US2416927A - Gaseous discharge device - Google Patents

Gaseous discharge device Download PDF

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Publication number
US2416927A
US2416927A US414710A US41471041A US2416927A US 2416927 A US2416927 A US 2416927A US 414710 A US414710 A US 414710A US 41471041 A US41471041 A US 41471041A US 2416927 A US2416927 A US 2416927A
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US
United States
Prior art keywords
cathode
filament
discharge
tube
header
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
US414710A
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English (en)
Inventor
Kenneth H Kingdon
Elliott J Lawton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to BE481746D priority Critical patent/BE481746A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US414710A priority patent/US2416927A/en
Priority to GB5387/44A priority patent/GB580765A/en
Application granted granted Critical
Publication of US2416927A publication Critical patent/US2416927A/en
Priority to FR950672D priority patent/FR950672A/fr
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
    • H01J17/50—Thermionic-cathode tubes
    • H01J17/52—Thermionic-cathode tubes with one cathode and one anode
    • H01J17/54—Thermionic-cathode tubes with one cathode and one anode having one or more control electrodes
    • H01J17/56—Thermionic-cathode tubes with one cathode and one anode having one or more control electrodes for preventing and then permitting ignition, but thereafter having no control
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/50—Thermionic-cathode tubes

Definitions

  • the present invention relates to improvements in gaseous discharge devices of the controlled discharge type.
  • Y Gas filled discharge tubes have long been used as a switching means for controlling the flow of relatively large quantities of power, the control function being accomplished by the use of a grid electrode interposed between the anode and cathode of the tube.
  • the tube In the typical mode of use of such a tube the tube is maintained wholly nonconductive by the grid until the grid voltage is raised above a critical level, whereupon an arclike discharge, involving ionization of the gaseous content of the tube, is abruptly initiated.
  • control means having the general characteristics of gaseous discharge tubes but possessing a higher degree of firing accuracy and reproducibility than is commonly provided by such tubes. It is a primary object of the present invention to make available an improved form of discharge tube which possesses the required ring accuracy and uniformity and which is otherwise suited for the particular application specified' above.
  • cathodes which consist of a heated metal body coated with an Vemission venhancing substance such as an alkaline earth oxide tend to be erratic in their emissive qualities and, when used in connectionv with a control grid, lead to relatively unpredictable iiring performance.
  • Uncoated metal bodies, such as tungsten wires are much more consistent in their properties but, because of their relatively limited emission, are not inherently well adaptedr to sustain an arc-like discharge of the type which characterizes the gas-lled tube.
  • FIG. 1 shows in section a discharge device suitable embodying the invention, the device Abeing illustrated in connection with a mounting arrangement
  • Fig. 2 is an enlarged view of the cathode ofthe device of Fig. 1
  • Fig. 3 is a fragmentary enlargement of a part oi the structure .of Fig. ⁇ 2
  • Fig. 4 is a still further enlarged 'representation'of one of the elements of Fig.3
  • Fig. 5 illustrates diagrammatically a typical mode of use of the invention
  • Fig. 6 is a graphical representation useful in explaining Fig. ⁇ 5.
  • a gaseous discharge tube I0 which is indicated as being mounted axially within a hollow metal shell II; for example, the casing of an explosive projectile such'asvan anti-aircraft shell.
  • the tube IS comprises a pair of glass cylinders I3 and I4 which are separated by a metal ring I5 sealed between them land which are closed at their respective extremities by means of transverse metal headers i1 and I8. ⁇
  • the glass and metal parts referred to are. sealed together in vacuum-tight relation and to .this vend should be constituted of materialsiwhich are capable of being hermetically joined.
  • the parts I3 and I4 may consist of a borosilicate glass, and the parts I5, I1 and I8 of a metal (e. g. a nickel-iron-cobalt alloy) capable of sealing to glass of this character.
  • the upper metal header I'I which forms the anode electrode of the device, is provided centrally with a sealed-off metal tubulation adapted to be used during the fabrication of the tube for evacuating it and for introducing a suitable gaseous iilling.
  • a gas such as argon or neon at a pressure of from a few microns to a few millimeters of mercury, and in a particular case it hasV been found advantageous to use argon at a pressure of about 400 microns.
  • a terminal 2i connected to the tubulation 20 provides a means for connecting the anode part I1 to a suitable potential source (not shown in Fig. 1).
  • the intermediate ring I5 is provided with a transversely extending mesh 23 which is adapted to serve as a control grid for the tube. Control potential may be applied to the mesh through a terminal conductor 25 which is connected externally to the ring I5.
  • the header I3 in addition to serving as a closure member and base for the tube, further provides a support for a composite cathode structure having a lamentary part 21 and an auxiliary part 28 which will be described more fully at a later point.
  • the filament 21 is formed of uncoated metal and preferably of tungsten, the latter material being considered most suitable because of its ability to be maintained at a temperature of eiiective thermionic emission without excessive vaporization.
  • the filament may advantageously be on the order of 0.6 mil in diameter in order to permit it to be heated to an emitting temperature from a supply source of limited current capacity.
  • the filament is mounted between a bracket 33, which is in the form of a rectilinearly bent piece of metal secured tothe header I8, and a .relatively rigid support rod 30 which is insu latingly sealed through the header by means of a glass-to-metal seal indicated at 3I.
  • a bracket 33 which is in the form of a rectilinearly bent piece of metal secured tothe header I8, and a .relatively rigid support rod 30 which is insu latingly sealed through the header by means of a glass-to-metal seal indicated at 3I.
  • the ends of the filament wire may be preliminarily pressed between pieces of nickel foil and these pieces welded to the mounting elements as indicated at and' 36.
  • the auxiliary cathode portion 28 is shown in enlarged detail in Figs. 2 to i inclusive.
  • it comprises a folded piece of nickel 39 (Fig. 3,) which embraces a tab of aluminum foil 4I between its opposed surfaces and which is welded to the upper end of the mounting bracket 33.
  • the aluminum foil 4I which may be of the order of 2 mils in thickness, is preferably of the type known as anodized aluminum. This means that it is provided on its surface with a thin insulating lrn constituted of aluminum oxide or of a more complex aluminum compound, depending upon the circumstances of preparation of the foil.
  • OneV method of preparing or ,forming anodized aluminum comprises making the aluminum the positive electrode of an electrolytic- 4I (e. g.
  • the foil may be pricked or perforated at numerous points as indicated at 42 so that the edges of the perforations provide protruding contact points.
  • heating current is passed through the filament 21 by the application of potential between the support rod 3u and the header I 8.
  • the filament is maintained in emissive condition, although the resulting electron supply is relatively limited because of the small size of the wire.
  • no current is passed through the filament 21 by the application of potential between the support rod 3u and the header I 8.
  • auxiliary cathode part 28 in addition to the filament 2l lies in the inability of an uncoated Wire of small diameter (as is required in the instant case because of the limited heating power which can be provided in a projectile detonating unit or the like) to supply the relatively intense electron iiow required for a complete breakdown of the discharge path between the cathode structure and the anode. It is the function of the cathode part 28 to suppls7 the additional emission which is needed in this connection.
  • the cathode part'28 in order that the cathode part'28 shall not function as an electron source during the initial starting of the discharge (and thus detract from the extremely consistent firing which the uncoated iilament assures) it is preferably sum'ciently separated from the filament (i. e to the extent shown) so that it is not, maintained thermionically emissive by heat received from the lament.
  • the cathode part 28 functions exclusively as an auxiliary emitter which comes into operation only after pre-l liminary ionization' of the discharge space is produced by current flow 'from the filament. 2l. ⁇ 'Once' instant of breakdown may be said to be almost wholly governed by the emitting properties of the filament 21 and to be essentially independent of the properties of the auxiliary part 28.
  • the insulating substance applied to the auxiliary cathode part be a lm of the type produced by anodizing, although this embodiment is preferred because it assures low voltage breakdown of the discharge path.
  • the insulating substance applied to the auxiliary cathode part be a lm of the type produced by anodizing, although this embodiment is preferred because it assures low voltage breakdown of the discharge path.
  • one may employ other non-metallic insulating substances such asv nely divided aluminum oxide ⁇ (alumina), silica, or ⁇ even a material such as barium carbonate.
  • auxiliary cathode part may be diierently located than in the arrangement shown in Fig. l, although the arrangement of the latter figure is advantageous frorna ⁇ constructional viewpoint. In some cases itwill serve merely to secure the treated metal tab to the inner surface of the header I8, and it is even possible to form the auxiliary cathode merely by applying a patch of an insulating substance to the header itself.
  • Tubes of the character described herein are particularly adapted for controlling the detonating circuit of a projectile which is desired to be fired by electrical means.
  • the tube as a whole must ⁇ be capable of sustaining very great mechanical stresses such as are necessarily encountered during the firing of a projectile from a gun or cannon.
  • the force due to the initial accelei'ation of an anti-aircraft shell is from 20,000 to 30,000 times that due to gravity.
  • the envelope construction which has been described herein is found admirably adapted to sustain forces of this character without fracture.
  • the cathode header I8 is adequately reinforced by being seated against a transverse mounting block 45 which is recessed to receive the main structure of the header while providing appropriate backing for the glass-to-metal seal between the header and theglass bart I4'.
  • 'A lead washer 46 is interposed between the outwardly extending peripheral portion of the header I8 and the surface of the mounting block 45 so as to provide a deformable seat for the tube.
  • a slight spacing (e. g. a few mils) is left between the bottom of the header and the floor of the recess with- Fin which the header projects so as to allow a slight motion of the tube during high acceleration periods and to assure proper seating of the tube on the gasket 46.
  • a terminal connection for the header I8 is provided by securing to it a conductor 45.
  • the mode of use of a tube of the character specified in a projectile detonating system is in ⁇ dicated in Fig. 5 of the drawing.
  • the electrodes I1', 23', 21' and 28" are assumed to correspond to the similarly numbered parts shown in Fig. 1.
  • the cathode filament-21' has associated with it a battery 5
  • a switch 52 which may appropriately be of the centrifugal type S0 as to be closed automatically as soon as the shell is iired.
  • This condenser is in series with a detonating element 55, for example, a fuse link, which is adapted to explode the charge in the shell Whenever ⁇ the condenser 54 discharges through it.
  • a circuit which includes a condenser 51 in parallel with a resistor 58 and a xed-voltage battery 59.
  • the condenser 51 is provided with a terminal 60 which permits it 'to be charged at the time the shell leaves the gun, the amount of charge being regulated by a firing predictor which controls a voltage source to which the condenser may be instantaneously connected.
  • the condenser 51 has to be charged in a very short time (approximately ten microseconds) on account of the high muzzle velocity of the shell, so that the condenser should be as small as possible and the charging circuit sti but non-oscillatory.
  • the polarity of the battery 59 is opposed to that of the condenser "51 when charged, and the resistor 53 is of relatively high value (e. g. 109 ohms) so as to give a relatively long time constant to the condenser circuit.
  • FIG. 6 The operation of the system thus represented is illustrated graphically in Fig. 6.
  • This figure shows that the grid potential,which is represented by the irregular line A, A', A", is maintained at a voltage V1 corresponding to the voltage of the battery 59, until the instant when the shell leaves the gun.
  • the voltage V1 is favorable to a discharge between the cathode 21 and the anode I1' of the discharge tube, but such a discharge is prevented from taking place by the fact that the cathode 21 is at this time in an unheated condition.
  • the filament circuit is closed (i. e.
  • the condenser 51 is charged to a, voltage Vu which renders it negative With respect to the cathode.
  • the grid voltage immediately starts to rise again along the exponential curve A"
  • the time constant of the condenser circuit (as xed by the resistor 58) rises at y to a value which is equal to the critical firing voltage of the tube.
  • the condenser 54 is abruptly discharged through the detonatorv 55, and the shell charge is exploded.
  • a gas-filled discharge device including an anode and a cathode, said cathode including an exposed heatable lament of uncoated metal, a body of metal electrically connected to the filament but sufficiently separated therefrom to prevent thermionic emission from the body solely as a result of heat received from the filament, and an insulating substance on the surface of said body providing exposed boundaries therebetween for facilitating the initiation of eld emission from said body in the presence of ionization produced in the device by electron now from said filament.
  • a gas-filled discharge device including an anode and a cathode, said cathode comprising a heatable filament of uncoated tungsten, a body of aluminum electrically connected to the filament but suniciently separated therefrom to prevent thermionic emission from the body solely as a result of heat received from said filament, and an insulating lm on the surface of said aluminum body of the type characteristically produced by anodizing.
  • a discharge device including a gas-filled container having a metal header which closes one end of the container, an anode having a surface within the container, and a cathode, said cathode comprising an uncoated metal filament which has one terminal electrically connected to the said header and the other terminal insulated therefrom to permit heating of the lament by passage of current therethrough and a further part which is also electrically connected to the said header and which includes an exposed metal surface coated with an insulating substance adapted to facilitate initiation of held-emission from the said surface upon the occurrence of ionization of the gaseous filling of the container.
  • a discharge device including a gas-lled container having a metal header which closes one end of the container, an anode having a surface within the container, and a cathode, said cathode comprising an uncoated metal filament, a conductive member supporting one extremity of the filament from the said header, a conductor insulatingly sealed through the header and connected to the other end of the lament, a metal tab aflixed to the said supporting member in proximity to the extremity of the said filament, and an insulating substance on the surface of the said tab to facilitate initiation of field emission from the tab upon the occurrence of an ionizing discharge from the said filament.

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  • Gas-Filled Discharge Tubes (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
US414710A 1941-10-13 1941-10-13 Gaseous discharge device Expired - Lifetime US2416927A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE481746D BE481746A (es) 1941-10-13
US414710A US2416927A (en) 1941-10-13 1941-10-13 Gaseous discharge device
GB5387/44A GB580765A (en) 1941-10-13 1944-03-22 Improvements in and relating to gaseous discharge devices
FR950672D FR950672A (fr) 1941-10-13 1947-07-25 Appareil à décharge électrique dans un gaz

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US414710A US2416927A (en) 1941-10-13 1941-10-13 Gaseous discharge device

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US2416927A true US2416927A (en) 1947-03-04

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US414710A Expired - Lifetime US2416927A (en) 1941-10-13 1941-10-13 Gaseous discharge device

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BE (1) BE481746A (es)
FR (1) FR950672A (es)
GB (1) GB580765A (es)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2553569A (en) * 1949-01-07 1951-05-22 Warren H Flarity Gas tube radio-frequency switch
US2935022A (en) * 1946-03-11 1960-05-03 John E Sterner Self destruction circuit for projectile fuzes
US3295013A (en) * 1960-08-09 1966-12-27 Varian Associates Electron tubes containing gas below critical pressure
US3461334A (en) * 1967-02-27 1969-08-12 Westinghouse Electric Corp Ceramic discharge lamp

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1267827A (en) * 1914-11-06 1918-05-28 Gen Electric Electric discharge device.
US1787300A (en) * 1927-11-16 1930-12-30 Gen Electric Electric-discharge device
US1953906A (en) * 1930-12-26 1934-04-03 Electrons Inc Rectifier tube
US1959419A (en) * 1928-07-05 1934-05-22 Freedman Paul Electric arc device
US1989132A (en) * 1931-01-14 1935-01-29 Electrons Inc High voltage rectifier

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1267827A (en) * 1914-11-06 1918-05-28 Gen Electric Electric discharge device.
US1787300A (en) * 1927-11-16 1930-12-30 Gen Electric Electric-discharge device
US1959419A (en) * 1928-07-05 1934-05-22 Freedman Paul Electric arc device
US1953906A (en) * 1930-12-26 1934-04-03 Electrons Inc Rectifier tube
US1989132A (en) * 1931-01-14 1935-01-29 Electrons Inc High voltage rectifier

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2935022A (en) * 1946-03-11 1960-05-03 John E Sterner Self destruction circuit for projectile fuzes
US2553569A (en) * 1949-01-07 1951-05-22 Warren H Flarity Gas tube radio-frequency switch
US3295013A (en) * 1960-08-09 1966-12-27 Varian Associates Electron tubes containing gas below critical pressure
US3461334A (en) * 1967-02-27 1969-08-12 Westinghouse Electric Corp Ceramic discharge lamp

Also Published As

Publication number Publication date
FR950672A (fr) 1949-10-04
BE481746A (es)
GB580765A (en) 1946-09-19

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