US1788909A - Vapor-arc-lamp-starting apparatus - Google Patents

Description

Jan. 13, 1931. L. J. BUTTOLPH 1,788,909

VAPOR ARC LAMP STARTING APPARATUS Filed July 20. 1925 Patented Jan. 13, i

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a. tube into operation, and to provide improvements in thestructure of the tubes. v It has been common practice to start mercury vapor lamps having one or moreliquid electrodes by tilting the lamp to make and break the metallic connection within the tube. Under certain commercial conditions thetiltr ing of the tube is inconvenient, and I have found it desirable toprovide such lamps witl'r a mechanism for heating one of the liquid I electrodesuntil a conducting circuit has been established. This is a more orless lengthy operation, and I have discoveredthat, by combining with the heating mechanism a mechanism forsupplying a high potential kick across the terminals of the device while the heating mechanism is working'on .one of the liquid electrodes the starting of the arc .tube into operation is facilitated. a

For example, with a quartz arc tube hav ing asolid anodeof tungsten and a cathode of mercury and designed to operate on 600. volts, starting by. the tilting. method is not desirable, due to the fact that the breaking of the heavy arc in the tube causes blackening of the transparent container, and the rush of current is so great as to require complicated auxiliary apparatus to take care of it at the instant of starting. Accordingly, to avoid the deleterious effects of the sudden rush of current through the tube on starting,

and to avoid the use of a multiplicity of relays in the auxiliary mechanism I have provided the tube with a heating mechanism for heating the liquid electrode quickly and by providing mechanism for ap lying a high potential kick across the terminals while the heating mechanism is working I am enabled to start the lamp into operation quickly and at the same time gradually distribute the starting period over a safe interval of time, 10 seconds for example, this interval of startf'comranm or nonoxnn, NEW JERSEY, A COBZPORATIONVOF- N vnon-anc-nmrs'rna rrue ArrAnArus 1925. Serial no. 44,746.-

ing timebeing found suflicient to permit the tube and its operating mechanism of the simple and usual type well known injthe art to take care of the heavy current passing through the quartz arctube.

In the accompanyingdrawingI haveillus; trated my invention in connection with a quartz are tubedesignedto operate ona 600 volt commercial circuit, although it will be understood that the inven't'ion is not limited to this type of tube'or to tubes operating at such high voltage, butitis alsoapplicable' to the relatively low potential mercury arc lamps of commerce.

IIt generally known that a vapor'arc device under certainconditions can be started by a high tension kick provided the temperature of the lamp. lies between certain critical limits. This means that in a mercury quartz lamp the vaporization ofthe mercury and consequent emission of electrons must be begun before the arc can. be started. However, but very little heat is required to be applied to the cold cathode chamber to yaporiz'e the mercury sufiiciently for an arc to be started by a hi h tension kick. 'As a means of heating tie cathode chamber an electric heater is simple to operate and occu'- pies a comparatively small space. I

In the present invention an electric heater is connected. through suitable resistances as hereinafter further described, to the feed lines of the lamp. H i

In this invention a resistance and an inductance are connected in series to the negative terminal of the lamp in the same manner as with other direct current mercury arcs. A mercury switch, or shifter, is connected from a point between the inductance and the negativ'e terminal ofthe lamp in series with a PATENT qoEFllt-c I resistance. This resistance can be used as a heater for the cathodechamber of the lamp. The shifter. is mechanically connected to "an armatureoperating in the inductance in the usual manner., v v V y I In one emb diment of this invention a. part of the resistance in series with the shifter is L in the formfof anelectric heating coil'placed in a suitable manner about thecathode cham her and the rest in the usual'form. In another embodiment the heater is connected in par J allel with the inductance and the arc, with other suitable resistances between the shifter and the heater. V i

The figure in the drawing shows a vertical sectional view of a quartz lamp having a liquid cathodeand aheater therefor, and wiring connections in which the heateriscom" nected in parallel with an inductance and the arc, and with resistance between the shifter andthe heater. o a m 4 -V In the drawing part 1 is a silica tube, 2 is an anode, 3 is a mercury cathode, 4 is a shifter, 5 is an inductance connected to the negative terminal of the lamp and which'is also usedas a solenoid to actuate the shifter 4 through the armature 17, the resistance 12 is connected 'in' series with the' cathode andthe inductance, and is placed between the inductance and the negatlve terminal of the feed in-the manner usual to this type of lamp. The electric heating coil 6 is designed tojsurround the cathode chamber 18 and has one terminalconnected betw'eenfthe inductance '5 and the re sistance 12; its other terminal isconnected to the" positive feed of the lamp through a resistance '10,.and through a switch 8. Between the pointy ofconne'ction of 6 to the ositive feed and-the anode a solenoid 9'i's p aced in the anode "lead. This solenoid 9 isdesi'gned to open switch 8when an arc has been struck in the lamp. One side of the shifter 4 is connected between the cathode and the induc tance 5; its other side is connected through a resistance lland'to a variable connection'on the resistance 10. By having a slidin con nection on the. resistance 10 it 'is possi le to limit the maximum voltage that will'be across the terminals ofthe shifter, thevalue of 10 of course being made such that suitable voltages will be obtained; For.instance,the line volt age might be 500 volts and in such cases it would be desirable to have the shifter operate a part'of resistance 10 where it divides, a

part going through the rest of 10 and through the heater circuit and apart through the resistance 11 and throughthe shifter circuit. These two parts of the current flow together again at a point between the" inductance 5 andthe resistance 12. The solenoid 5 being energized the armature 17 is actuated and the circuit throughtheshi'fter thereby broken.

On the breakin of the connection throu h 4 and therefore t rou h 5 the ma netic. eld about the latter col apses and t ere is induced in it a high "potential. In the meantime current has been flowing through the heating coil 6 and the mercury in the cathode 'chambenhas begun to beheated. So, ifthere has been sufficient mercury vaporized at the time the high voltage vkick is induced in the circuitof 5 an arc willbe struck in the lamp. If thearc is not struck at this time the shifter- 4 through force of gravity swings back into the circuit making position and the connection through 5 is re-established. This intermittent making and breaking of the circuit through 4 willv continue until sufiicient mercury has been vaporized for the striking of an arc in the lamp.-- \Vhen'the'arc is struck the current passing through the positive leads of the lamp will energize solenoid '9 which will operate switch 8 to break the circuit through the shifter and the heater and so leave t-he'nio'ut of operation while the lamp is lighted. After the arc has been struck switch 24 which has'been closed to short circuit half of the resistance 12 is opened to throw all of'said resistance in series with the cathode.

I'claim:

In an electric vapor-*lamp,-in combination,-

a liquid cathodean anode,- feed mains therefor, a solenoid in'the positive lead of the lamp, an electricheater for the cathode connected on one side through a switchto the positive main, said switch being adapted to be opened'by said solenoid when current is flowing through the lamp, an inductance connected on one side to the cathode and on the other through a" resistance to the negative main, a connection from 'a point between said inductance and resistance to theother side of the heater, and afmercury switch connected on one side between the inductance and the cathode andon the other through'a resistance to a sliding connection on a resistance between the electric heater and the switch inthe positive side lead thereof, said mercury switch being mechanically connected to an armature operating in the inductancein the negative lead of thelampQ a p Signed at Hoboken, in the county of Hud son, and State of New Jersey this 3rd day of July, A. D. 1925.

' LEROY J. BUTTOLPH.

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