A tank designed to contain a gas under pressure.

Abstract

This tank (2) for containing a pressurized gas comprises a liner (4) made of plastic, generally cylindrical in shape, having a main axis (5). The liner (4) includes a neck (6) surrounding an axial opening in the liner (4). The tank further comprises a nozzle (8) at least partially formed in the neck (6) of the liner (4), a reinforcing ring (14) for the liner neck that is integral with and permanently attached to the neck (6) of the liner (4), and means (24) for attaching the nozzle (8) to the reinforcing ring (14) of the liner neck. (See Figure 1 for abbreviations.)

Description

Title of the invention: Tank intended to contain a gas under pressure

[0001] The invention relates to tanks intended to contain pressurized gases, in particular tanks installed in motor vehicles. The invention relates more specifically to a tank intended to contain a pressurized gas and to a method of manufacturing a tank intended to contain a pressurized gas. The gases in question are, for example, and not limited to, natural gas, biogas, liquefied petroleum gas, hydrogen.

[0002] The different functions of these tanks are:

[0003] - contain the gas under pressure, i.e. mechanically resist,

[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] - attach to the supporting structure,

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

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

[0010] - resist the manufacturing conditions of the tanks.

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

[0012] As regards composite tanks, their sealing is generally achieved by installing a container called a "liner" capable of ensuring the sealing of the container with respect to the contents. Depending on the tank manufacturers, liners are offered in metallic materials or plastic materials.

[0013] The “plastic” type liner comprises at least one opening for filling and emptying the tank. It is manufactured by injection or rotational molding or by extrusion-blow molding of a thermoplastic or thermosetting polymer material (abbreviated as “thermodur”) such as, for example, polyethylene, polyamide, polyphthalamide, polyurethane, silicone, polyoxymethylene. Advantageously, the thermoplastic polymer material is loaded with reinforcing fibers to constitute a composite material. The reinforcing fibers are, for example, glass fibers, carbon fibers, basalt fibers, aramid fibers, polymer fibers, silica fibers, polyethylene fibers, natural fibers, metal fibers, metal alloy fibers or ceramic fibers. These fibers make it possible to increase the deformation resistance of the composite material. In a polymer material loaded with reinforcing fibers, the reinforcing fibers and the polymer material are entangled to form a single-piece 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] Alternatively, the liner is manufactured by filament winding. An example of manufacturing a container by filament winding is described in patent document FR1431135A.

[0015] This liner is then covered with a liner reinforcement envelope made of composite material which will constitute the body of the tank, i.e. the resistant structure of the tank, which must be capable of resisting the pressures exerted by the fluid contained in the tank (hereinafter referred to as "internal pressure"). The reinforcement envelope is generally not required to ensure the sealing of the tank.

[0016] This reinforcement envelope is made up of:

[0017] - a reinforcement generally made up of fibers, for example continuous, of glass, carbon, basalt, or others such as silica fibers or even plant fibers,

[0018] - a resin which is either deposited at the same time as the fiber (winding process filamentary) or after the envelope has been produced to form a dry "preform". This dry preform is then consolidated to give it the necessary rigidity. This consolidation is carried out using resin injection or by infiltration of this resin through the said preform (infusion process), or by vacuum impregnation of resin.

[0019] Advantageously, the reinforcing shell 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.

[0020] In all cases, at the time of manufacturing the tank, a nozzle is assembled to seal the liner to allow the filling and delivery of the fluid. This nozzle is generally made of metal (steel or aluminum). It is attached to a filling / emptying neck of the liner and has a collar for bearing against the liner. The nozzle also has a thread allowing a solenoid valve to be mounted on the nozzle. Such a nozzle is described in patent document US6230922.

[0021] When the reinforcing envelope is deposited on the liner by a filament winding process, the liner is held by a robot arm or a similar device at the tip. This can pose certain problems during the implementation of the filament winding process. It is recalled that the filament winding process consists of applying successive layers of fibers wound helically and circumferentially on the liner. If the filament winding is carried out at a high speed, a significant torque is applied by the robot arm to the tip and to the connection between the tip and the liner, in particular during acceleration or deceleration phases which occur during the application of layers of fibers wound according to a helical trajectory.With a liner made of polyamide 6 (PA6), a classic screw connection between the end piece and the liner generally allows to obtain a resistance to a maximum torque between 200 and 400 Nm, this resistance is lower with a liner made of high density polyethylene (HDPE). In order to accelerate the manufacturing speed of the tank, it is necessary to increase the torque resistance of the connection between the end piece and the liner.

[0022] In order to increase this resistance, it is known to increase the axial span of the neck of the liner connected to the end piece, in order to increase the connection surface between the end piece and the neck of the liner. However, this results in an increase in the non-useful volume of the tank, that is to say that the size of the tank is increased without increasing its capacity to store gas under pressure, at the neck of the liner, which is desirable to avoid due to the small space available in the vehicle. To prevent the increase in the non-useful volume of the tank, it is known to change the shape of the liner so that the neck of the liner is axially offset towards the inside of the internal volume of the tank. It is also known to change the shape of the liner so that the neck of the liner extends towards the inside of the internal volume of the tank and not towards the outside of the internal volume of the tank.

[0023] In both of the above cases, the axial dimension of the tank and therefore the bulk of the tank are reduced. But this comes with a drawback, in the sense that a concave zone is thus generated inside the tank around the base of the neck, generally called "dead volume". The presence of this concave zone considerably complicates the method for measuring the mechanical strength of the tank, carried out according to Regulation No. 134 of the United Nations Economic Commission for Europe (UNECE) concerning uniform provisions for the approval of motor vehicles and their components with regard to the safety requirements for vehicles powered by hydrogen, according to which pressurized fluid is injected inside the tank and the deformation of the tank is measured. After implementing this method, it is necessary to completely empty the tank of the fluid used.Draining the concave area, which is difficult to access, is a . This is a particularly complex and time-consuming step, so it is preferable to avoid the presence of the concave zone, or at least to reduce the volume of the concave zone as much as possible. 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.

[0024] Another solution to increase resistance is to introduce glue between the tip and the liner, but this is a long operation which slows down the tank manufacturing process and is difficult to control.

[0025] An object of the invention is to increase the torque strength of the connection between the end piece and the liner. Optimally, this increase in the torque strength of the connection between the end piece and the liner is obtained without increasing the size of the tank and without slowing down the manufacturing process of the tank.

[0026] To this end, according to the invention, there is provided a tank intended to contain a pressurized gas comprising a plastic liner of generally cylindrical shape having a main axis, the liner comprising a neck surrounding an axial opening of the liner, the tank comprising: - a nozzle at least partially provided in the neck of the liner, - a reinforcing ring for the neck of the liner, secured and non-removable from the neck of the liner, and - means of fixing, possibly removable, the end piece to the reinforcing ring of the liner neck.

[0027] The expression "a liner neck reinforcement ring integral with and irremovable from the liner neck" means that the liner neck reinforcement ring is coupled in a fixed and permanent manner to the liner neck.

[0028] Thus, the presence of the integral and non-removable reinforcing ring of the liner neck makes it possible to reinforce the mechanical connection between the end piece and the liner neck and thus to increase the torque resistance of this connection which can exceed 500 Nm. This thus makes it possible to carry out a rapid filament winding process implementing significant acceleration and deceleration phases, and therefore to reduce the time and cost of manufacturing the tank. In addition, the presence of the means for fixing the end piece to the reinforcing ring of the liner neck means that the fixing of the various elements is done within the axial span of the liner neck and not outside it. In other words, the presence of the reinforcing ring of the liner and the fixing of the end piece to the reinforcing ring of the liner neck does not have the effect of increasing the axial size of the tank.Therefore, the non-useful volume of the tank is not increased in the case where the neck of the liner is oriented towards the outside of the internal volume of the tank, and the dead volume of the tank is not increased in the case where the neck of the liner is axially offset, respectively oriented, towards the inside of the internal volume of the tank.

[0029] According to a preferred embodiment of the invention, the neck of the liner is overmolded onto the reinforcing ring. In the case where the neck of the liner is oriented towards the outside of the internal volume of the tank, the reinforcing ring is overmolded from the outside into the neck of the liner. In the case where the neck of the liner is oriented towards the inside of the internal volume of the tank, the reinforcing ring is overmolded from the inside around the neck of the liner.

[0030] The reinforcement ring is thus made integral and non-removable from the neck of the liner in a simple and effective manner.

[0031] According to one embodiment of the invention, the neck of the liner extends towards the outside of an internal volume of the tank, and the reinforcing ring is at least partially formed in the neck of the liner, and the fixing means are located radially relative to the neck of the liner, inside the neck of the liner, so that the reinforcing ring is positioned between the neck of the liner and the end piece.

[0032] According to an alternative embodiment of the invention, the neck of the liner extends towards the inside of an internal volume of the tank, and the reinforcing ring is at least partially arranged around the neck of the liner, and the fixing means are located in an axial extension of the neck of the liner, respectively radially relative to the neck of the liner, in the direction of the internal volume of the tank, respectively inside the neck of the liner, so that the neck of the liner is positioned between the reinforcing ring and the end piece.

[0033] The invention can thus be implemented in several possible configurations for the liner, which contributes to making the invention easily implementable industrially.

[0034] Advantageously, the reinforcing ring is made from a material having a breaking stress or an elastic limit which is at least twice that of the material from which the liner is made.

[0035] This ensures that the reinforcing ring makes it possible to considerably increase the mechanical resistance of the neck of the liner.

[0036] Preferably, the reinforcing ring is made of metal, such as aluminum or stainless steel, thermoplastic material or thermosetting material.

[0037] The reinforcement ring is thus made with relatively inexpensive and easily accessible materials.

[0038] Advantageously, the fixing means are configured to provide mechanical anchoring of the end piece to the reinforcing ring, for example by screwing or by snap-fastening.

[0039] This ensures good mechanical fixing between the tip and the reinforcement ring, using simple and inexpensive means.

[0040] Advantageously, the reinforcement ring comprises a shoulder for cooperation with the tip configured to receive an axial end of the tip.

[0041] The reinforcing ring thus makes it possible to form an axial stop making it easier to position the end piece in relation to the reinforcing ring, and therefore to ensure good fixing between these two elements, with simple means not requiring an additional part specifically dedicated to this function.

[0042] Advantageously, the neck of the liner comprises a shoulder for cooperation with the end piece configured to receive an axial end of the end piece.

[0043] The neck of the liner thus makes it possible to form an axial stop making it possible to ensure the correct positioning of the end piece relative to the neck of the liner, with simple means not requiring an additional part specifically dedicated to this function.

[0044] Advantageously, the reinforcing ring comprises a shoulder for cooperation with the liner configured to receive a complementary shoulder provided on the liner, at the base of the neck.

[0045] The mechanical anchoring of the reinforcing ring in the neck of the liner is thus improved, with simple means that do not require an additional part specifically dedicated to this function. This improvement in the mechanical anchoring of the reinforcing ring in the neck of the liner makes it possible to increase the torque resistance of the connection between the end piece and the liner, which makes it possible to accelerate the speed of filament winding and therefore the speed of manufacturing of the tank.

[0046] Advantageously, the end piece comprises an annular seal bearing tightly against the neck of the liner, the annular seal being housed in a cavity of the end piece. Preferably, the cavity of the end piece is closed by a ring in order to form a groove for housing the annular seal. Preferably, the ring is a removable ring.

[0047] This ensures that the connection between the end piece and the neck of the liner is properly sealed, and the ring makes it easier to install the annular seal between the end piece and the neck of the liner.

[0048] Advantageously, the reservoir further comprises a sealed contact surface between the end piece and the neck of the liner. For example, the neck of the liner and the end piece each have a smooth bearing surface together forming the sealed contact surface between the end piece and the neck of the liner. In another example, a layer of a gas-tight material constitutes the sealed contact surface between the end piece and the neck of the liner, for example, a layer of glue applied between the end piece and the neck of the liner.

[0049] The invention can thus be implemented in several possible configurations with regard to the sealing of the connection between the end piece and the neck of the liner, which contributes to making the invention easily adaptable industrially.

[0050] Advantageously, the reinforcing ring comprises, on its external or internal radial surface, axial grooves.

[0051] This further improves the mechanical anchoring of the reinforcement ring in the neck of the liner.

[0052] Preferably, the reinforcing ring has, on the same surface as that comprising the axial grooves, a strip of uniform radius separating the axial grooves into two sets of axial grooves separated by the strip, and the annular seal is in leaktight abutment against a bearing zone of the neck of the liner in contact with the strip of the reinforcing ring integral and non-removable from the neck of the liner.

[0053] Indeed, the annular seal exerts a permanent contact pressure on the neck of the liner in order to maintain the tightness of the tank, this contact pressure tends to cause the material of the neck of the liner located in the support zone to flow. The presence of the strip makes it possible to homogenize the fining undergone by the support zone of the neck of the liner when the tank is in service. Thus, the risks of leakage under the effect of fining are reduced and the service life of the tank is increased.

[0054] The invention also provides a method of manufacturing a tank intended to contain a gas under pressure, characterized in that it comprises the following steps: - manufacture of a liner of generally cylindrical shape having a main axis, the liner comprising a neck surrounding an axial opening of the liner and extending towards the outside of an internal volume of the tank, - fixing a reinforcing ring of the liner neck in the liner neck, - inserting a nozzle at least partially into the liner neck, and - fixing the nozzle to the reinforcing ring using fixing means located radially relative to the liner neck, inside the liner neck, so that the reinforcing ring is positioned between the liner neck and the nozzle.

[0055] The invention also provides a method for manufacturing a tank intended to contain a pressurized gas, characterized in that it comprises the following steps: - manufacturing a liner of generally cylindrical shape having a main axis, the liner comprising a neck surrounding an axial opening of the liner and extending towards the interior of an internal volume of the tank, - fixing a reinforcing ring of the liner neck around the liner neck, - inserting a nozzle at least partially into the liner neck, and - fixing the nozzle to the reinforcing ring using fixing means located in an axial extension of the liner neck, respectively radially relative to the liner neck, in the direction of the internal volume of the tank, respectively inside the liner neck, so that the liner neck is positioned between the reinforcing ring and the nozzle.

[0056] According to one embodiment of the invention, the liner is made of plastic and the step of fixing the reinforcing ring of the liner neck to the liner neck is a step of overmolding the liner neck onto the reinforcing ring during the liner manufacturing step. Brief description of the figures

[0057] The invention will be better understood on reading the following description given solely by way of example and with reference to the appended drawings in which:

[0058] [Fig-1] [Fig.l] is a sectional view of a tank intended to contain a gas under pressure according to a first embodiment of the invention,

[0059] [Fig.2] Figures 2A and 2B are sectional views of the tank of [Fig.l] according to two variants of realization,

[0060] [Fig.3] [Fig.3] is a perspective view of a reinforcing ring included in the reservoir of [Fig.l],

[0061] [Fig.4] Figures 4A, 4B and 4C are perspective views of reinforcement rings according to alternative embodiments of the invention,

[0062] [Fig.5] [Fig.5] is a sectional view of a tank intended to contain a gas under pressure according to a second embodiment of the invention,

[0063] [Fig.6] [Fig.6] is a sectional view of a tank intended to contain a gas under pressure according to a third embodiment of the invention,

[0064] [Fig.7] [Fig.7] is a sectional view of a tank intended to contain a gas under pressure according to a fourth embodiment of the invention,

[0065] [Fig.8] [Fig.8] is a sectional view of a tank intended to contain a gas under pressure according to a fifth embodiment of the invention,

[0066] [Fig.9] [Fig.9] is a sectional view of a tank intended to contain a gas under pressure according to a sixth embodiment of the invention,

[0067] [Fig. 10] [Fig. 10] is a sectional view of a tank intended to contain a pressurized gas according to a seventh embodiment of the invention, and

[0068] [Fig. 11] [Fig. 11] is a sectional view of a tank intended to contain a pressurized gas according to the state of the art.

[0069] [Fig.l] shows a tank 2 intended to contain a pressurized gas according to a first embodiment of the invention. The tank 2 comprises a liner 4 made of plastic material defining an internal volume of the tank 2 intended to receive the pressurized gas. The liner 4 here has a central part of generally cylindrical or tubular shape, with reference to a main axis 5 of the tank 2, and two end parts, one of which is shown in [Fig.l]. The end part of the liner 4 shown comprises a neck 6 surrounding an axial opening of the liner putting the internal volume of the tank into communication with the external environment, the neck 6 here extending towards the outside of the internal volume. The liner 4 is manufactured by injection, rotational molding or extrusion blow molding of a thermoplastic or thermoset polymer material, for example polyamide or polyethylene, and the thickness of the liner is less than or equal to 5 mm.

[0070] The tank 2 comprises a nozzle 8 at least partially formed in the neck 6 of the liner 4. The nozzle 8 has a general shape with symmetry of revolution relative to the main axis 5. The nozzle 8 comprises a central part extending partially inside the neck 6 of the liner 4 and a peripheral part extending partially around the neck 6 of the liner 4 so that the neck 6 of the liner 4 is protected from the external environment by the nozzle 8. The nozzle 8 is a metal part, for example aluminum. The nozzle 8 is configured to receive a solenoid valve 9 allowing, alternately, to fill and empty the tank of its gas.

[0071] The tank 2 comprises an annular seal 10 formed between the neck 6 of the liner 4 and the end piece 8 and housed inside a cavity of the end piece 8. The annular seal 10 is in sealed contact against the neck 6 of the liner 4 and the end piece 8 so as to produce a sealed connection between the neck 6 of the liner 4 and the end piece 8, so that the pressurized gas cannot escape from the tank 2 through a gap between the neck 6 of the liner 4 and the end piece 8. Figure 2A shows the configuration of the annular seal 10 in the tank 2 of [Fig. 1]. Figure 2B shows a configuration of the annular seal 10 according to an alternative embodiment of the invention. According to this variant, the cavity of the end piece 8 housing the annular seal 10 comprises a removable ring 12. By removing the removable ring 12, the annular seal 10 can easily be removed or placed in the cavity of the end piece 8, which makes the operation of mounting the end piece 8 on the neck 6 of the liner 4 easier..

[0072] The tank 2 comprises a reinforcing ring 14 having the function of reinforcing the neck 6 of the liner 4. The reinforcing ring 14 is integral and cannot be removed from the neck 6 of the liner 4 and, in the configuration of [Fig. 1], is arranged inside the neck 6 of the liner 4 so that the neck 6 of the liner 4 surrounds and encloses the reinforcing ring 14. In the example illustrated, the neck 6 of the liner 4 is overmolded onto the reinforcing ring 14 so that the reinforcing ring 14 is overmolded from the outside into the neck 6 of the liner 4. The reinforcing ring 14 is made of a material having a breaking stress or an elastic limit which is at least twice that of the material from which the liner 4 is made. For this purpose, the reinforcing ring 14 can be made of metal, such as aluminum or stainless steel, thermoplastic material or thermoset material.

[0073] The reinforcing ring 14 is shown in more detail in [Fig. 3]. The reinforcing ring 14 extends in the axial direction over several millimeters, of the order of 5 to 50 mm. It has on its external surface, that is to say its surface in contact with the neck 6 of the liner 4, axial grooves 16 distributed regularly over its entire length. ridge. Here, the axial grooves 16 are dimensioned so that two axial grooves are separated by a space approximately equal to twice the thickness of an axial groove. The axial grooves 16 make it possible to improve the attachment of the reinforcing ring 14 to the neck 6 of the liner 4 thanks to a shape cooperation.

[0074] The reinforcing ring 14 comprises on its external surface, that is to say its surface in contact with the neck 6 of the liner 4, radial protuberances 18 distributed regularly around its periphery and flush with an axial end of the reinforcing ring 14. The radial protuberances 18 make it possible to improve the securing of the reinforcing ring 14 to the neck 6 of the liner 4 thanks to a penetration of the radial protuberances 18 into the neck 6 of the liner 4. The radial protuberances 18 have a length less than the thickness of the liner 4 to prevent the radial protuberances 18 from risking piercing the neck 6 of the liner 4. The axial position of the radial protuberances 18 not being decisive, they could be located elsewhere than at the axial end of the reinforcing ring 14.

[0075] The reinforcing ring 14 comprises on its external surface, therefore on the same surface as that comprising the axial grooves 16, a strip 20 of uniform radius separating the axial grooves 16 into two sets of axial grooves separated by the strip 20. The annular seal 10, shown schematically, is in sealed support against a support zone of the neck 6 of the liner 4 in contact with the strip 20 of the reinforcing ring 14 integral and non-removable with the neck 6 of the liner 4 as shown in [Fig.l]. The presence of the strip 20 makes it possible to homogenize the finishing undergone by the support zone of the neck 6 of the liner 4 when the tank 2 is in service.

[0076] [Fig.4] shows reinforcing rings 14a, 14b, 14c according to alternative embodiments, the differences between which and the reinforcing ring 14 of [Fig.3] will be described.

[0077] The reinforcing ring 14a of FIG. 4A is devoid of radial protrusions. Furthermore, the strip 20 does not separate the axial grooves in the direction in which the axial grooves 16 pass through the strip 20.

[0078] The reinforcing ring 14b of Figure 4B is devoid of radial protrusions. Instead of these radial protrusions, the reinforcing ring 14b has radial notches 18' distributed regularly around its external surface. The radial notches 18' make it possible to improve the securing of the reinforcing ring 14 to the neck 6 of the liner 4 thanks to a penetration of the material of the liner 4 into the radial notches 18'. In addition, the strip 20 does not separate the axial grooves 16 in the direction where the axial grooves 16 pass through the strip 20.

[0079] The reinforcement ring 14c of Figure 4C is devoid of radial protrusions. Its outer surface has a denser set of axial grooves 16. Here, the axial grooves 16 are sized so that two axial grooves are separated by a space less than or equal to the thickness of one axial groove. Some of the grooves axial 16 extend on an axial surface of the reinforcing ring 14.

[0080] The reservoir 2 comprises means 24 for fixing the end piece 8 to the reinforcing ring 14 configured to provide mechanical anchoring of the end piece 8 to the reinforcing ring 14. This is a mechanical anchoring by screwing, but according to an alternative embodiment, it is a mechanical anchoring by snap-fastening. An axial zone of length A is defined in which the entirety of the fixing means 24 and the neck 6 of the liner 4 extend. The length A corresponds to the increase in the axial size of the tank caused by the neck 6 of the liner 4 and the fixing means 24 in the configuration where the neck 6 extends towards the outside of the internal volume of the tank 2. The length A characterizes the ratio between the useful volume of the tank 2, that is to say its internal volume, and the size of the tank 2, linked in particular to the total volume of the tank 2. By reducing the length A, the increase in the size of the tank is reduced. We observe in [Fig.l] that according to the invention, the neck 6 of the liner 4 and the fixing means 24 extend radially relative to each other. In this way, the length A is not equal to the sum of the lengths along the main axis 5 of the neck 6 of the liner 4 and the fixing means 24, but is equal to the maximum of the lengths along the main axis 5 of the neck 6 of the liner 4 and the fixing means 24. When these two lengths are equal or substantially equal, as is the case in the present embodiment, the ratio between the mechanical strength of the fixing permitted by the fixing means 24 and the size of the tank 2 is optimized. The value of the length A is preferably less than 30 mm, more preferably less than 20 mm, even more preferably less than 10 mm.

[0081] The tank 2 is manufactured by a manufacturing method comprising the following steps. The liner 4 is first manufactured, this being produced by injection molding two shells forming two halves of the liner which are then welded together. The reinforcing ring 14 is fixed in the neck 6 of the liner 4, for example by overmolding the neck 6 of the liner 4 onto the reinforcing ring 14 during the manufacture of the liner 4. The end piece 8 is then inserted at least partially into the neck 6 of the liner 4. Finally, the end piece 8 is fixed to the reinforcing ring 14 using the fixing means 24 inside the neck 6 of the liner 4 so that the reinforcing ring 14 is positioned between the neck 6 of the liner 4 and the end piece 8.

[0082] Tanks intended to contain a pressurized gas according to other embodiments of the invention will now be described. In the following, only what differentiates the tanks according to these embodiments from the tank 2 according to the first embodiment of the invention will be described. The elements of these tanks similar to those of the tank 2 according to the first embodiment of the invention bear identical numerical references.

[0083] [Fig.5] shows a reservoir 102 intended to contain a gas under pressure. according to a second embodiment of the invention. The reservoir 102 differs from that of the first embodiment in that the reinforcing ring 14 comprises a shoulder 26 for cooperation with the end piece 8 configured to receive an axial end of the end piece 8. The shoulder 26 for cooperation with the end piece 8 thus forms an axial stop making it possible to facilitate the correct positioning of the end piece 8 relative to the reinforcing ring 14. For example, when the fixing means 24 form a screw fixing, the shoulder 26 for cooperation with the end piece 8 forms a screw stop for the end piece 8 relative to the reinforcing ring 14.

[0084] [Fig. 6] shows a reservoir 202 intended to contain a pressurized gas according to a third embodiment of the invention. The reservoir 202 differs from that of the first embodiment in that the reinforcing ring 14 comprises a shoulder 28 for cooperation with the liner 4 configured to receive a complementary shoulder 30 arranged on the liner 4, at the base of the neck 6. The shoulder 28 for cooperation with the liner 4 thus forms an axial stop making it possible to facilitate the correct positioning of the neck 6 of the liner 4, and more generally of the liner 4, relative to the reinforcing ring 14. In an advantageous embodiment, the shoulder 28 includes the radial protuberances 18 or the radial notches 18'.

[0085] [Fig. 7] shows a reservoir 302 intended to contain a pressurized gas according to a fourth embodiment of the invention. The reservoir 302 differs from that of the first embodiment in that it combines the second and third embodiments of the invention. The reinforcing ring 14 comprises a shoulder 26 for cooperation with the end piece 8 configured to receive an axial end of the end piece 8, as well as a shoulder 28 for cooperation with the liner 4 configured to receive a complementary shoulder 30 provided on the liner 4, at the base of the neck 6. The operation of the shoulder 26 for cooperation with the end piece 8 and of the shoulder 28 for cooperation with the liner 4 are as described in the second and third embodiments of the invention.

[0086] [Fig.8] shows a tank 402 intended to contain a gas under pressure according to a fifth embodiment of the invention. The tank 402 differs from that of the first embodiment in that the neck 6' of the liner 4 extends towards the inside of the internal volume of the tank 2 and in that the reinforcing ring 14, integral and non-removable with the neck 6' of the liner 4, is at least partially formed around the neck 6' of the liner 4. In the example illustrated, the neck 6' of the liner 4 is overmolded onto the reinforcing ring 14 so that the reinforcing ring 14 is overmolded from the inside around the neck 6' of the liner 4. The configuration of the neck 6' of the liner 4 extending towards the inside of the internal volume of the tank 402 generates the presence of a dead volume 32 in the internal volume as described in the preamble of the present application. The fixing means 24 are located in an axial extension of the neck 6' of the liner 4 towards the internal volume of the tank, so that the neck 6' of the liner 4 is positioned between the reinforcing ring 14 and the end piece 8. The reinforcing ring 14 is located at least partially around the neck 6' of the liner 4, and it is its internal surface, that is to say the surface in contact with the neck 6' of the liner 4, which may have axial grooves, a band, radial protuberances and / or radial notches as presented in the first embodiment and in figures 3, 4A, 4B and 4C.

[0087] The tank 402 is manufactured by a manufacturing method comprising the following steps. The liner 4 is first manufactured, this being produced by injection molding two shells forming two halves of the liner which are then welded together. The reinforcing ring 14 is fixed around the neck 6' of the liner 4, for example by overmolding the neck 6' of the liner 4 onto the reinforcing ring 14 during the manufacture of the liner 4. The end piece 8 is then inserted at least partially into the neck 6' of the liner 4. Finally, the end piece 8 is fixed to the reinforcing ring 14 using the fixing means 24 located in an axial extension of the neck 6' of the liner 4 in the direction of the internal volume of the tank 402, so that the neck 6' of the liner 4 is positioned between the reinforcing ring 14 and the end piece 8.

[0088] [Fig.9] shows a reservoir 502 intended to contain a gas under pressure according to a sixth embodiment of the invention. The tank 502 differs from that of the first embodiment in that the neck 6' of the liner 4 extends towards the inside of the internal volume of the tank 2 and in that the reinforcing ring 14, integral and non-removable with the neck 6' of the liner 4, is at least partially formed around the neck 6' of the liner 4. In the example illustrated, the neck 6' of the liner 4 is overmolded onto the reinforcing ring 14 so that the reinforcing ring 14 is overmolded from the inside around the neck 6' of the liner 4. The configuration of the neck 6' of the liner 4 extending towards the inside of the internal volume of the tank 402 generates the presence of a dead volume 32 in the internal volume as described in the preamble of the present application.The fixing means 24 are located radially relative to the neck 6' of the liner 4 inside the neck 6' of the liner 4, so that the neck 6' of the liner 4 is positioned between the reinforcing ring 14 and the end piece 8. The reinforcing ring 14 is located at least partially around the neck 6' of the liner 4, and it is its internal surface, i.e. the surface in contact with the neck 6' of the liner 4, which may have axial grooves, a band, radial protuberances and / or radial notches as shown in the first embodiment and in FIGS. 3, 4A, 4B and 4C.

[0089] In the example illustrated, the reinforcing ring 14 is in fact a double reinforcing ring 14d, 14e in which a first reinforcing ring 14d is arranged outside the neck 6' of the liner 4 so that the first reinforcing ring 14d surrounds and encloses the neck 6' of the liner 4 and a second reinforcing ring 14e carries the fixing means 24. The first reinforcing ring 14d is coaxial with the second reinforcing ring 14e and its inner radius is greater than the outer radius of the second reinforcing ring 14e so that an annular space is provided between the first reinforcing ring 14d and the second reinforcing ring 14e. The first reinforcing ring 14d is connected to the second reinforcing ring 14e by a reinforcing core 15 in the form of a washer. The reinforcing core 15 has an outer radius corresponding to the outer radius of the first reinforcing ring 14d and an inner radius corresponding to the inner radius of the second reinforcing ring 14e. The annular space provided between the first reinforcing ring 14d and the second reinforcing ring 14e is provided to receive the neck 6' of the liner 4 and an axial end of the end piece 8 so that the neck 6' of the liner 4 is protected from the external environment by the end piece 8.

[0090] The tank 502 is manufactured by a manufacturing method comprising the following steps. The liner 4 is first manufactured, this being produced by injection molding two shells forming two halves of the liner which are then welded together. The reinforcing ring 14 is fixed around the neck 6' of the liner 4, for example by overmolding the neck 6' of the liner 4 onto the reinforcing ring 14 during the manufacture of the liner 4. The end piece 8 is then inserted at least partially into the neck 6' of the liner 4. Finally, the end piece 8 is fixed to the reinforcing ring 14 using the fixing means 24 located radially relative to the neck 6' of the liner 4 inside the neck 6' of the liner 4, so that the neck 6' of the liner 4 is positioned between the reinforcing ring 14 and the end piece 8.

[0091] [Fig. 10] shows a reservoir 602 intended to contain a pressurized gas according to a seventh embodiment of the invention. The tank 602 differs from that of the first embodiment in that it comprises a sealed contact surface 10' between the end piece 8 and the neck 6 of the liner 4, such that the pressurized gas cannot escape from the tank 2 through a gap between the neck 6 of the liner 4 and the end piece 8. In the illustrated example, a layer of a gas-tight material constitutes the sealed contact surface 10' between the end piece 8 and the neck 6 of the liner 4, for example, a layer of glue applied between the end piece 8 and the neck 6 of the liner 4. In another embodiment of the invention (not shown), the neck 6 of the liner 4 and the end piece 8 each have a smooth bearing surface together forming the sealed contact surface 10' between the end piece 8 and the neck 6 of the liner 4.

[0092] [Fig. 11] shows a tank 3 intended to contain a pressurized gas according to the state of the art. The tank 3 comprises a liner 104 made of plastic material defining an internal volume of the tank 3 intended to receive the pressurized gas. The liner 104 here has a central part of generally cylindrical or tubular shape, with reference to a main axis 105 of the tank 3, and two parts end portion of which one is shown in [Fig.l 1]. The end portion of the liner 104 shown comprises a neck 106 surrounding an axial opening of the liner connecting the internal volume of the tank with the external environment. The neck 106 here extends towards the outside of the internal volume of the tank 3 and has an axial offset towards the inside of the internal volume of the tank 3. The configuration of the neck 106 of the liner 3 axially offset towards the inside of the internal volume of the tank 3 generates the presence of a dead volume 132 in the internal volume as described in the preamble of the present application.

[0093] The invention is not limited to the embodiments presented and other embodiments will become clear to those skilled in the art. In particular, the embodiments of the invention relating to a tank in which the neck of the liner is oriented towards the inside of the internal volume of the tank are also applicable to a tank in which the neck of the liner is oriented towards the outside of the internal volume of the tank. And conversely, the embodiments of the invention relating to a tank in which the neck of the liner is oriented towards the outside of the internal volume of the tank are also applicable to a tank in which the neck of the liner is oriented towards the inside of the internal volume of the tank. In general, it is possible to combine the different embodiments with each other, in particular with regard to the configuration of the neck of the liner, the removable ring, the reinforcing ring and the presence of the cooperation shoulders. List of references

[0094] 2; 3; 102; 202; 302; 402; 502; 602: tank intended to contain a gas under pressure 4; 104: liner 5; 105: main axis 6; 6'; 106: neck 8: tip 9: solenoid valve 10: annular seal 10': waterproof contact surface between the tip and the neck 12: removable ring 14, 14a, 14b, 14c, 14d, 14e: reinforcement ring 15: reinforcement soul 16: axial groove 18: radial protuberance 18': radial notch 20: band 24: fixing means 26: shoulder for cooperation with the tip 28: shoulder of cooperation with the liner 30: additional shoulder 32; 132: dead volume

Claims

Claims

1. Tank (402; 502) intended to contain a pressurized gas comprising a liner (4) made of plastic material of generally cylindrical shape having a main axis (5), the liner (4) comprising a neck (6') surrounding an axial opening of the liner (4), characterized in that it comprises: - an end piece (8) at least partially formed in the neck (6') of the liner (4), - a reinforcing ring (14) of the neck of the liner integral and non-removable from the neck (6') of the liner (4), and - means (24) for fixing the end piece (8) to the reinforcing ring (14) of the neck (6') of the liner (4), characterized in that the neck (6') of the liner (4) extends towards the inside of an internal volume of the tank, in that the reinforcing ring (14) is at least partially formed around the neck (6') of the liner (4), and in that the fixing means (24) are located in an axial extension of the neck (6') of the liner (4),respectively radially relative to the neck (6') of the liner (4), in the direction of the internal volume of the tank, respectively inside the neck (6') of the liner (4), so that the neck (6') of the liner (4) is positioned between the reinforcing ring (14) and the end piece (8).,

2. Tank according to claim 1, characterized in that the neck (6') of the liner (4) is overmolded onto the reinforcing ring (14).

3. Tank (402; 502) according to any one of the preceding claims, characterized in that the reinforcing ring (14) is made of a material having a breaking stress or an elastic limit which is at least twice that of the material from which the liner (4) is made.

4. Tank (402; 502) according to the preceding claim, characterized in that the reinforcing ring (14) is made of metal, such as aluminum or stainless steel, thermoplastic material or thermosetting material.

5. Tank (402; 502) according to any one of the preceding claims, characterized in that the fixing means (24) are configured to provide mechanical anchoring of the end piece (8) to the reinforcement ring (14), for example by screwing or snapping.

6. Tank according to any one of the preceding claims, characterized in that the reinforcing ring (14) comprises a shoulder (26) for cooperation with the end piece (8) configured to receive an axial end of the end piece (8).

7. Tank according to any one of the preceding claims, characterized in that the reinforcing ring (14) comprises a shoulder (28) for cooperation with the liner (4) configured to receive a complementary shoulder (30) provided on the liner (4), at the base of the neck (6).

8. Tank (402; 502) according to any one of the preceding claims, characterized in that the end piece (8) comprises an annular seal (10) in sealed contact against the neck (6') of the liner (4), the annular seal (10) being housed in a cavity of the end piece (8), preferably the cavity of the end piece (8) is closed by a ring in order to form a groove for housing the annular seal (10), preferably the ring is a removable ring (12).

9. Tank (402; 502) according to any one of the preceding claims, characterized in that it further comprises a sealed contact surface (10') between the end piece (8) and the neck (6') of the liner (4).

10. Tank (402; 502) according to any one of the preceding claims, characterized in that the reinforcing ring (14) comprises, on its external or internal radial surface, axial grooves (16).

11. Tank (402; 502) according to the preceding claim taken in combination with claim 8, characterized in that the reinforcing ring (14) has, on the same surface as that comprising the axial grooves (16), a strip (20) of uniform radius separating the axial grooves (16) into two sets of axial grooves separated by the strip (20), and in that the annular seal (10) is in leaktight support against a support zone of the neck (6') of the liner (4) in contact with the strip (20) of the reinforcing ring (14) integral and non-removable from the neck (6') of the liner (4).

12. Method for manufacturing a tank (402; 502) intended to contain a gas under pressure, characterized in that it comprises the following steps: - manufacturing a liner (4) of generally cylindrical shape having a main axis (5), the liner (4) comprising a neck (6') surrounding an axial opening of the liner (4) and extending towards the inside of an internal volume of the tank, - fixing a reinforcing ring (14) of the neck of the liner around the neck (6') of the liner (4), - insertion of a tip (8) at least partially into the neck (6') of the liner (4), and - fixing the end piece (8) to the reinforcing ring (14) using fixing means (24) located in an axial extension of the neck of the liner, respectively radially relative to the neck (6') of the liner (4), in the direction of the internal volume of the tank, respectively inside the neck (6') of the liner (4), so that the neck (6') of the liner (4) is positioned between the reinforcing ring (14) and the end piece (8).

13. Method according to the preceding claim, characterized in that the liner (4) is made of plastic material and the step of fixing the reinforcing ring (14) of the neck of the liner to the neck (6') of the liner (4) is a step of overmolding the neck (6') of the liner (4) on the reinforcing ring (14) during the step of manufacturing the liner (4).

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