FITTING FOR CRYOGENIC PIPES

Abstract

Coupling for cryogenic conduits. A coupling (1) for cryogenic conduits is proposed, comprising a coupling socket (3) and a coupling plug (2), wherein: the coupling plug (2) has a first inner, media-carrying pipe element (13) and a first outer pipe element (14), which coaxially surrounds the first inner pipe element (13) at a radial distance, between which first pipe elements (13, 14) an evacuable first free space (56) is formed; the coupling socket (3) has a second inner pipe element (23, 29) and a second outer pipe element (24), which coaxially surrounds the second inner pipe element (23, 29) at a radial distance, between which second pipe elements (23, 24) an evacuable second free space (55) is formed; the first inner pipe element (13) with the second inner pipe element (23, 29) is detachably connected or connectable;the first outer pipe element (14) is detachably connected or connectable to the second outer pipe element (24); characterized by a drive element (36) that is connected or connectable to the coupling plug (2) and that has a first engagement structure that is complementary to a second engagement structure on the coupling socket (3), or that b) has a first engagement structure that is complementary to a second engagement structure on the coupling plug (2);wherein, after the first engagement structure and the second engagement structure have been brought into contact, an axial relative movement of the coupling plug (2) and coupling socket (3) is caused or can be caused by a rotational movement about a common longitudinal axis (L) of the pipe elements (13, 14, 23, 24) exerted from the outside on the drive element (36), whereby a fluid-tight connection is created or can be created between the first inner pipe element (13) and the second inner pipe element (23, 29). (Figure 3);

Description

Title of the invention: Coupling for cryogenic conduits

[0001] The invention relates to a coupling for cryogenic conduits (conduits for conveying cryogenic media, such as liquid helium or hydrogen) according to the preamble of claim 1.

[0002] Such a coupling can be designed, in particular, as a plug-in coupling for cryogenic conduits and typically comprises a coupling socket and a coupling plug, wherein the coupling socket and the coupling plug each have an inner tube element and an outer tube element arranged coaxially to the inner tube element. In a connected state, the coupling plug is inserted into the coupling socket. Furthermore, in the connected state, the coupling socket and the coupling plug are detachably connected to one another by a first connection located at one end, referred to as the "hot" end, in the region of their outer tube elements. Additionally, in the connected state, a gap between the coupling socket and the coupling plug in the region of their inner tube elements is sealed by a gasket at another end, referred to as the "cold" end.The coupling socket and coupling plug are usually made of a metal, preferably (stainless) steel.

[0003] Such couplings are also known as Johnston couplings. Examples are known from DE 41 07 652 A1 or EP 3 339 713 B1. The seal against the system pressure takes place in the so-called hot part of the coupling.

[0004] Due to the warm seal, both so-called insulation pipes, i.e., the inner pipe element of the coupling socket and the outer pipe element of the coupling plug, are subjected to (generally atmospheric) ambient pressure. Particularly in the case of the insulation pipe of the coupling plug (hereinafter also referred to as "plug"), this creates a risk of bulging, which is why, according to the prior art, this component had to be dimensioned with correspondingly robust, thick walls. This has the disadvantageous consequence, among others, of increased heat input at the cold end of the coupling.

[0005] Furthermore, a gap formed between the outer tube element of the plug and the inner tube element of the coupling socket (hereinafter also referred to as "socket") is regularly partially filled with cold liquid (the cryogenic medium) due to insufficient sealing at the cold end, and there is a risk that a thermally insulating gas cushion between a sealing element located at the warm end and this liquid will be overcome by the liquid and consequently the sealing element will be cooled. This causes the sealing element to become brittle, and the function of the seal is no longer guaranteed.

[0006] This circumstance means that such couplings must preferably be positioned such that a normal vector of the coupling separation plane has a positive component parallel to the gravitational vector. In other words, the couplings cannot be installed completely horizontally, which correspondingly restricts their possible applications.

[0007] From DE 10 2022 110 880 A1, another connection arrangement or coupling for a cryogenic line with an inner line element and an outer line element is known, in which a spacer element, arranged between an inner connecting element and an outer connecting element and closing off a free space between the two line elements from the environment, is designed as a grooved membrane disk and is arranged in a plane that extends transversely to a longitudinal axis of the line. This results in a relatively short axial extension, and a sufficiently long path for the incident heat can still be provided to thermally insulate the connection well. However, here too, the problem described above for Johnston couplings due to insufficient sealing at the cold end can occur.

[0008] The invention is based on the objective of further developing a coupling of the aforementioned type in such a way as to achieve an improved seal at the cold end. This is intended to reduce the risk of cooling down the "warm" sealing element and the heat input at the cold end of the coupling.

[0009] This problem is solved according to the invention by a coupling having the features of claim 1. Advantageous embodiments are defined in the dependent claims.

[0010] An invention according to a coupling for cryogenic conduits with a coupling bushing The coupling plug initially provides that the coupling plug has a first inner, media-carrying pipe element and a first outer pipe element that coaxially surrounds the first inner pipe element at a radial distance. An evacuable first free space is formed between these two first pipe elements. The coupling socket has a second inner pipe element and a second outer pipe element that coaxially surrounds the second inner pipe element at a radial distance. An evacuable second free space is formed between these two second pipe elements. The first inner pipe element is detachably connected or connectable to the second inner pipe element. The first outer The piping element is detachably connected or connectable to the second outer piping element.

[0011] This previously known arrangement is now characterized according to the invention by an additional drive element that is connected or connectable to the coupling plug and that has a first engagement structure that is designed to be complementary to a second engagement structure on the coupling socket, or vice versa. Furthermore, according to the invention, it is provided that after the first engagement structure and the second engagement structure have been brought into engagement by a rotational movement about a common longitudinal axis of the pipe elements (i.e., a corresponding torque) applied to the drive element from the outside, an axial relative movement of the coupling plug and coupling socket is caused or can be caused. This creates or allows for the formation of a secure and defined fluid-tight connection between the first inner pipe element and the second inner pipe element at the cold end.

[0012] It is therefore proposed according to the invention to use an additional drive element to effect an axial relative movement of the inner pipe elements in order to thereby form the connection at the cold end in a process-reliable manner by targeted and definable rotational action (i.e. a torque) from outside on the drive element and to avoid leakage of process fluid (i.e. cryogenic medium) and the associated problems.

[0013] In this context, the present invention proposes two basic embodiments or variants, which will be discussed in more detail below.

[0014] In both variants, a further development of the coupling according to the invention provides that in the area of ​​the connection, a sealing chamber with defined dimensions is formed on the coupling side between the first inner pipe element and the second inner pipe element, in which a seal is received.

[0015] By providing such a sealing chamber with defined dimensions, at least in the axial direction, improved sealing against leakage of the process medium into an area between the pipelines can be achieved reliably and reproducibly.

[0016] In both variants, a further development of the coupling according to the invention provides that the sealing chamber is formed by arranging the two inner pipe elements in a block configuration. This does not have to be done directly, but can be achieved by interposing further (pipe) elements.

[0017] By arranging the two inner pipe elements flush, the sealing effect can be adjusted precisely, reliably and reproducibly: As soon as the torque required to tighten the connection increases significantly, the two inner pipe elements are flush against each other, and the intended seal is achieved.

[0018] In both variants, a further development of the coupling according to the invention provides that the sealing chamber is formed between an end termination element of the coupling plug and an end termination element of the coupling socket, preferably as a circumferential recess in the end termination element of the coupling socket or the coupling plug.

[0019] These end elements are regularly designed in the form of turned parts, so that the required recesses for creating the sealing chamber can be produced easily and reliably, and the sealing chamber also has the required stability.

[0020] In both variants, a further development of the coupling according to the invention provides that an axial dimension of the sealing chamber is limited by an axial excess of an axial projection of the terminal end element of the coupling plug beyond the remaining terminal end element of the coupling plug, or by an axial excess of an axial projection of the terminal end element of the coupling bushing beyond the remaining terminal end element of the coupling bushing. The aforementioned end elements serve in particular to connect the inner, media-carrying pipe elements.

[0021] By means of the aforementioned oversize or projection, the mechanical contact of the two inner pipe elements (“on the block”) mentioned above can be reliably and reproducibly established without affecting more sensitive components of the arrangement (e.g. sealing elements).

[0022] In both variants, a further development of the coupling according to the invention provides that the drive element is designed to be torsionally stable, in particular using a grooved membrane disc or as an additional pipe element, which is preferably designed at least partially as a corrugated hose, in particular as an annular corrugated hose, most preferably as a bellows, and which does not need to be fluid-tight.

[0023] This enables the transmission of a rotational movement exerted on the drive element from the outside about a common longitudinal axis of the pipe elements and can at the same time ensure good thermal decoupling of the hot end and cold end by increasing the thermal resistance.

[0024] In particular, in a first variant of the coupling according to the invention, it is further provided that the engagement structures are designed as complementary thread structures. are designed preferably as an internal thread on the drive element and as an external thread on the coupling bushing, most preferably on the second inner pipe element, or vice versa.

[0025] In this way, the intended rotational movement exerted on the drive element from the outside about a common longitudinal axis of the pipe elements can be safely and precisely converted into the desired relative movement in the axial direction.

[0026] In particular, in the first variant of the coupling according to the invention, it is further provided that after the first engagement structure and the second engagement structure have been brought into contact, an axial overlap area exists in which a screw connection is formed between the drive element and the coupling bushing. The coupling plug engages axially with a radial engagement projection in the overlap area between the drive element and the second inner pipe element, so that when the screw connection is tightened, the coupling plug is moved or can be moved axially in the direction of the second inner pipe element (i.e., in the direction of the coupling bushing).

[0027] This represents a preferred embodiment for effecting the desired relative movement in the axial direction. The elements plug, bushing, and drive element are fundamentally designed or arranged in a torsion-free manner relative to each other.

[0028] In particular, in the first variant of the coupling according to the invention, it is further provided that the aforementioned drive projection is designed as a retaining ring or snap ring, which is partially arranged in a circumferential groove on the coupling plug.

[0029] Such a design is particularly easy and inexpensive to manufacture, which has a positive effect on the overall manufacturing costs of the coupling.

[0030] In particular, in the first embodiment of the coupling according to the invention, it is further provided that the drive element extends axially from a “hot end”, where the first outer pipe element and the second outer pipe element are connected to each other, to a “cold end”, where the first inner pipe element and the second inner pipe element are connected to each other, wherein the drive element is preferably arranged radially between the coupling socket and the coupling plug. In the first embodiment, the “hot end” and the “cold end” are not regularly located in a common axial position.

[0031] The drive element does not need to be fluid-tight, but can have holes, openings or the like, as long as it remains torsionally stable. This ensures that Material and weight are saved, and thermal conductivity may be reduced, which can bring corresponding advantages.

[0032] In this way, a kind of “remote control” of the connection can be realized, whereby a targeted seal can be achieved at the (poorly or not at all accessible) cold end by applying external force in the area of ​​the easily accessible warm end.

[0033] In particular, in the first variant of the coupling according to the invention, it is further provided that the first outer tube element is designed as a structured tube element at least in a partial section and has an outer contour in that partial section that deviates from a smooth cylindrical shape. Preferably, the first outer tube element can have a number of annular bulges in that partial section, or the first outer tube element can have a number of distinct local bulges in that partial section, or the first outer tube element can have a honeycomb-shaped configuration of its outer contour in that partial section.

[0034] Accordingly, in the aforementioned further development of the first variant, it is proposed to design the insulation pipe (i.e., the outer pipe element) of the connector (i.e., the first outer pipe element) of a Johnston coupling with a structured outer contour, i.e., with an outer contour that deviates from a smooth cylindrical shape, in order to counteract buckling and thus to be able to make the insulation pipe thinner-walled than in the prior art. This limits heat conduction and reduces heat input. In addition, the structuring also contributes to locally stabilizing the gas cushion mentioned, so that the effect of the media on the warm sealing element can be efficiently prevented.

[0035] In particular, the design of the aforementioned insulation pipe as a so-called “bulped pipe” with corrugated bulges is advantageous here, since the corrugated cross-section of the structuring significantly increases the resistance to bulging.

[0036] Alternatively or additionally, the drive element can also be designed, at least in a partial section, as a structured tube element (preferably as a so-called "bulged pipe"). The advantage of the "bulged pipe" or other structured tube elements is increased resistance to bulging, and they perform a guiding function when the coupling is assembled. Since, within the scope of the present invention, the insulation pipe of the connector is not pressurized because the seal at the cold end effectively seals, the aforementioned guiding function can also be performed by the drive element. The advantages of a structured insulation pipe discussed below therefore also apply, analogously, to the drive element, provided it is appropriately designed.

[0037] Furthermore, in this way a circumferential joining gap to the insulation pipe (the inner pipe element) of the socket (i.e., the second inner pipe element) or to the drive element can be locally reduced. With appropriate design, this creates circumferential chambers between the two insulation pipes or between the insulation pipe of the connector and the drive element of the connected coupling, which are separated from each other only by narrow annular gaps. The annular gaps can be made so small that the liquid process medium is forced to undergo a phase change in the gap area due to the heat input via the insulation pipes and the drive element, thereby forming a localized or even several localized gas cushions, which allows the coupling to be positioned independently of the direction of gravity.

[0038] An additional advantage is that the wave crests of the “bulped pipe” act as a guide during coupling and effectively reduce the friction between the plug and the drive element.

[0039] The required roundness of the pipe elements (insulation pipes) and the drive element can be achieved by manufacturing them by means of a forming process (calibration), e.g. by internal high-pressure forming or most preferably by bellows pressing.

[0040] The following embodiments have proven to be particularly advantageous in this context (i.e., in the first variant):

[0041] One embodiment of the coupling according to the invention provides that the outer pipe element of the coupling plug (i.e., the first outer pipe element) has a number of annular bulges in the section. Preferably, this number is a plurality of bulges. This allows several of the aforementioned narrow annular gaps to be created, which greatly improves the insulating effect.

[0042] One embodiment of the coupling according to the invention provides that the ridges are identically designed. This contributes to a further improved insulating effect and allows the advantageous use of a smooth tube as an outer insulation pipe or as a drive element.

[0043] One embodiment of the coupling according to the invention provides that the bulges, in a section along a longitudinal axis of the coupling, have an axially symmetrical design with respect to an axis perpendicular to the longitudinal axis through a vertex of a respective bulge. This has proven to be particularly advantageous for reasons of stability.

[0044] One embodiment of the coupling according to the invention provides that the bulges form a continuous direction towards the inner tube element of the The coupling plug (i.e., the second inner pipe element) has a curved path in the direction of the drive element. This further contributes to stabilization and is also advantageous with regard to the previously mentioned reduction in friction.

[0045] Another embodiment of the coupling according to the invention provides that the outer pipe element of the coupling plug has a number of distinct local bulges in the section, which are preferably not completely continuous. In a specific embodiment, this results in a so-called "dimpled pipe", i.e., a pipe element with a dimple structure, similar to a golf ball. Such an embodiment is also advantageous for reasons of stability, which allows for less material usage and reduced heat conduction.

[0046] Yet another embodiment of the coupling according to the invention provides that the local ridges are arranged in a regular pattern. According to the applicant's findings, this has proven advantageous because the stability is thus increased uniformly. The joining properties are also correspondingly improved.

[0047] Yet another embodiment of the coupling according to the invention provides that the outer tube element of the coupling plug has a honeycomb-shaped design of its outer contour in that section. Such a structure is also advantageous for reasons of stability.

[0048] In a further development of this embodiment of the coupling according to the invention, it can be provided that the honeycomb-shaped design has hexagonal ridges and depressions enclosed by these ridges, or vice versa. This allows comparable advantages to be achieved as with the aforementioned ring-shaped wave structures.

[0049] In another embodiment of the coupling according to the invention, the outer tubular element of the coupling plug rests against the drive element on the inside, in particular with its ridges according to one of the previously described embodiments. This makes it possible to form the aforementioned separate area or circumferential ridges between which thermally insulating gas cushions can form, further improving the efficiency of the coupling.

[0050] In another embodiment of the coupling according to the invention, it is further provided that the outer tubular element of the coupling plug is axially pre-tensioned, particularly during the actual coupling process, in order to specifically form the bulges radially outwards and to close gaps, in particular annular gaps, between the outer tubular element of the coupling plug and the drive element, or at least to make them as narrow as possible. The advantages associated with this have already been mentioned above.

[0051] In another embodiment of the coupling according to the invention, it is further provided that a local sealing element insert is arranged between the outer tube element of the coupling plug and the drive element, at least in the area of ​​a subset of the bulges, preferably in all bulges. This further improves the closing of the (ring) gap.

[0052] In a further embodiment of this coupling according to the invention, it is also provided that the sealing element insert consists of a metal, preferably indium. Metallic seals are generally resistant to high vacuum and can withstand high loads. In particular, the choice of indium can ensure that no additional increased thermal conductivity occurs, as would be the case, for example, with the use of copper.

[0053] In another embodiment of the coupling according to the invention, it is further provided that at least the outer tube element of the coupling plug is a cost-effective longitudinally welded tube, which has preferably been modified by forming, such as preferably internal high-pressure forming or most preferably by bellows pressing. These processes are known to those skilled in the art. This results in improved roundness and, at the same time, improved sealing, as has already been mentioned.

[0054] In another embodiment of the coupling according to the invention, it is further provided that at least the outer tube element of the coupling plug has a variable wall thickness in the axial and / or circumferential direction.

[0055] The term “variable wall thickness” means that the wall thickness is not constant, but assumes different values ​​in the axial direction (along the longitudinal axis) and / or in the circumferential direction. This fact can be used selectively during forming. In addition, the applicant has found that such a change in wall thickness also increases the stability of the insulation pipe and leads to a reduced material usage (with lower thermal conductivity).

[0056] In yet another embodiment of the coupling according to the invention, the outer tubular element of the coupling plug is stabilized by additional elements, such as stabilizing rings, which are preferably positively locked, most preferably materially bonded. These additional elements are preferably arranged at selected positions along the outer tubular element of the coupling plug. They can help to selectively influence or mitigate its buckling behavior. In the warm area, they preferably consist of plastic, preferably fiber-reinforced, most preferably G10, and in the cold area of ​​steel, preferably austenitic steel, which can be materially bonded / fixed. To maximize the advantage of the To achieve the use of identical parts, the design can also be limited to only one (identical) construction type.

[0057] In this way, the present invention, particularly in the first variant, achieves the following further advantages over the prior art: lightweight construction with reduced material usage, increased robustness against buckling, enabling installation in any orientation, and reduced heat input. Due to the improved thermal decoupling, a shorter overall length than that achieved according to the prior art can also be realized.

[0058] Another further development of the coupling according to the invention of the first variant provides that the section in which the first outer pipe element is structured coincides axially with a section of the drive element in which the drive element is designed as a smooth tube, and vice versa.

[0059] In this way, the first external pipe element and the drive element are geometrically completed, which can contribute to a reduced construction size.

[0060] Another further development of the coupling according to the invention of the first variant provides that the drive element has a radial projection accessible from the outside, preferably with a regular hexagonal shape.

[0061] In this way, the required rotational action can be achieved as simply as possible and with standard tools.

[0062] Another further development of the coupling according to the invention of the first variant provides that the drive element is connected or connectable to the coupling plug via the radial projection, preferably by means of a first clamp.

[0063] This represents a simple and well-established connection method that can be implemented without significant (cost) effort.

[0064] Another further development of the coupling according to the invention of the first variant provides that the drive element has an outer threaded section.

[0065] This threaded section allows the attachment of further components of the coupling, which will be discussed below.

[0066] Another further development of the coupling according to the invention of the first variant provides that a screw-on part is screwed or can be screwed onto the threaded section, in particular in the form of a lock nut, preferably up to the coupling bushing (as a pressure stop).

[0067] In this way, a simple way is created to fix the coupling bushing and screw-on part (and via this also the coupling plug) axially relative to each other and to create a tolerance compensation.

[0068] Another further development of the coupling according to the invention of the first variant provides that the drive element is connected or connectable to the coupling bushing via the screw-on part, preferably by means of a second clamp, and acts as a tie rod.

[0069] This in turn represents a simple and well-established connection option that can be implemented without significant (cost) effort.

[0070] In the following, certain advantageous further developments of the already mentioned second variant of the inventive coupling will be described in more detail, which are based on the solution known from DE 10 2022 110 880 A1:

[0071] A further development of the inventive coupling of the second variant provides that the drive element has a first, ring-shaped outer connecting part and a second, ring-shaped inner connecting part, which are arranged concentrically and together form the first engagement structure and which are connected in a torsionally rigid manner by means of a radially extending first grooved membrane disk. The first grooved membrane disk can, in particular, be bonded to the two connecting parts by means of a material bond.

[0072] The term “torsionally rigid” means here and in the following that torques can be transmitted by means of the connection in question (or a correspondingly designed component, e.g. the grooved membrane disc mentioned).

[0073] The grooved membrane disc ensures effective thermal decoupling of the two connecting parts without requiring more space in the axial direction. The concentric connecting parts can contribute to achieving a particularly good and secure connection. In addition, the grooved membrane disc enables the transmission of torque, which will be discussed in more detail below.

[0074] In the second variant, the “warm end” and the “cold end” are regularly located at least approximately in a common axial position.

[0075] A further development of the coupling according to the invention of the second variant provides that the coupling bushing has first connection structures on the second outer pipe element and second connection structures on the second inner pipe element, which together form the second engagement structure.

[0076] In this way, together with the above-mentioned concentric connecting parts, a particularly good and secure connection can be created.

[0077] A further development of the coupling according to the invention of the second variant provides that the first engagement structure and the second engagement structure are designed in the manner of a bayonet fitting and interact accordingly. The first connection structures can preferably be connected to the first The connecting part and the second connecting structures interact with the second connecting part.

[0078] Bayonet fittings are known to those skilled in the art. In the present context, the bayonet fitting advantageously ensures that the intended axial movement can be achieved with only a small (i.e., limited in the circumferential direction) rotational movement.

[0079] A further development of the coupling according to the invention of the second variant provides that the coupling bushing has a radially extending second grooved membrane disc which connects the second outer pipe element and the second inner pipe element and which is arranged in a form-fitting manner to the first grooved membrane disc.

[0080] In this context, the term “form-fit” means that the first grooved diaphragm disc and the second grooved diaphragm disc lie congruently on top of each other (i.e., their wave crests and troughs can interlock) when the coupling is closed.

[0081] The second grooved membrane disc can be specifically designed to seal a radial free space between the second outer pipe element and the second inner pipe element in the area of ​​the coupling bushing against the environment and thus make it evacuatable, which can improve the thermal insulation.

[0082] A further development of the coupling according to the invention of the second variant provides that the second grooved diaphragm disc is axially supported on the rear side.

[0083] This increases the resistance to ambient pressure after evacuation. “Rear” refers to the side facing away from the coupling point.

[0084] A further development of the coupling according to the invention of the second variant provides that the first grooved diaphragm disc and the second grooved diaphragm disc have different dimensions in the radial direction.

[0085] This allows for different (radial) dimensions of the pipe elements or connecting parts in the area of ​​the plug and socket to be taken into account.

[0086] A further development of the coupling according to the invention of the second variant provides that the coupling plug has a radially extending third grooved membrane disc which connects the first outer pipe element and the first inner pipe element and which is arranged in a form-fitting manner to the first grooved membrane disc and the second grooved membrane disc.

[0087] In this context, the term “form-fit” means that the first grooved membrane disc, the second grooved membrane disc and the third The grooved membrane discs lie congruently on top of each other (i.e., their wave crests and valleys can interlock), especially when the clutch is closed.

[0088] The third grooved membrane disc can be specifically designed to seal a radial free space between the first outer pipe element and the first inner pipe element in the area of ​​the coupling plug from the environment and thus make it evacuatable, which can improve the thermal insulation.

[0089] A further development of the coupling according to the invention of the second variant provides that the third grooved diaphragm disc is axially supported on its rear side. “Rear side” again refers to the side facing away from the coupling point.

[0090] This can increase the resistance to ambient pressure after evacuation.

[0091] A further development of the coupling according to the invention of the second variant provides that the first grooved diaphragm disc and the third grooved diaphragm disc have the same dimensions in the radial direction.

[0092] This ensures improved stability and is possible because both of the aforementioned grooved membrane discs are arranged on the same component (the connector).

[0093] In a composite state of the coupling, the first grooved diaphragm disc is preferably arranged between the second and the third grooved diaphragm disc, the latter two being axially supported from the outside.

[0094] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing. [Fig. 1] shows a coupling according to the invention according to the first variant in its individual parts; [Fig.2] shows the essential components of the coupling from Figure 1 in longitudinal section; [Fig.3] shows the coupling from Figure 1 in longitudinal section and in the assembled state; [Fig.4] shows a coupling according to the invention according to the second variant in longitudinal section and in an open state; [Fig.5] shows the coupling from Figure 4 in its closed state; [Fig.6] shows a detailed view of the coupling bushing according to the design in Figure 4; [Fig.7] shows a detailed view of the coupling plug according to the design in Figure 4; [Fig.8] shows a cutaway partial view of a coupling according to the invention in a different embodiment.

[0095] In all figures, the same reference numerals denote identical or at least equivalently functioning elements. The terms “pipe element” and “pipeline element” are used synonymously throughout.

[0096] Figure 1 shows an exploded view of a coupling 1 of the first variant according to the invention with longitudinal axis L. Reference numeral 2 designates the coupling plug (plug), and reference numeral 3 designates the coupling socket (socket). A tubular drive element 4 is arranged between them, which, further below, is also provided with reference numeral 36. The coupling 1 also comprises two clamps 5, 6, two centering elements 7, 8, a screw-on part 9, and two seals (sealing rings) 10, 11. All these elements and their interaction will be discussed in more detail below.

[0097] According to Figure 2, partial figure a), hereinafter referred to as Figure 2a), the connector 2 comprises two coaxial tube elements extending from its front insertion end 12, namely an inner (media-carrying) tube element 13 and an outer tube element 14. The outer tube element 14 is partially designed as a structured tube element and accordingly has an outer contour that deviates from a smooth cylindrical shape over most of its length. Specifically, it is structured over most of its length as a "bulbed pipe" with several identical annular bulges 15, of which only one is explicitly designated. This allows the tube element 14 to be made lighter and thinner while maintaining the same or even improved (pressure) stability. Preferably the outer tube element 14 of the coupling plug 2 is produced by forming, such as preferably internal high-pressure forming or most preferably bellows pressing.

[0098] At one end 16 (the so-called “warm end”), the outer tube element 14 is radially expanded and has no bulges in this area. In a transition area between the bulges 15 and the expanded end 16, an approximately triangular-shaped elevation 17 is provided on the outside, which will be discussed in more detail later.

[0099] At the other end 18 (the so-called “cold end”), a first end element 19 is arranged, which fluid-tightly connects the inner pipe element 13 and the outer pipe element 14, preferably by a material bond. The end element 19 has a front end face 19a with an inner, circumferential projection 19b. A retaining projection 21 in the form of a locking ring is arranged in a circumferential groove 20 of the end element 19. Reference numeral 22 shows a multi-layer insulation (MLI), i.e., a multi-layer insulation arranged between the inner pipe element 13 and the outer pipe element 14. Multilayer insulation is generally in the form of a multilayered, highly (radiation-)reflective film or the like, which is known to those skilled in the art.

[0100] According to Figure 2, partial figure b), the socket 3 also comprises two coaxial tube elements, namely an inner tube element 23 and an outer tube element 24, between which a multi-layer insulation (MLI), i.e., a multilayer insulation 25, is arranged. The two coaxial tube elements 23, 24 of the socket 3 are fluid-tightly connected to each other at one end 26 (the "hot end" according to reference numeral 16) via a second termination element 27, preferably by a material bond. The second termination element 27 has a shape at reference numeral 28 that is mirror-symmetrical to the triangular protrusion 17 of the plug 2.The inner tube element 23 of the socket 3 is tapered in cross-section at its free end (right in Figure 2b)) and has a fluid-conducting (media-carrying) tube extension 29 connected to the rest of the inner tube element 23 of the socket 3. The diameter of this extension is adapted to that of the inner (media-carrying) tube element 13 of the plug 2. The tube extension 29 and the inner tube element 13 of the plug 2 are connected as fluid-tight as possible by means of a seal (not shown in Figure 2), which will be described in more detail below.

[0101] In a transition area 30 from the inner tube element 23 to the tube extension 29, the bushing 3 has an annular reducing part 31, which is preferably formed in a material-bonded manner with the inner tube element 23 and integrally with the tube extension 29 and which has an axial projection 32 with external thread 33, a (surface-) structured radial surface 34 and a recess 35 in the transition area between radial surface 34 and tube extension 29.

[0102] Figure 2, partial figure c), in short: Figure 2c), shows the additional drive element 36, which is designated by reference numeral 4 in Figure 1 and which is to be arranged radially between plug 2 and socket 3, as will be shown more clearly below with reference to Figure 3. The drive element 36 is tubular in shape overall and has a smooth cylindrical section 37 and an annular corrugated section 38. The smooth cylindrical section 37 corresponds in its longitudinal dimension to the structured section of the tubular element 14, while the annular corrugated section 38 corresponds in its longitudinal dimension to the smooth cylindrical "remainder" of the tubular element 14. A ring part 39 with an internal thread 40 is connected (materially interlocked) to the end of the annular corrugated section 38.At the other end, the drive element 36 has a chamfered radial projection 41 (preferably with an external hexagonal contour), an external thread 42, and two circumferential grooves 43, 44, which serve to receive the sealing rings 10, 11 from Figure 1.

[0103] Figure 3 shows the assembled coupling 1. For the sake of clarity, not all elements are labelled again. To tightly connect plug 2 and socket 3 at the cold end 18, the drive element 36 is inserted into the socket 3, and plug 2 is in turn inserted into the drive element 36. When the drive element 36 is now rotated about the longitudinal axis L and screwed onto the external thread 33 (see Figure 2) of the socket 3 with its internal thread 40 (see Figure 2), which corresponds to embodiment a) according to the invention, it takes the plug 2 with it in the axial direction due to the retaining ring 21 (see Figure 2) until the plug 2 abuts with its projection 19b at the end of the recess 35 of the socket 3. In other words, when the drive element 36 reaches the retaining ring 21, a fixed connection between the drive element 36 and the connector 2 is formed in an axial direction. Then, respectively,A sealing chamber 45 with a well-defined (axial) dimension A is formed between the contact surface 19a of the plug 2 and the radial surface 34 of the socket 3. A seal (sealing ring) 46 is inserted into this chamber, ensuring a secure seal at the cold end 18, while the drive element 36 can be conveniently (remotely) operated from the warm end 16.

[0104] To secure the connection at the warm end 16, the plug 2 has the aforementioned, approximately triangular or conical-shaped elevation 17 on its outer surface (see Figure 2), against which the drive element 36 with its projection 41 (see Figure 2) fits. It is secured in this area by means of the clamp 5. Furthermore, the screw-on part 9 is screwed onto the external thread 42 of the drive element 36 up to the projection 28 of the socket 3, similar to a lock nut. It is also secured here by means of the clamp 6.

[0105] In the coupling 1 shown, after the first engagement structure (in particular the internal thread 40 of the drive element 36, see Figure 2) and the second engagement structure (in particular the external thread 33 of the bushing 3, see Figure 2) have been engaged, an axial overlap area is formed in which a screw connection is formed between the drive element 36 and the coupling bushing 3. The coupling plug 2 engages axially with its radial engagement projection 21 (see Figure 2) in this overlap area between the drive element 36 and the second inner pipe element 23 or the reducing part 31, so that the coupling plug 2 is movable, or is moved, axially in the direction of the second inner pipe element 23 or the radial surface 34 of the reducing part 31 when the screw connection is tightened.

[0106] The clamp (V-board clamp) 5 serves to detachably connect plug 2 and drive element 4, 36, or the clamp (V-board clamp) 6 serves to detachably Connecting drive element 4 or 36 and socket 3. Reference numerals 7 and 8 denote the centering or stabilizing elements already mentioned above. These stabilizing elements 7, 8 ensure that the inner tube element 13 is centered within the outer tube element 14 in the area of ​​the extended end of the plug 2 or the tube extension 29 within the outer tube element 24; they are preferably made of a poorly heat-conducting material that is vacuum-compatible (no outgassing) and preferably consists of a fiber-reinforced plastic, most preferably of glass-fiber-reinforced plastic, such as G10.

[0107] Figure 3 shows – as already mentioned – the connected state of the coupling 1. In this state, the coupling bushing 3 and the coupling plug 2 are detachably connected to each other by a first connection located at the hot end 16 in the area of ​​their outer tube elements 14 and 24, respectively (by means of the clamps 5, 6 and with the drive element 4 or 36 interposed). Furthermore, in the connected state, a joining gap at the other, cold end 18 between the coupling bushing 3 and the coupling plug 2 in the area of ​​their inner tube elements 13 and 23, 29, respectively, is sealed by the seal 46.

[0108] As can be seen from Figure 3, the bulges 6 of the tube element 14 have a symmetrical shape in a section along the longitudinal axis L of the coupling 1 with respect to a plane perpendicular to the longitudinal axis L through a vertex (not shown) of a bulge 15. In addition, the bulges 15 have a continuously curved shape in the direction of the inner tube element 13 of the coupling plug 2, i.e. convex shape with respect to the longitudinal axis L.

[0109] The outer tubular element 14 of the coupling plug 2 rests with its bulges 15 on the inside of the drive element 36 in its smooth cylindrical section. To achieve this, the outer tubular element 14 of the coupling plug 2 can be axially pre-tensioned during the coupling process, so that the bulges 15 in particular are formed radially outwards to close gaps, especially annular gaps, between the outer tubular element 14 of the coupling plug 2 and the drive element 36. In this way, separate annular cavities 47 are formed along the coupling 1, which ensure that as little cryogenic fluid as possible reaches the "warm" sealing elements 10 and damages them. In any case, any remaining annular gaps between elements 14 and 36 ensure that any cryogenic fluid that has penetrated evaporates and forms efficient insulating gas cushions to prevent further heat input from the outside.

[0110] Although this is not shown in the figures, at least in the area of ​​a subnumber of the bulges 15, a local sealing element insert can be additionally arranged between the outer tube element 14 of the coupling plug 2 and the drive element 36, which sealing element insert consists in particular of a metal, preferably indium.

[0111] Figures 4 to 7 show an alternative embodiment of the coupling 1 which differs significantly in the design of the “warm” connection and the drive element from the variant according to Figures 1 to 3.

[0112] Figure 4 shows the coupling 1' in its open state. Essentially, only the most important differences from the first embodiment are discussed in detail.

[0113] The coupling 1' has a drive element 48 in the area of ​​the plug 2, which has a first, annular outer connecting part 49 with a radial projection 49a, preferably with an outer hexagonal contour, and a second, annular inner connecting part 50, which are arranged concentrically and together form a first, plug-side engagement structure, which is specifically designed in the manner of a bayonet fitting. The connecting parts 49, 50 are connected by means of a radially extending first grooved membrane disc 51. This first grooved membrane disc 51 is bonded to the two connecting parts 49, 50. It enables torques to be transmitted from the first connecting part 49 to the second connecting part 50 by means of the drive element 48 and, due to its effective length in the radial direction, ensures a relatively high thermal resistance.The outer connecting part 49 is attached via a retaining ring 49b to a multi-stepped pipe section 14a, which represents an axial extension (bonded) of the first outer pipe element 14.

[0114] Accordingly, in the coupling 1 ' according to Figure 4, it is provided that the coupling bushing 3 has first connection structures 52 on the second outer pipe element (at reference numeral 24, only indicated; cf. Figure 5) and second connection structures 53 on the second inner pipe element 23, which together form a second, bushing-side engagement structure.

[0115] As already mentioned, in this variant the first, plug-side engagement structure and the second, socket-side engagement structure are designed in the manner of a bayonet fitting and interact accordingly, with the first connection structures 52 interacting with the first connection part 49 and the second connection structures 53 interacting with the second connection part 50. Bayonet fittings are known to those skilled in the art, so the exact design need not be discussed here. Closing the bayonet fitting by a corresponding (relative) rotational movement of plug 2 and socket 3 does not ensure not only for a secure locking of the coupling 1 ', but also causes an axial relative movement of plug 2 and socket 3 for sealing purposes, which will be discussed in more detail below.

[0116] First, it should be noted that in the coupling 1, the coupling socket 3 has a radially extending second grooved membrane disc 54, which connects the second outer pipe element 24 and the second inner pipe element 23 via the connecting structures 52, 53, so that an intermediate space or free space 55 can be evacuated, and which is arranged in a form-fitting manner to the first grooved membrane disc 51, which in this case means that the grooved membrane discs 51 and 54 interlock with their wave troughs and crests when plug 2 and socket 3 are aligned coaxially along the longitudinal axis and brought together axially (see below, Figure 5).

[0117] According to Figure 4, in the connector 2, the first outer tube element 14 and also the first inner tube element 13 are largely designed as an annular corrugated hose. Between them is an intermediate space or free space 56, the MLI 22, and a braided hose 57, which surrounds the inner tube element 13 for stabilization. The free space 56 can be evacuated via a connection nozzle 57. Reference numeral 58 designates an adsorber.

[0118] For this purpose, the coupling 1' or the coupling plug 2 also has a radially extending third grooved diaphragm disc 59, which connects the first outer pipe element 14 in the area of ​​the extension pipe section 14a and the first inner pipe element 13 in the area of ​​the end element 19 in a material-fit manner, so that the space 56 can be evacuated. The third grooved diaphragm disc 59 is arranged in a form-fit relationship specifically to the first grooved diaphragm disc 51 and (when the coupling 1' is closed, see Figure 5) also to the second grooved diaphragm disc 54, as defined above. In Figure 4, the grooved diaphragm discs 51 and 59 are already in a form-fit relationship to one another, so that they are no longer recognizable as separate entities.

[0119] In order to better withstand the ambient pressure during evacuation of the intermediate spaces 55, 56, the second grooved membrane disk 54 and the third grooved membrane disk 59 are each axially supported on their rear side, for which at least one corresponding support element 60, 61 is provided, as shown.

[0120] While the first grooved membrane disk 51 and the second grooved membrane disk 54 have different dimensions in the radial direction, preferably the first grooved membrane disk 51 and the third grooved membrane disk 59 have the same dimensions in the radial direction, as shown.

[0121] The so-called “cold end” 18 is arranged inside according to the embodiment shown in Figure 4. The already mentioned end element 19 is also arranged there, which The inner pipe element 13 and the outer pipe element 14, including the extension 14a (via the grooved membrane disc 59), are fluid-tight and materially bonded together. The end element 19 has a front face 19a with an inner, circumferential projection 19b. Reference numeral 46 again denotes a seal. A retaining ring 21 is arranged in a circumferential groove 20 of the end element 19, which, in conjunction with a spring 62 and a circumferential projection 63, ensures that the connecting part 50 is securely held on the end element 19.

[0122] Analogous to the design of the socket 3 according to Figure 2, Figure 4 also shows a ring part 31 with radial surface 34 and recess 35 to provide a sealing chamber of defined (axial) dimensions in conjunction with the plug 2 when the end element 19 and the ring part 31 with the projection 19b in the area of ​​the recess 35 come into contact. This is illustrated in Figure 5.

[0123] Figure 5 shows the coupling 1' from Figure 4 in its closed state. For the sake of clarity, not all elements are explicitly labelled again (see Figure 4). The engagement structures interact in a bayonet-like manner, as explained in detail above. All three grooved diaphragm discs 51, 54, 59 then lie positively against each other. The sealing chamber 45 has a defined dimension A in the axial direction, as described above with reference to Figure 3. Here, too, the connection is tightened at the cold end 18 by applying a torque to a drive element 48 at the warm end 16, specifically by acting on element 49 (at reference numeral 49a) to close the bayonet fitting and simultaneously cause an axial relative movement, especially of parts 19 and 31, which creates the described seal at the cold end 18.

[0124] Figure 6 shows a perspective detail view of the socket 3 and illustrates the possible design of the bayonet-type connecting structures 52, 53 as well as the design of the grooved membrane disk 54.

[0125] Figure 7 shows a perspective detail view of the connector 2 and illustrates the possible configuration of the complementary bayonet-type connection structures on the connecting parts 49, 50, as well as the configuration of the relevant grooved membrane disk 51, which is used for torque transmission. The torque acts accordingly at reference numeral 49a. For this purpose, element 49 specifically has recesses 49c. Alternatively, a configuration with a hexagonal contour is also possible in this area.

[0126] Figure 8 shows a modification, partially different from the embodiment shown in Figures 1 to 3, according to the embodiment b) according to the invention. Here, only the essential differences from the embodiment already described according to Figures 1 to 3 will be discussed in more detail:

[0127] As shown in Figure 8, the external thread 40, which forms part of the described engagement structure, is not located on the socket 3, but on the plug 2. A ring part 39 with an internal thread 40 is connected (materially bonded) to the ring-corrugated section 36 of the drive element 36. In contrast, the retaining ring 21 is not located on the plug 2, but between the ring part 39 and the reducing part (terminating element) 31 of the socket 3.

[0128] In this way, the socket 3 and the drive element 36 can be pre-assembled. The described axial relative movement of the coupling plug 2 and the coupling socket 3 after the engagement of the first engagement structure and the second engagement structure can also be effected here by a rotational movement about a common longitudinal axis L of the pipe elements exerted on the drive element 36 from the outside, thereby creating or making possible a fluid-tight connection.

[0129] Figure 8 also shows that, unlike the embodiment shown in Figures 1 to 3, the connector 2 (specifically the insulation tube "male", element 14) is not designed as a bulbed pipe, but rather the drive element 36 is in a partial section (to the left of the corrugated section 38). As already mentioned, a significant advantage of the bulbed pipe is its increased resistance to bulbing. However, in the present invention, the insulation pipe 14 is not pressurized, since the cold seal 46 effectively seals. Therefore, the guide bulbs can also be located in the drive element 36. This also applies in principle to the embodiment according to Figures 1 to 3.

Claims

Demands [Revendication 1] Coupling (1, 1') for cryogenic conduits with a coupling socket (3) and a coupling plug (2), wherein: the coupling plug (2) has a first inner, media-carrying pipe element (13) and a first outer pipe element (14) which coaxially surrounds the first inner pipe element (13) at a radial distance, between which first pipe elements (13, 14) an evacuable first free space (56) is formed; the coupling socket (3) has a second inner pipe element (23, 29) and a second outer pipe element (24) which coaxially surrounds the second inner pipe element (23, 29) at a radial distance, between which second pipe elements (23, 24) an evacuable second free space (55) is formed; the first inner piping element (13) is detachably connected or connectable to the second inner piping element (23, 29);the first outer pipe element (14) is detachably connected or connectable to the second outer pipe element (24); characterized by a drive element (4, 36; 48) that is connected or connectable to the coupling plug (2) and that a) has a first engagement structure that is complementary to a second engagement structure on the coupling socket (3), or that b) has a first engagement structure that is complementary to a second engagement structure on the coupling plug (2); wherein, after engagement of the first engagement structure and the second engagement structure by means of an external force applied to the drive element (4, 36;48) The rotational movement exerted about a common longitudinal axis (L) of the pipe elements (13, 14, 23, 24) causes or can cause an axial relative movement of the coupling plug (2) and the coupling socket (3), whereby a fluid-tight connection is created or can be created between the first inner pipe element (13) and the second inner pipe element (23, 29). [Revendication 2] Coupling (1, 1') according to claim 1, wherein in the area of ​​the connection there is a connection on the end face between the first a sealing chamber (45) with defined dimensions (A) is formed between the inner pipe element (13) and the second inner pipe element (23, 29), in which a seal (46) is received. [Revendication 3] Coupling (1, 1') according to claim 2, wherein the sealing chamber (45) is formed by the two inner pipe elements (13, 23) being arranged in a block. [Revendication 4] Coupling (1, 1') according to claim 2 or 3, wherein the sealing chamber (45) is formed between an end termination element (19) of the coupling plug (2) and an end termination element (29, 31) of the coupling socket (3), preferably as a circumferential recess in the end termination element of the coupling socket (3) or of the coupling plug (2). [Revendication 5] Coupling (1, 1') according to claim 4, wherein an axial dimension of the sealing chamber (45) is limited by an axial excess of an axial projection (19b) of the terminal end element (19) of the coupling plug (2) beyond the remaining terminal end element (19) of the coupling plug (2) or by an axial excess of an axial projection of the terminal end element of the coupling socket (3) beyond the remaining terminal end element of the coupling socket (3). [Revendication 6] Coupling (1) according to one of the preceding claims, wherein the drive element (4, 36; 48) is designed to be torsionally stable, in particular using a grooved membrane disc (51) or as an additional pipe element (4, 36) which is preferably designed at least partially as a corrugated hose, most preferably as an annular corrugated hose (38) or bellows. [Revendication 7] Coupling (1) according to one of the preceding claims, wherein the engagement structures are designed as complementary thread structures, preferably as internal threads (40) on the drive element (4, 36) and as external threads (33) on the coupling bushing (3), most preferably on the second inner pipe element (23, 29), or vice versa. [Revendication 8] Coupling (1) according to claim 7, in which an axial overlap area exists after the first engagement structure and the second engagement structure have been brought into engagement, in a screw connection is formed between the drive element (4, 36) and the coupling bushing (3), wherein the coupling plug (2) engages axially between the drive element (4, 36) and the second inner pipe element (23, 29) in the overlap area with a radial engagement projection (21), so that the coupling plug (2) is movable axially in the direction of the second inner pipe element (23, 29) when the screw connection is tightened. [Revendication 9] Coupling (1) according to claim 8, wherein the drive projection (21) is designed as a retaining ring or snap ring, which is partially arranged in a circumferential groove (20) on the coupling plug (2). [Revendication 10] Coupling (1) according to one of claims 7 to 9, wherein the drive element (4, 36) extends axially from a “hot end” (16, 26) in which the first outer pipe element (14) and the second outer pipe element (24) are connected to each other, to a “cold end” (18) in which the first inner pipe element (13) and the second inner pipe element (23, 29) are connected to each other, wherein the drive element (4, 36) is preferably arranged radially between coupling bushing (3) and coupling plug (2). [Revendication 11] Coupling (1) according to one of claims 7 to 10, wherein the first outer tube element (14) or the drive element (4, 36) is designed as a structured tube element at least in a partial section and has an outer contour in the partial section that deviates from a smooth cylindrical shape, preferably wherein the first outer tube element (14) has a number of annular bulges (15) in the partial section or wherein the first outer tube element (14) has a number of distinct local bulges in the partial section or wherein the first outer tube element (14) has a honeycomb-shaped configuration of its outer contour in the partial section. [Revendication 12] Coupling (1) according to claim 11, in which the partial section of the outer tube element (14) coincides axially with a partial section of the drive element (4, 36) in which the drive element (4, 36) is designed as a smooth tube (37), or vice versa. [Revendication 13] Coupling (1) according to one of claims 7 to 12, wherein the drive element (4, 36) has an externally accessible has a radial projection (41), preferably with a regular hexagonal shape. [Revendication 14] Coupling (1) according to claim 13, wherein the drive element (4, 36) is connected or connectable to the coupling plug (2) via the radial projection (41), preferably by means of a first clamp (5). [Revendication 15] Coupling (1) according to one of claims 7 to 14, wherein the drive element (4, 36) has an outer threaded section (42). [Revendication 16] Coupling (1) according to claim 15, wherein a screw-on part (9) is screwed or can be screwed onto the threaded section (42), in particular in the manner of a lock nut, preferably extending to the coupling bushing (3). [Revendication 17] Coupling (1) according to claim 16, wherein the drive element (4, 36) is connected or connectable to the coupling bushing (3) via the screw-on part (9), preferably by means of a second clamp (6). [Revendication 18] Coupling (1') according to one of claims 1 to 6, wherein the drive element (48) has a first annular outer connecting part (49) and a second annular inner connecting part (50) which are arranged concentrically and together form the first engagement structure and which are connected by means of a radially extending first grooved membrane disk (51), wherein preferably the first grooved membrane disk (51) is bonded to the two connecting parts (49, 50). [Revendication 19] Coupling (1') according to claim 18, wherein the coupling bushing (3) has first connection structures (52) on the second outer pipe element (24) and second connection structures (53) on the second inner pipe element (23), which together form the second engagement structure. [Revendication 20] Coupling (1') according to claim 18, wherein the first engagement structure and the second engagement structure are designed in the manner of a bayonet fitting and interact, wherein preferably, and with reference to claim 19, the first connecting structures (52) interact with the first connecting part (49) and the second connecting structures (53) interact with the second connecting part (50). [Revendication 21] Coupling (1') according to one of claims 18 to 20, wherein the coupling bushing (3) has a radially extending second grooved membrane disc (54) which connects the second outer pipe element (24) and the second inner pipe element (23) and which is arranged in a form-fitting manner to the first grooved membrane disc (51). [Revendication 22] Coupling (1') according to claim 21, wherein the second grooved diaphragm disk (54) is axially supported on the rear side. [Revendication 23] Coupling (1') according to claim 21 or 22, wherein the first grooved diaphragm disc (51) and the second grooved diaphragm disc (54) have different dimensions in the radial direction. [Revendication 24] Coupling (1') according to one of claims 18 to 23, wherein the coupling plug (2) has a radially extending third grooved membrane disc (59) which connects the first outer pipe element (14) and the first inner pipe element (13) and which is arranged in a form-fitting manner to the first grooved membrane disc (51) and the second grooved membrane disc (54). [Revendication 25] Coupling (1') according to claim 24, wherein the third grooved diaphragm disk (59) is axially supported on the rear side. [Revendication 26] Coupling (1') according to claim 24 or 25, wherein the first grooved diaphragm disc (51) and the third grooved diaphragm disc (59) have the same dimension in the radial direction.

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