, wherein said lower internal membrane (5) is glued to said lower membrane (2) and / or wherein said upper internal membrane (6) is glued to said upper membrane (3).

11. Coating element according to claim 10, wherein: said lower internal membrane (5) is made of polypropylene, said lower membrane (2) is made of polyvinyl chloride, and said lower internal membrane(5) is glued to said lower membrane (2) using a polyurethane-based glue; and / or said upper internal membrane (6) is made of polypropylene, said upper membrane (3) is made of polyvinyl chloride, and said upper internal membrane(6) is glued to said upper membrane (3) using a polyurethane-based glue.

12. Coating element according to any one of the preceding claims, wherein said lower and upper internal membranes (5 and 6) are joined together along an edge zone to form a bag which can contain ballast material.

13. Coating element according to any one of the preceding claims, wherein said lower membrane (2) is divided into two or more lower membrane portions (2a, 2b, ...) welded together and said lower internal membrane (5) is divided into two or more lower internal membrane portions (5a, 5b, ...), one side of each lower internal20250517 WO ENmembrane portion (5a, 5b, ...) being coupled with an upper side of a respective lower membrane portion (2a, 2b , . . .).

14. Coating element according to any one of the preceding claims, wherein said upper membrane (3) is divided into two or more upper membrane portions (3a, 3b, ...) welded together and said upper internal membrane (6) is divided into two or more upper internal membrane portions (6a, 6b, ...), one side of each upper internal membrane portion (6a, 6b, ...) being coupled with a lower side of a respective upper membrane portion (3a, 3b , . . .).

15. Coating element according to any one of the preceding claims, comprising two lateral closing elements (9) arranged on two respective lateral edge areas of said coating element (1), each of said two lateral closing elements (9) being configured to form a loop to laterally close said coating element (1).

16. Coating element according to claim 15, wherein at least one of said two lateral closing elements (9) comprises a lateral closing membrane (10) and an internal lateral closing membrane (11), said internal lateral closing membrane (11) comprising a membrane side coupled with an internal side of said lateral closing membrane (10), a lower end of said lateral closing membrane (10) being connected with said lower membrane (2) and an upper end of said lateral closing membrane(10) being connected with said upper membrane (3).

17. Coating element according to claim 16, wherein said lateral closing membrane (10) comprises a geomembrane and / or wherein said internal lateral closing membrane(11) is made of fabric.

18. Coating element according to any one of the preceding claims, comprising two joining wings (12) arranged on two respective lateral areas of said coating element (1) extended in a longitudinal direction and opposite each other, said watertight joining device (4) being arranged on said joining wings (12), each of said joining wings (12) being connected to at least one of said lower and upper membranes (2 and 3); each of said joining wings (12) comprising, in particular, a geomembrane.

19. Coating element according to claim 18 and according to any one of claims 15 to 17, wherein, for each of said two lateral areas, the respective joining wing (12) has an end coupled to a respective lateral closing element (9).

20. Coating element according to any one of the preceding claims, wherein said lower20250517 WO ENmembrane (2) comprises a geomembrane and / or said upper membrane (3) comprises a geomembrane.

21. Coating element according to any of the preceding claims, comprising a protective layer (13) coupled to a lower side of said lower membrane (2); said protective layer (13) being made, in particular, of geotextile, for example non-woven polypropylene geotextile.

22. Coating element according to any one of the preceding claims, wherein said watertight joining device (4) comprises a zipper, whereby said coating element (1) has two lateral areas extending in a longitudinal direction and opposite each other, on each of which a respective toothed band (4a) of said zipper is arranged.

23. Method of manufacturing a coating element, in particular according to claim 1, comprising the following steps: coupling one side of a first fabric membrane (5) with one side of a first geomembrane (2); coupling one side of a second fabric membrane (6) with one side of a second geomembrane (3); and coupling two opposite lateral edges of said first geomembrane (2) with two opposite lateral edges of said second geomembrane (3) so that said first fabric membrane (5) and said second fabric membrane (6) are arranged facing each other to define a ballast chamber (7) suitable for receiving ballast material; said method comprising, in particular, the step of attaching two toothed bands (4a) of a watertight zipper to two lateral areas of said covering element (1).

24. Manufacturing method according to claim 23, comprising the step of forming two lateral closing elements (9) respectively on said two lateral areas, at least one of said lateral closing elements (9) being formed by coupling one side of a lateral closing internal membrane (11) with an internal side of a lateral closing membrane (10) and coupling two opposite ends of said lateral closing membrane (10), respectively, with said first geomembrane (2) and with said second geomembrane (3) so that said lateral closing element (9) forms a lateral closing loop.

25. Waterproof coating for a waterbed, said coating comprising a plurality of coating elements (1) made according to any one of claims 1 to 22, arranged side by side and joined together, said coating comprising, for each of said coating elements (1), a ballast inserted into the respective ballast chamber (7).20250517 WO EN

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