CRYOT TANK DEVICE

Description

Field of the invention

[0001] The present invention relates to a cryotank device comprising an inner container for holding a medium, in particular hydrogen, and an outer container. State of the art

[0002] Cryotank devices are known per se and are used for storing cryogenic liquids, in particular liquid hydrogen. This medium can be used, in particular, as fuel for a moving or flying means of transport, for example, a motor vehicle, aircraft, or space rocket. Cryotank devices typically comprise an inner container, i.e., an inner tank, in which the medium stored in the tank, i.e., in particular, the hydrogen, is accommodated, and an outer container surrounding the inner container. A vacuum is typically created between the inner container and the outer container to reduce heat transfer from the outside to the inside. Such cryotank devices are typically cylindrical.

[0003] From EP 2 981 756 B1 a container arrangement is known comprising an outer container and an inner container mounted in the outer container for thermal insulation, wherein an annular installation space is defined between the inner container and the outer container, wherein a single fixed bearing is provided which transmits forces acting spatially in all directions and which has rod-shaped fixed bearing securing elements which act on the one hand on the outer container and on the other hand on the inner container and can be subjected to tensile and compressive stress, wherein the rod-shaped stationary bearing securing elements are firmly connected to both the inner container and the outer container.

[0004] DE 10 2008 054090 A1 discloses a container for receiving and storing liquids and viscous substances, in particular cryogenic fluids, having an inner shell for receiving and storing the liquids and viscous substances, an outer shell which completely surrounds the inner shell, and an intermediate space which is delimited by the inner shell and the outer shell, wherein the inner shell is deformably received by the outer shell and is movable relative to the outer shell, and wherein the intermediate space between the inner shell and the outer shell is designed to be thermally insulating or to reduce heat flow, wherein the inner shell is suspended in the outer shell via struts arranged in the intermediate space between the inner shell and the outer shell, which transmit mechanical forces and / or moments.wherein the struts are each connectable at one end to the inner shell and at the other end to the outer shell.,

[0005] WO 2022 / 012867 A1 discloses a known cryogenic tank device.

[0006] Cryogenic tank systems currently on the market can use a polar suspension to attach the inner tank to the outer vessel. This means that the attachment axis of the polar suspension passes through the pole points of the vessel bottoms – at the axial ends of the cylindrical vessels. The connection between the outer vessel bottoms and the inner tank is usually made by tubular components. This is also referred to as a central tube suspension.

[0007] For LNG tanks, there are solutions where the suspension elements are made of stainless steel. This is hardly feasible for hydrogen tanks due to the relatively high thermal conductivity of stainless steel and the stringent thermal performance requirements. Therefore, composite fiber pipes are typically used, which, while similar in strength to stainless steel pipes, have lower stiffness.

[0008] Due to the increasing requirements for the maximum permissible working pressure for hydrogen tanks, the required wall thicknesses for the inner tank are also increasing. This increases, among other things, the mass and the rotational mass moment of inertia of the inner tank. Especially in mobile cryogenic tanks with central tube suspension, this can lead to a resonance between the natural frequency of the inner tank and the excitation frequency of the vehicle during operation, which can lead to damage to the suspension. Summary of the invention

[0009] It is an object of the invention to improve a cryotank device of the type mentioned in this respect and in particular to provide a cryotank device in which damage to the suspension due to the natural vibration behavior of the cryotank device is reduced.

[0010] The problem is solved by a cryotank device having the features according to claim 1.

[0011] The cryotank device comprises an inner container for holding a medium, in particular hydrogen, and an outer container, wherein the inner container and the outer container have a substantially cylindrical shape, wherein a polar suspension is arranged between the inner container and the outer container, wherein at least one rod-shaped tangential support element is arranged between the inner container and the outer container, so that the tangential support element extends substantially in the circumferential direction of the inner and outer containers from a connection on the inner container to a connection on the outer container, wherein the tangential support element is designed to be movable at least in one dimension normal to its rod-shaped extension.

[0012] According to the invention, a cryotank device thus has at least one, but preferably several tangential support elements which are arranged between an inner container and an outer container of the cryotank device.

[0013] It was determined that the required natural frequency values ​​for the inner tank's rotational mode cannot be achieved due to the insufficient torsional stiffness of the polar inner tank suspension. Accordingly, the invention proposes a measure to increase the rotational natural frequency.

[0014] The inner tank suspension using a polar suspension, particularly a central tube, is very easy to manufacture, consists of relatively few inexpensive parts, and is therefore difficult to surpass from an economic perspective. To maintain this simplicity and mitigate the disadvantages of the concept, rod-shaped parts are used as tangential supports, which are designed to be movable in at least one dimension, or even in two dimensions, perpendicular to the rod-shaped extension. According to the invention, the support elements are formed from flexible elements that can only absorb tensile forces. According to the invention, such support elements are arranged in pairs, each mirror-symmetrically to a plane containing the container axis.

[0015] The tangential support element is rod-shaped, i.e., essentially long and with a small cross-section. Preferably, the tangential support element forms a straight line.

[0016] According to the invention, several tangential support elements are distributed along the circumference of the inner container and the outer container, at regular intervals.

[0017] According to the invention, two tangential support elements of a plurality of tangential support elements are arranged mirror-symmetrically with respect to a plane containing the container axis.

[0018] According to the invention, the polar suspension is formed by a central tube. The polar suspension, in particular the central tube, runs along the longitudinal center axis of the container. The central tube preferably has a fixed bearing on one side, thus being axially fixed. On the other side, the central tube preferably has a floating bearing, thus enabling compensation for axial thermal expansion.

[0019] According to the invention, the polar suspension is formed by a composite fiber tube.

[0020] It is important that as little heat as possible is transferred from the outer container to the inner tank via the support elements. Accordingly, the support elements are designed to be as long as possible, with the smallest possible cross-section, and preferably made of a material with low thermal conductivity. Alternatively or additionally, the connections, i.e., the fastenings of the support elements to the inner and / or outer container, can be designed with low thermal conductivity, particularly as separate connection elements.

[0021] Preferably, the tangential support element is attached to the inner container and / or the outer container indirectly via a thermally decoupling connection element.

[0022] The connecting element can be made of a material with poor thermal conductivity, such as a glass-fiber-reinforced polymer material. The support element can be hinged to a connecting element at one or both ends. The connection between the support element and the connecting element and / or between the connecting element and the container can be made, for example, by welding, riveting, screwing, or clamping.

[0023] Preferably, the connecting element comprises a pivot pin, and the tangential support element is pivotably mounted on the pivot pin. The support element can also be pivotable in two dimensions, for example, if the connection to a connecting element is made via a ball joint or two pivot pins.

[0024] The connecting element and / or the support element in the area of ​​the transition to the connecting element can be flexible and / or articulated.

[0025] The tangential support element can also be directly attached to the inner container and / or the outer container, for example via welding bolts.

[0026] The extension of the tangential support element between the inner container and the outer container preferably has no axial component in the direction of the container axis - in order to particularly improve the rotational natural vibration behavior - or, in another embodiment, has an axial component in the direction of the container axis - so that the requirements for the polar connection between the containers are reduced.

[0027] The tangential support element is preferably axially fastened in a non-cylindrical end region of the inner container, i.e. in a bottom region or end cap region of the container, and preferably in a cylindrical region of the outer container, i.e. in its shell, or likewise in a non-cylindrical end region of the outer container, i.e. a bottom.

[0028] The tangential support element preferably essentially forms a tangential extension of a circumference of the inner container, extending toward the outer container. This circumference of the inner container, extended by the tangential support element, can be smaller, in the bottom or end region, than the circumference of the cylindrical central part of the inner container. Brief description of the drawings

[0029] The invention is described below by way of example with reference to the drawings. Fig. 1 is a three-dimensional exploded view of a cryogenic tank device according to the invention at one axial end of the cryogenic tank device. Fig. 2 is an end view of the axial end of the cryogenic tank device according to Fig. 1 . Fig. 3 is a sectional view of the cryogenic tank device according to the invention according to section BB of Fig. 2 . Fig. 4 is a sectional view of the cryogenic tank device according to the invention according to section CC of Fig. 3 Fig. 5 is a three-dimensional detailed view of the area around a connection element of the tangential support element on the inner container. Fig. 6 is a three-dimensional detailed view of the area around a connection element of the tangential support element on the outer container. Detailed description of the invention

[0030] In the Fig. 1 and Fig. 2 is the bottom area of ​​a cryogenic tank device according to the invention as an exploded view ( Fig. 1 ) or from the front ( Fig. 2), whereby the outer container 2 is only partially visible. Figs. 3 and 4 show partial sectional views of the same cryogenic tank.

[0031] The cryogenic tank device comprises a cylindrical inner container 1 for holding liquid hydrogen, which merges into a bottom in the axial end region, and an outer container 2. A vacuum space is provided between the inner container 1 and the outer container 2.

[0032] Between the inner container 1 and the outer container 2, i.e. preferably in the vacuum space, a polar suspension 3 is arranged at each polar, i.e. axial, end of the tanks, of which a centrally located receiving opening is shown in the inner container 1.

[0033] The polar suspension 3 is formed by a central tube that is supported on one side by a fixed bearing and on the other side by a floating bearing for axial sliding. The polar suspension 3 is formed by a composite fiber tube.

[0034] A plurality of rod-shaped tangential support elements 4, in the illustrated embodiment two tangential support elements 4, are arranged between the inner container 1 and the outer container 2, i.e. in the vacuum space, so that the tangential support elements 4 are aligned substantially in the circumferential direction and essentially each form tangential extensions of a circumference of the inner container 1, which extend towards the outer container 2.

[0035] Each tangential support element 4 is designed to be movable at least in one dimension normal to its rod-shaped extension, in that each support element 4 is articulated to a connecting element 5, 6.

[0036] The tangential support elements 4 are fastened on the one hand to the inner container 1, via connecting elements 5 of the respective tangential support element 4 on the inner container, and on the other hand to the outer container 2, via respective connecting elements 6 of the tangential support element 4 on the outer container 6.

[0037] The extension of the tangential support elements 4 between the inner container 1 and the outer container 2 has no axial component in the direction of the container axis. The tangential support elements 4 are thus perpendicular to the container center axis. In another embodiment, the tangential support elements 4 can also have an axial component in the direction of the container axis, i.e., they may not be perpendicular to the container center axis.

[0038] The two tangential support elements 4 are distributed mirror-symmetrically to each other along the circumference of the inner container 1 and the outer container 2, i.e. they are located at the same axial positions.

[0039] The tangential support elements 4 are axially fastened in a non-cylindrical end region of the inner container 1, i.e. in the region of a concavely curved bottom or an end cap of the inner container 1 and in a shell region of the outer container 2.

[0040] A connection element 5 on the inner tank 1 and a connection element 6 on the outer container 2 is in Fig. 5 or Fig. 6 presented in more detail.

[0041] Each connecting element 5, 6 has a pivot pin 7, with the tangential support element 4 pivotably mounted on the pivot pin 7. Each connecting element 5, 6 is essentially designed as a thin component that extends from a base part attached to the respective container wall to the pivot pin 7, so that the connecting elements 5, 6 have low thermal conductivity.

[0042] As a result, the tangential support element 4 is indirectly attached to the inner container 1 and / or to the outer container 2, in each case via a thermally decoupling connecting element 5, 6. List of reference symbols

[0043] 1Inner container 2Outer container 3Polar suspension 4Tangential support element 5Connection element on the inner container 6Connection element on the outer container 7Pivot bolt

Claims

1. Cryotanker comprising an inner container (1) for receiving a medium, in particular hydrogen, and an outer container (2), wherein the inner container (1) and the outer container (2) have a substantially cylindrical shape, wherein a polar suspension (3) is configured between the inner container (1) and the outer container (2), wherein the polar suspension (3) comprises a composite fibre tube as the central tube, characterized in that at least one rod-shaped tangential support element (4) is configured between the inner container (1) and the outer container (2) in such a way that the tangential support element (4) substantially extends in the circumferential direction of the inner and outer container (1, 2), from an attachment to the inner container (1) to an attachment to the outer container (2), wherein the tangential support element (4) is designed in at least one dimension to be normally movably on its rod-shaped extent, wherein a plurality of tangential support elements (4) are distributed at regular spacings along the circumference of the inner container (1) and the outer container (2), wherein of a plurality of tangential support elements (4) two tangential support elements (4) are in each case disposed mirror symmetrically in relation to a respective plane containing the container axes, wherein the support elements (4) are formed by limp elements which can only absorb tensile forces.

2. Cryotanker according to Claim 1, characterized in that the tangential support element (4) is fastened indirectly, by way of a thermally decoupling attachment element (5, 6), to the inner container (1) and / or to the outer container (2).

3. Cryotanker according to at least one of the preceding claims, characterized in that the tangential support element (4) is fastened to the inner container (1) and / or to the outer container (2) by way of an attachment element (5, 6), wherein the attachment element (5, 6) comprises a swivel bolt (7) and wherein the tangential support element (4) is pivotally mounted on the swivel bolt (7).

4. Cryotanker according to at least one of the preceding claims, characterized in that the extent of the tangential support element (4) between the inner container (1) and the outer container (2) has no axial component in the direction of the container axes, or has an axial component in the direction of the container axes.

5. Cryotanker according to at least one of the preceding claims, characterized in that the tangential support element (4) is axially fastened in a non-cylindrical end region of the inner container (1), thus in an end cap or a base of the inner container (1), wherein preferably the tangential support element (4) is axially fastened in a cylindrical region of the outer container (2), thus in a jacket of the outer container (2).