Pressure Vessel and Method for Producing a Pressure Vessel

Abstract

A pressure vessel for containing pressure, for example, high pressure associated with storage of compressed gaseous fuels, includes a wall which surrounds an interior space. The wall includes an arrangement of wall threads and a matrix. An internal structure having a number of internal threads is provided for bracing, the internal threads having portions embedding in the matrix adjacent to the wall threads. A method for producing a pressure vessel of this type is also provided.

Claims

1-10. (canceled)

11. A pressure vessel, comprising a wall surrounding an interior space (8), the wall including an arrangement of wall threads embedded in a matrix; and an internal structure, the inner structure including a plurality of inner threads, wherein the plurality of inner threads enter the wall at respective entry points and are anchored in the matrix, and each of the plurality of inner threads brace at least two entry points of the wall relative to one another.

12. The pressure vessel according to claim 11, wherein each of the plurality of inner threads are anchored in the matrix by one or both of engaging around at least one of wall threads between two entry points, and running through the matrix between the at least one of the wall threads and an outer side of the wall.

13. The pressure vessel according to claim 12, wherein each respective one of the plurality of inner threads runs between two respective entry points exclusively within the matrix.

14. The pressure vessel according to claim 13, wherein the wall is configured to be one or more of flat segments, in the form of ball segments, and cylinder segments adjoining one another.

15. The pressure vessel according to claim 14, wherein at least some or all of the entry points lie at a respective boundary between one or more of two of the ball segments and two of the cylinder segments adjoining one another.

16. The pressure vessel according to claim 15, wherein wherein the plurality of inner threads one or both of run completely or partially freely in the interior space, and are not embedded in a matrix in the interior space or a liner.

17. The pressure vessel according to claim 11, wherein wherein the plurality of inner threads one or both of run completely or partially freely in the interior space, and are not embedded in a matrix in the interior space or a liner.

18. The pressure vessel according to claim 11, wherein the plurality of inner threads and the wall threads are interlaced with one another in a plain weave, in a twill weave or in an m-to-n weave.

19. The pressure vessel according to claim 11, wherein the plurality of inner threads are configured to brace the wall in one spatial direction, in two spatial directions or in three spatial directions.

20. The pressure vessel according to claim 11, wherein the plurality of inner threads are embedded partially in a matrix such that a plurality of gas-tight external chambers are formed in the interior space.

21. A method for producing a pressure vessel having a wall surrounding an interior space, the wall including an arrangement of wall threads embedded in a matrix, and an internal structure, the inner structure including a plurality of inner threads, wherein the plurality of inner threads enter the wall at respective entry points and are anchored in the matrix, and each of the plurality of inner threads brace at least two entry points of the wall relative to one another, comprising the acts of: immersing the wall threads and respective adjacent or encompassing portions of the inner threads in a bath of the matrix material; and forming concave boundary surfaces of the wall between the plurality of inner threads as the matrix rises up along the inner threads.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows a pressure vessel in accordance with an embodiment of the present invention,

[0029] FIG. 2: shows a first possible arrangement of inner threads in accordance with an embodiment of the present invention,

[0030] FIG. 3 shows a second possible arrangement of inner threads in accordance with an embodiment of the present invention,

[0031] FIG. 4: shows a third possible arrangement of inner threads in accordance with an embodiment of the present invention, and

[0032] FIG. 5: shows a possible anchoring of inner threads in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

[0033] FIG. 1 shows a pressure vessel 5 according to one exemplary embodiment. The pressure vessel 5 comprises a wall 10. The wall 10 has an outer side 12 and an inner side 14. The wall 10 encloses an interior space 8 in which pressurized gas or other substances can be stored.

[0034] The wall 10 is formed from a number of wall threads 20 and a matrix 22 in which the wall threads 20 are embedded. In the present case, the wall threads 20 are arranged in a grid-like structure which is not illustrated any further.

[0035] An internal structure 9 having a number of vertical inner threads 30 and horizontal inner threads 32 is arranged in the interior of the pressure vessel 5. In this case, the inner threads 30, 32 enter the wall 10 or the matrix 22 at respective entry points 16.

[0036] As shown, a respective inner thread 30, 32 engages in this case around a wall thread 20. In this way, the inner threads 30, 32 are interlaced with the wall threads 20, as a result of which a particularly high stability can be achieved. The inner threads 30, 32 are fundamentally anchored in the matrix 22.

[0037] As shown, entry points 16 at which the inner threads 30, 32 penetrate into the wall 10 lie opposite one another in each case in pairs. In this way, the inner threads 30, 32 can advantageously ensure stability of the pressure vessel 5, since the pulling apart of respective entry points 16 and thus also of the wall 10 can be prevented by the inner threads 30, 32. This permits a higher pressure load in the case of a constant wall thickness, or a smaller wall thickness for a particular pressure.

[0038] It has been shown that, according to an advantageous embodiment, the inner threads 30, 32 are embedded in the matrix 22 merely in the wall 10, in order to prevent slippage. For the interior space 8 which is subjected purely to tensile loading, it is otherwise possible to dispense with a matrix around the inner threads 30, 32. The inner threads 30, 32 thus lie freely in the interior space 8. For an assumed fiber volume content of 60%, for example, this saves a total of 40% of the volume of all of the inner walls, and this volume which is thus freed up is additionally available for the storage of fuel. In other words, the inner walls are reduced to tension braces.

[0039] As already mentioned, the anchoring of the inner threads 30, 32 in the wall 10 is assisted by the wall threads 20 running in the wall 10. A plurality of intersecting wall threads 20 may also be used to anchor a respective inner thread 30, 32. Conversely, it is also possible to use one wall thread 20 to anchor a respective plurality of inner threads 30, 32. In other words, all types of weaves, such as for example plain, twill or m-to-n, of woven fabrics may also be employed for the interaction between wall threads 20 and inner threads 30, 32.

[0040] FIG. 2 shows an alternative embodiment in which merely a tensile bracing by means of inner threads 30 in one dimension is present. FIG. 3 shows the embodiment which is already known from FIG. 1 and in which a bracing in two dimensions by means of inner threads 30, 32 is present. FIG. 4 shows a further alternative, wherein a bracing in three dimensions by means of inner threads 30, 32, 34 is present. Embodiments of this kind can be used in a pressure vessel 10. Other arrangements of inner threads 30, 32, 34 are also possible, however.

[0041] Spatial directions in which no bracing by means of inner threads 30, 32, 34 is present may each be embodied for example with solutions as in the design of conventional pressure tanks. As a result of the displacement of fibers or threads from the wall 10 into the interior space, it is possible for spaces which can deviate considerably from traditional solutions such as for example cylinders or balls and which can then have planar tank walls to be formed. A liner may be applied to the inner side of the outer wall. However, use may preferably also be made of a matrix material which makes the use of a liner as separate permeation barrier unnecessary. In particular, thermoplastics or thermosets may be used as matrix material for this purpose.

[0042] FIG. 5 shows an alternative embodiment of the anchoring of an inner thread 30 in the wall 10, said alternative embodiment being able to be used in a pressure vessel in combination with the embodiment shown in FIG. 1 or exclusively as an alternative. In this case, the inner thread 30 does not engage around a wall thread 20, but rather is embedded in the matrix 22 in an approximately T-shaped manner between the wall threads 20 and the outer boundary 12 of the wall 10. This also makes it possible to achieve high stability and good anchoring. The wall threads 20 would nevertheless serve as stabilization for the inner threads 30 in the case of corresponding loading.

[0043] A “half-T”, or an “L”, that is to say embedding on substantially one side, is also possible. However, three-dimensional embedding is preferred, that is to say a profile of the inner thread 30 in the matrix 22 such that the profile of the inner thread in the interior space 8 and in the matrix 22 does not lie in one plane. For example, the profile in the matrix 22 could describe a circle, an ellipse or an “8”.

[0044] The matrix for the wall 10 can be produced by different methods. For example, the subsequent wall or the wall threads 20 may be immersed in a resin bath. The force of gravity and capillary forces can in this case have the effect that the matrix material is placed around the inner threads 30, 32, 34 in such a way that variations in stiffness are avoided. Additive manufacturing methods, in particular liquid material methods, can also be used for this. The planar geometry of the tank wall makes it much easier to carry out both bath and immersion methods and liquid material methods.

[0045] Preferably, during the production of the tank wall, concave structures are also produced around the inner threads 30, 32, 34 by the matrix, specifically as viewed from the interior space. This is already shown in FIG. 1. Concave structures of this kind have a favorable effect on the strength properties, since the force acting on the outer wall is satisfactorily distributed to the inner threads 30, 32, 34.

[0046] Ideally, the pressure vessel 10 is designed such that with increasing internal pressure stretching occurs uniformly on all sides. As a result, bending forces are largely avoided.

[0047] The surface density of the inner threads 30, 32, 34 anchored in the outer wall has a direct influence on the stiffness properties of the respective surface element. By adapting the surface density of the inner threads 30, 32, 34 anchored in the wall 10, it is thus possible for the uniform stretching to be shaped or forced. In particular, this can be employed in the vicinity of edges and corners, since the wall 10 has an inherent stiffness transverse to the inner threads 30, 32, 34 due to the wall threads 20, said inherent stiffness being taken into account for the design of the pressure vessel 10.

[0048] In order to increase the vessel safety even further, it is possible to not completely dispense with a liner and matrix material for all of the internal walls or inner threads 30, 32, 34. Instead, a type of double-wall structure or generally multi-wall structure can be achieved through targeted use of matrix, and possibly also liner, for inner walls which are located near to the tank wall 10. This can be used for the diagnosis of leaks, for example. In addition, the behavior with respect to external mechanical influences, for example in the case of a crash, is improved.

[0049] Generally speaking, the inner threads 30, 32, 34 in the interior space 8 improve the burst properties, since said inner threads represent a flow obstruction for very high speeds, as would occur in the event of a tank bursting, and thus can effectively level off the pressure wave in the burst event. The wall threads 30, 32, 34 without surrounding matrix material have the effect that there is a very efficient transfer of heat with respect to the wall 10. In addition, the inner threads 30, 32, 34 represent a very large surface.

[0050] For example, a short-fiber-reinforced plastic or a metal alloy can also be used for production of the wall 10, wherein for example highly cost-effective extrusion methods can be used. Preferably, in the case of short-fiber-reinforced plastic, forming should take place in such a way that the fibers are thereby oriented in the direction of loading of the pressure tank 10. Here, too, additive manufacturing methods can be employed again. It is for example possible to use a powder bed method, preferably using a metal powder. Corresponding process control thus makes it possible to design the wall 10 to be gas-tight, for example, but to design the inner walls to be intentionally permeable to gas.

[0051] Overall, it has been shown that there is a very great improvement in the volume efficiency of the pressure vessel 10 in the embodiments under consideration. Efficient use of cuboidal or differently shaped installation spaces is made possible. Furthermore, there is very efficient heat conduction with respect to the wall 10. Burst protection and an additional degree of safety can also be achieved by means of an internal multi-wall structure.