US2098380A - Gas discharge device - Google Patents

Description

2 Sheets-Sheet l A. ENGELMANN El' AL GAS DISCHARGE DEVICE Filed July 13, 1957 www wf@ ATTORNEY Nov. 9, w37.

Noy.-9, 1937. A. ENGELMANN ET AL GAS DI SCHARGE DEVICE Filed July l5,A 1937 2 Sheets-Sheet 2 |NVENTO ALFRED ENGE GUNTHER W www ATTORNEY l metal layers, or in whose depressions they have trodes are arranged such that owing to openings Patented Nov. 9, 1937 GAS DISCHARGE DEVICE Alfred Engelmann and Gnther Wolf, Berlin, Germany, assignors to Telefunken Gesellschaft fr Drahtlose Telegraphie m. b. H., Berlin, Germany, a corporation of Germany Application July 13, 1937, SeralNo. 153,328 In Germany July 19, 1936 Figure 1, Figure 3 is an enlarged developed-section of the outside of the ceramic envelope shown in Figure 1, Figure 4 is a section along III-:III of Figure 3, and Figure 5 is a vertical section of a portion of a modied form of our invention.

Examples of constructions of tubes according to the invention are represented in the drawings. In Figure 1 the cylindrical ceramic vvessel l is closed on all sides, the wall being cut on the outside by notches or grooves 2. The notches have steps'- or bars rising from the center line to both sides in a stair-like fashion. The steps between the notches thus have a cross section similar to'a stepped up pyramid. The deepest notch; cuts through the entire wall thickness and forms the aperture or slot 3 between which only individual bridges 4 remain in order to keep the lentirestructure together. The bridges remaining between the notches need not have the throughgoing cross section represented in Figure 1. The highy est bar is preferably almost cut away `Save a few supporting noses or studs 5 such as seen from the cross section represented in Figure 2, and from the development shown in Figure 3 of the tube of Figure 1.

There is placed over the ceramic cylinder` .I- and its supporting noses (or supportingv'bars) `kan ano-de cylinder 6 of metal to t as-exactly as possible, and fused or soldered vacuum tight atits ends to the ceramic cylinder. The anode 6-may-. be provided on the outside with bridges or ribs l. The anode 6 is surrounded by a second metal cylinder 8 spaced from the anode, and the cylindrical hollow space thus obtained is closed up water tight by two annular plates 8' at the ends so that; by means of two short tubings 9 and Illa suitable cooling means can be passedl Vtherethrough 'for cooling the anode.

The steps of the notches -21 have the emission grid and the control grid applied as metallicJ layers l l and I2. The distance between the electrodes is established through the supporting noses or bars 5 and through the height of the step and distance from the anode. ASince ceramic parts can without difficulty be ground to anA accuracy of 0.001 mm., the requiredv small distances can thus be accurately adhered to during manufacture. Ceramic bodies change their form substantially not at all even at high operating temperatures, the heat expansion remainingA far below the allowable limits. A tube according to the invention thus can be produced correctly with an accurate manufacturing method, and affords a reliable and steady operation. Owing to a high stability as regards heat effect, large 6 Claims.

Our invention relates to improvements in electron discharge devices of the gaseous discharge type.

The hitherto known constructions. of gas tubes have not been a success in View of the fact that the anode in the system could either absorb only a very low power loss, or led to heat levels of the "structure of the system which rendered the grid structures in close vicinity of the anode useless. Another diiculty is that a certain temperature level must be maintained for the tube, in order continually to maintain the most favorable conditions of vapor pressure for the tube.

It is known to produce parts of tubes of ceramic masses. Also the electrode system itself has already been produced of ceramic bodies, on which the electrodes have been arranged in the form of been embedded.

In gas tubes, special conditions prevail as compared with the high vacuum electron discharge tubes. The electrodes, particularly where continuous grid control is desired, must .be disposed very close to each other-in general at a distance less than l mm. or a distance of the order of the mean-free-path of an electron in the gas-and they must at the same time withstand large currents. In the constructions hitherto known, grid electrodes have been used which were mainly supported at the edges. The heat produced during operation resulted in deformation which rendered the operation of such tubes unreliable to a certain degree.

The principal object of our invention is to provide an improved electron discharge device of the gaseous discharge type.

In accordance with the invention there is tted into or onto a metallic anode a ceramic body by means of attached noses or bars, the ceramic body having stepped parts, notches, grooves or the like in which or upon which at least two further elecin the ceramic body, they permit the passage of electrons, while having a distance from each other that is too short for an ionic or gas discharge therebetween.

The novel features which we believe to be characteristic of our invention are set forth with particularity in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawings in which Figure 1 is a vertical section of an electron discharge device made according to our invention, Figure 2 a transverse section along the line II-II of powers can be controlled While only a small space is required. The discharge vessel is closed up by means of a cover I3 preferably likewise consisting of ceramic material joined in the conventional manner vacuum tight with the other parts of the tube, and which may at the same time also contain the lead-ins I 4 and I5 to the emission grid and control grid. The sections of grid I I may be electrically connected by straps II and the sections of grid I2 by straps I2' extending through the step portion of the ceramic tube wall. Item I5 is the thermionic iilament cathode which may of course also be of some other form, for instance an indirectly heated cathode.

Figure 3 shows a plane development of the ceramic body I of Figure 1. Tlievfigu're shows a' top view or outside of the anode side. The refer-H ence characters have the same significance as in the preceding iigures.

Figure 4 shovvs Ythe section alongline III-III of Figure 3.

The principlev of the invention above-described on hand of an example may be modified in various ways. Instead of metallizing on the body i the electrodes by means of electrolysis, or chemical reduction, deposition by evaporation or cathode atomizing, or the like, or by other methods, they may also be provided in the form of wires, bands, or metal mesh. Such perforated electrodes may also be placed over the entire notch,

so that the electrons must permeate the electrodes. Such a case is shown in Figure 5. When using metallized layers, coats may also be applied to the radial Walls of the slots 3, as indicated in Figure 4.

The notches proper may also have a different form. In particular itis possible to provide further steps for the support of further grids.

`Furthermore the notches may be formed as Vcoherent screw line, in which case the individual electrode parts need no longer be joined together individually.

The anode may be cooled with water, oil, or air. In place of the cooling by Way of circulation as shown, a cooling by way of boiling may also be used. The artificial cooling aifords of establishing an operating temperature independent of the load.v

The principle of the invention may finally also be applied to amplifiers for head current.

Forthe anode a metal resisting mercury is best suited such as nickel, iron, chromium nickel, or chromium iron.

While We have indicated the preferred embodiments of our invention of which We are now aware and have also indicated only one specic application for which our invention may be employed, it will be apparent that our invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations f' may be made in the particular structure used and the purpose for Which it is employed Without departing from the scope of our invention as set forth in the appended claims.

What We claim as new is:

1. An electron discharge device including anenvelope of ceramic material, said envelope having a slot extending through the wall of said envelope, a metallic electrode positioned on the outside of and sealed to said envelope and closing said slot, a thermionic cathode filament Within said envelope and a control electrode supported in the Wall of said envelope in registry with said slot and out of contact with the electrode outside of said envelope.

2. An electron discharge device including an envelope of ceramic material having slots extending through the Wall thereof, a metallic electrode on the outside of said envelope and hermetically sealed to said envelope over said slots, a thermionic cathode within said envelope, the wall of said envelope being provided with a groove on the outside surface of the envelope and superimposed on said slot and a control electrode supported in said groove out of contact with the electrode outside of said envelope.

3. An electron discharge device including an envelope of ceramic material having a plurality of slots extending through the wall of said envelope, a plurality of grooves on the outside of said envelopeV superimposed on each of said slots, an electrode on the outside of saidenvelopeland her- 'metically sealed to said envelope over said slots,

a pair of control electrodes supported by said grooves in spaced relationship and out of contact with the electrode on the outside ofthe envelope.;

4. An electron discharge device including an elongated envelope of ceramic materialwhaving transverse superimposed stepped grooves in the wall of said envelope and slots registering with said grooves and extending through the wall of said envelope, a pair of controlmembers supported in said grooves in spaced relationship and a metallic anode member surrounding and sealed to the envelope over said grooves and slots,i and a cathode within said envelope.

5. An electron discharge device including a cylindrical envelopeof ceramic material containing a gaseous medium, a cathode Within said envelope, said envelope having `a plurality of transverse slots extending around and through the wall of said envelope and spaced longitudi-4 nally along said envelope, said Wall having on the outside thereof stepped grooves registering with said slots, a cylindrical anode member surrounding said envelope on the outside thereof and sealed to said ceramic envelope 'over said grooves and slots, and a ,plurality of control electrodes supported Within said grooves in spaced relationship with each other and said anode a distancenot greater than the mean-free-path of an electron in said gas for controlling the iiow of electrons from said cathode to said anode.

6. An electron discharge device including a cylindrical envelope of ceramic material containing a gaseous medium, a cathode Within said envelope, said envelope having a plurality of transverse slots extending around and through the wall of said envelope and spaced longitudinally along said envelope, said walls having on the outside thereof stepped grooves registering with said` slots, a cylindrical anode member surrounding said envelope on the outside thereof and sealed to said ceramic envelope over said slots and grooves, and a plurality of control electrodes supported Within said grooves in spaced relationship with.

each other and said anode a distance not greater than themean-free-path of an electron in said gas for controlling the iiow of electrons from said cathode to said anode, and a cooling -jacket surrounding said anode. f

AIiFRED ENGELMANN. GNTHER WOLF.

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