US3818259A - Gas-filled discharge tube for transient protection purposes - Google Patents

Gas-filled discharge tube for transient protection purposes Download PDF

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Publication number
US3818259A
US3818259A US00335013A US33501373A US3818259A US 3818259 A US3818259 A US 3818259A US 00335013 A US00335013 A US 00335013A US 33501373 A US33501373 A US 33501373A US 3818259 A US3818259 A US 3818259A
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United States
Prior art keywords
electrodes
discharge
housing
gap
gas
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Expired - Lifetime
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US00335013A
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English (en)
Inventor
Jensen C Schleimann
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Telefonaktiebolaget LM Ericsson AB
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Telefonaktiebolaget LM Ericsson AB
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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
    • 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

Definitions

  • a gas-filled discharge tube for use as transient protection device has at least two electrodes separated by a [30] Forelgn Apphcauon Pnonty Data discharge gap and one insulating body which provides Mar. 13, i972 Sweden 3142/72 a vacuum Sealed housing for the eiectrodes Between the electrodes the insulating body defines a narrow [52] US. Cl. 313/217, 317/62 gap in the dii-ectioi-l f the discharge gap to the [51] Int. Cl.
  • the tubes mostly consist of a several; electrodes which are electrically insulated from each other by a suitable mutual distance and are placed in a vacuum tight housing containing a gas of suitable kind and with suitable pressure.
  • the tubes can, for example, be connected between ground and a line point where transients can occur, or they can be connected between other points, which may be subjected to overvoltage transients.
  • three-electrode tubes are preferred. A central electrode is then generally connected to ground while the other two electrodes are connected to points which are to be protected.
  • the electrode material, the distance between the electrodes and the type and pressure of the gas are important factors for determining the striking orfiring voltage of the discharge tube.
  • the striking voltage ought to be somewhat higher than the voltage which normally exists between the protection points so that if, in consequence of a transient, the voltage exceeds a value which involves a risk for the equipment, the tube shall ignite.
  • the discharge at first takes place as a glow discharge and the voltage through the tube and thus through the protected equipment is limited to the glow voltage of the discharge tube.
  • the current through the discharge tube can be so large that the glow current is transformed into an arc discharge. This often occurs for currents of about the value 0.5 ampere.
  • the voltage through the tube and the equipment then decreases to avalue which is considerably lower than the glow voltage.
  • the arc voltage can lie at such low values as about volts or at somewhat higher values, however, in general with a maximum of about 45 volts.
  • the arc discharge is transformed back into a glow discharge and ceases, when the voltage of the transient is no longer sufficient to keep the glow current of the discharge tube alive.
  • the extinction voltage can differ from the striking voltage, but it should be higher'than the voltage which normally exists between the protection points so that the tube will be extinguished when the transient ceases.
  • the tubes have been provided with screens which are to reduce the possibility that sputtering material can reach the insulating part of the tube, or the dimensions of the tube have been increased for example to be able to use housings with a longer insulation section or to have the possibility of placing the electrode gap'at one end of the tube and the insulation part at the other end.
  • the insulation difficulties have been overcome without introducing extra elements or other more expensive measures. Simultaneously improvements in the striking voltage characteristics have been attained.
  • FIG. 1 shows a now common embodiment for a transient protection device
  • FIG. 2a to 2c illustrate an examples of insulatorelectrode-gaps according to the invention
  • FIG. 3 gives an example of a two-electrode tube according to the invention
  • FIG. 4 shows different types of electrodes to be used A in discharge tubes according to the invention.
  • FIG. 5 shows the application of the invention to a three-electrode tube.
  • FIG. 1 showing an earlier known protection device the electrodes E, and E; are vacuum tightly joined with the insulator body K.
  • the joining process can take place by vitrification or by means of a suitable soldering process. In both cases the process often takes place in an atmosphere of the intended filling gas. Sometimes soldering and pumping and gas-filling take place as two operations.
  • the arrangement has then generally been provided with a pump pipe, for example, in the one electrode, whereby the tube can be evacuated and gas filled after the soldering.
  • the pump pipe is sealed after the gas dosage.
  • the electrodes have been provided with electron emission promoting material A and A in the gap surfaces, but in recent years pure metal-electrodes seem to gaining ground because they have a quicker striking process and thereby a better protection effect than what is usual, if activated electrodes are used.
  • the discharge causes as mentioned above material sputtering whether pure or activated electrodes are used. This will be most dominant in the arc region of the discharge.
  • the are discharge also causes a highly increased gas pressure in the discharge itself and in its immediate vicinity. The pressure is often of such a magnitude that it may become explosive.
  • the letter X indicates an arc discharge, which has been caused by a transient. As long as the arc discharge exists, the electrical and magnetic forces existing in the discharge can, to a certain extent, keep the are material together so that this preferably moves in the longitudinal direction of the arc discharge.
  • the are discharge causes then, in the first place, a material transport between the electrodes, but when the arc discharge ceases, the material assembling effect of the discharge also ceases and the result will be that with great power sputtered or vaporized material will be thrown out of the gap and towards the insulator K and the electrode sides as is indicated by the arrows.
  • a certain condensation of electrode material on the part of the insulatorK, which is situated immediately outside the gap, can be favourable when pure metal electrodes are used, as this condensation material byits field emission characteristics can contribute to'a very quick priming mechanism, but the part of the sputtering material, which is thrown up between the electrode sides and the insulator and which is condensed there, quite soon results, in limiting the useful life of the tube.
  • the gap between the electrode sides and the insulator is so narrow that only a small quantity'of the sputtering material can be thrown into the such gap and the throwing,which possibly takes place, causes a. local counter pressure and thereby prevents or considerably reduces the depth of the throwing in the gap range.
  • a gap according to the invention can of course be varied in many ways byadaptation'between insulator and electrode form.
  • the gap'can have an equidistant width, FIG. 2a, or it can be gradually reduced towards the electrode-insulator-junction.
  • the latter embodiment means a possibility to center slightly cone-shaped electrodes correctly in a cylindric insulator body, see FIG. 2b.
  • the passage between electrode side and electrode gap surface can be varied in many ways without departing from the idea of the invention.
  • FIG. 2c-e give such examples, where FIG. 20 shows a rounded form, FIG. 2d shows a diagonal cut-off corner part while FIG. 2e shows a stepv formed passage.
  • a further advantage can be obtained considering the insulation qualities and the loading capacity, if the narrow gaps between the electrodes and the insulating body are combined with cavigaps S, and S, according to the invention.
  • the cavities'H and H have been formed. Because of the relatively large volume, which the cavities H and H, cause, the sputtering products from an arc discharge have, for example, at X a tendency to be thrown into the region of the cavity, wherethe counter pressure will be relatively low.
  • the gap according to the invention is used together with plane electrodes.
  • the letter reference charge 1 indicates the length of the gap.
  • the gap has a length of 1 mm and a maximum width of 0.10
  • FIG. 4 shows some examples of possible forms of cavities, FIG. 4a showing a step formed cavity, FIG. 4b an arcuate cavity and FIG. 40 a cylindric cavity.
  • the gap surfaces of the electrodes plane or formed with cavities can be activated by electron emission promoting material or they can be pure metal surfaces, or possibly a combination of both.
  • the surfaces can be even, roughen or in another way uneven.
  • FIG. 5 finally, is shown an example of a threeelectrode tube according to the invention.
  • the outer electrodes 'E and E are shown as cavity electrodes, compare FIG. 3, while the central electrode E is open so that all three electrodes are in a chamber in common.
  • the gaps between all three electrodes and the two insulator bodies K, and K are made according to the invention. Because of drawing technical reasons the tubes have been shown in a greatly enlarged scale. As an example of a size of a tube, it can be mentioned that a tube formed as is shown in FIG. 3 can have a diameter of 5 mm and a length of 6 mm.
  • a gas-filled discharge device for transient protection comprising, at least two symmetrical electrodes having face surfaces, an insulation housing mechanically connected to said electrodes for supporting said electrodes in a vacuum-tight housing such that the face surfaces of. said electrodes are opposite each other across a discharge gap in plane perpendicular. to the I symmetry axis of the electrodes, said housing and said electrodes being so dimensioned that an annular gap exists between each said electrode and said housing in the region of their mechanical connection, said annular gap having a length of at least 1 mm and a thickness of less than 0.15 mm, and an ionizable gas within said housing.
  • a gas-filled discharge device for transitent protection comprising, at least two symmetrical electrodes having face surfaces, an insulation housing mechanically connected to said electrodes for supporting said electrodes in a vacuum-tight housing such that the face surfaces of said electrodes are opposite each other across a discharge gap in plane perpendicular to the symmetry axis of the electrodes, said housing and said electrodes being so dimensioned that an annular gap exists between each said electrode and said housing in the region of their mechanical connection, said annular 6.
  • said cavgap having a length of at least 1 mm and a thickness of ity is partially spherical in shape.
  • the discharge device of claim 4 wherein said cavsaid electrodes being provided with a cavity, and an ity is generally conical in shape.
  • ity is cylindrical in shape.

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  • Gas-Filled Discharge Tubes (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
US00335013A 1972-03-13 1973-02-23 Gas-filled discharge tube for transient protection purposes Expired - Lifetime US3818259A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE03142/72A SE365066B (ja) 1972-03-13 1972-03-13

Publications (1)

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US3818259A true US3818259A (en) 1974-06-18

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US00335013A Expired - Lifetime US3818259A (en) 1972-03-13 1973-02-23 Gas-filled discharge tube for transient protection purposes

Country Status (5)

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US (1) US3818259A (ja)
CH (1) CH560982A5 (ja)
DE (1) DE2310960B2 (ja)
GB (1) GB1418982A (ja)
SE (1) SE365066B (ja)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3989985A (en) * 1973-09-13 1976-11-02 Siemens Aktiengesellschaft Surge voltage arrester
US4015172A (en) * 1975-03-17 1977-03-29 Siemens Aktiengesellschaft Two path voltage arrester
FR2388427A1 (fr) * 1977-04-18 1978-11-17 Reliable Electric Co Dispositif eclateur pour dissiper les surtensions
US4493004A (en) * 1982-03-03 1985-01-08 Siemens Aktiengesellschaft Surge arrester with a gas-filled housing
US6708638B2 (en) 2001-06-18 2004-03-23 University Of Florida Research Foundation, Inc. Method and apparatus for lightning protection
CN103311073A (zh) * 2013-05-17 2013-09-18 东莞市华炜雷电防护设备有限公司 一种多间隙放电管模块及其封装结构
US10770867B2 (en) 2017-07-05 2020-09-08 Tdk Electronics Ag Arrester

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3454811A (en) * 1967-04-18 1969-07-08 Bell Telephone Labor Inc Gas tube surge (overload) protection device
US3702952A (en) * 1971-10-12 1972-11-14 Western Electric Co Gas tube surge protective device and method for making the device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3454811A (en) * 1967-04-18 1969-07-08 Bell Telephone Labor Inc Gas tube surge (overload) protection device
US3702952A (en) * 1971-10-12 1972-11-14 Western Electric Co Gas tube surge protective device and method for making the device

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3989985A (en) * 1973-09-13 1976-11-02 Siemens Aktiengesellschaft Surge voltage arrester
US4015172A (en) * 1975-03-17 1977-03-29 Siemens Aktiengesellschaft Two path voltage arrester
FR2388427A1 (fr) * 1977-04-18 1978-11-17 Reliable Electric Co Dispositif eclateur pour dissiper les surtensions
US4128855A (en) * 1977-04-18 1978-12-05 Reliable Electric Company Surge arrester
US4493004A (en) * 1982-03-03 1985-01-08 Siemens Aktiengesellschaft Surge arrester with a gas-filled housing
US6708638B2 (en) 2001-06-18 2004-03-23 University Of Florida Research Foundation, Inc. Method and apparatus for lightning protection
CN103311073A (zh) * 2013-05-17 2013-09-18 东莞市华炜雷电防护设备有限公司 一种多间隙放电管模块及其封装结构
CN103311073B (zh) * 2013-05-17 2015-09-02 东莞市华炜雷电防护设备有限公司 一种多间隙放电管模块及其封装结构
US10770867B2 (en) 2017-07-05 2020-09-08 Tdk Electronics Ag Arrester

Also Published As

Publication number Publication date
CH560982A5 (ja) 1975-04-15
SE365066B (ja) 1974-03-11
DE2310960B2 (de) 1979-10-25
DE2310960A1 (de) 1973-09-20
GB1418982A (en) 1975-12-24

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