US2003012A - Grid glow tube structure - Google Patents

Description

May, 28, 1935. P. SASHOFF GRID GLOWV TUBE STRUCTURE Filed May 27, 1933 TTbRN Y Patented May 28, 1935 GRIDiGLOWJTUBE STRUCTURE s phanl ii-gsa ho fiG e v e, Ela-{a s ntof Westinghouse Electric & Manufacturing.Com

at Pittsburgh, Pa., a corporation o nn v i npplicatr imayev, iss'a'se ialrr zcvazer y claims." (01150-27551, My invention'relates to an electrical discharge device and particularly to a hot-cathode'gaseous discharge tube. I I

An object of my invention is'to provide an '5 electric discharge tube, that shall be capable of direct use as a relay utilizing commercialvoltprovide an anode'structure fora discharge tube that isrugged'incharacter, which is simple and economical to manufacture, as well'as effective and reliable in'opera'tion. I a

Further objects. of my invention will become apparent from the following description when taken in connection with the" accompanying drawingyinwhich, r i

:Figure 1 is aiview in vertical sectional elevation of aspace discharge device embodying my invention, and

2'is-"an'enlarged view, partly in section, looking down from the line II--II of Fig. l.

The tube shown in Fig. 1 comprises the usual bulb or container 1 supported on a conventional base member 2 from which project the usual prongs 3 for the exterior connections of the tube. A press and seal 4 of conventional form supports the connection from the exterior prongs 3 to the interior elements of the tube. In the center of the glass press 4 is an upward projecting refractory insulating sleeve 5 which may be integral with the glass press 4. The upward projecting sleeve 5 is adapted to surround the connection 6 to the anode l for the purpose of increasing the ohmic resistance between the supports of the various electrodes of the tube. The sleeve 5 has preferably an exterior cylindrical surface.

The anode I may be of any suitable material, such as nickel, iron or molybdenum, and is pref erably made in the form of a segment of a spherical surface. This anode may be screw threaded tothe top of the connection 6 or otherwise secured thereto.

Sleeves 8 and 9 of refractory insulating material also project upwardly from the press 4 to surround the metallic connections If! and l I which project to the upper part of the tube from two of the prongs 3. When desired sleeves 5, 8 and 9 may be non-integral with the press 4. A conventional thermo-emissive cathode l2, which may be of tungsten or of a nickel-cobalt alloy such as Konal, coated with electron-emissive' oxide, is connected across these two connections away therefrom. For gaseous discharge tubes,

electron in the gaseous atmosphere.

ranging all the way from a" magnitude of one and is adapted to be heated to an electron-emissive state by current'pas'sed through from the connections wand H. '1

Projecting -upward through the press! aretwo metallic standards 13, i4, one of which is 8 connected to the prong of the base '2 constituting thetgri'd terminal. -At their upperends they-Q support a number of members l-5--'of insulatin g material, 'such;- forexample, as quartz pwhich' may be in the form ofanannular disc with a 1t) hole at itscenter closely fittinggthe sleeve '5. The insulating member 15 may be supported on the standards 13, I4 by suitable collarsabo've and. below it,'.which may, if desired, bescrewthreaded or pinched on the standards I3, 14. I} The insulating member l5 is preferably so positioned that it .fits against the lower edge of the spherical anode land projects to form a ledge or rim extending radially outward at the lower edgeofsaidanode. f 1 p a 2 A control electrode I6,: preferably intheform' of a segmentof a spherical surface of perforated metal or woven-metalscreen, is positionedto. substantially cover. the spherical surface of. the anode I and may be uniformly spaced radially itwill usually be desirable to make this radial spacing less than the mean free path of an The control electrode I 6 may advantageously extend down to the edge of .the insulating plate l5, and may preferably be bent over and clinched in place mechanically uponthe edge of the plate l5. An electrical connection from the edge of V the control electrode I 6 may extend to thestandard I4 which is to constitute the grid lead.

The discharge tube structure above described may be exhausted toa vacuum of such degree as to permit only a pure electron discharge at its intended operating voltage by methods'well known in the art, such as those described in Langmuir Patent 1,558,436. Both the anode 1 and the control electrode I6 may, if desired, be carbonized in accordance with Upp Patent 1,852,865; While the above-described tube struc- 45 ture is useful for electron tubes operating by pure electron discharge, it has been found especially useful in tubes having a substantial gaseous atmosphere present, such as'those described in Knowles application, Serial'No. 149,290, filed November 19, 1926, assigned to the Westinghouse Electric & Manufacturing Company. Gaseous atmospheres, comprising the noble gases, or mercury vapor or mixtures thereof, at pressures atmosphere down to vacuums which permit only pure electron discharge, are. within the scope of my invention; Y

For many" purposes, it will'be found desirable to arrange the press 4 with two or more intersecting fins I! like the cross indicated in the top view of theanode and control electrode structure shown in Fig 2. 'With s uchjan arrangement, it may .be desirabletoprovide additional standards I8,-l9 set in the press 4 at the lower ends and supporting theplate I5, in the same manner as standards I3 and I4 at their upper ends. a

The structure above described has beenfo'und' to be peculiarly valuable through its'permanence, ruggedness, rigidity of structure, constancy of spacingland alignment, and ease and cheapness of manufacture. The insulating sleeves 8 and 9 will be seen to provide long insulating creepage distances between conductors likely to'be at great differences of electrlcallpotentialand, accordingly, adapt. tubes of the structure described toemployment with higher voltages and power outputs than tubes of the priorv art. The substantial, area" and heat-radiating surface of both the anode! and the control electrode l6, together with the form, of the cathode in which permits;

it to be of relatively largesize andsurface area, also ,facilitatethe construction of tubes of rel: atively large currentoutput.

. In accordance with the ,patent statutes, 1 have "describeda particular embodiment of thebroad" principles 'of myinventionbut these principles are capable .of applicationin other .;ways which will be evident to those skilled. in the art. I, ac; cordingly; desire .the following claims to be. given thebroadest interpretation of which their terms are susceptible in view of theprior art.

I claimias'my' inventionz.

1. An electrical discharge device comprising a vacuum-tight container, a press, a cathode supported onleads-projecting above said press, insulating sleeves encasing said cathode leads for a substantialdistance above said press, an inleading wire sealed through said press and projecting upward therefrom, a sleeve of insulating material about saidwire, and an anode connected to the upper end of said wire-adjacent the top of said insulating sleeve and substantially enclosing the top of said sleeve.

2. An electrical discharge device comprising a vacuum-tight container, a press, a cathode supported on leadsprojecting above said press, insulating sleeves encasing said cathode leads for a substantial distance above said press, an inleading wire sealed through said press and projecting upward therefrom, a sleeve of insulating material about said 'wire and an anode connected to the upper end of said wire, the last-named insulating sleeve covering substantially the entire length of said wire between said press and said anode, said anode having an annular edge portion extending a wire, sealed through said container, a sleeve of insulating material about said wire and an anode connected to the upper end ofsaid wire, the said insulating sleeve covering substantially the entire length of saidwire between said container and said anode, said anode having an annular edge portion extending a substantial distance below the upper end of the said insulating sleeve, a control electrode of perforated metal enclosing the external surface of said anode, and insulation adjacent the lower rim of said'anode surface forming a barrier extending across the entire distance from said insulating'sleeve to said control .elec-' trode.

' v STEPHAN P. SASHOFF.

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