EP0010461B1 - Bei hoher Temperatur funktionsfähiges antimikrophonisches Koaxialkabel - Google Patents

Bei hoher Temperatur funktionsfähiges antimikrophonisches Koaxialkabel Download PDF

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Publication number
EP0010461B1
EP0010461B1 EP19790400610 EP79400610A EP0010461B1 EP 0010461 B1 EP0010461 B1 EP 0010461B1 EP 19790400610 EP19790400610 EP 19790400610 EP 79400610 A EP79400610 A EP 79400610A EP 0010461 B1 EP0010461 B1 EP 0010461B1
Authority
EP
European Patent Office
Prior art keywords
core
beads
coaxial cable
metallic
cable according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19790400610
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English (en)
French (fr)
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EP0010461A1 (de
Inventor
Georges Melet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
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Publication date
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Publication of EP0010461A1 publication Critical patent/EP0010461A1/de
Application granted granted Critical
Publication of EP0010461B1 publication Critical patent/EP0010461B1/de
Expired legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B11/00—Communication cables or conductors
    • H01B11/18—Coaxial cables; Analogous cables having more than one inner conductor within a common outer conductor
    • H01B11/1834—Construction of the insulation between the conductors
    • H01B11/1856—Discontinuous insulation

Definitions

  • the invention relates generally to coaxial cables which are used in electronics techniques for transmitting electrical signals of very low intensity and applies more particularly to those of these cables which operate in medium hostile and high temperature.
  • Such a coaxial cable known per se is shown in FIG. 1 and consists of two electrodes, namely a central core 1 and an outer braid 3 separated by a dielectric medium 2 surrounding the central core.
  • the central core 1 is generally made of sometimes tinned red copper
  • the dielectric 2 is made of a material with high resistivity such as Teflon
  • the external conductive braid 3 is generally made of sometimes silvery red copper.
  • This antimicrophonic protection in itself known, however, has the disadvantage that it does not overcome the electric charges induced by the friction phenomena developing between the core 1 and the dielectric 2; on the other hand, when it comes to making a coaxial cable operating in a hostile environment having vibrations and in particular at a high temperature of the order of several hundred degrees Celsius as is the case for the transmission of measurements coming from a nuclear reactor core, it is then impossible to use such an intermediate plastic envelope and the problem of microphonic protection of the cable is then completely called into question.
  • the coaxial cables undergo a transformation essentially concerning their dielectric, which then consists of a number of high density ceramic beads, generally in pure alumina, strung on the core of the cable and covered by an outer stainless steel braid.
  • Fig. 1 shows such a coaxial cable for high temperature of a type known per se.
  • a coaxial cable comprising a central core 1 of stainless steel or copper covered with stainless steel on which beads 2, made of pure alumina, constituting the dielectric are strung.
  • the pearls 2 preferably have the shape of a portion of a cylinder limited by respectively convex and concave end surfaces so as to be able to fit perfectly into each other.
  • the second electrode of this cable consists of an outer braid 3, also made of stainless steel and which may comprise several layers.
  • the present invention specifically relates to an antimicrophonic coaxial cable which can operate in a hostile environment and in particular at high temperature, without having the drawbacks of the prior art.
  • the coaxial cable also includes a certain number of metallic intermediate pieces threaded on the core and placed between each of the consecutive beads, which gives it a certain complementary flexibility.
  • the metallic coating of the friction surfaces can be produced in two different ways.
  • the metallic coating of said surfaces is produced by means of a deposit made on the parts of the surface thereof which are in contact with the core, the braid and / or the intermediate pieces, said deposit possibly being constituted for example by an alloy of molybdenum and manganese obtained from a pulverulent solution in an appropriate solvent which is left to dry and which is fixed by a treatment at a high temperature oven to make the combination of the alloy with the alumina surfaces of the pearls.
  • the metallic coating of the friction surfaces consists of rings and metal sleeves which are crimped directly around the pearls or which are forced into their central orifice.
  • an advantageous variant of the invention consists in using said metal sleeves threaded into the central orifice of each pearl to constitute at the same time the intermediate pieces making the desired spacing between two consecutive pearls.
  • FIG. 2 there are also the main constituent elements of a coaxial cable according to the invention and the corresponding elements which bear the same reference numbers as in the previous example.
  • the intermediate pieces 4 are constituted by small cylinders 4 of stainless steel pierced along their axis with an orifice allowing the passage of the steel core 1 and are thus threaded onto said core 1 alternately with the pearls 2.
  • the edges 10 of the intermediate cylinders 4 as well as the outer edges 11 of the beads 2 have a rounded or hemispherical shape, since the presence of sharp angles would deteriorate the metallic coating deposited on the dielectric 2.
  • the different previous conditions mean that neither the intermediate pieces 4, nor the outer ringed tube 3 come into contact with the ceramic constituting the pearls 2. In this embodiment it may sometimes be desirable to divide the intermediate elements 4 into two parts to give more flexibility to the entire cable.
  • Fig.3 shows an embodiment of the second embodiment of the invention in which the metallic coating of the pearls 2 is constituted with respect to the external surface by a stainless steel ring 12 mounted hot or by any other known means on the dielectric and shown in more detail in FIG. 4; the metallic coating of the central orifices as well as the spacers 4 are produced using sheaths 13, one of which is more particularly shown in FIG. 5, the sleeves 13 being made of a stainless steel cylinder force-fitted at very low temperature (in liquid nitrogen for example) inside the central orifices 5 of the alumina beads 2.
  • the sleeves 13 are made of stainless steel and fitted after fitting the rings 12; they are drilled right through along their axis with an orifice 14 intended for the passage of the stainless steel core 1 of the coaxial cable (fig. 5).
  • the external electrode 3 is also constituted by a ringed tube made of stainless steel and each alumina pearl 2 is a disc pierced along its axis with a hole whose diameter is equal to the outside diameter steel sleeves 13.
  • Fig. 6 finally shows a very interesting variant of the invention in which we manage to further improve the electrical qualities of the cable while eliminating the intermediate parts.
  • the dielectric 2 the form of spherical balls or (ellipsoid ) alumina which are metallized on all their surface portions in contact with the core 1 or the braid 2 in stainless steel as well as the neighboring pearls.
  • four pearls 2a to 2d are shown, the first two 2a and 2b on the left side of the drawing are seen in section and the last two 2c and 2d on the right side, are seen from the front in elevation .
  • the metallized parts are shown in reinforced lines. This configuration, which is easier to manufacture because it requires only one component, offers, in addition to its antimicrophonic qualities, the advantage of eliminating any capacitive effect which occurs in the other variants between the metallized external faces of the intermediate pieces and the metal sheath.
  • a coaxial cable according to the invention was the subject of a comparative test with a cable of known type as shown in FIG. 1 in which the alumina beads had no protection particular metal on their surface part in connection with the core and the external braid.
  • the cable sample was placed in a shielded enclosure and rigidly fixed at two points.
  • a mechanical device gave the cable an alternating movement with an amplitude of 4 mm, the period of which was 2 seconds.

Landscapes

  • Communication Cables (AREA)
  • Insulated Conductors (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)

Claims (6)

1. Antimikrofonisches Koaxialkabel von der Art, welches in bekannter Weise zwischen der Seele (1) und der äußeren Beflechtung (3) ein Dielektrikum aufweist, welches aus mit hoher Dichte auf die Seele des Kabels aufgefädelten, keramischen Perlen (2) gebildet ist, dadurch gekennzeichnet, daß die gesamten Berühru.ngs- flächen zwischen den Perlen und der Seele, zwischen den Perlen und der äußeren Beflechtung und zwischen den aufeinander folgenden Perlen mit einem metallischen, leitfähigen Überzug versehen sind, wobei der Überzug insbesondere auf der Seele des Kabels vorhanden ist.
2. Koaxialkabel nach Anspruch 1, dadurch gekennzeichnet, daß der metallische Überzug der genannten Oberflächen aus einer Legierung von Molybden und Mangan gebildet ist.
3. Koaxialkabel nach Anspruch 1, dadurch gekennzeichnet, daß der metallische, leitende Überzug von Ringen (12) und metallischen Hülsen (13) gebildet ist, die auf die Perlen (2) aufgezogen sind.
4. Koaxialkabel nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß die Perlen (2a, 2b, 2c, 2d) Kugeln aus reinem Aluminiumoxyd sind, welche aneinanderstoßend auf die Seele (1) aufgefädelt sind und deren mit der Seele (1), der äußeren Umflechtung (3) und den benachbarten Perlen in Berührung stehenden Oberflächenbereiche metallisiert sind.
5. Koaxialkabel nach irgendeinem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß es eine gewisse Anzahl von metallischen Zwischenstücken (4) aufweist, die auf die Seele (1) aufgefädelt und zwischen jeweils aufeinanderfolgenden Perlen (2) angeordnet sind.
6. Koaxialkabel nach Anspruch 3, dadurch gekennzeichnet, daß die metallischen Hülsen unter Kraftwirkung in die Mittelöffnung (5) jeder Perle (2) eingeführt sind und gleichzeitig die Zwischenstücke bilden.
EP19790400610 1978-09-08 1979-09-04 Bei hoher Temperatur funktionsfähiges antimikrophonisches Koaxialkabel Expired EP0010461B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7825844 1978-09-08
FR7825844A FR2435787A1 (fr) 1978-09-08 1978-09-08 Cable coaxial antimicrophonique pouvant fonctionner a haute temperature

Publications (2)

Publication Number Publication Date
EP0010461A1 EP0010461A1 (de) 1980-04-30
EP0010461B1 true EP0010461B1 (de) 1983-08-24

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Family Applications (1)

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EP19790400610 Expired EP0010461B1 (de) 1978-09-08 1979-09-04 Bei hoher Temperatur funktionsfähiges antimikrophonisches Koaxialkabel

Country Status (3)

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EP (1) EP0010461B1 (de)
DE (1) DE2966090D1 (de)
FR (1) FR2435787A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE60210507T2 (de) * 2001-12-20 2007-04-05 Koninklijke Philips Electronics N.V. Rf system für ein mri apparat, versehen mit perlförmigen abstandshaltern
US6927332B1 (en) * 2004-03-22 2005-08-09 Motorola, Inc. Flexible test cable

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB397081A (en) * 1932-05-10 1933-08-17 Telefunken Gmbh Improvements in or relating to electric cables for use for conveying radio and other very high frequency energy
DE702951C (de) * 1932-12-21 1941-02-20 Porzellanfabrik Kahla solierten Hochfrequenzkabeln

Also Published As

Publication number Publication date
FR2435787B1 (de) 1981-11-06
DE2966090D1 (en) 1983-09-29
EP0010461A1 (de) 1980-04-30
FR2435787A1 (fr) 1980-04-04

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