US1904995A - Method and apparatus for producing light - Google Patents

Description

A'pfil 25,-1933. E. F. NORTHRUP' METHOD AND APPARATUS FOR PRODUCING LIGHT Filed June 11, 19:0

Patented A r. 25,1933

- UNITED STATES EDWIN FITCH NORTHRUP, OF PRINCETOIhl', NEW JERSEY METHOD AND APPARATUS FOR PRODUGING l My invention relates to methods and apparatus for producing light.

lhe principal purpose of'my invention is to combine the advantages of an electric incandescent lamp and of a glow lamp.

5 resonating the circuit to'secure maximum effectiveness and using high frequency to reduce the capacity required for a given reactance.

quency current tor the purpose of producing lightunder conditions of desirable economy.

A further 'purpose is to obtain light on a commercial scale by the bombardment of an electron em ssion from a hot body against.

the molecules of gases and solids A further purpose is to lighta' lamp from a circuit in which the conditions of series resonance obtain.

A further purpose is to produce light by maintaining a high potential difference between two or more hot bodies. Y

A further purpose is to connect a plurality of heated elements contained within a closed lamp to a source of alternating'eurrent.

A further purpose is to. maintain a potential difierence from an alternating. source be-' tween a plurality of electrically heated elements surrounded by .a'v'acuum or by a spe- 40 cial gaseous atmosphere. p I

A further purpose is to electrically heat a plurality of incandescent lamp filaments contained within a lamp, and to add to the lightgiving qualities of the filaments the glow produced by the luminescence of gases contained in the lamp, due to electron emission from thefilaments. 1

A further purpose is toconstruct combined incandescent "and glow lamps which may be connected to a- .common current source in series or in parallel.

A further purpose is to utilize high fre- Figure 3 diagrammatically illustrates a 75 Application filed June 11, 1980. Serial No. 460,531.

Further purposes will appear in the specification and in the claims.

My invention relates both to the methods or processes involved and to structure by whtich the methods or processes are carried ou Y I have preferred to illustrate my invention by a'few embodiments only of the same general form, selecting embodiments which are effective and fully operative but which have been selected primarily because of their suitabllity for illustration of the principles involved.

In the drawing like numerals refer to like parts throughout. f

F igure 1 is a diagrammatic representation of lamps A and B embodying my invention connected in parallel to a common current source.

Figure 2 diagrannnatically indicates the connection of a plurality of my lamps in series, E, the series being itself in-parallel with a lamp C and a lamp D.

conventional seriescircuit containing resistance, inductance, and capacity.

' Figure 4: 1sa vector diagram for the circuit of Figure '3, assuming arbitrary values for the resistance, inductance and capacity. J

Flgure 5 is' a vector diagram for the circuit of Figure 3 under the conditions of series resonance. Figure 6 shows a lamp embodying my invention in which the electron-emitting bodies 5 are heated by separate current sources, and a voltage drop is maintained between them by series resonance in another circuit.

Thedevelopment of the audion tube has served to familiarize theart with the phenomenon of electron emission from a hot body,

particularly when that body is connected to the negative side ofa direct current Source, and the positive line from the source is connected to'an element maintained adjacent to the hot body and within the tube. I propose to apply this phenomenon to increase greatly the light-giving effectiveness of an electric lamp.

I ope me at my lamp from an alternating curanother, because this would prevent the mainf rent source, and am thus able to employ a plurality of hot bodies within the electric lamp. Considering for the present only a. single phase source, I will use two hot bodies within the lamp, one connected to each side of the current source, so that the direction of electron flow from or toward either body will reverse with the reversals of the current.

It would of course be possible to maintain the temperature of the hot bodies by connection to current sources local to each of them, as is done in the familiar A battery circuit of the audion tube. This would, however, be

complicated, expensive, and ineflicient, and therefore I prefer to maintain the temper ature of the hot bodies by RP heating from the line current. I do not pass the line current directly from one of the hot bodies to tenance of a high voltage drop between them,

such as is essential to the production of light" from electron bombardment.

7 While I intend to maintain a considerable voltage between the heated bodies in the lamp, I plan to avoid distributing high voltage current in a building in which the lamp may be employed.

I find-that it is possible to secure a high voltage drop across the heated bodies within and E with the assumed current value I.

It is there seen-that the current lags the voltage E by the angle a, so that the power factor regulation will be poor. I

If the circuit be resonated, however-that is, if the inductive reactance and the capacitative reactance be made equalthe power factor will become. unity. Obviously, under this condition, the voltage drop E across the capacity will equal the voltage dropE across the inductance, and the line voltage will equal the voltage drop E across the resistance, merely. This is apparent from Figure 5.

Thus a very high voltage drop may be maintained across the inductance, although the line voltage is low.

With the ,usual line frequency, such as cycles for example, the size of the inductance coil or of the condenser required to maintain resonance would be prohibitive from a commercial standpoint. However, at high frequency, the circuit may be resonated by the use of very little inductance for a given capacity. This may be understood by expressing the frequency 7 under the conditions of resonance in terms of the coeflicient of selfinduction L and the capacity C. For. resonance the inductive reactance X must equal the capacitative reactance X Now (Gray, Principles and Practice of Electrical Engineering, McGraw Hill Company.

(3d ed. 1924) 213, 227). During resonance For any given capacity, the size of the inductance coil requiredto resonate the circuit is inversely proportional to the square of the requency.

Thus byfar the greatest advantage from my invention is to be derived by 0 eration on high frequency current preferab y at about 1000 cycles. A considerable by-product advantage will be obtained because my lamps may operate from circuits designed for high frequency induction furnace operation or for other/uses.

Referring now to Figure 1, I there show a source of alternating current 10 supplying current to lines 11 and 12 at any suitable voltage, for example, at 220 volts. In lamp A,

the lamp body 13, constructed of glass or any other suitable transparent or translucent material, contains the hot electron-emitting bodies 14 and 15, attached'to terminals 16,

17 ,1 18 and 19 extending through theglass wa l. v

The lines 19 and 20, extending from OPPO'.

site sides of the supply mains 11 and 12, are connected respectively. to one side of the reactances 21 and 22, here shown as condensers.

The other sides of the reactances 21 and 22 are connected to the terminals 16 and 18 re spectively. The terminals 17 .and 19 at the other ends of the filaments are attached to the respective ends of the opposite reactance 23. in this case an inductance coil.

'- .The bulb 13 may contain air highly evacuated. Or else, if desired, the air initially present in the bulb may be replaced by a suitable gas, which may be evacuated. As an alternative I may prefer to fill the bulb with an inert gas such'as nitrogen, argon, etc., at normal atmospheric or low pressure. It is well known that the color of the light emitted, or, more strictly, the wave lengths of the most prominent radiations within the luminous range, depends .to a considerable extent upon the character of the substance which is made to glow. I may vtherefore ob tain lights of various colors and characteristics by proper choice of the gaseous atmosphere surrounding the electron-emitting odies.

to that which may be produced in gases. I

may cause the electron flow to impinge upon solid bodies adj acent'to the electron-emitting bodies, more particularly the walls of the tube. By use of special glass, or of other similar substances, for my tube wall, I may produce fluorescence in the wall under the electron bombardment, and'employ this'as an additional light-giving means.

' As seen from the vector diagram of Figure a high alternating potential difference ex ists between thev filaments 14 and 15.

The

filaments are maintained at an incandescent temperature by current flowing through them, and will produce light as in the case of any incandescent lamp filament. In addition to this the electron flow alternately from one filament to the other will bombard the molecules of environmental gas and cause them to produce light. And the bombardment against the tube walls, or against any solid body exposed within the tube, may cause further luminescence.

The spacing of. the electron-emitting bodies, 'whether'close or far apart, as well as their shape, will depend upon the size of the lamp, the direction in which the light is to be directed, the voltage and frequency at which the lamp is to operate, the disposition of the supporting structure within the lamp, and the character of the gaseous atmosphere about the hot bodies, among other things. I therefore intend the disposition of the filaments in lamp A'of Figure 1 to be purely diagrammatic.. I of course do not wish to suggest that the distance between thefilaments would be the same as that shown when my invention is embodied in an actual lamp of any size.

I intend to indicate that the electron-emitting body may be of any shape or form, whether a rod, sheet, wire, plate or grid, or any other suitable structure. In lamp I show thebodies disposed in the form of grids 1 L and 15', which may be pressed from sheet material, or bent from rod, tubing, or wire. In lamp C Ishow concentric-helical filaments 1 F and 15 disposed one about the other to permit the inclusion of considerable filament length within a small tube inclose proximity to another filament similarly placed. Other arrangements of the electronemitting bodies will doubtless suggest themselves to persons skilled in the art, and it is my intention to claim all such as may embody my invention. a In Figure 6 I illustrate a form which I do'not consider desirable, but which serves to make plain that my electron-emitting bodies maybe maintained hot from separate that positive reactance (inductance 21 current sources, as 10 and 10 while the potential difference between them is due to'series resonance in a circuit consisting of the is opposite in character and proper in amount to produce series resonance. Thus in lamps A and B of Figure 1 and lamp C of Figure 2, the reactance between the electron-emitting bodies is positive (inductance 23) so that elsewhere in the circuit negative reactance ( ca acity 21 and 22 or 21) must be provided. 11 the other hand, in lamp D of Figure 2 the reactance between the electronemitting bodies is negative (capacity23 so and 22 must be supplied elsewhere.

Thus it will be evident that the reactance between the electron-emitting bodies may be either negative or positive, but that in any case opposite reactance must be placed elsewhere in the circuit to resonate it.

Provided reactance is included in the lamp circuit between the electron-emitting bodies In lamp B I show only one condenser 21, connected in series between the current source and the source of current, it is immaterial 9 how it is disposed. In lamp A I show myv reactance in the 'form of two condensers 21 and 22, in series with the lamp between the current source and the respective filaments. Q

and one of the filaments. From an electrical standpoint either of these forms is permissible, but I prefer the symmetrical disposition of the reactance as shown in lamp A and throughout Figure 2. The reactance may be made up of several units, in series or in parallel, instead of. being a single inductance or condenser.

In Figure 1 I show two of my lamps con nected in; parallel to the same supply source.

In Figure 2 I show four lamps E connectedv invention according to the principles here disclosed, applying the well known circuits for currents of any. given phase.

It will be evident that by using current at high frequency I obtain the advantages of working under unity power factor, of obtaining greater eificiency and of distributing current much more-simply and cheaply than would be possible at low frequency. In addition, I obtain the further advantages over the ordinary incandescent lamp that the size of my lamp is not restricted by the convenient filament size, for the entire lamp will glow and serve as a source of light instead of merely a relatively small filament.

In manufacturing .my lamp it would doubtless be possible to construct. the inductance coil and the capacities as part of the lamp body or of the lamp mounting, but I do not propose to restrict my invention to any specific lamp structure. I rather desire to protect any structure which involves the principles disclosed.

In view of my lnventlon and disclosure variations and modifications to meet individual whim or particular need will doubtless. become evident to others skilled in the art, to obtain part or all of the benefits of my invention without copying the structure shdwn, and I, therefore, claim all such in so far as they fall within the reasonable spirit and scope of my invention.

3. The method of electric lighting which consists in electrically heating a plurality of elements within a lamp, maintaining a reactive potential difference between the elements and producing series resonanpe of theheating current path.

4. The method of electric lighting which consists in maintaining a plurality of separate incandescent current'paths in seriesin a closed system containing a gas at-substantially different potentials of high frequency by reactive voltage drop, across the current paths and producing luminescence by cur rent discharge through said gas due to the potential difl'erence between said current aths. j p 5. The method of electric lighting which consists in resonating a circuit including a lurality of hot current paths, in maintain- 1n the hot current paths in a closed system at su stantially different potentials and in pro ducing luminescence from electron emission due to the potential difference.

6. In an electric lamp, a source of current supply, a lamp body containing a plurality of elements adapted to be heated to incanrespective elements, reactance in the connections, and opposite reactance connected from one element to another.

7. Inan electric lamp, a source of current supply, a lamp body containing a plurality of filaments each having two contacts, connections from the .source to one contact of each filament, reactance in one of the connections and connections, including opposite reactance, joining the other contacts of the filaments.

8. In an electric lamp, a source of current supply, a lamp body containing a plurality of filaments each having two contacts, connections from the source to one contact of each filament, reactance in the connections.

connections from the further current source to one contact of each filament, reactance in the circuit, and opposite reactance between mg each filament, a further current source,

.descence, connections from" the source to the y the other contacts of the filaments appro I priate to produce series resonance in the circult at the frequency of the further source.

10. In electric lighting, a source of ourrent supply, a lamp body containing two I filaments, reactance connected between the filaments, connections from each filament. to the current source and opposite reactance between the lamp and the source.

11. In an'electric lighting system, a source of current supply, a plurality of lamps each containing aplurality of filaments, connections from the source to one end of each filament in one lamp iljicluding reactance between the source and the lamp, connections from the other ends of the filaments of that lamp to the respective ends of the filaments of other lamps so as to place the filaments electrically in series, and opposite reactance 'lbetween the ends of the filaments of the last amp. v

12. In electric lighting, a plurality. of

lamps each containing more than one filament, reactance connected at its respective ends to one end of each filament, a source of current supply, and connections, including opposite reactance, to the supply from the other end of each filament placing the lamps electrically in parallel.

13. The. method of producing light, which consists in setting up series resonance in a current path including reactance and in impressing the reactive voltage drop across the environmental gas in a closed system.

14. The method of producing li ht, using electrodes in a closed system, whic consists in heating the electrodes, in setting up series resonance in a current path including reactance and in impressing the reactive voltage drop between the electrodes. I

15. The method of producing a. discharge across a tube from a source at a voltage too low to send current across the tube, which consists in producin series resonance and in connecting the tube ietween points of maximum difference in displacement of voltage with respect to curren 16. The method of producing light, using a tube having elements, which consists in passing alternating current successively through a reactance, to a hot-element of a tube, through an opposite reactance and to another element of the tube.

I 17. In ane1ectric circuit, a tube having elements, asource of alternating current, circuit connections from the source to'the elements and means for producing series resonance in the circuitand for producing a reactive otential drop between the elements.

18. 11 an electric circuit, a tube having elements, means for heating an element, a source of alternating current, circuit connections from the source to the elements and means 80 for producing series resonancein the circuit and for producing a reactive potential drop between the elements.

' 19. An electric circuit including in series.

in the ordernamed, a source of alternating current at high frequency, a reactance, an element of a tube, an opposite reactance and another element of the tube.

EDWIN FITCH NORTHRUP.

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