Pressurized gas tank

Abstract

Pressurized gas tank Tank (1) for pressurized gas comprising: - a tubular component (2) having a free end (6), said free end (6) having a first thread (11) and a first sealing surface (13) and - a plug (3, 4) having a second thread (17) and a second sealing surface (16), in which, in a mounted state of the tank (1), the first thread (11) is engaged with the second thread (17) and the first sealing surface (13) is in sealing contact with interference with the second sealing surface (16), the tank (1) having in said mounted state an internal space (7) for storing pressurized gas delimited on the one hand by an internal surface (8) of the tubular component and, on the other hand, by the plug (3, 4). Abstract figure: [Fig. 1]

Description

Title of the invention: Pressurized gas reservoir Technical field

[0001] The invention relates to the field of fluid storage. More particularly, the invention relates to the field of gas storage systems, for example hydrogen or oxygen. Even more particularly, the invention relates to the field of fluid storage at pressures greater than 100 bars.

[0002] One of the technologies for reducing the carbon footprint of industries is to use hydrogen generated by the electrolysis of water. The hydrogen thus produced must be compressed and stored so that it can then be used on demand to power motor vehicles, such as trucks or cars, or to supply the electricity grid, particularly during peak consumption. In this case, to supply an electricity grid, the hydrogen can power either a turbine or hydrogen fuel cells. As for oxygen, which is the second product of water electrolysis, it may be interesting to store it for use in a field such as agriculture or for medical purposes.

[0003] Some gases, such as hydrogen, are known to be difficult to contain. Their low density requires high-pressure storage, and their small molecules and low viscosity make their storage prone to leaks. Therefore, they must be stored in a perfectly sealed storage system, while meeting strict safety standards. Technological background

[0004] Known storage devices comprise a tubular portion whose ends are forged and heat-treated to form a closed end of the tank. Such tanks require a complex manufacturing process and consume a large amount of energy. These tanks also have a significant weight which does not facilitate their movement or transport, for example on trucks.

[0005] Also known, for example from document EP3862619, are hydrogen tanks formed from a tube whose ends cooperate with a respective cap. In such tanks, the sealing at the ends of the tank is ensured by an annular seal inserted between an internal face of the tube and an external face of the corresponding cap. Such an annular seal is housed in a groove provided on the cap.

[0006] Such tanks are complex to produce and have limited resistance to internal pressure.

[0007] There is therefore a need for pressurized fluid storage tanks, particularly hydrogen, which are simple, reliable and energy-efficient to manufacture. Summary

[0008] An idea underlying the invention is to provide a tank that is simple to manufacture. An idea underlying the invention is also to provide such a tank that does not require a large amount of energy to manufacture. An idea underlying the invention is also to provide such a tank that has good pressure resistance and good sealing.

[0009] For this purpose, the invention provides a tank for pressurized gas comprising: - a tubular component having a free end, said free end having a first thread and a first sealing surface and - a cap having a second thread and a second sealing surface, in which, in a mounted state of the tank, the first thread is engaged with the second thread and the first sealing surface is in sealed contact with interference with the second sealing surface, the tank having in said mounted state an internal space for storing pressurized gas delimited on the one hand by an internal surface of the tubular component and, on the other hand, by the cap.

[0010] Such a tank is simple to manufacture. Indeed, in such a tank the seal is ensured simply by screwing the cap onto the free end of the tubular component. Furthermore, this seal is directly obtained by the interference between the first sealing surface and the second sealing surface which are directly formed respectively on the free end of the tubular component and the cap. Thus, it is not necessary to obtain this seal for an added part such as an O-ring or other seal nor for a complex and energy-consuming forging step.

[0011] Furthermore, the first sealing surface and the second sealing surface ensure good reliability of the tank, both due to the interference and by their integration directly on the free end of the tubular component and, respectively, the cap.

[0012] Furthermore, the cap of such a reservoir can be easily removed, thus allowing access to the interior of the tubular component for checking and maintenance operations of the interior of the tubular component. Such a cap can also be easily replaced or even reused on another tubular component in the event of malfunction of said cap or the tubular component respectively.

[0013] Similarly, in the event of degradation of the free end of the tubular component, for example degradation of the first thread, it is possible to simply cut said degraded free end and to produce a new thread directly on the tubular component thus cut to allow said tubular component to be reused. in the tank, without requiring a forging step or other complex and expensive additional processing.

[0014] According to embodiments, such a pressurized gas reservoir may comprise one or more of the following characteristics, alone or in combination.

[0015] Preferably, the first thread and the first sealing surface are formed on the same surface of the tubular component. Similarly, the second thread and the second sealing surface are formed on the same surface of the plug. In other words, the first thread and the first sealing surface are both formed on the inner surface or on the outer surface of the tubular component. Similarly, the second thread and the second sealing surface are both formed, respectively, on the inner surface or the outer surface of the plug.

[0016] Preferably, the tubular component comprises a main body and a connector, said connector forming the free end of the tubular component.

[0017] Preferably, the internal and / or external diameter of the main body is constant.

[0018] Preferably, the end forms an opening of the tubular component. This opening is preferably substantially equal to the internal diameter of the main body. Typically the opening has an area of between + / - 10% of the area of a cross-section of the main body.

[0019] Preferably, the first thread is a male thread and the second thread is a female thread. That is, the first thread is formed on an outer surface of the tubular component and the second thread is formed on an inner surface of the cap.

[0020] Preferably, the first thread is interposed, in an axial direction of the tubular component, between the first sealing surface and the main body of the tubular component.

[0021] According to one embodiment, the cap comprises a tubular portion and a bottom. The tubular portion forms the second thread and the second sealing surface.

[0022] Preferably, the bottom develops in a plane perpendicular to a longitudinal axis of the tubular portion.

[0023] In the assembled state of the tank, the longitudinal axis of the tubular component and the longitudinal axis of the tubular portion of the cap are coaxial.

[0024] Preferably, the second sealing surface is interposed between the second thread and the bottom of the cap.

[0025] In one variant, the first thread is a female thread and the second thread is a male thread. Thus, in this variant, the first thread is formed on an inner surface of the tubular component and the second thread is formed on an outer surface of the cap.

[0026] In a variant, the first sealing surface is interposed between the first thread and the main body of the tubular component while the second thread is interposed between the second sealing surface and the bottom of the plug.

[0027] According to one embodiment, one of the free end of the tubular component and the plug comprises a lip, one of the first sealing surface and the second sealing surface being formed on said lip.

[0028] Preferably, this lip forms on its external surface said one of the first sealing surface and the second sealing surface. In other words, the lip is formed on a male portion of the connection between the tubular component and the plug.

[0029] According to one embodiment, the first thread is inclined relative to the longitudinal axis of the tubular component. Similarly, the second thread is inclined relative to the longitudinal axis of the tubular portion of the plug. Preferably, the angle of inclination of the first thread relative to the longitudinal axis of the tubular component is, in absolute value, identical to the angle of inclination of the second thread relative to the longitudinal axis of the tubular portion of the plug.

[0030] Preferably, the lip has a thickness less than the thickness of the main body of the tubular component.

[0031] The stresses undergone by the tank being mainly internal pressure stresses linked to the thrust of the stored pressurized gas, an idea at the basis of the invention is to optimize the connection between the plug and the tubular component as a function of this internal pressure.

[0032] Furthermore, in the loaded state, i.e. with pressurized gas stored in said tank, the total weight of the tank is mainly determined by the weight of the tubular component and the cap, the weight of the stored pressurized gas representing only a small percentage of the total weight of the tank, of the order of a few percent. Thus, an optimization of the weight of the tank as such makes it possible, for an equivalent total weight of the loaded tank, to store more pressurized gas.

[0033] Thus, one embodiment provides for optimizing the thickness of the lip and / or the critical section of the thread formed on the element carrying this lip to the internal pressure of the tank in order to limit the connection to the needs of such a storage tank.

[0034] Indeed, the use in the state of a connector such as those used in oil exploitation wells intended to withstand stresses of very varied natures such as internal pressures, external pressures, tensile and compressive stresses etc., would generate an excess weight which would be detrimental both from the point of view of the quantity of available storage and of handling of the reservoir. In addition, such connectors would require unnecessarily complex manufacturing and installation.

[0035] Thus, according to one embodiment, a thickness of the lip is a function of the target pressure of the tank. Preferably, such a target pressure corresponds to the maximum internal pressure that the tank can withstand under the effect of stored pressurized gas without degradation of the tank and / or gas leakage. According to an alternative embodiment, this target pressure is a proof test pressure, typically a pressure defined to validate the resistance of a tank before its operation. According to an alternative embodiment, this target pressure is the service pressure of the tank, i.e. the internal pressure used or recommended for the use of the tank.

[0036] Similarly, according to one embodiment, a critical section of the thread formed on the element carrying the lip is a function of the target pressure of the reservoir.

[0037] Thus, according to a preferred embodiment, a thickness of the lip at right angles to the sealing surface formed on said lip, typically said one of the first sealing surface and the second sealing surface, is such that: [Math 1] nr v Pstorase-LJD with DL being the thickness of the lip at the right of said one among UL. SZX 2ys-Pstorage the first sealing surface and the second sealing surface; Pstorage being a target pressure of the tank, LID being an internal diameter of the lip, and Ys being an elastic limit of the lip.

[0038] Thanks to these characteristics, the lip has a limited thickness, thus reducing the weight of the element carrying said lip and therefore of the tank. In addition, a lip whose thickness at the right of the bearing surface meets the above equation leaves sufficient thickness of material to produce the thread on the element comprising the lip, i.e. the free end of the tubular component or the cap. Indeed, a lip with a greater thickness would not allow for a thread with satisfactory taper and tensile strength.

[0039] Ideally, the thickness of the lip at the right of the sealing surface formed on said lip, typically said one of the first sealing surface and the second sealing surface, is such that: [Math 2] nr <- i ç v PstoraseP^ This allows to optimize the maximum thickness of the lip and LfL. 1.3 X ZYs-Pstorage therefore the weight of the tank while leaving enough thickness to position the thread on the element containing the lip.

[0040] According to a preferred embodiment, the thickness of the lip at right angles to said one of the first sealing surface and the second sealing surface is such that [Math 3] 0.46 x PstorageLID 2.Ys-Pstorage <DL

[0041] Thanks to these characteristics, the thickness of the lip at the bearing surface is sufficient to ensure the sealing of the tank in a reliable and satisfactory manner. In particular, a lip having a thickness at the bearing surface that is thinner than according to the above inequality would be too fragile and not rigid enough to ensure the sealing of the tank against the internal pressure in a reliable and satisfactory manner.

[0042] Ideally, the thickness of the lip at the right of said one among the first sealing surface and the second sealing surface is such that [Math 4] „ PstorageLID 0.66 X 2.Ys-Pstorage —

[0043] Thus, the minimum thickness of the lip is optimized so as to guarantee the sealing of the tank under the internal pressure of the gas stored in the tank.

[0044] Preferably, the thickness of the lip at right angles to said one of the first sealing surface and the second sealing surface is such that [Math 5] PstorageLID PstorageLID 0.46 X 2 ys-Pstorage — 2.Ys-Pstorage

[0045] A reservoir such as above having a lip meeting this inequality is optimized to present a limited weight while ensuring the watertightness of the tank reliable and satisfactory manner.

[0046] Ideally, the thickness of the lip at the right of said one among the first surface sealing and the second sealing surface is such that [Math 6] PstorageLID 0.66 X 2.Ys-Pstorage <DL< 1.5 x PstorageLID 2Y s-Pstorage

[0047] A lip having a thickness at the right of the span meeting this inequality is thus optimized so as to have minimal weight but sufficient reliability to guarantee the sealing of the tank.

[0048] Similarly to the thickness of the lip, it is important to optimize the thickness of the thread of the element comprising the lip and, ideally, of both threads. Thus, a critical thread section of the lip-carrying element must have a thickness that is both sufficient to ensure that said thread withstands the internal pressure of the gas contained in the tank and thin enough not to unnecessarily increase the weight of the tank.

[0049] Such a critical section is defined at the bottom of the first engaging tooth of the thread, i.e. at the bottom of the engaging tooth closest to the main body of the tubular component or the bottom of the plug depending on the thread considered. Indeed, this first engaging tooth constitutes a zone of the thread in which the stresses

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] undergone by said thread under the effect of the internal pressure of the tank are the most important. It is therefore important that the critical section is large enough to guarantee sufficient resistance to pressures and traction induced by internal pressure but also optimized so that the tank remains as light as possible. Preferably, the surface area generated by thread loading flanks is greater than or equal to the critical section of the thread. Usually, thread loading flanks are understood to mean the flanks of the teeth facing the main body or the bottom of the plug depending on the thread considered, as opposed to the guide flanks which are the flanks of the teeth facing the free end of the corresponding thread. Thus, said one of the free end of the tubular component and the plug comprising the lip has a critical thread section such that [Math 7] < PCCS Wherein PCCS is the critical section of said one of the first thread and the second thread having said critical thread section, Aint is an internal sectional area of the tubular component, and DLnom is a nominal thickness of the lip at said one of the first sealing surface and the second sealing surface. Nominal thickness means the theoretical thickness, corresponding to the connection specifications and as used for example to parameterize the machining, it being understood that, due to manufacturing tolerances linked for example to the machining and precision of the machines used, the actual value can generally vary from this nominal value. Such a critical section has sufficient thickness to guarantee the mechanical resistance and tightness of the tank. Preferably, said one of the free end of the tubular component and the plug comprising the lip has a critical thread section such that [Math 8] PCCS < In which DLmax is a maximum lip thickness at the right of said one among the first sealing surface and the second sealing surface, that is to say the maximum actual thickness. A critical section satisfying this inequality has a thickness adapted to the internal pressure of the tank, the tank thus having a limited thickness at the thread level and therefore being light. So, ideally, the critical section of the thread is such that [Math 9] 2AintDLnom < nf-pc < 2.Amt.DLmax (LID+DIjwm) ~ ~ (LID+DLmax)

[0058] A tank having a thread whose critical section meets this inequality is therefore optimized to present satisfactory resistance to internal pressure while being light.

[0059] Preferably the tubular component is made of metal. Similarly, the cap is preferably made of metal. Such a metal is for example carbon steel, preferably martensitic, 13 Chromium steel, anti-corrosion steel or stainless steel.

[0060] The tank can store any type of gas under pressure, such as hydrogen, oxygen, nitrogen, methane or other.

[0061] According to one embodiment, the reservoir comprises a plurality of tubular components connected to each other, at least one free end of the reservoir being formed by one of said tubular components, the cap as above cooperating with said free end so as to close the reservoir in a leaktight manner.

[0062] According to one embodiment, the cap comprises a valve. Preferably, this valve is arranged on the bottom of the cap. This valve allows, in a closed state, the blocking of gas in the tank or, in an open state, the passage of gas through the cap to allow the filling or extraction of gas to or from the internal space of the tank.

[0063] According to one embodiment, the valve is removable, the main body of the cap comprising a through-orifice in which the valve can be mounted. Typically, this through-orifice opens out on either side of the bottom of the cap. The valve can be mounted in the orifice of the main body by any means, for example by cooperation between an internal thread of the through-orifice and an external thread of the valve, by force-fitting, by clipping or any other means allowing the valve to be mounted on the main body in a sealed manner while allowing or not the passage of gas through the valve into or from the inside of the tank depending on the activation state of the valve.

[0064] According to one embodiment, the free end of the tubular component is a first free end, the plug being a first plug, the tubular component further comprising a second free end, said second free end forming a third thread and a third sealing surface, the reservoir further comprising a second plug, said second plug comprising a fourth thread and a fourth sealing surface, the third thread being engaged with the fourth thread and the third sealing surface being in sealing contact with interference with the fourth sealing surface in the assembled state of the reservoir, the pressurized gas storage space being delimited by the internal space of the tubular component, the first plug and the second plug.

[0065] Preferably, the second plug and the second free end have characteristics similar to the first plug and the first free end respectively as described above.

[0066] In the context of a tank comprising a plurality of tubular components, the second free end is formed by a free end of the tubular component furthest from the first tubular component.

[0067] According to one embodiment, a second end of the tubular component opposite the first free end is closed. This closure can be obtained by any other means or type of treatment making it possible to ensure the sealing of the reservoir, it being understood that this closure is ideally carried out in a manner analogous to the cooperation between the free end and the cap as described above. Brief description of the figures

[0068] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the appended drawings. 1. [Fig. 1] is a longitudinal sectional view of a tank comprising a tubular component, both ends of which are closed by a cap according to one embodiment of the invention; 2. [Fig.2] is a schematic detail view of the connection between the tubular component and the plug of [Fig.l]. 3. [Fig.3] is a schematic perspective view of a plug of [Fig.l]. 4. [Fig.4] is a sectional view of the cap of [Fig.3]. Definition(s)#:

[0069] The following terms are defined within the scope of the invention:

[0070] Thread: Set of threads of a part, male or female, generated by a geometric profile moving along a surface following a helical movement.

[0071] The stabbing flanks are the thread surfaces capable of coming into contact when the threads of the male and female threaded components are engaged into each other. They therefore correspond to the flanks directed towards the free end of the tubular component in question.

[0072] Loading flanks are the thread surfaces capable of coming into contact when a threaded joint is subjected to axial tensile forces. They therefore correspond to the flanks directed on the side opposite the free end of the tubular component in question.

[0073] The term "crest" means the projecting part where the two flanks of a thread meet. In other words, within a threaded portion, a "crest" corresponds to the junction between the top of a load flank and the top of an engagement flank of the same tooth. The term "crest" of a flank means the portion of the flank that is the furthest radially from the longitudinal axis of the thread.

[0074] In a sectional representation, the term "tooth" means a notched portion extending from the base of an engagement flank to the base of a load flank, said engagement flank and said load flank being joined by a crest.

[0075] The term "root" of a thread means the junction between the base of a supporting flank of a first tooth and the base of an engaging flank of a second tooth, the first tooth and the second tooth being successive. The term "base" of a flank means the portion of the flank being radially closest to the longitudinal axis of the thread.

[0076] Sealing interference is understood to mean the difference between the value of the average diameter of the portion carrying the sealing surface before force-fitting and the value of the average diameter of the portion carrying the sealing surface once it is force-fitted and cooperating with another sealing surface.

[0077] In the description, figures and claims, the X axis corresponds to the axis of revolution of a tubular component. By convention, the "radial" orientation is directed orthogonally to the X axis and the "axial" orientation is directed parallel to the X axis.

[0078] The terms "external" and "internal" are used to define the relative position of an element, with reference to the X axis. An element close to the X axis is thus qualified as internal or radially internal as opposed to an element qualified as external or radially external located radially on the periphery.

[0079] The terms "proximal" and "distal" are used to define the relative position of an element along the X-axis. An element close to one end of the tubular component along the X-axis is thus termed distal as opposed to an element termed proximal located closer to the center of the tubular component along the X-axis.

[0080] Lip means the portion of the tubular component located between, on the one hand, a distal end of said tubular component and, on the other hand, the thread of said tubular component.

[0081] A joint formed of two connections may comprise a male sealing surface and a corresponding female sealing surface which, when contacted, constitute a metal / metal seal. Description of the embodiments

[0082] [Fig.l] illustrates a tank 1 comprising a tubular component 2, a first cap 3 and a second cap 4.

[0083] The tubular component 2 has a main body 5 and two open free ends 6 located on either side of said main body 5. The main body 5 is substantially cylindrical and defines a longitudinal axis X of the tank 1. Such a tubular component 2 is for example between 1 and 13 meters in length.

[0084] In [Fig.l], each free end 6 is closed by a respective plug 3 or 4 so that the reservoir 1 has an internal space 7 delimited by an internal surface 8 of the tubular component 2 and the plugs 3 and 4.

[0085] In the embodiment illustrated in [Fig.l], the first plug 3 comprises a central orifice 9. This central orifice 9 is intended to receive a valve (not shown) making it possible to connect the internal space 7 and a source of pressurized gas or, on the contrary, to release pressurized gas contained in the tank 1 via said valve. Such a plug 3 comprising this central orifice 9 is described in more detail below with reference to FIGS. 3 and 4.

[0086] [Fig.2] illustrates in detail the cooperation between one of the free ends 6 of the tubular component 2 and the first plug 3.

[0087] The free end 6 comprises successively from the main body 5 a first thread 11 and a lip 12. This lip 12 comprises a first sealing surface 13. The first thread 11 and the first sealing surface 13 are formed on an external surface of the tubular component 2. Typically, the free end 6 forms a male type connector.

[0088] As illustrated in more detail in Figures 3 and 4, the first cap 3 comprises a tubular portion 14 and a bottom 15. This tubular portion 14 forms a female-type connector, i.e. formed on an internal surface of said tubular portion 14. This female connector successively comprises, from the bottom 15, a second sealing surface 16 and a second thread 17. In the assembled state of the tank 1 as illustrated in Figures 1 and 2, the tubular portion has a longitudinal axis X' coaxial with the longitudinal axis X of the tubular component 2.

[0089] The first thread 11 is inclined relative to the axis X. Similarly, the second thread 17 is inclined relative to the axis X'. The first thread 11 and the second thread 17 are complementary to allow the screwing of the cap 3 onto the free end 6.

[0090] In the assembled state of the tank 1, the first thread 11 is engaged with the second thread 17 and the first sealing surface 13 is in sealed interference contact with the second sealing surface 16. This interference contact ensures the sealing of the tank 1 at the junction between the cap 3 and the free end 6.

[0091] The plug 3 and the tubular component 2 are preferably made of metal. The seal between the plug 3 and the tubular component 2 is thus ensured by a metal / metal contact with interference between the first sealing surface 13 and the second sealing surface 16.

[0092] In order to limit the weight of the tank, the characteristics of the connection between the plug 3 and the free end 6 are defined as a function of a target storage pressure of the tank. Indeed, in such a tank, the main constraint on said connection is linked to the pressure resulting from the pressurized gas stored in said tank 1.

[0093] Thus, a thickness 18 of the lip 12 at the right of the first sealing surface 13 is determined so as to ensure the reliability of the sealing of the tank 1 while by limiting its impact on the weight of the tank 1. For this, this thickness 18 is determined so as to satisfy the following inequality: [Math 10] 0.46 X PstorageLID * PstorageLID 2.Ys-Pstorage — — 2 X 2.Ys-Pstorage

[0094] In which: Pstorage is the target pressure of tank 1, LID is an internal diameter 19 of lip 12, Ys is the elastic limit of lip 12, and DL is the thickness 18 of the lip 12 at the right of the first sealing surface 13.

[0095] Preferably, the thickness 18 is determined so as to satisfy the following inequality: [Math 11] PstorageLID PstorageLID ^•06 X ^Ÿs-Pstorage S DL < 1.5

[0096] In a similar manner to the lip 12, a critical section 20 of the first thread 11, taken at the level of the bottom of the tooth of the first thread 11 closest to the main body 5 of the tubular component 2, is determined so as to allow good conicity of said first thread 11 and ensure good mechanical resistance to the internal pressures of the tank 1 while limiting the impact of said first thread 11 on the weight of the tank 1. For this, the critical section 20 satisfies the following inequality: [Math 12] < PCCK < in which PCCS is the critical section 20 of the (LID+DLnom) ~ ~ (LID+DLmax) first thread 1, Aint is an internal area of the section of the tubular component, DLnom is a nominal thickness, i.e. defined by the manufacturing specifications, of the lip 12 at the right of the first sealing surface 11, LID is an internal diameter 19 of the lip 12, and Dlmax is the maximum thickness of the lip 12 at the first sealing surface 11, typically the maximum measured thickness of the lip 12 at the first sealing surface 11.

[0097] Furthermore, the surface area generated by the loading flanks of the threads of the first thread 11 is greater than or equal to the critical section 20 (PCCS).

[0098] Figures 3 and 4 illustrate in more detail the cap 3 of [Fig.l] and show in particular the central orifice 9. This central orifice 9 passes through the bottom 15. Thus, as illustrated in [Fig.l], in the assembled state of the tank 1, the central orifice 9 opens onto an internal face 22 of the bottom 15 in the internal space 8 of the tank 1. Furthermore, the central orifice 9 also opens onto an external face 23 of the bottom 15. This central orifice 9 has an internal thread located on the side of the external face 23 to receive a valve (not shown). Such a valve allows the filling of the tank 1 or the extraction of pressurized gas from the tank 1 depending on the open or closed state of the valve. The sealing of such a valve can be obtained by any means, for example by pressing one end of the valve on a narrowing 24 in the central orifice 9.

[0099] The pressurized gas stored in the tank 1 can be of different types. This gas is, for example, hydrogen, oxygen, methane, natural gas, biogas, nitrogen or other.

[0100] The thickness of the lip 12 and of the critical section 20 of the first thread being optimized as a function of the target pressure of the tank 1, this tank 1 has a limited weight. Thus, this tank makes it possible to store more gas under pressure for the same amount of gas for the same weight as a tank not having these optimizations or to weigh less than a tank not having these optimizations and storing an identical quantity of gas under pressure.

[0101] In the embodiments illustrated in Figures 1 to 4, the tubular component 2 forms a male connector and the plugs 3 or 4 form female connectors. However, the optimization described above applies identically in the case of a male connector formed on a plug and a female connector formed on the tubular component.

[0102] Furthermore, a single tubular component 2 is illustrated in [Fig.l]. However, such a tubular component 2 could be formed from a plurality of tubular components joined end to end in a sealed manner and jointly forming a large tubular component 2 whose free ends 6 would be closed by respective plugs 3 and 4.

Claims

Claims

1. A tank (1) for pressurized gas comprising: - a tubular component (2) having a free end (6), said free end (6) having a first thread (11) and a first sealing surface (13) and - a cap (3, 4) having a second thread (17) and a second sealing surface (16), wherein, in a mounted state of the tank (1), the first thread (11) is engaged with the second thread (17) and the first sealing surface (13) is in sealing contact with interference with the second sealing surface (16), the tank (1) having in said mounted state an internal space (7) for storing pressurized gas delimited on the one hand by an internal surface (8) of the tubular component and, on the other hand, by the cap (3, 4).

2. A pressurized gas tank (1) according to claim 1, wherein one of the free end (6) of the tubular component (2) and the cap (3, 4) comprises a lip (12), one of the first sealing surface (13) and the second sealing surface (16) being formed on said lip (12).

3. A pressurized gas tank (1) according to claim 2, wherein a thickness (18) of the lip (12) at the right of said one of the first sealing surface (13) and the second sealing surface (16) is such that: nr <' 1 v PstorageL1D with DL being the thickness (18) of the lip (12) UL. LX 2.Ys-Pstorage at the right of said one of the first sealing surface (13) and the second sealing surface (16); Pstorage being a target pressure of the tank (1), LID being an internal diameter (19) of the lip (12), and Ys being an elastic limit of the lip (12).

4. A pressurized gas tank (1) according to claim 2, wherein a thickness (18) of the lip (12) at right angles to said one of the first sealing surface (13) and the second sealing surface (16) is such that: n 4r v PstorageLlD with dl being the thickness (18) of the lip U.4O X 2.Ys-Pstorage - (12) at right angles to said one of the first sealing surface (13) and the second sealing surface (16); Pstorage being a target pressure of the tank (1), LID being an internal diameter of the lip (12), and Ys being an elastic limit of the lip (12).

5. A pressurized gas tank (1) according to claim 3 or 4, wherein the thickness (18) of the lip (12) at right angles to said one of the first sealing surface (13) and the second sealing surface (16) is such that: n PstorageLID - PstorageUD 0.46 X 2Ys~Pstorage ~ ZYs-Pstorage

6. A pressurized gas tank (1) according to one of claims 2 to 5, wherein said one of the free end (6) of the tubular component (2) and the cap (3, 4) comprising the lip (12) has a critical thread section (20) such that < PCCS with PCCS being the critical section (20) (LlD+DLnom) — v 7 of said one of the first thread (13) and the second thread (17) having said critical thread section (20), Aint being an internal section of the tubular component and DLnom being a nominal thickness of the lip (12) at right angles to said one of the first sealing surface (13) and the second sealing surface (16).

7. A pressurized gas tank (1) according to one of claims 2 to 5, wherein said one of the free end (6) of the tubular component (2) and the cap (3, 4) comprising the lip (12) has a critical thread section (20) such that PCCS < >■ with PCCS being the critical section (20) of one of the first thread (11) and the second thread (17) having said critical thread section (20), Aint being an internal section of the tubular component and DLmax being a maximum thickness of the lip (12) at right angles to said one of the first sealing surface (13) and the second sealing surface (16).

8. A pressurized gas tank according to claim 6 or 7, wherein said critical thread section (20) is such that ZAintDLiwm < pÇ'Ç'Q < ZAintDLmax (LID+DLnom) — (LID+DLmax)

9. Pressurized gas tank according to one of claims 1 to 8, in which the cap (3) further comprises a through orifice (9), a valve being mounted in this orifice (9).

10. Pressurized gas tank according to one of claims 1 to 9, wherein the free end (6) of the tubular component (2) is a first free end, the plug (3) being a first plug, the tubular component (2) further comprising a second free end, said second free end forming a third thread and a third sealing surface, the tank (1) further comprising a second plug, said second plug comprising a fourth thread and a fourth sealing surface, the third thread being engaged with the fourth thread and the third sealing surface being in sealing contact with interference with the fourth sealing surface in the mounted state of the tank (1), the internal space (7) for storing pressurized gas being delimited by the internal surface (8) of the tubular component (2), the first plug and the second plug.

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