FR3037633A1 - COMPOSITE TANK AND METHOD OF MONITORING AND REPAIRING - Google Patents

Abstract

Composite reservoir (1) for storing fluid under pressure and its control method, the reservoir having a wall structure comprises, from the inside to the outside of the reservoir, a sealed internal envelope (2) intended to be in contact with the fluid under pressure, a first reinforcing layer (3) disposed on the inner casing (2), at least one protective layer (4, 5, 6) disposed on the first reinforcing layer (3), the first layer Reinforcement (3) comprising a fiber-based and resin-based structure, the at least one protective layer (4, 5, 6) comprising at least one of: a layer (4) of shock absorbing material, a layer of fire resistant material, a layer (6) based on fibers and resin, characterized in that the first reinforcing layer (3) incorporates or is covered with a color change color marker when subjected to at a certain threshold temperature.

Description

The present invention relates to a composite tank and a method for controlling and repairing tank (s). The invention more particularly relates to a composite reservoir for storing pressurized fluid, especially pressurized gas, having a wall structure comprising, from the inside to the outside of the tank, a sealed inner envelope intended to be in contact with the fluid under pressure, a first reinforcing layer disposed on the inner casing, at least one protective layer disposed on the first reinforcing layer, the first reinforcing layer comprising a fiber-based structure and resin, the at least one a protective layer comprising at least one of: a shock-absorbing material layer, a fire-resistant material layer, a fiber-resin layer. A composite reservoir is generally composed of a metal or polymeric inner shell (also called liner) coated with a composite reinforcement and a generally metallic base. The base can also be plastic, for example molded in the same material as the liner. The role of the liner is to seal the stored gas. The composite reinforcement, formed of reinforcing fibers and resin, serves to ensure the resistance to the pressure of the tank.

In order to provide mechanical protection, a composite reinforcement based on aramid glass fibers or the like is generally wound directly on the structural part of the reinforcement. When a composite tank has been exposed to high temperatures (fire ...) or shocks, its mechanical integrity may be impaired without this being visible. This can be the source of important safety problems because this type of tank can store gas at high pressures, for example up to 1000 bar. An object of the present invention is to overcome all or part of the disadvantages of the prior art noted above.

An object of the invention may in particular be to provide a reservoir for easily and reliably identifying whether a repair of the tank is necessary or if the use of the tank for storing high pressure must be avoided.

For this purpose, the tank according to the invention, moreover, conforming to the generic definition given in the preamble above, is essentially characterized in that the first reinforcing layer incorporates or is covered with a chromatic marker. at color change when subjected to a predetermined threshold temperature. Furthermore, embodiments of the invention may include one or more of the following features: the chromatic marker of the first reinforcing layer comprises at least one of: thermochromic pigments, leuco dyes integrated with the resin of the first reinforcing layer, at least one sheet adhered to the first reinforcing layer and comprising a color change marker when it is subjected to a predetermined threshold temperature, the at least one protective layer comprises at least one least one of: a layer of shock absorbing elastomeric material, a felt layer, a layer of silica fibers, a layer of glass fabrics, or generically any other insulating material, - the reservoir comprises, arranged on the first reinforcing layer of the inside to the outside of the tank, a layer of shock-absorbing and / or resistant material, a a resin-impermeable shell and a second reinforcing layer comprising a fiber-based and resin-based structure; - the second reinforcing layer incorporates or is covered with a color change color marker when subjected to a temperature limit determined and / or a determined intensity shock, the inner envelope comprises or consists of metal or plastic, in particular polymer with optionally one or more additives, adjuvants and / or a filler, the first reinforcing layer comprises a structure based on glass fibers and / or carbon and thermoplastic or thermosetting resin, in particular of the epoxy type, - the reservoir comprises, at least, a metal, plastic or charged plastic base on which is fixed the wall of the tank so as to delimit, at least, a filling and withdrawal orifice, the invention may also relate to any device or process alternative comprising any combination of the features above or below. The invention also relates to a method for controlling and repairing at least one composite tank whose wall comprises, from the inside towards the outside of the tank, a sealed internal envelope intended to be in contact with the fluid under pressure. a first reinforcing layer disposed on the inner casing, a protective layer disposed on the first reinforcing layer, a resin impermeable casing and a second reinforcing layer, the first reinforcing layer comprising a base-forming structure; fibers and resin, the protective layer comprising at least one or a combination of: a layer of shock-absorbing material, a layer of fire-resistant material; the second reinforcing layer comprising a fiber-based and resin-based structure, wherein the first reinforcing layer incorporates or is covered with a color change color marker when subjected to a determined threshold temperature and the second reinforcing layer incorporates or is covered by a color marker with a determined color change distinct from the color of the marker of the first reinforcing layer when it is subjected to a determined temperature and / or a determined impact, the method comprising an inspection to determine if only the color marker of the second reinforcing layer indicates changed color or if the color marker of the first reinforcing layer has also changed color. According to other possible features: - when only the determined color change color marker of the second reinforcing layer has changed color, the method comprises a step of removing and replacing the second reinforcing layer, the envelope impervious and shock absorbing material layer and / or heat resistant, - when the color marker of the first reinforcing layer has changed color indicating exposure to the determined threshold temperature, the reservoir is discarded.

Other features and advantages will appear on reading the following description, with reference to the figures in which: - Figure 1 shows a longitudinal sectional view, schematic and partial, illustrating an example of a structure of a tank according to the invention. FIG. 2 diagrammatically and partially illustrates a detail of the wall of the tank of FIG. 1; FIG. 3 is a diagrammatic and partial representation of a section of the section of a tank according to another embodiment. Figures 1 and 2 illustrate an example of a composite tank structure 1 having a base 7. The structure of the tank 1 comprises an inner casing 2 (liner). This liner 2 is for example made of polymer and may have a thickness of preferably between 2 and 10 mm (the thickness may vary depending on the volume of the tank). This liner 2 is coated with a composite structuring part, in particular a first reinforcing layer 3 placed on the liner 2. Traditionally, this reinforcing layer 3 is composed of a mixture of fibers (glass and / or carbon) embedded in a resin, for example epoxy. This layer may have a thickness of between 2 and 200 mm. This thickness may depend on the pressure of the stored gas, the orientation of the reinforcing fibers and the considered safety factor. This first reinforcing layer 3 comprises a maximum temperature detection system (see minimum if any) to which the layer is exposed. This temperature detection system comprises, for example, an integrated color marker or bonded to said layer 3. For example, a heat-sensitive tape is bonded to the reinforcing layer 3 to indicate the maximum / minimum temperature reached by this layer. For example, the following devices may be referred to: self-adhesive tapes of the brand "THERMAX" or "TESTOTERM". The tank 1 then comprises at least one layer 4 of protection material (x) damping (s) and / or fire resistant (eg elastomers, felt, silica fibers, ...). This or these protective layers 4 have for example a thickness of between 2 and 100 mm (function desired performance). In this way, this protective layer 4 has a thickness sufficient to allow it to be cut (for example to the diamond disk 8, see FIG. 1) in order to remove it without damaging the structuring part 2, 3 inside. An impermeable (and / or heat-shrinkable) jacket or sheath 5 is then disposed on these materials. The envelope 5 is for example composed of resin-impermeable and / or heat-shrinkable materials and may have a thickness of between 0.15 and 2 mm. This envelope ensures the maintenance of the layers it encompasses and forms a barrier for the resin of the next layer which will coat it.

On this casing 5, the reservoir 1 comprises a second reinforcing layer 6 (resin and fibers for example) preferably having a thickness of between 0.2 and 10 mm. This second reinforcing layer 6 is preferably also provided with a chromatic marker, which upon impact (shock) will produce a visible surface color change either with the naked eye or with an external means (lamp UV, ...) making it visible to the naked eye. The chromatic markers of the first 3 and second 6 reinforcement layers preferably have distinct colors and colorations that occur at different energy levels.

This can be used during a tank inspection step during a return to the factory before possible reuse of the tank 1. Thus, during a relatively "slight" damage to the tank, only the outer layer 6 is damaged (blue color appears for example during a visual inspection).

In case of relatively greater damage, the structuring part (first reinforcement layer 3) is damaged and damaged (the red color for example appears). In the first case, the outer protection (layers 4, 5, 6) can be removed and replaced by new layers disposed on the first reinforcing layer 3. In the second case, if the internal structuring part (first reinforcing layer 3) is damaged, the security is no longer ensured and the reservoir can be removed from the use circuit (waste, destruction, recycling ...).

In particular, when the tank has been exposed to fire, the outer layers 6, 5, 4 are removed to know the impact on the first reinforcing layer 3. If the maximum temperature at which the latter has been exposed exceeds a threshold which depends on the nature of the reinforcing fibers and the resin used (for example 100 ° C. depending on the chemical nature of the resin - indicated by the chromatic marker or the maximum temperature sensor of the thermochromic ribbon type), this may indicate that the integrity of the structure is reached and that the reservoir is not reusable. In the opposite case (no threshold temperature reached), the tank 1 can be coated again with outer layers. The reinforcement layer or layers 3, 6 may be made of thermoplastic composite material (fiberglass / thermoplastic resin) added with chromatic markers. The advantage of thermoplastic composites is that they have better impact resistance than thermosetting composites and that their resin has a lower density than thermosets (Epoxy type). Preferably, this first reinforcing layer 3 is entirely polymerized (in the case of the thermosetting resin) before coating it with the following layer 4 (in the case of a thermoplastic resin winding, no polymerization is required).

Temperature-sensitive color markers may be of the type used in thermochromatic paints. Alternatively, a "paper" or heat-reactive fabric may be bonded to the structure (layers 3, 6) to indicate the maximum and / or minimum temperature at which the structure has been exposed.

In the case where the tank 1 is in contact with the fire, the intermediate protective layer 4 will ensure a minimum holding of the fire reservoir (minimum duration determined). Once the outer composite layer 6 has been removed with suitable means, any overexposure to the temperature of the internal composite structure 3 can be identified either by coloring the resin or by visualizing the temperature reached on the thermal paper. Of course, the invention is not limited to the example described above. Thus, additional protective layers 4 or reinforcement 3, 6 can be provided. Similarly, layers can be omitted. In the example of FIG. 3, the wall comprises only a protective layer 4 (damping / fire resistance) on the first reinforcement layer 3.

Claims (11)

REVENDICATIONS1. Composite tank (1) for storing pressurized fluid, in particular pressurized gas, having a wall structure comprising, from the inside towards the outside of the tank, a sealed internal envelope (2) intended to be in contact with the fluid under pressure, a first reinforcing layer (3) disposed on the inner casing (2), at least one protective layer (4, 5, 6) disposed on the first reinforcing layer (3), the first layer (3), 3) comprising a fiber and resin-based structure, the at least one protective layer (4, 5, 6) comprising at least one of: a layer (4) of shock-absorbing material, a layer of fire-resistant material, a layer (6) based on fibers and resin, characterized in that the first reinforcing layer (3) incorporates or is covered with a color change color marker when subjected to a threshold temperature determined. 2. Tank according to Claim 1, characterized in that the chromatic marker of the first reinforcing layer (3) comprises at least one of: thermochromic pigments, leuco dyes incorporated in the resin of the first layer (3) reinforcement, at least one sheet adhered to the first reinforcing layer (3) and comprising a color change color marker when subjected to a predetermined threshold temperature. 3. Tank according to claim 1 or 2, characterized in that the at least one layer (4, 5, 6) of protection comprises at least one of: a layer of shock-absorbing elastomeric material, a felt layer, a layer of silica fibers, a layer of glass fabrics. 4. Tank according to any one of claims 1 to 3, characterized in that it comprises, disposed on the first layer (3) of reinforcing the interior towards the outside of the tank, a layer (4) of material shock absorbent and / or resistant, a resin impervious casing (5) and a second reinforcing layer (6) comprising a fiber-based and resin-based structure. 3037633 9 5. Tank according to Claim 4, characterized in that the second reinforcing layer (6) incorporates or is covered with a color change color marker when it is subjected to a determined limit temperature and / or a shock of determined intensity. 5 6. Tank according to any one of claims 1 to 5, characterized in that the inner casing (2) comprises or consists of metal or plastic, in particular polymer with optionally one or more additives, adjuvants and / or charge. 7. Tank according to any one of claims 1 to 6, characterized in that the first layer (3) of reinforcement comprises a structure based on glass fibers and / or carbon and thermoplastic resin or thermosetting, in particular epoxy type. 8. Tank according to any one of claims 1 to 7, characterized in that it comprises a base (7) metal, plastic or plastic loaded on which is fixed the wall of the tank (1) so as to define an orifice filling and racking. 9. A method for controlling and repairing at least one composite tank whose wall comprises, from the inside to the outside of the tank, a sealed internal envelope (2) intended to be in contact with the fluid under pressure, a first reinforcing layer (3) disposed on the inner casing (2), a protective layer (4, 5, 6) disposed on the first reinforcing layer (3), a casing (5) impervious to the resin and a second reinforcing layer (6), the first reinforcing layer (3) comprising a fiber-resin structure, the protection layer (4, 5, 6) comprising at least one or a combination of a layer (4) of shock-absorbing material, a layer of fire-resistant material; the second reinforcing layer (6) comprising a fiber-resin structure, wherein the first reinforcing layer (3) incorporates or is covered by a color change color marker when subjected to a predetermined threshold temperature and the second reinforcing layer (6) incorporates or is covered by a determined color change color marker distinct from the color of the marker of the first reinforcing layer (3) when subjected to a determined temperature and / or a determined shock, the method comprising a visual inspection to determine if only the color marker of the second reinforcing layer (6) indicates changed color or the chromatic marker of the first layer (3) reinforcement has also changed color. The method according to claim 9, characterized in that when only the determined color change color marker of the second reinforcing layer (6) has changed color, the method comprises a step of removing and replacing the second reinforcing layer (6), the impermeable envelope (5) and the layer (4) of shock-absorbing and / or heat-resistant material. 11.Procédé according to claim 9 or 10, characterized in that when the chromatic marker of the first (3) reinforcing layer 15 has changed color indicating an exposure to the determined threshold temperature, the reservoir (1) is scrapped .