US2355718A - Electrical discharge device - Google Patents

Description

Aug. 15, 1944. w. w. EITEL ET AL ELECTRICAL DISCHARGE DEVICE Original Filed Feb. 14, 1941 2 Sheets-Sheet 1 INVENTORS WILL/AM w. E/TEL BY 05% A. ggwueh THEIR ATTORNEY Aug. 15, 1944. w. w. ElTEL ET AL 2,355,713

ELECTRICAL DISCHARGE DEVICE Original Filed Feb. 14, 1941 2 Sheets-Shet 2 fig -5 IE L E' INVENTORS WILL/,2 PV- E/ EL THEIR ATTORNEY T 7 BY dig AgUijOl/GH Patented Aug. 1 5, 1944 23 5.71 ELECTRI AL DISCHARGE DEVICE William'W; Eitel and Jack A. McCullough, San I Bruno; Calif., assignors to 'Eitel-McCullough; 1 Inc., San Bruno, -C alif., a corporation of California Original application February 14, 1941, Serial No. 378,900. Divided and this application October 10, 1941, Serial No. 414,506 a 3,.Claims. (01. 2501-275) 7 ,l In greater detail," and'refje'rring to Figure 1 of the drawings, onet'ype of two-unit tubeem;

bodying the improvements of our invention com This is a division of our copending application, Serial No. 378,900, filed February 14, j19 4'l.""

Our invention relates to electron discharge devices; and. more particularly to thermionic tubes.

It is among the objects of our inventionto' provide an improved multiple-unit tube wherein several operative units are assembled'within a single envelope, and in which'the individual units are designed with electrode spacings approximating the ideal in regard to transit time efiects, electron migration, interelectrode capacity, and thermionic efliciency.

Another object is to provide improved means,

for mounting and supporting the electrodes within the envelope. Still another object is to provide iinproved means for connecting like electrodes of 'thejunits in parallel for simultaneous operation,

The invention possesses other' object s' "and: features of advantage, some of which, with the foregoing, will be set forth in the following,

description of our invention. It is to beun'derstood that we do not limit ourselves tothis' dis closure of species of our invention, as we may adopt variant embodiments thereoivrithinthe scope of the claims.

Referring to the drawings:

Figure 1 is a side view, partly in section a id.

partly in elevation, showing a two-unit tube embodying the improvements. ofpur invention};

and

Figure 2 is an exploded view of the same illuse trating the electrodes mounted on the several envelope sections.

Figure 3 is a fragmentary view showing a modified construction in which 'the anodes are unitarily supported; and v} Figure 4 is a horizontal sectional view taken in a plane indicated by. line 4-4 of Figure 3.'

Figure 5 is a side view, partly in section and partly in elevation, showing another modified two-unit tube; and

Figure 6 is a similar view of a four-unit tube.

Figure '7 is a horizontal sectional view taken in a plane indicated by line 1-1 of Figure 6.

In terms of broad inclusion, our electrical discharge device comprises a plurality of units mounted within a single envelope and each including a plurality of electrodes such as cathode, grid and anode. Improved means are provided for mounting the electrodes of the several units, and improved means are provided for establishing electrical connections with the electrodes.

prises an envelope ofvitreous material such as intermediate"portion' including a reduced'neck 3, and a shoulder lyand ailower end portion including a reentrantstem B. -Th'e base 'of the tube" comprises a' porcelaincollar 1 secured to the neck by cement 8 and carrying'iour terminals or prongs 9 three of which are shown in Figure 1. i

The two units are preferably disposed'symmetrically about the axis of the tube; and each comprises a set of electrodes including a cathode or filament l I; a grid or control electrode I2, and ananode or plate 13. ,Cathodes II are supported from stem 6 by conductors l4; grids l2 from shoulder 4 of the intermediate tube portion by conductors l5; andanodes [3 from dome portion-Z by conductors [6. These supporting leads are all sealed in the'tubeportions indicated and provide external connections for the various electrodes. The-mounting of the grid supports a-t-shoulder 4 instead of in 'the base ofythe tube materially reduces the interelectrode capacities atfthebasey Cathodes ll may be of any'suitableform, such as the coiled filaments illustrated; one filament being connected to one pair of terminals spy on-a flat lportion ofthe envelope, so that the external portions of the grid leads project downwardly within the limits defined by the main body of the envelope.

Anodes 13 may be of any desired construction, but better results are secured by using the particular type shown. The anode is hollow and preferably cylindrical in shape, and has a series of say three radiating fins 20 disposed circumferentially about the electrode and extending transversely of the electrode axis. The axis referred to is the longitudinal axis about which the cathode and grid are also disposed. Our anode is preferably made from drum-like sections having integrally formed, outwardly extending, an-

nular flanges to provide fins, of double thickness when the sections are secured together.

The anodes of the tube type shown in Figure 1 are separately supported on leads I6, each anode being fastened to its lead by a strap 2| secured to a cap 22 of the electrode. These supports being separate from the independent of the heat radiating fins 20 tend to thermally isolate the anode; which is desirable for the purpose of keeping the glassseal at the support from undue heating. Separate external connections can thus be made to each electrode of each unit, so that one unit may be operated independently of the other.

For simultaneous operation the anodes are preferably connected in parallel to a common central lead 23 as shown in Figures 3 and 4. In this case a bracket is provided with lateral fins 24 embracing the lead and with base flanges 26 secured to the upper fins of the anodes. Fins 24 extend upwardly along lead 23 and decrease in width ther'e along. These fins aid in radio frequency conduction, and also function to dissipate heat.

Figure 5sh0ws another two-unit tube having units'adapted for simultaneous operation and illustrates improved means for establishing con-' nections with the grids.' The grids are connected in parallel by a. terminal element or ring 21 of metal having a button 28 and secured to the envelope by a suitable cement 3|. The terminal ring is of L-shaped section having a flange underlying the horizontal annular ledge 'of the shoulder, and grid leads l5 are connected to the ring flange by welding to lips 32. This ring construction at the shoulder through which the grid leads 'are sealed is an effective means for making connection with the grids, and provides a sound mechanical constructionof good appearance.

Figure 5 also shows a variant type of anode mounting employing anodes 33 having ordinary longitudinalfinsfl. Fins 36 of the supporting bracket embrace conductor 31 and lap the inwardly extending fins on the anode so that the brackets form an extension of the anode fins. Here' again the bracket fins taper down toward their outer ends. Thebase structure and cathode connections of this tube are preferably similar to that'shown in Figure 1, since both cathodes may be simultaneously energized by making proper c'onnections with terminals 9.

v Figures 6 and 1 illustrate a four-unit tube of a construction similar to that of Figure 5 but embodying four complete units instead of two. The

' four anodes are all connected in parallel to the common support 31. and the four grids are connected in parallel to ring 21. The cathode connections in this tube are made to the four base terminals 9 by connecting two of the filaments in parallel to a pair of terminals by leads 38 and 39, and connecting the remaining two filaments in parallel to the other pair of terminals by leads 4| and 42.

The method of assembling the electrodes in the envelope to insure accurate alignment and spacing is as follows: With reference to the tube type shown in Figure 1, for example, and referring particularly to Figure 2, our method comprises forming the envelope in a plurality of say three separate'sections corresponding to the three portions previously referred to herein; namely, an upper end section including dome 2, an intermediate section including neck 3 and shoulder 4, and a lower end section including stem 6. The cathode structure is mounted on the stem section, the grid structure on the intermediate section, and the anode structure on the dome section. By this arrangement the several electrode structures may be readily and accurately fabricated on suitable jigs. The envelope sections are then fused together; the lower and intermediate sections being preferably fused first to enable proper alignment of the cathode and grid structures before the dome section is sealed in place.

Our multiple-unit tubes in which the units operate in' unison give excellent results. Many unsuccessful attempts have been made in the past to produce large tubes having the high oper ating efficiency characterizing tubes of small physical size. In our improved tubes where several small operative units are assembled within a single envelope, the individual units are designed with electrode spacings approximating the idealin regard to transit time effects, electron migration, interelectrode capacity and thermionic efficiency. Ourtubes are extremely easy to drive; provide a high power output at low plate voltage; and the small interelectrodel capacities enable them to operate effectively at ultra high frequencies.

We claim:

1. In an electrical discharge device, a plurality of separate electrodes of similar function, an envelope enclosing the electrodes and having a shoulder, an external terminal ring disposed on the envelope adjacent the shoulder, and conduc-' tors for the electrodes extending through the envelope at the shoulder and connected to said ring.

2. In an electrical discharge device, an electrode, an envelope enclosing the electrode and having an annular shoulder providing a fiat ledge, an external terminal ring disposed on the envelope adjacent the ledge, and a conductor for the electrode extending through said ledge and connected to the ring.

3. In an electrical discharge device, an electrode, an envelope enclosing the electrode and having an annular shoulder providing a fiat ledge, an external terminal ring of L-shaped section disposed on the envelope at the shoulder and having a flange portion underlying said ledge, and a conductor for the electrode extending through the ledge and connected to said flange.

WILLIAM W. EITEL. JACK A. MCCULLQUGH.

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