US1839926A - Triode vacuum tube - Google Patents

Description

Jan. 5, 1932.

l. E. MQUROMTSEFF 1,839,926

muons VACUUM TUBE Filed Jan. 7, 1925 Fig. 4.

INVENTOR Ilia E. Mouromfseff tungsten and is, therefore, more rug .mation of the filaments Patented Jan. 5, 1932 UNITED STATES.

PATENT OFFICE ILIA E. IOUBOITSEFI', O1 WILKINSBUBG,

PENNSYLVANIA, ASBIGNOB 'lO WESTING- ,HOUSE ELECTRIC 0: MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA .7

TRIODE VAGUUI TUBE Application filed January 27, 1925. Serial No. 5,078.

.mionic discharge device which is more re sistant to the electrostatic forces which tend to bend and to destroy the filament.

Another object of my invention is to prop duce a self-supporting tungsten filament cathode structure. 7

Another object of my invention is to produce a double, looped filament, cathode in which the loops are so ported at the bights thereof and also boun together at another point.

In prior construction of thermionic discharge devices, it has been customary to use looped filament cathodes. In devices adapted for the translation of high power, it has been found necessary to apply high voltages to such devices, usually rangin between- 1,000 and 10,0000)! more volts. t certain portions of the operating cycle of the device, this full voltage is impressed between the anode of the device and the filamentary cathode. Particularly in. the case of thermionic discharge devices used for rectifiers without an interposed grid structure, double this voltage is applied between the anode and cathode at certain portions of the operating cycle. The filamentary cathode is made of ed than would be the case if it were made 0 certain other metals. But in such devices, the filament is operating at an elevated temperature which may be more or less near to its softening point. It is, therefore, more readily subject to deformation than it would be at lower temperatures. A. particularly high temperature is required in order to obtain as large an electron emission as possible to cause t e device to motion in the desired manner.

The electrostatic stresses involved under these operating conditions result in a deforcathode, which may continue until the ament breaks, or

until it touches'another electrode and shortcircuits the device.

whereby the electrostatic forces impressed upon the filament may be partially c0mpensated by similar forces acting in an opposite direction. I obtain this partial compensation by a construction in which two looped filaments may be crossed at a point between the ends of the filaments and the bights of the loop and lashed together at the crossing oint.

invention will be apparent from the following description when read in connection with the accompanying drawings, wherein:

Fi ure 1 is a View in perspective of a form of amentary cathode constructed in accordance with my invention,

Fig. 2 is a diagram of a portion of a filament according tomy invention and indicating the stresses which are ap lied thereto,

Fig. 3 is a diagrammatic etch of the structure, of my invention also indicating the nature of the stresses a plied thereto,

Fig. 4 is a view, partia ly in section and partially in elevation, of a'device embodying a form of my invention, and

Fi 5 is a plan view taken on the line V-- of Fig. 4.

Referring to Fig. 2, there is indicated diagrammaticall a method of compensating the electrostatic orces accordin to a form of my invention which consists in positioning a filament diagonally within the cylindrical anode, whereby the resultant forces are in one direction at the bight ends of the filament and in another direction at the support end.

Fig. 3 showsa diagrammatic representa two filaments which are bound together by Other objects and structural details of my 'tion of the disposition of the electrostatic so My invention provides a construction the members 4 are adjacent the respective l0! ends of the two filaments which are connected to the same inleading wires and which, accordingly, have the same polarity. This construction opposes the stresses upon one filament to those in an opposite direction upon anotherfilament, and thereby reduces the effect thereof upon the filament. The filaments are connected in parallel to the supply leads, and the distance from the support wires to bindi'n wires 4, being the same for each filament, t e potential. drop is the same, and the crossing point is an equipotential point.

In Figs. 1, a and 5 are shown filaments 1 and 2, a spring supporting member 3, and bindingrmeans 4 consisting of a wrappin of wire, preferably of tungsten. An ano e 5 surrounds the v laments. A vitreous closure 6 is attached to the anode 5, by aseal 7. Closure 6 has are-entrant portion 8 and a press triode for various .ing a cathode havin J thereon through which are passed lead wires 11 and 12. To lead wires 11 and 12 are attached filament support wires 13, 14, 15 and 16 to the ends of which are attached the ends of filaments 1 and 2. The portion of my device .sofar described is adapted to be used either as a two-element rectifier or as a urposes.

If desired, a gri member may be interposed between anode and cathode as shown in lg. 4 at 17. This grid is supported in any desired manner as by longitu inal wires 18 suitably secured to a supporting band 19, which surrounds a glass member 21 sealed to reentrant portion 8 of the container 6. By this means, I am able to produce a self-supporting-cathode structure which is resistant to the deforming efiects of the electrostatic forces of the applied potential.

While I have shown only one embodiment of my invention in the accompanying drawings, it is capable of various changes and modifications without de arting from the spirit thereof, and it is esired, therefore, that only such limitations shall be imposed thereon as vare indicated in the prior art or indicated in the appended claims.

I claim-as my invention:

1. A thermionic discharge device compristwo looped filaments electrically connecte in parallel, a air of elastic supports engaging the hights t ereof, said filaments cross ng at a point between the ends and bights thereof and electrode means cooperating with said cathode.

2.- A mount for a thermionic discharge device comprising a cathode having two loo d filaments connected electrically in paralle a pair of elastic supports engaging the bights thereof, said filaments crossing at a point be tween the ends and bights thereof, and binding means uniting said filaments at said point.

3. A thermionic discharge device comprising in combination an anode, and a cathode comprising a plurality of looped filaments,

lead wires therefor, supporting means for each of said filaments at three different points, one of said supporting means comprising an elastic hook engaging the bight of said loop, and binding means attaching said filaments together at equipotential points.

4. A thermionic discharge device including a cathode which comprises two 100 ed filaments, each filament being supporte at the three )oints of an isosceles triangle, said filaments lieing so supported with respect to each other that the plane determined by the three points of sup ort of one filament intersects the plane (etermined by the three points of support of the other filament on a line between the ends of the filaments and'the bights thereof, the bases of the said triangles being substantially parallel to each other and electrode means cooperating with said cathode.

5. A thermionic discharge device including a cathode which comprises two looped filaments connected in parallel, each filament being supported at the three oints of an isosceles triangle, said filaments eing so supported with respect to each other that the plane determined by the three points of support of one filament intersects the plane determined by the three points of support of the other filament on a line between the ends of the filaments and the bi hts thereof the bases of the said triangles ing sub stantially parallel to each other and electrode means cooperating with said cathode.

6. A thermionic discharge device including a cathode which com rises two looped filaments, the ends of one 'lament being supported by members spaced apart, the ends of the other filament bein supported by members spaced apart an s aced awa from said first members, the big t of each filament bein on the side of the discharge device whic is opposite the side in which its end supporting members are located and electro e means cooperating with said cathode.

In testimony whereof, I have hereunto subscribed my name this 21st day of January,

ILIA E. MOUROMTSEFF.

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