US1879471A - Gaseous electric discharge device - Google Patents

Description

Sept. 27; I932. M. PlRANl ET AL GASEOUS ELECTRIC DISCHARGE DEVICE Original Filed Aug. 19 1929 THEIR A TTORNE y 1 umn would break in ing hollow body,

' ing point, since Patented Sept. 27, 1932 UNITED STATES PATENT OFFICE mARcELLo PIRANI, or IBERLIN-WILMERSDOR F HANS nwus'r, or IBERLI-N, Ann ALFRED RUTTENAUER, or BERLIN-CHARLOTTENBURG, GERMANY, ASSIGNOBS T0 GENERAL ELECTRIC comu NY, .A CORPORATION or N W YORK GASEOUS ELECTRIC DISCHARGE DEVICE Application filed August 19,1929, Serial No. 387,057,

and in Germany August 21, 1928. Renewed January 29, 1931.

The present invention relates to electric discharge devices useful in the arts generally, and' particularly as electric lamps.

eretofore, in electric discharge lamps with gas or vapor filling and with a view to obtaining a steady urning, or to obtaining another light color, and preferably a white light color, of the gasor vapor discharge, it has been proposed, among other things, to mount in the interior of the lamp chamber for the guidance of the gas or vapor dis charge, a tubular body of insulating material, such as refractory oxides, which was supposed to be raised to a red heat by the discharge and thus cause the desired light rad iation. The placing of such a guide tube light emitter in the discharge path, howev er, has been found very inefficient as the guiding tube absorbs or shuts off all or most of the light from the gas or vapor discharge. Furthermore, because of the relatively small dielectric strength of such material it is not possible to build up the current density of the discharge high enough-to attain the desired results.

' The use of metallic, conducting, solid walled hollow bodies for the hitherto proposed insulating material making up the guiding hollow body has hitherto never been tried, or the opinion was that the light colsuch a current conductand also that the current conductor used would only be brought to a red heat.

It has been discovered, however, that the foregoing opinion is not correct and that the positive column of the discharge, probably under the influence of the wall charge, goes freely. through a current conductor ticularly a metallic hollow body.

In the new devices hereinafter described and using a solid wall hollow body-of current conducting, high melting point material in particular a metal having a high meltdielectric strength naturally does not come in question, increased current density and therewith increased light density are obtained in the operation of the de b vice. Also any suitable high melting point gaseous and parsolid walled hollow body, as it can easily be made of uniform thickness over its entire length, while with a hollow body consisting of insulating material the wall thickness is not evenly uniform and it may be more or less porous. The greater uniformity and homogeneity of the new hollow body consisting of high meltingpoint conducting material has not hitherto been. attained in previous devices and perfect uniformity of surface brightness is now attained for the first time and which is very essential for the use of such'lamps as projection means and for crack illumination.

A more essential advantage, in particular a much smaller light absorption takes place, if the new conducting guiding hollow body is provided with holes or perforatlons throughout its entire length. Such a sievelike conducting hollow body allows not only a large part of the light from the gas or vapor discharge to go out unhindered through the openings, but also is itself charged w1th perfect uniformity in all its parts by virtue of' its good conductivity when the lamp 1s trically charged mesh of the hollow body, it is probable that a space charge is created which prevents the transfer of the gas or vapor column through the openings of the hollow body, The gas or vapor discharge 1s thus positively confined within the hollow body, and also in a narrow space therem. This, in connection with the high heat durability ofthe hollow body, permits the current density of the discharge to be raised.

very high.-

Finally, as the perforated current conducting hollow body. by virtue of its essentially I small radiating surface has only a small heat radiating loss, thus it follows that with an equivalent applied current an extremely higher current density of the discharge is secured.

The new perforated and conducting hollow body can consist of thin metal plates with punched perforations or of crossed ands or wire, it can furthermore be in the shape of cylinders or prisms. The openings or mesh of the conducting hollow body must of a hollow bod in a tube shape made of a provided with chambers of conducting ma,-

quartz,

mesh ofrmolyb enum or tungsten wire net or corresponding wire web, only about 10% to 20% of the light of the gas or vapor column is hidden from view and therefore a higher temperature equilibrium is very easily produced and maintained.

It has also been discovered now that if, in addition to the aforesaid arc confining tube of conducting material extending between the electrodes, the discharge tube is further terial surrounding the electrodes instead of ones made of insulating material and heretofore thought necessary in a discharge device of this type, that an electric field is created around each electrode which, in the operation of the device, confines the discharge to the electrodes in exactly the same manner that the discharge is confined within the hollow tubeextending between the electrodes and, furthermore, results in reducing the potential required to start the device into operation and permits of its operation on 110 or 220volts commercial circuits and at greater current and light densities than, when insulating electrode chambers are used.

The present invention is illustrated in'the accompanying drawing in which Fig. 1 is a sectional elevation of a gaseous electric discharge device of our invention and. Fig. 2 is a similar view ofan alternative embodimen'tl In the drawing, 1 is a' container of glass, or other suitable material containing gases or vapors or mixtures thereof, such gases being, for example, nitrogen, carbonic vacid gas, neon, helium, argon, mercury, etc.

Container 1 is provided with stems 3, 3 on which are mounted the electrodes 8, 8 consisting wholly or in part of material having high electron emissivity. The sealed in current leads 5 for the said electrodes 8. are arranged inside two concentric insulated tubes 24, 27 which rest on the base 3 and support a plate 25 which, in turn, supports the electrode 8. Surrounding the electrodes 8 are two chambers 10, 10' of conducting material, such as metal, one end thereof 11' be ing sprung over the stem 3 by means of the split portion 31 and resting on ring 29 on the stem 3. The other end of said chambers 10' have openings facing toward the opposite electrode and a tube 16 oftungsten wire net,-

. or other suitable material, is attached to the ends 12, 12' of said chambers 10' and support the said net 16 in its position surroundby the useing the gaseous dischargepath between the electrodes. I I

When desired, pointed pins 30, 30 of con ducting material, metal, for example, are mounted in the chambers 10 and having their-pointed ends extending into close proximity to the electrodes 8, 8 as shown in the drawing and the number of such rods is optional.

It is, of course, understood that the member 16 may be made of other material than tungsten and can consist of a web of nonconducting oxide rare earths, for example, thorium oxide, cerium oxide or scandium oxide which is made conductive by the im-' pregna-tion of molybdenum or other suitable conducting material.

In operation, the use of a sievelike conducting body surrounding the gas or vapor pathpermits the major part of the light from the gas or vapor discharge to pass unhindered through the openings and is itself charged with perfect uniformity inall its parts by virtue of its good conductivity, when the lamp is put into operation. \Vith reference to the electrically charged mesh 16 it is probable that a space charge is created which prevents the transfer of the discharge through the openings of the enclosing tube.

The metal enclosing chambers 10 like the member 16 are electrically charged and form an electric field around each electrode which, in the operation of the device, confines the discharge to the electrodes in exactly the same Way that the gas or vapor discharge is confined Within the web 16.

The device above described, is found to be operable at high current densities wherein the tungsten wire network 16 is heated to an intense white heat, the radiations from the tungsten or other conducting body being added to those of the as or vapor discharge and the device there ore can be used as a lamp for illumination or as a generator of ultraviolet or other rays by using a material permeable to the rays, visible or invisible, generated within the device.

An advantageous feature attendant upon the use of chambers of conducting material about the electrodes and the conducting web 16' about the current path is that the starting resistance of the tube, shown in the drawing, is materially reduced and it is now possible to start and operate such gaseous electric discharge devices with a light column of about 0.50 m. in length on commercial c1rcu1ts of Ill 110 or 220 volts without the use of high current starting impulses and consequently without the use of transformers for generatrents of the greatest densityare desired as is the case when using the new. lam

ps' as beacons. -In thls figure,

a tube seal structure is shown having a large current carrying which is screwed into capacity in which the cap 32 of conducting material is hermetically sealed into the end of the container wall 1 and the electrode 8 is mounted on the inner end of the rod 33 the top ofthe cap 32. A supporting member 35 rests on the inner side of the cap 32 and is held in place thereon by a nut 34 on the ,rod 33, the support member 35 serving to hold the chamber member 11' in place. Tlfe rods 13, 13, if desired,may be used to aid in supporting the chambers 10, 10. Y

We claim:

- 1. In an electric discharge device, a container, electrodes sealed therein, a gaseous filling therein, a tubularbody of conducting material surrounding the discharge path between the electrodes, and chambers of conducting material surrounding said electrodes.

2. In an electric discharge device, a container, electrodes sealed therein, a gaseous ling therein, a perforate tubular body of conducting material surrounding the dis-- charge path between the electrodes, and chambers of conducting material surrounding said electrodes.

3. In anelectric discharge device, a con.- tainer, electrodes sealed therein, a gaseous filling therein, a tubular body of conducting material surrounding the discharge path be tween the'eleetrodes, and chambers of conducting material surrounding said electrodes, said tubular body consisting of wire mesh.

4. In an electric discharge device, 'c0ntainer, electrodes sealed therein, agaseous filling therein, a tubular body of conducting material surrounding the discharge path between the electrodes, and chambers of conducting material surrounding said electrodes,

said-tubular body consisting of wire mesh comprising non-conducting and conducting materials. v r

5. In an electric discharge device, a container, electrodes sealed therein, a gaseous filling therein, a tubular body of conducting material surrounding the discharge path between the electrodes and pointed pins mounted on-said disc arge surrounding members and extending toward said-electrodes.

trodes to a value such that'the voltage of the 110 volt commercial circuit on which said lamp is designed to operate is sutficient to initiate the desired operation of the lamp. 7. A positive-column electric lamp comprising a container, electrodes sealed therein and a gaseous atmosphere therein, the electro-motive force on which said lamp is to operate being of .a value insuflicient to overcome the resistance to startingexisting at said electrodes and in said discharge column, and an oelement of conducting material within said container surrounding said electrodes and the discharge path between them for reducing the resistance to current flow between said electrodes to a value such that the voltage of the current on which said lamp is designed to operate is sufiicient to initiate the desiredoperation of the lamp.

8. A positive'eolumn electric lamp comprising a container, electrodes sealed therein, a gaseous atmosphere therein, and an element of conducting material surrounding each of said electrodes and the positive column discharge path between said electrodes and out of contact with said electrodes for reducing the'resistance to current flow between said electrodes to a value such that the voltage of the current on which said lamp is designed to operate is suflicient to initiate the desired operation of the lamp.

9. A positive column electric lamp comprising a container, electrodes sealed therein, a gaseous atmosphere therein,'and an element of conducting material extending from electrode to electrode and along the positive column discharge path between said electrodes andout of contact with-said electrodes for reducing the resistance to current flow between said electrodes to a value such that "the voltage of the current on which said lamp is designed to operate is sufiicient to initiate the desired'operation of the lamp.

In witness whereof we have hereunto set our hands this 5th day of August, 1929.

MARCELLO PIRANI. HANS EWEST. ALFRED RUTTENAUER.

6. A positive column electric dischargelamp adapted to operateon 110volt commercial circuits comprising a container, electrodes sealed therein and a gaseous atmosphere therein, the electro-motl've force on which said lamp is tooperate being of a value insuflicient to overcome starting existing at said said discharge column, and an element of conducting material within said container surrounding said electrodes and the disthe resistance to charge path between them for reducing the resistance to current flow between said elec electrodes and in

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