EP1465285A1 - Coaxial line with forced cooling - Google Patents

Abstract

The coaxial cable has a tubular inner conductor (3), an outer conductor (1), insulating medium ports (5) between the inner conductor and the outer conductor and connections for passing a cooling medium through the cable. The cooling medium can be passed through the inner conductor and can be fed in and carried away via channels (5.1) formed in at least some of the insulating medium connecting ports.

Description

The invention relates to a coaxial line with a tubular Inner conductor, an outer conductor, insulating material supports between the inner conductor and the outer conductor and connections for passing a cooling medium through the Management.

Certain applications, e.g. in the field of plasma physics, require the input of RF power of more as 1MW by means of coaxial lines, the diameter of which mechanical and / or HF-technical reasons not arbitrary can be made big. Especially in continuous wave operation therefore arises on the inner conductor mainly as a result Ohmic losses and in the area of the insulation supports such a large amount of heat due to dielectric losses per time unit that forced cooling is necessary is. According to the prior art, forced cooling is used gaseous medium through the annular space between the inner conductor and passed through the outer conductor. The on this The amount of heat that can be dissipated is limited, especially since the pressure and thus the flow rate of the gaseous cooling medium for several reasons can be increased arbitrarily. For cooling superconducting Liquid helium has also been used in coaxial cables, for which, however, extensive and costly ancillary facilities are necessary.

The invention has for its object a coaxial line to create with improved cooling.

This object is achieved in that the Coolant can be passed through the inner conductor.

As a result, over the line for a given line diameter both in pulse and continuous wave mode significantly higher RF power than previously transmitted be, especially when using a liquid Cooling medium.

The cooling of the thermally much less stressed Outer conductor is not the subject of the invention. she can by means of cooling fins and cooling coils on the outer conductor or similar measures known per se.

The cooling medium is preferably in at least some of the Insulated supports designed channels can be added and removed (Claim 2).

These insulating material supports can be as through the outer conductor pipes to the outside can be formed (claim 3). Three or are usually sufficient per radial plane four insulated supports that are offset by 120 ° or 90 ° are arranged. Depending on the coolant flow required it may be sufficient to use only a part of these insulating material supports to use for the supply and discharge of the cooling medium. With a suitable design of the insulating material supports then make sure there are no additional Distortions of the RF field arise in the circumferential direction.

Alternatively, the insulating material supports can also be used as hollow disks be formed with radial channels 4), e.g. to divide the line into longitudinally dense sections.

The channels of the insulating material supports preferably open into one Chamber in an inner conductor connector at the end of the tubular inner conductor (claim 5). The inner conductor connector at the same time forms the warehouse for the respective End of the tubular inner conductor.

A preferred embodiment of the coaxial line draws is characterized in that in the tubular inner conductor tube sealed on both ends at its ends smaller diameter is arranged coaxially and that the Annulus between this tube and the tubular inner conductor communicates with the channels in the insulation supports (Claim 6). Then the cooling medium only flows through the annular gap or annulus between the tubular Inner conductor and the one enclosed and functional also at its ends on the relevant inner conductor connectors stored pipe of smaller diameter. If the ring cross-section is sufficiently dimensioned, the Cooling effect practically unchanged, while at the same time considerable lower cable weight and less effort for the auxiliary units required for coolant circulation.

Appropriately, the tube is on the end face of one Inner conductor connector trained flange closed (Claim 7).

Instead, the pipe can also have flanges on the face be closed on the respective inner conductor connector are axially and radially floating (Claim 8). Especially the play in the axial direction avoids the creation of axial constraining forces, be it as a result of manufacturing tolerances, be it because of different ones heat-dependent changes in length of the pipe and this enclosing, tubular inner conductor.

In addition, the outer circumference of the tube can counteract supporting the inner wall of the tubular inner conductor Have centering elements (claim 9). This ensures that the cross section of the annulus or annulus between the tubular inner conductor and the one enclosed by it Pipe remains constant in the circumferential direction, etc. even if the coaxial line as a whole in the longitudinal direction describes a slight curve.

The centering elements can be along a helix, i.e. be arranged helically around the tube (claim 10), uzw. also as individual, spaced apart elements.

Instead, the centering elements can be axially extending Bridges exist (claim 11). This is fluidic cheaper than the arrangement along a spiral.

In all embodiments, the centering elements can be used be in one piece with the pipe. (Claim 12). This is manufacturing technology especially advantageous if the pipe is not made of metal but plastic.

Alternatively, the tubular inner conductor in its jacket have axial channels that support the channels in the insulating material communicate (claim 13). Such one Inner conductor can be used, for example, as an extruded profile be made inexpensively from aluminum.

If the length is longer, the coaxial line consists of separate coolable from each other, electrically and mechanically connected sections (claim 14).

In this case, the tubular inner conductors are against one another bordering sections of the line are best complementary Plug connections can be connected to one another (claim 15).

Such a complementary connector can be made from a the chamber of the respective inner conductor connector final flange plate with an axially extending first ring collar exist, the second ring collar on the flange plate of the subsequent line section overlaps and itself a wreath axially extending contact springs overlapped that concentrically surrounds the second collar (claim 16). The first ring bundle forms one Plug, the second collar together with the contact spring ring the complementary coupler.

The free ends of the contact springs of the Contact spring ring in a radial plane, the opposite the end face of the second ring collar, radial plane is axially reset (claim 17). Thereby becomes when two line pieces are put together reached a pre-centering in which the first ring collar engages over the second ring collar before the end face of the first ring collar comes under the contact springs. This will prevent it from being misaligned damage to the contact springs and therefore too contact is uneven over the circumference, which are both used to create reflections and intermodulation products would lead as well to those to be transferred Overheating and currents of several 1000 amps possibly burning the contact surfaces would have.

The ring bundles bearing the contacting are expedient Flange plates with the associated inner conductor connectors screwed (claim 18). This makes it easier Retrofitting the connection points from pins to domes and vice versa. Furthermore, the contact spring ring as Single part made of the most suitable material getting produced. It will then be at its root with the Flange plate welded.

Because the tubular inner conductor is thermal despite cooling is much more heavily loaded than the outer conductor the thermal expansions that occur are taken into account. For this purpose, the insulating material supports can be in the axial direction floating through the outer conductor (claim 19).

One way to do this is for the End of the insulation support led through the outer conductor is enclosed by a guide flange in the axial Direction floating in a recess in the outer conductor held, sealed against this radially elastic and is contacted with it radially elastic (claim 20). The Radially elastic sealing can be done using O-rings and the radially elastic contact can be made by means of a helically wound and closed in a ring Contact element, a so-called worm contact, realized become.

Instead, each of the tubular insulating material supports can also be used with its inner end in the inner conductor connector and with its outer end in the Outer conductor wall mounted tiltable in an axial plane be (claim 21). The tiltable storage can be e.g. by ring beads on the relevant ends of the insulating material supports in connection with spherical counter bearings in the relevant receptacles on the inner conductor connector and on a bushing through the wall of the outer conductor realize.

Fig. 1

einen verkürzt dargestellten Leitungsabschnitt im Längsschnitt;

Fig. 2

eine teilweise im Schnitt gehaltene Stirnansicht;

Fig. 3

die zur Verbindung miteinander bestimmten Endbereiche von zwei aufeinander folgenden Leitungsabschnitten;

Fig. 4

eine Ansicht des in den Fig. 3 und 5 dargestellten Dichtungs- und Kontaktierungsrings zwischen den Verbindungsflanschen der Aussenleiter;

Fig. 5

die gleichen Endbereiche wie in Fig. 3 nach Herstellung der Verbindung;

Fig. 6

eine teilweise im Schnitt gehaltene Seitenansicht eines als 90°-Bogen ausgeführten Leitungsabschnittes;

Fig. 7

den Endbereich eines Leitungsabschnitts im Längsschnitt mit einer alternativen Ausführung der Isolierstoffstützen;

Fig. 8

die Durchführung einer Isolierstoffstütze durch den Außenleiter, überwiegend im Schnitt und in vergrößertem Maßstab als Stirnansicht;

Fig. 9

eine andere Ausführungsform der Durchführung der Isolierstoffstütze im Längsschnitt und in vergrößertem Maßstab;

Fig. 10

eine zu Fig. 9 alternative Ausführungsform;

Fig. 11

eine Stirnansicht einer anderen Ausführungsform des Innenleiterrohrs;

Fig. 12

einen Leitungsabschnitt ähnlich Fig. 1, jedoch in einer anderen Ausführungsform;

Fig. 13

einen Schnitt längs der Linie XIII-XIII in Figur 12.

In the drawing, an embodiment of a coaxial line according to the invention is shown. It shows:

Fig. 1

a shortened line section shown in longitudinal section;

Fig. 2

a partially sectioned end view;

Fig. 3

the end regions of two successive line sections intended for connection to one another;

Fig. 4

a view of the sealing and contacting ring shown in Figures 3 and 5 between the connecting flanges of the outer conductor.

Fig. 5

the same end regions as in Figure 3 after making the connection.

Fig. 6

a partially sectioned side view of a line section designed as a 90 ° bend;

Fig. 7

the end region of a line section in longitudinal section with an alternative embodiment of the insulating material supports;

Fig. 8

the implementation of an insulating material support by the outer conductor, mainly in section and on an enlarged scale as a front view;

Fig. 9

another embodiment of the implementation of the insulating support in longitudinal section and on an enlarged scale;

Fig. 10

an alternative to Fig. 9 embodiment;

Fig. 11

an end view of another embodiment of the inner conductor tube;

Fig. 12

a line section similar to Figure 1, but in another embodiment.

Fig. 13

a section along the line XIII-XIII in Figure 12.

Figure 1 shows - shortened in the longitudinal direction - a section a coolable coaxial line for the transmission of very high RF powers. The line comprises an outer conductor tube 1, equipped at both ends with connecting flanges 2 is. The diameter of the outer conductor tube 1 can are in the range of 120 mm and more. The outer conductor 1 coaxially encloses a tubular inner conductor 3 which both ends with inner conductor connectors 4 Is provided. Each of the inner conductor connectors 4 is made of a suitable dielectric via insulating material supports 5, preferably a ceramic material in which Corresponding connecting flanges 2 stored, etc. in this example with four insulated supports 5, as can be seen from FIG. 2. The insulation supports 5 are tubular and through the connecting flanges 2 sealed to the outside. Your inner Sealed ends are sealed (see Grooves for receiving O-rings) in the recesses of the inner conductor connecting pieces 4th

Chambers 6 are formed in the inner conductor connecting pieces 4, which have holes like 6.1 with channels 5.1 in the insulating material supports 5 are connected. The inner conductor connectors 4 have a first flange 4.1, overlapped by the respective end of the inner conductor tube 3 becomes. With this flange 4.1 is the one in question End of the inner conductor tube 3 preferably continuously a peripheral seam welded. Alternatively, between the circumference of the flange 4.1 and the end of the inner conductor tube 3 an O-ring can be provided (not shown).

Then there is an additional HF-technically perfect contact between the flange 4.1 and the inner conductor tube 3 necessary. Axially spaced from the first flange 4.1 the inner conductor connectors 4 have a second one Flange 4.2 of smaller diameter. This is from the respective end of a coaxially in the inner conductor tube 3 arranged pipe 7 overlapped smaller diameter. This tube 7 is not in the field-filled room and must therefore do not consist of metal. The coaxial annulus 8 between the tubular inner conductor 3 and the tube 7 communicates through holes 6.3 breakthroughs 6.2 with the Chamber 6 in the respective inner conductor connector 4, see also FIG. 2.

Via the led out connections of the insulating material supports 5 is preferred at one end of the line section liquid cooling medium, e.g. Water, fed, which then flows through the annular space 8 and over the insulating material supports 5 at the other end of the line section is subtracted. In this way, the tubular Inner conductor 3 and the inner conductor connectors 4 from cooled inside.

On their facing away from the tubular inner conductor 2 Is each chamber 6 by a flange plate 10 or 11 connected to the inner conductor connector 4 via screws 9 is connected, completed. The flange plate 10 on one (left in Fig. 1) end of the line section has an axially oriented collar 10.1 with an inner diameter d1. The flange plate 11 on the other (in Fig. 1 right) end of the line section has an annular collar 11.1 with the smaller outside diameter d2 <d1. With a flange 11.2 is connected to the flange plate 11, which coaxially surrounds the collar 11.1. The free The ends of the contact springs lie in a radial plane from the radial plane, which is the end face of the collar 11.1 contains an axial distance a is reset.

Fig. 3 illustrates that when two such line sections A and B of the collar 10.1 a plug element and the collar 11.1 together with the Contact spring ring 11.2 a coupler element for implementation the contacting connection between the tubular Inner conductors 3 of the line pieces A placed against one another and B forms. For cross-tight, contacting connection the outer conductor 1 is between the connecting flanges 2 the ring 20 shown in Fig. 4 from a feathered Sheet inserted.

In Fig. 5, the line sections A and B are together connected state shown. The outer conductor connection flanges 2 are with each other as usual via tie rods 21 screwed. Form the ring bundles 10.1 and 11.1 together the spring contact ring 11.2 a complementary Plug connection for the tubular inner conductor. In order to also in the area of these inner conductor plug connections 10.1, 11.1, 11.2 ensures adequate cooling is, these are short in the axial direction, from good thermally conductive materials and in sufficient material thickness manufactured.

Changes in direction in the course of the line are detected by means of Elbows or pipe bends realized that in principle the same structure as the straight line sections in Fig. 1 have. 6 shows a 90 ° bend. to Achieve a further degree of freedom in this If the outer conductor connection flanges 2 are additional, in known manner equipped with ball bearings 21. On the inner conductor plug connection are no further measures required because the plug part (10.1) and the coupler part (11.1, 11.2) can be rotated relative to one another as desired are.

If the field-filled space between the outer conductor and the inner conductor is to be or must be pressurized with gas, for example N ₂ , during operation of the line, longitudinally sealed connections are necessary at certain points on the line. Then, instead of the tubular insulating material supports, solid ceramic plates 57 are used, as shown in FIG. 7. These have a sufficient number of radial channels 57.1 for introducing or discharging the cooling medium. The channels 57.1 communicate on the outer circumference with an annular channel 57.2 and on the inner circumference with an annular channel 6.4 which communicates via the bores 6.3 with the chamber 6 in the inner conductor connector 4.

In operation, the inner conductor stretches despite Cooling stronger than the outer conductor. A first way this stretch, which is symbolically denoted by Δ 1 in FIG. 1 is to collect the insulation supports 5 floating through the wall of the outer conductor pass therethrough. Fig. 8 shows such a sealed and HF-tight bushing. The tubular insulation support 5 is sealed with an axial play Δ 2 an O-ring 52 received in a guide sleeve 51, the with a foot flange 53 in a recess 2.1 in the wall of the outer conductor connection flange 2 is seated. The fat of the foot flange 53 is slightly smaller than the depth of the Recess. In a groove of the foot flange 53, a so-called. Worm contact 54 recorded in the radial direction is elastic. The worm contact is in turn from one O-ring 55 enclosed. There remains a gap Δ 3. The Foot flange 53 of the guide sleeve 51 is by means of a Pressure plate 56 secured in the recess 2.1. Perpendicular to the drawing level, i.e. in the longitudinal direction of the line the recess 2.1 is elongated, so that the Insulation support 5 including the guide sleeve 51 heat-related changes in length Δ 1 of the tubular inner conductor 3 can follow relative to the outer conductor 1 and none Coercive forces occur. Leaves at the same time. this kind of Also carry out heat-related changes in length of the insulating material support 5 in the radial direction.

Another and easier way to prevent the occurrence of Coercive forces caused by changes in length due to heat To prevent the inner conductor relative to the outer conductor 9 and 10. The insulating support 5 is in the inner conductor connector 4 and in the guide sleeve 51 pivoted, either by spherical cap-shaped formation of their two ends in connection with sufficiently large recesses in the inner conductor connector 4 and in the wall of the Outer conductor connection flange 2 (Fig. 9) or, complementary for this, by forming corresponding ring beads in the recordings of the ends of the insulating support 5 on the one hand in the inner conductor connector 4 and on the other hand in the guide sleeve 51 (Fig. 10). In both cases, the Tilt the insulating sleeve around the point M by a small angle α.

In the embodiments described so far, the relatively thin, tubular inner conductor 3 through a cooling medium cooled by the smaller by means of the tube 7 Diameter created annular space 8 flows (see. Fig. 1). Alternatively, the inner conductor can be a thick-walled one Tube 30 with numerous, closely adjacent, axial Channels 31 can be executed. Fig. 11 shows the corresponding one Cross-section. In particular, made of aluminum Pipes made very easily using the extrusion process become.

FIG. 12 shows an embodiment modified from FIG. 1 shown. That of the tubular inner conductor 3 enclosed tube 7 is through at both ends Flanges 71 closed, each of which has a central one Has journal 71.1, with which he in a recess 41.1 in the inner conductor connector 41 with play in particular sits in the axial but also in the radial direction. The radial clearance is exaggerated for clarity drawn. The tube 7 is thus between the inner conductor connectors 41 floating. The space 8 between communicates the tubular inner conductor 3 and the tube 7 with the respective chamber 6 in the inner conductor connector 41 via recesses 71.2 (see FIG. 13) in the pin 71.1 and those adjoining in the radial direction Circumferential gap between the respective flange 71 and the end face of the inner conductor connecting piece facing this 41. So that the cross section of the annular space 8 remains constant over the circumference, are between the tube 7th and the tubular inner conductor 3 spacers or Centering elements 72 arranged. These can be seen in the 12 indicated way surround the tube 7 helically. Then the flow of the cooling medium in the room 8 also runs helical or helical. If this is avoided the centering elements 72 are not continuous but only arranged in the form of short sections. Instead the centering elements can also be made of axially extending ones Webs 72.1, as indicated in FIG. 13, so that the flow of the cooling medium remains axially directed.

Claims (21)

Coaxial line with a tubular inner conductor (3), an outer conductor (1), insulating material supports (5) between the inner conductor and the outer conductor and connections for passing a cooling medium through the line, characterized in that the cooling medium can be passed through the inner conductor (3). Coaxial line according to claim 1, characterized in that the cooling medium can be supplied and removed via channels (5.1) formed in at least some of the insulating material supports (5). Coaxial line according to Claim 1 or 2, characterized in that the insulating material supports are designed as tubes (5) which are led through the outer conductor (1) to the outside. Coaxial line according to Claim 1 or 2, characterized in that the insulating material supports are designed as solid disks (57) with radial channels (57.1). Coaxial line according to one of claims 1 to 4, characterized in that the channels (5.1; 57.1) of the insulating material supports (5; 57) open into a chamber (6) in an inner conductor connecting piece (4) at the end of the tubular inner conductor (3). Coaxial line according to one of claims 1 to 5, characterized in that in the tubular inner conductor (3) a tube (7) of smaller diameter which is closed at both ends is arranged coaxially and that the annular space (8) between this tube (7) and the tubular inner conductor (3) communicates with the channels (5.1; 57.1) in the insulating material supports (5; 57). Coaxial line according to one of claims 1 to 5, characterized in that the tube (7) is closed on the end face by a flange (4.2) formed on the inner conductor connecting piece (4). Coaxial line according to claim 6, characterized in that the tube (7) is closed on the end face by flanges (71) which are axially and radially floating (41.1, 71.1) mounted on the respective inner conductor connector. Coaxial line according to one of Claims 6 to 8, characterized in that the tube (7) has centering elements (72) which are supported on its outer circumference against the inner wall of the tubular inner conductor (3). Coaxial line according to one of Claims 6 to 9, characterized in that the centering elements (72) are arranged along a helix (helically) around the tube (7). Coaxial line according to one of claims 6 to 9, characterized in that the centering elements consist of axially extending webs (72.1). Coaxial line according to one of claims 6 to 11, characterized in that the centering elements are in one piece with the tube (7). Coaxial line according to one of claims 1 to 12, characterized in that the tubular inner conductor (30) has in its jacket axial channels (31) which communicate with the channels in the insulating material supports. Coaxial line according to one of claims 1 to 13, characterized in that it consists of separately coolable, electrically and mechanically interconnected sections (A, B). Coaxial line according to Claim 14, characterized in that the tubular inner conductors (3, 30) of adjoining sections (A, B) of the line can be connected to one another via complementary plug connections. Coaxial line according to Claim 15, characterized in that the complementary plug connection consists of a flange plate (10) which closes off the chamber (6) of the inner conductor connecting piece (4) and has an axially extending first annular collar (10.1) which connects a second annular collar (11.1) to the The flange plate (11) of the adjoining line section overlaps and is in turn contacted by a ring (11.2) which axially extends contact springs, which concentrically surrounds the second collar (11.1). Coaxial line according to claim 16, characterized in that the free ends of the contact springs of the contact spring ring (11.2) lie in a radial plane which is axially set back from the radial plane containing the end face of the second ring collar (11.1). Coaxial line according to claim 17, characterized in that the flange plates (10, 11) are screwed to the inner conductor connecting piece (4). Coaxial line according to one of claims 1 to 18, characterized in that the insulating material supports (5) are guided in a floating manner in the axial direction through the outer conductor (1). Coaxial line according to one of Claims 1 to 19, characterized in that the end of each insulating material support (5) which is passed through the outer conductor (1) is enclosed by a guide flange (51) which, in the axial direction, is held in a recess in the outer conductor, in relation to the latter radially elastic sealed and contacted with it radially elastic. Coaxial line according to one of claims 1 to 20, characterized in that each of the tubular insulating material supports (5) with its inner end in the inner conductor connecting piece (4) and with its outer end in the outer conductor wall (1) is tiltably mounted in an axial plane.

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