US2881335A - Generation of electrical fields - Google Patents

Description

B. VONNEGUT April 7, 1959 GENERATION OF' ELECTRICAL FIELDS Filed May l5. 1956 IN1/EN TOR. 35e/wma l/o/wveauf BY OMI Arron/5V United States Patent O GENERATION F ELECTRICAL FIELDS Bernard Vonnegut, North Scituate, Mass., assignor to Arthur D. Little, Inc., Cambridge, Mass., a corporation of Massachusetts Application May 15, 1956, Serial No. 584,943

2 Claims. (Cl. 310-5) This invention relates to the conversion of mechanical energy into electrical energy and more particularly to a regenerative system for charging bodies or clouds.

It is desirable in many processes to be able to control the charge on a stream or body of discrete particles such as ne liquid droplets, aerosols, dust particles, etc. It may further be desirable to concentrate such particles bearing like charges into isolated volumes and thus to build up an electrostatic iield of high intensity between such isolated volumes of charge concentrations. For example, the establishment of two isolated volumes of charged particles, those in one volume being substantially all positive and those in the other volume being substantially all negative, offers the possibility of creating ahigh potential difference between such volumes of charged particles. Likewise depositing similar charges on a cloud or stream of aerosols or dust particles, for example, oters the possibility of directing the ilow of such particles by means of electrical attraction to a target.

Various methods are known for charging particles or bodies, but they commonly'involve the use of auxiliary power equipment or an outside source of electricity. Hence, these systems are generally not available for use where electrical power is not available. i

It is therefore an object of this invention to provide a simple method for converting mechanical energy into electrical potential energy. It is another object to provide a means for regeneratively charging particles and bodies and to accumulate them in isolated volumes of like charges, thus creating an electrostatic field between the isolated volumes of accumulated charged particles. It is another object to provide a simple method for generating high voltages at locations where electrical energy or auxiliary power is not available. An additional object is to provide a simple method for generating high D.C. voltages within a very short period of time. It is a further object to provide a method whereby the aqueous particles of cumulus clouds may be charged rapidly with a total charge suicient to induce lightning and a subsequent rain storm.

The method for regeneratively charging particles according to this invention comprises directing lirst and second uid streams of discrete particles past a positively charged electrode and a negatively charged electrode, respectively. The particles of the Streams assume charges opposite in sign from the respective electrodes which they have passed and they carry and deposit these charges respectively in first and second isolated volumes in which charges are to be accumulated. The positive and negative charging electrodes may be identical with the volumes of accumulated negative and positive charges, respectively. Thus, there is provided in accordance with the teaching of this invention a method for amassing electrical charges which is regenerative in nature. The process of this invention will be presented in more detail in the following discussion and with reference to the accompanying drawings in which:

v2,881,335 Patented Apr. 7, 1959 Fig. 1 is a perspective view of an apparatus suitable for developing high voltages without the application of any outside energy source except that which is required to create two streams of liquid droplets;

Fig. 2 is an electrometer record for a generating device such as shown in Fig. 1 and constructed according to this invention; and

Fig. 3 illustrates the application of a partially regeneratlve system to the control of charges in clouds of partic es.

In Fig. 1 there is illustrated a simple and effective means for generating very high voltages in a short time. The apparatus comprises two electrodes 10 and 11 and two sources 12 and 13 of streams of liquid droplets, the sources being grounded at 14 and 15, respectively. Inasmuch as an object such as an electrode 10 or 11 always has a small charge on it, the system requires no priming. Assume, for example, that electrode 10 of Fig. 1 has a small residual positive charge on it. A stream of water 16 (for example) is directed from source 12 past electrode 10 onto electrode 11. Because of the positive charge on electrode 10 the water stream which comes within the field of inuence of electrode 10 will assume a negative charge before leaving source 12. Because of surface tension the streamwill be broken down into droplets 16a which carry on them the charge induced in the stream 16. These negative charges will then be deposited on electrode 11 as the droplets 16a strike it. Likewise, water droplets 17a are formed by breaking oil from stream 17, which in turn arises from source 13, and is charged by electrode 11. Droplets 17a carry induced positive charges which they deposit on electrode 10, the positive charges having been induced by the iniluence of negative electrode 11. 'I'he charges on electrodes 10 and 11 are led oil by means of leads 18 and 19, respectively, to furnish a supply of high-voltage, D.C. current. Although one stream may be started before the other one, this is not necessary to the eilicient operation of the process. An alternative to grounding liquid sources 12 and 13 would be to connect these two sources, thus completing a circuit in the system.

From the above description, it will readily be seen that the process of this invention is a regenerative one and that once the streams are activated the build-up of electrical charges on both electrodes is very rapid; the greater the positive charge on electrode 10, for example, the more rapid is the build-up of negative charges on electrode 11, and likewise the greater the amount of positive charge build-up on electrode 10. Tlie rate of charge build-up is in fact exponential.

The quantity of charges which can be built up on electrodes 10 and 11 depends, of course, upon the design of the electrode and upon the force with which droplets 16 and 17 are expelled from the respective sources 12 and 13. Thus, a situation may be reached where the mechanical energy of the liquid droplets is less than the energy required to cause them to strike the electrode. Thereafter, the droplets will be repelled and the charges on electrodes 10 and 11 will level off. Thus, the kinetic energy contained within each drop as it breaks away from the stream must be equal to or greater than the mechanical work which is required to carry that drop against the electrode.

In Fig. 2 there is reproduced an actual electrometer record which shows charge build-up in a device such as that illustrated in Fig. l. As indicated in the record, the charge build-up is exponential and the attening of is caused by the limits of the electrometer rather than by limits of the generator. A negative indicates an electrode was primed to go negative.

In Fig. 3 there is shown a modification of the process of this invention as it may be applied to controlling the charges .on 'partielles making up clouds. Thus, cloud plumes `and 21.013 Eig. 3 arecomparable .to electrodes 10 and 11 in Fig. 1 and stream sources 22 and 23 to stream sources 12 and 13, respectively, of Fig. 1. Some additional energy sources 4o rpriming charges are prefer ably used in-this modification .of my invention.

This additional .energy may be in thezorm ;of;a point discharge, such asobtained by corona discharge, or Ain the form of a radiation source. In thecase of :a pointidischarge typeof arrangement, s uch as represented byfpoints 24 and 25 of Fig. 3, an extremely high'voltagewould be required vin order to ionize the ysurrounding air constituents and particles contained in the :air in order to enable them to deposit their charges on the cloud particles 26 and 27. For :this reason, ;i t; is;nref erable1to prime one ofthe dischargepoints :by :using a second electrode, such as, for example, ,plate 3010 cause point 25 vto go into point discharge. Once sufficient chargedcloud particles 26 build up in cloud ,20, 1priming may be discontinued.

The 4alternate method of furnishing additional energy, i.e., the use of agradiation source inplace of -pointdischarges 24 and 25rwill;no trequire prirningzbecausegionization of the air and particles contanedfin the air ismore readily achieved.

The discharge Vpoints 24 and 2,5;1nay`begrounded1at28 and 29, respectively, as illustrated inLFg. 3, ,ortheymay be connected as pointed out Wfor the arrangement illus- `tratedin Fig. l.

The process may b e `further explained iwith reference to Fig. 2. To begin, a voltage is applied ite Plate 30 which Acreates an electric v tield and causes point discharge from point 25. vA positive potential applied to plate 30 will cause `point 4Z5 to gire -`coronasulischarae- .T Ihesfast .negative ions :produced vin the v.air by reason of .discharge by peint 25 are then drawn byzplate 30 ,through the smoke or cloud stream as itemergesfromisource 23, where ,these ions become attached :to :the cloud particles. Ihe :movement of the air then carries these lcharged vcloud particles, such as 27, out into the plume 21 naway from plate 30. The accumulation of Inegative' cliargcsin the ,top of cloud plume 21 causes jpoint 24 to give fpoint discharge and to produce a vstream of fastmoving positive ions which become attached to the cloudparticles in plume 2 0 as they emerge in the cloud streamfrom .source 22. Ille accumulation of positive charges in cloud plume 20 then becomes suicient to maintain point :discharge from point v25. When this occurs :the arrangement is selfexciting and high voltage needno longer be applied to plate 30.

In the :case of the .cloud 'plumes .of Fig-3, :the ne'cloud droplets or particles :are so small `that their movement Vis determined by the movement fof -the .environmental air more than bythe electric field asfin the arrangement illustrated in Fig. t1. Thus, the force yofthe air.(or other :gas

t@ coming from sources 22 and 23 which may be natural air currents) ,carries the particles with it to build up the cloud plumes 20 and 21 shown.

Such methods of controlling cloud formations may be applicable to a number of various problems. First, for example, there is the application of this method of particle charging to the creation and control of thunderstorms. When the charges in clouds 20 and 21 become great enough to create a suiciently intense lield'between them, there will be lightning across the clouds and a subsequent rainstorm.

Industrial applications of this method of charging a cloud of particles include such uses as the removal of particles from a'fluld stream, the atomization of liquids, and the deposition of `finely dividedl particles on areas or points not otherwise easily laccessible for such disposition. Thus, if dust particles are present in a iluid stream, they may be charged and subsequently removed by permitting the stream to pass `an electrode, loppositely charged, at a rate permitting attraction of the dust particles. Likewise, finely divided paint particles may be charged and charges of the opposite sign induced on the object to be painted. The vpaint particles -would be attracted to the object,mak ing it possible .to introduce thepaint into areas diicultly accessible to conventional methods o f spraying, brushing or rolling. In such applications the stream or vcloud not containing particles yto be removed or to be deposited maybe of afliquid or fluid such as Waterdroplets or vapor which .may be recycled .within the system.

I claim: l. A method for building up a rst and a second cloud comprising `particles bearingsubstantially all positive and hich comprises directing a rst stream 0f particles close to, 'but inout of contact relation with, the outer surface of a second electrode in a manner to deposit positive 4charges on said first-stream lparticles and -to accumulate l said positively charged rststream particles into a first cloud of substantial density, directing a second stream O fParticles close to, but in out of .Contact relation with, the outer surface of a rst electrode in a kmanner to `deposit negative charges on said Vsecond-stream particles and to accumulate Vsaid negatively charged second-stream particles into a ysecond cloud of substantial density. Y

2. A method in accordance .withclaim `l wherein said second cloud serves as said second electrode after said irst electrode has been primed V by an outside voltage source, and said vfirst cloud serves -as said first electrode.

References Cited in the lile of this patent UNITED STATES VPTENTS 12,742,581 "Rhodes Apr. 17, 1956

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