US3303376A - Triggered vacuum gap device employing gas evolving electrodes - Google Patents

Triggered vacuum gap device employing gas evolving electrodes Download PDF

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Publication number
US3303376A
US3303376A US510562A US51056265A US3303376A US 3303376 A US3303376 A US 3303376A US 510562 A US510562 A US 510562A US 51056265 A US51056265 A US 51056265A US 3303376 A US3303376 A US 3303376A
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United States
Prior art keywords
electrodes
trigger
gap
arc
electrode
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Expired - Lifetime
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US510562A
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English (en)
Inventor
James M Lafferty
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General Electric Co
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General Electric Co
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Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US510562A priority Critical patent/US3303376A/en
Priority to GB47598/66A priority patent/GB1129704A/en
Priority to DE19661640190 priority patent/DE1640190A1/de
Priority to JP7860266A priority patent/JPS45020649B1/ja
Priority to ES0333986A priority patent/ES333986A1/es
Priority to FR85582A priority patent/FR1502480A/fr
Application granted granted Critical
Publication of US3303376A publication Critical patent/US3303376A/en
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    • 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
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/02—Details
    • H01J17/14—Magnetic means for controlling the discharge
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/02—Details
    • H01J17/22—Means for obtaining or maintaining the desired pressure within the tube
    • H01J17/26—Means for producing, introducing, or replenishing gas or vapour during operation of the tube
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0059—Arc discharge tubes

Definitions

  • the present invention relates to improved vacuum gap devices and particularly those of the triggered. vacuum gap and triggered vacuum switch type which are adapted to operate on alternating or unidirectional voltages.
  • Vacuum switches and vacuum gaps have recently been brought to a stage of great commercial and technological importance.
  • the fundamental improvement which has greatly increased the versatility and the usefulness of such devices constitutes means for accurately and repetitively controlling, with great speed, the breakdown of such devices.
  • I accomplish this by providing a trigger electrode assembly associated with the cathode electrode of the switching device for instantaneously and with great speed and accuracy establishing therein a high current arc between a pair of primary electrodes disposed therein so as to define a breakdown gap.
  • an object of the present invention to provide improved vacuum gap devices having structure which uniquely adapts the same for use with alternating current voltages while, at the same time, not rendering the device as inoperable with unidirectional current voltages.
  • a vacuum gap device including a pair of primary electrodes defining therebetween a vacuum gap. These electrodes are located within an evacuated envelope, which envelope is composed partially of metal and at least in part of the high voltage insulating substance so as to provide electrical isolation between the primary electrodes to prevent short-circuiting of the gap defined thereby.
  • both electrodes may be fixed electrodes defining a fixed gap.
  • one electrode may be attached to a suitable vacuum-tight bellows which permits relative motion between the two electrodes so as to allow the gap to be manually operable and or reclosable.
  • trigger electrode assemblies are located within central apertured portions of each electrode and are connected so as to cause the injection of a highly ionized gaseous plasma into the gap between the main or primary electrodes by causing a sprak discharge and the generation of a gaseous plasma between the electrode which is energized as cathode and the associated trigger electrode.
  • FIGURE 1 is a vertical cross-sectional view of a fixed gap triggerable vacuum gap device constructed in accord with the present invention
  • FIGURE 2 is a vertical cross-sectional view of a trigger electrode utilized in the device of FIGURE 1, and
  • FIGURE 3 is a vertical cross-sectional view of an alternative embodiment of the invention. '1
  • the vacuum gap device of FIGURE 1 includes an envelope represented generally as 1 containing therein is symmetrical along the longitudinal axis thereof, a first flanged metallic end piece 11 having a central aperture therein and a second flanged metallic apertured end plate. 12, also having a central aperture therein, said end pieces being disposed at opposite ends to define with cylindrical A pair of substantiallyv cylindrical centrally apertured insulated bushings 13 and 14 each ofW'hich has a large outside diameter portion,
  • apertures within insulated bushings 13 and 14 are closed by the insertion therewithin of annular cylindrical electrode support members 15 and 16 respectively.
  • the interior of cylindrical electrode support members 15 and 16 are hollow and sealed to vacuum by the insertion therein and sealing thereto of trigger electrode assemblies 5. and 6 respectively.
  • Each of the cylindrical apertures in bushings 13 and 14 are slightly larger than the outside diameter of electrode support members 15 and 16 for added insulation properties and to provide an insulator surface not likely to be short-circuited by condensed metal vapor.
  • the vacuum seal is made between these members by brazing thereto of annular seal members.
  • URE 1 may typically be as follows:
  • Main envelope member 9 may be fabricated from a metal which will withstand high temperatures and which possesses sul'ficiently physical strength as to constitute the outside body of the.-
  • Flanged end plate members 11 and 12 and flanged seal members 17 and 18 are typically comprised of a material which makes good vacuum-tight seals to ceramic bushings 13 and 14 and to metallic members 9, 15, and 16 respectively and may conveniently be a Fernico or Kovar alloy generally utilized in electric discharge devices of this nature for this purpose.
  • Bushings 13 and 14 are comprised of a high temperature gas impermeable'ceramic material as for example high density alumina (94% or higher A1
  • Electrode support members 15 and 16 are preferably comprised of a highly conductive, substantially gas free material as for example OFHC copper, premium grade. No special precautions need to be taken to render this material gas-free, other than vacuum firing prior to assembly.
  • Primary electrodes 2 and 3 are composed of a high ly purified copper or high vapor pressure material as for example any of the materials set forth in Lee and Cobine Patent No. 2,975,256, issued March 14, 1961. This material is rendered substantially free of all gas and'gas forming compounds by some refining technique'as for example that set forth in copending application Serial No. 146,245, filed October 19, 1961, now Patent No. 3,234,- 351, of M. HgHebb, so as to reduce the concentration of gas and gasforrning impurities therein to a figure of less than 1 part in The trigger electrode assemblies 5 and 6 of FIGURE 1 of the drawing are illustrated in greater detail in vertical crosssection in FIGURE 2 of the drawing.
  • a typical figure represented generally as 20 comprises a hollow cylindrical metallized ceramic base member 22 which has a narrow circumferential groove 23 out therein, which may be tapered as shown, near the inward extremity thereof.
  • Means for sealing the trigger electrode in a vacuum-tight seal to the interior of the electrode support member are provided in the form of an annular flanged member 24 having an extended shoulder and an aperture collar member 25 which rests thereupon and is sealed thereto.
  • Both of these members are conveniently constructed of a metal suitable for making metal-to-seal ceramic seals as for example one of the general classes of metal alloys known as Fernico or Kovar.
  • the smallest inner diameter surface of cylindrical member 26 makes electrical contact with metallized ceramic cylindrical member 22.
  • a second cylindrical sleeve 30 which is likewise beveled at one of its ends to match upper bevel of the groove 23 in cylindrical member 22, slides over ceramic member 22 and is aligned with the upper bevel of groove 23 therein.
  • a metallic cap and shield piece 31 having a re-entrant portion 32 and a central aperture 33 rests upon the upper end of cylindrical membert22 and within the interior end of second sleeve member 30.
  • a trigger lead wire 34 enters the central aperture within'ceramic trigger support member 22 and is aflixed to the re-entrant end cap 31 at the uppermost portion thereof.
  • Thislead may conveniently be of molybdenum or any'other low vapor material conventionally utilized providing lead wires in electric discharge devices.
  • Members 24 and 25 are conveniently selected as a Fernico, or Kovar equivalent metal or alloy.
  • the remaining metallic members 26, 29, 30, and 31 may conveniently be selected as a refractory metal, as for example, tungsten or molybdenum.
  • the portions of metallic sleeve members 29 and 30 which are to be exposed between the upper portions of cylindrical shield member 26 and cylindrical end cap and shield member 31 are preferably coated with a material as for example a hydride of titanium, zirconium, hafnium, yttrium, erbium or other rare earth metals, which hydrides serve as a source of ionizable gas which may be emitted upon the initiation of a voltage pulse between sleeve members 29 and 30.
  • a material as for example a hydride of titanium, zirconium, hafnium, yttrium, erbium or other rare earth metals, which hydrides serve as a source of ionizable gas which may be emitted upon the initiation of a voltage pulse between sleeve members 29 and 30.
  • the device of FIGURE 1 may be fabricated in accord with standard ceramic and metal tube technology in which case thetrigger assemblies are independently fabricated and independently sealed to the respective electrode support members 15 and 16.
  • the electrode support members, the apertured insulator bushings, and the primary electrodes are then assembled and sealed leaving only plug 35 unsealed.
  • the device is then placed in an outgassing furnace and raised to a temperature of for example 850 C. and held at this temperature for one or two hours in order to cause outgassing and the removal of sorbed gasses from all of the constituent parts thereof. After sufficient outgassing and while the device is still at an elevated temperature, a suitable pressure of an active, ionizable gas as for example hydrogen, is introduced through plug 35 and the device is sealed.
  • an active, ionizable gas as for example hydrogen
  • a reservoir for an active gas as for example hydrogen
  • a gettering material 37 as for example titanium, which is appropriately shielded, as for example, by bafiles from the direct lineof-sight with the region in-which the primary arc is active, so that the device may continue for many arcing operations without loss of hydrogen pressure.
  • the sealing operation may be carried out in a furnace charged with'an active gas, as for example a hydrogen furnace at one atmosphere pressure, in which case enough active, gas storing reservoir material, asfor example titanium, to absorb substantially all of the hydrogen vapor cooling and establish a pressure of 10- torr or less.
  • FIGURE 1 of the drawing electrical connections for operation of the triggered vacuum gap device are made schematically, indicating the connection of the primary electrodes, through the electrode support members to the line voltage or to the high which is to be switched or interrupted as the case may be.
  • the potential of each of electrodes 2 and 3 will therefore bear a predetermined but varying relation to ground potential.
  • Each of the trigger electrodes assemblies 5 and 6 are connected to a grounded pulse source 36.
  • the gap is broken down by the establish ment of first a spark discharge across the trigger gap which causes a triggering arc to be struck between the triggering electrode and the cathode member.
  • the electrode which is the cathode for one operation may be the anode upon the next operation. Accordingly, it is desirable and necessary in accord with the present invention that they trigger electrode assembly and pulse source be such that the primary gap is broken down by an appropriate starting arc irrespective of which electrode is cathode. It is for this reason that, in
  • I provide a trigger electrode assembly associated with each of the main electrodes.
  • it is possible to cause a breakdown irrespective of which electrode is cathode.
  • This arrangement gives greater flexibility to the applicability of the triggered vacuum gap device in accord with the present invention and makes the external circuitry exceedingly simple, particularly as compared with the various polarity inversion circuits which might be required if only one trigger electrode were present.
  • a pulse source is provided which strikes a triggering are only with respect to the cathode, although it is feasible that the device could be operated with a pair of simultaneous trigger arcs.
  • a short electrical pulse which may vary in magnitude from 50 volts to 5000 volts depending upon the con-figuration of the device and the magnitude of currents to be interrupted is generated in pulse source 36 which may be any conventional pulse generating means, well known to the electronics arts.
  • the pulse generated in pulse source 36 is a voltage which has a particular reference to ground potential since the pulse source is grounded. This pulse is applied to both trigger electrodes 5 and 6 through electrical conductors 38 and 39 which are connected to trigger electrode terminals 34 and 40.
  • the mechanism of breakdown of the primary gap of the vacuum gap device in accord with the present invention is substantially as follows: With the connection of primary electrodes 2 and 3 to the source of high voltage a high electric field is established within gap 4. When, because of a high voltage transient which could damage the equipment which may be protected by a device of this nature, or in accord with a preselected timing pulse for interrupting the main power, a preselected voltage pulse which is positive with respect to ground potential is generated from pulse source 36 and applied to electrode assemblies 5 and 6 respectively. As illustrated in FIG- URE 2, this voltage pulse is applied through conductor 34 and end cap 31 to one cylinder 30 bounding gap 23. The other side of the gap is connected through cylinder 29, counterbored member 26 and flange 25 to the primary electrode.
  • While a simple grounded pulse source has been described herein there are other suitable and functionally equivalent circuit connections which may be utilized, depending upon the type circuit in which the device is to be connected.
  • One such modification contemplates a separate pulse source connected to the trigger electrode lead 34 and 40 respectively of each of the trigger electrode assemblies 5 and 6. These pulse sources would then be dependent for actuation upon a secondary pulse source which would feed a signal identical in magnitude and phase into each of the pulse sources so that the pulse sources would each generate a pulse at identically the same time.
  • FIGURE 3 is an alternative embodiment to the device of FIGURE 1 and wherein like parts are identified with the same reference numerals.
  • arc-electrode 2 is rendered reciprocably movable into, and out of, contact with arcelectrode 3 by means of bellows 41 which is hermetically sealed between bushing 13 and arc-electrode support member 15.
  • Triggerable vacuum gap apparatus comprising an envelope evacuated to a pressure of 10 mm. Hg or less; a pair of arc-electrodes disposed within said envelope in electrically insulated relationship and defining therebetwee-n a primary discharge gap; a trigger assembly associated with each of said arc-electrodes and containing means for storing an ionizable gas and spark gap means adjacent said first named means for releasing said ioniza'ble gas by the initiation of a spark discharge upon receipt of a suitable trigger pulse; means applying electrical potentials to each of said arc-electrodes, each of said potentials having a predetermined relationship to ground potential; and pulse source means associated with said trigger assemblies for applying a triggering pulse which is independent of the potentials applied to said arc-electrodes and positive with respect to ground potential to said trigger assemblies to cause only one of said trigger assemblies to be activated at any given time to cause the breakdown of said primary gap with the arc-electrode associate-d with the activated trigger assembly

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  • Gas-Filled Discharge Tubes (AREA)
  • Air Bags (AREA)
  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
  • Plasma Technology (AREA)
US510562A 1965-11-30 1965-11-30 Triggered vacuum gap device employing gas evolving electrodes Expired - Lifetime US3303376A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US510562A US3303376A (en) 1965-11-30 1965-11-30 Triggered vacuum gap device employing gas evolving electrodes
GB47598/66A GB1129704A (en) 1965-11-30 1966-10-24 Triggered vacuum gap device
DE19661640190 DE1640190A1 (de) 1965-11-30 1966-11-30 Schalteinrichtung mit steuerbarer Vakuum-Schaltfunkenstrecke
JP7860266A JPS45020649B1 (sv) 1965-11-30 1966-11-30
ES0333986A ES333986A1 (es) 1965-11-30 1966-11-30 Un aparato disparable con distancia disruptiva en vacio.
FR85582A FR1502480A (fr) 1965-11-30 1966-11-30 Dispositif de commutation sous vide

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US510562A US3303376A (en) 1965-11-30 1965-11-30 Triggered vacuum gap device employing gas evolving electrodes

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US3303376A true US3303376A (en) 1967-02-07

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US510562A Expired - Lifetime US3303376A (en) 1965-11-30 1965-11-30 Triggered vacuum gap device employing gas evolving electrodes

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US (1) US3303376A (sv)
JP (1) JPS45020649B1 (sv)
DE (1) DE1640190A1 (sv)
ES (1) ES333986A1 (sv)
FR (1) FR1502480A (sv)
GB (1) GB1129704A (sv)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3450922A (en) * 1966-08-03 1969-06-17 Gen Electric Triggerable vacuum gap having offset trigger
US3465192A (en) * 1966-09-21 1969-09-02 Gen Electric Triggerable arc discharge devices and trigger assemblies therefor
US3480821A (en) * 1967-12-18 1969-11-25 Gen Electric Stabilized vacuum gap device with elementary electrode structure
US4232352A (en) * 1977-07-19 1980-11-04 Tokyo Shibaura Denki Kabushiki Kaisha Protective gap devices for protecting circuit breakers
US4978893A (en) * 1988-09-27 1990-12-18 The United States Of American As Epresented By The United States The Department Of Energy Laser-triggered vacuum switch
US5233143A (en) * 1991-11-06 1993-08-03 The United States Of America As Represented By The Secretary Of The Navy High-power gas switch with hydride electrodes
WO2012005865A1 (en) * 2010-06-29 2012-01-12 Schneider Electric USA, Inc. Arcing fault and arc flash protection system having a high-speed switch

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2128884A (en) * 1934-10-25 1938-08-30 Marx Erwin Arc converter
US2508954A (en) * 1943-02-03 1950-05-23 Merlin Gerin Electric discharge device with auxiliary electrode
US2740915A (en) * 1954-10-18 1956-04-03 Jennings Radio Mfg Corp Adjustable spark gap
US3087092A (en) * 1961-05-10 1963-04-23 Gen Electric Gas generating switching tube

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2128884A (en) * 1934-10-25 1938-08-30 Marx Erwin Arc converter
US2508954A (en) * 1943-02-03 1950-05-23 Merlin Gerin Electric discharge device with auxiliary electrode
US2740915A (en) * 1954-10-18 1956-04-03 Jennings Radio Mfg Corp Adjustable spark gap
US3087092A (en) * 1961-05-10 1963-04-23 Gen Electric Gas generating switching tube

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3450922A (en) * 1966-08-03 1969-06-17 Gen Electric Triggerable vacuum gap having offset trigger
US3465192A (en) * 1966-09-21 1969-09-02 Gen Electric Triggerable arc discharge devices and trigger assemblies therefor
US3480821A (en) * 1967-12-18 1969-11-25 Gen Electric Stabilized vacuum gap device with elementary electrode structure
US4232352A (en) * 1977-07-19 1980-11-04 Tokyo Shibaura Denki Kabushiki Kaisha Protective gap devices for protecting circuit breakers
US4978893A (en) * 1988-09-27 1990-12-18 The United States Of American As Epresented By The United States The Department Of Energy Laser-triggered vacuum switch
US5233143A (en) * 1991-11-06 1993-08-03 The United States Of America As Represented By The Secretary Of The Navy High-power gas switch with hydride electrodes
WO2012005865A1 (en) * 2010-06-29 2012-01-12 Schneider Electric USA, Inc. Arcing fault and arc flash protection system having a high-speed switch
US8319136B2 (en) 2010-06-29 2012-11-27 Schneider Electric USA, Inc. Arcing fault and arc flash protection system having a high-speed switch
CN103026445A (zh) * 2010-06-29 2013-04-03 施耐德电气美国股份有限公司 具有高速开关的闪弧故障和电弧闪光保护系统
CN103026445B (zh) * 2010-06-29 2016-10-26 施耐德电气美国股份有限公司 具有高速开关的闪弧故障和电弧闪光保护系统

Also Published As

Publication number Publication date
DE1640190A1 (de) 1970-12-03
GB1129704A (en) 1968-10-09
JPS45020649B1 (sv) 1970-07-14
ES333986A1 (es) 1967-10-16
FR1502480A (fr) 1967-11-18

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