Coaxial cable

Abstract

The present invention relates to a coaxial cable for mechanical attachment to and signal coupling of a measuring head to a process engineering plant, wherein the coaxial cable has an inner conductor and an outer conductor surrounding the inner conductor, wherein the outer conductor runs coaxially to the inner conductor on the inside, while the outer conductor, in order to reduce thermal conductivity in the longitudinal direction, has at least one recess on the outside reducing the cross-sectional area of ​​the outer conductor, which is covered by a stabilizer, and an arrangement thereof.

Description

[0001] The present invention relates to a coaxial cable for mechanical attachment to a process engineering plant, in particular for high temperature applications, and signal coupling of a measuring head to this plant, as well as an arrangement thereof.

[0002] Coaxial cables are suitable for transmitting high-frequency signals and have an inner conductor and an outer conductor surrounding the inner conductor, the outer conductor being coaxial with the inner conductor. The inner conductor, also called the core or signal conductor, typically carries the signal, while the outer conductor carries return currents. Coaxial cables according to the present invention have, in particular, a characteristic impedance of more than 10 ohms and / or less than 300 ohms, typically more than 40 ohms and / or less than 80 ohms.

[0003] The inner conductor and the outer conductor are insulated from each other by a dielectric material placed between them. The inner conductor and the outer conductor preferably have a distance between them that is at least substantially constant. In other words, the inner conductor and the outer conductor have interfaces facing each other that are concentric in cross-section. The dielectric material is preferably arranged in a ring-shaped cross-section between the inner conductor and the outer conductor.

[0004] The coaxial cable of this type is, in particular, an extension, especially a high-temperature extension, i.e., an extension piece, used to transmit a preferably high-frequency signal between the process equipment and the measuring head. The coaxial cable makes it possible to increase the distance between the equipment and the measuring head and / or to improve thermal decoupling between the equipment and the measuring head. The coaxial cable is preferably dimensionally stable to allow the measuring head to be attached to the equipment and preferably to be supported in a cantilevered position.

[0005] Increasing the thermal resistance in the longitudinal direction and the associated thermal decoupling is particularly useful or even necessary when using measuring heads on process engineering plants for high-temperature applications, in order to enable the operation of measuring heads without unacceptably high thermal stress.

[0006] In general, high-temperature applications within the meaning of the present invention are particularly those applications in which a system housing (cover, pipe, tank, etc.) to which the measuring head is or is to be attached with or without an extension exceeds 80 °C, 120 °C, or 150 °C during operation of the system. Examples of high-temperature applications include combustion processes, steam-based processes, processes in (bio)reactors, processes in distillation columns, and the like.

[0007] Common coaxial cables of this type typically need to be quite long to achieve sufficient thermal decoupling and cooling. While designs with integrated cooling fins in the outer conductor may allow for somewhat shorter lengths, this comes at the expense of bending stiffness. This lowers the mechanical resonant frequency of the coaxial cable and sensor system, potentially leading to vibration and damage to the sensor.

[0008] An objective technical object of the present invention is therefore to provide a coaxial cable for mechanical attachment to a process plant and signal coupling of a measuring head to the process plant and an arrangement thereof, which can be implemented in a shorter or more compact form while avoiding impairments to reliability.

[0009] This problem is solved by a coaxial cable according to claim 1 or an arrangement according to claim 10. Advantageous embodiments are the subject of the dependent claims.

[0010] A first aspect of the present invention relates to a generic coaxial cable for the mechanical fastening and signal coupling of a measuring head to a process engineering plant, comprising an inner conductor and an outer conductor surrounding the inner conductor, which runs coaxially to the inner conductor on the inside.

[0011] As proposed, the outer conductor has at least one recess on its outer side to reduce thermal conductivity in the longitudinal direction, which reduces the cross-sectional area of ​​the outer conductor and is covered, preferably bridged, by a stabilizer.

[0012] It has been surprisingly shown that the thermal resistance in the longitudinal direction can be increased by the recess without significant loss of stability when combined with the proposed stabilizer. The recess reduces the thermal conductivity in the longitudinal direction (signal flow direction or longitudinal extent of the inner conductor). Specifically, the outer conductor has a region with a reduced outer diameter, which forms the recess.

[0013] The stabilizer covers or bridges the recess and thereby preferably completely, at least partially, or predominantly compensates for a reduction in the stability, in particular the bending stiffness, of the coaxial cable that would otherwise occur due to the expansion or reduction of the outer conductor's wall thickness. Surprisingly, it has been shown that, with sufficient or even essentially unchanged stability, the thermal resistance in the longitudinal direction can be significantly reduced by the proposed design.

[0014] Consequently, the coaxial cable can be made shorter and more compact without excessively stressing the measuring head. The electrical properties are not altered by the recess and the stabilizer, as the signal-conducting areas, such as the inner conductor and the inner surface of the outer conductor facing the inner conductor, remain coaxial.

[0015] Another aspect of the present invention, which can also be implemented independently, relates to an arrangement comprising a proposed coaxial cable, a measuring head, and preferably a process engineering system for high-temperature applications. The coaxial cable has a measuring head connection mechanically and electrically connected to the measuring head and a system connection that is mechanically and electrically connected or connectable to the system. The arrangement can include an antenna, a coupler, a sensor, a sensor front end, and / or a measuring probe, which is / are connected to the system connection for signal transmission, such that signals representing a process variable can be transmitted via the coaxial cable.

[0016] The setup could, for example, include a level, limit level, and / or pressure measuring device. However, the coaxial cable can also be used with other measuring heads. Therefore, the coaxial cable can also be used for other, preferably process-related, monitoring applications.

[0017] The measuring head is preferably rigidly connected to the system via the coaxial cable, or can be connected in this way. This allows it to be held on the system without requiring an additional holding device.

[0018] The measuring head can form a guided radar system by connecting it via the coaxial cable. For example, this can create a level measurement system that can also be used for measuring hot substances such as liquids.

[0019] A coaxial cable according to the present invention is preferably a passive device for transmitting high-frequency signals, in particular radar signals. The coaxial cable preferably has end-end connections for the measuring head and for the system and connects these via the inner conductor for signal transmission, or is designed to do so. In addition, the connections preferably also form a mechanical connection to the measuring head and to the system, so that the measuring head can be attached to the system via the dimensionally stable coaxial cable.

[0020] The coaxial cable is preferably designed to transmit a signal from the system or from a coupler connected to the coaxial cable on the system side, an antenna connected to the coaxial cable on the system side, a sensor or front end of the sensor connected to the coaxial cable on the system side, or a measuring probe connected to the coaxial cable on the system side to the measuring head and / or vice versa.

[0021] The coaxial cable's system connection can therefore be connected or connectable to an antenna or other interface for coupling (radar) signals into an interior space of the system and / or coupling (radar reflection) signals from the interior space of the system into the coaxial cable. Alternatively or additionally, a sensor or sensor front end is connected or connectable to the system connection, whereby the sensor or front end detects or receives a process variable and couples a corresponding signal into the coaxial cable. The connection for the measuring head can be connected or connectable to an input and / or output of the measuring head's electronics.

[0022] A measuring head according to the present invention is preferably a metrological electronics unit for determining a process parameter of the system or comprises such electronics. The measuring head is preferably configured to transmit signals to and / or receive signals from the coaxial cable.

[0023] Preferably, the measuring head is an electronic device for determining a fill level, for which purpose the measuring head transmits and / or receives (radar) signals via the coaxial cable. In one example, the measuring head includes a radar transceiver for generating, receiving, and / or processing radar signals generated and / or reflected within the system. A combination of measuring head and coaxial cable can form a guided radar system or part thereof.

[0024] The measuring head can be connected to a coupler or antenna via the coaxial cable. The coupler or antenna can be designed and / or positioned within the interior of the system for transmitting and receiving (radar) signals.

[0025] Further aspects and advantages of the present invention will become apparent from the claims and the following description of a preferred embodiment with reference to the drawing. It shows: Fig. 1. a longitudinal section of a proposed coaxial cable; Fig. 2 a cross-section of the proposed coaxial cable according to section line II-II from Fig. 1; Fig. 3 a cross-section of the proposed coaxial cable according to section line III-III from Fig. 1; and Fig. 4 a perspective explosion of the proposed coaxial cable.

[0026] The figures use the same reference symbols for identical or similar parts, whereby the same or similar properties can be achieved even without repeated description.

[0027] Fig. Figure 1 shows a longitudinal section of a proposed coaxial cable 1. This cable is dimensionally stable, so that it is suitable or is used to attach a measuring head 2 to a process engineering system 3 and / or to hold it in a self-supporting manner.

[0028] The coaxial cable 1 has an inner conductor 4 and an outer conductor 5.

[0029] In this case, a (cylindrical-shaped) inner surface or inside surface 6 of the outer conductor 5 and the inner conductor 4 or a (cylindrical-shaped) outer surface of the inner conductor 4 run coaxially.

[0030] The surfaces of the outer conductor 5 and the inner conductor 4 facing each other form concentric circles in cross-section.

[0031] The outer conductor 5 is preferably formed from a single piece of solid material, in particular from stainless steel or another metal.

[0032] The inner conductor 4 can also be formed from a single piece of solid material, in particular from stainless steel or another metal. Alternatively, the inner conductor 4 can also be or comprise an electrically conductive, preferably metallic, rope or wire rope.

[0033] Furthermore, in the illustrated example, the outer conductor 5 and the inner conductor 4 are made of the same material, in particular stainless steel. However, they can also be made of different conductive materials, preferably metals.

[0034] Fig. Figure 2 shows a cross-section of the coaxial cable 1 according to section line II-II. Fig. 1 and Fig. Figure 3 shows a cross-section of the coaxial cable 1 according to section line III-III. Fig. 1.

[0035] To reduce thermal conductivity in the longitudinal direction 7, the outer conductor 5 is proposed to have at least one recess 10 on its outer side, reducing the cross-sectional area 9 of the outer conductor 5, which is covered by a stabilizer 11. The recess 10 is realized in particular by reducing the outer diameter of the outer conductor 5.

[0036] The stabilizer 11 is preferably formed from a single piece of solid material, in particular stainless steel, or another metal. Furthermore, in the illustrated example, the outer conductor 5 and the stabilizer 11 are formed from the same material, in particular stainless steel. However, they can also be formed from different materials, preferably metals.

[0037] The reduction of the cross-sectional area 9 of the outer conductor 5 achieved by the recess 10 has proven advantageous for the reduction of the thermal conductivity, surprisingly so despite the stabilizer 11 covering or bridging the recess 10, which contributes to heat conduction.

[0038] The stabilizer 11 compensates for or reduces a reduction in the bending stiffness of the coaxial cable 1, which would otherwise result from the reduced cross-sectional area 9 in the area of ​​the recess 10.

[0039] Surprisingly, the combination of the recess 10 and the stabilizer 11 exhibits a significantly lower thermal conductivity in the longitudinal direction 7 (in the direction of the signal or the longitudinal extent of the inner conductor 4) than a coaxial cable 1 without recess 10 and stabilizer 11, while maintaining similar stability (flexural stiffness) of the coaxial cable 1.

[0040] The recess 10 is preferably formed by an outer, at least substantially completely circumferential annular groove. The recess 10 is preferably uninterrupted.

[0041] The depth 12 of the recess 10 preferably corresponds to the distance or clear width between the outside of the outer conductor 5 and the stabilizer 11 (the inside of the stabilizer 11).

[0042] The depth 12 is preferably at least substantially constant across the recess 10. However, the conditions preferred according to the proposal also apply alternatively or additionally to a maximum, average, or minimum depth 12.

[0043] The recess 10 is preferably at least substantially hollow cylindrical. It can be embedded in the outer conductor 5 and / or between the outer conductor 5 and the stabilizer 11 and / or define a space.

[0044] The recess 10 preferably extends in longitudinal direction 7 over a length that is greater than an outer diameter 21 of the outer conductor 5 in the area of ​​the recess 10.

[0045] The stabilizer 11 has an inner diameter that corresponds to the outer diameter of the outer conductor 5 outside the recess 10. The depth 12 can therefore also be understood, independently of the stabilizer 11, as the difference between the diameters of the outer conductor 5 outside the recess 10 and within the recess 10.

[0046] In the area of ​​the recess 10, the outer conductor 5 preferably has a cross-sectional area 9 and / or wall thickness 14 that is reduced by at least 50% compared to the outer conductor 5 in the areas of the holding sections 15, 16.

[0047] A longitudinal extent 13 of the recess 10 preferably exceeds the depth 12.

[0048] The recess 10 preferably extends over more than 10%, in particular more than 20% or 30%, in the illustrative example more than 50% of the longitudinal extent of the outer conductor 5.

[0049] In the recess 10, the clear width between an outer circumferential surface (outer side 8) of the outer conductor 5 and the stabilizer 11 is preferably larger than a wall thickness 14 of the outer conductor 5 in this area.

[0050] The outer conductor 5 preferably has retaining sections 15, 16 adjacent to the recess 10, which are mechanically coupled to each other by the stabilizer 11. The stabilizer 11 is preferably firmly connected to the outer conductor 5 in the retaining sections 15, 16. The stabilizer 11 is particularly preferably welded to the retaining sections 15, 16, but can also be glued, screwed, or otherwise fastened.

[0051] A preferred option is a connection between the stabilizer 11 and the outer conductor 5 that is not displaceable in the longitudinal direction relative to the holding sections 15, 16. This allows the holding sections 15, 16 to support each other when bending moments occur, thus enabling a high bending stiffness of the coaxial cable 1.

[0052] It has surprisingly been shown that the external stabilizer 11 requires a smaller wall thickness 18 and a smaller cross-sectional area 19 for sufficient stability and bending stiffness than the cross-sectional area of ​​the recess 10. Thus, the recess 10 and the stabilizer 11 result in a reduced overall cross-sectional area compared to the outer conductor 5 without the recess 10 and without the stabilizer 11. This leads to the advantageously higher thermal resistance.

[0053] The sum of the wall thicknesses 14, 18 and / or the cross-sectional areas 9, 19 of the outer conductor 5 and the stabilizer 11 in the region of the recess 10 is preferably less than the wall thickness 17 and / or cross-sectional area 20 of the outer conductor 5 at the retaining sections 15, 16. In other words, the wall thickness 17 of the outer conductor 5 at the retaining sections 15, 16 is preferably greater than the sum of the wall thickness 14 of the outer conductor 5 and the wall thickness 18 of the stabilizer 11 in the region of the recess 10. The same preferably applies to the cross-sectional areas. Thus, the cross-sectional area 20 of the outer conductor 5 at the retaining sections 15, 16 is preferably greater than the sum of the cross-sectional area 9 of the outer conductor 5 and the cross-sectional area 19 of the stabilizer 11 in the region of the recess 10.

[0054] The stabilizer 11 is preferably formed by a sleeve (pipe section) covering the recess 10 and / or is at least substantially hollow cylindrical. The stabilizer 11 preferably has a longitudinal extent that exceeds the longitudinal extent 13 of the recess 10. The stabilizer 11 preferably has an inner diameter that allows the stabilizer 11 to be slid over the outer conductor 5 until it covers the recess 10. The stabilizer 11 can form a sleeve for the recess 10.

[0055] The diameters 22 of the outer conductor 5 in the area of ​​the holding sections 15, 16 preferably correspond to the inner diameter or corresponding inner diameters of the stabilizer 11.

[0056] The stabilizer 11 can have recesses, in particular openings 23. These can establish a continuous connection between the environment and a space formed by the recess 10 or between the recess 10 and the stabilizer 11. This can reduce the thermal conductivity of the stabilizer 11 in the longitudinal direction. Alternatively or additionally, cooling can be implemented. In this case, a coolant, in particular air, another gas, or a cooling liquid, can be passed through the recess 10.

[0057] Alternatively or additionally, the space formed between the recess 10 and the stabilizer 11 can be completely or partially filled with a thermal insulator. For example, the space can be filled with foam. The space can also be evacuated or filled with a gas that has a lower thermal conductivity than air (as in a thermos flask or insulated windows).

[0058] At one end of the coaxial cable 1, a dead space 24 between the inner conductor 4 and the outer conductor 5, or between the inner conductor 5 and a fastening element 31 extending the outer conductor 5, is closed, preferably with fused glass, or with another type of closure 25. This closure 25 preferably forms a sealing plane against an interior space of the system 3. The closure 25 acts as a dielectric, i.e., it is insulating, and is arranged between the inner conductor 4 and the outer conductor 5. The closure 25 preferably forms a fused glass bond between the inner conductor 4 and the outer conductor 5, or between the fastening element 31 and the outer conductor 5.

[0059] A dielectric 26, separated from the closure 25, is preferably arranged between the inner conductor 4 and the outer conductor 5. The dielectric 26 preferably has a dielectric constant that corresponds at least substantially to the dielectric constant of the closure 25, and in particular deviates from it by less than 20%. This prevents signal interference and reflections.

[0060] The dielectric 26 can be made of a ceramic or glass. In the illustrated example, it is made of glass-ceramic.

[0061] The dielectric 26 preferably fills the dead space 24 between the outer conductor 5 and the inner conductor 4 at least substantially completely. It has been shown that this prevents the accumulation of condensation.

[0062] In the illustrated example, the dielectric 26 is two-part or multi-part, but it can also be implemented as a single piece. In the illustrated example, the dielectric 26 is tubular. This allows it to center the inner conductor 4 and ensure a constant distance between the inner conductor 4 and the outer conductor 5.

[0063] The coaxial cable 1 preferably has a clamping device 27 that clamps the dielectric 26 in the direction of the closure 25. This ensures a secure fit even with different coefficients of thermal expansion of the components (inner conductor 4, outer conductor 5, dielectric 26).

[0064] The clamping device 27 preferably has a similar dielectric constant to the dielectric 26. In particular, the clamping device 27 is a compressed elastomer or another compressible, flexible and / or elastic material, for example silicone, especially as a molded part or foam cutout, which is compressed against the dielectric 26. The clamping device 27 is preferably tubular, especially like the dielectric 26, but may have a tapered tube wall towards one end, especially towards the dielectric 26.

[0065] The clamping device 27 can be pressed against the dielectric 26 by a closure 28.

[0066] In the exemplary embodiment, the inner conductor 4 is composed of two or more segments. These segments are preferably connected to each other in a centered position by means of plug connectors. However, it is also possible, in principle, to form the inner conductor 4 from only one or from more than two segments.

[0067] The coaxial cable 1 preferably has two end connections 29, 30. The connections 29, 30 can be implemented as a plug and / or a socket. Furthermore, the connections are preferably designed for the mechanical fastening of the coaxial cable 1. The connections 29, 30 are preferably located at opposite ends or end faces of the coaxial cable 1.

[0068] In the illustrated example, the coaxial cable 1 has a measuring head connection 29 for attaching and electrically connecting the measuring head 2 to the coaxial cable 1 or via the coaxial cable 1 to the system A and a system connection 30 for the mechanical and electronic connection of the coaxial cable 1 to the system 3.

[0069] The coaxial cable 1 can have a fastening device 31 at the system connection 30 for attaching the coaxial cable 1 to the system A. In particular, this is a screw fastening device, but it can also be implemented differently. The fastening device 31 can be held on the outer conductor 5, in particular by screwing it on or forming it integrally with it. The fastening device 31 can be a union nut or have one. The system connection 30 can be attached directly to the system A with the fastening device 31 or via a flange (not shown). The flange can be attached to the fastening device 31, for example by screwing it on, welding it on, or, more generally, preferably by positive locking, force locking, and / or a material locking connection.

[0070] As in Fig.As indicated in Figure 1, a coupler 32 arranged on or in the system A can be connected to the coaxial cable 1. The coupler 32 can be an antenna or other coupling structure for coupling the signal, which is or can be carried via the coaxial cable 1, into an interior space of the system A or into a measuring probe or the like.

[0071] The coaxial cable 1 can be electronically connected to an electronics 33 of the measuring head 2 at the measuring head connection 29 and / or mechanically connected to a housing 34 of the measuring head 2.

[0072] To manufacture the coaxial cable 1, the recess 10 is preferably machined into a blank (thick-walled round tube or round rod), thereby creating the outer conductor 5. For this purpose, the blank can be turned from stainless steel or another metal.

[0073] The stabilizer 11 is then slid over the outer conductor 5, screwed and / or pressed until it covers the recess and overlaps laterally. In the overlap area, which corresponds to the retaining sections 15, 16 adjacent to the recess 10, the stabilizer 11 is then connected to the outer conductor 5. For this purpose, the stabilizer 11 can preferably be welded to the retaining sections 15, 16 all the way around. Adjacent to one of the retaining sections 15, 16, in the illustrated example on a side facing away from the recess 10 and / or facing the system side, the outer conductor 5 can have a stop for defining a position of the stabilizer 11.

[0074] In the illustrated example, the fastening element 31 is attached to the system side of the coaxial conductor 1 and extends the outer conductor 10. The fastening element 31 preferably has a cylindrical opening into which the inner conductor 4 is inserted centrally or concentrically and sealed by the closure 25. Specifically, the inner conductor 4 is arranged and / or sealed coaxially with the inner surface of the fastening element 31, which is at least substantially cylindrical and / or preferably also at least substantially cylindrical, and aligned with the inner circumferential surface of the outer conductor 5. The fastening element 31 thus preferably extends the dead space 24 of the outer conductor 5.

[0075] The inner conductor 4 is preferably guided through the fastening element 31 and / or sealed within the fastening element 31 by means of the closure 25. Because the fastening element 31 is sealed with the closure 25, it closes off the outer conductor 5. The closure 25 is preferably realized by a glass fusion bond. For this purpose, glass can be melted in a continuous furnace. However, other methods are also possible.

[0076] The preferably tubular dielectric 26 is inserted between the inner conductor 4 and the outer conductor 5. If the dielectric 26 is multi-part, as in the illustrated example, the parts can be inserted sequentially into the dead space 24 surrounding the outer conductor 5. In the illustrated example, the inner conductor 4 is multi-part, so that one or more parts of the inner conductor 4 can be inserted into its interior (dead space 24) after the dielectric 26 has been positioned. If the inner conductor 4 is a single piece, the dielectric 26 can also be inserted between the inner conductor 4 and the outer conductor 5.

[0077] Finally, the clamping device 27 is inserted into the dead space 24, or space between the inner conductor 4 and the outer conductor 5, on the side of the inner conductor 4 facing away from the closure 25, so that the clamping device 27 clamps the dielectric 26 against the closure 25. For this purpose, the clamping device 27 can be compressed by the closure 28. In the illustrated example, the closure 28 is a sleeve with an opening for the inner conductor 4. The closure 28 can have an external thread with which it is fastened to the outer conductor 5. However, it can also be glued, pressed in, or otherwise fastened.

[0078] Different aspects of the present invention can be implemented independently and combined with one another, resulting in synergistic effects, although this is not explicitly explained for each individual combination. Reference symbol list: 1 coaxial cable 2 measuring heads 3 Process engineering plant 4 inner conductors 5 external conductors 6 Inside (outer conductor) 7 Longitudinal direction 8 Outside External conductor 9 Cross-sectional area of ​​the outer conductor in the area of ​​the recess 10. Recess of the outer conductor 11 Stabilizer 12 Depth of recess (clear width outer conductor - stabilizer) 13 Longitudinal extent of the recess 14 Wall thickness of the outer conductor in the area of ​​the recess 15 Holding section measuring head side 16 Stop section Plant side 17 Wall thickness of the outer conductor in the holding section 18 Wall thickness of the stabilizer 19 Cross-sectional area of ​​the stabilizer 20 Cross-sectional area of ​​the outer conductor in the area of ​​the holding sections 21 Outer diameter of the outer conductor in the area of ​​the recess 22 Outer diameter of the outer conductor in the area of ​​the holding sections 23 Stabilizer Breakthrough 24 dead space 25 Closure 26 Dielectric 27 clamping devices 28 Closure 29 Measuring head connection 30 plant connection 31 Fasteners 32 couplers 33 Electronics 34 Housing of the measuring head A Arrangement

Claims

Coaxial cable (1) for mechanical attachment to and signal coupling of a measuring head (2) with a process engineering plant (3), wherein the coaxial cable (1) has an inner conductor (4) and an outer conductor (5) surrounding the inner conductor (4), wherein the outer conductor (5) runs coaxially to the inner conductor (4) on the inside, while the outer conductor (5) has at least one recess (10) on the outside reducing a thermal conductivity in the longitudinal direction, which is covered by a stabilizer (11). Coaxial cable according to claim 1, characterized in that the recess (10) in the outer conductor (5) is formed by an outer, at least substantially completely circumferential annular groove. Coaxial cable according to claim 1 or 2, characterized in that a longitudinal extent (13) of the recess (10) exceeds a depth (12) of the recess (10) and / or a wall thickness (14) of the outer conductor (5) in the area of ​​the recess (10). Coaxial cable according to one of the preceding claims, characterized in that the outer conductor (5) has retaining sections (15, 16) adjacent to the recess (10) which are mechanically coupled to each other by the stabilizer (11). Coaxial cable according to claim 4, characterized in that the sum of the wall thicknesses (14, 18) and / or the cross-sectional areas (9, 19) of the outer conductor (5) and the stabilizer (11) in the area of ​​the recess (10) is less than the wall thickness (17) and / or cross-sectional area (20) of the outer conductor (5) at the retaining sections (15, 16). Coaxial cable according to one of the preceding claims, characterized in that the stabilizer (11) is formed by a sleeve covering the recess (10), is a pipe section and / or is at least substantially hollow cylindrical. Coaxial cable according to one of the preceding claims, characterized in that the stabilizer (11) has one or more recesses, in particular openings (23), to reduce the thermal conductivity of the stabilizer (11) in the longitudinal direction. Coaxial cable according to one of the preceding claims, characterized in that at one end of the coaxial cable (1) a dead space between the inner conductor (4) and the outer conductor (5) is closed with a closure (25), in particular glass, preferably fused in. Coaxial cable according to claim 8, characterized in that a dielectric (26) separate from the closure (25) is arranged between the inner conductor (4) and the outer conductor (5), preferably wherein the dielectric (26) has a dielectric constant which differs from the dielectric constant of the closure (25) by less than 20%, and / or wherein the coaxial cable (1) has a tensioning means (27) which tensions the dielectric (26) in the direction of the closure (25). Arrangement comprising a coaxial cable (1) according to one of the preceding claims, a measuring head (2) and a process engineering system (3) for high-temperature applications, wherein the coaxial cable (1) has a measuring head connection (29) mechanically and electrically connected to the measuring head (2) and a system connection (30) mechanically and electrically connected or connectable to the system (3), preferably wherein the measuring head (2) can be freely attached to the system (3) and forms a signal connection between the measuring head (2) and the system (3) and / or wherein a guided radar system is formed.

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