US1390456A - Electric-arc lamp with rotary arc. - Google Patents

Description

y L. MAUCLAIRE, A. GARBARINLAND G. GAUTIER.

ELECTRIC ARC LAMP WITH ROTARY ARC.

APPLICATION FILED ocr. 23, 1917.

1,390,456. Panasept. 13, 1921.

^ UNITED STATES PATENT OFFICE.

LOUIS MAUCLAIBE, ANDR GARBARINI, AND GEORGES GAUTIER, 0F PARIS, FRANCE.

ELECTRIC-ARC LAMP WITH ROTARY ARC.

Specicatidll of Letters Patent. Patented Sept. 13, 1921,

Application med October 23, 1917. Serial No. 198,170.

To all whom. z't may concern Be it known that we, Louis .MAUCLAIRL ANDR GARBARINI, and GEORGES GAUTIER, citizens of the Re ublic of France, residing in Paris, France, have invented certain new and useful Improvements in Electric-Arc Lamps with Rotary Arcs, of which the following is a speciication.

This invention relates to improvements in the construction of electric arc lamps with a rotaryl arc, used for the production of light, for the production of electric oscillations, and for all other purposes.

Embodiments of the invention are illustrated in the accompanying drawings.

In said drawings,-

Figure 1 is a view, principally diagrammatic, illustrating one embodiment of the present inventio Figs. 2, 3, and 4 are illustrative diagrams illustrating the action of the magnetic fields upon the arc.

Fig. 5 is a view similar to Fig. 2, illustrating another embodiment of the invention.

Fig. 6 is a view illustrating an embodiment of the invention in a form' somewhat more developed than in Fig. 2.

Figs. 7, 8, `and 9 are cross-sectional views of electrodes provided with aspiration conduits for drawing oif combustion products in the vicinity of the arc.

The improvements in are lam s according to this invention have for t eir object to provide a lamp in which the rotating arc is stabilized by the use of two groups of coils or solenoids separate one from the other; further, the central carbon which is used is prevented from burning away prematurely by the arrangement of a refractory member into which the carbon passes, while the same member surrounds com letely the space between the central electrode and the annular electrode. The centralcarbon employed is moreover provided with an internal passage or passages rendering it possible to draw away the fumes produced bythe burnin of the arc.

In te lamp which forms the sub'ect of the present invention, the arc is sta ilized by usn e two groups of coils situated at O1 and y (Fig. 1), that is to say-in front of and behind the are. The line of force produced by this combination of two grou s of coils 4has the form indicated by t e line Z in Fig. 1, In this case when the are plays correctly between the central electrode C and the annular electrode B, that is to sayfrom a .to b, it cuts the field normally, and consequently a single cou le is exerted on the arc causingit to turn. I the arc tends to play rearwardly between a1 and b1 or for wardly between a2 and b2, it will cut the line of yforce in a variable direction.

Incase the arc plays Abetween a1 and b1 (Fig. 3) it will be seen that in addition to the couple acting on the arc and causing it to turn, there will be a force tending to move the arc-forwardl depending upon the angle a: which the `line Z makes with res ct to the normal n. In the case shown in ig. 3, that is .to say during perfect working, the

normal n is coincident with the line of force Z. If the arc plays between a? and b2 (Fig. 5) the normal n makes an an le with the line of force L which results 1n the production, in addition to the motive couple producing rotation of the arc, of a force tending to move the arc back to the points a and b which correspond to normal working.

The two groups of coils O1, O2 might be arranged to have, one with respect to the other, a preponderating action in view of the fact that the lamp is intended to be used for purposes requiring a very great intensity of light in a single direction, or even for industrial purposes for which it is de sired to obtain an emission of light which is substantially constant in all directions (see Fig. 5).

Another disadvantage which exists in lamps with rotating arcs as hitherto known, results from the fact that when the arc is caused to play between the central electrode C and the annular electrode B, there is a violent movement of air which supports the combustion of .the carbon C from the part g (Fig. 5) to the part h i, this latter part in the only one which is useful, that 1s to sayt e crater. l

Owing to this using up of the carbon, which causes the electrodel C to taper in a conical form, the section of the carbon between the points h i becomes much smaller than the sea'tion at f g which is the normal section of the carbon.l Under these conditions the burning away of the carbon is very rapid, as the section of .the carbon which is really utilized, is not the whole section of the carbon employed, but a very much reduced Y section dened by the crater h i, .In order to prevent this abnormal using up of the carbon, according to this invention an insulating member A (Fig. 6) is arranged behind the annular electrode B and bearing against this electrode, the member A being formed with a central hole for the passage of the electrodev C. This insulating member A, which must be capable of withstanding high temperature, is covered internally with a layer D consisting of a mixture of rare earths and of thoria. With this arrangement the electrode C still becomes cut away at the end to a conical form, but to a comparatively slight extent as Fig. 7 shows, the points lrs belng much nearer to the points c d.

Moreover, as the section of the carbon at the points 1' and s is very little different from the section at the points 0 and d, if the closure effected by the member A is perfect, the following phenomenon takes place: Before the arc is started the chamber E is filled with air; when the arc is lighted this air allows a very slight combustion of the electrode C to take place, but after a very short time the chamber E will contain only gaseous oXid or carbon, which is the only body stable at this temperature. The arc as it continues to pass thus plays in an atmosphere which does not permit any unusual burning away ott the electrode C', the part c d alone7 which constitutes the crater, being in a state of very high incandescence.

When the lamp is to operate at a very high intensity, or when the electrode C is placed very close to the crater of the arc of optical appliances such as lenses, mirrors, condensers and so forth, said electrode C always produces some objectionablevapors. When such a lamp is employed with a projector for example, it is found necessary to have recourse to devices intended to protect the mirror from the fumes produce-d, and a glass plate is generally inserted between the arc and the mirror.

When the lamp is to be used for the purposes indicated above, an electrode C is employed, according to the present invention, formed with a small internal passage x (Fig. 6), while t-he end of the electrode distant from the crater is connected to a fiexible pipe leading to an aspirator of any suitable kind.

With this arrangement, all the fumes produced by the combustion of the electrode C are drawn into the passage formed in this electrode and are thus removed. In addition to the great advantages of' this method of aspiration in removing vapor and dust particles, another important advantage is secured resulting from the fact that the vapors and fumes are very hot, so that as they pass through the interior of the carbon they heat and dry the same; this has the effect of improving considerably the regularity of the burning of the lamp. It

is well known that when carbon electrodes are moist their operation is very defective. Various arrangements of the passages may be used for drawing away the vapors and fumes; for example, homogeneous carbons may be used having central longitudinal passages (Fig. 7) or in carbons having cores of a dil'erent composition, the passa-ge may be formed in the interior of the core (Fig. 8) or two, three or more passages may be arranged around the circumference of the core (Fig. 9), while of course the c0mposition of the carbons themselves can be varied according to the uses to which they are to be put.

Claims:

1. An arc lamp of the revolving arc type comprising a central carbon electrode and a surrounding annular electrode, and two separatedsolenoids whereby the rotating arc is stabilized, said solenoids being substantially concentric with the axis of said central electrode.

2. An arc lamp according to claim 1, in which the solenolds are arranged in planes on opposite sides of the plane of the annular electrode, and one has a preponderant effect over the other.

3. An are lamp of the revolving arc type comprising a. central carbon electrode and a. surrounding annular non-consumable electrode, having an insulating member, said insulating member in conjunction with said annular electrode forming a chamber inclosing the space within the annular electrode on the side on which is mounted the central electrode.

4. An arc lamp of the revolving arc type comprising a central carbon electrode and a surrounding annular non-consumable electrode, having an insulating member, said insulating member in conjunction with said annular electrode forming a chamber inclos ing the space within the annular electrode on the side on which is mounted the central electrode and a refractory layer on said insulating member.

5. An arc lamp of the revolving arc type comprising a central carbon electrode and a surrounding 'annular non-consumable electrode, having an insulating member, said insulating member in conjunction with said annular electrode forming a chamber inclosing the space within the annular electrode on the side on which is, mounted the central electrode and asp-irating means for drawing gases of combustion from said chamber. t

6. An arc lamp of .the revolving arc type comprising a central carbon electrode and a surrounding annular non-consumable electrode having connected thereto a refractory body of incandescing material forming therewith a chamber inclosing the space within the annular electrode on the side on which is mounted the central electrode.

7. An. are lamp according to daim Il, in In Witness Where, We have helmmt which the central electrode has a passage signed our names in the presence of two suhthrough it, and aspirating means for drawscribing Witnesses. ing gases of combustion through such pas- LQUIS MUCLARE 5 save,

D l 'ANDRE GARBARIN 8, An are lamp accordlng to 01mm 4 m which the senil-a1 electrode has a passage GEORGES GAUTER through it, and aspiratng means `for draw- Witnesses: ing gases of Qombustion Athrough such pas,l CHAS. P. PRESSLY,

` 10 sage. REN BARDY.

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