US3148133A

US3148133A - Electric treater and method

Info

Publication number: US3148133A
Application number: US49702A
Authority: US
Inventors: Delber W Turner
Original assignee: Petrolite Corp
Current assignee: Baker Petrolite LLC
Priority date: 1960-08-15
Filing date: 1960-08-15
Publication date: 1964-09-08
Anticipated expiration: 1981-09-08

Description

Sept. 8, 1964 D. w. TURNER ELECTRIC TREATER AND METHOD 2 Sheets-Sheet 1 Filed Aug. 15, 1950 j/reurwe ,5! //s Arrow/2 's.

Sept. 8, 1964 D. w. TURNER ELECTRIC TREATER AND METHOD 2 Sheets-Sheet 2 Filed Aug. 15, 1960 o o o o o o o 0 0 0 0 o o W J um/Ee,

United States Patent "ice 3,148,133 ELECTRIC TREATER AND METHOD Delber W. Turner, Houston, Tex, assignor to Petrolite (Iorporation, Wilmington, Del, a corporation of Delaware Filed Aug. 15, 1960, Ser. No. 49,702 6 Claims. (Cl. 204-188) My invention relates to electric treaters for the resolution of oil-continuous emulsions and more particularly to a novel high-throughput electric treater and method particularly suited to the resolution of emulsions formed in the process of desalting crude petroleum stocks, although applicable also to the treatment or resolution of other emulsions or dispersions.

In the electric desalting process it has been common in recent years to emulsify a relatively fresh water with a salty crude and resolve the emulsion by use of highvoltage electric fields under conditions of relatively high turbulence. In resolving large-volume streams, it has been proposed to divide the stream into smaller streams and treat the latter by separate electrode systems disposed in the same or different containers. I have discovered that the treatment of such large-volume streams is better and more economical if the entire stream is preliminarily treated in a relatively turbulent zone containing a single electrode system, at least part of the treated emulsion constituents being transferred Without substantial emulsification to a second zone laterally opposite the first zone for additional treatment and/or separation. It is an object of the invention to provide such a treating system and method. Another object is to treat emulsions electrically by successive flow through a turbulent zone and a quiescent or relatively quiet zone, these zones being disposed in different portions of the same generally-horizontal container. In this connection it is an object of the invention to provide an upright flow-control barrier means dividing the interior of a horizontally elongated container into two zones or" the aforesaid types. A further object is to transfer oil-continuous material from a pretreating zone to a subsequent horizontally-elongated zone with little or no emulsification and in a minimum of space.

It is a further object of the invention to introduce an oil-continuous emulsion, whether or not the residual emulsion from a pretreating step, into one end of a substantially horizontal chamber or passage having a collection trough in its lower end, the introduction being through a pattern of discharge orifices distributed throughout a cross-section of the passage above the collection zone, to subject the resulting emulsion stream to one or more high voltage electric fields, and to withdraw oil-continuous material from the far end of the passage to establish a uniform flow through successive crosssections of the passage above the collection zone. Another object is to flow such resulting emulsion stream through pairs of electrodes so spaced or arranged in the flow direction that while intense fields are established between the electrodes of each pair or set the voltage gradients in the spaces between the pairs or sets will be so low as not to disturb settling of the dispersed material while the emulsion is advancing along such spaces. A further object is to withdraw the oil-continuous material from such far end of the passage through a pattern of outlet orifices to assist further in establishing such uniform flow.

Still a further object of the invention is to provide an electric treater in which a high-voltage electrode can be grounded to the container from a position outside the 3,148,133 Patented Sept. 8, 1964 container. A further object is to provide a novel electric circuit incorporating a switch inside the treater which can be actuated with safety from a position outside the container.

Further objects and advantages of the invention will be apparent to those skilled in the art from the following description of exemplary embodiments of the invention.

Referring to the drawings:

FIG. 1 is a vertical sectional view of one embodiment of the invention;

FIGS. 2 and 3 are sectional views taken along corresponding lines of FIG. 1;

FIG. 4 is a sectional view taken along the line 44 of FIG. 1 with the closet electrode broken along the vertical midplane of the treater to expose the next electrode;

FIG. 5 illustrates an alternative flow-control barrier means, FIG. 6 being a cross-sectional view taken along the line 66 of FIG. 5;

FIG. 7 illustrates a further alternative flow-control barrier means; and

FIG. 8 is a sectional view taken along the line 88 of FIG. 7.

FIG. 1 shows an electric treater 9 having a substantially horizontal pressure container 1t), which may be of cylindrical or other cross-section, closed at its ends by domed heads 11 and 12. An upright flow-control barrier means 15 divides the interior of the container into sideby-side zones hereinafter referred to as a first or pretreating chamber 16 and a second or separating chamber 17. The latter is usually of much greater horizontal length than the former. Both are filled with liquid preceding and during operation of the treater.

Exemplifying a use of the invention in electrically desalting a salty crude oil, FIG. 1 suggests the usual pumps 20 and 21 respectively pressuring streams of salty oil and relatively fresh water which are brought together at a junction 22 and additionally emulsified by a mixer such as a valve 23. A large-volume stream of the resulting emulsion is delivered to a distributor 25 to discharge into the first chamber 16 in a manner to establish a relatively high turbulence therein. The distributor shown includes a depending pipe 26 having a flared section at its lower end across which extends a head 27. This head is movable toward and away from the flared sec tion of the pipe 26 by turning a handwheel 2S and is rotatable relative to such flared section by turning a handwheel 29 to respectively adjust the width and clean an annular orifice between such head and such flared section. This annular orifice additionally emulsifies the stream and forms the emulsion into a thin sheet jetting radially outward from the distributor 25 as suggested by arrows 30.

An emulsion-treating electric field is established in the first zone 16 by any suitable means. As shown, two hori zontal grid-like electrodes 33 and 34 are suspended from insulators, not shown, forming a main treating space 35 therebetween. An auxiliary treating space 36 is formed between the lower electrode 34 and a body 33 of dispersed phase material settling from the treated emulsion in the lower end of the chamber 16. Another auxiliary treating space 39 is formed above the upper electrode 33, here between this electrode and a baflle 4-9 which is electrically connected to the container It). A transformer 41 has two high-voltage terminals respectively connected to the electrodes 33 and 34 through bushings 42 and 43, shown purely diagrammatically, to develop between these electrodes a voltage double that between either electrode and ground. This establishes an electric field in the main treating space 35 that is twice the voltage of the fields in the auxiliary treating spaces 36 and 39. This effect can be obtained by a transformer system having two secondary windings grounded at 44 or a center-tapped secondary winding similarly grounded. The container 1% is grounded at 45. A current-limiting choke 46 is shown in the primary circuit of the transformer.

While not essential to the invention, the distributor dis charges directly into the main treating space 35. It establishes toroidal-like recirculations suggested by arrows 4-8 and 49, the latter circulation being largely confined below the bafile 49. The distributor-electrode ar rangement of FIG. 1 is one of many that can be used to treat the emulsion under conditions of relatively high turbulence in the chamber 16. The electric fields in this chamber coalesce the dispersed phase material of the emulsion, some of the coalesced material settling to form the body 38. Above this body the remaining treated emulsion constituents form an oil-continuous body of decreasing content of dispersed phase material toward the upper portion of the chamber.

The flow-control barrier means of FIG. 1 includes a partition 52 extending completely across the container, traversed by a collector pipe 53 opening at one end on the upper portion of the chamber 16 and at its other end on a depending header pipe 55 closed at its lower end below a horizontal baffle 57 which is at approximately the upper boundary of a collection trough 58 along the bottom of the second chamber 17. Pipe branches 69 extend outward from the header pipe 55 and carry a large number of discharge orifice members or nipples 61 having corresponding discharge orifices arranged in a pattern occupying substantially the entire cross-section of the chamber 17 above the collection trough 58. The dis charge orifices are each smaller in cross-section than the branches 69 to which they are attached, thus metering and discharging smaller streams of the oil-continuous material of substantially equal velocity and volume. These smaller streams discharge throughout the aforesaid pattern thus producing a large quiet or tranquil stream moving rightwardly along the chamber 17 at substantially equal forward velocity in all its portions. This large stream fills that portion of the chamber 17 above a body of settled dispersed phase material 63 in the collection trough 58.

Production of such a uniform-flow stream is facilitated by mounting circular spreader members 65 respectively in front of the orifices, each such spreader member having a circular periphery concentric with the extended central axis of the corresponding orifice. Each spreader member 65 may be supported forwardly of the corresponding orifice member 61 in the path of the stream by any suitable arm means 66 only one of which is shown in FIG. 1. The spreader members 65' may be figures of revolution about the corresponding extended axes but are shown as thin circular discs.

The creation of such a uniform-flow stream is facilitated also by employing a similar upright bank of outlet orifices at the opposite or exit end of the chamber 17 arranged in a pattern occupying substantially the entire cross-section of the chamber above the collection trough 58 and positioned adjacent the domed head 12. As suggested in FIG. 1, a header pipe 68 is curved to correspond to the head 12 and provides an exit branch 69, extending to the exterior of the container, and a plurality of curved pipe branches 7%) along which the outlet orifices are positioned in the aforesaid pattern. Outlet orifice members or nipples 71 respectively provide the outlet orifices and while such orifices may face in any direction the preferred arrangement is to face them toward the oncoming large stream wherefore the orifice members 71 may be elbows. Again, a more uniform-flow large stream is obtained if speader members 73 are mounted by each orifice member 71 in the path of the entering stream with a circular periphery of the spreader member concentric with the extended axis of the outlet orifice.

it is usually desirable to establish one or more electric fields in the second chamber 17 to act on the oil-continuous material of the large stream to coalesce residual dispersed material therein, the coalesced material settling to the body 63 in the collection trough 58 as the stream advances. Various electrode systems can be utilized, preferably those having horizontally-spaced vertical electrodes with treating spaces therebetween. As shown in FIG. 1, these electrodes are grid electrodes arranged in sets spaced from each other lengthwise of the container a distance substantially greater than the spacing of the electrodes of a set. Each of the upstream and intermediate sets includes electrodes 75 and 76 spaced to define a treating space 77 therebetween, the downstream

set including electrodes

78 and 7 of slightly different constructions for reasons later set forth. By this arrangement the advancing residual emulsion is subjected periodically to coalescing electric fields in the treating spaces 77 with intervening periods of flow through relatively long settling spaces 80 wherein the voltage gradient is so low as not to disturb efiicient settling by electrical windage or other electrokinetic effects. By appropriate electrode connec tions the electrodes at the entrance and exit ends of each space 8-0 can be of the same polarity thereby eliminating fields in these spaces 80. As shown, however, the polarity pattern of each electrode set is the same but the sets are spaced apart a distance several times the spacing of the electrodes of each set, preferably by a factor of about 6 or more. As exemplified, two upper bus bars 81 and 82 traverse the electrodes 75 and 78, being suspended from insulators 83 and electrically connected to the electrodes 75. Two lower bus bars 84 and 85 traverse the electrodes 76 and 79 being suspended from insulators 86 and electrically connected to the electrodes 76 in the illustrated embodiment.

Each electrode is made of horizontal rods 88 traversing and spaced by vertical frame members, the rods varying in length at different elevations so that the ends of the rods lie in a pattern corresponding to the cross-section of the container. The lowermost rod 88' of each electrode is above the body 63 and parallel to the surface thereof.

Each electrode 76 includes frame members 90 and 91 attached to and supported by the bus bars 84 and 85; also shorter frame members 92 and 93 supporting the uppermost rods and those rods that are between the bus-bar passages 94 and 95, these passages being free of rods to pass the bus bars 81 and 82. Braces 96 maintain a fixed angle between the electrodes 76 and the bus bars 81, 82.

Each electrode 75 includes frame members 97 and 98, shown in dotted lines in FIG. 3, attached to and supported by the bus bars 81 and 82. No large bus-bar passages are needed in these electrodes but braces 99 between the electrodes and the supporting bus bars maintain these electrodes parallel to the corresponding electrodes 76.

High-voltage electric fields are established in the treating spaces 77. In the system shown, the electrodes 75 and 76 of each set can be maintained at above-ground potential to establish double-voltage fields in the treating spaces 77, as compared with single-voltage fields between either electrode and any adjacent grounded element. Two properly phased transformers 106 and 101 can accomplish this result, as can also two high-voltage D.C. sources if the latter are used to establish D.C. fields in the second chamber 17. Such D.C. fields are particularly desirable when treating distillates or petroleum fractions containing only small amounts of dispersed phase material.

As shown, the high-voltage terminal of the transformer 1th is connected through the conductor of a bushing 103 and through a conductor 194 to one or both of the bus bars 81, 82 to maintain the electrodes 75 at a potential above ground. Similarly, the high-voltage terminal of the transformer 191 is connected through a bushing 106 and a conductor 107 to one or both of the bus bars 84, 85 to maintain the electrodes 76 at a potential above ground during normal operation of the treater. Switches 108 and 109 energize the primary windings of the transformers 100 and 101. These transformers are provided with current-limiting means, exemplified as choke coils 110 and 111 in the respective primary circuits.

The arrangement for energizing and supporting the electrodes 78 and 79 is somewhat different and can be used on any one or all of the electrode sets if desired. The electrode 78 may be like the electrode 75, modified to provide an extra frame member 115 producing a bus-bar passage 116 for the bus bar 81, see the left half of FIG. 4. Likewise the electrode 79 may be like the electrode 75 but provides a bus-bar passage 117 larger than the passages 94, 95. This is made possible by using two frame members 118 and 115 offset from each other, see the right half of FIG. 4. The end of the bus bar 85 passes through the passage 117 without direct contact with the electrode 79. The electrodes 78 and 79 are suspended in spaced relationship by insulators 122 and 12 3, see FIG. 1.

Each electrode 78 and 79 can be selectively connected to the corresponding bus bar 81 and 85 by a switch means operable from the exterior of the container. Likewise, each of these electrodes can be selectively grounded from such exterior position. The switch means for the electrode 78 includes a switch arm 125 pivoted to and electrically connected to the frame member 115, being biased upwardly as by a spring 126 into engagement with an end portion of the bus bar 81, the latter thus acting as a switch contact. Any suitable means may be provided for actuating this switch means from a position outside the container. As shown, a rod 128 is mounted and guided by a stufiing box 129 and carries a knob 1313 outside the container, the rod being grounded to the container as indicated at 131. When this rod is in the position shown, the switch means is in a closed or electrode-energizing position connecting the electrode 78 to the bus bar 81. When fully depressed, the rod engages the switch arm 125 and swings same from engagement with the end portion of the bus bar 31 to disconnect the electrode 7 8 from the bus bar and ground the electrode. If this is done while the treater is energized there will be a momentary shortcircuiting of the bus bar 81 when the switch arm is first contacted by the rod and before the switch arm separates fr'o mthe end portion of the bus bar. The choke coil 110 limits the short-circuit current during this short period of time and protects the transformer against damage. In like manner the electrode 79 can be selectively energized or grounded by a corresponding switch arm 135 pivoted to the frame member 53 and biased by a spring 136 into engagement with an end portion of the bus bar 85 acting as a switch contact. A grounded rod 138 passes through a stuffing box 139 to actuate the switch arm 135 as before.

It is desirable in this embodiment to be able to control the depths or levels of the bodies of dispersed

phase material

38 and 63 independently. The dotted lines 38a and 63a represent such levels or transition zones between oil-continuous and dispersed-phase-continuous materials respectively above and below such lines. Better treatment and larger throughputs will usually result from carrying a higher level 38a in the first chamber 16 than in the second chamber 17.

To accomplish such independent control, FIG. 1 shows a pipe 155 having a T-intake from the body 38 and a rearward-directed discharge into the body 63 within the space below the baffle 57. The pipe 150 preferably extends to a position outside the container and forms the sole intercommunication between the

chambers

16 and 17 at their lower levels. Flow through the pipe 150 is adjustably throttled by a valve 151 that may be manually controlled but which is preferably a spring-biased valve controlled by any suitable means responsive to the depth, volume or level of the body 33 to maintain the level 38a substantially constant. As diagrammatically suggested, the setting of the valve 151 is controlled by pneumatic pressure applied to an actuating unit 152 through an airline 153 connected to a chamber 154 of a controller 155. Compressed air from a storage tank 157 and a pressure regulator 158 is supplied at constant pressure through an airline 159 to a chamber 16th of the controller 155. A valve 161 controls and adjusts the small air flow from the chamber 16@ to the chamber 154- and thence to the atmosphere through an adjustable bleed valve 162.

The position of the valve161 is controlled by a rod 164 depending through a suitable seal at the junction of the rod and the container, this rod carrying a vertically elongated float 165 of such density as to rise or be buoyant in the settled material of the body 38 but sink in the oilcontinuous material of the body 51). If the level 38a rises the valve 161 restricts the air flow into the chamber 154. As the setting of the bleed valve 162 remains constant, the pressure in the chamber 154 is correspondingly reduced and the spring-biased valve 152 opens a corresponding degree to increase the flow from the body 38 to the body 63. When the level 38a drops below that desired, the float 165 admits more air to the chamber 154 to increase the pressure therein and restrict the flow through the valve 151. Such actions are independent of variations in the volume of emulsion discharging from the distributor 25. Changes in the desired level 38a can be made by changing the pressure of the regulator 153 or changing the setting of the bleed valve 162.

In similar fashion the level 63a in the chamber 17 is independently controlled by a valve 176 in an effluent pipe 171 withdrawing settled material from the body 63, preferably near the downstream end thereof to establish in the body 63 a flow paralleling the flow of oil-continuous material in the large stream thereof. This is accomplished by use of a float 172 controlling a valve 173 to the inlet chamber 174 of which is connected to the line 159 and the outlet chamber 175 of which is connected by a line 176 to the valve 170.

As the large stream of oil-continuous material moves tranquilly along the chamber 17 it is often advantageous to supply additional conducting material thereto as droplets settling through the stream. Thus water can be supplied to manifolded spray pipes 178 positioned along the upper interior of the chamber 17 respectively providing orifices 179 distributed therealong, preferably at positions above the relatively long spaces 80 between the electrode sets. These orifices form the water into drops of larger size than those of the residual dispersed material in the oil-continuous stream. In the electric desalting process the medium added through the pipes 178 will usually be some of the relatively fresh water from the pump 21. If the liquid added through the pipes 178 is a wash medium it will serve to wash the advancing oil of the main stream between periods of intense electric stress and pick up and remove additional materials or impurities therefrom that are soluble in such medium. The electric fields in the treating spaces between the electrodes 75, 76 and the electrodes 78 and 79 will act to coalesce the residual dispersed material or impurities with any of the newly added droplets that have not settled from the stream in the spaces 30, forming larger droplets or masses which settle more rapidly to the collection trough 58. Such a treat-wash-treat-Wash, etc., sequence is particularly desirable on some oils when treated oils of maximum purity are required.

In the embodiment of FIGS. 5 and 6 the levels of the

bodies

38 and 63 are substantially the same in the

chambers

16 and 17, the pipe 150 being eliminated. Here the flow-control barrier means 15 comprises a perforated partition wall having orifices 186 throughout. Each orifice preferably faces a circular spreader member 187 similar to the members 65 previously described. This embodiment has the unique action of discharging into the chamber 17 oil-continuous material of different composition at different levels. Remembering that the body 50 in the chamber 16 varies in content of dispersed material throughout its depth in the sense of having a decreased 'content thereof toward the top, it is apparent that each orifice 186 conducts material of a composition determined by its elevation. The large tranquil stream in the chamber 17 thus starts with the same differences in composition as present in the body 50 in the chamber 16. At the same time, the wall 185 converts a turbulent body into a tranquil stream flowing longitudinally of the second chamber 17.

Similar actions take place in the embodiment of FIGS. 7 and 8 where the flow-control barrier means 15 is a wall 190 and the spaces between its periphery and the inner wall of the container. Such peripheral spaces 191 here substitute for some or all of the orifices 186 of the embodiment of FIGS. and 6. Thus while it is usually desirable to provide orifices 192 in the wall 199, it is possible to dispense therewith in less critical systems or where less than optimum results can be tolerated, relying on the peripheral spaces 191 to supply to the second chamber 17 the oil-continuous material of different composition at the difierent levels of the first chamber 16. The wall 190 is disposed opposite the electrodes 33, 34 and the distributor 25 and thus blocks the highest-turbulence zone of the chamber 16 from the chamber 17. The wall 190 may be mounted from the container by a plurality of brackets 195 traversing the peripheral spaces 191.

Various changes and modifications can he made without departing from the spirit of the invention as defined in the appended claims.

I claim as my invention:

1. A method of electrically treating an oil containing dispersed particles to separate the latter from the oil, which method includes the steps of: establishing highvoltage electric fields in treating spaces spaced from each other along the length of a horizontally elongated passage, there being settling zones between such treating spaces, the horizontal width of each settling zone greatly exceeding the horizontal width of each treating space; forwardly flowing a stream of such oil horizontally along said elongated passage and successively through the treating spaces and the intervening settling zones; discharging into each of said settling zones directly into the oil therein added particles of a wash medium larger in size than said dispersed particles and of higher electrical conductivity and density than said oil, the added particles of wash medium dropping by gravity transversely of the oil stream toward the bottom of said passage; controlling the forward flow rate of said oil stream to carry into each treating space at least some of the larger particles of wash medium discharged into a preceding settling zone, the electric field in such treating space being of sufiicient intensity to coalesce particles of the oil stream with such residual larger particles of wash medium to form coalesced masses settling to the bottom of said passage; withdrawing from the bottom of said passage the coalesced masses and any larger particles settling thereto; and withdrawing oil from said passage at a position downstream of said treating spaces.

2. An electric treater for oil-continuous dispersions, said treater including in combination: a container providing a chamber much longer in horizontal length than in height having a collection trough in the bottom thereof; means for flowing a tranquil stream of the oil-continuous dispersion from end to end of said chamber; a plurality of electrode sets dividing the length or said chamber into settling spaces and interelectrode treating spaces, each electrode set including two upright foraminous electrodes in said chamber above said trough in the path of said tranquil stream and spaced horizontally from each other to define one of said interelectrode treating spaces therebetwcen, said settling spaces being between adjacent electrode sets and at opposite ends of said chamber between each end set and the corresponding end of said chamber, the width of said settling spaces measured horizontally being substantially greater than the horizontal spacing of the electrodes of each set, said tranquil stream of oil-continuous material flowing successively through an interelectrode treating space, a settling space, an other interelectrode treating space and so on in its flow from end to end of said chamber; means electrically connected to said electrodes establishing a high-voltage electric field in each interelectrode treating space, material settling from said tranquil stream collecting in said collection trough; a pipe withdrawing settled material from said collection trough; and means for discharging into said tranquil oil-continuous stream droplets of a wash medium of greater density and electrical conductivity than said oil-continuous material, said last-named means including pipe means providing drop-forming orifices above the spaces between said sets of electrodes, and means for delivering to said pipe means a stream of said wash medium.

3. An electric treater for oil-continuous dispersions, said treater including a chamber much longer in horizontal length than in height having a collection trough in the bottom thereof; means for flowing a tranquil stream of the oil-continuous dispersion from end to end of said chamber, said means including an upright bank of discharge orifices at one end of said chamber arranged in a pattern occupying substantially the entire cross section of said chamber above said collection trough, an upright bank of outlet orifices at the opposite end of said chamber arranged in a pattern occupying substantially the entire cross section of said chamber above said collection trough, means for supplying the oil-continuous liquid to be treated to said discharge orifices to discharge simultaneously therefrom, and means for collecting and withdrawing from the container the liquid entering said outlet orifices; a plurality of electrode sets dividing the length of said chamher into settling spaces and interelectrode treating spaces, each electrode set including two upright foraminous electrodes in said chamber above said trough in the path of flow of said tranquil stream and spaced horizontally from each other to define one of said interelectrode treating spaces therebetween, the width of said settling spaces measured horizontally being substantially greater than the horizontal width of said interelectrode treating space formed by the electrodes of each set, said tranquil stream of oilcontinuous material flowing successively through an interelectrode treating space, a settling space, another interelectrode treating space and so on in its flow from end to end of said chamber between said upright banks of discharge and outlet orifices; means for discharging into said tranquil oil-continuous stream droplets of a wash medium of greater density and electrical conductivity than the material of such stream, said last-named means including pipe means providing orifices above the settling spaces between said sets and means for delivering to said pipe means a stream of such wash medium; means electrically connected to said electrodes establishing a highvoltage electric field in said treating space, material settling from said tranquil stream collecting in said collection trough, the remaining tranquil stream entering said outlet orifices; and a pipe withdrawing material from said collection trough.

4. An electric emulsion treater including: a grounded container providing a chamber closed from the atmosphere; a high voltage electrode in said chamber; means for electrically insulating said electrode from said container and supplying thereto a high-voltage potential, said means including a bushing extending through a wall of said container, a conductor in said bushing and a switch contact within said container connected to said conductor, a switch arm electrically connected to said electrode and means for moving said switch arm from a closed electrode-energizing position in engagement with said switch contact to an open position in which said switch arm disengages said contact; a rod and means for mounting same to move into and from operative and electrical engagement with said switch arm to move the latter from said 9 closed electrode-energizing position to said open position; means for electrically grounding said rod; and means for moving said rod from a position outside said container.

5. An electric treater as defined in claim 4 including means biasing said switch arm toward said closed electrode-energizing position, said rod normally being spaced from said switch arm.

6. An electric treater as defined in claim 4 including a high-voltage source connected to said conductor of said bushing and means for limiting the current flow to said electrode when said rod engages said switch arm and before said arm separates from said switch contact.

References Cited in the file of this patent UNITED STATES PATENTS Harris Jan. 31, 1922 Meredith Nov. 24, 1925 Fisher Feb. 4, 1936 Adams et al. June 17, 1941 McDonald June 5, 1945 De Wit June 15, 1954 Packie Feb. 11, 1958 Stengel Oct. 7, 1958 Turner July 14, 1959 Turner Jan. 15, 1963 Carswell et a1 Jan. 22, 1963

Claims

1. A METHOD OF ELECTRICALLY TREATING AN OIL CONTAINING DISPERSED PARTICLES TO SEPARATE THE LATTER FROM THE OIL, WHICH METHOD INCLUDES THE STEPS OF : ESTABLISHING HIGHVOLTAGE ELECTRIC FIELDS IN TREATING SPACES SPACED FROM EACH OTHER ALONG THE LENGTH OF A HORIZONTALLY ELONGATED PASSAGE, THERE BEING SETTING ZONES BETWEEN SUCH TREATING SPACES, THE HORIZONTAL WIDTH OF EACH SETTING ZONE GREATLY EXCEEDING THE HORIZONTAL WIDTH OF EACH TREATING SPACE; FORWARDLY FLOWING A STREAM OF SUCH OIL HORIZONTALLY ALONG SAID ELEONGATED PASSAGE AND SUCCESSIVELY THROUGH THE TREATING SPACES AND THE INTERVENING SETTING ZONES; DISCHARGING INTO EACH OF SAID SETTING ZONES DIRECTLY INTO THE OIL THEREIN ADDED PARTICLES OF A WASH MEDIUM LARGER IN SIZE THAN SAID DISPERSED PARTICLES AND OF HIGHER ELECTRICAL CONDUCTIVITY AND DENSITY THAN SAID OIL, THE ADDED PARTICLES OF WASH MEDIUM DROPPING BY GRAVITY TRANSVERSELY OF THE OIL STREAM TOWARD THE BOTTOM OF SAID PASSAGE; CONTROLLING THE FORWARD FLOW RATE OF SAID OIL STREAM TO CARRY INTO EACH TREATING SPACE AT LEAST SOME OF THE LARGER PARTICLES OF WASH MEDIUM DISCHARGE INTO A PRECEDING SETTLING ZONE, THE ELECTRIC FIELD IN SUCH TREATING SPACE BEING OF SUFFICIENT INTENSITY TO COALECE PARTICLES OF THE OIL STREAM WITH SUCH RESIDUAL LARGER PARTICLES OF WASH MEDIUM TO FORM COALECED MASSES SETTLING TO THE BOTTOM OF SAID PASSAGE; WITHDRAWING FROM THE BOTTOM OF SAID PASSGE THE COALESCED MASSES AND ANY LARGER PARTICLES SETTING THERETO; AND WITHDRAWING OIL FROM SAID PASSAGE AT A POSITION DOWNSTREAM OF SAID TREATING SPACES.