US2094680A - Gaseous electric discharge device - Google Patents

Description

GASEOUS ELECTRIC DISCHARGE DEVICE Filed Dec. 31, 1936 INVENTOR Pie'ber- Schouwsfr-a ,3 mg I iifioi y Patented Oct. 5, 1937 UNITED STATES- PATENT QFFICE Pieter Schouwstra, Eindhoven, Netherlands, assignor to General Electric Company, a corporation of New York Application December 31, 1936, Serial No. 118,645

In Ge 2 Claims.

The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to such devices comprising an elongated container having elec- 5 trodes mounted adjacent the ends thereof and a body of an electrically conducting material extending along the discharge path between said electrodes to facilitate the starting of the discharge in said device.

A strip of electrically conducting material, such as graphite or precipitated silver, applied as a coating on the outer surface of the container wall and connected to a current source is effective for starting the discharge in such devices. Such l5 coatings frequently crumble or rupture under service conditions and thus become less efiective for starting purposes.

The application of such coatings to the confronting exterior surfaces of the closely adjacent legs of a U-shape container for a discharge lamp, which is the most advantageous location for such light obstructing coatings, is difiicult and expensive.

The object of the present invention is to pro-' vide a rugged, inexpensive, adherent, flexible, electrically conducting strip for facilitating the starting of the discharge in an elongated container of a gaseous electric discharge device. Still further objects and advantages attaching to the device and to its use and operation will. be

apparent to those skilled in the art from the following particular description.

In accordance with these objects the starting strip of the present invention comprises two or more straight parts contiguous with the outer surface of the container which parts are connected by a resilient bent part which, when compressed, exerts a force suiiicient to hold said straight parts firmly against the surface of the container. The starting strip of the present invention is particularly useful for U-shaped discharge devices. The strip is mounted between the legs of the container with the straight parts thereof pressing against one leg and the bent part thereof pressi: -g against the other leg.

Frequently in the fabrication of U-shaped tubular containers the distance between the legs thereof is different in individual lamps and the legs are not always in exact parallel relation.

Under conditions of service of the discharge device the distance between the legs changes due to th-.- expansion and contraction of the con tainer. A starting strip made in accordance with the present invention is capable of adapting itself 5 to containers of different configurations and to many December 21, 1935 the changes in the distance between the legs of the container during the operation of the device so that a good contact between the starting strip and the container wall is always maintained.

When the discharge device is of the type operating with an elevated container temperature, such as a temperature of 200 C. or more, the glass wall of the container conducts electricity during the operation of the device. Electrolysis frequently takes place at the parts of the container in 10 contact with the starting strip and the container becomes softened at said parts which terminates the life of the lamp. It is, therefore, advantageous to interpose a high heat resisting, insulating material between the starting strip and the con- 15 tainer to prevent such electrolysis.

In the drawing accompanying and forming part of this specification an embodiment of the invention is shown in a front elevational view.

Referring to the drawing the gaseous electric 20 discharge device comprises an elongated, tubular, U-shaped container I having a thermionic electrode 2 sealed into each end thereof and having a gaseous atmosphere therein comprising a rare gas, a metal vapor, or a mixture of starting gas 25 and metal vapor, such as a mixture of neon at a' pressure of approximately 1 to 10 mm. and sodium vapor. The container has therein a quantity of sodium which vaporizes during the operation of the device. Said electrodes 2 are electron 30 emitting when heated and consist of a coiled filament, such as a tungsten filament, having another filament wrapped around it and a coating of electron emitting material, such as a barium oxide on said electrode. tainer l are connected by the curved portion 6. A starting strip 3, 4 consisting of electrically conducting material, such as nickel, and which is several millimeters in width is mounted between thelegs of the container I. Said strip 3, 4 con- 40 sists of a plurality of straight parts 3 which press against one leg of said container l and a plurality of bent parts 4 which press against the other leg of said container so that the starting strip is firmly held in position between the legs 45 of said container l. The starting strip 3, 4 is connected by lead 5 to a lead of that electrode 2 mounted in the leg of the container other than that leg against which the parts 3 of said strip are contiguous. 50

Preferably an electrically insulating, high heat resisting material is interposed between the container I and the strip 3, 4 to prevent electrolysis of the glass container I. When desired, the strip 3, '4 consists of an enamelled spring steel ribb n,

The legs of the U-shaped con- 35 a or of aluminum the surface of which is oxidized.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention, for example, the curved part 6 of the container l is provided with a metal strap which is connected to the strip 3, 4 to act as an auxiliary, starting electrode, when desired, or, when desired, an auxiliary electrode is sealed into the container I at the curved part 6 thereof, which auxiliary electrode is connected to the strip 3, 4.

What I claim as new and desire to secure by Letters Patent of the United States, is:-

1. In combination, a gaseous electric discharge device comprising an elongated, U-sharied; tubular container having a gaseous atmosphere therein and electrodes sealed therein adjacent the ends thereof and a strip of electrically conducting material interposed between the legs of said container and extending along the discharge path between said electrodes to facilitate the starting of the discharge in the device, said strip comprising a plurality of straight parts connected by a resilient bent part, said straight parts pressing against one leg of said container and said bent part pressing against another leg of said container.

2. In combination, a gaseous electric discharge device comprising an elongated, U-shaped, tubular container having a gaseous atmosphere therein and electrodes sealed therein adjacent the ends thereof, a strip 01 electrically conducting material interposed between the legs of said container and extending along the discharge path between said electrodes to facilitate the starting of the discharge in said device and .a body of material having good electrical insulating properties at elevated temperatures interposed between said strip and said container, said strip comprising a plurality of straight parts connected by a resilient bent part, said bent part, when compressed, exerting suflicient force to support said straight parts firmly against the wall of said container.

PIETER SCHOUWSTRA.

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