Reservoir made of pultruded cylindrical elements

Abstract

The present invention relates to a tank for containing a pressurized fluid, comprising: at least one cylindrical element made of a pultruded fiber material impregnated with a thermoplastic matrix; a first cap arranged at one end of the at least one cylindrical element and closing it; a second cap arranged at the other end of the at least one cylindrical element and fitted with an orifice intended to allow the entry and exit of a fluid; at least one additional fiber reinforcement partially or completely surrounding the cylindrical element and optionally the cap; Including, the fibers in the additional fiber reinforcement are arranged along an axis different from the longitudinal axis of the cylindrical element; the total fiber content of the tank is between 40% and 70% by volume relative to the volume of matrix and the volume of fibers contained in the tank; The present invention relates to a tank for containing a pressurized fluid.

Description

[Technical field]

[0001]

[0001] The present invention relates to a tank intended to contain a fluid under pressure. The invention also relates to a method for its manufacture and further to its use for storing, transporting and / or distributing a fluid, in particular hydrogen. [Background technology]

[0002]

[0002] Currently, the ecological transition tends to reduce petroleum consumption and promote the use of less polluting forms of energy. From this point of view, hydrogen is one of the fluids that is being particularly studied. In particular, fuel cell vehicles have proven to be the subject of many studies.

[0003]

[0003] In this field, one of the difficulties with regard to the mass production of such vehicles is the design of the tank, since the hydrogen tanks installed in these vehicles are subject to operating pressures, which can reach up to 700 bar, and must meet important safety requirements in order to limit as much as possible the consequences of a collision, an accidental impact or a fire. For example, if the tank is damaged in an accident involving the vehicle, or if a projectile fired from a firearm passes through it, it is desirable for the tank to gradually release pressure without exploding or rupturing significantly. The same applies if a fire in the vehicle causes an increase in the temperature of the gas in the tank.

[0004] An important advantage is the ease of insertion into the vehicle body, and particularly the battery pack, to replace all or part of the battery.

[0005] Another object is to make such tanks commercially available at a reasonable cost, for example a cost acceptable for automotive applications.

[0006] Furthermore, the pressure constraints required for hydrogen tanks mean that, from a mechanical point of view, other chemically non-aggressive fluids can be placed in such tanks.

[0007]

[0007] A tank for storing fluids under high pressure, having a cylindrical overall shape and a circular cross section, which comprises, at each end along its axis, a metal cap, a liner surrounding said cap and a structural layer made of fibers impregnated with a thermosetting resin surrounding said liner, is known from document FR 2 923 575.

[0008]

[0008] A tank made of a composite material is known from document WO 2017 / 199193, which comprises a tubular element, two caps respectively inserted at the ends of the tubular element, and a peripheral layer surrounding the tubular element and the caps. The peripheral layer is formed by winding fibers impregnated with resin. The tubular element essentially comprises a plastic tube surrounded by a longitudinal layer of parallel-arranged fibers in a resin matrix, the parallel fibers being oriented in the direction of the longitudinal axis of the plastic tube.

[0009]

[0009] These "conventional" composite gas storage tanks typically have an internal cylindrical diameter of 150 mm or more for volumes greater than 10 litres.

[0010]

[0010] Conversely, "compatible" or "polymorphic" gas storage tanks generally consist of an assembly of closed pipes connected together. These polymorphic tanks are manufactured by assembling composite pipes of small diameter, usually less than 150 mm inside diameter.

[0011]

[0011] However, the optimal technical solutions for efficiently manufacturing storage tanks of this kind, especially hydrogen storage tanks under high pressure, are not yet well defined.

[0012]

[0012] Closing a tube with a cap which may have the shape of a hemispherical dome requires that the fibres be positioned, ideally inserted on the axis of the tube, to maintain these domes; however, taking into account the hemispherical shape of the domes, the fibres cannot be strictly aligned with the axis of the tube, which would be detrimental to their effectiveness, and if they were in fact aligned along the axis of the tube, it would be necessary to use more of them than the strict minimum amount which could be envisaged.

[0013]

[0013] Furthermore, when the diameter of the tube becomes too small, usually less than 150 mm, it becomes complicated to close the tube with a dome having a radius of curvature large enough that problems do not arise when winding the fiber around the tank.

[0014] Furthermore, the production rates of these tubes are relatively slow and involve the manufacture of a liner, then winding one or more specific fibers around this liner, and closing the tube.

[0015]

[0015] Finally, the most common composite tank solution uses composite reinforcements of thermosetting resin, especially epoxy type. In practice, these composite materials generally suffer from microcracks, so that the use of thick and heavy liners is essential to ensure the tightness of the tank. Microcracks in thermosetting composites, especially epoxies, are detrimental to the mechanical strength, necessitating an increase in the carbon fiber content, thus increasing the cost of the tank.

[0016]

[0016] This drawback is combined with another when the composite reinforcement is produced by wet filament winding, since this type of process leads to a high degree of porosity due to the lack of high pressures during the process.

[0017] Finally, composite tanks based on thermosetting resins, especially epoxy resins, cannot be recycled.

[0018]

[0018] Therefore, what is needed is a tank that can withstand high pressures, is relatively easy to manufacture, and is recyclable.

[0019] The present invention relates to a method for producing a at least one cylindrical element made of a pultruded fiber material impregnated with a thermoplastic matrix; a first cap arranged at one end of the at least one cylindrical element and closing it; a second cap arranged at the other end of the at least one cylindrical element and fitted with an orifice intended to allow the entry and exit of a fluid; at least one additional fiber reinforcement partially or completely, preferably completely, surrounding the cylindrical element and optionally the cap; Including, the fibers in the additional fiber reinforcement are positioned on an axis different from the longitudinal axis of the cylindrical element; the total fiber content of the tank is between 40% and 70% by volume relative to the volume of matrix and the volume of fibers contained in the tank; The present invention relates to a tank for containing a pressurized fluid.

[0020] The present invention also relates to a method for manufacturing a tank as defined above, said method comprising the steps of: (a) pultrusion of a cylindrical element; (b) placement of caps on the ends of the cylindrical element obtained at the end of step (a); (c) the step of depositing additional fiber reinforcement; The method is characterized in that it comprises the successive steps of:

[0021]

[0021] Finally, the present invention relates to the use of a tank as defined above for the storage, transportation and / or distribution of fluids such as gases in compressed, liquid or cryogenically compressed form, in particular hydrogen, natural gas, LPG, LNG, compressed air, nitrogen or oxygen. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 shows a manufacturing process for a cylindrical element made of pultruded fiber material impregnated with a thermoplastic matrix containing additional fiber reinforcement for a tank according to the invention. [Diagram 2]

[0023] 5A-5C show another manufacturing process for a cylindrical element made of pultruded fiber material impregnated with a thermoplastic matrix containing additional fiber reinforcement for a tank according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023]

[0024] Other features, aspects, objects and advantages of the present invention will become more clearly apparent from a reading of the following description.

[0024]

[0025] It is expressly stated that the expressions "from...to..." and "of between...and..." used in this description are to be understood as including each of the limitations referred to.

[0025] tank

[0026] The tank according to the invention comprises: at least one cylindrical element made of a pultruded fiber material impregnated with a thermoplastic matrix; a first cap arranged at one end of the at least one cylindrical element and closing it; a second cap arranged at the other end of the at least one cylindrical element and fitted with an orifice intended to allow the entry and exit of a fluid; at least one additional fiber reinforcement partially or completely, preferably completely, surrounding the cylindrical element and optionally the cap; Including, the fibers in the additional fiber reinforcement are positioned along an axis different from the longitudinal axis of the cylindrical element; The total fibre content of the tank is between 40% and 70% by volume relative to the volume of matrix and the volume of fibres contained in the tank.

[0026]

[0027] The cylindrical elements are manufactured according to the pultrusion process. They therefore consist of fibers impregnated with a thermoplastic matrix. Pultrusion is generally a continuous process, applying a traction force to the fibers along the axis of the cylindrical element through a die, but the fibers are not necessarily oriented in the traction axis. Pultrusion covers the impregnation of dry fibers, for example braids of dry fibers, fabrics of dry fibers or unidirectional rovings. It also covers the processing in the form of profile elements of co-blended fibers, pre-impregnated fibers, braids pre-impregnated with resin. According to the latter case, the fibers can be pre-impregnated before the pultrusion stage.

[0027]

[0028] Generally, prior art tubes consist of a tube called "liner" which is then covered with fibres. In fact, the tank according to the invention comprises a cylindrical element which already comprises fibres. This aspect of the tank according to the invention is very advantageous, since the manufacture of the cylindrical element by pultrusion is highly productive, even for thick elements, since the entire volume of the cylindrical element is produced in a continuous and single step. Furthermore, by incorporating fibres in the cylindrical element, it is possible to omit the deposition of a fibre reinforcement impregnated on the axis of the tube, since this deposition step is relatively slow and not always easy to control.

[0028]

[0029] According to one embodiment of the invention, and particularly depending on the type of fluid in question, the tank according to the invention may comprise a liner, which is however not essential.

[0029] fiber

[0030] As regards the constituent fibres of said fibre material, these are fibres of inorganic, organic or vegetable origin, especially in the form of rovings.

[0030]

[0031] Advantageously, the number of fibers per roving is, in the case of carbon fibers, 12K or more, 24K or more, in particular 50K or more, in particular between 24K and 36K.

[0031]

[0032] Advantageously, the basis weight of the glass fibres is, for each roving, greater than or equal to 1200 tex, in particular less than or equal to 4800 tex, in particular between 1200 and 2400 tex.

[0032]

[0033] Among the fibers of inorganic origin, mention may be made, for example, of carbon fibers, glass fibers, basalt or basalt-based fibers, silica fibers or silicon carbide fibers. Among the fibers of organic origin, mention may be made, for example, of fibers based on thermoplastic or thermosetting polymers, such as semi-aromatic polyamide fibers, aramid fibers or polyolefin fibers. Preferably, they are based on amorphous thermoplastic polymers and exhibit a higher glass transition temperature Tg than that of the constituent thermoplastic polymers or polymer blends of the impregnating matrix, if the polymer or polymer blend is amorphous or higher than the melting point of the constituent thermoplastic polymers or polymer blends of the impregnating matrix, if the polymer or polymer blend is semi-crystalline. Advantageously, they are based on semi-crystalline thermoplastic polymers and exhibit a higher melting point than that of the constituent thermoplastic polymers or polymer blends of the impregnating matrix, if the polymer or polymer blend is amorphous or higher than the melting point of the constituent thermoplastic polymers or polymer blends of the impregnating matrix, if the polymer or polymer blend is semi-crystalline. Thus, there is no risk of melting the constituent organic fibers of the fiber material during impregnation with the thermoplastic matrix of the final composite. Among the fibres of plant origin, mention may be made of natural fibres based on flax, hemp, lignin, bamboo, silk, especially spider silk, sisal and other cellulose fibres, in particular viscose fibres, which can be used in the pure state, treated or coated with a coating layer to promote adhesion and impregnation of the thermoplastic polymer matrix.

[0033]

[0034] It is also possible to use fibers with support yarns.

[0034]

[0035] These constituent fibers can be used alone or in admixture. Thus, organic fibers can be mixed with inorganic fibers to form an impregnated fibrous material impregnated with a thermoplastic polymer.

[0035]

[0036] Organic fiber rovings can have several basis weights and may also exhibit several geometric shapes.

[0036]

[0037] The fibres are provided in the form of continuous fibres and constitute 2D fabrics, non-woven fabrics (NCF), unidirectional (UD) fibres or non-woven braids or rovings. The constituent fibres of the fibre material may furthermore be in the form of a mixture of these reinforcing fibres of various shapes. Preferably, the fibres contained in the pultruded fibre material of the cylindrical element are braids of dry fibres.

[0037]

[0038] Preferably, the fiber material is selected from glass fibers, carbon fibers, basalt fibers and basalt-based fibers. According to a first advantageous embodiment, the fiber material is selected from glass fibers. According to a second advantageous embodiment, the fiber material is selected from carbon fibers. According to a third advantageous embodiment, the fiber material is selected from basalt-based fibers.

[0038]

[0039] Advantageously, the fibres are used in the form of a roving or multiple rovings.

[0039] Thermoplastic matrix

[0040] The term "thermoplastic" or "thermoplastic polymer" is understood to be a material that is generally solid at ambient temperature, which may be semi-crystalline or amorphous, and which, if amorphous, or if semi-crystalline, may show appreciable melting upon passing its "melting point" (Mp), softens during temperature increase and flows at higher temperatures, in particular after passing the glass transition temperature (Tg), which becomes solid again upon decreasing the temperature below the crystallization point (for semi-crystalline polymers) and the glass transition temperature (for amorphous polymers).

[0040]

[0041] The glass transition temperatures, hereinafter designated Tg, and the melting points, hereinafter designated Mp, are determined by differential scanning calorimetry (DSC) according to the ISO 11357-2:2013 and 11357-3:2013 standards, respectively.

[0041]

[0042] The thermoplastic polymer may be an amorphous polymer exhibiting a glass transition temperature Tg of 50°C or more, in particular 100°C or more, in particular 120°C or more, in particular 140°C or more, or it may be a semi-crystalline thermoplastic polymer with Mp greater than 150°C.

[0042]

[0043] The matrix is ​​described as "thermoplastic," which means that the major component of the matrix is ​​a thermoplastic polymer or a blend of thermoplastic polymers.

[0043] Advantageously, said at least thermoplastic polymer is a thermoplastic polymer selected from the group consisting of poly(aryl ether ketones) (PAEK), in particular poly(ether ether ketones) (PEEK); poly(aryl ether ketone ketones) (PAEKK), in particular poly(ether ketone ketones) (PEKK); aromatic polyetherimides (PEI); polyarylsulfones, in particular polyphenylene sulfones (PPSU); polyarylsulfides, in particular polyphenylene sulfide (PPS); polyamides (PA), in particular semi-aromatic polyamides (polyphthalamides), optionally modified with urea units; PEBA, among others, having a melting point above 150° C. polyacrylates, in particular polymethyl methacrylate (PMMA); polyolefins other than polypropylene; polylactic acid (PLA); polyvinyl alcohol (PVA); fluoropolymers, in particular polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); polyvinyl chloride (PVC) and acrylonitrile-butadiene-styrene (ABS) polymers and blends thereof, in particular blends of PEKK and PEI, preferably in an amount of 90-10% by weight to 60-40% by weight, in particular 90-10% by weight to 70-30% by weight.

[0044]

[0045] Advantageously, said at least thermoplastic polymer is chosen from polyamides, aliphatic polyamides, cycloaliphatic polyamides and semi-aromatic polyamides (polyphthalamides), PEKK, PEI and blends of PEKK and PEI.

[0045] The nomenclature used to define polyamides is described in standard NF EN ISO 1874-1:2011, "Plastics - Polyamide (PA) Moulding and Extrusion Materials - Part 1: Designation", in particular page 3 (Tables 1 and 2) and is well known to the person skilled in the art.

[0046]

[0047] The polyamide can be a homopolyamide, a copolyamide, or a blend thereof.

[0047]

[0048] For tanks which need to withstand high temperatures, poly(aryl ether ketone) PAEK, such as poly(ether ketone) PEK, poly(ether ether ketone) PEEK, poly(ether ketone ketone) PEKK, poly(ether ketone ether ketone ketone) (PEKEKK)) or PA with a high glass transition temperature Tg are advantageously used according to the invention.

[0048]

[0049] Advantageously, the polyamide is chosen from aliphatic polyamides, cycloaliphatic polyamides and semi-aromatic polyamides (polyphthalamides).

[0049]

[0050] Advantageously, the aliphatic polyamide is selected from polyamide 6 (PA6), polyamide 11 (PA11), polyamide 12 (PA12), polyamide 66 (PA66), polyamide 46 (PA46), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 11 / 1010 (PA11 / 1010) and polyamide 12 / 1010 (PA12 / 1010), or blends thereof or copolyamides thereof, and block copolymers, in particular polyamide / polyether (PEBA) copolymers, and the semi-aromatic polyamide is a semi-aromatic polyamide, optionally modified by urea units, in particular PA MXD6 and PA MXD10, or the polyamides according to EP 1 505 099, in particular semi-aromatic polyamides of the formula X / YAr, in particular semi-aromatic polyamides of the formula A / XT, -A is selected from units derived from amino acids, units derived from lactams and units corresponding to the formula (Ca diamine)·(Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b being each between 4 and 36, advantageously between 9 and 18, the (Ca diamine) units being selected from linear or branched aliphatic diamines, cycloaliphatic diamines and alkylaromatic diamines, and the (Cb diacid) units being selected from linear or branched aliphatic diacids, cycloaliphatic diacids and aromatic diacids; -XT represents a unit resulting from the polycondensation of a Cx diamine (wherein x represents the number of carbon atoms of the Cx diamine, x being between 6 and 36, advantageously between 9 and 18) with terephthalic acid (T). Advantageously, the semi-aromatic polyamide is of formula A / 6T, A / 9T, A / 10T or A / 11T, where A is as defined above, and in particular is a polyamide PA6 / 6T, PA66 / 6T, PA6I / 6T, PAMPMDT / 6T, PA11 / 10T, PA11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T or PA11 / BACT / 10T, where T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine and BAC corresponds to bis(aminomethyl)cyclohexane.

[0050]

[0051] Advantageously, said thermoplastic polymer is a semi-crystalline polymer.

[0051]

[0052] Advantageously, said semi-crystalline polymer exhibits a glass transition temperature such as Tg≧80°C, in particular Tg≧100°C, in particular ≧120°C, in particular ≧140°C, and Mp 150°C.

[0052]

[0053] In the latter case, said at least semi-crystalline thermoplastic polymer is selected from poly(aryl ether ketone)s (PAEK), in particular poly(ether ether ketone)s (PEEK); poly(aryl ether ketone ketone)s (PAEKK), in particular poly(ether ketone ketone)s (PEKK); aromatic polyetherimides (PEI); polyarylsulfones, in particular polyphenylene sulfones (PPSU); polyarylsulfides, in particular polyphenylene sulfide (PPS); polyamides (PA), in particular semi-aromatic polyamides optionally modified with urea units (polyphthalamide); polyacrylates, in particular polymethyl methacrylate (PMMA); polyolefins other than polypropylene; polylactic acid (PLA); polyvinyl alcohol (PVA); polyvinyl chloride (PVC) and acrylonitrile-butadiene-styrene (ABS) polymers; and blends thereof, in particular blends of PEKK and PEI, preferably in an amount of 90-10% by weight to 60-40% by weight, in particular 90-10% by weight to 70-30% by weight.

[0053]

[0054] More advantageously, in the latter case, said at least thermoplastic polymer is chosen from polyamides, aliphatic polyamides, cycloaliphatic polyamides and semi-aromatic polyamides (polyphthalamides), PEKK, PEI and blends of PEKK and PEI.

[0054] Impregnated pultruded fiber material

[0055] In impregnated materials, also called "ready-to-use" materials, the impregnating thermoplastic polymer or blend of thermoplastic polymers is distributed uniformly and homogeneously around the fibers. In this type of material, in order to minimize porosity, the impregnating thermoplastic polymer must be distributed as homogeneously as possible in the fibers, i.e., the voids between the fibers are minimized. In particular, the presence of porosity in this type of material can act as stress concentration points, for example when placed under mechanical tensile stress, forming the initiation points of failure of the impregnated fiber material and mechanically weakening it. Thus, the homogeneous distribution of the polymer or blend of polymers improves the mechanical strength and homogeneity of the composite materials formed from these impregnated fiber materials.

[0055]

[0056] Advantageously, the fibre content in said pultruded impregnated fibrous material is between 45 and 70% by volume, preferably between 50 and 70% by volume, preferably between 50 and 60% by volume and in particular between 54 and 60% by volume, relative to the volume of the pultruded impregnated fibrous material.

[0056]

[0057] In general the measurement of the fiber content can be carried out by image analysis (especially using a microscope, a camera or a digital camera) of the cross-section of the cylindrical element and is calculated by dividing the surface area of ​​the fibers by the surface area of ​​the cylindrical element (impregnated surface area plus the porous surface area). To obtain good quality images, it is preferable to coat the transversely cut cylindrical elements with a standard polishing resin and polish them with a standard protocol that allows the observation of the sample under a microscope at a magnification of at least 6 times. The image size to be analyzed is 10-12 times the diameter of the fiber. Between 5 and 40 images are taken at different locations (sections). The average of all images is taken and recalculated per volume.

[0057]

[0058] For the measurement of the fiber content of a portion of the additional fiber reinforcement, if this is a fiber material based on continuous fibers impregnated with a thermoplastic matrix, the same measurement is carried out on a cross section perpendicular to the fiber direction of the additional fiber reinforcement.

[0058]

[0059] When the fibers are carbon fibers, the measurement of the carbon fiber content may be determined according to ISO 14127:2008.

[0059]

[0060] If the fibres are glass fibres, the measurement of fibre content is determined in accordance with ISO 1172:1999.

[0060]

[0061] Advantageously, the porosity of said impregnated fibrous material is less than 10%, in particular less than 5%, in particular less than 2%.

[0061]

[0062] It should be noted that zero porosity is difficult to achieve, so advantageously the porosity is greater than 0%, but less than the amounts stated above.

[0062]

[0063] The porosity corresponds to the closed porosity and β can be determined as the relative deviation between the theoretical and experimental density of the impregnated fibrous material by electron microscopy or as described in the examples section of EP 3 418 323.

[0063]

[0064] The composite material is leak-tight, inert, and resistant to the internal pressure of pressurized fluids.

[0064]

[0065] Preferably, the tank according to the invention comprises, as fibres, a fibre material selected from glass fibres, carbon fibres, basalt fibres, basalt-based fibres and, as thermoplastic matrix, a polymer selected from polyamide, aliphatic polyamide, cycloaliphatic polyamide, semi-aromatic polyamide (polyphthalamide), PEKK, PEI and blends of PEKK and PEI.

[0065]

[0066] In this way, the impregnated fibrous material is produced into a cylindrical shape by pultrusion.

[0066]

[0067] According to one embodiment, the inner diameter of the cylindrical element may be between 50 mm and 150 mm, this diameter size being particularly targeted at tanks for battery packs of automobiles, trailer chassis, etc.

[0067]

[0068] According to another embodiment, the inner diameter of the cylindrical element may be greater than 150 mm, this diameter size being particularly targeted for hydrogen transport trailer tanks.

[0068]

[0069] The length of the cylindrical element can be between 25 cm and 10 m, preferably between 50 cm and 3 m. A person skilled in the art will know how to adapt the dimensions of the cylindrical element according to the intended purpose of the tank.

[0069]

[0070] According to another embodiment, the ratio of the wall thickness of the tank to the inside diameter may be between 0.05 and 0.20, preferably between 0.08 and 0.12.

[0070] cap

[0071] The tank according to the invention comprises two caps at its ends, which are generally made of metal, preferably an aluminium alloy.

[0071]

[0072] The first cap is disposed on one end of the at least one cylindrical element and closes it, thus constituting the bottom of the tank.

[0072]

[0073] A second cap is disposed at the other end of the at least one cylindrical element and is fitted with an orifice intended to allow fluid to enter or exit, which may be a valve.

[0073]

[0074] According to one embodiment of the tank according to the invention, the first cap, which is arranged at one end of the at least one cylindrical element and closes it, may also be fitted with an orifice intended to allow the entry and exit of a fluid.

[0074]

[0075] The cap may have a hemispherical dome shape or a cone shape.

[0075]

[0076] To ensure leak tightness of the tank, an elastomeric seal can be disposed between the cap and the cylindrical element.

[0076] Additional fiber reinforcement

[0077] The tank according to the invention may also comprise at least one additional fibre reinforcement, partially or completely, in particular completely, surrounding the cylindrical element and optionally the cap.

[0077]

[0078] Within the meaning of the present invention, the term "fibrous reinforcement" is understood to mean a material containing fibers that gives greater mechanical strength to the final part.

[0078]

[0079] The additional fibrous reinforcement is selected from fibrous materials based on dry continuous fibres, continuous fibres impregnated with a thermoplastic matrix, and mixtures thereof.

[0079]

[0080] When the additional fibrous reinforcement is a dry fiber, the latter may be selected from those defined above.

[0080]

[0081] When the additional fibrous reinforcement is a fibrous material based on continuous fibres impregnated with a thermoplastic matrix, it may be the same as or different from the fibrous material constituting the cylindrical element.

[0081]

[0082] If the additional fiber reinforcement is a fiber material based on continuous fibers impregnated with a thermoplastic matrix, the total fiber content in the tank is between 40% and 70% by volume relative to the volume of the matrix and the volume of the fibers contained in the tank, taking into account the matrix of the pultruded thermoplastic-impregnated fiber material and the matrix of the additional fiber reinforcement, in other words the total fiber content of the tank is between 40% and 70% by volume relative to the volume of the matrix and the fibers contained in the tank.

[0082]

[0083] According to one embodiment, the additional fiber reinforcement is selected from a braid of dry fibers, a braid of fiber tapes impregnated with a thermoplastic resin, and mixtures thereof.

[0083]

[0084] Thus, according to a first embodiment, the fibres contained in the fibrous material may be braids of dry fibres and the additional fibrous reinforcement may also be braids of dry fibres.

[0084]

[0085] According to a second embodiment, the fibers contained in the fibrous material may be a roving of continuous fibers and the additional fibrous reinforcement may be a braid of dry fibers.

[0085]

[0086] According to a third embodiment, the fibers contained in the fibrous material may be a braid of fibers and the additional fibrous reinforcement may be a roving of dry continuous fibers.

[0086]

[0087] According to a fourth embodiment, the fibers contained in the fibrous material may be a braid of fibers and the additional fibrous reinforcement may be a roving of impregnated continuous fibers.

[0087]

[0088] According to a fifth embodiment, the fibres contained in the fibre material may be continuous fibre rovings, or continuous fibre rovings impregnated with additional fibre reinforcement.

[0088]

[0089] The thermoplastic matrix of the additional fiber reinforcement may be the same as or different from the thermoplastic matrix of the cylindrical element. Preferably, the thermoplastic matrix of the cylindrical element is fully or partially miscible with the thermoplastic matrix of the additional fiber reinforcement. This full or partial miscibility makes it possible to increase the adhesion between the wall of the cylindrical element and the layer of additional fiber reinforcement.

[0089]

[0090] According to a particular embodiment of the invention, the tank may comprise a cylindrical element whose thermoplastic matrix is ​​made of PVC and a fibrous reinforcement whose polymer matrix is ​​made of acrylic.

[0090]

[0091] According to another particular embodiment of the invention, the tank may comprise a cylindrical element whose thermoplastic matrix is ​​made of ABS and a fibrous reinforcement whose polymer matrix is ​​made of acrylic.

[0091]

[0092] According to another embodiment of the invention, the tank may comprise a cylindrical element whose thermoplastic matrix is ​​made of polyamide and a fibrous reinforcement whose polymer matrix is ​​made of polyphthalamide.

[0092]

[0093] Preferably, the thermoplastic matrix of the additional fiber reinforcement exhibits a melting point above 150°C.

[0093]

[0094] Preferably, the thermoplastic matrix of the additional fiber reinforcement exhibits a glass transition temperature above 80°C, preferably above 100°C, more particularly above 120°C.

[0094]

[0095] More particularly, the thermoplastic matrix of the additional fiber reinforcement exhibits a melting point greater than 150°C and a glass transition temperature greater than 80°C, preferably greater than 100°C, more particularly greater than 120°C.

[0095]

[0096] The thickness of the layer of fiber reinforcement may be between 0.5 mm and 10 mm, preferably between 0.5 mm and 5 mm.

[0096]

[0097] The total content of fibres is between 40 and 70% by volume, preferably between 50 and 70% by volume, relative to the sum of the volume of the matrix and the volume of the fibres.

[0097]

[0098] Within the meaning of the present invention, the term "total fiber content" is understood to mean the sum of the fiber content contained in the tank, i.e. the cylindrical element and the additional fiber reinforcement.

[0098]

[0099] The additional fiber reinforcement comprises fibers positioned along an axis different from the longitudinal axis of the cylindrical element, preferably at an angle between + / -10° and + / -89° relative to the longitudinal axis of the cylindrical element, preferably at an angle from the axis of the cylindrical element between + / -25° and + / -89°, more preferably between + / -45° and + / -89°.

[0099]

[0100] In other words, the longitudinal axis of the cylindrical element constitutes the 0° axis and the direction of the fibres of the additional reinforcement constitutes the second axis. The angle between these two axes is as defined above. The + / - sign indicates whether the fibres of the additional fibre reinforcement are positioned to the right or to the left according to the axis of the cylindrical element.

[0100]

[0101] It has been observed that by depositing fiber reinforcement on different axes, the resistance of the tank walls to internal pressure can be increased.

[0101]

[0102] Preferably, some of the fibres contained in the material of the cylindrical element are located on the longitudinal axis of the cylindrical element, more particularly, all of the fibres contained in the material of the cylindrical element are located along the axis of the cylindrical element.

[0102]

[0103] According to one embodiment, the tank can include a second cylindrical element, also called a liner, made of one or more layers of thermoplastic resin and free of fibers, which can increase the tank's airtightness, increase its pressure resistance and enhance the chemical resistance of the final part.

[0103]

[0104] In other words, the tank according to the invention may comprise a liner, then a cylindrical element as defined above, and furthermore an additional fibre reinforcement as defined above.

[0104]

[0105] The length and diameter of the tank can be larger or smaller, depending on the liquid to be stored and the structure that will receive the tank.

[0105]

[0106] Preferably, the tank according to the invention comprises: one or more cylindrical elements, the fibers of which are positioned on the axis of the cylindrical elements; - one or more additional fiber reinforcements, the fibers of which are positioned on an axis different from the axis of the cylindrical element; Including, The cap is fixed to the end of the cylindrical element by crimping. According to this embodiment, the cap is not hemispherical.

[0106]

[0107] Within the meaning of the present invention, the term "crimped" is understood to mean that the additional fiber reinforcement is crushed or flattened onto the cap.

[0107]

[0108] Preferably, the additional fiber reinforcement is a layer partially or completely, preferably completely, surrounding the cylindrical element, said layer being made of a fibrous material impregnated with a thermoplastic resin and being pre-flattened onto the cap.

[0108]

[0109] According to a particularly preferred embodiment, the tank according to the invention comprises: one or more cylindrical elements, the fibers of which are positioned on the axis of the cylindrical elements; - an additional fiber reinforcement, the fibers of which are positioned between + / - 45° and + / - 89° to the axis of the cylindrical element; Includes.

[0109]

[0110] According to another embodiment, the tank according to the invention comprises: one or more cylindrical elements, the fibers contained in the fibrous material being braided; one or more additional fiber reinforcements, the fibers being braids of dry or impregnated fibers positioned along an axis different from the axis of the braid of the cylindrical element; Includes.

[0110]

[0111] According to one embodiment, the tank according to the invention may comprise several cylindrical elements connected to one another and presenting an internal diameter of less than 250 mm, preferably less than 150 mm. According to said embodiment, the tank comprises: a first cap arranged at one end of the at least one cylindrical element and closing it, and then a cylindrical element made of a pultruded fiber material impregnated with a thermoplastic matrix, and then - connecting parts allowing both the inlet and outlet of the fluid and the connection with the adjacent cylindrical elements, and then a cylindrical element made of a pultruded fiber material impregnated with a thermoplastic matrix; This sequence: the connecting parts of the cylindrical elements can be repeated several times if necessary, then a final cap placed at the other end of the at least one cylindrical element and fitted with an orifice intended to allow the entry and exit of liquid from the entire tank; Includes.

[0111]

[0112] The invention also relates to a method for the manufacture of a tank according to the invention, said method comprising the following successive steps: (a) pultrusion of a cylindrical element; (b) placement of caps on the ends of the cylindrical element obtained at the end of step (a); (c) Stage of deposition of additional fiber reinforcement.

[0112]

[0113] According to one embodiment, the deposition step of the additional fiber reinforcement can be carried out by wrapping a tape of the additional fiber reinforcement around the cylindrical element and its cap, said deposition being carried out under a certain mechanical stress in order to apply pressure to the cap and to the cylindrical element.

[0113]

[0114] According to another embodiment, the cap presents an outer diameter smaller than the inner diameter of the cylindrical element, so that the cap can be inserted into the cylindrical element, in which case the fibrous reinforcement only wraps around the cylindrical element, since the latter already surrounds the cap.

[0114]

[0115] Finally, the invention relates to the use of a tank according to the invention for the storage, transportation and / or distribution of fluids such as gases in compressed, liquid or cryogenically compressed form, in particular hydrogen, natural gas, LPG, LNG, compressed air, nitrogen or oxygen.

[0115] Description of the drawings

[0116] The process according to the invention can be illustrated by FIG.

[0116]

[0117] Figure 1 shows the pultrusion process. The element 1 is an extruded tube (cylindrical element) which can give the shape to the final pultruded element. The dry fibres 3 leave a reel supported by a creel 2 and enter an impregnation zone 4. This zone 4 contains a bath of liquid resin or a head for injecting the resin. A pultrusion die 5 guides the pultruded impregnated fibre, resulting in a pultruded layer 6. The pultruded impregnated fibre is subjected to heating generated by a heating element 7. A reel 8 supports an additional fibrous reinforcement which is wound around the pultruded tube according to an angle 9. The entire pultruded tube is pulled by a puller 10. The pultruded tube is then cut by a cutting tool 11.

[0117]

[0118] Figure 2 shows an alternative pultrusion process. The element 21 is an extruded tube, which allows it to be shaped into the final pultruded element. The fibers impregnated with resin 23 leave a reel supported by a creel 22 and enter a pultrusion die 24. The latter guides the impregnated fibers to shape them, resulting in a pultruded layer 25. The pultruded impregnated fibers are subjected to heat generated by a heating element 26. A reel 27 supports an additional fibrous reinforcement that is wound around the pultruded tube according to an angle 28. The entire pultruded tube is pulled by a puller 29. The pultruded tube is then cut by a cutting tool 30.

[0118] Working Example

[0119] Example 1

[0120] Composite tubes of circular cross section, exhibiting an outer diameter of 170 mm and a thickness of 2 mm, are produced by pultrusion at a speed of 0.5 m / min, by a melt impregnation process, using a tubular die connected to a single-screw extruder. The resin used for pultrusion is a low-viscosity polyamide 11 grade (reference Rilsan® FMNO), allowing good impregnation of the fibers. The Mp of this polyamide 11 resin exhibits 190 ° C (measured according to standard ISO 11357-3:2013), the temperature in the pultrusion die was 250 ° C. The fibers used were 50K carbon fibers, reference Sigrafil CT 50 4.8 / 280 T140, sold by SGL. The fiber content was 45% by volume (fiber content relative to the volume of the pultruded tube). The orientation of the fibers in the pultrusion die was exclusively along the axis of the tube.

[0119]

[0121] The tube was cut to a length of 1.5 m. Two caps, 20 mm in length, were placed on each of the two ends of the tube. Rubson® brand gas-tight seals were placed at the interface between the caps and the tube. These caps consisted of 80 mm diameter aluminum cylinders drilled with M25 threaded holes to allow connection with standard connectors used in hydrogen.

[0120]

[0122] Additional reinforcement consisting of Hyosung H2550 G10 carbon fibre that was not impregnated with resin (i.e. dry fibre reinforcement) was wrapped helically around the pultruded tube, over a thickness of 4 mm, to absorb the forces exerted on the cap by the pressure inside the tube. A fibre reinforcement consisting of dry fibre was then wrapped over a thickness of 4 mm at an angle of 85° from the axis of the tube. One end of the tube was closed with an M25 threaded plug and pressurised to burst at ambient temperature. The measured burst pressure was 1600 bar.

[0121]

[0123] Example 2

[0124] Composite tubes of circular cross section, exhibiting an outer diameter of 170 mm and a thickness of 2 mm, are produced by pultrusion at a speed of 0.5 m / min, by a melt impregnation process, using a tubular die connected to a single-screw extruder. The resin used for pultrusion is a low-viscosity polyamide 11 grade (reference Rilsan® FMNO), allowing good impregnation of the fibers. The Mp of this polyamide 11 resin exhibits 190 ° C (measured according to standard ISO 11357-3:2013), the temperature in the pultrusion die was 250 ° C. The fibers used were 50K carbon fibers, reference Sigrafil CT 50 4.8 / 280 T140, sold by SGL. The fiber content was 45% by volume (fiber content relative to the volume of the pultruded tube). The orientation of the fibers in the pultrusion die was exclusively along the axis of the tube.

[0122]

[0125] The tube was cut to a length of 1.5 m. Two caps, 20 mm in length, were placed on each of the two ends of the tube. Rubson® brand gas-tight seals were placed at the interface between the caps and the tube. These caps consisted of 80 mm diameter aluminum cylinders drilled with M25 threaded holes to allow connection with standard connectors used in hydrogen.

[0123]

[0126] An additional fiber reinforcement consisting of a 1 / 2 inch wide composite tape was wrapped around the pultruded tube in a spiral manner over a thickness of 4 mm in order to absorb the forces exerted on the cap by the pressure inside the tube. The composite tape was then wrapped perpendicular to the axis of the tube (taking into account the width of the tape and the diameter of the pultruded tube, the fiber angle was approximately 85°) over a thickness of 4 mm. The composite tape consisted of Hyosung H2525 G10 carbon fiber impregnated with a polyamide 11 type resin (reference Rilsan® FMNO) exhibiting a glass transition temperature of 50°C (measured by DSC according to standard ISO 11357-2:2013). The fiber content was 55% by volume (relative to the volume of the composite tape). The composite tape was used by a Coriolis® Solo brand laser-heated automated deposition process at a temperature of 270°C and a speed of 0.3 m / s.

[0124]

[0127] The tube was closed at one end with an M25 threaded plug and pressurized to burst at ambient temperature, the measured burst pressure being 1670 bar.

[0125]

[0128] Example 3

[0129] Composite tubes of circular cross section, exhibiting an outer diameter of 170 mm and a thickness of 2 mm, are produced by pultrusion at a speed of 0.5 m / min, by a melt impregnation process, using a tubular die connected to a single screw extruder. The resin used for pultrusion is a low-viscosity polyamide 11 grade (reference Rilsan® FMNO), allowing good impregnation of the fibers. This polyamide 11 resin exhibits an Mp of 190 ° C (measured according to the ISO 11357-3:2013 standard) and the temperature in the pultrusion die was 250 ° C. The fibers used were 50K carbon fibers, reference Sigrafil® CT 50 4.8 / 280 T140, sold by SGL. The fiber content was 45% by volume (fiber content relative to the volume of the pultruded tube). The orientation of the fibers in the pultrusion die was exclusively along the axis of the tube.

[0126]

[0130] The pultruded tube was cut into segments 1.5 m long. Each segment was cut into strips 40 mm long at the ends along the axis of the tube, and these ends were heated to 150 °C and formed to cover two caps 20 mm long placed on each of the two ends of the tube. These caps consisted of 80 mm diameter aluminium cylinders drilled with M25 threaded holes to allow connection with standard connectors used in hydrogen.

[0127]

[0131] An additional fiber reinforcement consisting of a 1 / 2 inch wide composite tape was wrapped around the tube perpendicular to the axis (taking into account the width of the tape and the diameter of the pultruded tube, the fiber angle was approximately 85°) over a thickness of 6 mm. This tape was also wrapped around the end of the tube molded onto the metal cap (at the same wrapping angle to the fiber) to perform the crimping of the cap. The composite tape consisted of Hyosung H2525 G10 carbon fiber impregnated with a resin of the type PA 11 / BACT / 10T, exhibiting a glass transition temperature of 140°C (measured by DSC according to standard ISO 11357-2:2013). The fiber content was 55% by volume (relative to the volume of the composite tape). The composite tape was used by a Coriolis® Solo brand laser-heated automated deposition process at a temperature of 330°C and a speed of 0.3 m / s.

[0128]

[0132] Two tubes of the same type were manufactured and connected using M25 threaded caps and connectors with a diameter of 30 mm, one of the tubes was closed at one of its ends with an M25 threaded plug. The tank thus formed had a volume of 60 L and was pressure tested at a temperature of 23 ° C. The measured burst pressure was 1750 bar.

Claims

1. - At least one cylindrical element made of a drawn fiber material impregnated with a thermoplastic matrix, - A first cap disposed at one end of the at least one cylindrical element to close it, - A second cap disposed at the other end of the at least one cylindrical element, to which an orifice intended to allow the passage of fluid is attached, - At least one additional fiber reinforcement that partially or completely surrounds the cylindrical element and optionally the cap comprising The fibers included in the additional fiber reinforcement are positioned along an axis different from the longitudinal axis of the cylindrical element, The total fiber content of the tank is between 40% and 70% by volume with respect to the volume of the matrix and the volume of the fibers contained in the tank, A tank for containing a pressurized fluid.

2. The tank according to claim 1, characterized in that the additional fiber reinforcement is selected from dry continuous fibers, fiber materials based on continuous fibers impregnated with a thermoplastic matrix, and mixtures thereof.

3. The tank according to claim 1, characterized in that the additional fiber reinforcement includes fibers positioned at an angle between + / −10° and + / −89° with respect to the axis of the cylindrical element.

4. The tank according to claim 1, characterized in that a part of the fibers contained in the material of the cylindrical element is positioned along the longitudinal axis of the cylindrical element.

5. The tank according to claim 1, characterized in that the additional fiber reinforcement is selected from blades of dry continuous fibers, blades of fiber tapes impregnated with a thermoplastic resin, and mixtures thereof.

6. The tank according to claim 1, characterized in that the fibers used in the manufacture of the drawn fiber material of the cylindrical element are blades of dry fibers.

7. The tank according to claim 2, characterized in that the additional fiber reinforcement is a layer that partially or completely surrounds the cylindrical element and is pre-flattened over the cap, and the layer is made of a fibrous material impregnated with a thermoplastic resin.

8. The tank according to claim 2, characterized in that the thermoplastic matrix of the cylindrical element is completely or partially miscible with the thermoplastic matrix of the additional fiber reinforcement.

9. The tank according to claim 2, characterized in that the thermoplastic matrix of the additional fiber reinforcement exhibits a melting point above 150°C and / or a glass transition temperature above 80°C.

10. The tank according to claim 1, characterized in that the thermoplastic matrix of the cylindrical element mainly comprises a thermoplastic polymer or a blend of thermoplastic polymers.

11. The tank according to claim 10, characterized in that the thermoplastic polymer is selected from poly(aryl ether ketone) (PAEK), in particular poly(ether ether ketone) (PEEK); poly(aryl ether ketone ketone) (PAEKK), in particular poly(ether ketone ketone) (PEKK); aromatic polyetherimide (PEI); polyaryl sulfone, in particular polyphenylene sulfone (PPSU); polyaryl sulfide, in particular polyphenylene sulfide (PPS); polyamide (PA), in particular semi-aromatic polyamide (polyphthalamide) optionally modified with urea units; PEBA, among which those with M.p. exceeding 150 °C; polyacrylate, in particular polymethyl methacrylate (PMMA); polyolefins excluding polypropylene; polylactic acid (PLA); polyvinyl alcohol (PVA); fluoropolymers, in particular polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); polyvinyl chloride (PVC), and acrylonitrile-butadiene-styrene (ABS) polymers, and blends thereof.

12. The tank according to claim 10, characterized in that the thermoplastic polymer is selected from polyamide, aliphatic polyamide, alicyclic polyamide and semi-aromatic polyamide (polyphthalamide), PEKK, PEI, and blends of PEKK and PEI.

13. The tank according to claim 10, characterized in that the thermoplastic polymer is selected from aliphatic polyamide, alicyclic polyamide and semi-aromatic polyamide (polyphthalamide).

14. The tank according to claim 10, characterized in that the thermoplastic polymer is selected from polyamide 6 (PA6), polyamide 11 (PA11), polyamide 12 (PA12), polyamide 66 (PA66), polyamide 46 (PA46), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 11 / 1010 (PA11 / 1010), and polyamide 12 / 1010 (PA12 / 1010), or blends thereof or copolyamides thereof.

15. The thermoplastic polymer is of the formula A / XT wherein - A is selected from units derived from amino acids, units derived from lactams, and units corresponding to the formula (Ca diamine)·(Cb diacid) (wherein a represents the number of carbon atoms of the diamine, b represents the number of carbon atoms of the diacid, a and b are each between 4 and 36, preferably between 9 and 18), the (Ca diamine) units are selected from linear or branched aliphatic diamines, cycloaliphatic diamines and alkyl aromatic diamines, and the (Cb diacid) units are selected from linear or branched aliphatic diacids, cycloaliphatic diacids and aromatic diacids; - XT represents a unit obtained from the polycondensation of Cx diamine (wherein x represents the number of carbon atoms of Cx diamine, x is between 6 and 36, preferably between 9 and 18) and terephthalic acid] The tank according to claim 10, characterized in that it is selected from semi-aromatic polyamides of the formula A / XT.

16. The thermoplastic polymer is a semi-aromatic polyamide of the formula A / 6T, A / 9T, A / 10T or A / 11T [wherein A is as defined above], in particular, polyamide PA6 / 6T, PA66 / 6T, PA6I / 6T, PA MPMDT / 6T, PA11 / 10T, PA11 / 6T / 10T, PA MXD / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, or PA11 / BACT / 10T [wherein T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BACT corresponds to bis(aminomethyl)cyclohexane]] selected from the tank according to claim 15.

17. The tank according to claim 1, wherein the fibrous material is selected from glass fibers, carbon fibers, basalt fibers, and basalt-based fibers.

18. The tank according to claim 1, comprising a plurality of cylindrical elements connected to each other and having an inner diameter of less than 250 mm, preferably less than 150 mm.

19. The tank according to claim 1, comprising a second cylindrical element composed of one or more layers of a thermoplastic resin and containing no fibers, disposed inside the cylindrical element.

20. The tank according to claim 1, characterized in that the tank includes a liner.

21. A method for manufacturing the tank according to claim 1, comprising: (a) a step of drawing a cylindrical element; (b) a step of disposing a cap at the end of the cylindrical element obtained at the end of step (a); (c) a step of depositing an additional fiber reinforcement; and characterized by including these consecutive steps.

22. The method according to claim 21, wherein the step of depositing an additional fiber reinforcement is carried out by winding a tape of the additional fiber reinforcement around the cylindrical element and its cap.

23. The method according to claim 22, characterized in that the deposition is carried out under a constant mechanical stress to apply pressure to the cap and the cylindrical element.

24. Use of the tank according to claim 1 for the storage, transportation and / or distribution of fluids such as gases, particularly hydrogen, natural gas, LPG, LNG, compressed air, nitrogen or oxygen, in a compressed form, a liquid form or a cryogenic compressed form.

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