Method for coating an inner side of a container

Abstract

The invention relates to a method for coating the inside of a wall (1) of a container (3), wherein at least one layer in the form of a balloon (2) is applied, wherein the balloon (2) is inserted in a folded state through an opening (4) of the container (3), and wherein the balloon (2) is subsequently inflated so that it adheres to the inside of the wall (1) of the container (3).

Description

[0001] The invention relates to a method for coating an inner wall of a container.

[0002] The invention is based on the objective of providing a novel method for coating the inside of a container wall.

[0003] The problem is solved according to the invention by a method having the features of claim 1.

[0004] Advantageous embodiments of the invention are the subject of the dependent claims.

[0005] A method is proposed for coating the inside of a container wall, wherein at least one layer in the form of a balloon is applied, the balloon being inserted in a folded state through an opening in the container, the balloon subsequently being pneumatically or hydraulically expanded so that it adheres to the inside of the container wall.

[0006] The opening of the container can be smaller than 10 cm, for example.

[0007] The balloon can, for example, be self-supporting and, in particular, has no supporting frame.

[0008] In one embodiment, the balloon is subsequently filled, optionally after emptying a liquid used for expansion, with small solids without sharp edges, in particular spheres, and the container with the solids is moved so that the balloon lies against the wall as completely as possible without leaving air bubbles between the wall and the balloon.

[0009] In one embodiment, the balloon has at least one layer of a metal foil, for example an aluminum, copper, nickel, silver, or gold foil, or a polymer foil coated with a metal, for example an aluminum, copper, or gold-coated polymer foil.

[0010] In one embodiment, the metal or polymer film has a maximum thickness of 0.7 mm. This prevents the film from collapsing and reducing the container's volume. Furthermore, using the thinnest possible film keeps the container's weight to a minimum.

[0011] In one embodiment, the balloon lacks a spacer layer on its outer surface facing the container wall, in particular a spacer layer with nubs or an air-permeable fleece. A spacer layer has the disadvantage that gases stored in the container, especially embrittled gases such as hydrogen or methane, can accumulate in it, adhere to the surface of the container (e.g., made of steel), dissociate, penetrate the wall, and embrittle it.

[0012] In one embodiment, the balloon further comprises at least one polymer layer and / or composite layer.

[0013] The polymer layer may, for example, contain a polyamide, polyethylene terephthalate, polyethylene or high-density polyethylene, polypropylene, polyamide, polyimide, polysulfone, polyvinyl chloride, polyvinyl fluoride, and / or polyvinylidene difluoride. Furthermore, the polymer layer may contain a polymer blend of several polymers, particularly those mentioned above, or a resin system, such as an epoxy resin.

[0014] The at least one composite layer, or at least one of the composite layers, can be formed from a polymer, polymer blend, or resin system (in particular as described above for the polymer layer) and a metal, semimetal, or metal alloy, especially the metal used in the metal foil or the metal-coated polymer foil. The metal can be, for example, Ag, Al, Au, Ge, Cu, and / or Ni, or an alloy of several of these materials. The polymer-metal composite layer can, for example, be based on an aluminum-containing lacquer.

[0015] The at least one composite layer, or at least one of the composite layers, can be formed from a polymer, polymer blend, or resin system (in particular as described above for the polymer layer) and an oxide material, for example, glass, ceramic, metal oxide, and / or mica. The polymer-oxide composite layer can, for example, be a flexible polymer with embedded platelet-shaped oxide pigments (e.g., mica).

[0016] The polymer layer or the composite layer can be formed, for example, by filling the balloon with a liquid used to expand it, then emptying and drying it.

[0017] Before inserting the balloon into the opening, a primer and / or a polymer coating can be applied to the inside of the wall to improve the adhesion of the balloon to the wall.

[0018] In one embodiment, the wall or container can be heated before the balloon expands in the container to improve the adhesion of the balloon to the wall and / or to the primer and / or to the polymer coating.

[0019] According to one aspect of the present invention, a container, for example with a wall made of steel, is proposed which is coated by means of the method described above.

[0020] In particular, it may be stipulated that the container is not made of fiber composite materials.

[0021] The container can be used, for example, to store embrittled gases, such as hydrogen or methane, or gas mixtures under pressure, for example, from 300 bar to 1000 bar. It is known that high hydrogen pressures, in particular, lead to embrittlement, especially of hardened steels, which can cause the pressure vessel to burst. A likely mechanism discussed is the diffusion of atomic hydrogen from the metal surface into the steel. Recombination to form molecular hydrogen within the metal lattice disrupts the metal structure and leads to embrittlement.

[0022] The container, due to the internal coating applied according to the invention, has a barrier layer to prevent steel embrittlement caused by hydrogen or other embrittlement gases (for example, methane), thereby enabling a reduction in wall thickness. The pressure vessel can be used in hydrogen technology, particularly for hydrogen transport, as well as in stationary hydrogen storage systems, for example in the energy sector or as a container for hydrogen-powered road or rail vehicles, especially in freight transport.

[0023] The pressure vessel can be a gas cylinder or a pipeline.

[0024] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0025] It shows: Figure 1 is a schematic view of a partially unfolded balloon, Figure 2 is a schematic view of the folded balloon, Figure 3 is a schematic view of a pressure vessel with an opening and the balloon inserted therein, Figure 4 is a schematic view of the pressure vessel with an opening and the balloon inserted therein while it is pneumatically or hydraulically expanded and unfolds, and Figure 5 is a schematic view of the pressure vessel with the opening and the inserted balloon when it is fully inflated.

[0026] Corresponding parts are marked with the same reference symbols in all figures.

[0027] Figure 1Figure 2 shows a partially unfolded balloon 2 for applying a coating to the inside of a wall 1 of a container 3, for example a pressure vessel 3, particularly for storing hydrogen or methane. The balloon 2 is initially folded so that it fits through an opening 4 of the pressure vessel 3. Figure 2 is a schematic view of the folded balloon 2.

[0028] Figure 3 Figure 1 is a schematic view of the pressure vessel 3 with an opening 4 through which the balloon 2 is inserted. Figure 4 Figure 3 is a schematic view of the pressure vessel 3 with the opening 4 and the inserted balloon 2 while it is being inflated and unfolding. Figure 5Figure 3 is a schematic view of the pressure vessel 3 with the opening 4 and the inserted balloon 2, which is fully inflated so that it presses against the inner wall 1 of the pressure vessel 3. Optionally, the balloon 2 can then be filled with small solids without sharp edges, for example, spheres, and the pressure vessel 3 can be moved with the solids inside so that the balloon 2 presses against the wall 1 as completely as possible, without any air bubbles remaining between the wall 1 and the balloon 2. The balloon 2 can have one or more layers. For example, the balloon 2 can be made of aluminum foil. In another embodiment, the balloon 2 can have an aluminum foil and a polymer layer, or an aluminum foil, a polymer layer, another aluminum foil, and another polymer layer.In one embodiment, the balloon 2, when inflated, has a shape that corresponds to an inner shape of the pressure vessel 3.

[0029] Before inserting the balloon 2 into the opening 4, a primer and / or a polymer coating may be applied to the inside of the wall 1 to improve the adhesion of the balloon 2 to the wall 1. It may also be possible to heat the wall 1 or the container 3 before inflating the balloon 2 in the container 3 to further improve the adhesion of the balloon 2 to the wall 1 and / or to the primer and / or the polymer coating.

[0030] Container 3 may be equipped with a residual pressure valve to prevent the balloon 2 from collapsing inside container 3. LIST OF REFERENCE SYMBOLS

[0031] 1. Wall 2. Balloon 3. Pressure vessel 4. Opening

Claims

1. A method for coating an inner side of a wall (1) of a container (3), wherein at least one layer in the form of a balloon (2) is applied, wherein the balloon (2) is introduced in a folded state through an opening (4) of the container (3), wherein the balloon (2) is then expanded pneumatically or hydraulically so that it adheres to the wall (1) of the container (3) from the inside.

2. Method according to claim 1, wherein the balloon (2) is subsequently filled with small solid bodies without sharp edges, in particular spheres, and the container (3) with the solid bodies is moved.

3. Method according to claim 1 or 2, wherein the balloon (2) has at least one layer of a metal foil, in particular an aluminum foil, a copper foil, a nickel foil, a silver foil, a gold foil or a metal-coated polymer foil, for example an aluminum-, copper- or gold-coated polymer foil.

4. The method according to claim 3, wherein the balloon (2) further comprises at least one polymer layer and / or composite layer.

5. The method according to claim 4, wherein the polymer layer and / or composite layer comprises at least one of the polymers polyamide, polyethylene terephthalate, polyethylene or HD-polyethylene, polypropylene, polyamide, polyimide, polysulfone, polyvinyl chloride, polyvinyl fluoride and / or polyvinylidene difluoride, a polymer blend of several of the said polymers, or a resin system, in particular an epoxy resin.

6. The method according to claim 5, wherein the composite layer further comprises a metal or semi-metal or a metal alloy or semi-metal alloy and / or an oxide material.

7. A method according to any one of claims 4 to 6, wherein the polymer layer or the composite layer is formed by filling a liquid used to expand the balloon, then emptying and drying.

8. Method according to one of the preceding claims, wherein a primer and / or a polymer coating is / are applied to the inside of the wall (1) before the balloon (2) is introduced into the opening (4).

9. Method according to one of the preceding claims, wherein the wall (1) or the container (3) is heated before inflating the balloon (2) in the container (3).

10. A method according to any one of the preceding claims, wherein the balloon is self-supporting.

11. Container (3) coated by means of the method according to one of the preceding claims.

12. Container (3) according to claim 11, comprising a wall (1) made of steel with an opening (4).

13. Container (3) according to claim 12, wherein the opening (4) has a diameter of less than 10 cm.

14. Use of the container (3) according to one of claims 11 to 13 for storing embrittling gases, in particular hydrogen or methane, or gas mixtures under pressure.

15. Use according to claim 14, wherein the pressure is in the range of 300 bar to 1000 bar.

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