Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T1/00—Details of spark gaps
  • H01T1/20—Means for starting arc or facilitating ignition of spark gap
  • H01T1/22—Means for starting arc or facilitating ignition of spark gap by the shape or the composition of the electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T2/00—Spark gaps comprising auxiliary triggering means
  • H01T2/02—Spark gaps comprising auxiliary triggering means comprising a trigger electrode or an auxiliary spark gap
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T4/00—Overvoltage arresters using spark gaps
  • H01T4/10—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel
  • H01T4/12—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel hermetically sealed
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T4/00—Overvoltage arresters using spark gaps
  • H01T4/04—Housings

Definitions

• the invention relates to a switching spark gap capable of transferring in a fraction of a second a current of very high intensity at very high voltage between its electrodes, and more particularly such a spark gap comprising two coaxial electrodes passing through the end-to-end spark gap.
• the switching spark gaps are generally used in applications such as the Marx generator or other very high voltage mounting, for example in combination with capacitors for storing electrical energy, and to restore it in the form of a current of very high intensity under very high voltage.
• document EP 1 629 577 discloses such a spark gap comprising two elongated electrodes facing each other between which an electric arc develops, the triggering of the electric arc being able to take place by exceeding a threshold of voltage between the electrodes or by applying a voltage on a trip electrode.
• the gaps such as that mentioned above are of a complex internal organization because of the third trigger electrode. When used with a trigger by exceeding a threshold of self-priming of the spark gap, they are difficult to adjust.
• the present invention aims to provide a switching spark gap that is simple to perform, allowing optionally an easy adjustment of the trigger voltage.
• the invention also aims to provide such a spark gap that is simple to associate with capacitors connected in parallel.
• the invention also aims to provide such a spark gap in which the wear of the electrodes is minimized.
• the invention also aims to provide such a spark gap whose size is reduced for the same switching power.
• the invention relates to a switching spark gap comprising at least a first electrode and a second electrically conductive electrode each having an arc zone placed facing the arc zone of the other electrode, the electrodes being adapted to be connected to the terminals of a source of potential, characterized in that the spark gap has a generally tubular shape, said first electrode forming a cylindrical body of the spark gap, open at both ends and said second electrode, said central electrode , cylindrical and coaxial with the first having an electrical continuity over its entire length and extending in the axis of the spark gap at least from one end to the other of the cylindrical body.
• the spark gap is connected so that the positive pole of the voltage generator supplying the mounting is connected to the central electrode of the spark gap and reference is made to this electrode as well. than to its connected elements under the term anode or anodic.
• the cylindrical body of the spark gap is connected to the negative pole of the voltage generator and refers to this electrode and its connected elements under the term cathode or cathode.
• the central electrode is kept at a distance from the body of the spark gap by at least one sleeve comprising an insulator traversed by the central electrode.
• a sleeve of outside diameter substantially equal to the inside diameter of the body allows to center thereon an insulator made of dielectric material, itself traversed by the central electrode.
• Other sleeves may be provided, depending on the length of the central electrode, to maintain it coaxially with the body.
• At least one of said sleeves is movable relative to the body of the spark gap along the axis thereof.
• the displacement of the sleeve allows, if necessary, to move the central electrode along the axis of the spark gap.
• one of said sleeves comprises a liner electrically connected to the body of the spark gap to form the arc zone of the body.
• the central electrode comprises a lining adapted to form the arc zone of the central electrode.
• a copper and tungsten alloy gasket may be mounted on the center electrode, facing the gasket connected to the body, to form the arc zone of the central electrode.
• the arc zones are coaxial surfaces of revolution between them and of axis coinciding with the axis of the spark gap.
• an electric arc formed between the arc areas has a substantially radial direction with respect to the axis of the spark gap and the magnetic field related to the arc current drives it in a rotational movement around the axis of the spark gap, thus avoiding premature wear of a particular point of the arc zone.
• the shape of the arc zones is adapted so that an air gap between the arc zones is variable as a function of the respective position of each mobile sleeve.
• the air gap arranged between these edges has a minimum value when these edges are in the same transverse plane and increases when the axial distance between the plane of each edge increases.
• the spark gap comprises two sleeves defining between them a space, called the firing space, inside which are located the arc zones of the two electrodes.
• the central electrode and held by two ice sleeves substantially at each end of the cylindrical body.
• the lining forming the arc zone of the central electrode is placed between the two sleeves, and one of the two sleeves carries the liner connected to the body of the spark gap, facing the lining of the central electrode.
• the sleeves are provided with sealing means for filling the firing space with a gas under pressure.
• sealing means for filling the firing space with a gas under pressure.
• the central electrode is fixedly mounted relative to one of the sleeves and sliding relative to the other.
• the two sleeves are sliding relative to the body of the spark gap.
• One of the sleeves carries the liner in contact with the body of the spark gap and the central electrode is fixedly mounted relative to the other sleeve.
• connection means adapted to cooperate with conjugated connection means carried by other coaxial components.
• connection means adapted to cooperate with conjugated connection means carried by other coaxial components.
• the invention also relates to a switching spark gap characterized in combination by all or some of the characteristics mentioned above or below.
• FIG. 1 is a sectional view of a spark gap according to the invention
• FIG. 2 shows a detail of the firing space of a spark gap according to the invention.
• FIG. 1 shows a sectional view of the spark gap 1 according to the invention.
• the spark gap 1 comprises a first electrode 2 forming a cylindrical body 3 made of conductive material.
• the choice of material depends on the conditions of use of the spark gap 1 and can be left to the appreciation of the person skilled in the art among most metals such as copper, aluminum, stainless steel or not, possibly coated with protective layers (nickel, etc.).
• a second electrode or central electrode 4 extends coaxially and in the center of the body 3.
• the central electrode 4 comprises, starting from the right of FIG. 1, a connection pin 14 screwed or mounted in force to the interior of a cylindrical connecting piece inserted in an insulator 10, for example ceramic, glass, resin or any other material having suitable dielectric characteristics.
• the insulator 10 has a substantially cylindrical shape having on its outer face a series of radial corrugations to increase the electrical path, as known in the art of insulators.
• the insulator 10 is traversed by a rod 21 screwed on the one hand into the connection piece 20 and on the other hand into a cylindrical electrode support 22.
• the connection piece 20 has a seal at the interface with the insulator 10 so as to provide a sealed passage therethrough.
• the electrode support 22 carries a lining 5 of at least partly cylindrical shape of revolution.
• the liner 5 is made of a material particularly adapted to withstand arcing, for example a copper alloy and tungsten.
• a second conductive rod 16 passes through a second insulator 12, of a shape similar to that of the insulator 10, and connects the electrode support 22 to a contact socket 17 screwed or mounted in force in a second cylindrical connecting piece 23 inserted in leaktight manner at the end of the insulator 12.
• the second connection piece 23 also comprises a bore inside which a connection bushing 15 is fixed.
• the internal diameter of the connection bushing 15 is adapted to cooperate with the outer diameter of a pin connection similar to the pin 14 so as to make a connection by interlocking with a coaxial capacitor (not shown) having such a pin.
• the rod 16 is slidably mounted inside the insulator 12 and the contact sleeve 17 so as to allow a relative longitudinal movement between the insulator 10 inside which the central electrode 4 is mounted so that fixed and insulator 12.
• This sliding assembly also allows to decouple in rotation the two insulators.
• the central electrode 4 thus has an electrical continuity of the connection sleeve 15 at one end of the cylindrical body 3 to the connection pin 14 at the other end.
• the insulator 10 is fixed on a sleeve 11 which holds it in a coaxial position centered with respect to the cylindrical body 3.
• the sleeve 11 is adapted to be movable relative to the body 3, for example by means of an external thread cooperating with a corresponding thread internal to the body 3. Seals 18 between the body 3 and the sleeve 11 and a seal 19 between the insulator 10 and the sleeve 11 allow for a sealed barrier inside the body 3.
• the insulator 12 is mounted on a sleeve 13 adapted to be movable relative to the body 3 and to form a sealed barrier on either side of the sleeve 13.
• the two sleeves and their respective insulators thus form between them a sealed space, called the firing space 24, inside which is located the packing 5 of the central electrode 4.
• the sleeves 11 and 13 are preferably metallic, therefore electrically conductive, for reasons of mechanical strength but may be provided in any other material, conductive or not, having a mechanical strength appropriate.
• the sleeve 13 further comprises a cylindrical extension parallel to the body 3 extending inside the firing space 24, towards the sleeve 11.
• a lining 8 in a material similar to that of the lining 5, and of substantially cylindrical shape is fixed at the end of this extension of the sleeve 13.
• This lining 8 is in electrical contact with the body 3 on the one hand through the sleeve 13 if it is metallic but also by tongues contact 9 fixed on the lining 8 and rubbing on the inside of the body 3, thus achieving a lower resistance electrical continuity and better reliability.
• FIG. 2 shows a detail view of a portion of the shooting space 24 inside which are shown the liners 5 and 8 respectively connected to the central electrode 4 and the body 3.
• the outer surface of the liner 5 is placed facing the inner surface of the liner 8 and outside thereof.
• the rounded portion of the outer surface of the gasket 5 located at the intersection between its orthogonal face and the axis of the spark gap and its cylindrical periphery is the portion of the central electrode 4 closest to the gasket 8 and forms thus an arc region 6 of the central electrode 4.
• the rounded portion of the surface of the gasket 8 facing the arc zone 6 of the central electrode 4 forms the arc zone 7 of the body 3.
• the minimum distance between arc areas 6 and 7 forms an air gap e.
• Arc areas 6 and 7 are surfaces of revolution, coaxial with each other and axis coincident with that of the spark gap, so the air gap e is constant regardless of the radial direction considered.
• the length of this air gap, the pressure and the nature of the gas occupying the firing space 24 determine the starting voltage of the spark gap.
• an electric arc is formed between the arc zones and transfers an electric charge accumulated in one or more charging devices such as capacitors (not shown) connected in parallel with the spark gap.
• the air gap e being constant whatever the radial direction, the point of initiation of the arc is random on the perimeter of the arc zones and the magnetic field generated by the electric arc force it to circulate around the axis of the spark gap. In this way, the wear of the linings is homogeneous and reduced.
• the starting voltage of the spark gap according to the invention is advantageously adjustable by acting on the length of the gap e, for example by moving longitudinally one or the other of the two sleeves along the axis of the spark gap .
• the two sleeves will be moved concomitantly to minimize the movement of the pin 14 and the connection socket.
• connection of the body 3 of the spark gap with the body of charging devices coaxially mounted with the spark gap 1 can be achieved by any means known to those skilled in the art, for example by flanges, bushes, etc.

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (5)

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Family Cites Families (8)

• 2012
  • 2012-12-07 FR FR1261756A patent/FR2999350B1/fr not_active Expired - Fee Related
• 2013
  • 2013-12-05 WO PCT/EP2013/075701 patent/WO2014086939A1/fr active Application Filing
  • 2013-12-05 US US14/650,098 patent/US9466950B2/en active Active
  • 2013-12-05 CA CA2894010A patent/CA2894010C/fr active Active
  • 2013-12-05 EP EP13801576.3A patent/EP2929604B1/de active Active

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