DE102014000617A1 - Compressed gas containers - Google Patents

Abstract

The invention relates to a pressurized gas container (1) having a storage volume surrounded by an inner sheath (2) of plastic material and at least one outer sheath (3) of fiber-reinforced plastic, having at least one end section (4) attached to one end of the storage volume. 5) of the end portion (4) a connection sleeve (6) is arranged. The invention is characterized in that the material of the inner shell (2) is materially connected directly or via a suitable intermediate layer (9) with the material of the connecting sleeve (6).

Description

The invention relates to a compressed gas container according to the preamble of claim 1. Furthermore, the invention relates to the use of a compressed gas container according to the invention according to claim 10.

Compressed gas containers, in particular so-called type IV compressed gas containers, are known from the general state of the art. For example, they can be used in vehicles for storing hydrogen under high pressures. In the case of hydrogen in particular, nominal pressures of 700 bar are now common. Higher pressures are also conceivable. In compressed natural gas, for which such compressed gas containers are also very often used, pressures in the order of 260 bar nominal pressure are common.

The structure of such a type IV gas cylinder is known from the general state of the art. The compressed gas container consists of at least two layers, an inner shell, the so-called liner, and an outer shell. The inner shell is typically formed of a material which is very dense for the gas to be stored under high pressure, for example a single-layer or multi-layer plastic layer, if appropriate also with a metallic intermediate layer or film. The task of the inner shell is merely to seal the compressed gas tank against escape of the gas as best as possible. The high pressures of the gas in the pressurized gas container are then absorbed by the next layer, the outer shell. This outer shell is made of a fiber-reinforced plastic material and may be formed, for example, by braiding or wrapping around the inner shell. At least one, in most cases at both ends of the gas cylinder, a mostly metallic end portion is attached, which is also referred to as a boss. This boss is typically used for mounting and storage of the tank and for receiving valve devices, in particular for receiving safety valves or a so-called on-tank valve (OTV).

Of particular importance is now the tight connection of the inner shell, so the liner, to the end section. Here must be ensured by an appropriate connection for a sufficient tightness. It is known from the general state of the art to guide the inner shell around a part of the end section on the outside and then to seal it to the fiber-reinforced outer shell by winding it with fibers. This is relatively expensive and often unreliable as a result.

From the US 2012/0085727 A1 a compressed gas container is known in which the end portion is formed in two parts, namely from the actual end portion which has a bore, and a mounted in the bore connection sleeve, which can be screwed later, for example, with a valve. In the structure according to the US publication, the inner shell is sealingly clamped between the end portion and the screwed into the end portion connecting sleeve, for which in at least one of the parts, either in the end portion and / or the connecting sleeve, a groove with a corresponding seal, for example a sealing ring, is provided. Due to the merely positive connection in the area of the seal, the construction bears the risk of a possible leak, in particular in applications in which vibrations, impacts or the like can not be completely prevented, since these can potentially lead to a loosening of the sealing connection.

Another structure in the aforementioned type is also from the DE 10 2011 011 649 A1 known. In this construction is also located in the end portion of a connecting sleeve, which is connected to the inner shell, and which is sealed by a sealing ring in the region of the thread between the connecting sleeve and the end portion accordingly. In order to provide a reliable connection between the inner shell and the connecting sleeve, a very complex connection element in the form of a catching sleeve is provided, which is connected to the inner shell on the one hand and by a plug or locking connection with the connecting sleeve on the other. The structure is extremely complex and expensive to manufacture, since it comprises several complex to produce and shaped items.

The object of the present invention is now to provide an improved compressed gas container according to the preamble of claim 1, which avoids the particular disadvantages mentioned.

According to the invention this object is achieved by a compressed gas container having the features in the characterizing part of claim 1. Advantageous embodiments and further developments emerge from the subclaims dependent thereon. In claim 10, a particularly preferred use for the compressed gas container is also specified.

The pressurized gas container constructed according to the invention now provides that the material of the inner shell is connected in a material-bonded manner directly or via a suitable intermediate layer to the material of the connecting sleeve. By such a cohesive connection, such as an adhesive or welded joint, the inner shell with the Connection sleeve creates a very simple and very reliable in terms of tightness construction, in which the inner shell is connected to the connection sleeve, that a reliable seal of the storage volume is ensured in the inner shell. This construction of inner shell and cohesively attached connection sleeve then has to be joined together only with the end sections or the end section and, for example, by braiding and / or wrapping with the fiber-reinforced plastic material through the outer shell to be completed accordingly. The structure is simple, has few components, is very dense and reliable. By cohesive connection also a release of the compound, for example, by vibrations or the like can be reliably prevented.

In a further very advantageous embodiment of the compressed gas container according to the invention, it is further provided that the inner shell is connected to the facing to the interior of the storage volume end face of the connecting sleeve. Such a connection of the inner shell only with the end face of the connecting sleeve provides a structure which is extremely simple in the further assembly, since no laterally projecting beyond the inner sleeve parts occur, which may be damaged during assembly of the inner sleeve in the end portion.

According to an advantageous development of the idea, the cohesive connection is preferably formed as a welded connection.

Another very favorable embodiment of the compressed gas container according to the invention, it also provides that the connection sleeve has a directed towards the interior of the storage volume connection contour with at least two different levels. Such Anschlusskontor with at least two different levels, which can be realized for example with a frontally grooved groove, a step-shaped configuration of the front side or the like, provides a higher surface in the region of the front page available, so that a very good and reliable cohesive connection of the inner shell the front side of the connection sleeve can be realized.

In a particularly favorable and advantageous development of the compressed gas container according to the invention, it can now further be provided that the connecting sleeve is coated or overmolded with an intermediate layer at least on its end facing the interior of the storage volume, wherein the material of the inner shell is connected to the intermediate layer. Such an intermediate layer may in particular be applied to the preferably metallically formed connecting sleeve by coating or spraying. The intermediate layer can then ensure that a very good connection, for example, a very good weld, between the material of the inner shell and the intermediate layer, which in turn is correspondingly well connected to the material of the connecting sleeve, occurs. As a result, the adhesion of the inner shell to the connection sleeve can be further improved. By connecting the end face of the connection sleeve with the inner shell, the volume for the intermediate layer can be significantly reduced. This makes it possible to use very high-quality materials that are basically available on the market and specially developed for hybrid systems, ie plastic-metal composites. Because of the relatively small volume, the high cost of such materials play a minor role. However, they can significantly improve the attachment again.

In the pressurized gas container according to the invention, according to an advantageous development, it can now also be provided that the connection sleeve is glued into the bore of the end section. Such a connection sleeve glued into the bore of the end section is particularly simple and efficient in terms of assembly. By dispensing with a screwing the burden of possibly already established connection between the ferrule and the inner shell can be reduced, so that a very simple and reliable installation is possible. Preferably, the connection sleeve has a contour with a constant outer cross-section, so it can be very easily inserted into the bore.

Another very favorable embodiment of the compressed gas container according to the invention, it now further provides that the bore has a collar in the end portion on the side facing away from the storage volume. Such a construction is ideal in terms of assembly. The connection sleeve can be inserted through the bore, which is preferably already provided with adhesive, from the later interior of the compressed gas container in the direction of the exterior. The adhesive can be activated and the adhesive bond can be formed. Due to the existing in this advantageous embodiment of the invention covenant also a mechanical assurance of the connection sleeve is achieved in the end portion, as this is held by the federal government, and can not be moved by the pressure prevailing in the pressure gas container later in the direction of pressure. The structure is so extremely easy to install and yet very reliable and very cost-effective due to the easy-to-install parts and their small number.

According to an advantageous development of the compressed gas container according to the invention, it can now be provided that the connecting sleeve is made of a metallic material, in particular of steel or stainless steel. Such a connection sleeve made of steel or stainless steel is very resistant in the region of its thread, so that even with multiple screwing and unscrewing a valve device or the like, there is no danger of seizure and thus leakage or damage.

Furthermore, the use of a connecting sleeve made of steel or stainless steel allows the material of the end section, which accommodates the connecting sleeve, to be designed approximately as desired. Thus, it is conceivable according to an advantageous development to design this, as before, from aluminum. However, according to a particularly favorable and advantageous embodiment of the compressed gas container according to the invention, it may also be provided instead to use a fiber composite material for the end section. Such a fiber composite material obtains the necessary resistance to wear and seizing in the area of the thread through the connecting sleeve, and can be produced with the largest part of its volume from the light and stable fiber composite material. The construction of the compressed gas container per se is thereby much easier, which is a decisive advantage, especially when used in mobile systems such as vehicles.

As already mentioned, the compressed gas container according to the invention can be produced very simply and efficiently and is extremely reliable and safe. It is particularly suitable for applications in which correspondingly large quantities must be realized with very high demands on the safety of the compressed gas tank at the same time. Such an application may include, in particular, the storage of hydrogen or natural gas in a vehicle. The particularly preferred use of the pressurized gas container according to the invention therefore lies in the storage of hydrogen or compressed natural gas in a vehicle, for example in a fuel cell vehicle or a vehicle with an internal combustion engine, which uses the gases as fuel.

Further advantageous embodiments of the compressed gas container according to the invention will become apparent from the embodiment, which is described below with reference to the figures.

Showing:

1 a cross section through an end portion of a gas cylinder according to the invention;

2 an enlarged detail A from the illustration in 1 ;

3 a representation analogous to the enlarged detail A in a first alternative embodiment;

4 a representation analogous to the enlarged detail A in a second alternative embodiment; and

5 a representation analogous to the enlarged section A in a third alternative embodiment.

In the presentation of the 1 is a compressed gas tank, not shown in its entirety 1 to recognize in a sectional view of its one end. The compressed gas tank 1 consists essentially of an inner shell 2 , the so-called liner 2 , as well as an outer shell 3 made of fiber-reinforced plastic, for example a reinforced with carbon fibers or aramid fibers plastic. This fiber-reinforced plastic can, for example, be wound up and / or braided and then solidified by curing a plastic matrix which was either already present on the fibers or which is subsequently applied. The outer shell 3 has the task to mechanically absorb the pressure load, while the unsuitable inner shell 2 is formed of a suitable plastic material in one or more - possibly also metallic - layers, which should above all achieve a diffusion tightness against the enclosed gas, for example hydrogen. There is also an end section 4 , the so-called boss, in the depiction of 1 to recognize in cross section. This has a hole 5 in its interior, into which a connection sleeve, in this case a threaded sleeve 6 , is introduced. To prevent from the pressure inside the gas cylinder 1 the connection sleeve 6 towards the outside, in the representation of 2 So up, being moved, points the hole 5 at its upper end in the representation of the 2 a covenant 7 on which a mechanical stop for the connection sleeve 6 in the hole 5 formed. In addition, the connection sleeve 6 in the hole 5 with the material of the end section 4 glued accordingly. This is indicated by a dotted adhesive layer 11 in the enlarged view of the section A in 2 to recognize.

The material of the inner shell 2 is with the front side 8th the connection sleeve 6 welded, where in the representation of the 1 and 2 additionally an intermediate layer 9 on the front page 8th the connection sleeve 6 which is composed in such a way that on the one hand it is very dense and secure connection to the metallic material of the connection sleeve 6 and on the other hand, a good and secure weld with the material of the inner sleeve 2 guaranteed. For better adhesion of the intermediate layer 9 at the front 8th the connection sleeve 6 this is formed in several levels, in the representation of the 1 and 2 is for example a projecting middle part of the front page 8th realized. Alternatives of this connection are in the 3 - 5 to recognize, in the representation of the 3 a groove is introduced in the front side and in the representations of 4 and 5 a stepped configuration of the front side 8th is realized. All these are conceivable solutions, which will be discussed in detail later.

The in the end section 4 glued connection sleeve 6 also has, as it can be seen in the illustration of the figures, a thread 10 on, in which later corresponding connection elements, such as an on-tank valve can be screwed.

The connection sleeve 6 can be very easily and efficiently mechanically pre-machined and can be a corresponding thread 10 wear, which is useful and intended for later use. For example, different thread pitches or thread types or thread diameter can be easily and efficiently realized without having to change the entire structure. The connection sleeve 6 is then over the adhesive bond 11 into the hole 5 of the end section 4 glued and then in the embodiments according to the illustration of 1 . 2 and 4 with the intermediate layer 9 encapsulated gas-tight, with this encapsulation, in principle, before the insertion of the connection sleeve 6 in the end section 4 could be done. Subsequently, the inner shell 2 by a welding process in the embodiment of 1 . 2 and 4 to the intermediate layer 9 and in the other embodiments according to the 3 and 5 directly to the front side 8th the connecting sleeve welded. This results in a very reliable and dense construction, which finally in a conventional manner with the outer shell 3 For example, by wrapping and / or braiding with the fiber material and subsequent impregnation and curing of a plastic matrix is completed. An alternative to gluing the connection sleeve 6 can also be a pressing, especially in an embodiment of both the end portion 4 as well as the connection sleeve 6 made of metal. The connection sleeve 6 may in particular be made of a steel, such as a stainless steel. The end section 4 can be realized very easily and efficiently from aluminum. The end section 6 is then easy and efficient to produce, for example, by injection molding or forging. This is already common in today's end sections according to the prior art. However, then there is the danger that a screwed valve device can eat very easily, so that a very complex after-treatment must be done for example by anodizing. Such can be dispensed with when using a connecting sleeve, for example made of steel. The structure is thereby very simple and inexpensive to manufacture and yet can take advantage of the light metal for most of its volume.

Further, it is possible to use the end portion 4 also to produce from a non-metallic material, for example, a fiber composite material, a fiber-reinforced plastic, but in principle also of a ceramic material or the like. Such a structure is in particular by the use of the connection sleeve 6 made of a steel material, since the connection can be made in particular by gluing and so a heavy-duty thread through the use of the connection sleeve 6 in the end section 4 can be introduced.

In principle, with every construction of the end section 4 , But especially in its realization of a fiber composite material, it is also conceivable, the shape of the connection sleeve outside and the bore 5 of the end section 4 inside so that a positive connection is created. For example, a polygonal shape could be used to twist the ferrule 6 even without the glue 11 already to prevent.

In the case of the design of the end section 4 From fiber-reinforced composite material, it would also be conceivable, the connection sleeve 6 externally provided with appropriate supernatants, fins or the like, which allow an additional positive connection with the fiber composite material. In this case, the connection sleeve would 6 so practically in the production of the fiber composite material of the end portion 4 built into the end section and so firmly and securely connected to this.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2012/0085727 A1 [0005]
• DE 102011011649 A1 [0006]

Claims (10)

Compressed gas tank ( 1 ) with one of an inner shell ( 2 ) made of plastic material and at least one outer shell ( 3 ) of fiber-reinforced plastic surrounded storage volume, with at least one attached to one end of the storage volume end portion ( 4 ), whereby in a bore ( 5 ) of the end section ( 4 ) a connection sleeve ( 6 ), characterized in that the material of the inner shell ( 2 ) directly or via a suitable intermediate layer ( 9 ) with the material of the connection sleeve ( 6 ) is integrally connected. Compressed gas tank ( 1 ) according to claim 1, characterized in that the inner shell ( 2 ) with the facing to the interior of the storage volume end face of the connection sleeve ( 6 ) connected is. Compressed gas tank ( 1 ) according to claim 1 or 2, characterized in that the inner shell ( 2 ) with the connection sleeve ( 6 ) is welded. Compressed gas tank ( 1 ) according to one of claims 1, 2 or 3, characterized in that the connecting sleeve ( 6 ) has a directed in the direction of the interior of the storage volume terminal contour having at least two different levels. Compressed gas tank ( 1 ) according to one of claims 1 to 4, characterized in that the connecting sleeve ( 6 ) at least on its the inside of the storage volume facing end face ( 8th ) with an intermediate layer ( 9 ) is coated or overmolded, wherein the material of the inner shell ( 2 ) with the intermediate layer ( 9 ) is welded. Compressed gas tank ( 1 ) according to one of claims 1 to 5, characterized in that the connecting sleeve ( 6 ) into the hole ( 5 ) of the end section ( 4 ) is glued. Compressed gas tank ( 1 ) according to one of claims 1 to 6, characterized in that the connecting sleeve ( 6 ) is made of a steel material, in particular of stainless steel. Compressed gas tank ( 1 ) according to one of claims 1 to 7, characterized in that the bore ( 5 ) in the end section ( 4 ) on the side facing away from the storage volume a collar ( 7 ) having. Compressed gas tank ( 1 ) according to one of claims 1 to 8, characterized in that the end section ( 4 ) consists of a fiber composite material. Use of the compressed gas container ( 1 ) according to one of claims 1 to 9, as a storage volume for hydrogen or compressed natural gas in a vehicle.

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