EP0004492B1 - Microwave tube containing a delay line cooled by a circulating fluid - Google Patents

Microwave tube containing a delay line cooled by a circulating fluid Download PDF

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Publication number
EP0004492B1
EP0004492B1 EP79400143A EP79400143A EP0004492B1 EP 0004492 B1 EP0004492 B1 EP 0004492B1 EP 79400143 A EP79400143 A EP 79400143A EP 79400143 A EP79400143 A EP 79400143A EP 0004492 B1 EP0004492 B1 EP 0004492B1
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EP
European Patent Office
Prior art keywords
delay line
line
envelope
contact
axis
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Expired
Application number
EP79400143A
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German (de)
French (fr)
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EP0004492A3 (en
EP0004492A2 (en
Inventor
Bernard Delory
Georges Fleury
Jean-Claude Kuntzmann
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Thales SA
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Thomson CSF SA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/16—Circuit elements, having distributed capacitance and inductance, structurally associated with the tube and interacting with the discharge
    • H01J23/24—Slow-wave structures, e.g. delay systems
    • H01J23/26—Helical slow-wave structures; Adjustment therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/005—Cooling methods or arrangements

Definitions

  • the present invention relates to a microwave tube comprising a delay line cooled by fluid circulation.
  • the microwave tubes to which the invention applies such as traveling wave tubes or type 0 carcinotrons, have a delay line ensuring the interaction between an electron beam and an electromagnetic wave: in fact, the electromagnetic wave propagates on the delay line and its phase speed is made comparable to that of the electron beam which moves along the axis of the line.
  • the delay line can have various structures: helical, of the "ring and bar”, “ring and loop” type, according to English terminology ...
  • the invention is particularly applicable to cases where the focusing of the electron beam throughout the interaction space with the electromagnetic wave is carried out by a magnetic field produced by permanent magnets.
  • the invention aims to cool the delay line by fluid: it is the site of high frequency losses and, moreover, poor focusing of the electron beam can increase its heating.
  • the problem which arises is that of the arrangement of the channels where the cooling fluid circulates. This arrangement is easier when the focusing magnetic field of the electron beam is produced by an electromagnet than when it is produced by permanent, larger magnets.
  • focusing by permanent magnets has great advantages in terms of weight and consumption in particular, it is important to have the cooling channels as best as possible around a delay line focused by permanent magnets.
  • the cooling fluid circulates in channels, formed by the space between two sleeves, impervious to this fluid, having as axis the axis of the delay line.
  • the first sheath in non-magnetic material, is in contact with the face of rods which is opposite to one face of these rods in contact with the delay line, these rods, in dielectric material, being parallel to the axis of the line and regularly distributed around its perimeter.
  • the first sleeve has no contact with the delay line and seals the vacuum created in its internal volume.
  • the second sleeve contains the first with which it is in contact at different points constituting the separation between the channels in which the cooling fluid circulates.
  • the arrangement of the cooling channels according to the invention ensures cooling of the delay line more efficient than that which is achieved by the known arrangements. It allows in particular the cooling of a delay line operating in band I, for which the known arrangement which has just been mentioned is not applicable since it does not make it possible to obtain the focusing field of the beam d 'electrons.
  • the arrangement according to the invention does not cause, like the known arrangements, a significant increase in the volume of the tube.
  • FIGS. 1 a and 2 is shown, by way of example, a cross section of a microwave tube comprising a delay line cooled by circulation of fluid, of the prior art, the electron beam being focused by magnets permanent.
  • the delay line 1 which is represented has a circular section: it can be helical for example.
  • Three rods, identified by 2, made of dielectric material and good thermal conductor, such as alumina, quartz, boron nitride, glucine, are regularly distributed on the delay line. They are parallel to the axis of the line. It is known to braze these rods by one of their faces on the line in order to reduce the thermal resistance at the interface between the line and the rods.
  • FIG. 1b represents a longitudinal section of a microwave tube comprising a delay line along AA 'of FIG. 1a.
  • the focusing device by permanent magnets is adjusted on the cylindrical sheath 3. It is constituted by an alternating sequence along the axis of the line 1 of permanent magnets 4 and of polar masses 5, the faces of the same name of the magnets being opposite.
  • a collar 6 made of a material which is a good conductor of heat, copper for example, encircles the focusing device; it is crossed by channels 7 where the cooling fluid which is generally a liquid circulates.
  • this arrangement of the cooling channels does not ensure effective cooling of the delay line because the thermal resistance between the line and the channels is high: the focusing device is generally not soldered on the sheath 3 and the thermal resistance of the focusing device is important.
  • the collar 6 supporting the cooling channels 7 is adjusted on the sheath 3.
  • the collar and the channels must be made of magnetic material and good conductor of heat, copper for example.
  • the focusing device consisting of permanent magnets 4 and polar masses 5 encircles the flange 6. As has been said previously, this arrangement decreases, compared to the previous one, the thermal resistance between the line 1 and the channels 7; it therefore improves the cooling of the line, but it has the disadvantage of making it more difficult and sometimes impossible, the production of the focusing device by permanent magnets.
  • the cooling fluid of the delay line circulates in channels formed by the space between two sheaths sealed to this fluid, having for axis the axis of the line.
  • a first sheath plays the role filled in the arrangements described above by the cylindrical sheath 3: it is non-magnetic and ensures the vacuum tightness produced in its internal volume, it is in contact with the face of rods, made of dielectric material, which is opposite to one face of these rods in contact with the delay line, these rods being parallel to the axis of the line and regularly distributed around its periphery; this first sleeve has no contact with the delay line.
  • the first sheath according to the invention is distinguished from the sheaths 3 known by its section which is not necessarily circular.
  • the second sleeve contains the first with which it is in contact at different points constituting the separation between the channels in which the cooling fluid circulates.
  • the second sheath is generally a cylinder, made of non-magnetic material, on which is mounted a focusing device by permanent magnets.
  • the circular section of this second sheath allows the use of permanent magnet washers, this shape of the magnets being necessary for the proper focusing of the electron beam.
  • FIG. 3 shows, by way of example, a cross section of a microwave tube comprising a delay line, cooled by circulation of fluid according to the invention, the electron beam being focused by permanent magnets.
  • 1 be the delay line which can be helicoidal and 2 rods regularly distributed, generally three in number, made of dielectric material and good conductor of heat.
  • the rods 2 can be brazed on the line by one of their faces and brazed by their face opposite to that which is brazed on the line with the first sleeve 8.
  • the contact between the rods 2 and the line 1 on the one hand, the sleeve 8 on the other hand, can also be carried out by adjusting the sheath 8 on the rods.
  • the first sheath 8 covers the face of each rod opposite the face in contact with the line and then connects two adjacent rods in a straight line, it is therefore substantially triangular.
  • the second sleeve 9 is cylindrical and contains the first with which it is in contact at different points.
  • the first sheath 8 and the second sheath 9 are made of non-magnetic material, for example copper.
  • the technological realization of the assembly of the two sheaths represented by FIG. 3 can be as follows: two copper tubes, one circular, the other substantially triangular are brazed simultaneously with the rods 2 and the line 1.
  • the contact between the two sleeves 8 and 9 can therefore be achieved by brazing, but also by adjusting the cylindrical sheath 9 on the first sheath 8.
  • the cooling fluid circulating in the channels 10 formed by the space between the sleeves 8 and 9 can be water.
  • the first sheath 8 is made of non-magnetic material, a good thermal conductor, but not metallic, the cooling fluid must be dielectric.
  • the focusing device consisting of permanent magnets 4 and polar masses 5 is adjusted on the cylindrical sheath 9.
  • the thermal resistance between the delay line 1 and the channels 10 where the cooling fluid circulates is obviously lower with the arrangement according to the invention than with the known arrangements.
  • the brazing of the rods on the line and on the first sleeve contributes to reducing this thermal resistance.
  • the cooling of the delay line according to the invention is therefore effective.
  • the first sheath 8 does not appreciably modify the microwave characteristics of the delay line as long as the helix-mass capacity remains low. It is known that the introduction between two dielectric rods of a large helix-mass capacity modifies the microwave characteristics and in particular reduces the dispersion of the delay line. If, to widen the high frequency band, a reduction in the dispersion of the delay line is desired, the distance d between the line and the wall of the first sheath 8, in the zone where it is not in contact with an electrical rod, must be decreased. It should be noted that this reduction in the dispersion of the delay line is accompanied by a reduction in its efficiency, which is a drawback.
  • the arrangement of the cooling channels according to the invention increases only slightly (by the thickness of the first sleeve 8) the internal diameter of the focusing device shown in FIG. 1. Thus the drawbacks linked to the arrangement shown in the figure are avoided.
  • FIG. 2. The arrangement according to the invention of the cooling channels of a delay line makes it possible to reduce the space requirement of the tube required by the arrangements of known cooling channels by 30 to 40%: this reduction in volume is significant, d 'especially since these tubes are frequently airborne.
  • the cooling channels 10 are connected to circuits for supplying and discharging the cooling fluid. These connections can be made by piercing the focusing system. It is however more advantageous to place them between the flanges of the tube, next to the barrel which produces the electron beam and next to the collector which receives this beam.
  • Figure 4 is shown a longitudinal section of a variant of a microwave tube having a delay line cooled by fluid circulation according to the invention.
  • the second sleeve the role of which is to seal the cooling fluid and to ensure, when the focusing is done by permanent magnets, to the line assembly, first sleeve, cooling channels, an envelope cylindrical which supports the focusing device, is modified.
  • the second sheath shown in Figure 4 where it is generally identified by 12, has the originality of containing the polar masses 5 of the focusing device by permanent magnets.
  • the second sheath 12 is constituted by an alternating series along the axis of the delay line of cylinders made of non-magnetic material 11, for example of copper and cylinders made of magnetic material, welded end to end.
  • the cylinders made of magnetic material also carry a flange made of magnetic material in their middle and constitute the polar masses 5 of the focusing device. Washers of permanent magnets 4 are inserted between two successive flanges, the faces of the same name of the magnets being opposite.
  • the second sheath 12, like the second sheath 9, can be in contact with the first sheath 8 by brazing or simply by adjustment on the first sheath 8.
  • This variant has the advantage of reducing the internal diameter of the focusing device, therefore that of the permanent magnet washers 4: at high frequencies, bands I and J for example, we have seen that it is advantageous to reduce this as much as possible. diameter.
  • This variant also has the advantage of further contributing to the reduction in volume of the microwave tube.

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Description

La présente invention concerne un tube hyperfréquences comportant une ligne à retard refroidie par circulation de fluide.The present invention relates to a microwave tube comprising a delay line cooled by fluid circulation.

Les tubes hyperfréquences auxquels s'applique l'invention, tels que les tubes à ondes progressives ou les carcinotrons de type 0, comportent une ligne à retard assurant l'interaction entre un faisceau d'électrons et une onde électromagnétique: en effet, l'onde électromagnétique se propage sur la ligne à retard et sa vitesse de phase est rendue comparable à celle du faisceau d'électrons qui se déplace selon l'axe de la ligne.The microwave tubes to which the invention applies, such as traveling wave tubes or type 0 carcinotrons, have a delay line ensuring the interaction between an electron beam and an electromagnetic wave: in fact, the electromagnetic wave propagates on the delay line and its phase speed is made comparable to that of the electron beam which moves along the axis of the line.

La ligne à retard peut présenter diverses structures: hélicoïdale, de type "ring and bar", "ring and loop", selon la terminologie anglo- saxonne ...The delay line can have various structures: helical, of the "ring and bar", "ring and loop" type, according to English terminology ...

L'invention s'applique particulièrement aux cas où la focalisation du faisceau d'électrons tout au long de l'espace d'interaction avec l'onde électromagnétique est réalisée par un champ magnétique produit par des aimants permanents. En effet, l'invention vise à effectuer le refroidissement par fluide de la ligne à retard: celle-ci est le siège de pertes haute fréquence et de plus une mauvaise focalisation du faisceau d'électrons peut augmenter son échauffement. Le problème qui se pose est celui de la disposition des canaux où circule le fluide de refroidissement. Cette disposition est plus facile lorsque le champ magnétique de focalisation du faisceau d'électrons est produit par un électroaimant que lorsqu'il est produit par des aimants permanents, plus volumineux. Comme d'autre part, la focalisation par aimants permanents présente de grands avantages de poids et de consommation notamment, il est important de disposer au mieux les canaux de refroidissement autour d'une ligne à retard focalisée par aimants permanents.The invention is particularly applicable to cases where the focusing of the electron beam throughout the interaction space with the electromagnetic wave is carried out by a magnetic field produced by permanent magnets. In fact, the invention aims to cool the delay line by fluid: it is the site of high frequency losses and, moreover, poor focusing of the electron beam can increase its heating. The problem which arises is that of the arrangement of the channels where the cooling fluid circulates. This arrangement is easier when the focusing magnetic field of the electron beam is produced by an electromagnet than when it is produced by permanent, larger magnets. As on the other hand, focusing by permanent magnets has great advantages in terms of weight and consumption in particular, it is important to have the cooling channels as best as possible around a delay line focused by permanent magnets.

Lorsque la focalisation est réalisée par aimants permanents, il est connu de disposer les canaux de refroidissement des deux façons suivantes:

  • - les canaux de refroidissement sont montés sur une collerette encerclant le dispositif de focalisation par aimants permanents. Dans ce cas, l'efficacité du refroidissement est faible car la résistance thermique entre la ligne et les canaux de refroidissement est grande;
  • - les canaux de refroidissement sont montés, avant le dispositif de focalisation, sur une collerette en matériau amagnétique encerclant un fourreau cylindrique séparé de la ligne à retard par des baguettes en diélectrique: la résistance thermique entre la ligne et les canaux de refroidissement est donc beaucoup plus faible que dans la disposition précédente. Un autre problème se pose alors dû au dispositif de focalisation constitué d'une suite alternée, selon l'axe de la ligne, d'aimants permanents et de masses polaires, les faces de même nom des aimants étant en vis-à-vis. Dans cette disposition, le dispositif de focalisation enserre la collerette de refroidissement et son diamètre interne augmente. L'épaisseur des aimants étant maintenue constante pour des raisons de pas magnétique, l'augmentation de leur diamètre interne provoque l'accroissement du champ démagnétisant dans lequel ces aimants travaillent: dans certains cas, en particulier pour les fréquences élevées (bandes et J par exemple), le champ coercitif du matériau qui constitue les aimants peut être atteint, même si on utilise du samarium-cobalt dont le champ coercitif est élevé. La focalisation du faisceau d'électrons n'est alors plus possible.
When the focus is achieved by permanent magnets, it is known to arrange the cooling channels in the following two ways:
  • - the cooling channels are mounted on a collar encircling the focusing device by permanent magnets. In this case, the cooling efficiency is low because the thermal resistance between the line and the cooling channels is high;
  • - the cooling channels are mounted, before the focusing device, on a flange made of non-magnetic material encircling a cylindrical sheath separated from the delay line by dielectric rods: the thermal resistance between the line and the cooling channels lower than in the previous provision. Another problem then arises due to the focusing device consisting of an alternating sequence, along the axis of the line, of permanent magnets and of polar masses, the faces of the same name of the magnets being opposite. In this arrangement, the focusing device encloses the cooling collar and its internal diameter increases. The thickness of the magnets being kept constant for reasons of magnetic pitch, the increase in their internal diameter causes an increase in the demagnetizing field in which these magnets work: in certain cases, in particular for the high frequencies (bands and J by example), the coercive field of the material which constitutes the magnets can be reached, even if samarium-cobalt is used whose coercive field is high. The focusing of the electron beam is then no longer possible.

Selon l'invention, le fluide de refroidissement circule dans des canaux, constitués par l'espace compris entre deux fourreaux, étanches à ce fluide, ayant pour axe l'axe de la ligne à retard. Le premier fourreau, en matériau amagnétique, est en contact avec la face de baguettes qui est opposée à une face de ces baguettes en contact avec la ligne à retard, ces baguettes, en matériau diélectrique, étant parallèles à l'axe de la ligne et régulièrement réparties sur son pourtour. Le premier fourreau n'a aucun contact avec la ligne à retard et assure l'étanchéité au vide réalisé dans son volume intérieur. Le deuxième fourreau contient le premier avec lequel il est en contact en différents points constituant la séparation entre les canaux dans lesquels circule le fluide de refroidissement.According to the invention, the cooling fluid circulates in channels, formed by the space between two sleeves, impervious to this fluid, having as axis the axis of the delay line. The first sheath, in non-magnetic material, is in contact with the face of rods which is opposite to one face of these rods in contact with the delay line, these rods, in dielectric material, being parallel to the axis of the line and regularly distributed around its perimeter. The first sleeve has no contact with the delay line and seals the vacuum created in its internal volume. The second sleeve contains the first with which it is in contact at different points constituting the separation between the channels in which the cooling fluid circulates.

La disposition des canaux de refroidissement selon l'invention assure un refroidissement de la ligne à retard plus efficace que celui qui est réalisé par les dispositions connues. Elle permet en particulier, le refroidissement d'une ligne à retard fonctionnant en bande I, pour laquelle la disposition connue dont il vient d'être question n'est pas applicable car elle ne permet pas d'obtenir le champ de focalisation du faisceau d'électrons. La disposition selon l'invention n'entraîne pas comme les dispositions connues une augmentation importante de volume du tube.The arrangement of the cooling channels according to the invention ensures cooling of the delay line more efficient than that which is achieved by the known arrangements. It allows in particular the cooling of a delay line operating in band I, for which the known arrangement which has just been mentioned is not applicable since it does not make it possible to obtain the focusing field of the beam d 'electrons. The arrangement according to the invention does not cause, like the known arrangements, a significant increase in the volume of the tube.

D'autres objets, caractéristiques et résultats de l'invention ressortiront de la description suivante donnée à titre d'exemple non limitatif et illustrée par les figures annexées qui représentent:

  • - la figure 1 : des coupes transversale et longitudinale d'un tube hyperfréquences comportant une ligne à retard, refroidie par circulation de fluide, de l'art antérieur;
  • - la figure 2: une coupe transversale d'un tube hyperfréquences comportant une ligne à retard, refroidie par circulation de fluide, de l'art antérieur;
  • - la figure 3: une coupe transversale d'un tube hyperfréquences comportant une ligne à retard, refroidie par circulation de fluide, selon l'invention.
  • - la figure 4: une coupe longitudinale d'une variante d'un tube hyperfréquences comportant une ligne à retard, refroidie par circulation de fluide, selon l'invention.
Other objects, characteristics and results of the invention will emerge from the following description given by way of nonlimiting example and illustrated by the appended figures which represent:
  • - Figure 1: transverse and longitudinal sections of a microwave tube having a delay line, cooled by fluid circulation, of the prior art;
  • - Figure 2: a cross section of a microwave tube having a delay line, cooled by fluid circulation, of the prior art;
  • - Figure 3: a cross section of a microwave tube having a delay line, cooled by fluid circulation, according to the invention.
  • - Figure 4: a longitudinal section of a variant of a microwave tube comprising a delay line, cooled by circulation of fluid, according to the invention.

Sur les différentes figures, les mêmes repères désignent les mêmes éléments.In the different figures, the same references designate the same elements.

Sur les figures 1 a et 2 est représentée, à titre d'exemple, une coupe transversale d'un tube hyperfréquences comportant une ligne à retard refroidie par circulation de fluide, de l'art antérieur, le faisceau d'électrons étant focalisé par aimants permanents. La ligne à retard 1 qui est représentée a une section circulaire: elle peut être hélicoïdale par exemple. Trois baguettes, repérées par 2, en matériau diélectrique et bon donducteur thermique, tel que l'alumine, le quartz, le nitrure de bore, le glucine, sont régulièrement réparties sur la ligne à retard. Elles sont parallèles à l'axe de la ligne. Il est connu de braser ces baguettes par une de leurs faces sur la ligne afin de diminuer la résistance thermique à l'interface entre la ligne et les baguettes. La face de ces baguettes opposée à celle qui est brasée sur la ligne est généralement brasée à un fourreau cylindrique 3 qui est étanche, le vide étant réalisé à l'intérieur de ce fourreau, amagnétique et bon conducteur de la chaleur; ce fourreau peut être en cuivre. Lorsqu'il est métallique, ce fourreau est comme la ligne relié à la masse en continu.In FIGS. 1 a and 2 is shown, by way of example, a cross section of a microwave tube comprising a delay line cooled by circulation of fluid, of the prior art, the electron beam being focused by magnets permanent. The delay line 1 which is represented has a circular section: it can be helical for example. Three rods, identified by 2, made of dielectric material and good thermal conductor, such as alumina, quartz, boron nitride, glucine, are regularly distributed on the delay line. They are parallel to the axis of the line. It is known to braze these rods by one of their faces on the line in order to reduce the thermal resistance at the interface between the line and the rods. The face of these rods opposite to that which is brazed on the line is generally brazed to a cylindrical sheath 3 which is sealed, the vacuum being created inside this sheath, non-magnetic and good conductor of heat; this sheath can be made of copper. When it is metallic, this sheath is like the line connected to ground continuously.

La figure 1 b représente une coupe longitudinale d'un tube hyperfréquences comportant une ligne à retard suivant AA' de la figure 1a.FIG. 1b represents a longitudinal section of a microwave tube comprising a delay line along AA 'of FIG. 1a.

Sur la figure 1, le dispositif de focalisation par aimants permanents est ajusté sur le fourreau cylindrique 3. Il est constitué par une suite alternée selon l'axe de la ligne 1 d'aimants permanents 4 et de masses polaires 5, les faces de même nom des aimants étant en vis-à-vis. Une collerette 6 en matériau bon conducteur de la chaleur, du cuivre par exemple, encercle le dispositif de focalisation; elle est traversée par des canaux 7 où circule le fluide de refroidissement qui est généralement un liquide. Comme il a déjà été signalé, cette disposition des canaux de refroidissement n'assure pas un refroidissement efficace de la ligne à retard car la résistance thermique entre la ligne et les canaux est grande: le dispositif de focalisation n'est généralement pas brasé sur le fourreau 3 et la résistance thermique du dispositif de focalisation est importante.In FIG. 1, the focusing device by permanent magnets is adjusted on the cylindrical sheath 3. It is constituted by an alternating sequence along the axis of the line 1 of permanent magnets 4 and of polar masses 5, the faces of the same name of the magnets being opposite. A collar 6 made of a material which is a good conductor of heat, copper for example, encircles the focusing device; it is crossed by channels 7 where the cooling fluid which is generally a liquid circulates. As already mentioned, this arrangement of the cooling channels does not ensure effective cooling of the delay line because the thermal resistance between the line and the channels is high: the focusing device is generally not soldered on the sheath 3 and the thermal resistance of the focusing device is important.

Sur la figure 2, la collerette 6 supportant les canaux de refroidissement 7 est ajustée sur le fourreau 3. La collerette et les canaux doivent être en matériau magnétique et bon conducteur de la chaleur, du cuivre par exemple. Le dispositif de focalisation, constitué d'aimants permanents 4 et de masses polaires 5 encercle la collerette 6. Comme il a été dit précédemment, cette disposition diminue, par rapport à la précédente, la résistance thermique entre la ligne 1 et les canaux 7; elle améliore donc le refroidissement de la ligne, mais elle présente l'inconvénient de rendre plus difficile et parfois impossible, la réalisation du dispositif de focalisation par aimants permanents.In FIG. 2, the collar 6 supporting the cooling channels 7 is adjusted on the sheath 3. The collar and the channels must be made of magnetic material and good conductor of heat, copper for example. The focusing device, consisting of permanent magnets 4 and polar masses 5 encircles the flange 6. As has been said previously, this arrangement decreases, compared to the previous one, the thermal resistance between the line 1 and the channels 7; it therefore improves the cooling of the line, but it has the disadvantage of making it more difficult and sometimes impossible, the production of the focusing device by permanent magnets.

Selon l'invention, le fluide de refroidissement de la ligne à retard, circule dans des canaux constitués par l'espace compris entre deux fourreaux étanches à ce fluide, ayant pour axe l'axe de la ligne. Un premier fourreau joue le rôle rempli dans les dispositions précédemment décrites par le fourreau cylindrique 3: il est amagnétique et assure l'étanchéité au vide réalisé dans son volume intérieur, il est en contact avec la face de baguettes, en matériau diélectrique, qui est opposée à une face de ces baguettes en contact avec la ligne à retard, ces baguettes étant parallèles à l'axe de la ligne et régulièrement réparties sur son pourtour; ce premier fourreau n'a aucun contact avec la ligne à retard. Le premier fourreau selon l'invention se distingue des fourreaux 3 connus par sa section qui n'est pas obligatoirement circulaire. Le deuxième fourreau contient le premier avec lequel il est en contact en différents points constituant la séparation entre les canaux dans lesquels circule le fluide de refroidissement.According to the invention, the cooling fluid of the delay line, circulates in channels formed by the space between two sheaths sealed to this fluid, having for axis the axis of the line. A first sheath plays the role filled in the arrangements described above by the cylindrical sheath 3: it is non-magnetic and ensures the vacuum tightness produced in its internal volume, it is in contact with the face of rods, made of dielectric material, which is opposite to one face of these rods in contact with the delay line, these rods being parallel to the axis of the line and regularly distributed around its periphery; this first sleeve has no contact with the delay line. The first sheath according to the invention is distinguished from the sheaths 3 known by its section which is not necessarily circular. The second sleeve contains the first with which it is in contact at different points constituting the separation between the channels in which the cooling fluid circulates.

Le deuxième fourreau est généralement un cylindre, en matériau amagnétique, sur lequel est monté un dispositif de focalisation par aimants permanents. La section circulaire de ce deuxième fourreau permet l'utilisation de rondelles d'aimants permanents, cette forme des aimants étant nécessaire à la bonne focalisation du faisceau d'électrons.The second sheath is generally a cylinder, made of non-magnetic material, on which is mounted a focusing device by permanent magnets. The circular section of this second sheath allows the use of permanent magnet washers, this shape of the magnets being necessary for the proper focusing of the electron beam.

Sur la figure 3, est représentée, à titre d'exemple, une coupe transversale d'un tube hyperfréquences comportant une ligne à retard, refroidie par circulation de fluide selon l'invention, le faisceau d'électrons étant focalisé par aimants permanents.FIG. 3 shows, by way of example, a cross section of a microwave tube comprising a delay line, cooled by circulation of fluid according to the invention, the electron beam being focused by permanent magnets.

Soit 1, la ligne à retard qui peut être héli- coïdate et 2 des baguettes régulièrement réparties, généralement au nombre de trois, en matériau diélectrique et bon conducteur de la chaleur.Let 1 be the delay line which can be helicoidal and 2 rods regularly distributed, generally three in number, made of dielectric material and good conductor of heat.

Les baguettes 2 peuvent être brasées sur la ligne par une de leurs faces et brasées par leur face opposée à celle qui est brasée sur la ligne au premier fourreau 8. Le contact entre les baguettes 2 et la ligne 1 d'une part, le fourreau 8 d'autre part, peut être également effectué par ajustage du fourreau 8 sur les baguettes.The rods 2 can be brazed on the line by one of their faces and brazed by their face opposite to that which is brazed on the line with the first sleeve 8. The contact between the rods 2 and the line 1 on the one hand, the sleeve 8 on the other hand, can also be carried out by adjusting the sheath 8 on the rods.

Sur la figure 3, où trois baguettes diélectriques sont représentées, le premier fourreau 8 recouvre la face de chaque baguette opposée à la face en contact avec la ligne puis relie en ligne droite deux baguettes adjacentes, il est donc sensiblement triangulaire. Le deuxième fourreau 9 est cylindrique et contient le premier avec lequel il est en contact en différents points.In FIG. 3, where three dielectric rods are shown, the first sheath 8 covers the face of each rod opposite the face in contact with the line and then connects two adjacent rods in a straight line, it is therefore substantially triangular. The second sleeve 9 is cylindrical and contains the first with which it is in contact at different points.

Le premier fourreau 8 et le deuxième fourreau 9 sont en matériau amagnétique, en cuivre par exemple. La réalisation technologique de l'ensemble des deux fourreaux représentés par la figure 3 peut être la suivante: deux tubes en cuivre l'un circulaire, l'autre sensiblement triangulaire sont brasés simultanément avec les baguettes 2 et le ligne 1.The first sheath 8 and the second sheath 9 are made of non-magnetic material, for example copper. The technological realization of the assembly of the two sheaths represented by FIG. 3 can be as follows: two copper tubes, one circular, the other substantially triangular are brazed simultaneously with the rods 2 and the line 1.

Le contact entre les deux fourreaux 8 et 9 peut donc être réalisé par brasage, mais aussi par ajustage du fourreau cylindrique 9 sur le premier fourreau 8.The contact between the two sleeves 8 and 9 can therefore be achieved by brazing, but also by adjusting the cylindrical sheath 9 on the first sheath 8.

Le fluide de refroidissement circulant dans les canaux 10 constitués par l'espace compris entre les fourreaux 8 et 9 peut être de l'eau. Lorsque le premier fourreau 8 est en matériau amagnétique, bon conducteur thermique, mais non métallique, le fluide de refroidissement doit être diélectrique.The cooling fluid circulating in the channels 10 formed by the space between the sleeves 8 and 9 can be water. When the first sheath 8 is made of non-magnetic material, a good thermal conductor, but not metallic, the cooling fluid must be dielectric.

Le dispositif de focalisation constitué d'aimants permanents 4 et de masses polaires 5 est ajusté sur le fourreau cylindrique 9.The focusing device consisting of permanent magnets 4 and polar masses 5 is adjusted on the cylindrical sheath 9.

La résistance thermique entre la ligne à retard 1 et les canaux 10 où circule le fluide de refroidissement est de toute évidence plus faible avec la disposition selon l'invention qu'avec les dispositions connues. Le brasage des baguettes sur la ligne et sur le premier fourreau contribue à diminuer cette résistance thermique. Le refroidissement de la ligne à retard selon l'invention est donc efficace.The thermal resistance between the delay line 1 and the channels 10 where the cooling fluid circulates is obviously lower with the arrangement according to the invention than with the known arrangements. The brazing of the rods on the line and on the first sleeve contributes to reducing this thermal resistance. The cooling of the delay line according to the invention is therefore effective.

Le premier fourreau 8 ne modifie pas de façon sensible les caractéristiques hyperfréquences de la ligne à retard pour autant que la capacité hélice-masse reste faible. Il est connu que l'introduction entre deux baguettes diélectriques d'une capacité hélice-masse importante modifie les caractéristiques hyperfréquences et notamment diminue la dispersion de la ligne à retard. Si pour élargir la bande haute fréquence une diminution de la dispersion de la ligne à retard est souhaitée, la distance d entre la ligne et la paroi du premier fourreau 8, dans la zone où il n'est pas en contact avec une baguette électrique, doit être diminuée. Il est à noter que cette diminution de la dispersion de la ligne à retard s'accompagne de la diminution de son rendement, ce qui est un inconvénient.The first sheath 8 does not appreciably modify the microwave characteristics of the delay line as long as the helix-mass capacity remains low. It is known that the introduction between two dielectric rods of a large helix-mass capacity modifies the microwave characteristics and in particular reduces the dispersion of the delay line. If, to widen the high frequency band, a reduction in the dispersion of the delay line is desired, the distance d between the line and the wall of the first sheath 8, in the zone where it is not in contact with an electrical rod, must be decreased. It should be noted that this reduction in the dispersion of the delay line is accompanied by a reduction in its efficiency, which is a drawback.

La disposition des canaux de refroidissement selon l'invention n'augmente que légèrement (de l'épaisseur du premier fourreau 8) le diamètre interne du dispositif de focalisation représenté sur la figure 1. Ainsi sont évités les inconvénients liés à la disposition représentée sur la figure 2. La disposition selon l'invention des canaux de refroidissement d'une ligne à retard permet de réduire de 30 à 40% l'encombrement du tube demandé par les dispositions des canaux de refroidissement connus: cette réduction de volume est importante, d'autant plus que ces tubes sont fréquemment aéroportés.The arrangement of the cooling channels according to the invention increases only slightly (by the thickness of the first sleeve 8) the internal diameter of the focusing device shown in FIG. 1. Thus the drawbacks linked to the arrangement shown in the figure are avoided. FIG. 2. The arrangement according to the invention of the cooling channels of a delay line makes it possible to reduce the space requirement of the tube required by the arrangements of known cooling channels by 30 to 40%: this reduction in volume is significant, d 'especially since these tubes are frequently airborne.

Les canaux de refroidissement 10 sont reliés à des circuits d'alimentation et d'évacuation du fluide de refroidissement. Ces liaisons peuvent s'effectuer en perçant le système de focalisation. Il est cependant plus avantageux de les placer entre les flasques du tube, à côté du canon qui produit le faisceau d'électrons et à côté du collecteur qui reçoit ce faisceau.The cooling channels 10 are connected to circuits for supplying and discharging the cooling fluid. These connections can be made by piercing the focusing system. It is however more advantageous to place them between the flanges of the tube, next to the barrel which produces the electron beam and next to the collector which receives this beam.

Sur la figure 4 est représentée une coupe longitudinale d'une variante d'un tube hyperfréquences comportant un ligne à retard refroidie par circulation de fluide selon l'invention.In Figure 4 is shown a longitudinal section of a variant of a microwave tube having a delay line cooled by fluid circulation according to the invention.

Dans cette variante, le deuxième fourreau dont le rôle est d'assurer l'étanchéité au fluide de refroidissement et d'assurer, lorsque la focalisation se fait par aimants permanents, à l'ensemble ligne, premier fourreau, canaux de refroidissement, une enveloppe cylindrique qui supporte le dispositif de focalisation, est modifié. Le deuxième fourreau, représenté sur la figure 4 où il est repéré globalement par 12, présente l'originalité de contenir les masses polaires 5 du dispositif de focalisation par aimants permanents. Le deuxième fourreau 12 est constitué par une suite alternée selon l'axe de la ligne à retard de cylindres en matériau amagnétique 11, en cuivre par exemple et de cylindres en matériau magnétique, soudés bout à bout. Les cylindres en matériau magnétique portent en leur milieu une collerette en matériau magnétique également et constituent les masses polaires 5 du dispositif de focalisation. Des rondelles d'aimants permanents 4 sont insérées entre deux collerettes successives, les faces de même nom des aimants étant en vis-à-vis.In this variant, the second sleeve, the role of which is to seal the cooling fluid and to ensure, when the focusing is done by permanent magnets, to the line assembly, first sleeve, cooling channels, an envelope cylindrical which supports the focusing device, is modified. The second sheath, shown in Figure 4 where it is generally identified by 12, has the originality of containing the polar masses 5 of the focusing device by permanent magnets. The second sheath 12 is constituted by an alternating series along the axis of the delay line of cylinders made of non-magnetic material 11, for example of copper and cylinders made of magnetic material, welded end to end. The cylinders made of magnetic material also carry a flange made of magnetic material in their middle and constitute the polar masses 5 of the focusing device. Washers of permanent magnets 4 are inserted between two successive flanges, the faces of the same name of the magnets being opposite.

Le deuxième fourreau 12, comme le deuxième fourreau 9, peut être en contact avec le premier fourreau 8 par brasage ou simplement par ajustage sur le premier fourreau 8.The second sheath 12, like the second sheath 9, can be in contact with the first sheath 8 by brazing or simply by adjustment on the first sheath 8.

Cette variante présente l'avantage de diminuer le diamètre interne du dispositif de focalisation, donc celui des rondelles d'aimants permanents 4: aux fréquences élevées, bandes I et J par exemple, on a vu qu'il est intéressant de diminuer au maximum ce diamètre. Cette variante présente également l'avantage de contribuer encore à la diminution de volume du tube hyperfréquences.This variant has the advantage of reducing the internal diameter of the focusing device, therefore that of the permanent magnet washers 4: at high frequencies, bands I and J for example, we have seen that it is advantageous to reduce this as much as possible. diameter. This variant also has the advantage of further contributing to the reduction in volume of the microwave tube.

Claims (7)

1. Hyper frequency tube comprising a delay line cooled by fluid circulation and assuring interaction between an electron beam and an electromagnetic wave propagating on the line, the electron beam being focused along the axis of the line by a focusing device, characterized in that the cooling fluid circulates within channels (10) formed by the space between two envelopes which are impervious to this fluid and the axis of which is the axis of the delay line (1), the first envelope (8) of non-magnetic material being in contact with that face of rods (2) which is opposite to a face of these rods in contact with the delay line, these rods being of dielectric material and parallel to the axis of the line and regularly distributed along its periphery, the first envelope being without any contact with the delay line and assuring tightness with respect to the vacuum provided within its inner volume, the second envelope containing the first with which it is in contact at different points, forming the separation between the channels (10) in which the cooling fluid circulates.
2. Hyper frequency tube in accordance with claim 1, characterized in that the second envelope (9) is a cylinder of non-magnetic material on which a permanent magnet focusing device is mounted which is formed of an alternating series of pole masses (5) and permanent magnets (4) along the axis of the line (1), the faces of same designation of the magnets facing each other.
3. Hyper frequency tube in accordance with claim 1, characterized in that the second envelope (12) is formed by an alternating series of cylinders of non-magnetic material (11) and cylinders of magnetic material along the axis of the delay line (1) which are welded end to end, the cylinders of magnetic material bearing a sleeve of also magnetic material forming the pole masses (5) of the permanent magnet focusing device, this device further comprising permanent magnet rings (4) inserted between two successive sleeves, the faces of same designation of the magnets facing each other.
4. Hyper frequency tube in accordance with any of the preceding claims, characterized in that the contact between the rods (2) and the delay line (1) on the first hand and the first envelope. (8) on the other hand is assured by brazing.
5. Hyper frequency tube in accordance with any of the preceding claims, characterized in that the contact between the first envelope (8) and the second envelope is assured by brazing.
6. Hyper frequency tube in accordance with any of claims 1 to 5, characterized in that the connections between the channels (10) in which the cooling fluid circulates and the feeding and outlet circuits of this fluid are made through the focusing device.
7. Hyper frequency tube in accordance with any of claims 1 to 5, characterized in that the connections between the channels (10) in which the cooling fluid circulates and the feeding and outlet circuits of this fluid are made between the flanges of the tube beside the electron beam producing gun and beside the beam receiving collector.
EP79400143A 1978-03-24 1979-03-06 Microwave tube containing a delay line cooled by a circulating fluid Expired EP0004492B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7808673A FR2420842A1 (en) 1978-03-24 1978-03-24 DELAY LINE, FOR HYPERFREQUENCY TUBE, COOLED BY FLUID CIRCULATION AND HYPERFREQUENCY TUBE CONTAINING SUCH A LINE
FR7808673 1978-03-24

Publications (3)

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EP0004492A2 EP0004492A2 (en) 1979-10-03
EP0004492A3 EP0004492A3 (en) 1979-10-17
EP0004492B1 true EP0004492B1 (en) 1981-12-30

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EP79400143A Expired EP0004492B1 (en) 1978-03-24 1979-03-06 Microwave tube containing a delay line cooled by a circulating fluid

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US (1) US4243914A (en)
EP (1) EP0004492B1 (en)
DE (1) DE2961638D1 (en)
FR (1) FR2420842A1 (en)

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FR2494036A1 (en) * 1980-11-07 1982-05-14 Thomson Csf DELAY LINE FOR PROGRESSIVE WAVE TUBE, COOLED COOLING, AND PROGRESSIVE WAVE TUBE HAVING SUCH A LINE
FR2501906A1 (en) * 1981-03-16 1982-09-17 Thomson Csf Pole pieces fixing method onto exterior of TWT - uses low temp. which does not affect previous welds
DE3407206A1 (en) * 1984-02-28 1985-08-29 Siemens AG, 1000 Berlin und 8000 München WALKING PIPES AND METHOD FOR THE PRODUCTION THEREOF
DE3501971A1 (en) * 1985-01-22 1986-07-24 Spinner GmbH Elektrotechnische Fabrik, 8000 München Waveguide component
JPS62283533A (en) * 1986-05-31 1987-12-09 Nec Corp Cavity-combing type travelling-wave tube
FR2647953B1 (en) * 1989-05-30 1991-08-16 Thomson Tubes Electroniques MODEL OF CONSTRUCTION OF A PROPELLER DELAY LINE AND PROGRESSIVE WAVE TUBES USING THIS MODEL
FR2787918B1 (en) 1998-12-23 2001-03-16 Thomson Tubes Electroniques MULTIBAND PROGRESSIVE WAVE TUBE OF REDUCED LENGTH CAPABLE OF OPERATING AT HIGH POWER
CN114005720B (en) * 2021-11-09 2022-10-14 北京航空航天大学 Terahertz traveling wave tube slow wave focusing integrated structure and manufacturing method thereof

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Also Published As

Publication number Publication date
FR2420842B1 (en) 1981-05-29
FR2420842A1 (en) 1979-10-19
EP0004492A3 (en) 1979-10-17
EP0004492A2 (en) 1979-10-03
US4243914A (en) 1981-01-06
DE2961638D1 (en) 1982-02-18

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