Connection device for low-temperature conduit and low-temperature conduit

Abstract

A connection device (1) for a cryogenic conduit (10) having an inner conduit element (11) and an outer conduit element (12) surrounding the inner conduit element (11) at a distance (A) such that a space (13) is formed between the inner conduit element (11) and the outer conduit element (12) in at least one portion, the connection device (1) having an inner connection element (2) arranged on the inner conduit element (11) at at least one end of the conduit (10), an outer connection element (3) arranged on the outer conduit element (12) at least said end of the conduit (10), and a spacer element (4) arranged between the inner connection element (2) and the outer connection element (3) and closing the space (13) from the environment, the spacer element (4) being formed as a grooved membrane disk and arranged in a plane, the plane extending perpendicular to the longitudinal axis of the conduit (10) at least at said end.

Description

[Technical field]

[0001] The invention relates to a connection device for a cryogenic conduit according to claim 1 and to a cryogenic conduit according to claim 16. [Background technology]

[0002] Currently, so-called Johnston couplings are commonly used in industry and research for connecting conduits for transporting cryogenic liquids.

[0003] EP 3 670 999 A shows a known Johnston coupling in which the coupling plug is mechanically connected with a linear displacement unit, which allows the coupling plug to be inserted centered relative to the coupling socket without the coupling plug or the coupling socket rubbing against each other during the coupling process.

[0004] To adequately prevent heat ingress, the known connections (and basically any other type of Johnston joint) are constructed relatively long in the axial direction and insulated not only with a vacuum but also (in a corresponding manner) with a multi-layer insulation (Multi-Layer-Insulation - MLI). To obtain the connection, a long male plug part is inserted into an equally long female plug or socket part, thus establishing the longest possible heat ingress path. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] European Patent Application Publication No. 3670999 Summary of the Invention [Problem to be solved by the invention]

[0006] Although this basically makes it possible to obtain good thermal insulation effects, the axial length of the joints is too intensive in terms of construction space for the short conduits which are very much prevalently used, for example, in (automotive) mobile applications.

[0007] There is a need for connecting conduits in low temperature conduits, or in such conduits in general, which have an equally good thermal insulation effect but are of a shorter axial configuration. [Means for solving the problem]

[0008] The problem is solved according to the invention by a connection device for a cryogenic conduit having the features of claim 1 and by a cryogenic conduit having the features of claim 16 .

[0009] Advantageous developments are defined in the respective associated dependent claims.

[0010] A connection device for a cryogenic conduit according to the present invention has an inner conduit element and an outer conduit element, the outer conduit element surrounding the inner conduit element at a distance such that a space is formed between the inner and outer conduit elements in at least one portion, the connection device comprising an inner connection element arranged on the inner conduit element at at least one end of the conduit, an outer connection element arranged on the outer conduit element at at least an end portion of the conduit, and a spacer element arranged between the inner and outer connection elements, closing the space from the environment, the spacer element being formed as a grooved membrane disk and arranged in a plane, the plane extending perpendicular to the longitudinal axis of the conduit at least at the end portion.

[0011] A grooved membrane disk is a thin, preferably circular, disk that is not flat or horizontal, but has closed grooves or corresponding corrugation peaks and valleys that circumferentially surround the disk. Thus, the length of the heat transfer path from the center to the edge of the disk is relatively long - much longer than the geometric radius of the disk. By arranging the disk perpendicular to the longitudinal axis of the conduit, it is possible to significantly reduce the axial length of the structure without compromising the thermal insulation.

[0012] Such connecting devices are particularly and accordingly formed to cooperate releasably with a corresponding connecting device, which can in particular be achieved by an outer connecting element of a given connecting device cooperating releasably with an outer connecting element of another connecting device, and similarly for the respective inner connecting element.

[0013] In order to be able to produce a composite cryogenic conduit, it is particularly advantageous if one of the two connection devices is arranged at each end of the cryogenic conduit.

[0014] The connection can be fixed as in the prior art, preferably in the region of the outer connecting element, by means of a clamping ring or the like.

[0015] In the region of the inner connecting elements, the two connecting devices can be configured in such a way that one of the two inner connecting elements can be inserted into the respective other inner connecting element. For sealing, sealing rings or the like can be used.

[0016] A cryogenic conduit having an inner conduit element and an outer conduit element according to the present invention, the outer conduit element surrounding the inner conduit element at least in one portion at a distance such that a space is formed between the inner and outer conduit elements, has at least one end, and preferably both ends, a connecting device according to the present invention, most preferably a connecting device at each end which is complementary to the connecting device at the other end.

[0017] In addition to the disclosure of the detachable connection in a conduit for cryogenic fluids with a short axial extension, the following further aspects should be taken into account in the course of corresponding developments of the invention: - As complete as possible, i.e. vacuum and MLI insulation over the majority of the pipe length Heat resistant up to 250°C for quick ventilation · Avoidance of icing during operation by correspondingly sufficient insulation, preferably by vacuum and MLI, and long heat transfer paths to the ends Preventing condensation and concentration of atmospheric oxygen, in particular by preventing contact between the outside air and components at cryogenic temperatures (e.g. by providing external seals) Adjustment of absorbent material to maintain working vacuum (leaks, outgassing, etc.) Adjustment of vacuum port for exhaust In a first development of the connection device according to the invention, the grooved membrane disk has a highly corrugated shape. In this document this means a highly formed corrugated shape in which the maximum possible formability of the material used is utilized. In addition, it is possible to carry out a heat treatment between the individual deformation steps to obtain a higher degree of deformation in order to enhance the shape. Alternatively, hot working can be used as a manufacturing process. The height difference between one corrugation crest and one corrugation trough is preferably about twice, preferably twice and most preferably 0.5 times the distance between two adjacent corrugation crests. This makes it possible to provide a sufficiently long path for the heat ingress in order to well insulate the connection.

[0018] In a second development of the connection device according to the invention, the grooved membrane disk is made of a metallic material, preferably an austenitic chromium-nickel steel with a thermal conductivity of about 15 W / (m·K), so as to be thin-walled in order to form the smallest possible heat conduction path, which results in good weldability and diffusion density.

[0019] The grooved membrane disk may have a number of beads to support the grooved membrane disk against the atmosphere.

[0020] It has proven to be particularly advantageous if the grooved membrane disc has beads, preferably 3 to 6 radial beads, which are most preferably formed in the direction of the folded weld beads in order to limit the required axial construction space.

[0021] In a further development of the connecting device according to the invention, the inner connecting element is formed as an essentially smooth cylindrical sleeve part, which makes it possible to easily establish a good connection to a further connecting device.

[0022] In a further development according to the invention, the outer connecting element has a larger cross-section at its free end than at its other end, and the grooved membrane disk is arranged in the area of ​​the larger cross-section at the outer connecting element, which allows the use of a comparatively larger grooved membrane disk, thereby improving the thermal insulation.

[0023] In order to further improve the support of the grooved membrane disc, in a further development of the connection device according to the invention, a support element is arranged (axially) adjacent to the grooved membrane disc for supporting the grooved membrane disc against the atmospheric pressure, thereby also obtaining shear stiffening during the joining of the connection device. The support element is preferably manufactured from a material with low thermal conductivity. The support element supports the grooved membrane disc and can additionally provide shear stiffening for the joining of the joint (connection device).

[0024] Furthermore, the support element has at least one first outer abutment portion, where the support element abuts from the inside against the outer connecting element, preferably in a larger cross-sectional area, and / or the support element has at least one second inner abutment portion, where the support element abuts from the outside against the inner connecting element, and further the support element has at least one connecting portion, which connects the outer abutment portion and the inner abutment portion, which connecting portion has an extension that deviates from the extension in the radial direction, preferably has a circumferential and / or axial direction component, such that the length of the connecting portion is preferably maximized. The support element has the smallest possible cross-section and contact surface in order to further minimize the heat transfer.

[0025] The support elements are preferably each configured as specifically illustrated in the drawings.

[0026] The support element has a number of spring elements for radially locking between the inner and outer connecting elements to securely fasten the support element.

[0027] In order to obtain the desired heat resistance up to 250° C., particularly for rapid ventilation, in further developments of the connecting device according to the invention the support element can be manufactured from a ceramic material, preferably porcelain, most preferably titanium dioxide, or from a plastic, preferably epoxy, polyamide, polyimide, PEEK, PTFE or PCTFE.

[0028] In order to improve the robustness of the connecting device according to the present invention, in particular when connected to another corresponding connecting device, the support element further has an axial extension component, which is used for shear support of the inner conduit element and / or the inner connecting element relative to the outer conduit element and / or the outer connecting element.

[0029] In a further development of the connecting device according to the invention, a cut-out is arranged in the outer connecting element for evacuating the space, which cut-out is preferably arranged in an adapter tube protruding from the outer connecting element.

[0030] In a further development of the connection device according to the invention, an absorbent material is preferably arranged in the space, preferably in fluid communication with the recess, and preferably surrounds the inner duct element in the form of a ring. The absorbent material can preferably be silica gel, most preferably aluminum silicate with a porous microstructure. Its role is to absorb free molecules in the vacuum space in order to prevent conductive heat transfer.

[0031] In a corresponding development of the connection device according to the invention, it is particularly preferred that the outer connection element has a receiving structure for receiving and in particular axially positioning the absorbent material, in particular a receiving area limited by at least one axially recessed portion or an axially and / or radial wall, in which in the region of the receiving structure the material of the outer connection element has cutouts which establish fluid communication between the space and the absorbent material. The receiving structure preferably has a (relatively long) axial extension component (with respect to the extension of the conduit element), which is preferably intended for thermal insulation by establishing a long heat transfer path.

[0032] This allows the absorbent material to be positioned well and securely, without impeding the evacuation of the space.

[0033] In order to improve the insulation, in a further development of the conduit according to the invention the space is preferably evacuated or can be evacuated via a recess.

[0034] In a further development of the conduit according to the invention, the outer conduit element and / or the inner conduit element can be formed as an at least partially metallic corrugated hose, which makes the conduit flexible.

[0035] In a further development of the conduit according to the invention, at least the inner conduit element can be at least partially surrounded by a protective covering, preferably a mesh hose, which makes it possible to support and protect the conduit element. The mesh also advantageously serves to increase the pressure resistance of the inner hose (inner conduit element), which would otherwise be lengthened in an undesirable manner.

[0036] In a further development of the pipe according to the invention, at least the inner pipe element and possibly the protective coating can be at least partially surrounded by a thermal insulation, preferably a multi-layer insulation, which further improves the insulation effect against thermal radiation.

[0037] Finally, in a further development of the conduit according to the invention, the inner connecting element can protrude at least at one end of the conduit axially facing the grooved membrane disk, preferably by being guided through a recess in the grooved membrane disk, which facilitates connection to the conduit element to be connected.

[0038] Further characteristics and advantages of the invention emerge from the following description of exemplary embodiments with reference to the drawings. [Brief description of the drawings]

[0039] [Figure 1] 2 is a partial cross-sectional view of a connection device according to the present invention; [Diagram 2] FIG. 4 is a detailed partial cross-sectional view of another configuration of a connection device according to the present invention. [Diagram 3] 1A-1D are diagrams of possible configurations of support elements in a connection device according to the invention; [Figure 4] 4A-4D are diagrams of further possible configurations of the support element in the connection device according to the invention; [Diagram 5] 4A-4D are diagrams of further possible configurations of the support element in the connection device according to the invention; [Figure 6] 6 shows a longitudinal section of a connecting device according to the invention with the support element of FIG. 5; [Figure 7]7 shows further details of the conduit arrangement with the connecting arrangement of FIG. 6; [Figure 8] 1A to 1C are partial views showing possible configurations of the connecting device according to the invention in the region of the outer connecting element. [Figure 9] Detail of the configuration according to Fig. 8a). [Figure 10] FIG. 10 is a view of the outer connection device according to the configuration of FIG. 9 in a separated state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] In figure 1 the arrangement of a connection device for a cryogenic conduit according to the invention is illustrated in a partial cross-section. The reference L indicates the longitudinal axis of the connection device, which is generally designated 1. The reference 10 indicates the cryogenic conduit as a whole.

[0041] As can be seen from the view of FIG. 1, the cryogenic conduit 10 comprises an inner conduit element, designated 11, formed as a ring-shaped corrugated hose. The cryogenic conduit further comprises an outer conduit element, designated 12, also formed as a ring-shaped corrugated hose. The outer conduit element 12 surrounds the inner conduit element 11 with a distance A (in the radial direction), so that a space 13 is established between the inner conduit element 11 and the outer conduit element 12. The cryogenic conduit 10 or the connecting device 1 comprises an inner connecting element 2, which is arranged at the end of the conduit 10 shown in the figure, preferably by means of a materially integrated joint, at the end of the inner conduit element 11. The inner connecting element 2 is formed essentially as a circular cylindrical sleeve. The cryogenic conduit 10 or the connecting device 1 further comprises an outer connecting element 3, which is likewise arranged at the end of the conduit 10 shown in the figure, preferably by means of a materially integrated joint, at the end of the outer conduit element 12. The outer connecting element 3 is also sleeve-shaped, but has three regions 3.1 to 3.3 with different diameters. The connecting device 1 further comprises a spacer element 4, which is arranged between the inner connecting element 2 and the outer connecting element 3 - here in the region 3.3 with the largest diameter - and is preferably materially joined to the inner connecting element 2 as well as to the outer connecting element 3. The spacer element 4 closes the space 13 to the outside against the environment and is in particular formed as a grooved membrane disk, the grooves 4a of which are arranged concentrically around a central cutout 4b. Through the cutout 4b the inner connecting element 2 projects outward relative to the grooved membrane disk 4. The grooves 4a result from a succession of concentrically arranged corrugation crests and corrugation troughs, the height difference H between the corrugation crests and corrugation troughs being formed relatively large in relation to the wavelength I (the distance between two adjacent corrugation crests), so that the longest possible heat transfer path is formed between the inner connecting element 2 and the outer connecting element 3. This results in the entire connecting device 1 having a relatively short structure in the axial direction. The grooved membrane disc 4 is disposed in a plane E (illustrated or imaginary) that is oriented perpendicular to the longitudinal axis L of the cold conduit 10 .

[0042] A mesh hose 14 is arranged around the inner duct element 11, which is itself surrounded by a multi-layer insulation 15. The mesh hose 14 and the multi-layer insulation 15 extend axially up to the grooved membrane disk 4.

[0043] Preferably, all of the elements described thus far, except for the multi-layer insulation 15, are formed from thin-walled metallic material, preferably steel, especially stainless steel.

[0044] In the region 3.2, the outer connecting element 3 has a receiving structure 3a for the absorbent material, which is not shown in Fig. 1. The receiving structure 3a is formed from a ring-shaped perforated plate with an approximately U-shaped cross section, which cooperates with the outer connecting element 3 with its free leg, preferably by means of a material-integral joint, in such a way that a space 3b is formed between the outer connecting element 3 and the receiving structure 3a for the absorbent material circulating in a ring-like manner, the space reaching with its axial end to the grooved membrane disk 4.

[0045] The receiving structure 3a is also used to shear support element 2 relative to element 3, as can be better seen, for example, in FIG.

[0046] In the region 3.3, the outer connection element 3 has at its end 3d a further circumferential recess (groove) into which a sealing element, for example an O-ring, can be inserted in order to establish a sealed connection with the outer connection element (not shown) of another cryogenic conduit (not shown), as for the inner connection element 2.

[0047] In the upper region of Fig. 1 the outer connecting element 3 preferably has a radially outward cutout, which is not visible in Fig. 1. In the region of the cutout an adapter tube 3c is arranged, only the lower end of which is visible in Fig. 1 in the region of the space 3b. Via the adapter tube 3c the space 13 can be evacuated for vacuum insulation of the inner conduit element 11, an absorbent material being used to prevent conductive heat transfer by absorbing free molecules in the vacuum space.

[0048] 2 shows a geometrically slightly modified configuration in the region of the outer connection element 3 and the receiving structure, in which the absorbent material 5 is also shown. Otherwise, identical reference numbers indicate elements which are identical or at least perform the same function. For the sake of clarity, not all elements are referenced.

[0049] At 6 an additional support element, preferably made of plastic, can be seen. The support element ensures axial support of the grooved membrane disc, as far as possible without establishing a substantial heat conduction path between the inner connecting element 2 and the outer connecting element 3. For this purpose, the support element 6 preferably has as small an abutment surface as possible in contact with the connecting elements 2, 3. The support element 6 is arranged in the central region 3.2 of the outer connecting element.

[0050] Figure 3 shows a merely suggestive view of the conduit 10 and a detailed view of the support element 6. The support element comprises two concentric rings 6a, 6b, of which the outer ring 6a abuts, preferably from the inside, against the outer connection element 3 (see Figure 2), whereas the inner ring 6b abuts from the outside against the receiving structure 3a (see Figure 2). Both rings 6a, 6b are connected with a directional component in the circumferential direction via a curved (connection) portion 6c.

[0051] FIG. 4 shows another variant of the support element 6, which does not have a closed outer ring, but a number of mushroom-like structures 6d extending outward in the circumferential direction, which can also abut against the outer connection element 3 from the inside (by rear projections) to ensure shear support. The inner ring 6b is arranged radially spaced from the inner connection element 2, the abutment here being effected by a radial extension 6d' of the structure 6d, which can also contribute to the shear support (by abutting against the shoulder between elements 14 and 15). Two sealing elements (sealing rings) 2a are arranged at the ends of the connection element 2 for a sealing connection with further connection elements (not shown).

[0052] In FIG. 5, a further configuration of the support ring 6 is shown. The support ring has two outer rings 6a, 6a' arranged at different radii and also offset in the axial direction starting from an inner ring 6b. Details can also be seen from FIG. 6, which is described below. The rings 6a, 6a' are connected to the inner ring 6b via (double) radial spokes 6c', 6c"; the spokes 6c" corresponding to the ring 6a' have or establish an axial extension component. The axial extension component is used for the shear support of the inner hose (inner duct element 11, see FIG. 1) against the outer hose (outer duct element 12, see FIG. 1). For this purpose, a locking lug or lug is provided on the inside at 6e (see FIG. 6) for axial fixation. This connection is preferably performed by external fitting or snapping.

[0053] FIG. 6 illustrates the cooperation of the support element 6 of FIG. 5 with the outer connection element 3, which is formed substantially similarly to FIG. 1 or 2 (except for the absorbent receiving structure, which is not present here). The support element abuts on the area 3.2 of the connection element 3 at the outer ring 6a' and on the area 3.3 at the outer ring 6a (see FIGS. 1 and 2). Reference 7 denotes an optional outer sleeve, which bridges the connection area of ​​the outer corrugated hose 12 with the connection element 3. The spokes 6c' abut in a flat bearing against the grooved membrane disc 4. As mentioned above, the support element can obtain an effective shear support by engaging a corresponding recess in the inner connection element 2 at a radial (preferably circumferential) projection or a plurality of locking projections at 6e. At the radially outer side, the support element 6 can be formed with a spherical cross section so as to fit snugly into a complementary recess (referenced X) in the connection element 3.

[0054] Figure 7 shows an enlarged view of the arrangement according to figure 6. At 8 one can see a further support element, in particular made of plastic, which ensures a reliable and durable spacing between the inner duct element 11 and the outer duct element 12 at a central axial position along the duct 10.

[0055] 8 comprises three partial views a) to c), in which a perspective view (respectively the upper view) and a longitudinal section view (respectively the lower view) of each possible configuration of the connection device 1 are shown.

[0056] Partial view a) corresponds approximately to the configuration of FIG. 1. Here, the cutout at 3e is also visible. The absorbent material 5 is also shown. The absorbent material is positioned in a complementary engagement between the absorbent cage (receiving structure 3a, see FIG. 1) and the support element.

[0057] According to part b), the connecting element 3 has a ridge 3f at a partial circumference, which is used as a positioning structure for the absorbent material 5, but leaves the area of ​​the cutout 3e free. Otherwise, Fig. 8b) corresponds to Fig. 8a).

[0058] In the partial view c) the ridge 3f is formed all around and extends into the area of ​​the recess 3e, so that the absorber 5 is also arranged there, which is clamped radially outwards by means of a clamping plate 5a.

[0059] Figure 9 shows further details of an arrangement which otherwise generally corresponds to Figure 2 (but without the supporting elements in the drawing). The adapter tube 3c for the exhaust and the arrangement of the receiving structure 3a are easily visible.

[0060] The latter also appears from the last figure 10, which shows only the outer connecting element 3 of figure 9. Here the notches 3e (in the radial direction) and the notches 3h (in the axial direction) are easily visible, the latter allowing the passage of the connecting element 2 (see figure 9). The receiving structure 3a has a number of notches 3g, which ensure fluid communication for the evacuation of the space 13 through / through the absorbent material 5.

[0061] The absorber cage (accommodation structure 3a) is here designed in such a way that it additionally provides axial support (shear) for the inner duct element 11 (FIG. 9) relative to the outer duct element 12 and thereby provides the longest possible heat transfer path. It is thus possible to completely omit or at least to make smaller the additional support element for the grooved membrane disk providing shear support (see element 6 in FIG. 6).

Claims

1. A connection device (1) for a low-temperature conduit (10) comprising an inner conduit element (11) and an outer conduit element (12), the outer conduit element (12) surrounding the inner conduit element (11) in at least one portion and with a distance (A) such that a space (13) is formed between the inner conduit element (11) and the outer conduit element (12), an inner connection element (2) arranged on the inner conduit element (11) at at least one end of the cold conduit (10); an outer connection element (3) arranged on the outer conduit element (12) at least at the end of the cold conduit (10); a spacer element (4) arranged between the inner connection element (2) and the outer connection element (3) for closing off the space (13) from the environment, The connecting device (1), characterized in that the spacer element (4) is formed as a grooved membrane disk and is arranged in a plane (E), which plane (E) extends perpendicular to the longitudinal axis (L) of the cold conduit (10) at least at the end.

2. The connection device (1) according to claim 1, characterized in that the grooved membrane disc (4) has a highly corrugated shape, so that the height difference (H) between one corrugation crest and one corrugation trough is about twice, preferably twice, most preferably 0.5 times the distance (I) between two adjacent corrugation crests.

3. 3. A connection device (1) according to claim 1 or 2, characterized in that the grooved membrane disc (4) is made of a metallic material so as to be thin-walled.

4. 4. A connecting device (1) according to any one of claims 1 to 3, characterized in that the grooved membrane disc (4) has a number of beads.

5. 5. A connecting device (1) according to claim 4, characterized in that the grooved membrane disc has at least one, preferably 3 to 6, beads, preferably in radial direction.

6. 6. A connecting device (1) according to any one of claims 1 to 5, characterized in that the inner connecting element (2) is formed as an essentially smooth cylindrical sleeve section.

7. said outer connecting element (3) having a larger cross section at its free end than at its other end, 7. A connecting device (1) according to any one of claims 1 to 6, characterized in that the grooved membrane disk (4) is arranged in the area of ​​larger cross section (3.3) of the outer connecting element (3).

8. 8. A connection device (1) according to claim 1, characterized in that adjacent to the grooved membrane disc (4) a support element (6) is arranged for supporting the grooved membrane disc (4) against atmospheric pressure.

9. the support element (6) has at least one first outer abutment portion, in which the support element (6) abuts from the inside against the outer connecting element (3), preferably in the area of ​​large cross section (3.3) according to claim 7; and / or the support element (6) has at least one second inner abutment portion, at which the support element (6) abuts from the outside against the inner connecting element (2), 9. A connecting device (1) according to claim 8, characterized in that the support element (6) has at least one connecting portion (6c, 6c', 6c"), which connects the outer abutment portion with the inner abutment portion, and which connecting portion (6c, 6c") has an extension that deviates from a radial extension and preferably has a circumferential and / or axial directional component such that the length of the connecting portion (6c, 6c', 6c") is preferably maximum.

10. 10. The connecting device (1) according to claim 8 or 9, characterized in that the support element (6) has a number of spring elements for radially locking between the inner connecting element (2) and the outer connecting element (3).

11. 11. The connection device (1) according to any one of claims 8 to 10, characterized in that the support element (6) is made from a ceramic material, preferably porcelain, most preferably titanium dioxide, or from a plastic, preferably epoxy, polyamide, polyimide, PEEK, PTFE or PCTFE.

12. A connection device (1) according to any one of claims 8 to 11, characterized in that the support element (6) has an axial extension component for shear support of the inner conduit element (11) and / or the inner connection element (2) relative to the outer conduit element (12) and / or the outer connection element (3).

13. A connection device (1) according to any one of claims 1 to 12, characterized in that in the outer connection element (3) a notch (3e) for venting the space (13) is arranged, said notch (3e) being preferably arranged in an adapter tube (3c) protruding from the outer connection element (3).

14. A connection device (1) according to any one of claims 1 to 13, characterized in that within the space (13) an absorbent material (5) is arranged in fluid communication with the cutout (3e), preferably as described in claim 13, and is preferably silica gel, most preferably aluminum silicate having a porous microstructure, and the absorbent material (5) preferably surrounds the inner conduit element (2) in a ring-like shape.

15. 15. The connection device (1) according to claim 14, characterized in that the outer connection element (3) has a receiving structure (3a) for receiving and in particular axially positioning the absorbent material (5), in particular a receiving area (3b, 3f) limited by at least one axial recess or by walls in the axial and / or radial direction, and in the area of ​​the receiving structure (3a) the material of the outer connection element (3) has notches (3g) establishing fluid communication between the space (13) and the absorbent material (5), and the receiving structure (3a) has an axial extension component for thermal insulation by establishing a preferably long heat transfer path.

16. It has an inner duct element (11) and an outer duct element (12). a low-temperature conduit (10) in which the outer conduit element (12) surrounds the inner conduit element (11) at least in one portion at a distance (A) such that a space (13) is formed between the inner conduit element (11) and the outer conduit element (12); A cryogenic conduit (10), characterised in that at least one end, preferably both ends, of the cryogenic conduit comprises a connection device (1) according to any one of claims 1 to 15.

17. A cold conduit (10) according to claim 16, characterized in that the space (13) is evacuated or can be evacuated via the cut-out (3e), preferably as defined in claim 13.

18. 18. The cold conduit (10) according to claim 16 or 17, characterized in that the outer conduit element (12) and / or the inner conduit element (11) are at least partially formed as metallic corrugated hoses.

19. 19. The cryogenic conduit (10) according to any one of claims 16 to 18, characterized in that at least the inner conduit element (11) is at least partially surrounded by a protective covering (14), preferably a woven fabric hose.

20. A low-temperature conduit (10) according to any one of claims 16 to 19, characterized in that at least the inner duct element (11) and possibly the protective covering (14) according to claim 19 are at least partially surrounded by a thermal insulation (15), preferably a multi-layer thermal insulation.

21. 21. The cold conduit (10) according to any one of claims 16 to 20, characterized in that the inner connecting element (2) protrudes at least at one end of the cold conduit (10) axially facing the grooved membrane disc (4), preferably by the inner connecting element (11) being guided through a notch (4b) in the grooved membrane disc (4).

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