US2105614A - Method and apparatus for electric dehydration of emulsions - Google Patents

Description

Jan. 18, 1938. c, ROBERTS 2,105,614

AND APPARATUS FOR ELECTRIC DEHYDRATION OF EMULSIONS 2 Sheets-Sheet 1 METHOD Filed Nov. 10, 1932 CONT 1.. MEAN-5 [NVi/V 7'O&: C/aud/ua HMRober/a A TTORNEY.

Jan. 18, 1938. c. H. M. ROBERTS 2,105,614

METHOD AND APPARATUS FOR ELECTRIC DEHYDRATION OF EMULSIONS Filed Nov. 10, 1932 2 Sheets-Sheet 2 A f/vvz/vroa. C/audiusHM/QcJber/u A TTO/Q/VEK Patented Jan. 18, 1938 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR ELECTRIC DEHYDRATION 0F EMULSIONS Claudius H. signor to of California Beach, Calif as- Company of Calif., a corporation Application November 10, 1932, Serial No. 642,100

Claims.

My invention relates to the art of electrical treatment of emulsions, and finds particular utility in treating petroleum emulsions of the waterin-oil type so as to coalesce the water particles into masses of sufilcient size to be economically separated from the oil. It should not be understood, however, that the invention is limited to this type of emulsion, for it finds utility in treating other types and kinds of emulsions and mixtures. For the purpose of clarity, the invention will be hereinafter described with particular reference to the treatment of petroleum emulsions without limiting myself thereto.

The conventional method of electrically dehydrating such a petroleum emulsion includes subjecting this emulsion to an electric field between a pair ofelectrodes. This electric field is set up by a high intensity alternating potential impressed across a pair of electrodes. In practice the wave form of such an alternating potential is substantially sinusoidal.

The present invention includes among its obiects the utilization of a potential having a steep wave-front, such a potential having been found to be very effective with certaintypes of emulsions, certain of which are otherwise untreatabie by electrical methods. This steep wave-front potential is preferably applied in the form of one or more surges which are very effective in coalescing the dispersed phase into masses of suflicient size to settle by gravity from the continuous phase or to be removed therefrom by other wellknown separating methods.

Also included among the objects of the present invention is the utilization of a condenser to set up such a steep wave-front surge, the invention including both a method and apparatus for first charging this condenser and subsequently discharging it into the input circuit of the electrodes, whereby the surge is conducted to these electrodes and sets up a correspondingly high intensity field therebetween.

In the preferred embodiment of the invention the condenser is charged during the time that a potential difference is impressed across the electrodes and is discharged after this potential difference has been substantially reduced or removed. This is not, however, invariably necessary for in some instances the surge resulting from the discharge of the condenser may be superimposed on another potential continuously applied to the electrodes. Both systems f all within the scope of the present invention.

Other objects of the invention lie in the use of a switch means whereby the condenser can be first charged and subsequently discharged, and also in the vibrator for operating such a switch means to periodically change the connections of the circuit.

So also the circuits utilized are of particular value when treating certain types of emulsions which are otherwise difiicult or impossible of treatment by electric methods, it having been found that these circuits tend to decrease the tendency of the dispersed particles to form low resistance paths between the electrodes, which paths sometimes result in the consumption of excessive amounts of energy.

My experiments have also disclosed that a very desirable treating action accrues from the use of a compound electric field having both direct current and alternating current components. It has been further found that greatly improved results accrue in the treatment of certain types of emulsions if the compound field is so designed that the potential across the electrodes never becomes zero. With such a system the potential across the electrodes would be graphically represented by a curve lying entirely on one side of the zero or abscissa axis, no portion of the curve touching this axis. The result is that there is in effect a unidirectional potential applied to the electrodes at all times, thus permitting such a system to combine the advantages of alternating and direct current systems, and in some instances, to combine with the coalescing action a migrating action whereby the dispersed particles tend to migrate toward one or the other of the electrodes.

Such -a compound field may be provided in a number of ways, but it is one of the objects of the present invention to utilize separate sources of direct and alternating potential, and to incorporate these sources in circuits which isolate the direct current from the source of alternating potential and vice versa.

Such a compound field system may even be used to advantage along with the steep wavefront surges previously described, and such a. system falls within the scope of the present invention. If such a system includes a condenser, it will be found advantageous to charge and discharge the condenser by the source cf alternating potential retaining the source of direct potential connected to the electrodes during the time that the condenser discharges, thus preventing the potential across the electrodes from reaching a zero value.

My experiments also show that the effectiveness of treatment is often dependent upon the potentials utilized.

The application of an alternating field tends to elongate the dispersed particles in step with the alternating potential utilized, and it is a Further objects and advantages of the invention will be made evident hereinafter.

Referring to the drawings- Fig. 1 is a wiring diagram illustrating one embodiment of current and alternating current potentials to the treater.

Fig. 2 is a' graphical representation of the direct current component.

Fig. 3 is a graphical representation of the alternating current component.

Fig. 4 is a graphical representation of the resultant field.

Fig. 5 is a wiring diagram illustrating an alternative system.

Figs. 6 and '7 are graphical representations of resulting field when the circuit shown in Fig. 5

direct current potential.

form of the invention.

Referring particularly to Fig. l, I have illustrated one form of well-known electric treater I 0 and inof treaters may treatment and the invention supplying both direct The source 01 unidirectional potential II is shown as including a motor-generator set comprising a motor 21 energized from a supply line 28 including a switch 29, this motor being con It has been found to be desirable in many ingenerator 30 having a rather pronounced ripple in its output voltage.

It should not be understood, however, that I 'mited to the use of a motor-generator set for setting up this unidirectional potential. It

is entirely possible to use other devices.

vacuum-tube or mercury-vapor type. With such rectifiers it is very easy to obtain the desirable ripple.

The source of alternating potential 26 is shown as including a motor-generator set including an alternating current 43 the output voltage of the alternator 46 can be readily varied.

One terminal of the alternator 45 is connected to a conductor 48 extending to one blade 01 a vice 52 comprising a switch means for periodically breaking the circuit. Such a commutating The other terminal 01' the alternator 45 is connected to a conductor 84 which extends to another blade of the switch II and includes an overload circuit-breaker 55 therein. A choke coil I may be positioned in this conductor and acts as a variable reactance which can be used to regulate the current reaching the switch II.

The switch ll is connected to an input circuit ill of the treater i0. this input circuit being shown as including a step-up transformer I having a primary winding 82 connected across the switch .50. A secondary or high potential winding 83 of the transformer is connected to the inner and outer electrodes through conductors N and 85 respectively. A condenser 68 is positioned in the conductor 84 and serves a dual function. In the first place, this condenser functions to block out the direct current component of the resultant potential applied across the electrodes, thus preventing this direct current component from setting up a current through the secondary winding '3 of the transformer. In the second place, this condenser acts as a storage means, being charged when the transformer Si is energized and being subsequently discharged through the secondary winding 63 and to the electrodes ii and i2 when the transformer is de-energized.

Fig. 3 illustrates a typical sinusoidal wave form developed by the alternator 45. It will be noticed that the line 10 representing this alternating potential extends both above and below the zero or abscissa axis O-X. However, the resultant potential applied to the electrodes includes both the alternating component shown in Fig. 3 and the unidirectional component shown in Fig. 2, the resultant potential being the additive result of these components and being shown in Fig. 4. This resultant potential will be in the form of a curve 12 of general sinusoidal shape on which is superimposed the ripple developed by the source of unidirectional potential. This type of combined high frequency and low frequency wave form is often desirable, regardless of whether or not the resultant curve lies entirely above the zero axis. However, in the preferred embodiment of the invention I have found it extremely desirable when treating certain types of emulsions heretofore difficult or impossible to treat by electrical methods to so regulate the magnitude of the unidirectional and alternating potentials that the resultant curve 12 lies entirely above the zero axis O-X. This result can be accomplished by supplying to the electrodes a unidirectional potential of greater magnitude than the peak potential of the alternating potential. Thus, during the operation of the treater there will be impressed across the electrodes at all times a varying unidirectional potential, the minimum value of which is represented by the vertical distance between the line RS and the zero axis O-X.

The desirable action accruing from such a system can be explained by considering the action which takes place on a water droplet suspended between the electrodes ii and i2. This water droplet will be charged by induction due to its being positioned in an electric field. In addition, it will itself carry certain ionic charges which, in the absence of an electric field, will be uniformly distributed adjacent the interface. The application of an electric field will cause these charges to move to those portions of the droplet which are closest to the electrodes. Thus, the positive charges will be concentrated at one portion of the droplet and the negative charges will be concentrated at a diametrically opposed portion, the equatorial section being substantially free of such ionic charges. The result is that the droplet will be'elongated in such a direction as to tend to bridge between the electrodes, or. in other words, in a direction parallel to the lines of force of the electrostatic field. An increase in the potential applied to the electrodes will increase this elongation of the droplet, and a reversal of potential of the electrodes will cause a reversal of position of these charges on the droplet. Such a reversal in the position of the charges will never take place if the potential impressed across the electrodes does not become zero. Thus, in the system shown, the droplet will tend to elongate in synchronlsm with the variations of the applied potential, and there will always be a unidirectional component of the field acting upon the droplet. Since this droplet carries an inherent charge due to adsorbed ions from the oil, whose companion ions of opposite sign of charge are in the oil and free to move, the particle will thus be drawn toward one or the other of the electrodes, depending upon the sign of the charge. It will thus be clear that in my system the particle is not only subjected to a field of varying intensity, but is also subjected to a unidirectional component which tends to set up a migration of the droplet in the field. This dual action has been found to be very effective with certain types of emulsions, and tends to decrease the tendency of the droplets to form low resistance pathsbetween the electrodes. Even if the direct current component is not made sumciently large to move the curve entirely to one side of the zero axis, advantageous results will still accrue. If this is done the curve will not be symmetrical with respect to the zero axis. Instead, the positive portions of the curve lying above the zero axis will have a different effective voltage from the negative portions lying therebelow. Heretofore in the electrical treatment of emulsions the effective voltages of the positive and negative portions of the wave form have been maintained substantially equal. To make these effective voltages unequal is to set up an unbalanced alternating potential which exerts an unbalanced effect on a dispersed droplet in the field, this action tending to accelerate coalescence and removal of the dispersed phase.

My experiments have shown that the effectiveness of the treatment is dependent upon the frequency developed by the alternator 45. No invariable rule can be given in this regard, but it has been found that there is an optimum frequency at which each individual emulsion treats most effectively. This optimum frequency can be determined by methods of trial and error. This optimum frequency depends upon the values of dielectric constant and resistivity of the oil and brine components of the emulsion and upon the percentage and particle size of the dispersed phase and upon the surface and interfacial tensions of the two components, which properties of the system to be treated in part determine the resonance frequency of the globules of the dispersed phase, it being understood that the term resonance means that frequency at which the rhythmical distortions of the droplets under the action of the alternating component of the applied field occur essentially in synchronism with the free vibration rate of the droplets. In view of the fact that the electrostatic capacity and resistance of an emulsion system are complex and as yet imperfectly determined functions of the above-stated properties and proportions of the components of the system, as well as functions of the dimensions and relative sizes of and gap between the electrodes defining the treating space. and since these properties are also variable funcgradient and frequency applied, it will be understood that no categorical statement of the optimum frequency for treatment of an emulsion can be made, but that this frequency depends upon the manner in which the specific properties of each system cooperate to determine the resonant frequency of the droplets of the dispersed phase.

So also there is a variation between emulsions in so far as the potential supplied from the alternator 45 is concerned.

suits are obtained, that potential at which sufiicient distortion of the droplets, by induced charging, is effected to enable contact and coalescence of the droplets of the dispersed phase, without producing such excessive distortion as to cause additional dispersion of the droplets. Thus, if the potential were raised too high an individual droplet would be extent that it would divide effect that must usually be avoided if best treating action is to be effected. As will be appreciated, without extended discussion, significantly lower potentials will be satisfactory in producing sufficient distortion of the droplets if the frequency of the alternating component has the optimum value.

Since, also, as has been previously stated and as is disclosed in the patent to Cottrell, No. 987,115, the resistance of an emulsion is a function of the potential gradient to which it is subjected and as the resistance of the emulsion is also a function of the frequency of the alternating component of the applied field, it is immediately obvious that the simultaneous application of a direct current potential, superimposed upon the alternating current potential, will operate to alter the optimum frequency and optimum potential which would exist for alternating fields alone. It therefore is apparent that the simultaneous application of the direct current potential, in effect, serves to alter the apparent properties of the emulsion system, so as to permit the alternating field to exert a resolving effect upon the emulsion of which it would not alone be capable.

It should also be noted that a further factor, in determining the frequency and potential of the alternating component and the potential of the direct potential component which together yield optimum results in resolution of the emulsion, resides in suitable choice of the conditions of fluid flow and agitation in the treating space. This arises from the fact, as my experiments have proved, that the conditions of flow and agitation to which the emulsion system is subjected while in the treating space in part determine the resistance and electrostatic capacity of a given system and hence operate to partially determine the resonance frequency of the droplets of the dispersed phase, as well as to affect the degree of distortion of those droplets under a given instantaneous potential gradient. This arises from the obvious fact that the isotropic properties of a heterogeneous liquid system at rest are, in part, altered to anisotropic properties when such a system is subjected to suitable conditions of flow and agitation.

If the commutating device 52 is operated, it will be clear that only a portion of the wave form shown in Pig. 8 will be impressed on the electrodes. Thus, if the commutating device I! is operated synchronously with the alternator II, it

In other in- I: may be op This will result in a steep wave-front surge to the transformer, this surge being transmitted to the electrodes. Such a steep wavefront has been found to give very desirable resuits and is especially valuable in decreasing the short-circuiting tendency of the treater. In the commutator device 52 breaks the circuit to the transformer. the previously charged condenser will discharge in the input circuit 60 and will that a high frequency oscillation is set up therein at the time the commutating device 52 breaks the circuit to the transformer.

front surges in the input circuit 60.

In Fig. 5, I have illustrated another form of the invention in which the electrodes H and it are connected in an input circuit including a transformer II. This transformer may be of the conventional two-winding type or may be in the form of an auto-transformer. In either event,

it will include a primary winding 82 and a secthe numeral I4, the electrode ll grounded. A conductor I5 connects the electrode i! to the high voltage terminal of the secondary winding 83 and I6 is preferin series with this conductor, though in many instances this resistance can be eliminated.

The grounded terminal of the primary winding II is connected to a conductor which is in turn connected to one conductor of a supply line It comprising a source of potential. The other terminal of the primary winding 02 of the transformer is connected to a conductor 94 in which is positioned a resistance II and a condenser 86/ is connected to the supply line ll through a winding ll which preferably surrounds a core 08 whereby this core is magnetized when event the wave 1 current passes through the conductor 04. An auxiliary circuit I00 is connected between the conductor 00 and the line-side of the condenser 90, this auxiliary circuit including a switch IOI which, in conjunction with the winding and core 90, forms a vibrator means well-known in other arts. The switch is shown as including a pivoted armature I02 adapted to engage and disengage a contact I03, being normally held against this contact as by a spring I04. When, however, the current through the winding becomes sufficiently large, the core 99 will act as a magnet to draw the upper end of the armature I02 leftward to break contact with the contact I03.

In considering the operation of this form of the invention, let it be assumed that the switch means IOI is open. At this time current from the supply line will flow through the winding 98 and through the conductor 94 and will simultaneously charge the condenser 06 and energize the transformer III, the current returning to the supply line through the conductor 90. The energization of the primary winding 82 will, of course, energize the secondary winding 83, thus impressing across the electrodes I I and I2 9. potential de pendent upon the potential of the supply line. When, however, the armature I02 comes into engagement with the contact I03 the circuit conditions are entirely changed. At this time the auxiliary circuit I00 is connected directly between ihe conductors 50 and 94 so that current from the supply line moves through the winding 88 and through the auxiliary circuit I00 returning through the conductor 90. The winding 98 acts as a choke in this regard and the impedance of this winding may be sufilcient to prevent excessive current flowing at this time. In addition, however, a resistance I06 may be positioned in the conductor 90 to further limit this current flow if desired.

Considering the conditions which take place on the load side of the switch IOI when the contacts of this switch close, it will be clear that two things simultaneously occur. In the first place, the closing of the switch IOI isolates the load with respect to the supply line so that the potential previously applied from the supply line is cut oil. In the second place, as soon as the switch IOI closes, the condenser 96 discharges into the input circuit of the treater. Considering the latter phenomenon in detail, it will be clear that the energy previously stored in the condenser 98 will be dissipated in the form of one or more steep wave-front surges of current which flow through the closed circuit including he switch "II, the primary winding 82, and the resistance 95. Whether or not this circuit is aperiodic will depend upon the characteristics of the elements therein. By particular design the condenser may be made to send only a single surge through the primary winding 82 oi. the transformer. On the other hand, it is possible to design this closed circuit 50 that an oscillatory high i'requency current will be set up therein in which event a series of steep wave-front surges will be delivered to the primary winding 82. It will be clear that these surges are transmitted to the secondary winding 03, and thus delivered to the electrodes II and I2.

It will be clear that the armature I02 will be actuated in response to the current flowing through the winding 00. The circuit is so designed that the magnetic pull of the armature 00 when in circuit with the condenser 06 and the primary winding 02 will be insufficient to draw the armature I02 leftward, and under these circumstances the armature will move Into engagement with the contact IIII. As soon as this en- 'gagement takes place the current through the winding 98 is greatly increased and as soon as the magnetic flux builds up sufficiently the ar-- mature I02 will be drawn leftward to open the switch IOI.

The supply line 9| may be energized either by a unidirectional or alternating potential. 1! connected to a source of unidirectional potential, the wave form developed between the electrodes II and I2 will be somewhat as shown in Fig. 6. The instant of time when the armature I02 breaks contact with the contact I03 is indicated by the dotted line IIO, the instant 01' time at which these members come into engagement being indicated by the dotted line III. Thus, during the interval of time between these instants and indicated by the letter A, the condenser 00 will be charging, and asmall current will pass through the winding 82 of the transformer which will in turn induce a relatively small potential across the electrodes II and I2, as shown by that portion of the curve below the zero axis. As soon as the armature I02 engages the contact I03 the condenser discharges, sending a steep wave-front surge through the winding 02 and inducing in the winding 83 a corresponding steep wave-front surge indicated by the numeral II3. If the circuit is properly designed only one surge will take place before the armature I02 breaks contact with the contact I03 at an interval of time indicated by the numeral Ill. Thus, during the interval B a single steep wave-front surge will be impressed across the electrodes.

If, however, the circuit is so designed as to have oscillatory characteristics, this single surge will be replaced by a series of high frequency surges which may take the wave form shown in Fig. '7, the interval A indicating the period of charge of the condensers, and the interval B indicating the period during which the condenser discharges so as to set up a plurality of steep wave-front surges [I0 during this interval.

If the supply line 9| is connected to a source of alternating potential, the wave form will be somewhat different, Fig. 8 roughly indicating one form which this potential may assume. Here the letter A represents the interval of charge of the condenser, while the interval B represents the interval during which the condenser discharges to set up a single steep wave-front surge I20 across the electrodes. The subsequent period of charging oi. the condenser 96 is indicated by the letter A, while the subsequent period of discharge is indicated by the letter B' and produces a steep wave-front surge I2I. The second surge will be in the opposite direction from the first surge, if the switch means I M is operated at double the frequency of the incoming alternating potential. If this switch means operates promiscuously, the wave form shown in Fig. 8 will be somewhat varied depending upon the portion of the alternating current cycle upon which the switch means IOI closes and opens.

In Fig. 9 I have illustrated the action which takes place if an alternating current is supplied and if the circuit including the winding 82, the condenser 96, and the switch means IN is of an oscillatory character. Here during the interval B or B representing the periods during which the switch means IN is closed, a plurality of steep wave-front surges I22 will be impressed across the electrodes. Stated in other words, an

oscillating current of high frequency will flow through the circuit and will induce high frequency surges of steep wave-front across the electrodes. The wave-front obtainable will, of

will be somewhat di erent.

In Fig. 10, I have shown an alternative mode of connection in which the supply line is indicated by the numeral I30. A conductor I3I is in series with the resistor I32 and conducts current to a winding I33 of the described. A conductor I3! is connected to both the windings I33 and I35 and is also grounded, this conductor extending to a ductor I42 to the winding I39 which is in turn connected to the line I30, as shown. ductor I42 extends between the conductors HI and I and includes a condenser I45 and a resistor I46 in series therewith.

It will thus be clear that when the switch means I38 is closed current may flow through two parallel paths. The first of these may be termed a main circuit and includes the resistor switch means I38, the conductor H2, and the winding I38. The second may be termed a supplementary circuit and includes the resistor i 32, the conductor I3I, the resistor I46, the condenser M5, the conductor H2, and the winding I39. relative amounts of the these circuits is dependimpedances thereof. Usually the current flowing through the winding i33 is greater than that flowing through the conductor I44, though this is not necessarily the case in all instances. In any event the combined that this armature falls back and again engages the contact MI. At this instant the potential of the supply line i30 is again placed across the winding I33 and it will also be clear that the condenser I45 will discharge through a closed circuit including this condenser, the switch means I38, and the winding I33. The sudden The resultant surge is impressed across the electrodes II and I2 to produce the desirable treating action hereinbefore described.

The switch means I38 may be operated either synchronously or promiscuously, as previouslyset forth, and the supply line I30 may be energized either by unidirectional potential or alternating potential. The wave forms obtained will be of the same general nature as those shown in otherwise hard to these electrodes. is in series with the electrodes.

(if one is used), the condenser discharging thereinto in either instance. It should thus not load side of the condenser or on the line side thereof.

Various other modifications will be apparent to those skilled in the art and fall within the scope of this invention.

It will be clear also be utilized in con unction with other known tions of which is quency wave; impressing the resultant potential between said electrodes; and subjecting the emulsion to be treated to the action of the electric field thus set up between said electrodes.

trodes.

3. In an electric treater for treating emulsions, the combination of: a pair of electrodes defining a transformer connected to said electrodes; a condenser in circuit with said trans- Process and former and storing electric energy during the time said transformer is energized; a source of potential; and switch means for periodically energizing said transformer from said source of potential and subsequently deenergizing said transformer to permit said condenser to discharge to set up a steep wave-front surge to said electrodes.

4. In an electric treater for treating emulsions. the combination of: a pair of electrodes between which is positioned the emulsion to be treated; a potential supply means; a condenser connected in circuit with said potential supply means; an input circuit connected to said potential supply means through said condenser and connected to said electrodes to set up an electric field therebetween; an auxiliary circuit connecting said condenser in closed circuit with said input circuit whereby said condenser can discharge into said input circuit through said auxiliary circuit; and a switch means in said auxiliary circuit for periodically closing same to discharge said condenser into said input circuit.

5. In an electric treater for treating emulsions, the combination of: a pair of electrodes between which is positioned the emulsion to be treated; a potential supply means providing a pair of conductors; a transformer connected to said electrodes and supplied with current from said potential supply means; a condenser connected to said transformer, the line side of said condenser being connected to one of said conductors; and switch means for periodically connecting the line side of said condenser to said transformer to discharge said condenser into said transformer to send a steep wave-front surge to said electrodes.

6. In an electric treater for treating emulsions, the combination of: a pair of electrodes between which is the emulsion to be treated; a transformer providing a primary and a secondary winding, said secondary winding being electrically connected to said electrodes to build up a potential difference therebetween; a condenser; means for charging said condenser; and switch means operating periodically and connecting said condenser in closed circuit withsaid primary winding whereby the charge on said condenser is delivered to said primary winding to provide a steep wave-front surge to said electrodes.

7. In an electric treater for treating emulsions, the combination of: a pair of electrodes between which is positioned the emulsion to be treated; a potential supply means providing a pair of conductors; a magnetic means including a winding ternating potential and said source of unidirectional potential to said electrodes whereby the resultant potential difference between said electrodes never drops to zero during the application of said potentials and means for periodically isolating one of said sources from said electrodes for only a short period of time during the time said other source is connected thereto.

9. A method of electrically treating an emulsion between electrodes, which method includes the steps of applying an alternating potential across said electrodes; electrically biasing said electrodes by applying thereto a unidirectional potential; and periodically disconnecting and reapplying one of said potentials to said electrodes while the other potential remains applied thereto.

10. A method of electrically treating an emul sion between electrodes by the use of a source of alternating potential and a condenser, which method includes the steps of energizing said electrodes and charging said condenser by connecting said source of alternating potential thereto; then isolating said source of alternating potential from said electrodes; and discharging said condenser to said electrodes during said isolation of said source of alternating potential therefrom whereby said emulsion is first subjected to a field set up between said electrodes by said source of alternating potential and is then subjected to a steep wave front surge developed by the discharge of said condenser.

11. A method of electrically treating an emulsion between electrodes by the use of a source of alternating potential and a condenser, which method includes the steps of energizing said electrodes and charging said condenser by connecting said source of alternating potential thereto; then simultaneously isolating said source of alternating potential from said electrodes and discharging said condenser thereto to form a surge to said electrodes at the extreme end of the period of application of said alternating potential whereby said emulsion is first subjected to a field set up between said electrodes by said source of alternating potential and is then immediately subjected to a steep wave front surge developed by the discharge of said condenser; and subsequently re-energizing said electrodes and said condenser.

12. A method of treating an emulsion between electrodes, which method includes the steps of applying to said electrodes an alternating potential; simultaneously electricallybiasing said electrodes by applying thereto a rippled direct curing and said switch means in series when said rent potential, the frequency of the ripple being 55 much greater than the frequency of said alternating potential; and subjecting the emulsion to the resultant field produced between said electrodes to coalesce the dispersed phase of said emulsion.

13. A method of electrically treating an emulsion including a continuous phase with dispersed liquid particles therein, which method includes the steps of impressing across an electrodebounded treating space an alternating potential 65 of a frequency substantially corresponding to the in circuit with one of said conductors; a switch means operated in response to the current flowing through said winding and connected to said winding and to the other of said conductor means whereby current flows through said windswitch means is closed; an input circuit connected to said electrodes; condenser means connected to said input circuit to discharge therein; and means connecting said input circuit and said condenser across said switch means whereby closing of said switch means discharges said condenser therethrough and into said input circuit.

8. In an electric treater for treating an emulsion, the combination of a pair of electrodes be-- tween which is positioned the emulsion to be treated; a source of alternating potential; a source of unidirectional potential delivering a unidirectional potential of a magnitude greater than the peak potential of said alternating potential; means for connecting said source of alelectrically biasing said electrodes with a unidirectional potential to produce a resultant field; and causing coalescence of said dispersed liquid 70 particles by subjecting said emulsion to the action of said resultant field.

14. In an electric treating system for treating an emulsion, the combination of: a pair of electrodes. between which is positioned the emulsion 75 to be treated; a source of unidirectional poten-- tial; means connecting said source 01' unidirectional potential across said electrodes; a source 01' alternating potential; means for connecting said source of alternating potential across said electrodes; a condenser means in circuit with said last-named means and preventing any of said unidirectional potential from reaching said source of alternating potential; and means for periodically discharging said condenser means to said electrodes.

15. A method of electrically treating an emulsion between electrodes by the use of a potential source and a condenser, which method includes the steps of: charging said condenser before conconnection of said trodes.

16. In an electric treating system for emulsions, the combination of: means;

means electrically connecting said potential supply means to said electrode-energizing conductor means; switch means connected across .said circuit means; means for periodically closing said switch means to periodically shunt said circuit means to decrease the normal potential applied to said electrodes by said potential supply means; and a condenser in series circuit with said electrodes and said switch means when said switch means is closed whereby closing of said switch means also CERTIFICATE Patent No 2,105, 611;.

particles forming the dispersed phase or said emulsion.

1'7. A method 01 treating an emulsion containing an aqueous phase dispersed in a continuous phase, which method includes the steps of: mov- 18. A method as defined in claim 17 in which said electric field is established by impressing across spaced portions of said treating space a potential and a unidirectional of a magnitude less than the peak potential of said single alternating potential.

19. In combination in a system for treating emulsions: a pair of electrodes bounding a treating space containing emulsion to be treated; a source of potential; a condenser; circuit means connecting said electrodes, said source of potential, and said condenser to energize said electrodes and establish an electric stress in said treating space; switch means in said circuit means for charging said condenser and discharging same to said electrodes; a movable member operating said switch means; and magnetic means providing a winding in said circuit means primary winding of said transformer.

CLAUDIUS H. M. ROBERTS.

OF CORRECTION.

'January 18, 1958.

CLAUDIUS H. M. ROBERTS.

of the above numbered patent requiring correction as follows: Page 8, first column, line 59, claim 16, for the word "electrodes" gizing conductor means;

the case in the Patent Office.

(Seal) read electrode-enerand that the said Letters Patent should be read Henry Van Arsdale, Acting Commissioner of Patents.

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