US2886732A - Electric discharge devices of the mercury cathode type - Google Patents
Electric discharge devices of the mercury cathode type Download PDFInfo
- Publication number
- US2886732A US2886732A US666395A US66639557A US2886732A US 2886732 A US2886732 A US 2886732A US 666395 A US666395 A US 666395A US 66639557 A US66639557 A US 66639557A US 2886732 A US2886732 A US 2886732A
- Authority
- US
- United States
- Prior art keywords
- mercury
- pool
- cathode
- electric discharge
- anchoring device
- 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 - Lifetime
Links
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 title description 27
- 229910052753 mercury Inorganic materials 0.000 title description 27
- 238000004873 anchoring Methods 0.000 description 16
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 239000007788 liquid Substances 0.000 description 6
- 230000000977 initiatory effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 3
- 238000010891 electric arc Methods 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 239000011733 molybdenum Substances 0.000 description 3
- 230000001464 adherent effect Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- 229910052580 B4C Inorganic materials 0.000 description 1
- 229910052582 BN Inorganic materials 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 101150057833 THEG gene Proteins 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- -1 for example Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000010849 ion bombardment Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J13/00—Discharge tubes with liquid-pool cathodes, e.g. metal-vapour rectifying tubes
- H01J13/02—Details
- H01J13/34—Igniting arrangements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J13/00—Discharge tubes with liquid-pool cathodes, e.g. metal-vapour rectifying tubes
- H01J13/02—Details
- H01J13/04—Main electrodes; Auxiliary anodes
- H01J13/06—Cathodes
- H01J13/14—Cooling, heating, circulating, filtering, or controlling level of the liquid
-
- 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
- H01J2893/00—Discharge tubes and lamps
- H01J2893/0072—Disassembly or repair of discharge tubes
- H01J2893/0073—Discharge tubes with liquid poolcathodes; constructional details
- H01J2893/0074—Cathodic cups; Screens; Reflectors; Filters; Windows; Protection against mercury deposition; Returning condensed electrode material to the cathodic cup; Liquid electrode level control
- H01J2893/0083—Liquid electrode level control
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2893/00—Discharge tubes and lamps
- H01J2893/0072—Disassembly or repair of discharge tubes
- H01J2893/0073—Discharge tubes with liquid poolcathodes; constructional details
- H01J2893/0074—Cathodic cups; Screens; Reflectors; Filters; Windows; Protection against mercury deposition; Returning condensed electrode material to the cathodic cup; Liquid electrode level control
- H01J2893/0087—Igniting means; Cathode spot maintaining or extinguishing means
Definitions
- the invention relates to electric discharge devicesin whichcurrent passes as an arc discharge between an anode and a pool type cathode, preferably ofumercury, .the: discharge being initiated by..theg passage of current through the cathode from a stationary ignitor electrode.
- the level of the mercury in the cathode pool into which the ignitor electrode dips may vary from time to time as a result of vaporisation of the mercury, during operation, or as the result of any tilting of the device as a whole.
- the ignition voltage required changes unless the ignitor electrode is designed to operate with varying levels and this renders sensitive operation difficult.
- the object of the invention is to provide an arrangement in which the effective level of mercury adjacent the igniter electrode is maintained substantially constant, thereby reducing variation in ignition characteristics.
- the igniter electrode is located in the vicinity of a member constituted of a material wettable by the conducting liquid of which the pool is composed, in such a manner that the initiating arc from the igniter to the cathode pool passes between the igniter electrode and conducting liquid adherent to said member, and any gap containing vaporised pool material which may exist at the region of arc initiation.
- the wettable member is hereinafter referred to as an anchoring device because of the tendency of the cathode spot associated with the are initiated through the igniter electrode to remain rooted on the surface of the anchoring device.
- the anchoring device may, and preferably does, project partially above the surface of the pool type cathode. It may be composed of an electrical conductor, for example, molybdenum, treated so as to be wetted by the conducting liquid, specifically mercury.
- the anchoring device may consist of metal sheet or wire, or of a composite structure of two or more laminae or wires, such that the conducting liquid wets the component parts and is held in the interstices between them.
- the anchoring device may consist of a porous body impregnated with the mercury, with or without any associated free mercury.
- FIG. 1 shows in cross section, an arc discharge device having a pool type cathode embodying the improvements of the invention
- Fig. 2 is a view of part of the members of Fig. 1, showing a modified construction of the igniter electrode and associated anchoring device, and
- Figs. 3 and 4 are views similar ther alternative constructions.
- the arc discharge device is seen to consist of a tubular envelope 1 of metal having flanged headers 2 and 3 inserted into the ends of the tubular portion of the envelope and arranged to support an anode 4 and a pool type cathode 5, respectively.
- the anode 4 is supported by the stem 6, insulatingly sealed to Fig. 2 showing furto the header 2 by wayJof an intermediate insulating mem- :ber 7, which .may, for :example,:be. of glass, to which are sealeda flanged member'8 connected to the anodelead 6, and:a second flanged member. 9 connected to .the 'rim .of an-aperture in the header 2.
- the inner flanged member .8 is connected to the anode lead 6 inta mannerxto make a hermetic seal thereto,: e.g. .by Welding, .andthe member 9 is similarly connected with the header 2.
- evacuatingtubulation 10 is also provided on; the header 2,which.is sealed 01$, for example, by aiglass beam-11.
- An igniter electrode 12 is supported from the header 3 in a manner to be insulated therefrom, the igniterelecitrode beingconnected by a transverse member13 with l a. terminal post 14 which. projects through the header :3, .being insulatedifrom the header andlfrom theppool 5 xby means of asurrounding glass tube 15.
- a cathode spot anchoring device 16 which consists of a solid member wettable by the mercury in the pool and located in such close proximity to the igniter electrode 12 that when an ignition potential is impressed on the igniter 12, the initiating arc passes between the igniter electrode and the cathode pool by way of mercury adhering to the anchoring device 16, and any gap containing ionised mercury which may be present there-between.
- the anchoring device may consist of a metal ring, as indicated in Fig. l, rigidly fixed to the header 3 and composed of a metal which is inherently wettable by mercury, or has been treated to cause it to be wetted by mercury, the anchoring device projecting above the level of the pool in the arrangement illustrated in Fig. 1.
- the anchoring device should consist of a metal which will withstand the heat of the are rooted thereon. It has been found that molybdenum is a suitable metal to employ for the anchoring device, the molybdenum being treated to render it wettable by mercury by being cleaned electrolytically and fired in hydrogen and then subjected to positive ion bombardment in an arc in mercury vapour.
- the header 3 is also provided with a terminal member 17 which forms the cathode connection for the device.
- the anchoring device 16 is constituted of a fiat plate 18 lying substantially parallel with the faces of the header 3 and supported by a vertical post 19, the plate 18 being located with its lower face substantially in alignment with the upper surface of the mercury level in the pool 5, the mercury spilling over the upper surface of the plate 18 which is of a material wet by mercury.
- the plate 18 may be provided with an aperture 20 into which the tip of the igniter 12 projects.
- the plate 18 instead of providing the plate 18 with an aperture as indicated in Fig. 2, it is furnished with a depression 21 into which the tip of the igniter electrode 12 projects; the plate 18 may be supported by a metal stra as indicated.
- the igniter electrode is indicated as consisting of a material of semi-conductor type, e.g. known mixtures of boron carbide, boron nitride and boron.
- a material of semi-conductor type e.g. known mixtures of boron carbide, boron nitride and boron.
- the igniter electrode may be composed of a heated member, for example, a wire 22, separately heated from a source23 through a transformer 24, as indicated in patent specification No. 2,070,501.
- an electric discharge device comprising a sealed evacuated tubular metal envelope containing a mercury pool type cathode, an anode and a fixed igniter electrode dipping into said pool type cathode between which and said cathode an initiating arc is adapted to take place,
Description
y 1959 H. DE BOYNE KNIGHT 2,886,732
ELECTRIC DISCHARGE DEVICES OF THE MERCURY CATHODE TYPE Filed June 18, 1957 .lHendy de. Boyne Knight, Rugby,
ELECTRIC DISCHARGE DEVICES OF THE 'MERCURY CATHODE TYPE England, assignor to The British Thomson-Houston Company Limited, London, England, a British company Application June 18, 1957, Serial'No. 666,395
Claims priority, application 'Great Britain June 25, 1956 1 Claim. (CL. 313164) The invention relates to electric discharge devicesin whichcurrent passes as an arc discharge between an anode and a pool type cathode, preferably ofumercury, .the: discharge being initiated by..theg passage of current through the cathode from a stationary ignitor electrode.
In devices of the character in question, the level of the mercury in the cathode pool into which the ignitor electrode dips, may vary from time to time as a result of vaporisation of the mercury, during operation, or as the result of any tilting of the device as a whole. When the level varies, the ignition voltage required changes unless the ignitor electrode is designed to operate with varying levels and this renders sensitive operation difficult.
The object of the invention is to provide an arrangement in which the effective level of mercury adjacent the igniter electrode is maintained substantially constant, thereby reducing variation in ignition characteristics.
According to the invention the igniter electrode is located in the vicinity of a member constituted of a material wettable by the conducting liquid of which the pool is composed, in such a manner that the initiating arc from the igniter to the cathode pool passes between the igniter electrode and conducting liquid adherent to said member, and any gap containing vaporised pool material which may exist at the region of arc initiation.
The wettable member is hereinafter referred to as an anchoring device because of the tendency of the cathode spot associated with the are initiated through the igniter electrode to remain rooted on the surface of the anchoring device. The anchoring device may, and preferably does, project partially above the surface of the pool type cathode. It may be composed of an electrical conductor, for example, molybdenum, treated so as to be wetted by the conducting liquid, specifically mercury. The anchoring device may consist of metal sheet or wire, or of a composite structure of two or more laminae or wires, such that the conducting liquid wets the component parts and is held in the interstices between them. Alternatively, when the pool is of mercury, the anchoring device may consist of a porous body impregnated with the mercury, with or without any associated free mercury.
The invention will now be described with reference to the accompanying drawings, in which- Fig. 1 shows in cross section, an arc discharge device having a pool type cathode embodying the improvements of the invention;
Fig. 2 is a view of part of the members of Fig. 1, showing a modified construction of the igniter electrode and associated anchoring device, and
Figs. 3 and 4 are views similar ther alternative constructions.
Referring firstly to Fig. 1, the arc discharge device is seen to consist of a tubular envelope 1 of metal having flanged headers 2 and 3 inserted into the ends of the tubular portion of the envelope and arranged to support an anode 4 and a pool type cathode 5, respectively. The anode 4 is supported by the stem 6, insulatingly sealed to Fig. 2 showing furto the header 2 by wayJof an intermediate insulating mem- :ber 7, which .may, for :example,:be. of glass, to which are sealeda flanged member'8 connected to the anodelead 6, and:a second flanged member. 9 connected to .the 'rim .of an-aperture in the header 2. The inner flanged member .8 is connected to the anode lead 6 inta mannerxto make a hermetic seal thereto,: e.g. .by Welding, .andthe member 9 is similarly connected with the header 2. An
evacuatingtubulation 10is also provided on; the header 2,which.is sealed 01$, for example, by aiglass beam-11.
An igniter electrode 12 is supported from the header 3 in a manner to be insulated therefrom, the igniterelecitrode beingconnected by a transverse member13 with l a. terminal post 14 which. projects through the header :3, .being insulatedifrom the header andlfrom theppool 5 xby means of asurrounding glass tube 15.
.The header 3 supports the cathodepool 5=which prefwerablyrconsists .of mercury, thegigm'ter, electrode 12 dipping into the pool 5 so as to make contact therewith. It will be appreciated that any change in the level of the conducting liquid in the pool 5 caused by vaporisation of the liquid in the pool during operation, or by tilting of the device, will affect the distance into which the end of the igniter electrode 12 projects into the pool. This, in turn will aifect the ignition energy necessary to ignite an arc in the device. To overcome this disadvantage there is provided a cathode spot anchoring device 16 which consists of a solid member wettable by the mercury in the pool and located in such close proximity to the igniter electrode 12 that when an ignition potential is impressed on the igniter 12, the initiating arc passes between the igniter electrode and the cathode pool by way of mercury adhering to the anchoring device 16, and any gap containing ionised mercury which may be present there-between. The anchoring device may consist of a metal ring, as indicated in Fig. l, rigidly fixed to the header 3 and composed of a metal which is inherently wettable by mercury, or has been treated to cause it to be wetted by mercury, the anchoring device projecting above the level of the pool in the arrangement illustrated in Fig. 1.
When the arc has been started between the cathode 5 and the anode 4 by reason of an ignition potential applied to the igniter 12, the arc remains rooted on the anchoring device and consequently, the anchoring device should consist of a metal which will withstand the heat of the are rooted thereon. It has been found that molybdenum is a suitable metal to employ for the anchoring device, the molybdenum being treated to render it wettable by mercury by being cleaned electrolytically and fired in hydrogen and then subjected to positive ion bombardment in an arc in mercury vapour.
The header 3 is also provided with a terminal member 17 which forms the cathode connection for the device.
In an alternative arrangement shown in Fig. 2, the anchoring device 16 is constituted of a fiat plate 18 lying substantially parallel with the faces of the header 3 and supported by a vertical post 19, the plate 18 being located with its lower face substantially in alignment with the upper surface of the mercury level in the pool 5, the mercury spilling over the upper surface of the plate 18 which is of a material wet by mercury. The plate 18 may be provided with an aperture 20 into which the tip of the igniter 12 projects.
In the arrangement shown in Fig. 3, instead of providing the plate 18 with an aperture as indicated in Fig. 2, it is furnished with a depression 21 into which the tip of the igniter electrode 12 projects; the plate 18 may be supported by a metal stra as indicated.
In the arrangement shown in Figs. 1, 2 and 3, the igniter electrode is indicated as consisting of a material of semi-conductor type, e.g. known mixtures of boron carbide, boron nitride and boron. Instead of making the igniter electrode in this manner it may be composed of a heated member, for example, a wire 22, separately heated from a source23 through a transformer 24, as indicated in patent specification No. 2,070,501.
I It will be evident that by the use of the cathode spot anchoring device adjacent which the igniter electrode is located, variations in the level of mercury in the cathode pool will have little or no elfect on the ignition characteristics of the device. Furthermore, it is well-known that since the cathode spot is anchored to the anchoring device, little or no agitation of the surface of the mercury pool will arise, as would be the case if the cathode spot were allowed to wander over the surface of the mercury pool.
What I claim is:
In an electric discharge device comprising a sealed evacuated tubular metal envelope containing a mercury pool type cathode, an anode and a fixed igniter electrode dipping into said pool type cathode between which and said cathode an initiating arc is adapted to take place,
means for preventing effective variation in the level of a said conducting liquidadjacent said'igniter electrode coim prising an annular ring of a metal capable of being wet by said mercury immersed in said cathode pool and fixed to said envelope with one rim normally projecting above said pool, said rim being located so closely in the vicinity of said igniter electrode that'fsaid initiating arc, when formed, is thereby enabled to pass from said igniter electrode to said pool by way of mercury adherent to the rim of said ring projecting above said pool and any gap containing ionized mercury which is present therebetween. 0
References Cited in the file of this patent UNITED STATES PATENTS Re. 21,861 Miles July 22, 1941 2,070,501 Westendory Feb. 9, 1937 2,154,264 Damitz Apr. 11, 1939 2,155,138 Lerns Apr. 18, 1939 2,447,646 Halpine -Aug. 24,1948 2,743,387 Lewin et al. Apr. 24, 1956 2,776,392 Colaiaco Ian. 1,1957
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2886732X | 1956-06-25 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2886732A true US2886732A (en) | 1959-05-12 |
Family
ID=10917174
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US666395A Expired - Lifetime US2886732A (en) | 1956-06-25 | 1957-06-18 | Electric discharge devices of the mercury cathode type |
Country Status (1)
Country | Link |
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US (1) | US2886732A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3254255A (en) * | 1963-01-04 | 1966-05-31 | Westinghouse Electric Corp | Mercury vapor discharge device having a novel brazing alloy |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2070501A (en) * | 1935-06-13 | 1937-02-09 | Gen Electric | Pool-type discharge device |
US2154264A (en) * | 1936-12-12 | 1939-04-11 | Siemens Ag | Vapor electric device |
US2155138A (en) * | 1936-07-28 | 1939-04-18 | Philips Nv | Mercury cathode discharge tube |
USRE21861E (en) * | 1941-07-22 | Liquid cathode device | ||
US2447646A (en) * | 1947-07-31 | 1948-08-24 | Westinghouse Electric Corp | Vapor electric device |
US2743387A (en) * | 1951-06-29 | 1956-04-24 | Westinghouse Electric Corp | Vapor electric device |
US2776392A (en) * | 1952-10-16 | 1957-01-01 | August P Colaiaco | Vapor electric device |
-
1957
- 1957-06-18 US US666395A patent/US2886732A/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USRE21861E (en) * | 1941-07-22 | Liquid cathode device | ||
US2070501A (en) * | 1935-06-13 | 1937-02-09 | Gen Electric | Pool-type discharge device |
US2155138A (en) * | 1936-07-28 | 1939-04-18 | Philips Nv | Mercury cathode discharge tube |
US2154264A (en) * | 1936-12-12 | 1939-04-11 | Siemens Ag | Vapor electric device |
US2447646A (en) * | 1947-07-31 | 1948-08-24 | Westinghouse Electric Corp | Vapor electric device |
US2743387A (en) * | 1951-06-29 | 1956-04-24 | Westinghouse Electric Corp | Vapor electric device |
US2776392A (en) * | 1952-10-16 | 1957-01-01 | August P Colaiaco | Vapor electric device |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3254255A (en) * | 1963-01-04 | 1966-05-31 | Westinghouse Electric Corp | Mercury vapor discharge device having a novel brazing alloy |
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