Transport containers and methods

Abstract

The present invention relates to a transport vessel (1) for helium (He), the transport vessel (1) comprising an inner vessel (6) for receiving helium (He), an insulating element (26) provided on the outside of the inner vessel (6), a refrigerant vessel (14) for receiving a cryogenic liquid (N2), an outer vessel (2) in which the inner vessel (6) and the refrigerant vessel (14) are received, and a heat shield (21) that can be actively cooled using the cryogenic liquid (N2) and in which the inner vessel (6) is received, a peripheral gap (31) being provided between the insulating element (26) and the heat shield (21), the insulating element (26) comprising an electrodeposited copper layer (27) facing the heat shield (21).

Description

Technical Field

[0001] The present invention relates to a transport container for helium and a method for manufacturing such a transport container.

[0002] Helium is extracted together with natural gas. The transport of large quantities of helium is only possible in liquid or supercritical form, i.e., only under temperatures of about 4.2 to 10 K and pressures of 1 to 13 bar. To transport liquid or supercritical helium, a transport container insulated in a complex process is used to prevent an excessive rapid increase in the pressure of the helium. Such a transport container can be cooled, for example, using liquid nitrogen. In this case, a heat shield cooled with liquid nitrogen is provided. The heat shield shields the inner container of the transport container. Liquid or cryogenic helium is accommodated in the inner container. The retention time of the liquid or cryogenic helium in such a transport container is about 45 days, which means that after this time, the pressure in the inner container increases to a maximum value of 13 bar. The insulation of the transport container consists of high-vacuum multilayer insulation.

[0003] WO 2017 / 190848 A1 describes such a transport container for liquid helium. This transport container comprises an inner container for receiving helium, an insulating element provided outside the inner container, a refrigerant container for receiving cryogenic liquid, an outer container in which the inner container and the refrigerant container are received, and a heat shield that can be actively cooled using cryogenic liquid and in which the inner container is received. In this case, a peripheral gap is provided between the insulating element and the heat shield, and the insulating element has a copper coating facing the heat shield. The copper coating is in the form of rolled copper foil here.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Under these circumstances, the object of the present invention is to provide an improved transport container.

[0005] Therefore, a transport container for helium is proposed. The transport container comprises an inner container for receiving helium, an insulating element provided on the outside of the inner container, a refrigerant container for receiving cryogenic fluid, an outer container that receives the inner container and the refrigerant container, and a heat shield that can be actively cooled using the cryogenic fluid and that receives the inner container, with a peripheral gap provided between the insulating element and the heat shield, and the insulating element having an electrodeposited copper coating facing the heat shield.

[0006] Because a peripheral gap is provided between the insulating element and the thermal shield, the insulating element does not mechanically contact the thermal shield. As a result, heat can be transferred from the surface of the inner vessel to the thermal shield only by radiation and residual gas conduction. By providing the thermal shield, it is ensured that the inner vessel is surrounded only by surfaces having a temperature corresponding to the boiling point of the cryogenic fluid (boiling point of nitrogen at 1.3 bara: 79.5 K). As a result, there is only a small temperature difference between the thermal shield (79.5 K) and the inner vessel (temperature of helium at 1 bara to 13 bara: 4.2 to 10 K) compared to the surroundings of the outer vessel.

[0007] It has been found that by using an electrodeposited copper coating instead of rolled copper foil, the total heat generation rate can be reduced from approximately 6W (rolled copper foil) to 3.5W (electrodeposited copper coating). As a result, the holding time of liquid helium can be significantly extended from 45 days to 85 days compared to the transport containers mentioned in the introduction. This simplifies transport, allows for longer transport distances, and reduces transport costs.

[0008] The inner container may also be called a helium container or inner tank. The transport container may also be called a helium transport container. Helium may be called liquid or cryogenic helium. Helium is, in particular, a cryogenic fluid. Transport containers are designed to transport helium in particular in cryogenic or liquid form, or in supercritical form. In thermodynamics, the critical point is a thermodynamic state of a substance characterized by the equalization of densities of the liquid and gas phases. At this critical point, there is no difference between the two states of the substance. In a phase diagram, the critical point represents the upper end of the vapor pressure curve. Helium is introduced into the inner container in liquid or cryogenic form. Then, a liquid region with liquid helium and a gaseous region with gaseous helium are formed within the inner container. Thus, after being introduced into the inner container, helium has two phases, different states of the substance, namely the liquid state and the gaseous state. This means that a phase boundary between liquid helium and gaseous helium exists within the inner container. After a certain period of time, that is, as the pressure inside the inner vessel increases, the helium inside the inner vessel becomes single-phase. Subsequently, the phase boundary no longer exists, and the helium is supercritical.

[0009] The cryogenic fluid or cryogen is preferably liquid nitrogen. The cryogenic fluid may also be referred to as a refrigerant. The cryogenic fluid may also be, for example, liquid hydrogen or liquid oxygen. It should be understood that a heat shield is “actively coolable” or “actively cooled,” in particular, that a cryogenic fluid flows at least partially through or around the heat shield to cool it. For this purpose, the heat shield may be provided with a cooling line or several cooling lines containing the cryogenic fluid. The cryogenic fluid boils in the process. Thus, both a gaseous and a liquid phase of the cryogenic fluid exists. Therefore, the cryogenic fluid can be contained in the cooling line in both gaseous and liquid phases. In contrast to “active cooling,” in the case of “passive cooling,” the heat shield is cooled primarily by heat conduction alone. Cryogenic fluid can also be used for passive cooling. However, in this case, the fluid does not flow around or through the heat shield, but the heat shield is in partial contact with the cryogenic fluid, for example. Areas of the heat shield that do not come into direct contact with the cryogenic fluid are cooled by heat conduction.

[0010] In particular, the heat shield is actively cooled only under one operating condition, namely when the inner container is filled with helium. When the cryogenic fluid is consumed, the heat shield does not need to be cooled. When the heat shield is actively cooled, the cryogenic fluid may boil and vaporize. Therefore, the heat shield has a temperature that is approximately or exactly the same as the boiling point of the cryogenic fluid.

[0011] The heat shield is positioned particularly inside the outer container. The refrigerant container is positioned particularly outside the heat shield. The inner container is preferably positioned outside the refrigerant container. Conversely, the refrigerant container is also positioned outside the inner container, and both the refrigerant container and the inner container are positioned inside the outer container. The refrigerant container is particularly preferably positioned next to and away from the inner container.

[0012] On the outside, the inner container, particularly the insulating element, preferably has a temperature that is approximately or exactly the same as the temperature of the helium. The heat shield may have a tubular base and a cover portion that closes the base at the front and is positioned between the inner container and the coolant container. The cover portion preferably completely closes the base at the front. The base of the heat shield may have a circular or substantially circular cross-section. The outer container, inner container, coolant container, and heat shield may have a rotationally symmetric design with respect to a common axis of symmetry or central axis. The inner and outer containers are preferably made of stainless steel. The inner container preferably has a tubular base that is closed on both sides by a curved cover portion. The inner container is fluid-sealed. The outer container also preferably has a tubular base that is closed on both sides at the front by a cover portion. The base of the inner container and / or the base of the outer container may have a circular or substantially circular cross-section.

[0013] The intermediate space between the inner and outer containers is preferably left empty. The inner container is surrounded by insulating elements to reduce the rate of heat generation in the non-vacuum state, so that in the event of vacuum collapse, the helium contained within the inner container can be released through a safety valve provided on the inner container. As a result, the insulating elements have an emergency heat insulation function in the event of vacuum collapse.

[0014] The insulating element is preferably multilayered. The insulating element may also be called a multilayer insulating element. The term "multilayered" means, in particular, that the insulating element has several overlapping coatings or layers, for example, alternating coatings of aluminum foil and glass paper, where the outermost coating or layer is an electrodeposited copper coating. Here, the "outermost" layer or coating refers to the coating of the insulating element furthest from the inner container. In this case, the outermost coating is closest to and faces the heat shield. An intermediate space is provided between the inner container and the heat shield where the insulating element is placed. This intermediate space is filled with the insulating element up to the periphery. For example, the insulating element is wound on the inner container.

[0015] The term "electrodeposition" of copper coating should be understood to mean that the copper coating is deposited onto a support, such as a metal drum, from a copper solution, particularly a solution containing copper ions. Thus, in contrast to rolled copper foil, the copper coating is constructed at the atomic level from a copper solution. The copper coating has a bare metal surface; that is, the copper coating is not surface-coated or oxidized. As the emissivity of the copper coating decreases with decreasing temperature, heat transfer by radiation also decreases, and therefore the total heat generation rate to the inner container can be reduced to approximately 3.5 W over the entire helium holding time.

[0016] The copper coating preferably has a thickness of at least 5 μm, particularly preferably at least 10 μm, preferably less than 20 μm, and particularly preferably in the range of 10 to 20 μm. The copper coating preferably has a copper mass fraction of at least 99% copper, particularly preferably at least 99.9% copper. The copper coating preferably has a surface that is free of impurities such as fats or oils.

[0017] According to one embodiment, the peripheral gap has a gap width of 5 to 15 mm, preferably 10 mm.

[0018] The presence of a gap around the periphery should be understood as meaning that the gap extends completely around the periphery of the inner container. In particular, the gap is also provided in the cover portion of the inner container.

[0019] In a further embodiment, the peripheral gap is left empty.

[0020] This ensures that heat can be transferred from the inner container to the heat shield only by radiation and residual gas conduction.

[0021] In a further embodiment, the copper coating has a wall thickness of 10 μm to 20 μm.

[0022] The wall thickness can also be referred to as the thickness. Copper can be saved with a small wall thickness. For this reason, the manufacturing cost is reduced. However, the copper coating may also be less than 10 μm or more than 20 μm thick.

[0023] According to a further embodiment, the insulating element is fixed to the outside of the inner container.

[0024] For example, the insulating element can be wound around the inner container. The insulating element can be fixedly connected to the inner container, for example, adhered.

[0025] According to a further embodiment, the insulating element is a multi-layer insulation disposed between the inner container and the copper coating. fate have.

[0026] The insulating element can be a so-called MLI (multi-layer insulator). The copper coating is preferably an additional layer of smooth copper foil made of high purity bare copper, MLI and is applied exactly without wrinkles.

[0027] According to a further embodiment, the multi-layer insulation The connection is has several layers in which layers of aluminum foil and layers of glassine paper are alternately arranged.

[0028] The layers of aluminum foil are used as reflectors and as mechanical connections for the layers of glassine paper to ensure insulation in case of vacuum breakdown. The aluminum foil can be perforated and embossed.

[0029] According to a further embodiment, the layers of aluminum foil and the layers of glassine paper are applied to the inner container without gaps.

[0030] "Without gaps" should be understood in particular to mean that the layers of aluminum foil are placed flat against the layers of glassine paper. Multi-layer insulation FateWhen applied to the inner container, care is taken to ensure the greatest possible mechanical pressure on the aluminum foil layer and the glass paper layer in order to keep all layers as isothermal as possible. An isothermal phase change is a thermodynamic phase change in which the temperature remains constant.

[0031] In a further embodiment, the copper coating is copper foil.

[0032] In particular, the copper coating is a foil of high-purity bare copper, and multi-layer insulation edge It is applied perfectly and without wrinkles. Here, "foil" should be understood to mean a flat component of a thin wall that is flexibly deformable due to its thin wall thickness, i.e., the aforementioned 10 μm to 20 μm.

[0033] In a further embodiment, the copper coating has a surface facing away from the tank and facing the heat shield, and a surface facing the tank and facing away from the heat shield, for manufacturing-related reasons.

[0034] As described above, the copper coating is deposited onto a carrier immersed in a tank filled with a copper solution. The carrier may be a cylindrical drum or roller. The surface or side facing away from the tank supports the carrier and can be referred to as the surface or side facing the carrier, or the surface or side facing the drum. Depending on the surface quality of the carrier, which can be highly polished, a very low roughness results on the surface facing away from the tank compared to, for example, the side facing the tank. The surface or side facing the tank does not support the carrier and can be referred to as the surface or side facing away from the carrier, or the surface or side facing away from the drum. The surface facing away from the tank can be referred to as a smooth surface, while the surface facing the tank can be referred to as a rough surface of the copper coating. The high roughness of the surface facing the tank results from the electrodeposition process.

[0035] According to a further embodiment, the transport container is a multilayer insulation placed between the heat shield and the outer container. fate Prepare further.

[0036] Absolute The connection is Preferably, it is the same as MLI. The insulating coating preferably completely fills the intermediate space provided between the heat shield and the outer container, and therefore, Insulation It comes into contact with both the heat shield and the outer container.

[0037] According to further embodiments, multilayer insulation The connection is It has several layers in which layers of aluminum foil and layers of glass silk, glass mesh cloth, or glass paper are arranged alternately.

[0038] A layer of glass paper, glass silk, or glass mesh cloth acts as a spacer between the layers of aluminum foil and acts as a reflector. The aluminum foil is preferably perforated and embossed. As a result, an insulating layer is placed between the heat shield and the outer container. The connection is It can be emptied without any problems. Undesirable mechanical thermal contact between aluminum foil layers is also reduced. This contact can interfere with the temperature gradient established by radiative exchange between the aluminum foil layers.

[0039] In a further embodiment, a layer of aluminum foil and a layer of glass silk, glass mesh cloth, or glass paper are applied to the heat shield with gaps between them.

[0040] "Having a gap" should be understood to mean, in particular, that an intermediate space that can be left empty is provided in each case between the layer of aluminum foil and the layer of glass silk, glass mesh cloth, or glass paper. In contrast to the insulating element of the inner container, edge The aluminum foil layer and the glass silk, glass mesh cloth, or glass paper layer are preferably loosely introduced into the intermediate space provided between the heat shield and the outer container. Here, "loosely" means that the aluminum foil layer and the glass paper layer are not compressed, and as a result, the embossing and perforation of the aluminum foil prevents insulation. edge, Therefore, the intermediate space can be left empty without any problems.

[0041] In a further embodiment, the outer container is emptied.

[0042] As a result, heat transfer is possible solely through radiation and residual gas conduction, ensuring excellent thermal insulation.

[0043] According to a further embodiment, the heat shield completely surrounds the inner container.

[0044] The heat shield is preferably made of aluminum. In particular, the heat shield is made of high-purity aluminum. As a result, particularly good heat transport and heat reflection properties are obtained. The heat shield, which completely encloses the inner container, ensures that the inner container is completely surrounded by a surface having a temperature corresponding to the boiling point of the cryogenic fluid.

[0045] According to a further embodiment, the heat shield has a base and two cover portions that close the base on both front sides.

[0046] The two cover portions are preferably curved. In particular, the cover portions are mounted on the base so as to curve away from the base. One of the cover portions is preferably positioned between the refrigerant container and the inner container. This ensures that even if the liquid level in the refrigerant container drops, the inner container is surrounded only by surfaces having a temperature corresponding to the boiling point of the cryogenic fluid.

[0047] According to further embodiments, the heat shield is fluid-permeable.

[0048] This means the heat shield is permeable to liquids and gases. For this purpose, the heat shield may have, for example, openings, holes, or pores. Fluid permeability allows for the emptiness of the intermediate space between the inner container and the heat shield.

[0049] In a further embodiment, the central axis of the transport container is oriented parallel to the horizontal line.

[0050] The horizontal line is oriented, in particular, perpendicular to the direction of gravity. The transport container is designed to be substantially rotationally symmetric with respect to its central axis. This means that when the transport container is being transported, it is transported "on its side".

[0051] Furthermore, a method for manufacturing the above-mentioned helium transport container is proposed. This method includes a) a step of providing an inner container for receiving helium; b) a step of manufacturing an electrodeposited copper coating; and c) a step of applying an insulating element to the outside of the inner container, wherein the insulating element has a copper coating as the outermost layer relative to the inner container.

[0052] The method may further include the steps of providing and / or manufacturing a refrigerant container for receiving a cryogenic fluid; providing and / or manufacturing an inner container and an outer container in which the refrigerant container is received; and providing and / or manufacturing a thermal shield in which the inner container is received, which can be actively cooled using the cryogenic fluid. In this case, a peripheral gap is provided between the insulating element and the thermal shield. In step c), the insulating element is applied to the inner container such that the electrodeposited copper coating faces the thermal shield.

[0053] According to one embodiment, in step b), the copper coating is electrodeposited from the copper solution onto the carrier surface.

[0054] In particular, the copper coating is deposited directly onto the surface of the support material. No additional support foil is required. The copper solution used to deposit the copper coating can be sulfuric acid or a high-purity copper solution.

[0055] In a further embodiment, the carrier surface is cylindrical, and in particular, a circular cylinder.

[0056] The carrier surface may be the cylindrical outer surface of a drum or roller. However, the carrier surface may also have any other desired geometric shape.

[0057] In a further embodiment, in step c), the copper coating is arranged such that the surface of the copper coating that is farther from the tank faces away from the inner container, and the surface of the copper coating that is facing the tank faces the inner container.

[0058] As described above, the surface facing away from the tank has a lower roughness than the surface facing the tank.

[0059] The embodiments and features described for the transport container are applied in accordance with the proposed method, and vice versa.

[0060] In this case, "an" should not necessarily be understood as strictly limiting to one element. Rather, several elements, such as two, three, or more, may be provided. Any other numeric words used herein should not be understood as meaning that a strict limitation on the number of elements strictly corresponding to them must be realized. Rather, variations in the number are possible.

[0061] Further possible implementations of the transport container and / or method also include combinations of features or embodiments described or described above or below with respect to exemplary embodiments, which are not expressly mentioned. Those skilled in the art can also add individual embodiments as improvements or additions to each of the basic forms of the transport container and / or method.

[0062] Further advantageous embodiments of the transport container and / or method form the subject matter of the dependent claims and exemplary embodiments described later for the transport container and / or method. The transport container and / or method will be described in more detail below, based on preferred embodiments, with reference to the accompanying drawings. [Brief explanation of the drawing]

[0063] [Figure 1] This is a schematic cross-sectional view of one embodiment of a transport container.

[0064] [Figure 2] This is a detailed diagram II based on Figure 1.

[0065] [Figure 3] Figure 1 is a schematic cross-sectional view of a manufacturing apparatus for producing copper coatings for transport containers.

[0066] [Figure 4] Figure 3 shows a detailed diagram IV.

[0067] [Figure 5] Figure 1 is a schematic block diagram of one embodiment of a method for manufacturing a transport container.

[0068] In the diagrams, unless otherwise specified, identical or functionally equivalent elements are given the same reference numeral.

[0069] Figure 1 is a highly simplified schematic cross-sectional view of one embodiment of a transport container 1 for liquid helium (He). Figure 2 is a detailed view II of Figure 1. Hereafter, Figures 1 and 2 will be referred to together.

[0070] Transport container 1 may also be called a helium transport container. Transport container 1 can also be used for other cryogenic fluids. Examples of cryogenic fluids or liquids, or abbreviated as cryogen, are the aforementioned liquid helium He (boiling point at 1 bar: 4.222 K = -268.928 °C), liquid hydrogen H2 (boiling point at 1 bar: 20.268 K = -252.882 °C), liquid nitrogen N2 (boiling point at 1 bar: 77.35 K = -195.80 °C), or liquid oxygen O2 (boiling point at 1 bar: 90.18 K = -182.97 °C).

[0071] The transport container 1 comprises an outer container 2. The outer container 2 can be made of, for example, stainless steel. The outer container 2 can have a length L2 of, for example, 10 meters. The outer container 2 comprises a cylindrical or cylindrical base 3, which in each case is closed on both sides of the front by cover portions 4, 5, particularly using a first cover portion 4 and a second cover portion 5. The cross-section of the base 3 can have a circular or substantially circular geometric shape. The cover portions 4, 5 are curved. The cover portions 4, 5 are curved in opposite directions such that the two cover portions 4, 5 curve outward relative to the base 3. The outer container 2 is fluid-sealed and in particular airtight. The outer container 2 has an axis of symmetry or central axis M1, and the outer container 2 is designed to be rotationally symmetric with respect to this axis.

[0072] The transport container 1 further comprises an inner container 6 for holding liquid helium He. The inner container 6 is similarly made of, for example, stainless steel. As long as helium He is in a two-phase region, a gaseous region 7 having vaporized helium He and a liquid region 8 having liquid helium He can be provided within the inner container 6. The inner container 6 is fluid-sealed, and in particular airtight, and may include a blow-off valve for controlled pressure reduction. Similar to the outer container 2, the inner container 6 comprises a tubular or cylindrical base 9, the base 9 being closed on both sides of its front by cover portions 10, 11, in particular a first cover portion 10 and a second cover portion 11. The base 9 may have a geometric shape with a circular or substantially circular cross-section.

[0073] The inner container 6, like the outer container 2, is rotationally symmetric with respect to the central axis M1. The intermediate space 12 between the refrigerant container 6 and the outer container 2 is left empty. The transport container 1 further comprises a cooling system 13 having a refrigerant container 14. A cryogenic fluid, such as liquid nitrogen N2, is contained in the refrigerant container 14. The refrigerant container 14 comprises a tubular or cylindrical base 15, which can be designed to be rotationally symmetric with respect to the central axis M1. The cross-section of the base 15 can have a circular or substantially circular geometric shape. In each case, the base 15 is closed at the front by cover portions 16, 17. The cover portions 16, 17 may be curved. In particular, the cover portions 16, 17 are curved in the same direction. The refrigerant container 14 may also have different designs.

[0074] The refrigerant container 14 can be provided with a gaseous region 18 containing vaporized nitrogen N2 and a liquid region 19 containing liquid nitrogen N2. Viewed in the axial direction A of the inner container 6, the refrigerant container 14 is positioned adjacent to the inner container 6. An intermediate space 20, which may be part of the intermediate space 12, is provided between the inner container 6, in particular the cover portion 11 of the inner container, and the refrigerant container 14, in particular the cover portion 16 of the refrigerant container 14. This means that the intermediate space 20 is also empty.

[0075] The transport container 1 further comprises a heat shield 21 associated with a cooling system 13. The heat shield 21 is located in an intermediate space 12 provided between the inner container 6 and the outer container 2 and is left empty. The heat shield 21 is either actively coolable or actively cooled using liquid nitrogen N2. In this case, “active cooling” should be understood as meaning that liquid nitrogen N2 passes through or is guided along the heat shield 21 in order to cool the heat shield 21. In this case, the heat shield 21 is cooled to a temperature approximately corresponding to the boiling point of nitrogen N2.

[0076] The heat shield 21 comprises a cylindrical or tubular base 22, the base 22 being closed on both sides by cover portions 23, 24 that close the base 22 at the front. Both the base 22 and the cover portions 23, 24 are actively cooled by nitrogen N2. The cross-section of the base 22 may have a circular or substantially circular geometric shape. The heat shield 21 is preferably designed to be rotationally symmetric with respect to a central axis M1.

[0077] The first cover portion 23 of the heat shield 21 is positioned between the inner container 6, particularly the cover portion 11 of the inner container 6, and the refrigerant container 14, particularly the cover portion 16 of the refrigerant container 14. The second cover portion 24 of the heat shield 21 faces away from the refrigerant container 14. The heat shield 21 is self-supporting; that is, it is not supported by either the inner container 6 or the outer container 2. For this purpose, a support ring may be provided on the heat shield 21, which is suspended from the control container 2 via support rods, particularly tension rods. Furthermore, the inner container 6 can be suspended from the support ring via additional support rods. Heat transfer through the mechanical support rods is partially realized by the support ring. The support ring has pockets that allow the support rods to have the maximum possible heat length. The refrigerant tank 14 includes feedthroughs for the mechanical support rods.

[0078] The heat shield 21 is fluid-permeable. This means that the intermediate space 25 between the inner container 6 and the heat shield 21 is fluid-connected to the intermediate space 12. Therefore, the intermediate spaces 12 and 25 can be emptied simultaneously. Holes or openings can be provided in the heat shield 21 to allow the intermediate spaces 12 and 25 to be emptied. The heat shield 21 is preferably made of high-purity aluminum material.

[0079] The first cover portion 23 of the heat shield 21 completely shields the refrigerant container 14 from the inner container 6. That is, looking from the inner container 6 toward the refrigerant container 14, the refrigerant container 14 is completely covered by the first cover portion 23 of the heat shield 21. In particular, the heat shield 21 completely surrounds the inner container 6. That is, the inner container 6 is completely contained within the heat shield 21, and as already mentioned, the heat shield 21 is not fluid-sealed.

[0080] To actively cool the heat shield 21, the heat shield 21 is provided with at least one, preferably several, cooling lines. For example, the heat shield 21 may have six cooling lines. The cooling lines or multiple cooling lines are fluidly connected to the refrigerant container 14, so that liquid nitrogen N2 can flow from the refrigerant container 14 to the cooling lines or multiple cooling lines. The cooling system 13 may further include a phase separator, not shown in Figure 1, configured to separate gaseous nitrogen N2 from liquid nitrogen N2. The gaseous nitrogen N2 can be released from the cooling system 13 through the phase separator.

[0081] The cooling lines or multiple cooling lines are provided not only on the base 22 but also on the cover portions 23 and 24 of the heat shield 21. The cooling lines or multiple cooling lines have an inclination with respect to a horizontal line H that is perpendicular to the direction of gravity g. In particular, the cooling lines or multiple cooling lines form an angle of more than 3 degrees with respect to the horizontal line H.

[0082] The inner container 6 also includes an insulating element 26, shown in cross-section in Figure 2. The insulating element 26 is multilayer; that is, it comprises multiple layers or coatings. Therefore, the insulating element 26 can also be referred to as a multilayer insulating element. The insulating element 26 completely encloses the inner container 6; that is, the insulating element 26 is provided not only on the base 9 but also on the cover portions 10 and 11 of the inner container 6. The insulating element 26 is provided between the inner container 6 and the heat shield 21; that is, the insulating element 26 is located within the intermediate space 25. The insulating element 26 has a highly reflective copper coating 27 on its exterior, i.e., facing the heat shield 21. The copper coating 27 is bare metal; that is, the copper coating 27 has no surface coating or oxide coating.

[0083] The actual insulation of the inner container 6 against the temperature level of liquid nitrogen N2 in the heat shield 21 is achieved by the copper coating 27. The copper coating 27 is preferably a multilayer insulation placed between the copper coating 27 and the inner container 6. Edge 2 It is a smooth foil of high-purity bare copper tightly and wrinkle-free wrapped around the number 8. Edge 2 8 comprises several layers or coatings in which layers of perforated and embossed aluminum foil 29 as reflectors and layers of glass paper 30 as spacers between the aluminum foils and as insulators in case the vacuum between the aluminum foils 29 collapses are arranged alternately. Edge 2 8 may be 10 layers. The layers of aluminum foil 29 and glass paper 30 are applied to the inner container 6 without any gaps, i.e., pressed together. Edge 2 8 may be a so-called MLI. The inner container 6 and insulating element 26 have a temperature on the outside that is approximately corresponding to the boiling point of helium He. Edge 2 During assembly of part 8, Edge 2 To ensure that all 8 layers are as isothermal as possible, care is taken to ensure that the aluminum foil layer 29 and the glass paper layer 30 are subjected to the greatest possible mechanical compression.

[0084] A gap 31 completely enclosing the inner container 6 is provided between the insulating element 26 and the heat shield 21. The gap 31 is also provided between the insulating element 26 and the cover portions 23 and 24 of the heat shield 21. The gap 31 has a gap width b31. The gap width b31 is preferably 5 mm to 15 mm, but preferably 10 mm. The gap 31 is left empty. In particular, the gap 31 is part of the intermediate space 25. The intermediate space 25 is filled with the insulating element 26 up to the gap 31.

[0085] In particular, similar to MLI, the intermediate space 12 is completely filled, thus contacting the heat shield 21 on the outside and the outer container 2 on the inside, providing further multilayer insulation. Edge 3 2 can be placed between the heat shield 21 and the outer container 2. Insulation 3 2 is provided between the respective bases 3 and 22, between the cover portion 24 of the heat shield 21 and the cover portion 4 of the outer container 2, and between the cover portion 23 of the heat shield 21 and the refrigerant container 14. Insulation 3 Similarly, 2 comprises layers or coatings in which layers of aluminum foil 33 and layers of glass paper 34 of glass silk or glass mesh cloth are arranged alternately, but these are loosely introduced into the intermediate space 12 and are separated from the aforementioned insulating element 26 of the inner container 6. Here, "loosely" means that the layers of aluminum foil 33 and glass paper 34 are not compressed, and as a result, the embossing and perforation of the aluminum foil 33 provides insulation. Edge 3 2. Therefore, the intermediate space 12 can be emptied without any problems.

[0086] As shown in Figure 3, the copper coating 27 is a coating that is electrodeposited from a copper solution 35. The copper coating 27 can also be called an ED copper coating (electrodeposited copper coating). The copper coating 27 is of high purity. Preferably, the copper coating 27 has a mass fraction of at least 99% copper, preferably at least 99.9% copper. The copper solution 35 may be sulfuric acid or a high-purity copper solution.

[0087] To produce the copper coating 27, a roller or drum 36 is immersed to a midpoint in a tank 37 filled with copper solution 35. The drum 36 may also be referred to as a carrier. Copper is electrodeposited from the copper solution 35 onto the cylindrical outer surface of the drum 36 or the carrier surface 38. Naturally, the copper is deposited only on the area of ​​the carrier surface 38 that is immersed in the copper solution 35. The copper coating 27 is deposited directly onto the drum 36. No additional carrier foil is required. The tank 37 and drum 36 are part of a manufacturing apparatus 39 for producing the copper coating 27. The manufacturing apparatus 39 may further include, for example, a lifting device that can be used to lift the drum 36 out of the tank 37 and lower it back into the tank 37.

[0088] Due to the low adhesion of the deposited copper coating 27 to the oxide support surface 38, the copper coating can be easily peeled off or lifted from the drum 36. Therefore, the copper coating 27 can be manufactured continuously. As shown in Figure 4, the electrodeposition process results in a smooth side or surface 40 facing away from the tank and a rough side or surface 41 facing the tank. The surface 40 facing away from the tank can also be referred to as the side facing the drum. The surface 41 facing the tank can also be referred to as the side or surface facing away from the drum. The wall thickness W of the copper coating is 10 to 20 μm.

[0089] During the manufacture of the transport container 1, the copper coating 27 is positioned so that the smooth surface 40 facing away from the tank faces the heat shield 21. That is, the gap 31 is defined by the surface 40 facing away from the tank and the heat shield 21. In contrast, the rough surface 41 facing the tank is... Edge 2 It faces the layers of aluminum foil 29 and glass paper 30. Therefore, only the smooth surface 40 facing away from the tank is involved in the relevant radiative exchange.

[0090] Using the gap 31, the heat shield 21 is positioned around the copper coating 27 of the insulating element 26 of the inner container 6, away from the copper coating 27 and not in contact with it. This reduces the rate of heat generation from radiation to the physically possible minimum. Heat from the surface of the inner container 6, particularly from the surface 40 of the copper coating 27 facing away from the chamber, is transferred to the heat shield 21 only by radiation and residual gas conduction.

[0091] The operating principle of transport container 1 is described below. Before the inner container 6 is filled with liquid helium He, the heat shield 21 is first cooled to at least nearly or completely to the boiling point of liquid nitrogen N2 (1.3 bara, 79.5 K) using nitrogen N2, which is initially a gas and later becomes a liquid at extremely low temperatures. The inner container 6 is not yet actively cooled. Once the heat shield 21 is cooled, any residual vacuum gas still present in the intermediate space 12 freezes on the heat shield 21. As a result, when the inner container 6 is filled with liquid helium He, the residual vacuum gas freezes on the outside of the inner container 6, thus preventing contamination of the bare metal surface of the copper coating 27 of the insulating element 26 of the inner container 6. Once the heat shield 21 and the coolant container 14 are completely cooled and the coolant container 14 is refilled, the inner container 6 is filled with liquid helium He.

[0092] This allows the transport container 1 to be moved onto a transport vehicle such as a truck or ship to transport liquid helium He. The heat shield 21 is continuously cooled by liquid nitrogen N2. In this process, liquid nitrogen N2 is consumed and boils in the cooling line of the cooling system 13. The bubbles formed in the process are sent through a phase separator, which is positioned highest in the cooling system 13 relative to the direction of gravity g. Using the phase separator, the gaseous nitrogen N2 in the cooling system 13 is blown away, and as a result, liquid nitrogen N2 can be released from the refrigerant container 14.

[0093] Because the gap 31 prevents the copper coating 27 from mechanically contacting the heat shield 21, heat can be transferred from the surface of the inner container 6 to the heat shield 21 only through radiation and residual gas conduction. The copper coating 27 is insulating Edge 2 Because it is assigned exactly to 8, Edge 2 Having good mechanical contact with 8, the copper coating 27 also has a temperature close to that of helium He. As the emissivity of the copper coating 27 decreases as the temperature decreases, heat transfer by radiation also decreases, and therefore the total heat generation rate to the inner container 6 can be reduced to less than 3.5 W over the holding time of helium He. The emissivity of the body indicates how much radiation is emitted compared to a black body, which is an ideal heat radiator.

[0094] The inner container 6 is completely enclosed by the heat shield 21, ensuring that the inner container 6 is surrounded only by surfaces having a temperature corresponding to the boiling point of nitrogen N2 (1.3 bara, 78.5 K). As a result, there is only a small temperature difference between the heat shield 21 (78.5 K) and the inner container (4.2-6 K). Consequently, the holding time of liquid helium He can be significantly extended compared to known transport containers. The insulating element 26 provides emergency insulation for the inner container 6 in the event of vacuum decay.

[0095] Figure 5 is a schematic block diagram of a method for manufacturing the transport container 1 as described above. The method includes the following steps: In step S1, an inner container 6 is provided. Step S1 may include manufacturing the inner container 6. In step S2, an electrodeposited copper coating 27 is manufactured as described above. In step S3, an insulating element 26 is provided on the outside of the inner container 6, and the insulating element 26 has the copper coating 27 as the outermost layer relative to the inner container 6. Here, "outside" means facing the heat shield 21.

[0096] The method may further include the steps of providing and / or manufacturing a refrigerant container 14; providing and / or manufacturing an inner container 6 and an outer container 2 in which the refrigerant container 14 is received; and providing and / or manufacturing a heat shield 21 in which the inner container 6 is received. In this case, a peripheral gap 31 is provided between the insulating element 26 and the heat shield 21. In step S3, the insulating element 26 is applied to the inner container 6 such that the copper coating 27 faces the heat shield 21. Furthermore, in step S3, the copper coating 27 is arranged such that the surface 40 facing away from the tank faces away from the inner container 6, and the surface 41 facing the tank faces the inner container 6.

[0097] Although the present invention has been described with reference to exemplary embodiments, the present invention can be modified in various ways. [Explanation of Symbols]

[0098] 1. Transport container 2 Outer container 3 base 4. Cover section 5. Cover section 6 Inner container 7. Gas Region 8 liquid area 9 base 10 Cover section 11 Cover section 12 Intermediate space 13 Cooling System 14 Refrigerant container 15 base 16. Cover section 17. Cover section 18. Gas Region 19 Liquid area 20 Intermediate space 21 Shields 22 Base 23 Cover section 24 Cover section 25 Intermediate space 26 Insulating elements 27 Copper coating 28 Absolute edge 29 Aluminum foil 30 glass paper 31 Gap 32 Absolute edge 33 Aluminum foil 34 Glass paper 35 Copper solution 36 drums 37 tanks 38 Carrier surface 39 Manufacturing equipment 40 surface 41 Surface A-axis b31 Gap width g direction of gravity H horizontal line Helium H2 Hydrogen L2 Length M1 center axis N2 Nitrogen O2 Oxygen S1 process S2 process S3 process W wall thickness

Claims

1. A helium (He) transport container (1) comprising: an inner container (6) for receiving helium (He); an insulating element (26) provided on the outside of the inner container (6); a refrigerant container (14) for receiving cryogenic fluid (N2); an outer container (2) that receives the inner container (6) and the refrigerant container (14); and a heat shield (21) that can be actively cooled using the cryogenic fluid (N2) and that receives the inner container (6), wherein A peripheral gap (31) is provided between the insulating element (26) and the heat shield (21), and the insulating element (26) has an electrodeposited copper foil (27) facing the heat shield (21), A transport container wherein the copper foil has a relatively smooth surface facing the heat shield and a relatively rough surface facing away from the heat shield.

2. The transport container according to claim 1, wherein the copper foil (27) has a wall thickness (W) of 10 μm to 20 μm.

3. The transport container according to claim 1 or 2, wherein the insulating element (26) is fixed to the outside of the inner container (6).

4. The transport container according to any one of claims 1 to 3, wherein the insulating element (26) further comprises a multilayer insulation (28) disposed between the inner container (6) and the copper foil (27).

5. The transport container according to claim 4, wherein the multilayer insulation (28) has a plurality of layers in which layers of aluminum foil (29) and layers of glass paper (30) are arranged alternately.

6. The transport container according to claim 5, wherein the layer of aluminum foil (29) and the layer of glass paper (30) are applied to the inner container (6) without any gaps.

7. The transport container according to any one of claims 1 to 6, further comprising a multilayer insulation (32) disposed between the heat shield (21) and the outer container (2).

8. The transport container according to claim 7, wherein the multilayer insulation (32) has a plurality of layers in which layers (a) of aluminum foil (33) and layers (b) of glass silk, glass mesh cloth, or glass paper (34) are arranged alternately.

9. The transport container according to claim 8, wherein the layer (a) of aluminum foil (33) and the layer (b) of glass silk, glass mesh cloth, or glass paper (34) are applied to the heat shield (21) with gaps between them.

10. The transport container (1) according to any one of claims 1 to 9, wherein the central axis (M1) of the transport container (1) is oriented horizontally.

11. A method for manufacturing a helium transport container (1), a) Step (S1) to provide an inner container (6) for receiving helium (He), b) The process (S2) for manufacturing the electrodeposited copper foil (27), c) Step (S3) of providing an insulating element (26) to the outside of the inner container (6), wherein the insulating element (26) has the copper foil (27) as the outermost layer relative to the inner container (6), d) A step of providing a heat shield (21) that receives the inner container (6) and the insulating element (26), wherein a peripheral gap (31) is provided between the insulating element (26) and the heat shield (21), e) A method comprising the step of providing the inner container (6), the insulating element (26), and the outer container (2) in which the heat shield (21) is received.

12. In step b), the copper foil (27) is electrodeposited from the copper solution (35) onto the carrier surface (38). The method according to claim 11, wherein the electrodeposited copper foil (27) is removed from the carrier surface (38) and used as the outermost layer of the insulating element (26).

13. The method according to claim 12, wherein the carrier surface (38) is cylindrical.

14. The method according to any one of claims 11 to 13, wherein in step c), the copper foil (27) has a relatively smooth surface and a relatively rough surface, and the copper foil (27) is arranged such that the relatively rough surface faces the inner container (6) and the relatively smooth surface of the copper foil (27) faces away from the inner container (6).

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