US1904436A - Thermionic tube - Google Patents

Description

April 18, 1933.

C. S. FRANKLIN.

THERMIONIC TUBE Filed 0ct.26, 1929 lNVENTOR names 5. mums ATIORNE Patented Apr. 18, 1933 UNITED STATES CORPORATION or AMERICA, A CORPORATION or DELAWARE 'rnnmuroN c TUBE Application filed October 26, 1929, Serial No. 402,689, and in Great Britain November 2, 1928.

This invention relates to thermionic threeelectrode tubes or valves, and has for its principal object to provide an improved triode capable of being satisfactorily employed for the generation of very high frequencies.

Thermionic three-electrode valves, as at present in common use, comprise a cathode, usually consisting of a heated filament, a control electrode, usually consisting of a grid or mesh of wire or wires, and an anode, generally in the form of a plate. It is found that limitations to the frequencies of the oscillations which may be obtained with valves of this kind are imposed by the leadsconnecting the control grid system to the external circuit,

by the current carrying capacities of these leads and of the grid wires themselves, and by the inability sufficiently to cool the grid elec trode or conduct away the heat produced therein.

According to this invention the control electrode of a thermionic valve is made in the form'of a metal plate, cylinder, cone, or other solid construction, as distinct from a wire construction.

In carrying out the inventionfthe active portions of the control electrode, i. e., those I portions which mainly influence the electron flow, are formed as ribs or other projections upon a solid electrode situated on the side of the cathode remote from the anode, the said ribs or the like projecting into the cathodeanode space to any extent necessary to give a desired degree of control. The projections, which may or may not be integral with the main body of the control electrode, should be in good electrical and'thermal contact therewith.

1 The invention is illustrated in the accom- 40 panying schematic drawing, in which Figure 1 is a sectional elevation and Figure 2 a sectional plan of a so-called transverse construction of valve in accordance with the invention. Figure 3 is a section showing the construction of the control electrode incorporated in the valve shown in Figures 1 and 2.

Referring first to Figures 1 and 2, a valve 1 V shaped anode forming one portion of the comprises a disc-shaped metal anode A opposite which is concentrically mounted a solid disc-shaped metal control electrode G,

K therefor being brought through. the glass,

which is provided with slots or grooves S in which are arranged filament portions F as shown. The'electrodes A and G are separated and supported by glass parts M to which the appropriate electrodes are fixed by 5,15; suitable vacuum seals. The filament. portions may be in series, parallel or series-" parallel, as ,may be desired, the connections as shown in Figure 1.-

v Aswill-be seen, the electrodes are in socalled transverse arrangement, both control electrode and anode being in the-form of. disc-like members. The control electrode; G is formed with slots or grooves S in which Q5, are arranged the filament portions F, as

clearly shown in cross-sectional Fig. 3.

It will be seen that the present inventionprovides a valve in which both the anodeand' the control'electro-de maybe of ample current 7Q carrying capacity, while both these electrodes may be arranged to be cooled by oil or similar mediums. Further, the difficulties hitherto experienced in making adequate connections to the control electrode are mini- 7i. mized or obviated.

1. A thermionic tube comprising a disc-'- shaped anode, a disc-shaped grid electrode adjacent and parallel to said anode, the grid Q9 electrode being provided with grooves, an electron emitting electrode positioned within the said grooves and a cylindrical member open at each end, interposed between and having its ends joinedlto said anode 5.

and grid electrodes.

. 2. A thermionic tube comprising a discshaped anode forming one portion of the tube envelope, a disc-shaped grid electrode positioned opposite to said disc-shaped 9,9 anode and forming another portion of the tube envelope, an electron-emitting element mounted between said grid and anodeelectrodes, and'means interposed'between sald disc-shaped gridand anode electrodes maintaining said electrodes in spaced relation.

3. A. thermionlc tube comprlsing a disctube envelope, a disc-shaped grid electrode and forming another portion of the tube envelope, a cathode mounted between said grid and anode electrodes, and a glass p0rti0ninterposed between said disc-shaped grid and anode electrodes maintaining said e1ec--- trodes in spaced relation, both said electrodes and the glass portion being the sole means comprising the tube envelope. CHARLES SAMUEL FRANKLIN.

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