US1216646A - Method of producing high-frequency oscillatory currents. - Google Patents

Description

I c, AR'MOR. I iIEII-IOI'I 0F PRODUCING HIGH FREQUENCY OSCILLATORY .CURRE' NTS.

APPLICATION FILED OCT. 14. I911.

I'zitented Feb. 20, I917.

9 0/ Vc/oglf Fluid J: t

ATIORNEY WITNESSES:

nuns c. momor menu, PENNSYLVA m1.-

METEOD OI PRODUCING HIGH-FREQUENCY OSCILLATHRY cunnum Specification of Letters Patent.

Applicationllledbctoberli,1911. Serial no. 054,74 1. h

To all whom it mag concern;

Be it known that I, James C. ARMoR, a

citizen of the United States, and a resident of Ingram, in the county of Allegheny and State of Pennsylvania, have-invented a new and useful Improvement'in Methods of Producing High-Frequency Oscillatory Currents, of which the following is a specification.

My invention relates to methods audmeans of producing high frequency oscillatory currents from either direct or alternating our rent sources, and it has particular reference to the production of high-potential waves of high periodicity such as are adapted for use in wireless telegraphy, telephony and similar arts. 7

One object of my invention is toprovide an improved method of producing waves or currents of the above indicated character whichshall be simple to practise and' particularly effective in accomplishing the desired results.

Another object is to eliminateto a great degree the energy losses incident to the methods heretofore employed and to obtain sustained oscillatory waves or currents which will permit of greater transmission distances and more accurate tuning than has been possible in the prior art. By sus tained waves or currents, I refer to waves or currents theoscillations of which are of uniform or equal amplitude.

Still another object is to produce trains or groups of unidirectional intermittent impulses trains of very short time periods.

which shallbe equally spaced in time and of high periodicity, and to employ such impulses to set up sustained trains or. groups of oscillatory currents of the character indicated.

In the past, high. frequency oscillatory currents or waves have been secured and em loyed successfully in wireless work, but difllbulties and limitations have been encountered by reason of 'the fact thatthe waves were not continuously and regularly sustained or were produced in groups or It is well known that when a condenser is discharged acrossa spark gap, the dischar e is oscillatory in character and of extreme y high frequency and, moreover, that the oscillations rapidly decrease in amplitude and are damped out. At the present time, in

wireless work, a rapid succession of such discharges is usually effected and the highfrequenc oscillaticns of rapidly diminishing amp itude just referred to are employed to set up a series of trains or:' ups of waves inthe working circuit. 5?

viously, these groups of we 'es are of the same char- Patented'l eb. 20, 191ml acteras the discharges, that is, of very short I duration and of ripidly diminishing amplitude. Only a fe v of the first oscillations are effective in proc ucing useful results and the energy of remaininiwaves spent or dissipated, in useless wor According to my present invention, I pro pose to greatly increase the number of condenser dischargesp er second and to rupture each discharge at a predetermined time, preferably w I reaches its zero value, although I do not.

en tle first oscillatory wave wish to be limited n this respect. In this way, if a direct our rentsouroe is employed, a succession of equaflly spaced unidirectional intermittent impuls s or half waves of high frequency is obtain ed, which may be employed to setup oicillatory currents in "a WOlklllg circuit cor taining inductance and capacity in proper and predetermined proportions. In case the source of energy employed for charging the condenser is alternating in character, there will a train of unidirectional inte rmittent impulses or waves of equal amplitude and of positive value during one half c cle of the source of energy and a train 0 similar waves of negative value dlllll 1g the other half cycle thereof.

The resulting oscillatory currents or waves will, of course, be sustained andwill be of the same character irrespective of whether the impulsas be positive. or negative, the only effect being that the will be broken up into groups or trains. owever, the duration or len gth of these groups or trains will be very much greater than those secured heretofore :10 far as I am aware, and, by reason theraof, in connection with the sustained character of the oscillations, a material advance in the art of wireless signaling willbe efl'e :ted which will increase transmission distances and the accuracy. of

signaling.

In order toruptun (the discharges between the spark gap terminalsat a predetermined time, I emp 0y a jet or stream of as or fluid of very high velocity which is directed across the gap and serves the purpose of discharge after the first half cycle of the discharge wave is insured. Thus, an oscillatory discharge is revented and a series of like unidirectiona impulses of high -"peri odicity is obtained. Hence, the energy of the remaining discharge oscillations of diminishing amplitude that has'hitherto been dissipated, is conserved, whereby a con'-. siderably better efliciency is secured and greater power is delivered to the working circuit.

Moreover,by rupturing the discharge oscillations after the first half cycle of the discharge wave, the time interva tions is advantageously employed asthe conber of condenser discharges er second may dense'r begins to charge immediately after discharge, so that the periodicity .ornumbe greatly in'creased, depen ing, of course,

so -'Manifestly, various structural devices and.

. circuit constants.

' arrangements .of circuits and apparatus 1 which embody the principle of my invention.

. "fsults secured; 9

-j is-adiagrammatic view-illustrating an are rangemen.t of circuits, and apparatus "which embodies 1n invention... .Fig. 2 is a' view .and'secure, to a greater or, less extent, the

advantages .thereoi, "may be employed in practisingtmyinvention and wlthout at-' f tempting to illustrate all the cations-and arrangements of which my'iinvention' is-suscepti 4 "limited, the "specific: apparatus and arorth but. will permit of In;- the 'accompanying drawings Figure 1 similar to Fig. 1 showing a-shghtly modified arrangement of circuits, Figs. 3 and'4 illustrate other modifications embodying my invention, and Fig. 5 discloses, astill further I modification of my invention.

Referringparticularly to Fig. 1, a source of energy 1 2 is adapted to deliver elec- 'trical energy to a spark gap 3 comprising a plurality of spark electrodes 4,. through.

. circuit conductors 5 and'fi which severally and of inductance 8" connected in series heretofore. occupied by the following useless. oscilla-. .4

upon the capacity of the condenser and other 7 discharges forms, media.

- ber of discharges 'per second.

I Eredetermined time and instant contain a variable section of resistance by a circuit including a variable condenser 9 and an adjustable inductance coil 10.

The source 1-2 may be of direct or alternatingcurrent, as desired, and the condenser inductance coil 10 may be of any construction that is well known to. those skilled in the art. Furthermore, I do not wish to be restricted as to the specific structure of the electrodes 4, although I prefer to employ very thin disks of a suitable metal and to provide means whereby said electrodes may be rotated at a considerable speed. 1

In proximity to the coiiperating electrodes 4, is ocated a nozzle 11 stream of gas or fluid of very high velocity is discharged, said str'eam being'directe'd across the discharge path between the electrodes 4 in order to be eflective in posi tively rupturing the discharge to be hereinafter set forth.

through which a f in a manner;

It is Well known that if a condenserbe connected in shuntto a suitable spark gap" and be char d from a constantpotential source, that t e spark gap will always break down at the same voltage and the discharges will occur at regular intervals of time, de-

pendin upon the capacity of the condenser andot er circuit constants. This is true only for a. comparatively small number of per second under the usual con- 1 ditions, above which a continuous arc is maintained. However, according to my in:

vention, by providing a h' h-velocity fluid w rupture t e discharges-vat jet to positivel ion a predetermine time and,b suitably choos i thecapacity of the con enser 9, and the le, I will describe several, va u typical embodiments thereof, as illustrativev zoftheiapparatuswhich I now consider t'o es of the resistance sections 7, any 'de- I be obtained acrossthe' spark gapa. .b -be w as P d the desired 1 1,1 sultsg,. '-It be understood, however, i-that broadly considered, my invention is not 1-;' range'ments set p jgmany yariations; which donot materially- TI contemplate the "production of oscillatoril currents or waves having a frequency as Y 'gh as twohundred thousand oscillations or second although currents of ess riodicity may'fbe obtained, 'andfI ter "or" there ore e'mploy'a condenser 9- oi very low capacity inorderto secure the Furthermo'rq -it, is well known a condenser dischargesacrosska sp, 1;1ew I resistance path is established betweenthe spark electrodes which becomesgconducting meansof the jet of gas or fluid 11 I. mp s nc ease-the length of this low -re istance.

'in character after the i i fi flt path within a given period to h gn that theroscillato'ry discharge wave will ruptured after the first half cycle or 'when' it reaches its'fim zero value.

More properly I eliminate any cycle at all; -and Iopen the circuit com lately-at ajy p n the rst discharge by the mechanical motion of the ,medium tween the electrodes. The

action is not analogous to cooling, in which a conducting path gradually disappears by becoming less and less conducting.

To explain the matter further itmageebe t,v has pointed-out that inf ithe prior arti understood, both as to a so-called spark gap, and as to an arc, that the discharge was 0s cillatory. That is, the volta e on oneelec trode is built up until it is an cient to break down the intervening insulating medium,

whereupon a dischar e occurs which has the immediate effect of eating the medium or creating a metal vapor which becomes a con- I ducting path, and acts as a conductor for a reflex passage of electricity in-the other direction. The action of the discharge is like the motion of a pendulum, every movement in one direction being followed by a. reflex movement in the other direction by reason of the overcharge of the opposite electrode, and I the electric resiliency of the circuit contalm ing inductance. In the so-called'quench gap systems in theprior art various cooling deviceshave been employed to quicken the de-' ualities of passage at all, and cooling has nothing to do with the action whatever. The discharge occurs when the potential or electric pressure has been built up to a de locity of the medium ls'so great that when n the discharge has passed once, the path itself has disappeared, beinlg elongated to such de-" gree that it is of big new intervening medium inter osed in the I f interim.

natin'g currenti v y a I omplish this result, the ve-f locity ofthestream must necessarily'bear a er resistance than the An vapor created y" the discharge has eco longer accessibleasa path for any reflex discharge. The result is a'i regulated series of." s in one direction only. these hfolfl refer trilwhat 1s propery ca e ig uency osci ation. as distinguished L the. ordinary. alterdead-beat jdischar In order to I l more or-less definite relation to the width of the gap terminals, the number of discharges "1 cuit. In practice, n 1t will'be found expedie- 2 per second, the sparking distance and. the

1. natural oscillation period of the shunt cirtio us'to determine the proper velocity by exvelocity is related to the elements referred to, I will present ,a rough calculation of the r illustrative.

e original.

I which allows. theovercoming of the resistance of a moving path of intervening medium, buttheveme dissipated, and {is no y same, it being understood thatthevalues:

assumed and t no result jsecured are only g i For example: Let it beassumed maths] resistance sectio: s 7 and the capacity or condenser 9 be so adjusted that'200,000 discharges per .se cond are obtained, which means that the time interval for a single charge'and dischargeis of a second.

' Let it be further assum for best operating ,conditions and results, that the actual time V :of a single disc]: argeto the total time intervol of a single charge and discharge should be in the who oi 1 to 3.

of course, will vary considerably, dependent,

experi nents. Ifithen, the time of discharge: itself is to ruptured after the first "ha i. required per haTf cyclejs This assumed-ratio,

upon conditioni, andlmay be bestJdeteri mined by p a discharge is to'be. a; third of the total time interval ofcharge-anddischarge, and if the "ycle, it ,is evident that thetime a .ofa's'ec 0nd. "In order-[so meet this conditon, itis n I merely necessary to adjust the shuntcircuit to the proper n1 ltural oscillation period-by -means ofa'djust ments of theinductance 10 with respect to the capacity oi' the condenser 9; J

, l If now the sp lr'kinfg distance" between the electrodes 4 be a! sumed te be fl' of an inch, -it is evident'tha; if the lowqresistance, path established between said',-. electrodes bef drawn out toa length that is roughly some '.multiple of thesparking distance .iinthe of di'schsr e, a r'u tarefo f'the dis- "charge will be e ected a a cycle, or at the z are pointof-the wave. Ob-

r the first half vlously, the prop er multiple requires experimental determir ation 'but, for v the present urpose, it will beassumed that the value is me a The required velocity of thestream in feet per second should thenf'be mately equal to the product 1 4 l by approxi or approximate y 1000 feet per second.

Such a velocity is ,not impracticable as, with certain gases-o1 fluids, hydrogen for instance, velocities -of 5000 feet per second may readily be secured.

It should be borne mindthat calculations Of ,"thlS..Ch tI'ECte I' il.r8 not sufliciently accurate for practipal purposes but serve mereI togive a approximationgf the refor the assumed condit iiiiis and values, a stream of greater than thcalculated velocity, would accomplisl tgfthe desired result.

. Assuming theni'that the velocity of the I r stream is of the propervalue and that a diperlment, but, in order to show that this rect current 1 soul cc :of energy, is employed,"

e, quire velocity and to show that it is. re- .;=';fl lated to the elements specified. Obviously,

amplitude are secured and that these impulses are equally spaced in time and correspond to a frequency of 200,000 per second. These high frequency impulses are diverted into the shunt circuit containing the condenser 9 and the inductance coil 10 and are prevented from being reflected upon the source 12 by means of the inductances 8 which tend to choke back the high-frequency waves and to maintain constant circuit conditions.

If an alternating current source be used, a group or train of unidirectional intermittent impulses of a positive value will be secured corresponding to the first half cycle of the alternating source, while similar impulses of an e ualand negative value will be established for the last half cycle of the source.

In some cases, better results may be secured by the employment of an auxiliary condenser 12 which is connected in shunt to the spark gap 3, as shown in Fig. 2, and, in such'an event, the relative capacities of the condensers 9 and 12 and the amount of inductance 10 should be determined experimentally.

Reference may now be had to Fig. 3 which shows an arrangement of circuits similarly to that of Fig. 1 and, in addition, a closed working circuit which is inductively associated with the inductance coil 10 and contains a variable condenser 13 and an adjustable inductance coil 14. The coil 15 constitutes a secondary member of a transformin device 16, the primary member of whic isvthe inductance coil 10.

With this arrangement of connections and apparatus, it is evident that if a series of umdirectional intermittent impulses of equal amplitude and of a high frequency be established through the shunt circuit containing the primary inductance coil 10 and the condenser '9, a series of sustained oscillatory currents or waves of a corresponding periodicity will be set up in the working circuit, provided the relative proportions of inductanceand capacity therein be adjusted for the proper natural oscillation period. This workin circuit is termed resonant to the particular frequency, although it is usually not strictly so. I In employing the term resonant in this connection, I mean that the relative proportions of inductance and capacity in the circuit are such as to correspond to thenatural time period of the current of the desired frequency.

In case the source 12 be alternating in character, the oscillatory currents or waves produced in the working circuit will occur in groups or trains by reason of the changes in value of the impulses produced in the shunt circuit. Moreover, if the working circuit be tuned or the capacity and inductance be mutuallyadjusted for the particular frequenc of the intermittent impulses, it will be ound that the oscillatory currents developed therein will exert a tendency toward smoothing out any slight irregularities in the periodicity of the impulses and will keep them in step.

In Fig. 4 a somewhat modified arrangement is shown which differs from that shown in Fig. 3 in that the conductor 6 is connected to the shunt circuit at a point 17 between the inductance 10 and the main condenser 9, which is shunted by an auxiliary condenser 12. With this arrangement, the inductance 10 is not efl'ective during periods of charge and the energy is delivered directly to the condensers 9 and 12, whereas, I

during the period of discharge, it is included in the circuit, and is traversed by the rapid succession of intermittent impulses.

Referring now to Fig. 5, which is a perspective view of a pair of cooperating rotating electrodes which may, in some cases, .be employed to advantage in practising my invention, the spark ap 3 embodies a plurality of thin disk e ectrodes 4 which are adapted to be rotated from a driving shaft 18 by means of suitable pulle s 19, 20 and 21 and belts 22 and 23 in a wel known manner. Shafts 24 and 25 to which the electrodes 4 are respectively attached, are rotatably supported in bearing members 26 and 27 and are respectively provided with slip rings 28 and 29 cooperating contact fingers 30 and 31 by means of which electrical connecgions with conductors 32 and 33 are ma e..

When employed in connection with a nozzle, as hereinbefore set forth, the electrodes 4 should be extremely thin and should be rotated at moderate speeds in the manner shown in Fig. 5. However, it may be found advisable to dispense with the nozzle 11 and rotate the electrodes 4 in opposite directions at very high predetermined speeds in a suitable medium whereby the high velocity stream or 'et of fluid, hereinbefore referred to, may e. produced by-the electrodes themselves, it being understood that if sufficient peripheral speed be secured a portion of the medium adjacent to the edges of the electrodes will be set in motion and carried around therewith. In this way, the re uired high velocity jet or stream is pro uced,

- IL/I oscillating current by the influence of said high frequency intermittent discharges; substantially as described.

2. The method of producing regularly spaced intermittent non-oscillatory electric currents of high frequency which comprises passing a current through a circuit across a gap etween two electrodes and positively interrupting said gap by mechanically moving an insu atin medium between the electrodes, with su cient rapidity to make the electric discharges dead-beat, or uni-directional.

5" tory high frequency intermittent currents gap, subjecting the gap 3. The method of producing non-oscillaby passing a current through a circuit containing a gap causing discharges across the to the effect of a movlng insulating medrum having such velocity as 'to-prevent oscillation and regulating the frequency of discharge in art by varying the velocity of the medium etween the electrodes.

4. The method of producing high frequency oscillatory currents by induction rom another circuit, by exciting that other circuit with direct current adapted to jum a gap therein, subjecting said gap to the e fect of an insulating mediu 'moving therethrough at much speed as to prevent oscillation, and re gulatmg the frequency of such intermittent discharges in part by var ing the veloci as describe 5. The method of producing hi h frerom anothi r circuit by creatin high frequency oscillatory currents by in uction of the medium, substantially w charges in that other circuit, includin the step of in part governing the rate 0 discharge between .two electrodes in said primary circui1 by subjecting them to the influence of a moving stream of insulatin medium, where by the path of discharge is always -longe1 than the direct distance be- ,--tween the e11 ctrodes and will de nd for its len h upon the velocity of sai insulating me ium the rethrough. I In testimony whereof, I' have hereunto subscribed my name this 12th day of Oct.,

JAS. C. ARMOR. Witnesses:

D. H. MACE,

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