US3611013A - Breakdown potential control assembly for gas flow-through electrical discharge device - Google Patents

Breakdown potential control assembly for gas flow-through electrical discharge device Download PDF

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Publication number
US3611013A
US3611013A US9562A US3611013DA US3611013A US 3611013 A US3611013 A US 3611013A US 9562 A US9562 A US 9562A US 3611013D A US3611013D A US 3611013DA US 3611013 A US3611013 A US 3611013A
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United States
Prior art keywords
anode
cathode
gas
opening
electrodes
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Expired - Lifetime
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US9562A
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English (en)
Inventor
Charles Herbert Gleason
George K Yamasaki
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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Publication date
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    • 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

Definitions

  • the present invention relates to electrical discharge devices in which a circulating gas medium is provided within the device. In such structures, it is normally desired that a low breakdown potential exists between a selected portion of the electrode configuration within the gas medium while the remaining portion of the configuration is such that the breakdown potential is substantially higher than the selected portron.
  • the breakdown potential versus pressure 1 distance relationships for various gases and mixtures are generally known and described by a family of curves called the Paschen curves. A typical curve is shown in FIG. I of the drawing.
  • the Paschen curve indicates that the breakdown will occur most readily at a specific value of pressure x distance and higher voltages are necessary to initiate electrical breakdown asthe product ;of pressure .1:
  • the desired breakdown surface region operates near the minima of the Paschen curve and the remaining structure normally will operate to the left of the minima.
  • a decrease in pressure or spacing results in a higher breakdown potential as to the remaining surfaces of the device which is of course the desired result.
  • a pressure gradient will form between the input and the exit of the gas system.
  • the pressure between the electrodes of the device is dependent on the dimensions of spacing. The increase of spacing between the electrodes will attain a more efficient pumping speed and hence lower values of pressure but the increase in spacing will reduce breakdown potential.
  • This invention relates to an electrical discharge device utilizing a gas flow medium in which a member of sufficient permeability is utilized between two electrode members of different potential to permit easy pumping of the gas medium but sufficiently impermeable to still maintain the desired distance spacing and low breakdown by means of the porous member positioned therebetween.
  • FIG. I is a graphic illustration of a Paschen-curve Pd versus breakdown potential for a suitable circulating gas medium such as Argon;
  • FIG. 2 is a sectional view of a glow discharge type device incorporating the teachings of this invention.
  • FIG. 3 is another view of FIG. 2 illustrating the invention.
  • the device includes an anode l0, and a cathode 20.
  • the anode comprises a block 12 of a suitable electrically conducting material such as brass having a central opening 14 therein.
  • An anode extension 16 is also provided which extends downwardly and is tubular in cross section.
  • the central opening I4 is closed off at the upper portion of the anode by a window 18 and the window 18 is vacuum sealed to the anode block I2.
  • the central openingl4 includes the opening in the anode extension 16.
  • a tubular conduit or opening 22 is provided in the anode block 12 to introduce a suitable gas into the central opening 14.
  • annular groove 24 is provided on the lower surface of the anode block 12 surrounding the tubular extension I6 andthe central opening 14.
  • the annular groove or cavity 24 is provided with a conduit 26 for exhausting or pumping out the gas fromthe device.
  • a suitable gas such as argon is continually circulated throughthe device by means of a suitable pumping means.
  • the cathode 20 is an annular member, 30 of a suitable electrically conductive material such as brass which is provided with a central opening 32 and into which the anode extension 16 is inserted.
  • the spacing between the outer surface of the I tubular extension 16 and the inner surface of the opening 32 is about 0.010 inch even though the spacing can be more or less depending on desired pumping rate and gas flow.
  • the cathode 20 is positioned and spaced from the anode 12 by a suitable insulating spacer 34.
  • the pressure in the systems might vary from 2 to 20 torr with a gradient through the system.
  • the pumping cavity 24 is provided with a gas permeable member 36 in the form of a mesh of a suitable electrically conductive material such as brass or stainless steel or anyiother suitable conducting material.
  • the mesh 36 has a mesh opening of about 0.010-0.100 inch and a wire diameter of about 0.0l00.l00 inch.
  • the member 36 is positioned to shield the inner surface of the cavity 24 within the anode block 12 from the'cathode 20.
  • the member 36 permits the enhanced pumping speed of the gas through the device'while maintaining the distance d between the cathode 20 and the anode 10.
  • porous plug plate, screening, or perforated plate members composed of materials of good electn cally conductive materials or of lesser electrical conductivity such as insulators andsemiconductors coated with suitable electrically conductive films or coatings.
  • the member 36 is also not restricted to the flat parallel configuration illustrated but may take on other physical configurations such as cylindrical or circular.
  • the cathode 20 is provided with a flat platelike member 40 on which a sample material 42 is provided, and the plate member 40 is sealed to the cathode block 20 by means of an O-ring type seal.
  • the sample also may be the block 40 itself or an ingot or any slug with a flat surface.
  • the desired area of discharge is located in the area of the location of the sample material 42 and glow emission is emitted from this area and the region within the tubular extension The light is emitted through the window I8.
  • a typical voltage is supplied betweenthe cathode 20 and anode I0 by means of a power supply 44 and a typical voltage is about 200-3000 v.
  • the electrode 36 may operate at any suitable potential.
  • the electrode 36 is connected to the anode 10. It could'also operate at cathode potential.
  • the device is made to provide electrical breakdown'inthe region of the sample material 42 substantially near the minimum of a curve illustrated in FIG. I.
  • the breakdown potential is maintained to the left side of the minimum portion of the curve and at a higher breakdown potential.
  • the breakdown potential without the mesh electrode 36 might be of about 900 volts while the insertion of the mesh electrode 36 positioned at a distance from the cathode 20 of about 0.070 inch was such as to provide a breakdown potential of 2,800 volts.
  • a glow discharge device comprising a first electrode and a second electrode, said first and second electrodes spaced apart and insulated from each other, said first and second electrodes comprising first portions between which an electric discharge is desired and second portions between which a discharge is undesired, means for circulating gas between said first and. second electrodes, a gas permeable electrode positioned between said second portions of said first and second electrodes to permit a high circulating rate of said gas between said first and second electrodes while providing breakdown potential protection between said second portions of said first and second electrodes.
  • a glow discharge device comprising a cathode and anode and spaced apart, means for circulating a gas between said cathode and anode, said cathode having a centrally located opening, said anode having a tubular extension portion extending into said opening, the active portion of said cathode wherein an electrical discharge is formed to said anode positioned at the opposite end of said opening with respect to said anode and facing the end portion of said tubular extension of said anode and a gas permeable electrode positioned between a part of the inactive portion of said cathode wherein an electrical discharge is undesired and said anode to permit circulation of said gas while increasing the breakdown potential between said anode and said inactive portion of saidcathode.
  • said cathode member is an annular member having a surface facing a surface of said anode, an annular cavity defined between a portion of said surface of said cathode and a portion of said surface of said anode and said permeable electrode member positioned within said annular cavity.

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US9562A 1970-02-09 1970-02-09 Breakdown potential control assembly for gas flow-through electrical discharge device Expired - Lifetime US3611013A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US956270A 1970-02-09 1970-02-09

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US (1) US3611013A (enExample)
DE (1) DE2105182A1 (enExample)
FR (1) FR2078263A5 (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4367427A (en) * 1979-03-03 1983-01-04 Vacuumschmelze Gmbh Glow discharge lamp for qualitative and quantitative spectrum analysis

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3087113A (en) * 1961-01-23 1963-04-23 Beckman Instruments Inc Detector for gas chromatography
GB967047A (en) * 1962-04-27 1964-08-19 Kloeckner Werke Ag Spectrometric analysis
US3188180A (en) * 1961-05-09 1965-06-08 Huettenwerk Oberhausen Ag Process for the extraction of gases from metals
US3361907A (en) * 1962-12-06 1968-01-02 Nat Res Dev Apparatus for gas analysis having voltage means to accelerate electrons from an ionization chamber to a detection chamber
US3378725A (en) * 1964-04-15 1968-04-16 Beckman Instruments Inc Electron capture detector having separate ionization and sensing regions

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3087113A (en) * 1961-01-23 1963-04-23 Beckman Instruments Inc Detector for gas chromatography
US3188180A (en) * 1961-05-09 1965-06-08 Huettenwerk Oberhausen Ag Process for the extraction of gases from metals
GB967047A (en) * 1962-04-27 1964-08-19 Kloeckner Werke Ag Spectrometric analysis
US3361907A (en) * 1962-12-06 1968-01-02 Nat Res Dev Apparatus for gas analysis having voltage means to accelerate electrons from an ionization chamber to a detection chamber
US3378725A (en) * 1964-04-15 1968-04-16 Beckman Instruments Inc Electron capture detector having separate ionization and sensing regions

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4367427A (en) * 1979-03-03 1983-01-04 Vacuumschmelze Gmbh Glow discharge lamp for qualitative and quantitative spectrum analysis

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Publication number Publication date
DE2105182A1 (de) 1971-11-11
FR2078263A5 (enExample) 1971-11-05

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