US2041595A - Electric gaseous discharge apparatus - Google Patents

Description

May 19, 1936. A. CLAUDE ELEG I'RIC GASEOUS DISCHARGE APPARATUS Filed 001;. 22, 195].

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3 Mm m m W e H Patented May 19,1936

PATENT OFFICE ELECTRIC GASEOUS APPARA mscnaaos 'rns Andi- Claude, Nanterre, France Application October 22;, 1931, Serial No. 570,45il In France November 5, 1930 4 Claims.

rare gas, and operating on the arc principle, and

which are fed by direct or alternating current, it can be appliedto apparatus of that kind which are to be used for lighting purposes.

An'object of this invention is the maintenance of integrity of the cathode in all apparatus of this type over long periods and also for maintaining the constancy of the lighting power and of the quality of the light emitted by the gaseous mass contained in the apparatus. Another object of the present invention is the. application of the means giving the above results to any electric gaseous discharge apparatus which is not used for lighting purposes, and for which it would be desirableto obtain one or several of the said results.

it is well-known that in a discharge apparatus of the herein above mentioned type working on the arc principle that although thedrop in potcn ial at the cathode is very low, a considerable amount of energy is absorbed by the cathode by reason oi the great intensity of the current passing through the device. I

The energy thus expended causes a local increase in temperature which can be sumcient to volatilize the material of which the cathode is,

In order to eliminate the disadvantages due to the vclatilization of the cathode material, the cathodic part ofthe discharge apparatus, that is to say that part of the apparatus which enshrouds the cathode, is constructed so as to form stones which, during the normal operation oi the apparatus will be at a temperature sufllciently lower than that oi the gas of the apparatus, than that of the sides of the luminous column and than that of the sides of the anodic region so that the cathodic material volatilized in the cathodic space can be condensed in the said zones. These zones however are at a temperature sumcicntly high to cause the material which has been condensed to fall in a molten state upon the body of the cathode.

The condensation zones of the cathodic part of the apparatus can be obtained by shaping elements of the cathodic part in such a manner that (A) Certain zones of these elements are less subject to the sheets of heat due to the electric energy absorbed at the cathode than others.

(B) Certain zones of these elements are colder than others, these last zones being formed wholly or partly by all or part of the zones mentioned 5 under A.

Further, a region, the normal temperature of which is considerably higher than that of the a luminous part and much higher than that of the condensation zones of the cathodic region is interposed between this latter and the luminous column. The efiects of such an arrangement is to settle the limits of the condensation zones.' It is particularly effective when the difference between the temperature of the cathodic condensation zones and the temperature of the luminous region is relatively slight.

The arrangement can be realized in different ways for example by (A) Narrowing the luminous column at a suitable point in the same.

(B) By providing a lagging sleeve reducing cooling at the walls.

(C) By providing an auxiliary heating arrangement formed for example by means of all or part of the stabilization resistance of the feed circuit of the discharge apparatus.

(D) By providing a combination of several of the above-mentioned means.

In order to eliminate the disadvantages due to the spattering of the material of the cathode, a material obstacle is interposed between the cathode and the extreme cathodic section of the illuminating part of the gaseous column, so that no particle of material emitted in a straight line from any point of thecathode can reach the illuminating part of this column.

Consequently, as the particles emitted by the cathode are mainly projected in a straight line for substantially long stretches into rare gases or mixtures of such, even in the case of the low pressures of gas used in the electric discharge apparatus, they are stopped by this obstacle which is preferably mounted in such a way that the particles return to the cathode.

By using the above-mentioned means numerous advantages are obtained some of which are cited below.

non-cathodic region of the apparatus is prevented and. con quently anyocclusion of the gas charge of the discharge apparatus through these deposits is eliminated so that on the one hand the transparency of the walls or sides of the luminous column of the apparatus is not altered and on the other hand the gaseous mass of the said apparatus is preserved unchanged.

The invention is more particularly described with reference to the accompanying drawing showing certain constructions by way of example.

,Figure 1 is an electric light discharge device constructed according to the present invention.

Figure 2 is a detailed view on an enlarged scale of the cathodic part of the apparatus according to Fig. 1.

Figure 3 is a view of a first modification of the cathodic part of Fig. 2.

Figure 4 is a view of a second modification of the same cathodic part.

Figure 5 is a third modification of the same cathodic part.

Figure 6 is a fourth modification of the same cathodic part.

In the various figures, the same reference numerals indicate the same elements.

The discharge apparatus shown in Fig. 1 comprises an anodlc part i provided with its anode l", a luminouscolumn 2 and a cathodic part 3 with its cathode an In Figure 2 the cathodic part 3 is formed by a container 4 which is concave and fairly wide, the walls 5, 6, l, and 8, 9, ill of which, not subject (or only slightly subject) to the effects of heat due to the discharge, form the condensation zones for the vapour of the cathodic material contained in the bowl or cup H. The above condensation zones can also be placed outside the cathodic region itself. They will consequently becolder than this, but sufilciently warm as stated above for causing the condensed matter to fall in a molten state on the cathode.

In Fig. 3, 42 shows a choke interposed between" the luminous column 2 and the cathodic part 3 and which forms a section is which is at a higher temperature than the temperature of the luminous column 2 and of the cathodic region.

In Fig. 4, l4 represents a member which can be either a lagging sleeve or a heating arrangement which forms a section 92 at a temperature posits tending to be projected into the apparatus a in a straight line.

In Fig. 6 the screen 51 prevents the tendency of particles projected in a straight line from the cathode, from'ialling into the tube and acts as a material obstacle to them.

It is to be understood that the various means described above and illustrated in the figures can be utilized solely or in various combinations in the same discharge apparatus.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. An electric discharge apparatus for operation under arcing conditions comprising an envelope containing at least one rare gas and divided into communicating cathode and discharge chambers, a cathode in the cathode chamber formed of metal volatile at the temperatures to which the cathode is heated by electrical energy passing therethrou'gh in the operation of the apparatus, the portion of the cathode chamber between the discharge chamber and the cathode constituting a condensing chamber and being constructed of a size sufficiently large relative to the cathode so that the walls thereof will be at a temperature lower than the boiling point and higher than the melting point'of the cathode metal, means for maintaining a zone intermediate .the discharge and cathode chambers at a temperture higher than that of the discharge chamber, and an obstacle between the cathode and the discharge chamber capable of preventing any particles of metal projected in a straight line from any point of the cathode from penetrating into the discharge chamber.

2. Apparatus according to claim 1, in which the means for maintaining the intermediate zone at a temperature higher than that of the discharge chamber consists of an electric resistance connected in series with the electric supply circuit of the apparatus.

3. Apparatus according to claim 1, in which the means for maintaining the intermediate zone at a temperature higher than that of the discharge chamber consists of heatinsulating material surrounding the apparatus at said zone.

4. An electric discharge apparatus for operation under arcing conditions comprising an envelope containing at least one rare gas and divided into communicating cathode and discharge chambers, a cathode in .the cathode chamber formed of material volatile at the temperatures to which the cathode is heated by electrical energy passing therethrough in the operation of the apparatus, the cathode chamber being constructed sufiiciently large relative to the cathode so that the wall thereof will be at a temperature higher than the fusion point and lower than the condensation point of the cathode material means for maintaining a zone intermediate the cathode and discharge chambers at a temperature higher than the temperature of the discharge chamber and a screen positioned between said zone and the cathode to prevent particles of the cathode projected in a straight line from entering the discharge chamber whereby light is emitted in the discharge chamber solely by the rare gaseous filling to the exclusion of light emitted by the material 01 the cathode.

Arman CLAUDE.

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