US2042057A - Electron discharge device - Google Patents

Description

A. s. HOPPING ELECTRON DISCHARGE DEVICE Filed June 14,

PPM/4 I O 3 0 u E .v ,N w L A 35 awe W Patented May 26, 1936 UNETED STATES PATENT OFFIQE ELECTRON DISCHARGE DEVICE Application June 14, 1929, Serial No. 370,786

11 Claims.

This invention relates to thermionic devices and with particularity to electron discharge tubes of the multi-electrode type.

The principal object of the invention is to pro- 5 vide an electron discharge device or repeater which is highly efiicient in operation and economical of manufacture.

A feature of the invention relates to an electron discharge tube suitable for use as an amplifier,

10 detector, etc. wherein the usual anode, cathode, and control grid are provided and, in addition, according to the invention a member is provided surrounding the anode to shield the control grid from the anode potentials.

15 Another feature pertains to a four-electrode tube wherein one of the electrodes serves as a shield and completely surrounds the remaining electrodes.

A further feature resides in a four element tube having a central cathode and a plurality of concentrically spaced electrodes together with a means for supporting said electrodes whereby the said supporting means is symmetrically disposed with relation to all the electrodes.

25 A still further feature resides in the manner of supporting and assembling the electrodes of a four element discharge tube whereby the electrodes are accurately and permanently spaced from one another.

30 Other features and advantages not specifically enumerated will be revealed after a consideration of the following description and appended claims.

Referring to the drawing- 35 Figure 1 thereof is a vertical view partly in section of the electrode assembly and support means therefor according to the invention with only a portion of the evacuated envelope being shown;

40 Fig. 2 is a side elevation, partly in section of the electrode structure and assembly shown in Fig. l, with one of the coiled grids omitted;

Fig. 3 is a view showing the outer shielding electrode according to the invention;

Fig. 4 is a detailed sectional view of the electron emitting cathode and heater therefor;

Fig. 5 is a sectional view of the structure shown in Fig. 1 and taken along the line 5-5; and

Fig. 6 is a top plan view showing the upper 50 electrode-spacer element according to the invention.

Referring more particularly to Figs. 1 and 4, the numeral I represents a heater element of the looped filament type which passes through suit- 55 able bores in the insulating tube 2. Tube 2 in the well known manner carries on its outer surface a metal sleeve 3 which is coated throughout a portion of its length withany suitable electron emitting material. The ends of the filament I are brought out at the lower end of the tube 2 and are welded to corresponding filament support and lead-in wires 4 and 5, respectively, which pass through the press portion 6' of the tube I, and symmetrically with respect to the center line thereof.

For the purpose of supporting the cathode assembly the cathode sleeve 3 is provided at its lower end with an extension or tab 8 which is welded or soldered to a support and lead-in rod 9 which preferably passes through the central portion of the press 6. symmetrically disposed with relation to the support 9 and on either side thereof are provided two rods I0 and II, respectively, to the upper ends of which are welded the supporting rods I2 and I3, respectively, for the coiled shielding grid I4. Grid I4 is preferably in the form of a helically wound wire having the turns spaced and welded to rods I2 and I3. Instead of making the rods I9, I2, and II, I3 in two pieces it is clear that a continuous piece of the same material may be used and bent to the proper shape. Welded to the lower end of the rods I2 and I3 is a metal ring I5 on the upper edge of which is adapted to rest a disc I6 preferably of mica or any desirable insulating material. As shown more clearly in Fig. 5, said disc I6 is provided with holes therein through which pass the rods I2 and I3, and also on the opposite diameter said disc is provided with holes to receive the ends of the supporting rods I! and I8 (Fig. 2). Rods I1 and I8 act as supports for the turns of the helical controlling grid I9, said turns being preferably welded to said supporting rods I1 and I8 in like manner to the grid I4 described above. As shown clearly in Fig. 2 the grid I9 rests upon the disc I6 and is accurately spaced concentrically with relation tothe cathode 3 by means of the holes in said disc. Connection to the grid I9 is made by means of conductor 20 which may be brought out through the top portion of the envelope.

Similarly, for the purpose of accurately spacing the upper end of the cathode and the two grids I4 and H a mica'disc 2| (Fig. 6) is provided having holes fO-r receiving the upper ends of the two sets of rods I2, I3 and I1, I8. Said disc is also provided with a central cut-out portion for receiving the cathode assembly. Symmetrically disposed with relation to the center of the press 5 and on either side thereof is another set of support rods 22, 23 which are welded to corresponding upwardly extending rods 24, 25. Rods 24, 25 serve as supports for the cylindrical plate electrode 26, said plate being preferably welded to said rods 24 and 25 in the manner shown clearly in Fig. 5.

For the purpose of completely surrounding and shielding the cathode 3, the controlling grid I9 and the plate 26, there is provided a cylindrical member 21 Which' may be made from sheet metal, or preferably, of wire gauze, as shown in Fig. 3. The shielding member 21 is supported from the press 6 by means of the two symmetrically disposed rods I and II, described hereinabove, to which is welded the laterally extending supporting frame 28. Frame 28 is likewise welded or in any other manner fastened to the member 21.

For the purpose of maintaining the member 27 in a concentric position with respect to the cathode assembly the upper end of said. member 27 is provided with a circular metallic cap 29 which is preferably welded at its turned-down edge to said member 27. As shown in Fig. 1 the cap 29 is provided with two hollow projections 30 and 3| registering with the insulator sleeves 32 and 33 which are supported on the projecting ends of the rods 24 and 25, respectively.

From the foregoing description it will be seen that all the electrodes are symmetrically positioned with respect to each other and that the support wires for said electrodes are likewise symmetrically positioned within the press portion .6. The support wires may, therefore, be mounted in the same plane, thus reducing the chances of breakage or leakage in the press which would be likely to occur if said support Wires were sealed in an unsymmetrical manner in said press. Furthermore the cathode support and lead-in wire may be brought out through the center of the press. It will also be observed that the plate electrode 26 is shielded on its inner surface by means of the coiled grid I4 and is also shielded on its outer surface by means of the cylindrical mesh 21 which are interconnected through the rods III, I I and the member 28. As a result of this symmetrical disposition of all the lead-in supporting wires and as a result of the fact that all the conducting elements of the tube are mounted within the circumference of the member 27 and symmetrically disposed with respect thereto, the shielding action of said member 21 ismore uniform than would be the case where certain of the lead wires or support wires are brought outside of the shielding member. Likewise the fact that the support Wires are in alignment and symmetrically disposed within the press portion 6 enables the entire assembly to be more readily manufactured by automatic machinery.

One manner of assembling the tube is along the following lines. The press 6 has sealed therein in any well known manner the seven supporting rods shown in Fig. 1. The cathode assembly (Fig. l) including the heater filament l, is positioned centrally above the press and the tab 8 is welded or soldered to the support rod 9. The. ring I5 is positioned symmetrically with respect to the cathode assembly and the mica disc I6 is then passed overth'e cathode until it rests on the upper edge of said ring. The coiled grid I9 is then assembled concentrically with respect to the cathode 3, sothat the lower ends of the supporting rods I! and I8 pass. through the corresponding holes in the disc I6 (Fig. 3). With the grid I9 properly located, the lower projecting ends of rods I I and I8 may be bent to prevent dislodgment thereof. Likewise the coiled grid I4 is next positioned so that the lower ends of the rods I2 and I3 pass through the corresponding holes in the disc I6. With both grids thus assembled about the cathode the ring I5 may be welded to the rods I2 and I3 and also to the support rods I ii and II. The plate 26 is next assembled and its supporting rods 2 1 and 25 are welded at their lower ends to the offset ends of the supporting rods 22 and 23 respectively. The

insulator sleeves 32 and 33 are next positioned over the upper projecting ends of the respective rods 24 and 25 and the cap 29 is positioned so that the raised'portions 3B and 35 rest on the said insulator sleeves, as shown clearly in Fig. 1. The mica disc 2I is then assembled in position with the upper ends of rods I2, I3 and I'I, I8 projecting therethrough and the upper ends of said rods are bent over, as shown in Figs. 1 and 2, to maintain the adjusted relation of the parts. The screen member 21 is then placed in position and welded to the turned down edge of the cap 29 and also to the member 28. A suitable exhaust tube 3G is connectedto the flare 35 of the press by means of which the tube 1 may be exhausted.

What is claimed is: I

1. An electron discharge device comprising a cylindrical cathode, a control grid surrounding said cathode and comprising an upright wire around which the grid is wound, an anode electrode surrounding said grid, a pair of metallic uprights supporting said anode, and projecting beyond the upper end thereof, and another cup shaped electrode surrounding said anode and insulatingly supported on the projecting ends of said pair of uprights, said cylindrical cathode being centrally supported within said grid.

2. An electron discharge device having a press, a cylindrical anode provided with a pair of metallic uprights for supporting the same, the lower ends of said uprights being sealed into said press and the upper ends projecting beyond the end of the anode, insulator beads mounted on said projecting, ends, a cup shaped electrode surrounding said anode and supported by said beads, and a tubular cathode supported from said press concentrically with relation to said anode and said electrode. V

3. An electrode arrangement for an electron discharge device comprising a press, a series of three spaced concentric cylindrical electrodes, the intermediate electrode serving as an anode and the other electrodes serving as shields, a pair of metallic uprights for said anode, said uprights having their lower ends sealed into the press, the upper ends of said uprights projecting beyond the anode, .a pair of metallic uprights for the inner cylindrical electrode having their lower ends sealed into the press, and a metallic cap closing one end of the outer cylindrical electrode, said cap being. supported on both said pairs of uprights,,said cap being in electrical contact with the uprights from the inner electrode and being insulated from the uprights for the anode.

4. An electrode arrangement according to claim 3 in which thersaid cap isprovided with a central perforation and supports a disc of insulation also having a perforation registering with the cap perforation.

5. In an electron device, the combination of a plurality of electrodes, an electrically conductive plate fixed to one of said electrodes, a plurality of electrically conductive members fixed to another of said electrodes, and a plurality of insulators interposed and in engagement with both said plate and said members for supporting the same in fixed relation to each other.

6. In an electron device, the combination of a plurality of cylindrical electrodes, an electrically conductive annular plate fixed to one of said electrodes, said plate having a recess therein, an electrically conductive member fixed to another of said electrodes, and an insulator on said member and seated in said recess adapted to support said plate and said member in fixed relation to each other.

'7. In an electron device, the combination of a plurality of electrodes, an electrically conductive plate fixed to two of said electrodes, an electrically conductive member fixed to another of said electrodes, and an insulator interposed between said plate and said member for supporting the same in fixed relation to each other.

8. In an electron device, the combination of a plurality of cylindrical electrodes, an electrically conductive annular plate fixed to one of said electrodes, said plate having recessed therein a plurality of electrically conductive members fixed toanother of said electrodes, and a plurality of insulators one on each said members and seated each in one of said recesses adapted to plate fixed to two of said electrodes, a plurality of electrically conductive members fixed to another of said electrodes, and a plurality of insulators contacting with both said plate and said members for supporting the same in fixed relation to one another.

10. In an electron device, the combination of a plurality of cylindrical electrodes, an electrically conductive annular plate fixed to two of said electrodes, a plurality of electrically conductive members fixed to another of said electrodes, and a plurality of insulators contacting with said plate and each one of said members for supporting the same in fixed relation to one another.

11. In an electron device, the combination of a plurality of electrodes, an electrically conductive plate fixed to one of said electrodes, said plate having a recess therein, an electrically conductive member fixed to another of said electrodes and extending to a point near said plate with an end of said member juxtaposed to said recess, and an insulating cap fitted over said end of said member and inserted in said recess in said plate.

ALVIN S. HOPPING.

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