US2545345A - Enclosed arc starting device - Google Patents

Description

March 13, 1951 H. B. DERl 2,545,345

ENCLOSED ARC STARTING DEVICE Filed May 24, 1950 Inventor Hunt/27' B. 002/ 7n/77 a/jy Gnu-neg starting an enclosed arc.

' connected.

of the invention having all -a-sa1ed enclosure.

Patented Mar. 13, 1951 2.

ENCLOSED Anc STARTING DEVICE Hubert B. Deri, Rye, N. Y., assignor to General" Precision Laboratory Incorporated, a corporation of New York Application May 24, 1950, Serial No. 163,891

This invention pertains to enclosed arc-lighting devices and more particularly to means for starting the arc-discharge in such devices.

This invention is applicable to an'y'type of enclosed are but it is especially useful when applied to that'type of enclosed arc lampfor producing visible light in which light, isproduced principally at the surface of the'cathode electrode. Such an enclosed .arc'is described in the copending patent application Serial No..

83,129 of Hubert B. Deri, filed March 24, 1949. I Enclosed arcs are ordinarily started by the "application of an elevated voltage superimposed upon the arc supply circuit so as to be effective across the arc electrodes. This elevated voltage fmay be either alternating at low or high frequencies, rectified or pulsed direct voltage, or

a momentary inductive surge caused by breaking the current through an inductor. In each of these methods of starting, equipment is required which is bulky and expensive, so that a need has long existed for a better and cheaper method'of starting the arc discharge.

The instant invention provides means for moving one of the electrodes within the arc enclosure and without breaking the hermetic seal thereof, to touch the electrodes together momentarily to start the current flow. Then when the electrodes are separated the arc is drawn between them. Means are also provided for 11 Claims. (o1. tie-"152);-

metal-to'fglass seal, indicated at H.

Referring now to Fig. 1, an embodiment of the invention chosen for purposes of illustrating the invention comprises a gas-tight envelope having a metal cylinder ll closed and sealed at one end by a transparent glass disc I2. To the other end of the metal cylinder I! is sealed one end of a flexible metallic bellows l3, the other 'end of the bellows being sealed to' a metal disc 14. A metal tube [5; drawn to'an enlarged scale for clarity, extends through a central. hole in the disc Hi; the disc and tube It being sealed together mechanically and electrically insulated each-fro the other, by the interposition ofila Themetal tube 16 constitutes part made cathode structure. Thecathode is, per se, comprises a plug of metallic oxides serving as automatically starting the arc, if for any reason 7 the arc should be extinguished. Therefore, one purpose 'of this invention is to provide a simple and inexpensive means for Another purpose is to provide an improved ent closed arc lamp structure in which the t'wo-elecwithout affecting the hermetic'seal A further purpose is to provide improved electrodes are readily movable relative to eachl'o ther :t'rically operated mechanical starting means for an enclosed arc.

A still further purpose is to provide an improved electrical starting means for ane'nclosed arc lamp that automatically restarts the lamp if it becomes extinguished while power remains Abetter understanding of the invention can Figure 2 is a cross section of a modified form moving parts Within 'a light emitter. e 'is fiush with the end IQ of the tube [6. A hole The exposed end 28 of this plug 15 in the tube l6 insures'equal ization of gas "pressure on both ends of the plug I8. The other end 2| of the tube I6, opposite to the cathode end, is utilized as the tubulation for exhausting the envelope and filling it with an inert gas, after which it is pinched off and sealed. A ceramic disc 22 is fixed in the cylinder H to serve as-a guide for the tube [6, fixing it against transverse movement while permitting axial movement. Holes 20 in the disc 22 insure equalization of gas pressure on the two sides of the disc. A stop ring 23 is fixed to the tube l6; and a" compression spring 24 is provided inside the bellows l3, with the respective ends of the spring {such that normally the cathode tube I6 is forced serve as the anode. "ably made of tungsten'or molybdenum. It has 1 an aperture 21 preferably o'fcohi'cal 'shape;"so

-to the left until the'stop ring 23 abuts the ceramic disc guide 22.

-' The gas with which the envelope is filledmay be of any desired inert kind, for example argon or helium, and at any; desired pressure" which will maintain an arc discharge without appreciably combining with the electrode materials during operation of the arc. In this embodiment the pressure is approximately oneatmosphere.

- A metallic disc 26 is fixed in the cylinder I l' to The disc anode 26 is prefer- [that light emitted by". the emitting surface 28 of the emitter-plug [8 can radiate out of the arc lamp through. the transparent disc window [2. The inner edge 29 of the aperture 2'! is in line its with the --inner edge 3l .of the tube. l6, so. that of magnetically permeable material, or at least.

so much of member 33 as encloses the solenoid 32.

A brass member 38 is press-fitted over the tube I6 and is provided with a screw-threaded .stud

39 which engages a threaded bore "ma magthat constinetically permeable extension 4| tutes an armature for the solenoid 32. The solenoid is mounted on anonpermeable cylinder "42 to allow the magnetic effect of the solenoid -to be exerted upon the armature 4|. The material of the lining 42 is chosen to be electrically *nonconductive to obviate the possibility of short- :circuiting the electrodes during any sidemotion of the armature 4|.

A direct current supply of electrical power-is applied at terminals 43 and 44, a stabilizing impedance being interposed in series with either one of the supply terminals as indicated by the TIesistor'46"c0nnected to the negative terminal 43. From the other end of the resistor 46 connection is made to a terminal--41 on the frame v33 of the arc-light device, the terminal 41 being insulated from the casing 33 by a pad of insulating material 48. This terminal 4'| is electrically connected by a conductor 49 extending through the opening 45 to the cathode tube Hi. The

positive supply terminal 1-44 is connected to a zterminal 5| electrically connected to the metallic envelope H of the enclosed arc, which is in thermal and electrical contact with'the anode disc 26. The two terminal conductors 52 and 53 of the solenoid 32 are connected, respectively, to

the two terminals 41 and 5|, putting the solenoid in shunt with the electrodes l8 and 26. v

Before the enclosed arc is put into operation the relative positions of the anode 26 and cathode l8 are as shown in Fig. 1, with the cathode stop 23 pressed against the ceramic guide 22 by the :spring 24, and with the cathode and anode separated. The cathoderand anode are therefore insulated from direct contact with each other but as they are shunted by the solenoid 32. a current path exists from the positive-terminal -44 to terminal 5|, through conductor 53 through the solenoid 32 and conductor52 to terminal 41,-

. and thence through resistor ,46 tothenegative supply terminal 43. When, therefore, a suitable potential is applied to the terminals 43 and 44 the solenoid 32 is energized and moves the plunger .4| to the right to a position nearer the'center of the solenoid. Movement of theiplunger 4| moves the tube l3 against the force of the spring 24 and toward the anode 26, so that the end IQ of the tube It is pressed against the metal anode 26 and makes electrical contact therewith. With electrodes in contact the solenoid 32 is short- -cir cuited and thereby de-energized, permitting the spring 24 to restore the cathode l6 to its former position with its stop 23 pressed against the guide 22. During thisaction, as the cathode tube end --.|9 leaves the anode lip 23, an arc is drawn between these two parts. Experienceshowsthat- The remainder of member 33 may be made of insulating material, if desired. The ends 35 and 3'! also are permeable for the same reason."

4 the cathodic termination of the are, that is, the point on the cathode at which the arc terminates, quickly migrates to the center of the emitterplug |8 of the cathode. It will readily occur to those skilled in the art that instead of the shunt solenoid, a properly designed series solenoid could be substituted. In the latter event, it would be necessary to arrange the springso that the cathode I3 is normally urged toward the anode when no current is flowing. Then when current was flowing the solenoid would retract the cathode to start the arc.

After the arc starts, its impedance being substantially less than that of the solenoid 32, the

short-circuit of the solenoid is effectively continued, so that the solenoid 32 remains de-energized as long as the arc is maintained. If, however, the arc should be extinguished in any manner, while the electrical power supply remains connected to the device, as for instance by a transient pulse of opposing polarity superimposed upon the supply power, the solenoid 32 is then immediately reenergized-and the above described starting action automatically takes place again, restarting the are.

It is obvious that the arc can be started man- -ually by pressing; the projecting end 54 of the armature of plunger 4| until the anode 23 and cathode |8 make contact with each other, then releasing the armature, Whichis-returned to its normal operating position by the spring 24, drawing and starting the arc as before described. In 'such manual operation the solenoid 32 is-not necessary and may be omittedzfrom the device, .and the automatic-restarting will of coursenot occur; Such manual operation can of course be effected not only by pressing with the hand against the plunger 4| but as well by moving the a; second metal cylinder 59, an end disc 6!, and a-cylindrical electrical terminal 52' sealed to the conical aperture 65. Behind this aperture is the cathode structure consisting of a cylindrical bar 66 having a recess 6'! in the forward end filled with a plug of emitting material the outer end of which is flush with the plane of the end'68. This end is so positioned that upon movement of-the icathode to the anode themetal rim of the'end -58 makes metallic contact with the metal anode disc 64. The bar 66 is guided by two guide discs 69 and 1|, made of insulating material, preferably, ceramic material. Both discs have perforations 12 to equalize the gas pressure on the op-- posite sides of the-discs. A magnetically permeable armature disc 16 is fixed to the end 14 ofthe .,-ba.r 66by means of a suitable screw 15 whichalso secures one end of a tension spring 11 to the bar :66. The other end of the spring 1! is seouredby I means of a screw 80 to the electrical terminal 62.

The spring 11 is preferably made of a material I having good electrical conducting properties, such as Phosphor bronze, because it must carry the current through the arc. The barfifi has a-stopo What is claimed is: 1. An enclosed arc c'ollar 18 which normally is pressed against the -guide disc 69 by the tension of the spring 11, holding the anode and cathode apart at aspecific distance.

A coil 19 is positionedupon the cylinder 5.! and an annular flat ring 82 of magnetic material cooperates with the permeable cylinders 8| and 83 to provide a magnetic path of'increased'permeability. The magnetic path is open on the side adjacent the insulating'and nonmagnetic ring 58 to increase the magnetic flux through the armature 1 6.

Electrical power is applied from direct current terminals 84 and 96 through a series stabilizing resistor 8'! to an anode terminal 88 and a oath ode terminal 89, respectively, so that the power to the arc is supplied from the anode terminal 88 "through the annular ilat ring 82 and thecylin'der 51 to the anode disc S t, and from the: cathode terminal 89 through electrical terminal 62 'f'and spring l1 to the cathode bar 66 and the emitting material in the'recess 61. The terminal conductors 9i and 32 are connected to the'terminals 7 =88 and 89 so that the coil 19 is in shunt with the arc electrodes.

' Upon application of electrical power to the ter:

'minalsBA and 86 the coil 19 is energized, attract ing the disc armature l6 and forcing the cathode bar 66 into contact with the anode 64 against the tension of spring Tl. Upon contact, the coil is 'deenergized,

the spring'retracts the cathode bar, and an arc is drawn, the low impedance of the arcin shunt with the coil preventing reactuation "thereof as long as the arc is maintained. If the ,arc should go out while power remains on, the

starting action is automatically repeated to re k start the arc. Y

. The action of this embodiment is thus similar 'to that of the embodiment of Fig. 1, a principal difference being that in Fig. 2 the magnetic arma ture is within the seaed envelope.

It is obvious that numerous other combinations may be made of solenoids of various types with various sealing arrangements that will be equivalents of the described preferred embodiments. As an example, a simple flexible diaphragm may be substituted for the two embodiments shown. Also, it wi l be readily apparent that either electrode may be movable.

lamp comprising, a gastight metallic tubular envelope enclosing an-inert gas atmosphere and having a transparent window sealed in one end of said tubular envelope, a oath ;ode assembly insulatingly sealed to the other end .of said envelope and comprising a metallic tubular support member having a recess facing said window and having a light emissive material filling at least the outer end of said recess, said elongated support member being supported for longitudinal movement within said envelope, a disc shaped metallic anode positioned between said cathode and said window and having its periphery in intimate electrical engagement with the interior surface of said metallic envelope, said disc shaped anode having an aperture in the center thereof for transmission of light therethrough from said cathode, the size of said ,,aperture being substantially the same as that Q'f said recess in the elongated support member of said cathode assembly, and means for moving said cathode assembly toward said anode for momentary contact to strike an are between said elongated support member and said anode.

2. An enclosed arc lamp comprising, a gastight metallic tubular envelope enclosing an inert gas atmosphere, a disc anode fixed in electrical contact within the surface of said envelope and positioned transversely of the axis of said cylinder, a cathode assembly insulatingly sealed to said envelope and comprising a metallic elongated support member having a recess in the end thereof which is within said envelope, said recess having light emissive material filling at least the outer trodes for moving said elongated support member against said anode for momentary contact to strike an arc.

4. In an enclosed arc lamp, a gastight metallic tubular envelope enclosing an inert gas atmosphere and having a transparent window sealed in one end thereof, a disc anode fixed in electrical contact with said envelope and positioned within said envelope adjacent said window, a

cathode assembly insulatingly mounted within said envelope for movement axiallyof said en- -velope, said cathode assembly comprising a metallic elongated tubular member having a recess in the end thereof facing said window, said recess having light emissive material filling at least a the energization of said electrodes for moving said elongated support member toward said anode for a momentary contact to initiate the arc discharge. I

5. An enclosed arc lamp as defined in claim 4 in which said means for moving said elongated member toward said anode is responsive to the initiation of the arc to permit said resilient means to thereafter move said elongated support member of said cathode assembly to a position spaced from said anode to maintain the continuation of said arc.

6. In an enclosed arc lamp, a gastight tubular envelope enclosing an inert gas atmosphere and having a transparentwindow sealed in an end thereof, a cathode assembly insulatingly supported within said envelope and mounted for movement axially of said envelope, said cathode assembly comprising a metallic elongated tubular member having a recess at the end thereof facing said window, said recess having light emissive material therein, a disc shaped metallic anode positioned between the end of said elongated member having said light emissive material and said window, said metallic anode having its periphery in electrical engagement with the interior surface of said metallic envelope and having a central aperture therein for transmission of light therethrough from the light emissive material in said elongated tubular memher, a magnetic armature on the other end oi said elongated tubular member means magnetically associated with said armature to move said elongated tubular member into engagement with said anode to initiate the are.

7. In a combination with the enclosed arc lamp defined in claim. 6, resilient means for normally holding the recessed end of said tubular member at a position spaced from said anode member, -means for applying an energizing potential between said cathode and said anode, and an electromagnet connected in parallel with the electrodes for magnetic association with said armature for moving said elongated member toward said anode for momentary contact with the latter to strike an arc between the electrodes.

.' 8. In an enclosed arc lamp, a gastight metallic tubular envelope enclosing an inert gas atmosphere and having a transparent window sealed in an end thereof, a cathode assembly insulatingly sealed in the other end of said envelope and comprising a metallic elongated support member having a recess at the end facingsaid window said recess having light emissive material filling at least part of said recess said elongated support "member being supported for longitudinal movement within said envelope, a disc-shaped metallic anode positioned between said cathode and said window and having its periphery in intimate electrical engagement with the interior surface of said metallic envelope, an aperture in said anode for transmission of light therethrough from said cathode, an electrical solenoid, an armature op.- erably associated therewith fixed to said elongated support member of said cathode assembly for moving the latter into contact with said anode, and electrical connections connecting said solenoid and said anode and cathode in parallel. 9. In an enclosed arm lamp a gastight metallic tubular envelope enclosing an inert gas atmosphere, said envelope having a transparent window sealed in one end thereof, an expansive metallic bellows sealed to the opposite end of said envelope, a cathode assembly insulatingly sealed to the other end of said metallic bellows,

said cathode assembly comprising a metallic elongated tubular member mounted for movement axially of said envelope and having a recess at the end thereof facing said window, said recess having a light emissive material filling at least a portion thereof, a disc shaped metallic anode positioned between the end of said tubular member andsaid window and adjacent said window, said anode having its periphery in intimate thermal and electrical engagement with the interior surface of said envelope, a central aperture in said anode for transmission of light therethrough from said cathode, a metallic ar mature fixed to the end of said elongated tubular member opposite to the end containing said recess, a solenoid surrounding said armature for coaction therewith and resilient means for normally positioning the recessed end of said tubular member away from said anode and in opposition to the action of said solenoid 10. In an enclosed lamp, a metallic tubular envelope having a transparent wmdow sealed in one end'thereof and a metallic support insulatingly sealed in the other end thereof, a cathode assembly-axiall supported for limited longitudinal movement within said metallic tubular envelope comprising a metallic elongated support member having a recess at one end thereof and having a light emissive material filling at least part of said recess, a disc-shaped metallic anode positioned between said cathode and said window and having'its periphery in intimate thermal and electrical engagement with the interior surface of said metallic envelope, an aperture in said anode for transmission of light from said cathode therethrough, a filling of inert gas in said envelope, a tension spring connecting the'end of said metallic elongated support member opposite said recess to said metallic support within said envelope, a magnetically permeable armature affixed to said metallic elongated support member. and a solenoid positioned to coact with said armature to draw said cathode assembly intocontact with said anode against the re,- tractile force of said tension spring. I

11. An enclosed arm lamp as defined in claim 10 including means for applying an energizing potential across said cathode and anode and means connecting said solenoid in parallel with said electrodes whereby upon initial energization of said solenoid and said electrodes said cathode tubular member will be brought into momentary contact with said anode member to initiate an arc discharge, the contacting of the electrodes and the subsequent arc discharge serv- HUBERT B. DERI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 274,997 Van Ch-oate Apr. 3, 1883 639,786 Spies Dec. 26,1899

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