Method for manufacturing a pressurized gas tank made of composite material

Abstract

The invention relates to a method for manufacturing a composite material pressurized gas reservoir (2) comprising the following steps: - Obtaining a plastic casing (20) comprising a tubular conduit passing through an internal volume of the casing, - Obtaining a tubular structure comprising a set of dry fibers (13) including a central portion and two end portions, and a means for retaining the dry fibers of the central portion, - Inserting the tubular structure into the tubular conduit, - Deploying the dry fibers of the two end portions onto the plastic casing and impregnating these fibers with a resin, - Forming an external reinforcing casing (21) around the plastic casing, - Curing the resin, - Obtaining a composite material pressurized gas reservoir. Figure 10

Description

Title of the invention: Method for manufacturing a pressurized gas tank made of composite material technical field

[0001] The invention relates to a method for manufacturing a pressurized gas tank made of composite material which can be used in particular as a tank for compressed natural gas, a tank for compressed hydrogen gas, a tank for liquefied petroleum gas.

[0002] The invention can be used in the field of hydrogen vehicles. By "vehicle" is meant any motor vehicle such as a car, motorcycle, truck, bus, train, machine, in particular construction equipment. State of the art

[0003] Composite pressurized gas tanks used in hydrogen vehicles must be sufficiently resistant to the internal pressure exerted by the compressed gas, but also lightweight (compared to metal pressurized gas tanks) to facilitate their mobility and reduce the fuel consumption of hydrogen vehicles. To best meet these requirements, composite pressurized gas tanks comprise a plastic casing (also called a "liner") delimiting an internal volume for storing compressed gas and an external reinforcing casing comprising resin-impregnated fibers surrounding the plastic casing.

[0004] Thus, document WO2021255041 presents a technical solution in which the mechanical resistance of a composite pressurized gas tank is reinforced by reinforcing elements passing through the plastic casing. More specifically, the reinforcing elements comprise a set of resin-impregnated fibers and, due to their positioning, strengthen the pressurized gas tank by preventing it from deforming under the action of the internal pressure of the compressed gas.

[0005] However, this technical solution has drawbacks, including the fact that it is complex to implement and does not offer results of sufficient quality.

[0006] The invention aims in particular to overcome the drawbacks of the prior art.

[0007] More specifically, an objective of the invention, in at least one of its embodiments, is to provide a method for manufacturing a pressurized gas tank having improved resistance and easy implementation. Summary of the invention

[0008] To this end, the invention relates to a method for manufacturing a pressurized gas tank made of composite material comprising the following steps:

[0009] - Obtaining a plastic envelope delimiting an internal volume intended to house a gas under pressure, the plastic casing comprises an external surface having a posterior external face and an anterior external face opposite the posterior external face, and a tubular conduit passing through the internal volume and opening onto the posterior and anterior external faces,

[0010] - Obtaining a tubular structure comprising a set of dry fibers, said dry fiber assembly having a central part and two end parts positioned on either side of the central part, said tubular structure further comprising a means for retaining the dry fibers of the central part,

[0011] - Insertion of said tubular structure into the tubular conduit,

[0012] - Deployment of the dry fibers of the two end parts on the external surface,

[0013] - Impregnation of the dry fibers of the two end parts with a first resin deployed in the previous step,

[0014] - Formation of an external reinforcement layer of the outer shell made of plastic by winding fibers impregnated with a second resin around the plastic casing,

[0015] - Hardening of the first and second resins,

[0016] - Obtaining a pressurized gas reservoir made of composite material.

[0017] The general principle of the invention is based on the fact that the tubular structure It includes a means of holding the dry fibers in the central section. This configuration provides a sufficiently rigid central section with a consistent size, allowing for easy positioning of the tubular structure within the tubular conduit, which, by definition, has a predefined size. Furthermore, since the dry fibers in the two end sections lack a holding mechanism during their initial resin impregnation, they are easier to handle and impregnate, thus ensuring better impregnation homogeneity.

[0018] Thus, the invention is based on a completely new and inventive approach allowing the dry fibers of the two end parts of the tubular structure to be easily manipulated to be easily applied to the external surface of the plastic casing and impregnated by a first resin in a homogeneous manner.

[0019] The term "tubular conduit traversing the internal volume of the plastic envelope" means a passage formed in the plastic envelope and delimited by the plastic envelope going from one side to an opposite side of the plastic envelope, that is to say from the posterior external face to the anterior external face.

[0020] The term "tubular element", whether referring to the tubular conduit or the tubular structure, means an element having an elongated shape in a longitudinal direction and a closed shape in a cross-section to the longitudinal direction, for example a circular or rectangular shape.

[0021] The term "external surface of the plastic casing" means the surface of the plastic casing that is not in contact with the pressurized gas contained in the plastic casing and that does not form the tubular conduit.

[0022] The term "holding means" refers to a means that allows the fibers to remain close to one another without separating. This can be achieved by maintaining a distance of less than half a fiber cross-section between any two fibers in the dry fiber assembly. Thus, through the use of a holding means, the dry fiber assembly has a compact structure.

[0023] According to one embodiment of the invention, the tubular conduits each comprise a central zone and two end zones, such that the end zones connect the central zone to the posterior and anterior external faces of the outer surface of the plastic sheath. Preferably, each end zone has a cup-shaped depression. This configuration allows for better integration of the dry fibers of the two end portions with the plastic sheath.

[0024] The expression "Deployment of the dry fibers of the two end portions on the external surface" means that the dry fibers of the two end portions are affixed to the external surface of the plastic casing, in contact with the external surface of the plastic casing. Preferably, the deployment is circumferential such that the dry fibers of the two end portions of a tubular structure are distributed substantially evenly around the periphery of the tubular conduit in which the tubular structure is inserted. The "periphery of a tubular conduit" is defined as a region of the plastic casing covering an end area of ​​a tubular conduit and, as required, a peripheral area extending over a portion of the external face contiguous to said end area.

[0025] The expression "first resin impregnation of dry fibers" means that all dry fibers are coated with resin at least partially or totally. When the fibers are partially coated with resin, they are coated to more than 70%, that is, more than 70% of the total surface area of ​​the fibers in the fiber set is covered by resin. Thus, partial or total impregnation of all the fibers in a dry fiber set is preferable to impregnating only the outer fibers of a dry fiber set where only the fibers near the surface are impregnated. peripheral of the dry fiber set are exposed to the resin (partially or totally), typically 10% of the total number of fibers in the dry fiber set.

[0026] According to one embodiment of the invention, the set of dry fibers in the central part of the tubular structure has, in cross-section, a shape of a disc, a square, a rectangle or several lobes.

[0027] According to one embodiment of the invention, the plastic casing is made by injection, rotomolding or extrusion blow molding of a thermoplastic or thermosetting polymer material such as, for example, polyethylene, polyamide, polyphthalamide, polyurethane or silicone.

[0028] According to one embodiment of the invention, the composite material pressurized gas reservoir comprises twenty, thirty, thirty-six, forty-five, fifty-five, sixty-five, seventy-five, eighty-five, ninety-five or one hundred tubular structures.

[0029] According to one embodiment of the invention, the dry fibers of the two end portions have a beveled shape at the end, allowing them to maximize their contact with the plastic casing. This configuration increases the mechanical resistance of the composite gas pressure tank to the internal pressure of the compressed gas.

[0030] According to one embodiment of the invention, the dry fibers of the two end parts are flexible so as to be able to conform to the external surface of the plastic casing.

[0031] According to one embodiment of the invention, the tubular conduits are distributed equidistant from each other within the plastic casing. This configuration thus provides improved mechanical resistance of the composite pressurized gas tank throughout its entire volume.

[0032] According to one embodiment of the invention, the tubular conduits number twenty, thirty, thirty-six, forty-five, fifty-five, sixty-five, seventy-five, eighty-five, ninety-five, or one hundred in a single composite pressurized gas tank. This configuration thus provides improved mechanical resistance of the composite pressurized gas tank throughout its entire volume.

[0033] According to one embodiment of the invention, the central zone of the tubular conduits and the central part of the tubular structures are cylindrical. This configuration thus facilitates the insertion of the tubular structures into the tubular conduits.

[0034] According to one embodiment of the invention, the plastic casing forms a square or rectangular parallelepiped. Thus, this configuration allows for to facilitate the insertion of composite pressurized gas tanks into vehicles.

[0035] According to one embodiment of the invention, the outer reinforcing layer is in direct contact with the plastic outer layer. This configuration reduces the risk of deformation and cracking of the plastic outer layer.

[0036] According to one embodiment of the invention, the retaining means is a temporary and / or permanent retaining means. The expression "temporary retaining means" means that the retaining means has a time-limited action. The expression "permanent retaining means" means that the retaining means has an unlimited time-limited action. A temporary retaining means is characterized by the fact that it is removed after being held in place for a predetermined period. A permanent retaining means is characterized by the fact that it is not removed after a predetermined period; it remains in place. Thus, this characteristic allows for the implementation of several retaining means having different characteristics, which may, in particular, be complementary. The fact that the retaining means can be temporary allows it to be removed if necessary.Thus, this temporary support method allows the central part of the tubular structure to be stiffened during its insertion into the tubular conduit and can be removed after insertion to prevent it from unnecessarily adding weight to the tank.

[0037] According to one embodiment of the invention, in the case where the tubular structure includes a temporary holding means, the latter holds together the dry fibers of the central part and those of one of the two end parts, in particular those which first enter the tubular conduit to emerge on the other side of the plastic envelope.

[0038] According to one embodiment of the invention, the retaining means is a sheath, a pipe, wire, elastic, resin, a metal weld or adhesive tape.

[0039] According to one embodiment of the invention, the manufacturing process according to the invention comprises, after the step of inserting said tubular structure into the tubular conduit and before the step of deploying the dry fibers of the two end portions on the external surface, and in the case where said tubular structure includes a temporary retaining means, a step of removing the temporary retaining means. Thus, the ability to remove the temporary retaining means after the insertion of the tubular structure into the tubular conduit makes it possible to reduce the mass of the composite pressurized gas tank.

[0040] According to one embodiment of the invention, the manufacturing process according to the invention comprises, before the step of insertion into the tubular conduit of said The tubular structure includes, where applicable, a means of permanent support, a step of impregnating the dry fibers of the central part with a third resin, followed by a step of hardening the third resin. Thus, the resin impregnation of the central part allows the dry fibers of the entire assembly to be held together in such a way that they form an inseparable and permanent bundle.

[0041] According to one embodiment of the invention, the step of impregnating the dry fibers of the central part with a third resin is carried out before or after the insertion of the tubular structure into the tubular conduit.

[0042] According to one embodiment of the invention, the impregnation of the central part of the tubular structure is carried out by infusing resin (under vacuum or pressure) into a resin channel inside the tubular structure. The resin channel is formed in the center of the tubular structure and / or at its periphery, so as to impregnate the central part of the tubular structure over its entire volume (i.e., at least 70% of the total surface area of ​​the fibers in the central part of the fiber assembly is covered by resin) and / or on its surface. This configuration allows for better resin impregnation over the entire central part.

[0043] According to one embodiment of the invention, the manufacturing process according to the invention includes, before the step of deploying the dry fibers of the two end parts on the external surface, a step of applying to the external surface a means of reinforcing the posterior and anterior external faces on opposite peripheries of the tubular conduit.

[0044] The expression "Applying a reinforcing means to the external surface of the plastic casing" means that the reinforcing means is in contact with the external surface of the plastic casing.

[0045] The expression "opposite peripheries of a tubular conduit" means that the two peripheries are opposite to each other with respect to the longitudinal direction of a tubular conduit.

[0046] The positioning of the reinforcement means makes it possible to strengthen the composite pressurized gas tank. Indeed, this reinforcement means makes it possible to reduce the shear stress applied to the pressurized gas tank.

[0047] According to one embodiment of the invention, the reinforcement means comprises two joined or disjoined parts: one positioned in contact with the perimeter of the tubular conduit of the posterior external face of the plastic envelope and the other positioned in contact with the perimeter of the tubular conduit of the anterior external face of the plastic envelope.

[0048] According to one embodiment of the invention, the reinforcement means is in contact with at least one tubular structure.

[0049] According to one embodiment of the invention, the reinforcement means comprises fibers impregnated by a fourth resin.

[0050] According to one embodiment of the invention, the fibers of the tubular structure, the reinforcing means, and the outer reinforcing sheath are glass, basalt, carbon, and / or aramid fibers. The fiber material(s) are not necessarily the same in the tubular structure, the reinforcing means, and the outer reinforcing sheath. However, it is advantageous for the fiber material(s) of the tubular structure, the reinforcing means, and the outer reinforcing sheath to be the same, as this results in greater homogeneity within the pressurized gas reservoir.

[0051] According to one embodiment of the invention, the hardening step of the first and second resins consists of successively hardening the first resin and then the second resin. This allows for separate control of the hardening quality of the first resin and the hardening quality of the second resin.

[0052] Alternatively, the step of curing the first and second resins consists of curing the first and second resins simultaneously. This minimizes the number of steps in the manufacturing process.

[0053] According to one embodiment of the invention, the dry fiber assembly consists of n dry fiber subsets where n is a natural integer greater than or equal to 2, and the steps of deploying and impregnating the dry fibers of the two end parts on the external surface consist of deploying the dry fibers of the two end parts of a first of the n dry fiber subsets on the external surface and impregnating them with the first resin, and then repeating this operation with the dry fibers of each of the remaining n-1 subsets.

[0054] The expression "the set of dry fibers consists of n subsets of dry fibers" means that it is possible to divide all the dry fibers in the set of dry fibers into n groups of dry fibers, the term "groups" being referred to here as subsets. Thus, when n equals 2, the dry fibers in the set of dry fibers are divided into two subsets of dry fibers, so that the set of dry fibers consists of a first subset of dry fibers and a second set of dry fibers. When n equals 3, the dry fibers in the set of dry fibers are divided into three subsets of dry fibers, so that the set of dry fibers consists of a first subset of dry fibers, a second subset of dry fibers, and a third set of dry fibers.In the case where n is equal to 4, the dry fibers of the dry fiber set are divided into four dry fiber subsets so that the dry fiber set consists of a first dry fiber subset, . of a second subset of dry fibers, a third subset of dry fibers and a fourth set of dry fibers.

[0055] Implementing a deployment and impregnation operation on the dry fibers of a subset of dry fibers makes it possible to obtain a layer of deployed-impregnated fibers, for example, a first layer of deployed-impregnated fibers for the first of the n subsets of dry fibers. Thus, the expression "repeat this operation with the dry fibers of each of the remaining n-1 subsets" means that after obtaining the first layer of deployed-impregnated fibers, a second layer of deployed-impregnated fibers is obtained (in the case where n is greater than or equal to 2), then—possibly—a third layer of deployed-impregnated fibers is obtained (in the case where n is greater than or equal to 3), and so on until all the dry fibers of the two end parts of the dry fiber set are deployed and impregnated in n successive layers.

[0056] Thus, by deploying and impregnating the dry fibers of the two end parts by successive layers, a more rigid tubular structure and a pressurized gas reservoir more resistant to the internal pressure of the compressed gas are obtained.

[0057] According to one embodiment of the invention, the step of successively hardening the first resin and then the second resin consists of hardening the first resin impregnated on the deployed-impregnated fibers of the two end parts of the first of the n dry fiber subsets, then repeating this operation with the deployed-impregnated fibers of each of the remaining n-1 subsets, and then hardening the second resin.

[0058] Implementing a hardening operation of the first resin impregnated on the deployed-impregnated fibers of a subset of deployed-impregnated fibers makes it possible to obtain a layer of deployed-impregnated-hardened fibers, for example, a first layer of deployed-impregnated-hardened fibers in the case of the first of the n subsets of deployed-impregnated fibers.Thus, the expression "repeat this operation with the spread-impregnated fibers of each of the remaining n-1 subsets" means that after obtaining the first layer of spread-impregnated-cured fibers, there follows the obtaining of a second layer of spread-impregnated-cured fibers (in the case where n is greater than or equal to 2), then - possibly - the obtaining of a third layer of spread-impregnated-cured fibers (in the case where n is greater than or equal to 3) and so on until all the dry fibers of the two end parts of the dry fiber set are spread, impregnated and cured in n successive layers.

[0059] According to an alternative embodiment of the invention, the step of simultaneously hardening the first resin and the second resin consists of hardening simultaneously the first resin impregnated onto the deployed fibers of the two end parts of the n subsets of dry fibers and the second resin.

[0060] According to one embodiment of the invention, the surface area ratio between the contact area of ​​the two end portions of a subset of dry fibers in contact with the outer surface of the plastic casing and the cross-section of the central portion of the tubular structure is at least 5. This feature ensures that the contact area between the two end portions and the outer surface of the plastic casing is sufficiently large to reduce the shear stress in the resin connecting the tubular structure and the plastic casing. Furthermore, this feature optimizes the volume of the tubular structures to limit their mass in the composite pressurized gas tank.

[0061] According to one embodiment of the invention, the cross-section of the central part of the tubular structure has a surface area between 300 mm² and 1000 mm², and the contact area of ​​the two end parts of a subset of dry fibers in contact with the external surface of the plastic casing is between 3000 mm² and 15000 mm² for a composite material pressurized gas tank containing a gas compressed to a pressure of 700 bar. This configuration provides improved mechanical strength of the composite material pressurized gas tank.

[0062] According to one embodiment of the invention, the contact surface of one of the two end portions of a subset of dry fibers is equal to the contact surface of the other of the two end portions. This configuration makes it possible to obtain the same mechanical strength of the composite pressurized gas tank regardless of which face of the composite pressurized gas tank is considered.

[0063] According to one embodiment of the invention, the first, second, third and fourth resins are thermoplastic resins or thermosetting resins.

[0064] According to one embodiment of the invention, the first, second, third and fourth resins are polymer resins (epoxy, polyester or polyurethane).

[0065] According to one embodiment of the invention, the first, second, third, and fourth resins are of the same or different types. This configuration allows the use of resins with different properties depending on the desired effect.

[0066] According to one embodiment of the invention, the hardening of the first resin is partial, that is to say, only a part of the first resin impregnated onto the dry fibers of the central part is totally hardened or that partial crosslinking (that is to say, hardening lasting half the time required for obtaining a total) and uniform hardening of the first resin impregnated onto the dry fibers of the central part is achieved.

[0067] According to one embodiment of the invention, the partial or total hardening of the first resin is carried out before or after the insertion of the tubular structure into the tubular conduit.

[0068] According to one embodiment of the invention, the hardening of a resin (the first, second, third and / or fourth resin) is carried out immediately after the positioning of the element impregnated by this resin (the first fiber subset, the second fiber subset, the third fiber subset, etc., the reinforcement means and / or the external reinforcement envelope).

[0069] According to one embodiment of the invention, the hardening of the first resin, the second resin, the third resin and the fourth resin is carried out after the formation of the outer reinforcing envelope.

[0070] According to one embodiment of the invention, the tubular structure, the reinforcing means, and the external reinforcing sheath are subjected to a treatment designed to harden their resins (the first, second, third, and fourth resins) simultaneously. This configuration allows for greater homogeneity within the "tubular structure / reinforcing means / external reinforcing sheath" assembly.

[0071] According to one embodiment of the invention, the hardening of the resin (the first, second, third and fourth resins) is achieved by polymerization by heat treatment or UV treatment.

[0072] According to one embodiment of the invention, a partial hardening of the first resin impregnated onto the dry fibers of the n dry fiber subassemblies is carried out after the dry fibers have been impregnated and before their deployment on the external surface of the plastic casing. This characteristic thus gives the impregnated subassemblies the desired viscosity, thereby allowing for better handling of the element in question.

[0073] According to one embodiment of the invention, the outer reinforcing sheath is positioned between the end portions of the first subset of impregnated fibers and those of the second subset of impregnated fibers, or between the end portions of the second subset and those of the third subset. This configuration allows the outer reinforcing sheath to remain in the desired position around the plastic casing and thus to obtain improved mechanical strength of the pressurized gas tank.

[0074] According to one embodiment of the invention, the first subset of dry fibers of the dry fiber set comprises a number of dry fibers between 30% and 40% of the total number of dry fibers of the dry fiber set. This configuration allows for a homogeneous distribution of dry fibers between the different subsets of dry fibers.

[0075] According to one embodiment of the invention, the deployed fibers of the two end portions of a subset of deployed fibers of a tubular structure are superimposed on those of an adjacent tubular structure. The expression "the deployed fibers of the two end portions of a subset of fibers of a tubular structure are superimposed on those of another tubular structure" means that the deployed fibers at the two end portions of two neighboring tubular structures extend sufficiently to overlap. Thus, for example, the deployed fibers of the two end portions of a first subset of fibers of a tubular structure are positioned between the deployed fibers of the two end portions of a second subset of fibers. This configuration provides improved mechanical strength within the pressurized gas reservoir.

[0076] According to one embodiment of the invention, in order to deploy the dry fibers of the two end portions of an assembly or sub-assembly of dry fibers on the external surface of the plastic casing, a tool (for example, a mechanical tool) or blown air is applied at the inlets of the tubular conduit (i.e., at the two opposite peripheries of the tubular conduit). The use of a tool or blown air allows for better circumferential deployment of the dry fibers so as to distribute them in a substantially even manner on the two opposite peripheries of the tubular conduit.

[0077] According to one embodiment of the invention, after the dry fibers of the two end portions of the dry fiber assembly have been deployed on the outer surface of the plastic casing, inserts are positioned in the space formed by the separation of the dry fibers from the dry fiber assembly. The positioning of these inserts thus allows pressure to be exerted on the two end portions and the reinforcement means, thereby achieving better support and bonding between the two end portions, the reinforcement means, and the plastic casing.

[0078] According to one embodiment of the invention, the inserts are metal inserts or inserts made from carbon fibers cut and bonded together. In this way, the inserts are made of a sufficiently strong material to enable them to fulfill their function of securing the tubular structures to the reinforcement means and the plastic casing.

[0079] According to one embodiment of the invention, the inserts are made of a material compatible with the first resin and / or the second resin. This configuration allows the first resin and / or the second resin to hold the inserts in place. contact of the impregnated fibers of the impregnated fiber assembly and / or of the external reinforcing sheath.

[0080] According to one embodiment of the invention, locking means are positioned on the inserts. Thus, this configuration makes it possible to hold in place the inserts on which they are positioned.

[0081] According to one embodiment of the invention, the locking means are discs of fibers impregnated with a resin. This configuration allows sufficient bonding between the locking means and the inserts.

[0082] According to one embodiment of the invention, the composite pressurized gas tank includes a tubular fitting equipped with a valve for filling and / or emptying the pressurized gas tank. The fact that the pressurized gas tank includes a tubular fitting equipped with a valve allows for the filling and emptying of the gas contained in the composite pressurized gas tank. Brief description of the figures

[0083] Other features and advantages of the invention will become more apparent upon reading the following description of a preferred embodiment, given by way of simple illustrative and non-limiting example, and the accompanying drawings, among which:

[0084] [Fig-1] presents a vertical cross-section of the plastic casing illustrating the step of obtaining by molding the plastic casing, according to the invention, on which the weld joints between the different areas of the pressurized gas tank made of composite material can be observed.

[0085] [Fig.2] presents a vertical cross-section of the plastic casing illustrating the step of forming the tubular conduits, according to the invention, obtained by cutting the weld joints.

[0086] [Fig.3a] presents a vertical cross-section of the plastic casing illustrating the step of inserting the tubular structures into the tubular conduits, according to the invention.

[0087] [Fig.3b] presents a vertical cross-section of the plastic casing illustrating The step of inserting a tubular structure with a means of temporary retention into a tubular conduit. In this figure, the fibers of the tubular structure are represented as a single block, making it impossible to distinguish them individually.

[0088] [Fig.3c] presents a vertical cross-section of the plastic casing illustrating The step of inserting a tubular structure with a means of permanent retention into a tubular conduit. In this figure, the means of permanent retention is resin impregnated around the periphery of the fibers in the central part of the assembly. of fibers. In this figure, the fibers of the tubular structure are represented in the form of a single block, not allowing them to be distinguished individually.

[0089] [Fig. 3d] shows a vertical cross-section of the plastic casing illustrating the insertion step of a tubular structure with a means for permanent retention within a tubular conduit. In this figure, the permanent retention means is resin impregnated throughout the volume of the fibers in the central part of the fiber assembly. In this figure, the fibers of the tubular structure are represented as a single block, making it impossible to distinguish them individually.

[0090] [Fig.4] shows a vertical cross-section of the plastic casing illustrating the step of applying a reinforcing means to the plastic casing.

[0091] [Fig. 5a] and [Fig. 5b] present a vertical cross-section of the plastic casing illustrating the step of opening the dry fibers of the two end parts of the dry fiber assembly using blown air ([Fig.5a]) or a tool ([Fig.5b]).

[0092] [Fig.6] presents a vertical cross-section of the plastic casing illustrating the step of impregnating the dry fibers of the two end parts of the fiber assembly after these dry fibers have been deployed on the reinforcing medium.

[0093] [Fig.7] presents a vertical cross-section of the plastic casing illustrating the step of impregnating the dry fibers of the two end parts of a first subset of dry fibers of the fiber set after these dry fibers have been deployed on the reinforcing means.

[0094] [Fig.8] presents a vertical cross-section of the plastic casing illustrating the step of impregnating the dry fibers of the two end parts of a second subset of dry fibers of the fiber set after these dry fibers have been deployed on the fibers of the two end parts of the first subset of fibers.

[0095] [Fig.9] presents a vertical cross-section of the plastic casing illustrating The step of inserting an insert, according to the invention, onto the impregnated fibers of the two end parts of the fiber assembly. In this figure, the dry fibers of the two end parts are deployed successively by deploying the fibers of the two end parts of a first of the n fiber sub-assemblies and then successively deploying the fibers of the two end parts of the other sub-assemblies, or all the dry fibers of the two end parts are deployed in a single step.

[0096] [Fig. 10] presents a vertical section of the pressurized gas tank made of composite material illustrating the step of forming the external reinforcing shell around the plastic shell, by winding fibers impregnated by a second resin.

[0097] [Fig. 11] presents a vertical section of the plastic envelope illustrating the step of impregnating the dry fibers of the central part with a resin by a resin infusion technique in one (or more) resin channel(s) inside the tubular structure.

[0098] [Fig. 12a] and [Fig. 12b] show the positioning of the resin channel(s) inside the tubular structure of the resin impregnation step of the central part of [Fig. 11]. The resin channel(s) is / are positioned at the center of the tubular structure ([Fig. 12a]) or at the periphery ([Fig. 12b]).

[0099] [Fig. 13] presents a method of maintaining the dry fibers of the central part of the dry fiber assembly between them.

[0100] [Fig. 14a] and [Fig. 14b] illustrate two possibilities of winding the outer reinforcing envelope around the plastic envelope.

[0101] [Fig. 15] illustrates the possible position of the fiber attachment point to start winding fibers impregnated with a second resin onto the plastic casing.

[0102] [Fig. 16] illustrates the possible positions of the tubular fitting equipped with a valve allowing the entry and exit of a gas from the pressurized gas tank.

[0103] [Fig. 17a] shows the reinforcement means for covering the plastic envelope and [Fig. 17b] shows a top view of the plastic envelope illustrating the positioning step of the reinforcement means.

[0104] [Fig. 18] presents a top view of a way of deploying the dry fibers of the two end parts of the dry fiber assembly.

[0105] [Fig. 19] presents a vertical section of the pressurized gas tank made of composite material where two tubular connection positions equipped with a valve can be observed, allowing the entry and exit of a gas from the pressurized gas tank.

[0106] [Fig.20] presents a vertical section of the pressurized gas tank made of composite material where two tubular structures can be observed and the impregnated fibers of the two end parts of the impregnated fiber assembly of one tubular structure are superimposed with those of the other tubular structure. Detailed description

[0107] The figures consist of a schematic representation of embodiments of the invention. In the figures, the size of certain elements may be exaggerated and not drawn to scale for illustrative purposes.

[0108] Figure 1 is a vertical cross-section of the plastic casing 20 illustrating the molding step of the plastic casing 20 according to the invention. The plastic casing 20, also called a "liner" in English, is designed to house a pressurized gas. and thus allows the formation of a circumscribed space and therefore the delimitation of an internal volume capable of containing a gas under pressure. The external surface 2000 of the plastic casing 20 is shown in [Fig. 1]. The plastic casing 20 can have a square or rectangular parallelepiped shape in which tubular conduits 200 pass through the internal volume of the plastic casing 20 and open onto the posterior external face 201 and the anterior external face 202 of the casing 20. The tubular conduits 200 can thus be distributed equidistant from each other within the plastic casing 20 so as to delimit different zones within the pressurized gas reservoir made of composite material 2.The tubular conduits comprise a central zone 2001 and two end zones 2003, positioned at each end of the central zone 2001, such that the end zones 2003 connect the central zone 2001 to the posterior 201 and anterior 202 external faces of the external surface 2000 of the plastic casing 20. The two end zones 2003 are flared and each has a bowl-shaped depression zone 2004. The central zone 2001 of the tubular conduits 200 is cylindrical. Figure 1 shows the weld joints 22 between the different zones of the composite pressurized gas tank. These weld joints 22, due to the shape of the mold, are formed during the molding of the plastic casing 20.

[0109] Figure 2 is a vertical cross-section of the plastic casing 20 illustrating the step of forming the tubular conduits 200, according to the invention, obtained by cutting the weld seams. The plastic casing 20, also called a "liner," is designed to house a pressurized gas and thus forms a circumscribed space capable of containing a pressurized gas. The external surface 2000 of the plastic casing 20 is shown in Figure 2. The plastic casing 20 may have a square or rectangular parallelepiped shape in which tubular conduits 200 pass through the plastic casing 20, opening onto a rear external face 201 and an anterior external face 202 of the casing 20 in order to form tubular conduits 200 within the casing 20.The tubular conduits 200 can thus be distributed in the plastic casing 20 at equidistant intervals from each other so as to delimit different zones in the composite pressurized gas tank 2. The tubular conduits 200 comprise a central zone 2001 and two end zones 2003, positioned at each end of the central zone 2001, such that the end zones 2003 connect the central zone 2001 to the posterior external faces 201 and anterior external faces 202 of the external surface 2000 of the plastic casing 20. The two end zones 2003 are flared and have . Each has a depression zone 2004 in the shape of a bowl. The central zone 2001 of the tubular conduits 200 is cylindrical.

[0110] Figure 3a shows a vertical cross-section of the plastic casing 20 illustrating the insertion step of the tubular structures 1 into the tubular conduits 200, according to the invention. In this figure, two tubular structures 1, which enhance the mechanical resistance to pressure variations of the composite gas pressure tank 2, can be seen. Each of these tubular structures 1 is positioned in a separate tubular conduit 200. It can be observed in Figure 3a that the tubular structures 1 have cross-sections substantially equal to the cross-sections of the tubular conduits 200, both at the central area 2001 of the tubular conduit 200 and at the central portion 10 of the tubular structure 1. More precisely, for the tubular structure 1 to be inserted into the tubular conduit 200, the cross-section of the tubular structure 1 is less than or equal to the cross-section of the tubular conduit 200.The tubular structures 1 fill the space formed by the tubular conduits 200. The tubular structures 1 comprise a set of dry fibers 13 including a central portion 10 and two end portions 11, 12. When the tubular structure 1 is positioned in a tubular conduit 200, the dry fibers of the dry fiber set 13 are substantially parallel to the elongation direction of the tubular conduit 200; that is, the angle between the dry fibers of the dry fiber set 13 and the elongation direction of the tubular conduit 200 is not greater than 5°. Preferably, the ends of the dry fibers of the two end portions 11, 12 have a beveled shape to maximize their contact with the plastic sheath 20. This beveled shape is defined so that the dry fibers can fill the depression area 2004 while maximizing their contact with the plastic sheath.Preferably, the dry fibers of the two end portions 11, 12 are flexible enough to adhere to the outer surface 2000 of the plastic casing 20. The tubular structures 1 are defined to connect two opposite faces (the rear outer face 201 and the front outer face 202) of the plastic casing 20. The tubular structures 1 include a retaining means 4 for the dry fibers of the central portion 10, enabling the dry fibers of the central portion 10 to be held within a defined space. The retaining means 4 is either temporary 41 or permanent 42. The retaining means 4 is a sheath, a tube, wire, an elastic band, resin, a metal weld, or adhesive tape. If the retaining means 4 is resin, the resin is cured before the tubular structure 1 is inserted into the tubular conduit 200.In the case where the retaining means 4 is temporary, it is removed after the tubular structure 1 has been introduced into the tubular conduit 200. No retaining means 4. are applied to the two end portions 11, 12. In [Fig. 3a], the plastic casing 20, also called a "liner" in English, is shown. This plastic casing 20 is designed to house a pressurized gas and thus forms a circumscribed space capable of containing a pressurized gas. The external surface 2000 of the plastic casing 20 is shown in [Fig. 3a]. The plastic casing 20 may have a square or rectangular parallelepiped shape in which tubular conduits 200 pass through the plastic casing 20, opening onto a posterior external face 201 and an anterior external face 202 of the casing 20 to form tubular conduits 200 within the casing 20.The tubular conduits 200 can be distributed equidistant from each other within the plastic casing 20 to delineate different zones within the composite pressurized gas reservoir. The tubular conduits 200 comprise a central zone 2001 and two end zones 2003, positioned at each end of the central zone 2001, such that the end zones 2003 connect the central zone 2001 to the posterior 201 and anterior 202 external faces of the external surface 2000 of the plastic casing 20. The two end zones 2003 are flared and each has a bowl-shaped depression zone 2004. The central zone 2001 of the tubular conduits 200 and the tubular structures 1 is cylindrical.

[0111] Figure 3b shows a vertical cross-section of the plastic casing 20 illustrating the insertion step of a tubular structure 1 into a tubular conduit 200. The tubular structure 1 has a temporary retaining means 4L. In the figure, on the left is shown the tubular structure 1 with the temporary retaining means 41 positioned along the entire length of the fibers of the fiber assembly 13. In the center of the figure is shown the insertion step into the tubular conduit 200 of the tubular structure 1 with its temporary retaining means 41 (positioned along the entire length of the fibers), allowing for easier manipulation of the fibers of the dry fiber assembly 13 for insertion into the tubular conduit 200. On the right is shown the removal step of the temporary retaining means 4L.

[0112] Figure 3c shows a vertical cross-section of the plastic casing 20 illustrating the step of inserting a tubular structure 1 into a tubular conduit 200, the tubular structure 1 having a permanent retaining means 42, which is resin. In the figure, on the left is shown the tubular structure 1 with the permanent retaining means 42, i.e., resin impregnated along the entire length of the fibers of the central part of the dry fiber assembly 13 and at the periphery of the central part of the fibers of the dry fiber assembly 13. In the center of the figure is shown the partial hardening stage of the resin (i.e., a hardening that has lasted half the time required to obtain full hardening). total) impregnating the dry fiber assembly 13. To the right of the figure is shown the insertion step into the tubular conduit 200 of the tubular structure 1 impregnated by a resin on the periphery and over the entire length of the fibers of the central part of the dry fiber assembly 13, allowing it to facilitate the handling of the fibers of the fiber assembly to insert them into the tubular conduit 200.

[0113] Figure 3d shows a vertical cross-section of the plastic casing 20 illustrating the step of inserting a tubular structure 1 into a tubular conduit 200, the tubular structure 1 having a permanent retaining means 42 being resin. In the figure, on the left, the tubular structure 1 is shown with resin impregnated along the entire length of the fibers in the central part of the dry fiber assembly 13 and throughout the entire volume of the fibers in the central part of the dry fiber assembly 13 (i.e., at least 70% of the total surface area of ​​the fibers in the dry fiber assembly 13 is covered by resin). In the center of the figure is shown the partial curing step (i.e., curing lasting half the time required to achieve full curing) of the resin impregnating the fibers in the central part of the dry fiber assembly 13.On the right of the figure is shown the insertion step into the tubular conduit 200 of the tubular structure 1 impregnated by a resin over the entire volume of the fibers of the central part of the dry fiber assembly 13, allowing it to facilitate manipulation of the fibers of the fiber assembly to insert them into the tubular conduit 200.

[0114] Figure 4 shows a vertical cross-section of the plastic casing 20 illustrating the step of applying a reinforcing means 16 to the external surface 2000 of the plastic casing 20 so as to be in contact with the two opposite peripheries 2005, 2006 of at least one tubular conduit 200. Preferably, the reinforcing means 16 is a mat of fibers impregnated with a fourth resin. In this figure, two tubular structures 1 for reinforcing the mechanical resistance to pressure variations of the pressurized gas tank made of composite material 2 can be seen. Each of these tubular structures 1 is positioned in a separate tubular conduit 200.

[0115] Figure 5 shows a vertical cross-section of the plastic casing 20 illustrating the step of opening the dry fibers of the two end portions 11, 12 of the dry fiber assembly 13 using blown air ([Fig. 5a]) (the application points of which are indicated by arrows 27) or a tool 28 ([Fig. 5b]). For this purpose, the blown air or the tool 28 is applied to the two opposite peripheries 2005, 2006 of the tubular conduit 200. During this step of opening the dry fibers of the two end portions 11, 12, the gas contained in the composite material pressurized gas reservoir 2 exerts a pressure P on the tubular structure 1 compensating for the pressure exerted by the blown air or the tool 28 applying in undesired areas and thus allowing the tool not to deform the pressurized gas tank made of composite material 2 and not to alter the position of the fibers of the central part of the tubular structure 1 in the tubular conduit 200.

[0116] Figure 6 shows a vertical cross-section of the plastic casing illustrating the step of impregnating all the dry fibers of the two end portions 11, 12 of the dry fiber assembly 13 with a first resin after these dry fibers have been deployed on the reinforcing means 16. This Figure 6 reproduces the same description as that of Figure 4. Following the step of impregnating all the dry fibers of the two end portions 11, 12 of the dry fiber assembly 13, the first resin is cured.

[0117] Fig. 7 presents a vertical section of the plastic envelope 20 illustrating the step of impregnating the dry fibers of the two end parts 11, 12 of a first subset of dry fibers 131 of the fiber set with a first resin after these dry fibers have been deployed on the reinforcing means 16. Preferably, the reinforcing means 16 is a mat of fibers impregnated with a fourth resin. During this step, a first subset of dry fibers 131 is separated from the dry fibers of the dry fiber set 13 and is deployed on the reinforcing means 16. The dry fibers of the two end parts 11,12 of the first subset of dry fibers 131 are deployed on the external surface 2000 of the plastic envelope 20 so that these two end parts 11,12 cover the entire depression area 2004.These dry fibers from the two end portions 11, 12 are then unfolded and positioned on the outer surface 2000 of the plastic casing 20. This operation can be described as peeling a banana, with the banana peel unfolded so that it can be applied to the skin of the hand of the person holding the banana. The surface area ratio between the contact area of ​​the two end portions 11, 12 of the first subset of dry fibers 131 in contact with the outer surface 2000 of the plastic casing 20 and the cross-section of the central portion 10 of the tubular structure 1 is at least 5. Only the dry fibers forming a ring in contact with the dry fibers at the center of the dry fiber assembly 13 constitute the first subset of dry fibers 131.The first subset of dry fibers 131 of the dry fiber set 13 comprises between 30% and 40% of the total number of dry fibers in the dry fiber set 13. After deploying the first subset of dry fibers 131 on the reinforcing means 16, the first subset of dry fibers 131 is impregnated with a first resin, and then the first resin is cured. In this figure, two tubular structures 1 allow... Reinforcing the mechanical resistance to pressure variations of the composite material pressurized gas tank 2 can be observed. Each of these tubular structures 1 is positioned in a separate tubular conduit 200.

[0118] Fig. 8 presents a vertical section of the plastic envelope 20 illustrating the step of impregnating the dry fibers of the two end parts 11, 12 of a second subset of dry fibers 132 of the fiber set 13 with a first resin after these dry fibers have been deployed on the fibers of the two end parts 11, 12 of the first deployed-impregnated fiber subset. In this figure, the reinforcement means 16 is positioned on the external surface 2000 of the plastic envelope 20, the fibers of the two end parts of the first subset of impregnated fibers are positioned on the reinforcement means 16. During this step, the dry fibers of the two end parts of a second subset of dry fibers 132 are separated from the dry fibers of the set of dry fibers 13 and are deployed on the fibers of the two end parts of the first subset of impregnated fibers.This operation can be defined as peeling a banana, and the banana peel is unfolded so that it can be applied to the skin of the hand of the person holding the banana. The surface area ratio between the contact area of ​​the two end portions 11, 12 of the second subset of dry fibers 132 in contact with the two end portions 11, 12 of the first subset of fibers 131 and the cross-section of the central portion 10 of the tubular structure 1 is at least 5. The dry fibers of the second subset of dry fibers 132 are unfolded and then positioned on the impregnated fibers of the two end portions 11, 12 of the first subset of unfolded-impregnated-hardened fibers. For this purpose, only the dry fibers forming a ring in contact with the dry fibers of the first subset of dry fibers 131 constitute the second subset of dry fibers 132.The second subset of dry fibers 132 of the dry fiber set 13 comprises between 30% and 40% of the total number of fibers in the dry fiber set 13. After deploying the dry fibers from the two end portions 11, 12 of the second dry fiber subset 132 onto the fibers from the two end portions 11, 12 of the first deployed-impregnated-cured fiber subset, the fibers from the two end portions 11, 12 of the second dry fiber subset 132 are impregnated with the first resin, and then the first resin impregnating the fibers from the two end portions of the second deployed-impregnated fiber subset is cured. In this figure, two tubular structures 1 for increasing the mechanical resistance to pressure variations of the pressurized gas reservoir 2 can be seen. Each of these tubular structures 1 is positioned within a separate tubular conduit 200. HAS . following this step of hardening the first resin impregnating the fibers of the two end parts 11,12 of the second subset of dry fibers 132 of the fiber set 13, the other subsets of dry fibers (in the case where n is greater than 2) are deployed successively, impregnated successively by a first resin (after the deployment of each subset of fibers) and the first resin impregnating them is hardened (after the impregnation of each subset of fibers).

[0119] Figure 9 illustrates the positioning of the inserts 14, which are positioned after the fibers of the two end portions 11, 12 of the last deployed-impregnated-cured fiber subset have been positioned in the space formed by the separation of the dry fibers from the dry fiber assembly 13. The role of the insert 14 is to increase the mechanical strength of the composite pressurized gas tank 2. Preferably, the inserts 14 are metal inserts or inserts made from carbon fibers cut and bonded together. Advantageously, the inserts 14 are made of a material compatible with the resin with which the dry fiber subsets of the dry fiber assembly 13 are impregnated and / or with the resin with which the fibers of the outer reinforcing sheath are impregnated. In this Figure 9, the inserts 14 are positioned after the fibers of the two end portions 11, 12 of the last deployed-impregnated-cured fiber subset are positioned in the space formed by the separation of the dry fibers from the dry fiber assembly 13.9], either the reinforcing means 16 is positioned on the external surface 2000 of the plastic casing 20, the fibers of the two end parts of the first subset of deployed-impregnated-hardened fibers are positioned on the reinforcing means 16, the fibers of the two end parts of the second subset of deployed-impregnated-hardened fibers are positioned on the fibers of the two end parts of the first subset of deployed-impregnated-hardened fibers and the other subsets of deployed-impregnated-hardened fibers are positioned successively up to the nth subset of deployed-impregnated-hardened fibers, or the reinforcing means 16 is positioned on the external surface 2000 of the plastic casing 20 and all the fibers of the two end parts 11,12 are deployed-impregnated-hardened in one go.

[0120] Figure 10 shows a vertical cross-section of the composite pressurized gas tank 2 illustrating the step of forming the outer reinforcing casing 21 around the plastic casing 20 by winding fibers impregnated with a second resin. The outer reinforcing casing 21 is a polymer reinforced with continuous resin-impregnated fibers. The outer reinforcing casing 21 is therefore made of composite material. The outer reinforcing casing 21 is the body of the composite pressurized gas tank 2, that is, the resistant structure of the composite pressurized gas tank 2 which will give the composite pressurized gas tank its strength. 2. The capacity to withstand the pressures exerted by the gas contained in the composite pressurized gas tank 2. The outer reinforcing casing 21 is not generally required to ensure the seal of the composite pressurized gas tank 2, as the seal of the composite pressurized gas tank 2 is achieved by the plastic casing 20. After forming the outer reinforcing casing 21 around the plastic casing 20, the resins impregnating the reinforcing means, the fibers of the two end portions of the fiber subassemblies of the fiber assembly, and the outer reinforcing casing 21 can be cured. The curing of a resin can also be carried out immediately after the positioning of the element impregnated by that resin (which may be the reinforcing means, the fibers of the two end portions of the fiber subassemblies, or the outer reinforcing casing).The resins impregnating the reinforcing means, the fibers of the two end portions of the fiber subassemblies 131, 132, 133 of the fiber assembly, and the outer reinforcing sheath 21 are of the same or different materials. The resins are cured by applying a heat treatment or a UV treatment. The inserts 14 shown in [Fig. 10] increase the mechanical strength of the composite pressurized gas tank 2. Preferably, the inserts 14 are metal inserts or inserts made from cut and bonded carbon fibers. Advantageously, the inserts 14 are made of a material compatible with the resin with which the dry fiber subassemblies of the dry fiber assembly 13 are impregnated and / or with the resin with which the fibers of the outer reinforcing sheath 21 are impregnated.During the manufacture of the composite pressurized gas tank 2, a locking means is affixed to each insert 14 of the composite pressurized gas tank 2. The locking means hold the insert 14 in place. The locking means are preferably a disc of resin-impregnated fibers. The locking means are not shown in the figures.In this figure, either the reinforcement means is positioned on the external surface 2000 of the plastic envelope 20, the fibers of the two end parts of the first subset of expanded-impregnated-hardened fibers are positioned on the reinforcement means, the fibers of the two end parts of the second subset of expanded-impregnated-hardened fibers are positioned on the fibers of the two end parts of the first subset of expanded-impregnated-hardened fibers, the other subsets of expanded-impregnated-hardened fibers are positioned successively up to the nth subset of expanded-impregnated-hardened fibers, or the reinforcement means is positioned on the surface. external 2000 of the plastic envelope 20 and all the fibers of both end parts are deployed-impregnated-cured in one go.

[0121] Figure 11 shows a vertical cross-section of the plastic casing 20 illustrating the resin impregnation step of the dry fibers of the central part 10 by a resin infusion technique in one (or more) resin channel(s) 23 inside the tubular structure 1, allowing the tubular structure 1 to be impregnated throughout its entire volume. The channel is shown as a dashed line in Figure 11. The two arrows represent the two resin inlets into the channel 23.

[0122] Fig. 12a and 12b present a horizontal section of the plastic envelope 20 illustrating the resin impregnation step of the dry fibers of the central part 10 by a resin infusion technique in one (or more) resin channel(s) 23 inside the tubular structure 1 at the center of the tubular structure 1 (Fig. 12a) or at the periphery of the tubular structure 1 (Fig. 12b). According to this method, the impregnation of the fibers of the central part 10 is carried out by an infusion of resin (under vacuum or by pressure) into one (or more) resin channel(s) 23 inside the tubular structure 1. The resin channel 23 is formed in the center of the tubular structure 1 ([Fig. 12a]) and / or at the periphery of the tubular structure 1 ([Fig. 12b]), so as to be able to impregnate the tubular structure 1 over its entire volume and / or on its surface.

[0123] Figure 13 shows a method for holding the dry fibers of the set of dry fibers 13 together at the central part 10. According to this method, the dry fibers 26 are held together at their central part 10 by means of threads 24. In this figure, steps 1, 2, 3, 4, and 5 result in dry fibers 26 held together at the central part 10 by threads 24. In step 1, the spools of dry fibers 25 can be seen. In step 2, the dry fibers 26 and the threads 24 are positioned on a table. The yarns 24 are positioned perpendicular to the dry fibers 26. In step 3, the dry fibers 26 are cut to obtain the desired length of the dry fibers 26 constituting the tubular structure 1. In step 4, the dry fibers 26 are brought together to form the tubular structure 1. In step 5, the dry fibers 26 are grouped together to form the tubular structure 1.Only the fibers in the central part 10 are held in place by the threads 24. As illustrated by options A, B, and C, the threads 24 can encircle all the fibers 13 (option A), only every other fiber (option B), or two out of every four fibers (option C). Options A, B, and C can be combined for the same set of fibers 13.

[0124] Fig. 14a and 14b show two possibilities for winding the outer reinforcing envelope 21 around the plastic envelope 20.

[0125] Fig. 15 shows the possible position of the attachment point 18 of the fibers to start the winding of fibers impregnated by a second resin on the plastic sheath to form the external reinforcing sheath 21.

[0126] Figure 16 illustrates the possible positions 30, 31, 32 of the tubular fitting equipped with a valve allowing the inlet and outlet of a gas from the composite pressurized gas tank. The tubular fitting is not shown in Figure 16.

[0127] Figure 17a shows the reinforcement means 16 for covering the plastic casing 20. Figure 17b shows a top view of the plastic casing 20 illustrating the positioning step of the reinforcement means 16. The reinforcement means 16 includes openings 165 for the passage of tubular structures 1 so that they can fill the tubular conduits 200. A tubular structure 1 is inserted into each tubular conduit 200, and the two end portions 11, 12 of each tubular structure 1 are unfolded. An insert 14 is positioned at each gap formed by the separation of the fibers in each set of impregnated fibers.

[0128] Figure 18 shows a top view of a way of deploying the two end portions 11, 12. The dry fibers of the dry fiber subassemblies of the dry fiber assembly 13 are separated into several dry fiber groups so as to cover the outer surface of the plastic sheath discontinuously. Only in the area near the tubular conduit 200 are the dry fiber subassemblies partially overlapped.

[0129] Fig. 19 shows a vertical section of the composite material pressurized gas reservoir 2 where two positions 30, 31 of tubular fitting 17 equipped with a valve 15 can be observed allowing the entry and exit of a gas from the composite material pressurized gas reservoir 2.

[0130] Fig. 20 presents a vertical section of the pressurized gas reservoir made of composite material 2 where two tubular structures 1 can be observed and the two end parts 11, 12 of the impregnated fiber subassemblies of one tubular structure 1 are superimposed with those of the other tubular structure 1. List of references

[0131] 1: tubular structure 2: Pressurized gas tank made of composite material 4: means of maintenance 10: central part 11, 12: two end parts 13: collection of dry fibers 14: insert 15: valve 16: means of reinforcement 17: Tubular fitting 18: fixing point 20: plastic casing 21: External reinforcement layer 22: weld joints 23: resin channels 24: son 25: reel of dry fibers 26: dry fiber 27: arrows 28: tool 30, 31, 32: possible positions of the tubular fitting 41: means of temporary restraint 42: means of permanent maintenance 131, 132, 133: n subsets of dry fibers 131: first subset of dry fibers 132: second subset of dry fibers 133: third subset of dry fibers 165: Openings 200: tubular conduit 201: posterior external surface 202: anterior external face 2000: external surface 2001: central zone 2003: two zones at the extremities 2004: Depression zone 2005, 2006: opposite sides

Claims

Demands

1. A method for manufacturing a pressurized gas reservoir made of composite material (2), the method is characterized in that it comprises the following steps: - Obtaining a plastic casing (20) delimiting an internal volume intended to hold a pressurized gas, the plastic casing (20) comprising an external surface (2000) having a rear external face (201) and an anterior external face (202) opposite the rear external face (201), and a tubular conduit (200) passing through the internal volume and opening onto the rear external face (201) and the anterior external face (202), - Obtaining a tubular structure (1) comprising a set of dry fibers (13), said set of dry fibers (13) having a central part (10) and two end parts (11, 12) positioned on either side of the central part (10),said tubular structure (1) further comprising a means for retaining (4) the dry fibers of the central part (10), - Insertion of said tubular structure (1) into the tubular conduit (200), - Deployment of the dry fibers of the two end parts (11,12) on the external surface (2000), - Impregnation with a first resin of the dry fibers of the two end parts (11,12) deployed in the previous step, - Formation of an external reinforcing sheath (21) of the plastic sheath (20) by winding fibers impregnated with a second resin around the plastic sheath (20), - Hardening of the first and second resins, - Obtaining a pressurized gas reservoir made of composite material (2).

2. A manufacturing method according to the preceding claim, wherein the retaining means (4) is a temporary (41) and / or permanent (42) retaining means.

3. A manufacturing method according to the preceding claim, comprising, prior to the step of inserting said tubular structure (1) into the tubular conduit (200), and in the case where said tubular structure (1) comprises a permanent retaining means (42), a step impregnation by a third resin of the dry fibers of the central part (10) and a hardening step of the third resin.

4. A manufacturing method according to claim 2, comprising, after the step of inserting said tubular structure (1) into the tubular conduit (200) and before the step of deploying the dry fibers of the two end parts (11,12) on the external surface (2000), and in the case where said tubular structure (1) includes a temporary retaining means (41), a step of removing the temporary retaining means (41).

5. A manufacturing method according to any one of the preceding claims, comprising, before the step of deploying the dry fibers of the two end parts (11,12) on the external surface (2000), a step of applying to the external surface (2000) a means of reinforcing (16) the posterior (201) and anterior (202) external faces on opposite peripheries (2005, 2006) of the tubular conduit (200).

6. A manufacturing method according to the preceding claim, wherein the reinforcing means (16) comprises fibers impregnated with a fourth resin.

7. A manufacturing method according to any one of the preceding claims, wherein the step of hardening the first and second resins consists of successively hardening the first resin and then the second resin.

8. A manufacturing method according to any one of claims 1 to 6, wherein the step of curing the first and second resins consists of simultaneously curing the first resin and the second resin.

9. A manufacturing method according to any one of the preceding claims, wherein the dry fiber assembly (13) consists of n dry fiber sub-assemblies (131, 132, 133) where n is a natural number greater than or equal to 2, and the steps of deploying and impregnating the dry fibers of the two end parts (11,12) on the external surface (2000) consist of deploying the dry fibers of the two end parts (11,12) of a first of the n dry fiber sub-assemblies (131, 132, 133) on the external surface (2000) and impregnating them with the first resin, and then repeating this operation with the dry fibers of each of the remaining n-1 sub-assemblies.

10. A manufacturing method according to the preceding claim taken in combination with claim 7, wherein the successive curing step of the first resin and then of the second resin consists of curing the first resin impregnated on the spread-impregnated fibers of the two end parts (11,12) of the first of the n dry fiber subsets (131, 132, 133), then repeating this operation with the spread-impregnated fibers of each of the remaining n-1 subsets, and then curing the second resin.

11. A manufacturing method according to claim 9 taken in combination with claim 8, wherein the step of simultaneously curing the first resin and the second resin consists of simultaneously curing the first resin impregnated on the deployed fibers of the two end parts (11,12) of the n dry fiber subsets (131, 132, 133) and the second resin.

12. A manufacturing method according to any one of the preceding claims, wherein the composite material pressurized gas tank (2) includes a tubular fitting (17) equipped with a valve (15) for filling and / or emptying the pressurized gas tank.

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