US2600246A - Caesium electric discharge device - Google Patents

Caesium electric discharge device Download PDF

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Publication number
US2600246A
US2600246A US221856A US22185651A US2600246A US 2600246 A US2600246 A US 2600246A US 221856 A US221856 A US 221856A US 22185651 A US22185651 A US 22185651A US 2600246 A US2600246 A US 2600246A
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US
United States
Prior art keywords
caesium
envelope
insulator
cathode
anode
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
Application number
US221856A
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English (en)
Inventor
Albert W Hull
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General Electric Co
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General Electric Co
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Filing date
Publication date
Priority to BE510755D priority Critical patent/BE510755A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US221856A priority patent/US2600246A/en
Priority to FR1059952D priority patent/FR1059952A/fr
Priority to DEI5750A priority patent/DE940180C/de
Priority to GB9961/52A priority patent/GB708325A/en
Application granted granted Critical
Publication of US2600246A publication Critical patent/US2600246A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01J17/04—Electrodes; Screens
    • H01J17/12—Control electrodes

Definitions

  • My invention relates to electric discharge devices of the type generally known as thyratrons which utilize an ionizable medium and a control grid, and, more particularly, to such devices employing caesium, rubidium or alloys thereof, as the ionizable medium.
  • caesium vapor electric discharge device has long been a goal of the discharge device art, since it is known that caesium vapor possesses the lowest ionization potential, i. e., 3.9 volts, available and, therefore, that a caesium vapor device operates at a low arc drop resulting in very high efficiencies. Further, it has been found that in a caesium vapor device having a small reservoir of liquid caesium, no oxide coating or other special electron emitting surface must be applied to the cathode, since a monatomic layer of caesium is .condensed from the caesium vapor upon the hot cathode and serves as an efficient source of emitted electrons.
  • the emitting surface made up of a monatomic layer of condensed caesium has a very long life and high current capacity, since the monatomic layer of caesium is maintained on the cathode, even under severe operating conditions, by an equilibrium process of condensation on and evaporation of caesium from the cathode surface.
  • a successful caesium vapor electric discharge device possesses the desirable characteristics of high efficiency, long life, high current capacity, small size, and ruggedness.
  • caesium is a chemically active element which attacks many materials, particularly glass insulators, employed in making a hermetically sealed envelope and insulating various electrodes from one another.
  • caesium resistant ceramic instead of glass, insulators and caesium resistant seals are used.
  • caesium re-' sistant ceramics while excellent insulators in air and at room temperature, behave quite differently in the presence of caesium vapor at elevated temperatures.
  • I provide an electric discharge device having a cylindrical shell, with suitable end closures, forming the greater part of ahermetically sealed envelope and serving also as an second ceramic insulator bonded between the. control grid structure and the. anode. shell and,
  • control grid is made up of tubular members. sup.- ported between headers to define a path for cooling fluid through the control grid. amount of caesium is present in the sealed envelope, lying; in. liquid form. in a small trough near the botton'iv end of..the.- anode. shell, or in some. other portion so located with respect to the circulation path of the: cooling fluid that its temperature is lower than that of any other part of the enclosure.
  • the tube In operation, the tubeis heated, sufileiently, by cathode heating means or external means, so that aportion of the caesium vaporizes to the proper; vapor pressure.
  • the liquid caesium. is thus kept cooler than any part in the tube, sincethe fiuid passes nearit first".
  • The; first insulator is; kept warmer than the liquid caesium, even. though the: fluid passes linearly in the flow cycle, since iii is. positioned to. receive.- radiated heat from thelheated cathode stem.
  • the cooling. fluid cools the. anode and absorbs heatfrom. the, anode so that by the time the.
  • Fig. l is an elevational view: in'section of an electric discharge device illustrating one embodimentof: my invention; and Fig. 2 is a crosssectional view takenalong the line.2--2 of Fig; 1.
  • FIG. 1 Referring now to Figs- 1 and 2,. I have. shown an electric discharge. device comprising a her- A. small.
  • metically sealed envelope including a cylindrical shell I, the inner surface of which serves, in this preferred form, as the anode of the device.
  • an annular header 2 is provided through which a cathode metal support cylinder 3 extends.
  • a cylindrical insulator 4 made of a material not attacked. by caesium, such as ceramics of the alumina or of the magnesium silicate groups. As shnwn.
  • a metal collar '5 is bonded at one end thereof to support cylinder 3 and at the other end thereof to a metal connecting sleeve 6 which-,in. turn, is joined to insulator
  • a preferable method of efiecting a reliable seal between metal sleeve 6 and ceramic insulator 6 is one such as the titanium hydride method disclosed. and. claimed: in the copending application of. Bondley, Serial No. 36,244, filed January 30, 1948, and. assigned. to they same assignee as. that of the presentapplication.
  • a second metalconnectingsleeve '1- is. bonded,. in a, manner-similar to that for sleeve 6, to. the. outer surface of insulator 4, well spaced from the; inner.- end of insulator 4, and welded. to the. header 2, asshown, to complete the lower; portion of the sealed envelope.
  • The. cathode structure includes a. plurality of vanes 8: which extend; radially. from. cylinder 3 and. which may be covered: with screen. mesh. .9 to. increase. the. effective areazand; emission ca.- pacity of. the. cathode.
  • Cylinder 3; vanesfi, and mesh 9- are. preferably? made oii'clean nickel, no special emitting: surface: being required. in. this caesium. vapor device. as explained hereinbeiore.
  • A. heat conservingshieldlil is supported. from cylinder 3 to.surround vanes. 8, beingas showrra generally closed. cylindrical metallic covering having a' plurality of; layers? H.” of thin.
  • metal or metal foil: and: provided with openings 12: in the side: walls through which electrical. discharge may take; place between the.:anode;and; the' oathode;
  • the interior.” ofsupport cylinder: 3. serves as an. hermetically sealed. chamber containing a heating element [3,. preferably" tungsten.
  • Heat'- ing element i3 is wound upon a ceramic-sleeve i l which-surrounds the. inner end; ofia metallic support and electrical leadi-inv member [5,. to. which one end of element I3 is welded.
  • the other: end of. element. i3; is. welded to astud 16 extending inwardly-from a cap. or closure.
  • member [T which closes the innermost; end of the chamber.
  • Support and lead-in member [5 extendsthrough. an insulating; seal to the; exterior of; the chamber, such a seal. being formed by a connectingcylinder I8 Weldedat one end therof: to: the innerisurface. of cylinder 3 and sealed; at: the outer end to a; glass cylinder (.9. A closing: collar 20' is sealed to cylinder I9 and, in turn, welded. to member l5.
  • Member ['51 maybe spaced: from cylinder 3 by a heataresistant' insulation.
  • ring 21 as'shown, if it2istnecessary or: desirable. Heating current is supplied to member I5 anda. ter.:-- minal 22 which, being attached to cylinder 3, serves as the cathode terminal;
  • header Zthere Onthe inner surface of header Zthere is located: a. stiffening'ring 23' having an inwardly'exitending flangeld'. Ring Zdserves to strengthen the relatively-thin header 2' in supporting the cathode structure, while flange 24 provides an annular reservoir between itself and shell I to hold a small amount of liquid metal 25, which may be caesium, rubidium, or certain alloys thereof giving an ionizable medium having the desired features of caesium described herein before. v
  • shell I The upper end of shell I is closed by a second annular header 26, also having a stiffening ring 2'1, through which a metal support cylinder 28 extends to support the control grid structure.
  • the sealed envelope is completed by a collar 23 bonded at one end thereof to cylinder 28 and at the other end thereof to a metal connecting sleeve 30.
  • Sleeve 30, in turn, is sealed to a cylindrical insulator 3
  • another metal connecting sleeve 32 is also sealed to insulator 3
  • a unique structure preferably made of iron, is supported from cylinder 28, and comprising a pair of ducts 33 and 34 welded into cylinder 28 and communicating with a ring header 35 into which the upper ends of a plurality of grid-forming tubes 36 are fastened.
  • Supported within cylinder 28 by an annular disk 31 is a tube 38, the inner end of which communicates with the interior of the sealed envelope and on the upper end of which there is provided a seal-01f tubulation 39 for reducing the pressure in the envelope and making the final seal.
  • Annular disk 31 also closes the lower end of the annular space between cylinder 28 and tube 38 which is a part of the cooling fluid flow path, as will be explained hereinafter. As shown more clearly by Fig.
  • the annular space between cylinder 28 and tube 35 is divided by a diametral partition ll] and ring header 35 is divided by a similar diametral partition 4
  • end of cylinder 28 is a fitting 53 to conduct the flow of cooling fluid, as will be explained hereinafter, and around fitting 43 a control grid terminal 44 may be conveniently located.
  • a small opening 35 is made through cylinder 26, as shown.
  • the jacket is completed by sleeves 52 and 53, bonded to bellows 56 and 5!, and sealed into glass insulators 54 and 55; and by other sleeves 56 and 51 sealed into insulators 56 and 55 and bonded to collars 53 and 59, which, in turn, are bonded to cylinders 3 and 23.
  • An entrance 6!] to the cooling jacket is formed on sleeve 56, the ultimate exit being formed by fitting 43.
  • Attached to the upper and 62 are mounted respectively on sleeves I and 32; and similarly spiral fluid flow paths past headers 2 and 26 are defined by bafiies 63 and 64, mounted on closure members 48 and 49.
  • the device Since the device is intended to operate with the coolest portion of the tube, i. e., the caesium reservoir defined by flange 24, at around C. so that the caesium vapor pressure is approximately 10 microns, it is preferable to provide an external sheathed heating element 65 around cylinder 46 to bring the device up to temperature before commencing operation and to hold it there during standby periods.
  • the cathode heating element I 3 may be used for this purpose, but its action is slower and, therefore, less con venient.
  • cooling fluid to be used must be one which is electri cally non-conductive and which is unaffected by the relatively high temperatures involved.
  • Water of course, is not satisfactory but certain oils such as the silicone oils have been employed with success as cooling fluids for the device illustrated.
  • cooling fluid circulated in the following path: Relatively cool fluid enters the device through entrance 66, passes insulator 4, goes through baffles EI and 63, and thence through an opening 61 in shell I and into the space between shell I and cylinder 46.
  • the liquid caesium 25 held by shell I, header 2, and flange 24 lies near the early part of the cooling fluid flow cycle and is, therefore, maintained as the coolest part of the device.
  • insulator G is surrounded by cooling fluid in an earlier part of the flow cycle, its inner surface is maintained at a temperature from 10 C. to 50 C. above the temperature of the liquid caesium by heat radiated directly from cylinder 3 which is relatively hot due to heat re ceived from element I 3.
  • the cooling fluid After entering the space between shell I and cylinder 46, the cooling fluid flows in the spiral path around shell I, cooling the anode and being warmed as a result.
  • the fluid next flows through a second opening 68 in shell I, past header 26 in a spiral path defined by baffle 64 and upwardly past insulator 3I in a spiral path defined by bafile 62.
  • the fluid after passing anode shell I, is warmer than when it passed liquid caesium 25 and, therefore, insulator 4
  • the inner surfaces i. e.,
  • ihe ioni-zable medium employedin the. device of? my invention. be; caesium or; rubidium. however, I, have. discovered, that: an, alloy of ca-csiumionrubidium .with'somej other: alkali metal such": as potassium. or. sodium. may be used, to further advantage, and; therefore, I prefer in some, cases to" use a caesium-sodium alloy, for example. for the ionizable medium.
  • first ceramic insulator formingpart of the envelope Wall'and positioned to receive heat from saidcathode-structure during the operation of said device;- a control grid structure; means supporting said control grid structurewithin said envelope in insulated relation with respect there-- toincluding a second ceramic insulator forming part of the envelope-Wall; and means definingcooling paths'in heat exchange relation with said portion of said envelope, one electrode of said device, and said second insulator in series so that during operation of said device-cooling fluid may be circulated through said paths in the order named to maintain said.
  • second insulator at a temperature above the temperature of said liquid metal.
  • An electric discharge device of the thyratrontype comprising an hermetically sealed envelope; a quantity of liquid metal selected from the g'roup consisting of caesium, rubidium, alkali metal alloys of' caesium, and alkali metal alloys of rubidium Within said envelope; a cathode structure; means supporting said cathode structure within said'envelope in insulated relation'thereto including a first ceramic insulator forming part of the envelope wall; a control grid structure ineluding a pair of headers and a plurality of tubular members connected between said headers defining a cooling path therethrough; means supporting said control grid structure within said envelope in insulated relation with respect thereto including a second ceramic insulator," said first ceramic insulator being positioned to receive heat from said cathode structure; and means defining a cooling fluid flow patharound said, second insulatorin series with said control grid cooling path.
  • a grid controlled electric discharge device comprising: an hermetically sealed envelope in cluding a metal portion forming an anode for said device; a quantity of liquid metal selected from the-group consisting of caesium, rubidium, alkali metal alloys of caesium, and alkali metal alloys ofrubidiumwithin said envclopera cathode structure; means supporting said cathode structure within said envelope in insulated relation with respect thereto including a: first ceramic insulator forming part of the envelope Wall and positioned to receive heat from said cathode structure durmg operation of said device; a control grid structure; means supporting said control grid structurewithin said envelope in spaced relation between said cathode structure andsaid envelopeand in insulated relation with respect to said envelope including a second ceramic insulator form ing part of the envelope wall; means defining cooling paths in heat exchange relation with the region containing said liquid metal, said anode portion of said envelope, said second insulator, and said control grid structure so that during operation of said device
  • An electric discharge device of the thyratron type comprising an hermetically sealed metal envelope forming an anode for said device, a reservoir defined in one end of said envelope, a quantity of liquid caesium in said reservoir, a cathode structure, a first ceramic insulator supporting said cathode structure from said one end of said envelope and positioned to receive heat from said cathode structure during operation of said device, a control grid structure including a plurality of tubular members supported in spaced relation between headers defining a cooling path therethrough, a second ceramic insulator supporting said control grid structure from the opposite end of said envelope, and jacket means around said envelope and said second insulator defining cooling paths in heat exchange relation therewith,
  • said jacket means and control grid structure being arranged so that cooling fluid may be circu- 'lated past said envelope and said second from said one end of said envelope and positioned to receive heat from said cathode structure during the operation of said device, a control grid structure, a second ceramic insulator supporting said control grid structure from the opposite end of said envelope, and jacket means definin a cooling path around said anode and said second insulator in the order named so that during the operation of said device cooling fluid may be circulated through said jacket means to maintain said liquid caesium at a first predetermined temperature, to maintain said anode below a second predetermined temperature but above said first predetermined temperature, and to maintain said second insulator above said first predetermined temperature.

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US221856A 1951-04-19 1951-04-19 Caesium electric discharge device Expired - Lifetime US2600246A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE510755D BE510755A (enrdf_load_stackoverflow) 1951-04-19
US221856A US2600246A (en) 1951-04-19 1951-04-19 Caesium electric discharge device
FR1059952D FR1059952A (fr) 1951-04-19 1952-04-16 Tube à vapeur de césium
DEI5750A DE940180C (de) 1951-04-19 1952-04-19 Gittergesteuerte elektrische Metalldampf-Entladungsroehre mit einer gewissen Menge von mit der Kolbenwand in Beruehrung befindlichem fluessigem Caesium, Rubidium oder von deren Alkalimetallegierungen zur Bildung des Metalldampfes
GB9961/52A GB708325A (en) 1951-04-19 1952-04-21 Improvements in and relating to electric discharge devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US221856A US2600246A (en) 1951-04-19 1951-04-19 Caesium electric discharge device

Publications (1)

Publication Number Publication Date
US2600246A true US2600246A (en) 1952-06-10

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Application Number Title Priority Date Filing Date
US221856A Expired - Lifetime US2600246A (en) 1951-04-19 1951-04-19 Caesium electric discharge device

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US (1) US2600246A (enrdf_load_stackoverflow)
BE (1) BE510755A (enrdf_load_stackoverflow)
DE (1) DE940180C (enrdf_load_stackoverflow)
FR (1) FR1059952A (enrdf_load_stackoverflow)
GB (1) GB708325A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE941558C (de) * 1953-03-20 1956-04-12 Walter Daellenbach Dr Ing Elektrisches Entladungsgefaess
DE941627C (de) * 1952-12-20 1956-04-12 Fkg Ag Caesium-Adsorptionskathode mit Wolframunterlage und Verfahren zu deren Herstellung
DE962281C (de) * 1953-03-06 1957-04-18 Walter Daellenbach Dr Ing Caesiumdampf-Entladungsgefaess mit einer Gluehkathode und einer diese topffoermig umschliessenden Anode, deren Aussenseite gekuehlt wird
DE1020739B (de) * 1954-05-15 1957-12-12 Iapatelholdia Patentverwertung Steuerbares Entladungsgefaess mit einer Fuellung aus Alkali-Metalldaempfen

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB230026A (en) * 1924-03-01 1925-12-31 American Appliance Company Improvements in gaseous electric space current device
DE642256C (de) * 1932-07-02 1937-02-26 Aeg Anordnung zur Vermeidung des Durchzuendens von gittergesteuerten Gas- oder Dampfentladungsstrecken, die in Relais- oder Messeinrichtungen arbeiten, beim Anschalten der Einrichtung an die Anodenspeisegleichspannung
US2513920A (en) * 1947-08-14 1950-07-04 Gen Electric Fluid-cooled electric discharge device
US2489891A (en) * 1948-12-27 1949-11-29 Gen Electric Cesium electric discharge device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE941627C (de) * 1952-12-20 1956-04-12 Fkg Ag Caesium-Adsorptionskathode mit Wolframunterlage und Verfahren zu deren Herstellung
DE962281C (de) * 1953-03-06 1957-04-18 Walter Daellenbach Dr Ing Caesiumdampf-Entladungsgefaess mit einer Gluehkathode und einer diese topffoermig umschliessenden Anode, deren Aussenseite gekuehlt wird
DE941558C (de) * 1953-03-20 1956-04-12 Walter Daellenbach Dr Ing Elektrisches Entladungsgefaess
DE1020739B (de) * 1954-05-15 1957-12-12 Iapatelholdia Patentverwertung Steuerbares Entladungsgefaess mit einer Fuellung aus Alkali-Metalldaempfen

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Publication number Publication date
FR1059952A (fr) 1954-03-30
GB708325A (en) 1954-05-05
DE940180C (de) 1956-03-15
BE510755A (enrdf_load_stackoverflow)

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