CRYOPENTER WITH PIPE PENETRATION MODULE

Description

[0001] The invention relates to a cryogenic container with a pipe penetration module comprising an inner tank and an outer container vacuum-insulated from the inner tank, wherein the pipe penetration module comprises a sheathing tube and a pipeline at least partially enclosed in the sheathing tube.

[0002] According to the state of the art, liquefied gases can be stored in containers ("cryogenic containers") for use as fuel, for example, in an engine. Liquefied gases are gases that exist in the liquid state at their boiling point, the boiling point of which is pressure-dependent. When such a cryogenic liquid is filled into a cryogenic container, a pressure corresponding to the boiling point is established, apart from thermal interactions with the cryogenic container itself.

[0003] Since the fluid stored in the cryogenic container is at a significantly lower temperature than the ambient temperature of the container, the container must be designed accordingly to minimize heat transfer. Prior art has shown that cryogenic containers can be designed as double-walled tanks, comprising an inner and an outer tank. The inner tank is enclosed within the outer tank and thermally insulated from it, for example, by maintaining a vacuum between the two.

[0004] In these embodiments, it is particularly important to consider that thermal expansion and contraction of the inner and outer tanks, which occur under different operating conditions, must be compensated for. Therefore, operational reliability is desired despite mechanical expansion and contraction and vibrations during operation.

[0005] Of particular importance here are the pipe runs between the inner and outer tanks, for example, for filling or emptying the inner tank. Due to thermal expansion and contraction, the pipe runs must be designed to allow the inner and outer tanks to slide together.

[0006] For pipe penetrations with a passage in the area of ​​the cylindrical shell of the cryogenic container, it is also possible to mount the inner tank with the already installed pipe penetrations into the outer container, i.e. the projection above the cylindrical shell of the inner tank can be chosen to be smaller than the inner diameter of the outer container, at least at the time of assembly.

[0007] US 2005 / 139600 A1 discloses a cryo container.

[0008] Therefore, one objective of the invention is to create a pipe penetration module that can accommodate thermal length changes of the inner tank and the outer container particularly well.

[0009] This objective is achieved by the cryocontainer according to claim 1.

[0010] The bend in the pipe within the casing allows for greater flexibility in the event of thermal expansion compared to linear pipe penetration modules. This effectively compensates for thermal expansion of both the inner and outer tanks. Furthermore, the bend allows the pipe to be extended further out of the casing, for example, by at least the thickness of the outer tank wall, thus simplifying the welding process to the outer tank.

[0011] The bend in the outer casing and the pipeline allows for better damping of vibrations from the outer tank, preventing them from being transmitted to the inner tank. Furthermore, connecting the outer casing to the inner tank and the pipeline to the outer tank is simple and can be achieved, for example, with an automated welding process.

[0012] A further advantage of the solution according to the invention is that no reinforcement of the inner tank is required, thus enabling small diameters of the connecting pieces, which allows the cryogenic container to be manufactured in compliance with the relevant guidelines. Finally, the bend results in a flexible design of the compensating module, thereby compensating for all individual, component, and assembly tolerances that occur during assembly.

[0013] It is advantageous if the bends are designed such that a first section of the sheathing tube or pipeline lies at an angle of 30° to 150°, preferably 70° to 110°, and particularly preferably 90°, to a second section of the sheathing tube or pipeline. While a bend of 90° is preferred, as this significantly simplifies the construction of the compensating module, other bend angles are also possible to achieve the advantages described above.

[0014] According to the invention, the pipeline or sheathing tube is more flexible over at least one functional section than outside of the functional section. This allows for improved compensation of thermal expansion and contraction through a favorable distribution of mechanical stresses. If the functional section is located on the pipeline, it is preferably situated at least partially within the sheathing tube. This can be achieved particularly by the following embodiments.

[0015] According to one embodiment, it is preferred that the pipeline has a thinner wall thickness over at least one functional section than outside the functional section, wherein the functional section is located at least partially within the outer casing. Alternatively, the pipeline can be designed as a bellows pipe over at least one functional section, wherein the functional section is located at least partially within the outer casing. Depending on the embodiment, the functional section can also be located completely within the outer casing.

[0016] Both of the aforementioned designs have the advantage that, by thinning the pipe wall thickness or by using a bellows-type pipe, a further improved compensation of thermal expansion and contraction is achieved through a favorable distribution of mechanical stresses. Furthermore, these measures prevent the concentration of increased mechanical stresses at the pipe ends where the outer casing connects to the inner tank (both at the first end of the casing and, if applicable, at the second end) and where the pipe connects to the outer tank.

[0017] In further embodiments, the casing tube may also have a thinner wall thickness over at least one functional section than outside the functional section, or the casing tube may be designed as a bellows tube over at least one functional section. In these embodiments, it is particularly preferred if the functional section is spanned by an axial stiffener. For example, two stiffening rods running parallel to the casing tube and located on opposite sides of the casing tube can be used as axial stiffeners. This allows, on the one hand, radial buckling or bending of the casing tube between the stiffening rods and, on the other hand, prevents compression of the casing tube in the axial direction.

[0018] To facilitate the installation of the pipe penetration module on the cryogenic tank, the pipeline can be provided with a weld socket at its first end for connection to the outer tank, and / or the casing pipe can have a stiffening ring at its first end for connection to the inner tank. This allows the individual components to be joined, particularly with automated welding, as the weld socket and stiffening ring are especially suitable for this purpose.

[0019] Furthermore, it is preferred if the outer casing has an end plate at its second end for connection to the inner tank. This allows the outer casing to be advantageously connected to the inner tank at its second end as well, thus enabling a rigid connection of the outer casing to the inner tank at both ends. This is intended to make it more difficult for vibrations of the pipeline to cause the outer casing to resonate.

[0020] In another embodiment, the pipeline can be equipped with an internal thread at its first end. This makes it easier to pull the pipeline end out of the pipe penetration module, thereby facilitating a welding connection to the outer container.

[0021] In its assembled state, the invention therefore relates to a cryogenic container comprising an inner tank, an outer tank vacuum-insulated from the inner tank, and a pipe penetration module according to one of the aforementioned embodiments, wherein the outer tube projects into the inner tank. The pipe projects into the inner tank on one side, but also out of the inner tank on the other, where it is connected to the outer tank.

[0022] In a particularly preferred embodiment, the pipe feedthrough module is connected to the cryogenic container in such a way that, in an operating position of the cryogenic container, the pipe feedthrough module acts as a thermal siphon. According to the invention, the bend thus not only compensates for thermal expansion changes but also prevents thermal bridges between the inner and outer tanks through the siphon effect. This is achieved because the evaporation of the liquid phase at the warm end of the pipe creates a gas cushion that cannot flow back into the inner tank, thus preventing any further flow of liquid phase. The heat input can therefore be reduced to an acceptable level. The specific installation position of the pipe feedthrough module to achieve the thermal siphon effect is at the discretion of the person skilled in the art.

[0023] Advantageous and non-restrictive embodiments of the invention are explained in more detail below with reference to the drawings. Figure 1 shows a cryogenic container with three pipe penetration modules according to the invention. Figure 2 shows one of the pipe penetration modules from Figure 1 in detail. Figure 3a shows a cryogenic container with a thermal siphon according to the state of the art and Figure 3b shows a detail of the Figure 3a . Figure 4 shows an alternative embodiment of the pipe penetration module of Figure 2 .

[0024] Figure 1Figure 1 shows a cryogenic container 1 comprising an inner tank 2 and an outer tank 3 that is vacuum-insulated from the inner tank 2. The fluid 4 stored in the cryogenic container 1 is, for example, liquefied natural gas, also known to those skilled in the art as LNG ("Liquid Natural Gas"). In the illustrated example, the fluid 4 is in liquid form up to a fill level F, and in a gaseous state above that level. The cryogenic container 1 is typically carried on a motor vehicle, in which case the fluid 4 serves as fuel for the vehicle's engine.

[0025] To introduce or remove fluid 4 from cryogenic container 1, a pipeline 5 is provided between inner tank 2 and outer tank 3. However, a rigid connection of the pipeline 5 to both the inner tank 2 and the outer tank 3 would result in thermal expansion of the inner tank 2 relative to the outer tank 3 severely affecting this connection. For this reason, the pipeline 5, together with a sheathing tube 6, is designed as a pipe penetration module 7, which is described in detail below.

[0026] According to Figure 1Three pipe penetration modules 7 are provided in the cryogenic container 1. The pipe penetration module 7 located at the top in the installation position is used as a filling line, and the two pipe penetration modules 7 located at the bottom in the installation position are used as liquid extraction lines. However, the pipe penetration module 7 is not limited to these embodiments, but can also be used, for example, as a heat exchanger inlet or outlet.

[0027] The pipe penetration module 7 is formed by the fact that the pipe 5 is at least partially enclosed in the sheathing tube 6. The sheathing tube 6 projects completely into the inner tank 2 and is rigidly connected to the inner tank 2 at a first sheathing tube end 8, for example by welding. As in Figure 2As shown, the outer casing 6 has a stiffening ring 9 at its first end 8, which facilitates welding the outer casing 6 to the inner tank 2. The stiffening ring 9 can also be formed by a thickening of the outer casing 6, thus eliminating the need for a separate stiffening ring 9.

[0028] Out of Figure 1 It is further evident that the pipeline 5 is rigidly connected to the outer tank 3 at a first pipeline end 10, e.g., welded. As in Figure 2As shown, the pipeline 5 has a welding socket 11 at its first end 10, which facilitates welding the pipeline 5 to the outer tank 3. Preferably, the first end 10 of the pipeline can also be equipped with an internal thread to make it easier to pull it out of the casing 6 for welding to the outer tank 3. Part of the pipeline 5 runs between the outer tank 3 and the inner tank 2, and the remaining part extends into the inner tank 2, where it is contained within the casing 6.

[0029] The pipe 5 has a second pipe end 12 inside the inner tank 2, and the casing pipe 6 has a second casing pipe end 13. The pipe 5 and the casing pipe 6 are rigidly connected to each other at the second casing pipe end 13, for which purpose the casing pipe 6 may have an end plate 14 in this area. The second pipe end 12 can either open into the end plate 14 or outside of it if the pipe 5 passes through the end plate 14.

[0030] Pipe 5 and casing 6 are spaced apart within the pipe penetration module 7, creating a space 15 between them. This space 15, like the space 16 between inner tank 2 and outer tank 3, is vacuum-sealed to provide thermal insulation. Space 15 is connected to the aforementioned space 16. Alternatively, the casing 6 could include a plate at its first end, which is sealed off from pipe 5, thus isolating space 15 from space 16.

[0031] According to the invention, the pipeline 5 and the casing 6 each have a kink 17, 18 in a region between the first and second casing ends 8, 13. The pipeline 5 can thus have a first section 19, the kink 17, and a second section 20, and the casing 6 can have a first section 21, the kink 18, and a second section 22. The first section 19 of the pipeline 5, which has the welded socket 11 and is connected to the outer container 3, and the first section 21 of the casing 6, which has the stiffening ring 9 and is connected to the inner tank 2, are arranged essentially coaxially. This includes deviations that occur as a result of thermal expansion and deviations due to manufacturing tolerances, which may be caused by the pipe penetration itself or by the container, the inner tank suspension, pressure vessel ends, etc.The second section 20 of the pipeline 5 and the second section 22 of the sheathing tube 6, which are connected to each other, are also arranged essentially coaxially, apart from deviations that occur due to thermal length changes and manufacturing tolerances.

[0032] The bend 17 of the pipe 5 can, for example, be achieved by a bent section of the pipe 5, so that the pipe 5 can still be manufactured in one piece. Alternatively, the first section 19, the bend 17, and the second section 20 of the pipe 5 could be manufactured separately and joined together, e.g., welded. Both of these embodiments can also be used for the first section 21, the bend 18, and the second section 22 of the casing pipe 6.

[0033] The bends 17, 18 can be designed such that the first sections 19, 21 of the pipe 5 or the sheathing tube 6 lie at an angle of 30° to 150°, preferably 70° to 110°, particularly preferably 90°, to a second section 20, 22 of the pipe 5 or the sheathing tube 6. In the illustrated example of the Figure 1 and 2 The kinks 17 and 18 form an angle of 90°.

[0034] The Figure 1 and 2The figures further show that the pipeline 5 has a functional section 23 located within the casing 6. As shown, the pipeline 5 above the functional section 23 is designed as a bellows tube, in particular a metal bellows tube, which helps the pipeline 5 withstand deformation due to thermal expansion by reducing the stresses that occur. Alternatively, the pipeline 5 above the functional section 23 can have a thinner wall thickness than the wall thickness of the pipeline 5 outside the functional section 23. The thinner wall thickness can also be achieved by a wall thickness gradient. Several functional sections 23 within the casing 6, with the same or different properties, can also be provided. The bellows tube, the metal bellows tube, or...The thin wall thickness can also be provided with a braided weave, so that the absorption capacity of the pipe 5 for high internal pressures can be improved.

[0035] Figure 3a This shows how a thermal siphon is designed according to the state of the art. In the space 16 between the inner tank 2 and the outer container 3 of a cryogenic container 1, a pipe 24 with a rise 25 of height h is provided. If fluid flows through this pipe and then the valve 26 is closed, the fluid is initially in a liquid state throughout the entire pipe 24. As shown in Figure 3bAs shown, due to the increased temperature at the outer container 3 compared to the fluid, a gas bubble 27 forms in the pipeline 24, which is held in place by the elevation 25 near the outer container 3. In combination with the elevation 25, the gas bubble 27 prevents the liquid phase 28 from flowing towards the outer container 3, thus contributing to the thermal insulation of the fluid 4 from the outer container 3. This prevents a continuous flow and evaporation of the liquid phase and the associated heat input into the inner tank.

[0036] The pipe penetration module 7 simultaneously achieves a thermal siphon for improved thermal length change, without requiring a complicated construction as in the prior art with a specially provided elevation 25 in the space 16.

[0037] According to the invention, the pipe penetration module 7 with its existing bend 17, 18 is installed in the cryogenic container 1 such that, in an operating position of the cryogenic container 1, the pipe penetration module 7 acts as a thermal siphon. This can be achieved, for example, by having the first pipe section 19 connected to the outer container 6 have a negative slope relative to the horizontal, starting from its connection point with the outer container 3. Alternatively, the first pipe section 19 connected to the outer container 6 can have a positive slope relative to the horizontal, starting from its connection point with the outer container 3, so that the bend 17 is located above the connection point of the pipe 5 with the outer container 6. In this case, however, the second pipe end 12 should open below the connection point of the pipe 5 with the outer container 6.The axis of pipe 5 does not have to lie in a normal plane of the container, but can also run at an angle to it.

[0038] Alternatively, the pipe penetration module 7 could also be installed in a different position, for example, if the pipe penetration module protrudes completely or partially above a nominal fill level F. In principle, a qualified professional can easily determine a suitable installation position for the pipe penetration module 7 so that it functions as a thermal siphon.

[0039] Thus, by suitable positioning, one and the same pipe penetration module 7 can be attached to the entire circumference of the inner container regardless of the purpose of the pipe penetration module 7, whereby the pipe penetration module 7 can be used as a thermal siphon in each case.

[0040] Figure 4 shows an alternative embodiment of the pipe penetration module 7 of Figure 2, where the same reference numerals denote the same elements. In this embodiment, the pipe 5 does not have a functional section 23, but the casing 6 has a functional section 29. This functional section 29 can also be designed as a bellows tube, as shown. Alternatively, the casing 6 could have a thinner wall thickness over the functional section 29 than outside the casing 6. In both embodiments, the casing 6 can have an axial stiffener 30 spanning the functional section 29. For example, two stiffening bars running parallel to the casing 6, located on opposite sides of the casing 6, can be used for this purpose. The stiffening bars can, for example, be welded on one side to the end plate 14 and on the other side to an intermediate plate 31, which in turn is attached to the rigid part of the casing 6.The stiffening element 30 shall be designed in such a way that it prevents the sheathing tube 6 from being compressed in the axial direction and allows bending or buckling in the radial direction.

[0041] Regardless of whether the functional section 23, 29 is located on the pipe 5 or on the casing 6, the pipe 5 or the casing 6 is designed to be more flexible over the functional section 23, 29 than outside of the functional section 23, 29. As already explained, this can be achieved, for example, by using a bellows tube or a thinner wall thickness. Due to the flexibility of the functional section 23, 29, the pipe penetration module 7 can more easily absorb bending stresses.

[0042] Depending on the embodiment, the pipeline 5 or the casing 6 can have one or more functional sections 23, 29. Furthermore, both the pipeline 5 and the casing 6 can have one or more functional sections 23, 29.

Claims

1. Cryogenic container (1) comprising an inner tank (2), an outer container (3) vacuum-insulated relative to the inner tank (2), and a pipe penetration module (7) for the cryogenic container (1), the pipe penetration module (7) comprising a cladding pipe (6) and a pipeline (5) at least partially accommodated in the cladding pipe (6), wherein the pipeline (5) passes through a first cladding pipe end (8) of the cladding pipe (6) wherein a first pipeline end (10) of the pipeline (5) can be rigidly connected, preferably welded, to the outer container (3) and the first cladding pipe end (8) can be rigidly connected, preferably welded, to the inner tank (2), wherein the cladding pipe (6) protrudes into the inner tank (2), wherein the pipeline (5) and the cladding pipe (6) are rigidly connected to one another at a second cladding pipe end (13), and wherein the pipeline (5) and the cladding pipe (6) each have a kink (17, 18) in an area between the first cladding pipe end (8) and the second cladding pipe end (13), wherein the pipeline (5) or the cladding pipe (6) is more flexible across at least one functional section (23, 29) than outside of the functional section (23, 29) dadurch gekennzeichnet, dass the functional section (23, 29) lies between the kink (17, 18) and the second cladding pipe end (13).

2. Cryogenic container (1) according to claim 1, wherein the kinks (17, 18) are configured in such a way that a first section (19, 21) of the pipeline (5) or, respectively, the cladding pipe (6) is at an angle of 30° to 150°, preferably of 70° to 110°, particularly preferably of 90°, relative to a second section (20, 22) of the pipeline (5) or, respectively, the cladding pipe (6).

3. Cryogenic container (1) according to any one of claims 1 to 2, wherein the pipeline (5) has a thinner wall thickness across at least one functional section (23) than outside of the functional section (23) or wherein the pipeline (5) is designed as a bellows pipe across at least one functional section (23), with the functional section (23) being located at least partially within the cladding pipe (6).

4. Cryogenic container (1) according to any one of claims 1 to 3, wherein the cladding pipe (6) has a thinner wall thickness across at least one functional section (29) than outside of the functional section (29) or wherein the cladding pipe (6) is designed as a bellows pipe across at least one functional section (29).

5. Cryogenic container (1) according to claim 4, wherein an axial reinforcement (30) is spanned across the functional section (29), the axial reinforcement preferably being formed by two stiffening rods running in parallel to the cladding pipe (6) and located on opposite sides of the cladding pipe (6).

6. Cryogenic container (1) according to any one of claims 1 to 5, wherein the pipeline (5) has a welding sleeve (11) at the first pipeline end (10) for connection to the outer container (3).

7. Cryogenic container (1) according to any one of claims 1 to 6, wherein the cladding pipe (6) has a stiffening ring (9) at the first cladding pipe end (8) for connection to the inner tank (2) and the stiffening ring (9) preferably is formed by a thickening of the cladding pipe (6).

8. Cryogenic container (1) according to any one of claims 1 to 7, wherein the cladding pipe (6) has an end plate (14) at the second cladding pipe end (13) for connection to the inner tank (2).

9. Cryogenic container (1) according to any one of claims 1 to 8, wherein the pipeline (5) is equipped with an internal thread at the first pipeline end (10).

10. Cryogenic container (1) according to any one of claims 1 to 9, wherein the intermediate space (15) between the pipeline (5) and the cladding pipe (6) is configured such that the first pipeline end (10) can be moved into the cladding pipe (6) by at least one wall thickness of the outer container (3) for an assembly process.

11. Cryogenic container (1) according to claim 10, wherein the pipe penetration module (7) is connected to the cryogenic container (1) in such a way that the pipe penetration module (7) functions as a thermal siphon when the cryogenic container (1) is in an operating position.

12. Cryogenic container according to claim 10 or 11, wherein the pipe penetration module (7) is passed through a jacket of the cryogenic container.