US1682642A - Incandescent cathode - Google Patents

Description

Aug. 28, 1928. 1,682,642

B. VAN DER POL- INCANDESCENT GATHODE Filed May 11, 1925 I I I I I V I 1 f x /5 IE/ L46 6/ w 7 r L 0 1 Patented Aug. 28, 1928.

UNITED STATES PATENT OFFICE.

BALTHAZAB VAN DER POL, OF EINDHOVEN, NETHERLANDS, ASSIGNOB TO N. V. P HILIPS GLOEILAMPENFABRIEKEN, 0F EINDHOVEN, NETHERLANDS.

INCANDESCENT CATHODE.

Application filed May 11, 1925, Serial No. 29,526, and in the fletherlands Kay 21, 1924.

This invention relates to incandescent cathodes for transmission tubes, which incandescent cathodes are heated by an electric current, more particularly to incandescent cathodes for transmission tubes of comparatively large outputs.

In transmission tubes for wireless telegraphy or telephony or in rectifiers, there are often used incandescent cathodes which havethe shape of a hair-pin. If the current in the filaments used for this purpose becomes comparatively heavy, which is the casein transmission tubes of large outputs, the electrodynamic forces acting on the parts of the filament increase to such a degree that these parts take other shapes under the influence of said forces; the two legs of a hairpin-shaped filament, for example, are bent outwards.

According to the invention, .in order to obviate said disadvantage the incandescent cathode consists of a number of substantially parallel parts, which are so arranged relatively to each other and to one or more leading-in wires which are parallel to each other and to the parts of the filament, that the electrodynamic forces acting on the incandescent cathode substantially neutralize each other. i

According to the invention two parts of the filament and two leading-in wires may be arranged substantially parallel to each other so as to pass through the angular points of such a rhombus that the distance between the leading-in wires a r ranged diagonally opposite each other is 3 times the distance bet-ween the parts of the filament. The four elements are further so arranged that the electric currents have substantially-the same value and that'the direction of the currents passing through the two parts of the filament is the same, but is opposite to the direction of the currents traversing the leading-in wires.

The accompanying drawings illustrate by way of example some embodiments of the invention. In the said drawingfl Figure 1 shows a construction of an incandescent cathode in which two parts of the filament and two leading-in, wires are arranged parallel to each other.

Figure 2 is a plan of the incandescent cathode with its support as shown in Figure 1.

Figure 3 is a sectional view of a rectifier arrows) comprising an incandescentcathode accordto Figure 1. f

According to Figure 1 the support of the incandescent cathode consists of a metal clip 1, which has two parallel parts 3 and 4 and is carried by a conductor 2. To the upper connecting piece of the clip a metal rod 5 is secured which carries parts 6 and 7 of a filament which are suspended so as to be, parallel to each other and to the leading-in wires 3 and 4. The other ends of'these filaments are secured to a clip 8 which is carried by a conductor 95 It is clear from the drawing that the currents passing through the wires 3 and 4 have the same direction, but have an opposite direction compared with the currents traversing the wires 6 and 7 (see the The distance between the wires 3 and 4 must be about 3 times the distance between the filaments 6 and 7.

The electric discharge tube shown in Figure 3, which may serve to rectify alternating.

currents, is provided with an incandescent cathode of the same construction as is shown in Figures 1 and 2. The conductors 2 and 9 are secured to metal hoods 10 and 11 which at their edges are hermetically sealed to glass tubes 12 and 13, which again archermetically sealed to a glass vessel 16. On their other sides the metal hoods 10 and 11 carry leading-in wires 14 and 15. A metalvessel 17 which serves as anode is heremetically sealed to the end of a glass vessel 16.

What I claim is r 1. A cathode for a discharge tube comprising a pair of parallel lead-inwires, a' pair of parallel filament wires parallel to the said lead-in wires and connections so that the current in each pair of wires is in the-same direction.

2. A cathode for a discharge tube comprising a pair of parallel lead-1n wires, and lead-in wires also serving asa filament support, a pair of parallel filament wires, and connections so that the current in each pair of wires is in the same direction.

3. A cathode for a discharge tube comprising a support substantially rectangular in shape and of conducting material, a leadin connection to said support, a cross bar.

secured to said support, parallel filaments of parallel filaments parallel to said arms,

and an electrical connection between one end of the parallelarms and the adjacent end of the filaments adapted to cause the current to flow in opposite directions in the lead-in arms relatively to the' current in the filaments. 1

5. A cathode for discharge tubes compris in a lead-in wire forming a loop with parthe arms being adapted tosupport a filament, said filaments bein arallel to each other and to the arms, and t e opposite end of the filaments being electrically connected to a second lead-in wire.

7. A cathode for discharge tubes comprising a plurality of conductors each adapted to carry equal amounts of current in the same direction, a lead-in connection to one end of said conductors, and a plurality of filaments one end of which is connected to the other ends of the conductors and adapted to carry equal amounts of current in the same direction, and the other end of the filaments connected to a second lead-in wire.

In testimony whereof I affix my signature, at the city of Eindhoven, this seventeeth day of April, A. D. 1925.

BALTHAZAR VAN DER POL.

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