US2515361A - Electric discharge device - Google Patents

Description

July 18, 1950 R. VANCE ELECTRIC DISCHARGE DEVICE Filed Dec. 15, 1946 FIG. I

lNl ENTOR R. L. VANCE Br ATTORNEY Patented July 18, 1950 UNITED PATENT or-r1 cc :ELEGTRIC DISCHARGE DEVICE Robert L. Varitza'WeStfield, N. 3., assignor to Bell Telephone Laboratories, Incorporated, New

York, N.Y., a-corporation of New York xApplication December 13, 1946, Scrial'No; 715,934

4 Claims. (o1. zap-271.5)

, Thisoinvention.itlatesto electric discharge devicesrand more particularly to gaseous discharge devices of the trigger control type.

Trigger controltype gaseous discharge devices comprise, basically, a cathode, a work or output anode and, a control electrode or anode, in an between the cathode and control anode be initiated is critically dependent upon the length of'the control :gap. It is eminently desirable,

therefore, crder-ilthat such devices may meet.

prescribed operating -& requirements accurately,

that the controle gap be-of exact specified length H and that thi'slengthbe maintained even despite rough physical handlingor-use of the device.

Qne objectof this: invention is :to facilitate the realization and. maintenancelof an exact prescribed control: gap,- lengthin gaseous discharge 1 devices of-the trigger control type.

Another object or" thi invention is to attain such "ccntrol-gap-ain a simple, readily fabricable and rugged construction.

A further object or this invention is to obtain uniform heating .cf. a. relatively... large area cold cathode of an electronic discharge .device during the processing of thedevice.

In .accor'clancewithpne feature of this inven.

tion, the cathode and control anode of an 'elec-' t'ric .d-i'schar'geudevicelare supported from acstem and ares'so" constructed and iarranged that "when they are assembled with the stem, thespa'cing between athese electrodes isr"autmatically 1i2and accurately fixed, whereby aa-control gap exactly meetingwpreassignede 'lengthvsrequire'ments' is realized.

In accordance withanothe'r feature of; this ,inventiongthe cathbdezis constructed of twoor'more arcuate sheet members having transverse edge flanges, juxtaposed flanges on adjacent members being joined together, and the several flanges being provided with integral mounting lugs. The cathode thus constitutes a rugged unit and, because of the flanges, uniform heating of the 2 cathode is realized during the processing of, the device. I

The invention and the abovenoted. and other features thereof will beunderstood more clearly and fully from the following detailed description with reference to the accompanying drawinginwhich: I

Fig. 1 isan ,elevational view in, perspective of a trigger control type. of gaseous discharge device illustrative of. one embodiment of this invention, a portion of the enclosing vessel being broken away to show the internal structure; and

Fig. 2 is a cross-sectiona1 view of the device taken along plane 2-2 of Fig. l. n

Referring now to the drawing, the electric discharge device therein illustrated comprises a vitreous enclosing vessel ll) having anionizable atmosphere, for example spectroscopically pure argon at a -cold,pressure,oflll. 5 millimeters of mercury, therein.,. Joined to the vessel It! is an insulating base I I carrying terminals 12 to which the electrodes of theldevice are connected, The enclosing vessel ID has therein astem l3 which terminates at its inner end in a .press'having a generally triangular or bi-winged portion I4 and an arm l5 extending from the apical part of the portionlfi and having its medial plane coincident WiththatOfthe portionlll. v

Apair-of rigid parallel rods or wires "5, equally spaced from the medianplane noted and aligned normal thereto, are embedded in the press por- .of the lead in systemuforr-the cathode, IT. .The

cathode, which, i'soarcuatelin transverse section as shown;lin. Fig. 2,,1advantageouslyis formed of sheet metaL foriex'ample-nickel, and is constructedoftwo onmore sections. Each section is provided with integral flanges. it at opposite ends, and the :adjacent flan ges are secured together, as by welding. The ends of each of theflanges are bent to formfmounting lugs l 9, which are afiixed, as; by welding-, to the rods; or WiresJB. Because of the 'lugswl 9, -.-when the cathode is mounted on the wires orerods-lfi it is v fixed in a predetermined position with respect to the rods or wires 16 .and issecurely anchored.

The concave surfaceqof-zthelcathode is coated with "anelectron emissive material, -for example alkaline earthzoxides. The convex surface ofthe cathode may bercalorized. T

Also embedded in the press portion I4 and centrally aligned with the cathode and the arm I5 is a rigid, rectilinear wire or rod 20, which extends parallel to the cathode, is connected to one of the terminals I2 and constitutes the control electrode or anode of the device. For reasons which will appear presently, the control anode 20 is parallel to and in alignment with the cathode supports i6 and is positioned midway therebetween.

A fourth rigid, rectilinear rod or wire 2|, connected to one of the terminal prongs i2 and constituting the work or output anode of the device, is embedded in the arm I5, is aligned with the control anode 20, extends parallel thereto and is at the center of curvature of the cathode so that radial symmetry of the work anode and cathode emissive surface obtains. A portion of the work anode 2| is encased'in an insulating sleeve 22, which rests upon the arm l5 and is locked in position by a wire stub 23 Mixed, e. g.jwelded, to the anode 2!.

In the fabrication of the device, the several rigid rods or wires [6, 20 and 2! are mounted in parallel and preassigned spaced relation in a suitable jig or fixture and the press I4, I5 is formed about these wires to seal them thereto. The cathode, which is preformed to have a preassigned curvature, then is affixed to the support rods 16. It will be appreciated that inasmuch as the control anode '20 is midway between and aligned with the cathode support rods I6 any desired control gap length can be obtained by proper curvature of the cathode and that the desired control gap length is realized when the cathode is mounted upon its supports. Any desired cathode curvature is simply obtained by forming of the cathode, so that a desired control gap length is readily obtained, in effect, by a simple, accurately controllable mechanical operation.

Additionally, it will be appreciated that the cathode supports l6 together with the flanges l8 and'tabs or lugs l9 constitute a rigidly braced rugged structure. Consequently, the cathode is rigidly mounted and the requisite control gap is maintained despite shocks to which the device may be subjected during handling and operation.

, A noted heretofore, the concave surface of the cathode is coated with an electron emissive material such as alkaline earth oxides. Such oxides, as is known,'may be obtained by coating the cathode surface with a mixture of alkaline earth carbonates and. subjecting the latter to an acti vation process to decompose the carbonates and effect a conversion thereof to the oxides. The activation process comprises, in one form, in-

duction heating of the cathode to convert the lcarbonates .to the oxides and, afterevacuation' of the device and introduction of the desired gas into the vessel 10, a high frequency treatment by the application of a high frequency voltage between the cathode and work anode and then between the cathode and the control anode.

The flanges I8 assure a good coupling to the field during the induction heating and additionally, assure a uniform heating of the cathode whereby uniform activation of the entire jcathode emissive surface is obtained.

Although a specific embodiment of this invention has been shown and described, it will be understood that it is but illustrative and that various modifications may be made therein without tion as defined in the appended claims.

What is claimed is:

1. An electric discharge device comprising a gas-filled enclosing vessel having a stem, a pair of parallel, rigid linear supports embedded in said stem, an arcuate cathode extending between said supports, parallel thereto, and mounted thereon, a linear rod control anode-embedded in said stem and parallel to, fmi'dway'between and aligned with said supports, and a work anode opposite the concave face of said cathode, said cathode comprising integral transverse flanges at opposite ends thereof, extending between and substantially normal to said supports and affixed thereto.

2. An electric discharge device comprising an enclosing vessel having a gaseous filling and having also a stem which terminates at its inner end in a bi-winged portion and an arm extending from said portion, a linear rod control anode embedded in said portion adjacent the center thereof and in alignment with said arm, a linear rod work anode embedded in said armand par-- tween said supports and parallel thereto, saidcathode including spaced, transverse flanges extending between said supports and having lugs at opposite ends, said lugs being afiixed to said supports, and an electrode opposite said cathode.

4. An electric discharge device comprising an enclosing vessel having an ionizable medium therein and having also a stem, a pair of rigid, parallel supports extending from said stem, a

45 linear rod control anode extending from said stem, parallel to said supports, midway therebetween and in alignment therewith, a cathode mounted on said supports and extending parallel thereto, said cathode having a concave emissive face opposite and centrally aligned with said control anode, and a work anode opposite said face.

ROBERT L. VANCE.

REFERENCES CITED The following references are of record in the file of this patent:

STATES PATENTS Number Name Date 1,658,843 Gray Feb. 14, 1928 1,672,482 Crowley June 5, 1928 1,878,341 Spencer Sept. 20, 1932 2,053,126 Bentley Sept. 1,1936 -2,067,691" Bruijnes Jan.12,719,37 2,084,865 Penning et a1 June 22; 1937 2,103,022 Senauke Dec. 21,193! 2,263,660 Vasselli Nov. 25,1941 2,283,896 Mouromtseif et al. May 19, 1942

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