Reservoir designed to contain a pressurized gas with an improved nozzle

Abstract

The invention relates to a tank (10) comprising a liner (12) having a neck (14), a reinforcing envelope (18) covering the liner (12), and a nozzle (20) formed in the neck (14) which comprises: an axial opening (22), a first annular projection (31) extending radially outwards from the axial opening (22), a second annular projection (32) extending radially outwards from the axial opening (22), arranged axially outwards from the first projection (31), and an external axial end (24) extending at least partly outside the tank (10). The reservoir (10) includes a sealed contact surface (SG) between the nozzle (20) and the neck (14) extending between the first projection (31) and the second projection (32), and a contact surface (SE) between the nozzle (20) and the reinforcing sleeve (18), which extends axially between the second projection (32) and the outer axial end (24).Figure for the abridged version: figure 6.

Description

Title of the invention: Reservoir for containing a pressurized gas with an improved nozzle

[0001] The invention relates to tanks for containing gases under pressure, particularly tanks installed in motor vehicles. More specifically, the invention relates to a tank for containing a gas under pressure and to a method for manufacturing a tank for containing a gas under pressure. The gases in question include, for example, but not limited to, natural gas, biogas, liquefied petroleum gas, and hydrogen.

[0002] The different functions of these reservoirs are to:

[0003] - to contain the gas under pressure, that is to say, to resist mechanically,

[0004] - ensure sealing against the outside,

[0005] - ensure filling with pressurized gas, using a solenoid valve mounted on the tip,

[0006] - deliver the pressurized gas using the same solenoid valve mounted on the nozzle,

[0007] - to attach to the supporting structure,

[0008] - to withstand the conditions of transport and use,

[0009] - to resist external environmental aggressions, both mechanical and thermal,

[0010] - to withstand the manufacturing conditions of the tanks.

[0011] These tanks can be mounted on all types of fixed or mobile equipment (road, rail, sea, air, and space vehicles). Pressurized gas tanks are manufactured from metallic materials or, more recently, from composite materials, for reasons of weight reduction and safety.

[0012] With regard to composite material tanks, also called composite tanks, their sealing is generally achieved by installing a container called a "liner" capable of sealing the container against its contents. Depending on the tank manufacturer, liners are available in metallic or plastic materials.

[0013] The "plastic" type liner includes at least one opening for filling and emptying the tank. It is manufactured by injection molding, rotational molding, or extrusion blow molding of a thermoplastic or thermosetting polymer material (abbreviated as "thermoset") such as, for example, polyethylene, polyamide, polyphthalamide, polyurethane, silicone, or polyoxymethylene. Advantageously, the thermoplastic polymer material is reinforced with fibers to form a composite material. The reinforcing fibers are, for example, glass fibers, carbon fibers, basalt fibers, aramid fibers, polymer fibers, etc. Silica fibers, polyethylene fibers, natural fibers, metallic fibers, metal alloy fibers, or ceramic fibers. These fibers increase the deformation resistance of the composite material. In a polymer material reinforced with fibers, the reinforcing fibers and the polymer material are intertwined to form a single, solid material. Such a composite material is described by the Applicant in its French patent application No. 18 72197, filed on November 30, 2018, and published under No. 3 089 160.

[0014] This liner is then covered with a liner reinforcement layer made of composite material, which will form the body of the tank, i.e., the tank's load-bearing structure, which must be able to withstand the pressures exerted by the fluid contained in the tank (hereinafter referred to as "internal pressure"). The reinforcement layer is not generally required to ensure the tank's watertightness.

[0015] This reinforcement envelope consists of:

[0016] - a reinforcement generally made of fibers, for example continuous fibers, of glass, of carbon, basalt, or other materials such as silica fibers or even plant fibers,

[0017] - a resin which is either deposited at the same time as the fiber (winding process) filamentary) or after the shell has been formed to create a dry "preform". This dry preform is then consolidated to give it the necessary rigidity. This consolidation is achieved by injecting resin, by infiltrating the preform with resin (infusion process), or by impregnating the resin under vacuum.

[0018] Advantageously, the reinforcing casing is coated with one or more layers of a fire-retardant material, preferably an intumescent fire-retardant material such as, for example, a silicate or phosphate-based coating. Silicate and phosphate are intumescent agents which, after exposure to fire, expand and create an insulating barrier. This improves the heat and fire resistance of the tank.

[0019] In all cases, during the manufacturing of the tank, a fitting is assembled to the liner with a watertight seal to allow for filling and fluid delivery. This fitting is generally made of metal (steel or aluminum). It is attached to a filling / emptying neck of the liner and has a flange for support against the liner. The fitting also has a threaded hole for mounting a solenoid valve. Such a fitting is described in US patent document 6230922.

[0020] When the reinforcing sleeve is deposited onto the liner by a filament winding process, the liner is held by a robotic arm or similar device at the tip. This can cause certain problems during the Implementation of the filament winding process. It should be noted that the filament winding process consists of applying successive layers of fibers wound helically and circumferentially onto the liner. If the filament winding is performed at high speed, significant torque is applied by the robot arm to the nozzle and to the connection between the nozzle and the liner, particularly during acceleration or deceleration phases that occur when applying layers of fibers wound along a helical trajectory. With a liner made of polyamide 6 (PA6), a conventional screw connection between the nozzle and the liner generally provides resistance to a maximum torque of between 200 and 400 Nm; this resistance is lower with a liner made of high-density polyethylene (HDPE).To accelerate the manufacturing speed of the tank, it is necessary to increase the torque resistance of the connection between the nozzle and the liner.

[0021] To increase this resistance, it is known to increase the axial span of the liner neck connected to the nozzle, thereby increasing the contact area between the nozzle and the liner neck. However, this results in an increase in the non-useful volume of the tank, i.e., the tank's overall size is increased without increasing its capacity to store pressurized gas at the liner neck, which is undesirable due to the limited space available in the vehicle. To prevent this increase in the tank's non-useful volume, it is known to change the shape of the liner so that the liner neck is axially offset towards the interior of the tank's internal volume. It is also known to change the shape of the liner so that the liner neck extends inwards towards the interior of the tank's internal volume and not outwards.

[0022] In both of the aforementioned cases, the axial dimension of the tank is reduced, and therefore its overall size. However, this comes with a drawback, as it creates a concave zone inside the tank around the base of the neck, generally referred to as the "dead volume." The presence of this concave zone considerably complicates the method of measuring the tank's mechanical resistance, carried out according to Regulation No. 134 of the United Nations Economic Commission for Europe (UNECE) concerning uniform provisions for the type approval of motor vehicles and their components with regard to the safety requirements for hydrogen-powered vehicles. This method involves injecting pressurized fluid into the tank and measuring the tank's deformation. After this procedure, it is necessary to completely empty the tank of the fluid used.Draining the concave area, which is difficult to access, is a particularly complex and time-consuming step, so it is preferable to avoid the presence of the concave area, or at the very least to reduce the volume as much as possible. of the concave zone. However, an increase in the axial span of the liner neck connected to the nozzle leads to an increase in the volume of the concave zone.

[0023] Another solution to increase resistance is to introduce glue between the nozzle and the liner, but this is a lengthy operation which slows down the manufacturing process of the tank and is difficult to control.

[0024] The invention aims, in particular, to increase the strength of the connection between the nozzle and the liner and to limit damage to the liner when the tank is pressurized. Optimally, this increase in the torque resistance of the connection between the nozzle and the liner is achieved without increasing the tank's size and without slowing down the tank manufacturing process.

[0025] To this end, the invention relates to a tank for containing a gas under pressure, comprising a plastic liner of generally cylindrical shape extending along a principal axis, comprising a neck surrounding an axial orifice of the liner, a reinforcing sleeve covering the liner, and a nozzle extending along the principal axis at least partially formed in the neck, the nozzle comprising at least: - an axial opening, - a first annular projection extending radially outwards from the tank relative to the axial opening, - a second annular projection extending radially outwards from the tank relative to the axial opening, the second annular projection being positioned axially outwards from the tank relative to the first annular projection, and - an external axial end extending at least partially outside the tank, characterized in that the tank further comprises a watertight contact surface between the nozzle and the neck of the liner, which extends between the first annular projection and the second annular projection, as well as a contact surface between the nozzle and the reinforcing casing, which extends axially between the second annular projection and the axial end of the nozzle.

[0026] Thanks to the fact that the tank includes a watertight contact surface between the nozzle and the liner neck, extending between the first annular projection (or first fin) and the second annular projection (or second fin), the liner is sandwiched between, on the one hand, the nozzle and, on the other hand, the reinforcing casing in a contact zone that forms a baffle. This limits the risk of liner degradation in an area near the tank opening. Indeed, when the tank is pressurized, static and dynamic forces are exerted on the liner neck by the nozzle. An example of liner degradation due to these forces Static stress is the creep of the liner's plastic material at the neck. An example of degradation due to dynamic stresses is fatigue of the liner's plastic material at the neck.

[0027] In addition to the aforementioned risks of liner degradation, excessive pressure in the tank, for example during hydraulic cycling tests of the tank as prescribed in Regulation No. 134 of the United Nations Economic Commission for Europe (UNECE), can cause degradation or even breakage of the nozzle. The invention also makes it possible to limit these risks.

[0028] Furthermore, the provision of a direct contact surface between the nozzle and the reinforcing sleeve, extending axially between the second annular protrusion and the axial end of the nozzle, creates a zone further from the tank opening. In this zone, a good mechanical connection is established between the reinforcing sleeve and the nozzle, and the liner is not sandwiched between the nozzle and the reinforcing sleeve. The presence of such a zone helps limit the risk of liner damage caused by the nozzle and the reinforcing sleeve. One example of liner damage is shearing of the liner by the nozzle and the reinforcing sleeve. Another example of liner damage is creep of the liner's plastic material.

[0029] Thus, the invention has the advantage of limiting the risk of liner degradation in the tank opening area, while also limiting the risk of liner degradation by the end fitting and the reinforcing sleeve, particularly by shearing of the liner by the end fitting and the reinforcing sleeve. Therefore, by increasing the strength of the connection between the end fitting and the liner, damage to the liner is prevented when the tank is pressurized, all without increasing the tank's size or slowing down the tank manufacturing process.

[0030] According to a preferred embodiment, the liner neck extends axially outwards from the tank relative to the liner's axial opening. This creates a contact surface between the liner neck and the reinforcing sleeve, which extends between the first and second annular projections. This arrangement ensures that the reinforcing sleeve absorbs the forces exerted on the liner neck by the nozzle when the tank is pressurized.

[0031] Preferably, the liner extends from the first annular projection to the second annular projection, covering at least a portion of the first annular projection. This further reduces, in an area near the tank opening, the risk of liner damage due to stresses exerted on it by the nozzle when the tank is pressurized. It also ensures a good seal at the tank opening.

[0032] In order to further limit the risks of degradation of the liner and to further improve the sealing at the opening of the tank, according to a particular embodiment, the liner covers at least a portion of the second annular projection.

[0033] In order to further limit the risks of degradation of the liner and to further improve the sealing at the opening of the tank, the liner completely covers the first annular protrusion.

[0034] Preferably, the contact surface between the tip and the reinforcing sleeve extends axially from the second annular projection to the axial end of the tip. This increases the contact surface between the tip and the reinforcing sleeve and ensures good mechanical contact between these two elements.

[0035] According to a preferred embodiment, the largest diameter of the first annular projection is less than or equal to the largest diameter of the second annular projection, preferably strictly less than the largest diameter of the second annular projection. This minimizes the mass of the tip by reducing its size.

[0036] According to a particular embodiment, a larger diameter of the first annular projection is strictly greater than a larger diameter of the second annular projection. This allows the nozzle to better resist breakage during hydraulic cycling tests of the tank according to Regulation No. 134 of the United Nations Economic Commission for Europe (UNECE).

[0037] According to a particular embodiment, the nozzle further comprises an inner axial end, opposite the outer axial end, which extends at least partially inside the tank. This makes it possible to maximize the usable volume of the tank in a confined environment.

[0038] According to a particular embodiment, the nozzle further comprises a third annular projection (or third fin) extending radially outwards from the tank relative to the axial opening, the third annular projection being positioned axially outwards from the tank relative to the second annular projection. This allows for better absorption, by the reinforcing casing, of the forces exerted on the liner neck by the nozzle when the tank is pressurized.

[0039] According to a particular embodiment, the larger diameter of the third annular projection is smaller than that of the second annular projection. This minimizes the mass of the tip.

[0040] According to a particular embodiment, the nozzle further comprises an annular shoulder extending radially outwards from the reservoir relative to the axial opening, the annular shoulder being arranged axially outwards from the reservoir relative to the third annular projection.

[0041] Preferably, the nozzle further comprises an external anchoring surface selected from the group including a rough surface, a non-symmetrical surface of revolution about the principal axis, an adhesive surface, and a combination of these surfaces, the external anchoring surface of the nozzle being a contact surface between the nozzle and the liner neck and / or a contact surface between the nozzle and the reinforcing sleeve. The presence of such an external anchoring surface strengthens the mechanical connection between the nozzle and the liner neck and thus increases the torque resistance of this connection. This makes it possible to carry out a rapid filament winding process involving significant acceleration and deceleration phases, thereby reducing the time and cost of manufacturing the tank.

[0042] A non-symmetrical surface of revolution around the principal axis is understood to be a surface whose cross-section in a plane perpendicular to the principal axis is not circular. It may, in particular, be a flat surface, or a cross-sectional surface having a polygonal contour, for example, hexagonal, toothed, crenellated, grooved, elliptical, etc.

[0043] The invention also relates to a method of manufacturing a tank intended to contain a gas under pressure, characterized in that it comprises the following steps: - providing a nozzle extending along a main axis, comprising an axial opening, a first annular projection extending radially outwards from the tank relative to the axial opening, a second annular projection extending radially outwards from the tank relative to the axial opening, the second annular projection being intended to be positioned axially outwards from the tank relative to the first annular projection, and an external end intended to extend at least partially outside the tank; - manufacture of a liner of general cylindrical shape extending along an axis, the liner comprising a neck surrounding an axial orifice of the liner; - fixing the nozzle to the liner, so that the nozzle is at least partially provided in the neck and that the neck extends along the main axis, and so as to create a watertight contact surface between the nozzle and the neck of the liner, which extends between the first annular projection and the second annular projection; - fixing a reinforcing sleeve to the liner and the nozzle, so that the reinforcing sleeve covers the liner, and so as to create a contact surface between the nozzle and the reinforcing sleeve, which extends axially between the second annular protrusion and the axial end of the nozzle.

[0044] According to a particular embodiment, the liner is made of plastic and the nozzle comprises an external anchoring surface selected from the group comprising a rough surface, a non-symmetrical surface of revolution about the principal axis, an adhesive surface, and a combination of these surfaces, wherein the step of attaching the nozzle to the liner includes an overmolding step of the liner neck onto the external anchoring surface of the nozzle during the liner manufacturing step, the liner preferably being manufactured by extrusion blow molding. This simplifies the manufacturing of the tank. The presence of the adhesive surface, in particular, improves the sealing of the watertight contact surface between the nozzle and the liner neck.

[0045] According to another particular embodiment, the liner is made of plastic and the nozzle comprises an external anchoring surface selected from the group comprising a rough surface, a non-symmetrical surface of revolution about the main axis, an adhesive surface and a combination of these surfaces, and wherein the step of fixing the nozzle to the liner comprises the following steps: - overmolding, on the external anchoring surface of the nozzle, of an intermediate layer of plastic material chemically compatible with the plastic material of the liner, the intermediate layer preferably being manufactured by injection molding, - overmolding of the liner neck onto the intermediate layer of plastic material during the liner manufacturing stage, the liner being preferably manufactured by extrusion blow molding.

[0046] By "chemically compatible," we mean that the first and second polymer materials each comprise chemical species that can be bonded together without the need for additional material. In other words, chemically compatible polymer materials are capable of bonding intimately with each other by fusion, and in particular of achieving molecular entanglement of polymer chains. Such molecular entanglement occurs through the application of heat at the point of contact.

[0047] Preferably, the rough surface of the tip is obtained by a step selected from engraving the external anchoring surface of the tip, machining the external anchoring surface of the tip, molding the external anchoring surface of the tip, knurling the external anchoring surface of the tip, and a combination of these steps, wherein the non-symmetrical surface of revolution about the principal axis of the tip is obtained by machining and / or molding the external anchoring surface of the tip, and wherein the adhesive surface of the tip is obtained by depositing an adhesive on the external anchoring surface of the tip or by activating the external anchoring surface of the tip. The engraving of the external anchoring surface The tip can be primed, for example, using a chemical etching agent or a laser. The adhesive surface of the tip can be applied by spraying or injection molding. Activation of the tip's external anchoring surface can be achieved by plasma, laser, or heating. This activation alters the surface tension of the tip's external anchoring surface, creating free radicals that form covalent or Van der Waals bonds with the liner's plastic, thus promoting mutual adhesion.

[0048] Preferably, the reinforcing sleeve being made of a composite material comprising a resin and reinforcing fibers, the step of fixing the reinforcing sleeve to the tip and the liner is a step of filament winding of the reinforcing sleeve on the liner and the tip during the step of manufacturing the reinforcing sleeve. Brief description of the figures

[0049] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[0050] [Fig. 1] is a local cross-sectional view along a median plane of the connection area of ​​a tank intended to contain a gas under pressure according to a first embodiment of the invention;

[0051] [Fig.2] is a cross-sectional view along plane ILII of [Fig. 1];

[0052] [Fig.3] is a perspective view of the nozzle of the reservoir of [Fig.1];

[0053] [Fig.4] is a bottom view of the tip of the [Fig.3];

[0054] [Fig.5] is a local cross-sectional view along a median plane of the connection zone of a reservoir intended to contain a gas under pressure according to a second embodiment of the invention;

[0055] [Fig.6] is a local cross-sectional view along a median plane of the connection area of ​​a tank intended to contain a gas under pressure according to a third embodiment of the invention;

[0056] [Fig.7] is a local cross-sectional view along a median plane of the connection area of ​​a tank intended to contain a gas under pressure according to a fourth embodiment of the invention;

[0057] [Fig.8] is a cross-sectional view along plane VIII-VIII of [Fig.7];

[0058] [Fig.9] is a perspective view of the nozzle of the reservoir of [Fig.7];

[0059] [Fig. 10] is a bottom view of the tip of the [Fig.9];

[0060] [Fig. 11] is a local cross-sectional view along a median plane of the area of connection of a tank intended to contain a gas under pressure according to a fifth embodiment of the invention;

[0061] [Fig. 12] is a cross-sectional view along plane XII-XII of [Fig. 11];

[0062] [Fig. 13] is a perspective view of the nozzle of the reservoir of [Fig. 11];

[0063] [Fig. 14] is a bottom view of the tip of the [Fig. 13];

[0064] [Fig. 15] is a local cross-sectional view along a median plane of the area of connection of a tank intended to contain a gas under pressure according to a sixth embodiment of the invention;

[0065] [Fig. 16] is a cross-sectional view along plane XVI-XVI of [Fig. 15];

[0066] [Fig. 17] is a perspective view of the nozzle of the reservoir of the [Fig. 15];

[0067] [Fig. 18] is a bottom view of the tip of the [Fig. 17]. Detailed description

[0068] Figure 1 shows a portion of a tank 10 intended to contain a gas under pressure according to a first embodiment of the invention. The tank 10 comprises a liner 12 made of plastic material defining an internal volume V of the tank intended to receive the gas under pressure.

[0069] The liner 12 here has a central portion of generally cylindrical or tubular shape, with reference to a principal axis XX of the reservoir 10, and two end portions, one of which is shown in [Fig. 1]. The end portion of the liner 12 shown includes a neck 14 surrounding an axial orifice 16 of the liner 12, which connects the internal volume V of the reservoir to the external environment, the neck 14 extending outwards from the internal volume V. The liner 12 is preferably manufactured by injection molding, rotomolding, or extrusion blow molding of a thermoplastic or thermoset polymer material, for example, polyamide or polyethylene, and the thickness of the liner 12 is, for example, less than or equal to 5 mm.

[0070] The tank 10 further includes a reinforcing envelope 18 covering the liner 12, preferably made of composite material, which will constitute the body of the tank 10, i.e. the resistant structure of the tank 10.

[0071] The reinforcing sheath 18 preferably comprises a reinforcement made of fibers, for example continuous fibers of glass, carbon, basalt, or others such as silica fibers or even plant fibers, and a resin which is either deposited at the same time as the fiber (for example by a filament winding process) or after the sheath has been formed to constitute a dry "preform". This dry preform is then consolidated to give it the necessary rigidity. This consolidation is carried out by means of resin injection or by means of resin infiltration through the said preform (infusion process), or by means of resin impregnation under vacuum.

[0072] Advantageously, the reinforcing casing 18 is coated with one or more layers of a flame-retardant material, preferably an intumescent flame-retardant material such as, for example, a silicate or phosphate-based coating. Silicate and phosphate are intumescent agents which, after exposure to fire, expand and create an insulating barrier. This improves the heat and fire resistance of tank 10.

[0073] The tank 10 also includes a nozzle 20 at least partially formed in the neck 14 of the liner 12. The nozzle 20 has a general shape with rotational symmetry about the principal axis XX. The nozzle 20 comprises a central portion extending partially inside the neck 14 of the liner 12 and a peripheral portion extending partially around the neck 14 of the liner 12 such that the neck 14 of the liner 12 is protected from the external environment by the nozzle 20. The nozzle 20 is a metal part, for example, made of aluminum. The nozzle 20 is notably configured to receive a solenoid valve (not shown in the figures) allowing the tank 10 to be alternately filled and emptied of its gas.

[0074] In all embodiments shown in the figures, the reservoir 10 further includes a sealed contact surface SG between the nozzle 20 and the neck 14 of the liner.

[0075] The nozzle 20 extends along the main axis XX and is at least partially formed in the neck 14. It has an axial opening 22 which extends along the main axis XX and is, for example, of substantially circular cross-section.

[0076] As can be seen in particular in Figures 1 and 3, the nozzle 20 further comprises an external axial end 24 extending at least partly outside the reservoir 10. The adjective "external" here refers to the volume V of the reservoir 10. The external axial end 24 is therefore located outside the neck 14 of the liner and is not covered by the reinforcing sleeve 18. The external axial end 24 comprises an annular shoulder 26 extending radially outwards from the reservoir relative to the axial opening 22.

[0077] The nozzle 20 further comprises an inner axial end 28, opposite the outer axial end 24, which extends at least partially inside the reservoir 10. The adjective "inner" here refers to the volume V of the reservoir 10. The inner axial end 28 is therefore located outside the neck 14 of the liner and is not covered by the reinforcing sleeve 18. It is located inside the volume V of the reservoir 10.

[0078] The nozzle 20 further comprises a first annular projection 31, or first fin 31, extending radially outwards from the reservoir 10 relative to the axial opening 22.

[0079] The first annular projection 31 preferably has radial symmetry around the principal axis XX. Its radial contour preferably has continuous curvature, i.e. does not have a sharp edge.

[0080] Preferably, the tip 20 further comprises an external anchoring surface SA selected from the group comprising a rough surface, a non-symmetrical surface of revolution around the principal axis XX, an adhesive surface and a combination of these surfaces.

[0081] A non-symmetrical surface of revolution about the principal axis XX is understood to be a surface whose cross-section in a plane perpendicular to the principal axis XX is not circular. It may, in particular, be a flat surface, or a cross-sectional surface having a polygonal contour, for example, hexagonal, toothed, crenellated, grooved, elliptical, etc.

[0082] The presence of such an external anchoring surface SA makes it possible to strengthen the mechanical connection between the end piece 20 and the neck 14 of the liner 12 and thus to increase the torque resistance of this connection.

[0083] In the first three embodiments shown in figures 1 to 6, the first annular projection 31 carries such an external anchoring surface SA which is a non-symmetrical surface of revolution around the main axis XX.

[0084] Indeed, in these first three embodiments, the external anchoring surface SA locally has a cross-section, along a plane perpendicular to the axis XX, in this case in the cutting plane II-II, in the shape of a toothed wheel, as can be seen in particular in Figures 2 to 4, that is to say, it comprises a plurality of teeth 29 projecting from the first annular projection 31 extending radially outwards from the reservoir 10. Preferably, the teeth 29 are distributed symmetrically around the axis XX. The number of teeth 29 of the wheel is here twelve, but this number can naturally vary. The shape of the teeth 29 is also substantially rectangular in this plane II-II, but can also vary.

[0085] The external anchoring surface SA is therefore in these first three embodiments formed of a succession of hollows (the spaces between the teeth 29) and protrusions (the teeth 29), which makes it possible to strengthen the mechanical connection between the tip 20 and the neck 14 of the liner 12 and thus to increase the torque resistance of this connection.

[0086] The external anchoring surface SA here forms a portion of the contact surface SG between the neck 14 and the nozzle 20, but it could form the entire contact surface SG. The proportion between the external anchoring surface SA and the contact surface SG between the nozzle 20 and the neck 14 can naturally vary according to requirements.

[0087] The nozzle 20 also includes a second annular projection 32, or second fin 32, extending radially outwards from the reservoir 10 relative to the axial opening 22. The second annular projection 32 is arranged axially towards the outside of the reservoir 10 relative to the first annular projection 31, that is to say towards the top of the figures relative to the first annular projection 31.

[0088] The second annular projection 32 preferably has radial symmetry about the principal axis XX. Its radial contour preferably has a continuous curvature, i.e., it does not have a sharp edge. In all embodiments shown in the figures, its cross-section along a plane perpendicular to the axis XX is substantially circular. Naturally, the shape of the second annular projection 32 can vary.

[0089] In the first embodiment of the invention shown in figures 1 to 4, a larger diameter DI of the first annular projection 31 is strictly greater than a larger diameter D2 of the second annular projection 32.

[0090] However, according to a second embodiment of the invention illustrated in [Fig.5], a larger diameter DI of the first annular projection 31 is substantially equal to a larger diameter D2 of the second annular projection 32. The reservoir 10 is otherwise identical to that of the first embodiment.

[0091] According to a third embodiment of the invention illustrated in [Fig.6], a larger diameter DI of the first annular projection 31 is less than or equal to a larger diameter D2 of the second annular projection 32, preferably strictly less than a larger diameter of the second annular projection 32. The reservoir 10 is otherwise identical to that of the first embodiment.

[0092] In all embodiments shown in the figures, the watertight contact surface SG between the nozzle 20 and the neck 14 of the liner extends between the first annular projection 31 and the second annular projection 32, as can be seen in figures 1, 5, 7, 11 and 15.

[0093] According to a particular embodiment, the nozzle further comprises a third annular projection (or third fin) 33 extending radially outwards from the reservoir 10 relative to the axial opening 22. The third annular projection 33 is arranged axially outwards from the reservoir 10 relative to the second annular projection 32, i.e. towards the top of the figures relative to the second annular projection 32.

[0094] The third annular projection 33 preferably has radial symmetry about the principal axis XX. Its radial contour preferably has a continuous curvature, i.e., it does not have a sharp edge. In all embodiments shown in the figures, its cross-section along a plane perpendicular to the axis XX is substantially circular. Naturally, the shape of the second annular projection 32 can vary.

[0095] In all embodiments illustrated in the figures, a larger diameter D3 of the third annular projection 33 is smaller than that of the second annular projection 32, as can be seen in figures 1, 5, 7, 11 and 15. However, it is possible to vary this diameter according to needs.

[0096] In all embodiments shown in the figures, the reservoir 10 also includes a contact surface SE between the nozzle 20 and the reinforcing sleeve 18, which extends axially between the second annular projection 32 and the outer axial end 24 of the nozzle 20, as can be seen in Figures 1, 5, 7, 11 and 15.

[0097] In all embodiments illustrated in the figures, the neck 14 of the liner 12 extends axially outwards from the tank 10 relative to the axial orifice 16 of the liner 12. This makes it possible to create a contact surface between the neck 14 of the liner 12 and the reinforcing casing 18, which extends between the first annular projection 31 and the second annular projection 32.

[0098] Preferably, the liner 12 extends from the first annular projection 31 to the second annular projection 32, covering at least a portion of the first annular projection 31. This further limits, in an area near the opening of the reservoir 10, the risk of damage to the liner 12 due to the forces exerted on it by the nozzle 20 when the reservoir 10 is pressurized. It also ensures a good seal at the opening of the reservoir 10.

[0099] In order to further limit the risks of degradation of the liner 12 and to further improve the sealing at the opening of the tank 10, in all embodiments shown in the figures, the liner 12 covers at least a portion of the second annular projection 32, as can be seen in figures 1, 5, 7, 11 and 15.

[0100] In order to further limit the risks of degradation of the liner 12 and to further improve the sealing at the opening of the tank 10, in all embodiments shown in the figures, the liner 12 completely covers the first annular projection, as can be seen in figures 1, 5, 7, 11 and 15.

[0101] Preferably, the contact surface SE between the tip 20 and the reinforcing sleeve 18 extends axially from the second annular projection to the axial end of the tip 20. This increases the contact surface SE between the tip 20 and the reinforcing sleeve 18 and ensures good mechanical contact between these two elements.

[0102] In an embodiment not shown in the figures, the external anchoring surface SA forms a portion of the contact surface SE between the end piece 20 and the reinforcing sleeve 18, or the entire contact surface SE between the end piece 20 and the reinforcing sleeve 18. In yet another embodiment not shown in the figures, the end piece 20 comprises two external anchoring surfaces SA which respectively form a portion, or the entirety, of the sealed contact surface SG between the neck 14 of the liner 12 and the nozzle 20 and of the contact surface SE between the nozzle 20 and the reinforcing sleeve 18.

[0103] In a fourth embodiment illustrated in figures 7 to 10, the first annular projection 31 has a hexagonal cross-section along a plane perpendicular to the principal axis XX, in this case the plane of its largest diameter, i.e. the plane VIII-VIII.

[0104] The first annular projection 31 thus presents, as can be seen in figures 8 and 10, six substantially flat faces 34 distributed symmetrically around the main axis XX, the union of which forms an external anchoring surface SA not symmetrical of revolution around the main axis XX.

[0105] In a fifth embodiment illustrated in Figures 11 to 14, the first annular projection 31 comprises, around its periphery, a plurality of lateral notches 36. The lateral notches 36 here have a T-shaped cross-section in a plane perpendicular to the principal axis XX, in this case the plane of its largest diameter, here plane XILXII as can be seen in [Fig. 14]. When viewed from the side of the end piece 20, as in [Fig. 13], the lateral notches 36 have the shape of a capital I. The lateral notches 36 are preferably distributed symmetrically around the axis XX. For example, there are nine of them, but this number can naturally vary.

[0106] The first annular projection 31 thus presents an external anchoring surface SA that is not symmetrical in revolution around the main axis XX.

[0107] In a sixth embodiment illustrated in figures 11 to 14, the first annular projection 31 has an oval cross-section along a plane perpendicular to the principal axis XX, in this case the plane of its largest diameter, i.e. the plane XVLXVI.

[0108] The first annular projection 31 thus presents, as can be seen in figures 8 and 10, oblong faces 38 whose union forms an external anchoring surface SA not symmetrical of revolution around the main axis XX.

[0109] We will now describe an example of a manufacturing process for a tank 10.

[0110] In a first step, a nozzle such as the nozzle 20 is provided, that is to say extending along a principal axis XX, comprising an axial opening 22, a first annular projection 31 extending radially outwards from the reservoir 10 relative to the axial opening 22, a second annular projection 32 extending radially outwards from the reservoir 10 relative to the axial opening 22, the second annular projection 32 being intended to be disposed axially outwards from the reservoir 10 relative to the first annular projection 31, and an external axial end 24 intended to extend at least partly outwards from the reservoir 10.

[0111] Where the tip 20 comprises an external anchoring surface SA including a rough surface, the latter is obtained by a step selected from engraving the external anchoring surface SA of the tip, machining the external anchoring surface of the tip, molding the external anchoring surface SA of the tip, knurling the external anchoring surface SA of the tip, and a combination of these steps, wherein the non-symmetrical surface of revolution about the principal axis of the tip XX is obtained by machining and / or molding the external anchoring surface SA of the tip, and wherein the adhesive surface of the tip is obtained by depositing an adhesive on the external anchoring surface SA of the tip or by activating the external anchoring surface SA of the tip. The engraving of the external anchoring surface SA of the tip can be carried out, for example, using a chemical etching agent or a laser.The adhesive surface of the tip can be applied by spraying or injection molding. Activation of the tip's external SA anchoring surface can be achieved by plasma, laser, or heating.

[0112] A liner 12 of generally cylindrical shape extending along an axis XX is then manufactured. This liner 12 includes a neck 14 surrounding an axial orifice 16 of the liner 12. The liner 12 is for example made of plastic and preferably manufactured by extrusion blow molding.

[0113] The nozzle 20 is then fixed to the liner 12, so that the nozzle 20 is at least partially provided in the neck 14 and the neck 14 extends along the main axis XX, and so as to create a watertight contact surface SG between the nozzle 20 and the neck 14 of the liner 12, which extends between the first annular projection 31 and the second annular projection 32. This step of fixing the nozzle 20 to the liner 12 may in particular include a step of overmolding the neck 14 of the liner 12 onto the external anchoring surface SA of the nozzle during the manufacturing step of the liner 12.

[0114] In one embodiment, the nozzle 20 is fixed to the liner 12 by overmolding, on the external anchoring surface SA of the nozzle, an intermediate layer of plastic material chemically compatible with the plastic material of the liner 12, the intermediate layer being preferably manufactured by injection molding, and by overmolding the neck 14 of the liner 12 on the intermediate layer of plastic material during the manufacturing step of the liner 12.

[0115] A reinforcing sleeve 18 is then fixed to the liner 12 and to the nozzle 20, so that the reinforcing sleeve 18 covers the liner 12, and so as to create a contact surface SE between the nozzle 20 and the reinforcing sleeve 18, which extends axially between the second annular projection 32 and the outer axial end 24 of the nozzle 20. Preferably, the reinforcing sleeve 18 is made of a composite material comprising a resin and reinforcing fibers.

[0116] Preferably also, the attachment of the reinforcing sleeve 18 to the tip 20 and to the liner 12 is a filament winding step of the reinforcing sleeve 18 on the liner and the tip 20 during the manufacturing step of the reinforcing sleeve 18.

[0117] The invention is not limited to the embodiments shown, and other embodiments will be obvious to those skilled in the art. In particular, it may be possible to vary the largest diameters of the first, second, and third annular projections in the fourth, fifth, and sixth embodiments in the same way as in the first, second, and third embodiments. Reference list

[0118] 10: Reservoir 12: Liner 14: Bottleneck 16: Axial orifice of the liner 18: Reinforcement envelope 20: Nozzle 22: Axial opening of the nozzle 24: Outer axial end of the tip 26: Annular shoulder of the tip 28: Inner axial end of the tip 29: Teeth of the first annular projection 31: First annular projection of the tip 32: Second annular projection of the tip 33: Third annular projection of the tip 34: Faces of the hexagon 36: Side notches 38: Oblong faces DI: Largest diameter of the first annular projection D2: Largest diameter of the second annular projection D3: Largest diameter of the third annular projection; V: Internal volume of the reservoir SA: External anchoring surface of the tip SE: Contact surface between the tip and the reinforcing casing SG: Contact surface between the neck and the nozzle XX: Main axis of the reservoir

Claims

Demands

1. A tank (10) for containing a pressurized gas, comprising a liner (12) made of plastic, generally cylindrical in shape, extending along a principal axis (XX), including a neck (14) surrounding an axial opening (16) of the liner (12), a reinforcing sleeve (18) covering the liner (12), and a nozzle (20) extending along the principal axis (XX) at least partially formed in the neck (14), the nozzle (20) comprising at least: - an axial opening (22), - a first annular projection (31) extending radially outward from the tank (10) relative to the axial opening (22), - a second annular projection (32) extending radially outward from the tank (10) relative to the axial opening (22), the second annular projection (32) being disposed axially towards the outside of the reservoir (10) relative to the first annular projection (31),and - an external axial end (24) extending at least partially outside the reservoir (10), characterized in that the reservoir (10) further comprises a watertight contact surface (SG) between the nozzle (20) and the neck (14) of the liner (12), which extends between the first annular projection (31) and the second annular projection (32), as well as a contact surface (SE) between the nozzle and the reinforcing sleeve (18), which extends axially from the second annular projection (32) to the external axial end (24) of the nozzle (20), the liner (12) extending from the first annular projection (31) to the second annular projection (32), covering at least a portion of the first annular projection (31).

2. Reservoir (10) according to the preceding claim, in which the neck (14) of the liner (12) extends axially outwards from the reservoir (10) relative to the axial orifice (16) of the liner (12).

3. Tank (10) according to any one of the preceding claims, in which the liner (12) covers at least a portion of the second annular projection (32).

4. Tank (10) according to any one of the preceding claims, in which the liner (12) completely covers the first annular projection (31).

5. Reservoir (10) according to any one of the preceding claims, wherein a larger diameter of the first annular projection (31) is less than or equal to a larger diameter of the second annular projection (32), preferably strictly less than a larger diameter of the second annular projection (32).

6. Reservoir (10) according to any one of claims 1 to 4, wherein a larger diameter of the first annular projection (31) is strictly greater than a larger diameter of the second annular projection (32).

7. Reservoir (10) according to any one of the preceding claims, wherein the nozzle (20) further comprises a third annular projection (33) extending radially outwards from the reservoir (10) relative to the axial opening (22), the third annular projection (33) being arranged axially outwards from the reservoir (10) relative to the second annular projection (32).

8. Tank (10) according to any one of the preceding claims, wherein the nozzle (20) further comprises an external anchoring surface (SA) selected from the group comprising a rough surface, a non-symmetrical surface of revolution about the principal axis (XX), an adhesive surface and a combination of these surfaces, the external anchoring surface (SA) of the nozzle being a contact surface (SG) between the nozzle (20) and the neck (14) of the liner (12) and / or a contact surface (SE) between the nozzle (20) and the reinforcing sleeve (18).

9. Method of manufacturing a tank (10) intended to contain a gas under pressure, characterized in that it comprises the following steps: - providing a nozzle (20) extending along a principal axis (XX), comprising an axial opening (22), a first annular projection (31) extending radially outwards from the tank (10) relative to the axial opening (22), a second annular projection (32) extending radially outwards from the tank (10) relative to the axial opening (22), the second annular projection (32) being intended to be arranged axially outwards from the tank (10) relative to the first annular projection (31), and an external axial end (24) intended to extend at least partially outwards from the tank (10); - manufacture of a liner (12) of general cylindrical shape extending along an axis (XX), the liner comprising a neck (14) surrounding an axial orifice (16) of the liner (12); - fixing the nozzle (20) to the liner (12), so that the nozzle (20) is at least partially provided in the neck (14) and that the neck (14) extends along the main axis (XX), that the liner (12) extends from the first annular projection (31) to the second annular projection (32) covering at least a portion of the first annular projection (31) and so as to create a watertight contact surface (SG) between the nozzle (20) and the neck (14) of the liner (12), which extends between the first annular projection (31) and the second annular projection (32);- fixing a reinforcing sleeve (18) to the liner (12) and to the nozzle (20), so that the reinforcing sleeve (18) covers the liner (12), and so as to create a contact surface (SE) between the nozzle (20) and the reinforcing sleeve (18), which extends axially between the second annular projection (32) and the outer axial end (24) of the nozzle (20).

10. A method according to claim 9, wherein the liner (12) is made of plastic and the nozzle (20) comprises an external anchoring surface (SA) selected from the group comprising a rough surface, a non-symmetrical surface of revolution about the principal axis, an adhesive surface and a combination of these surfaces, and wherein the step of attaching the nozzle (20) to the liner (12) comprises a step of overmolding the neck (14) of the liner (12) onto the external anchoring surface (SA) of the nozzle during the manufacturing step of the liner (12), the liner (12) preferably being manufactured by extrusion blow molding.

11. A method according to claim 9, wherein the liner (12) is made of plastic and the nozzle (20) comprises an external anchoring surface (SA) selected from the group comprising a rough surface, a non-symmetrical surface of revolution about the principal axis, an adhesive surface, and a combination of these surfaces, and wherein the step of attaching the nozzle (20) to the liner (12) comprises the following steps: - overmolding, onto the external anchoring surface (SA) of the nozzle, an intermediate layer of plastic material chemically compatible with the plastic material of the liner (12), the layer intermediate, preferably manufactured by injection molding, - overmolding of the neck (14) of the liner (12) on the intermediate layer of plastic material during the manufacturing step of the liner (12), the liner (12) being preferably manufactured by extrusion blow molding.

12. A method according to any one of claims 11 to 12, wherein the rough surface of the tip (20) is obtained by a step selected from engraving the external anchoring surface of the tip, machining the external anchoring surface (SA) of the tip, molding the external anchoring surface (SA) of the tip, knurling the external anchoring surface (SA) of the tip and a combination of these steps, wherein the non-symmetrical surface of revolution about the principal axis (XX) of the tip is obtained by machining and / or molding the external anchoring surface of the tip, and wherein the adhesive surface of the tip is obtained by depositing an adhesive on the external anchoring surface (SA) of the tip or by activating the external anchoring surface (SA) of the tip.

13. A method according to any one of claims 10 to 12, wherein the reinforcing sleeve (18) is made of a composite material comprising a resin and reinforcing fibers, the step of attaching the reinforcing sleeve (18) to the nozzle (20) and the liner (12) is a step of filament winding the reinforcing sleeve (18) onto the liner (12) and the nozzle (20) during the step of manufacturing the reinforcing sleeve (18).

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