US2018071A - Short wave tube - Google Patents

Description

INVENTORS DIETRICH PRINZ ATTORNEY l llli s wxLHELM EBERHARD KUHLE j Ej) BY www W. E. KHLE ET AL SHQRT WAVE TUBE Filed Sept. 29, 1954 oct. 22, 1935.

- Patented Oct. 22, 1935 UNITED STATES PATENT ori-"ICE,

SHORT WAVE TUBE wilhelm mmm xm ma 'Diemen Berlin,

Prinz aaaignora to Telefunken Ge:

Germany lellscliaft fr Drahtlose Telemphie m. b. H., Berlin, Germany, a corporation of Germany Application September 29, 1934, Serial No. 746,215

In Germany October 7, 1933 4 Chlml. (Cl. Z50-27.5)

a closure and supporting means in the form of a' plate or disc and corresponding to a press into l5 which several concentric metal tubes may be hermetically sealed by annular seals very little if at all longer than the thickness of the disc, and to unite the ceramic and the tube envelope with a vacuum-tight connection. In the fin- 20 ished structure rings of ceramic-insulating material are positioned between the metal tubes or leads and the overall length ofthe closure and supporting member is a minimum.

The novel features which we believe to be g5 characteristic of our invention are set forth with particularlty in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which 30 Figure l is a longitudinal cross section of an electron discharge made in accordance with our invention; Figure 2 is a longitudinal cross section of a modification of the electron discharge device shown in Figure 1 and embodying our invention; 35 and Figure 3 shows a detail of construction.

. In Figure 1 the tubular metal anode envelope l has positioned within it the grid-2, and the cathode 3. The electrodes 4, 5, and 8, in the form of concentric tubes, are supported in spaced rela- 40 tion by concentric ceramic rings 1, i, and 9, which, with the ceramic plug l in the base of the tubular conductor 6, form a flat or disc-like inset plug corresponding to a press in a conventional tube. The leads are extended perpendicu- 45 lar from the closure and supporting member into the envelope, and form in the space outside the envelope a co-axial tubular system which is free from radio frequency radiations. The electrodes are supported within the metal envelope solely 50 by the leads. By choosing a suitable length for the tube, conditions can be made so that a voltage node will be set up at the closure member of insulating material, whereas a. voltage loop is formed at the lower end of the electrode sys- 55 tem. An arrangement of this kind has the advantage that' only slight dielectric losses take place in the insulation material forming the closure member. It will be seen that leads and l which support the cathode can be removed as a unit, in the event a replacement is necessary, by 5 unscrewing lead 5, to which lead l is secured by member l, from the tubular member il which is internally threaded to receive lead 5. An exhaust tube i2 is embedded preferably in the outer annular member 1. It may be desirable in some cases to employ a cathode such as shown in Figure 2, comprising so-called twin or double prism lamentary cathodes i5 and i6 each consisting of three or more spaced parallel current-carrying filaments connected together at their ends so that they lie in the edges of an imaginary prism. The filaments which denne a pair oi prisms are all interconnected at the' bottom as shown and supported solely bythe lead conductors. As a result, no central rod is required for supporting the cathode, thereby eliminating the possibility of such a rod forming an oscillatory system with the electron emitting laments of the cathode.

To make good seals between the ceramic insulating members and the tubular leads molybdenum tubes, which have proven especially suitable, are preferred. inasmuch as it is diillcult to make seamless molybdenum tubes, it is preferable to make them by riveting the edges of sheet I nolybdenum together, the riveting being done as best shown in Figure 3, only along the edges of the tube i1 not embedded in the ceramic insulator.

A tube formed by riveting the edges of the molybdenum sheet together in this way may then be smply fused to the ceramic insulator, provided the molybdenum tube has a suiliciently thin wall.

While we have indicated the preferred embodiments of our invention of which we are now aware and have also indicated only one speciilc 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 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 isz- 1. An electron discharge tube for use at high frequencies and comprising a tubular metal envelope open at one end, member of ceramic material closing the open end of said envelope, a plurality of concentric tubular leads imbedded in said member, and electrodes supported solely by said leads within said envelo 2. An electron discharge tube for use at high frequencies and comprising a tubular metal envelope open at one end, a member o1' ceramic material closing the open end oi said envelope, a plurality oi concentric tubular lead conductors imbedded in said member and supported in spaced relation with each other and with the envelope by said press. and electrodes supported on said lead conductors within the envelope.

3. An electron discharge tube for use at high frequencies and comprising a'tubular metal envelope open at one end, an inset plug of ceramic material closing the open end of said envelope, a plurality of concentric tubular lead conductors imbedded in said inset plug, and electrodesincluding a cathode comprising a plurality o! parallel maments arranged to denne a pair of prisms supported by said lead conductors within the envelope.

4. Anl electron discharge tube for use at high frequencies/ and comprising a tubular envelope open at onev end, a :dat inset plug o! ceramic materia] closing the open end of the envelope. a plurality of concentric tubular lead conductors imbedded in said inset plug and comprising tubes made of thin molybdenum sheet extending pei-V pendicularly from both sides of said inset plug with the edges or the tube riveted together only on the extended portions of the tube, and electrodes supported on said lead conductors within said envelope.

WILHELM EBERHARD Kimm. DIETRICH PRINZ.

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