US2727859A - Apparatus for the electronic treatment of liquids - Google Patents

Description

Dec. 20, 1955 A. s. FREEBORN 2,727,859

APPARATUS FOR THE ELECTRONIC TREATMENT OF LIQUIDS Filed July 18, 1950 2 Sheets-Sheet l 1- ILQO Kg U! IWE N ToR: ALIERT GEORGE FREEBoRu Dec. 20, 1955 A. G. FREEBORN APPARATUS FOR THE ELECTRONIC TREATMENT OF LIQUIDS 2 Sheets-Sheet Filed July 18, 1950 m T N E V N I ALBERT GEoRGi FREEBoRN m AGENT United States Patent APPARATUS FOR THE ELECTRONIC TREATMENT OF LIQUIDS Albert George Freeborn, London, England Application July 18, 1950, Serial No. 174,517 Claims priority, application Great Britain July 29, 1949 2 Claims. (Cl. 204305) This invention relates to improvements in methods and apparatus for subjecting liquids, or liquids with solids in suspension (the term liquid including oils and emulsions and the like) to the effects of an electrical force which necessitates a predetermined electrical potential difference being maintained between two or more electrodes, and where such liquids are brought in contact with these electrodes.

An example of the form of apparatus referred to above is the apparatus described in the present applicants U. S. Patent No. 2,207,583 for the treatment of hard water to prevent scale formation in boilers, pipes, etc. which would otherwise be formed were the water not so treated. However the present invention is not confined to such a limited field of treatment but can be used for other processes where the apparatus used involves electrodes having a constant potential difference between them for subjecting liquids, emulsions and the like to the action of an electrical force.

In such processes it is usual to have two or more electrodes electrically insulated from each other with terminals for the application of the required electrical force, one or more of said electrodes being immersed in the liquid and one other generally being the outer casing of the apparatus which is also in contact with the liquid, such outer casing having inlet and outlet ports for the liquid to flow through, the only passage for the electrical energy to fiow between them being through the liquid being treated, and as the potential ditference between said electrodes is generally of a very low order, the only convenient means of obtaining such required potential difierence in the past has been to measure or calculate the ohmic resistance through the liquid between the electrodes, and adjust the current flowing between them in accordance with Ohms law by means of suitable resistance being inserted in series with the source of electrical energy.

In this known method adjustments of the current are necessitated when the specific resistance of the liquid being treated varies. Also when a very low potential difference, e. g. a few millivolts, or a fraction of a volt, between the electrodes is required considerable areas of electrodes are necessary in order to keep the ohmic resistance between them low enough for a measurable amount of current to be needed.

In the majority of cases with the said known appa- I ratus, the apparatus itself can, under some circumstances, form an electrolytic cell, the apparatus involving metallic electrodes in direct connection with an electrolyte (the liquid), and when such a cell has a low internal resistance considerable current can be set up which may vary with the speed with which the liquid is passing over the electrodes, and which current might interfere with the potential required for the process.

The present invention overcomes all of these disadvantages, and objects of the invention are to ensure:

1. That the potential dilference between the electrodes remains constant for all practical purposes irrespective 2,727,859 Patented Dec. 20, 1955 of the specific electric resistance or conductivity of the liquid or changes in such specific resistance without adjustment of the controlling apparatus. That is to say the apparatus will be self-compensating.

2. That the area of electrode required for any given treatment is very much less than with the aforesaid existing apparatus.

3. That the apparatus keeps the self-generated cur rents down to a minimum.

The method according to the present invention of pretreating a liquid being fed through conduiting to a consuming stage in order to influence by the action of an E. M. F. of a low order, that is to say a small fraction of one volt, constituents in the liquid susceptible to the influence of said very low E. M. F., consists in subjecting the liquid to the action of a constant electrical force by passing electrical energy through the liquid across electrodes located in intimate physical relationship with the liquid, and maintaining the potential difference across the electrodes constant by connecting them to the source of low E. M. F. and a resistance in parallel with, and

relatively small in relation to, the resistance through the liquid between the electrodes, the electrical resistance between the electrodes being relatively high.

Further, the method according to one form of the present invention of pre-treating a liquid being fed through conduiting to a consuming stage in order to neutralise by the action of an E. M. F. of a few millivolts constituents in the liquid susceptible to the influence of said very low E. M. F. without changing the normal function of the liquid, consists in subjecting the liquid to the action of a constant electrical force by passing electrical energy through the liquid across electrodes located in intimate physical relationship with the liquid the electrical resistance between the electrodes being relatively high, and maintaining the potential difference across the electrodes constant by connecting them to the source of very low E. M. F. and a resistance in parallel with, and exceedingly very small in relation to, the resistance through the liquid between the electrodes.

The apparatus of the present invention is broadly characterised by the provision of a shunt resistance of known value across the electrodes of the unit by which are produced relatively high and low resistances in parallel, the difference between these resistances being such that their total resistance will not change appreciably if the internal resistance of the unit or cell varies over quite a large range, such variation being due to variations in the liquid or the speed of the liquid past the electrodes.

in pursuance of the foregoing it should be understood that providing the resistance of the unit and that of the shunted resistance are sufliciently far apart, the resistance of the shunted resistance will for all practical purposes be equal to the resistance of the two in parallel. Thus all that will be necessary to maintain a constant potential difierence across the liquid irrespective of considerable change in the specific resistance of the liquid will be to apply across the shunted resistance a suflicient current of electrical energy to maintain the required potential difference across the ends of the shunted resistance.

The invention is further characterised in that the apparates for subjecting liquids to the action of a very low electrical force, e. g. in the neighbourhood of a small fraction of one volt, comprises a hollow body forming one electrode and shaped for insertion in a pipe line and an internal electrode or electrodes, the said hollow body being constituted by two identical end parts detachably connected together to form a symmetrical hollow body, the internal electrode, or electrodes, being secured detachably in position at the junction plane or planes of the said end parts.

The said apparatus for supporting one internal electrode can comprise two identical substantially half-ellipsoidal bsaypaas with opposeanairges' 'at their larger diameter ends by which they are bolted "together with an interposed disc-like or. annular. electrode insulated fromdirect electricallcont'act with the end parts, thefouter ends of said body parts being bossed or flanged for. connection to the pipe line, and terminals on the perimcters of the electrode and at least .oneof the end body parts for connection to the source of low E. M. F.

A single metal plate-like perforated disc can comprise the internal electrode, or an annulus with a plurality of inwardly directed integral or attached limbs or a ring carrying arr-inwardly directed .arm'or arms for one or more ball-like metallic. electrode. elements. pair or more of the internal'electrodes can be provided by [providing one or more distance piece sleeves or tubes between them with appropriateinsulation.

In carrying one form of the invention into practice, the-plant consists of two parts: (1) The unit which may be positioned'in a pipeline through which the liquid being'treated flows and which may consist of an outer casing, which is one'of the aforesaid electrodes, to contain theliquidhavinginlet and outlet ports for connection to the pipe line and. through which the liquid enters and leaves togetherwith one or more electrodes electrically insulatedfrorn-the outer casing which are immersed in the liquid, and when more than one such electrode is beingused they may also be electrically insulated from each other, the outer casing and the immersed electrode all having exterior terminals for the convenient applicationof the electrical force required; the construction being such that the only path by which. electrical energy can flow between the electrodes internally is through the liquidbeing treated. (2) The source of electrical energy together with. the necessary apparatus which controls the how of electrical energy in accordance with the special requirements of the process.

Thisinvention alsocalls for apparatus which has two parts: (1) a hollow body, or tubular cell body which is adapted to be inserted in a pipe line through which the liquid passes and in which it receives treatment, and (2) the. controlling apparatus which applies the electrical encrgy and controls it.

The casing or shell of the cell can be of cylindrical form with end walls adapted for connection in-the pipe line and act as one electrode, for which'purpose it would be provided with an external terminal. The internal electrode, however, can be of much simpler construction, and by way of example could consist of a plate extending right across the section of the outer casing but electrically insulated from it by means of rubber gaskets for instance, and having a multiplicity of holes drilled through it through which the liquid can pass, the terminal for this plate being brought outside for the application of the electrical force. The only consideration regarding size of the perforated electrode is that it must be of such area that a sutficient number of holes or orifices can be made in it to pass the requisite amount of liquid. It is also essential that there must be a relatively high electric resistance through the liquid between the electrodes.

The above describes a type of electrode which might be used if it is desirable to break the liquid up into fine streams. If this is not essential this internal electrode can be even simpler still and might consist of a ball centrally situated Within the outer casing and. supported by a post which passes through the wall of'the outer casing through an insulating bush of watertight construction.

This cell of relatively high resistance is shunted either internally or externally with a resistance of known and relatively low resistance which can take the form of a short piece of resistance wire or any other convenient form.

There are then two resistances in parallel, one relatively high. (the cell) and one relatively low (the shunting.

resistance) If desired a.

Providing the relative difierence between these two resrsta'ncesis considerable the total resistance "of 'the'two resistances in parallel will not appreciably change if the internal resistance of the cell varies very considerably.

By way of example drawings are appended hereto illustrating various forms of the apparatus, and wherein:

Figure l is a sectional elevation though a simple form of th'e'appa'ratu's e; g. suitablefor domestic main supply lines and for like purposes;

Figure 2 is an exploded perspective view of the apparatus shown in Figure 1.

Figure 3 is asectional elevation showing how the apparatus of Figure 1 can be adapted to receive two or more internal electrodes.

Figure 4 is a sectional elevation of a further embodirnent suitable for large capacity work in which the configuration oi the outer or tubular electrode is such that it will obviate pockets in which air can collect if the unit'is inja horizontal position, and

Figure 5 is an inner'end elevation view of one of the body .parts of the outer electrode of Figure, 4.

Referring to" the drawings, in Figures 1 and 2, the unit ill'ustrated has an outer body in itself forming an electrode and constituted by a bronze or other suitable pairof'symmetrical substantially half-ellipsoidal hollow partsl and 2 .with flanges .121 and 2a respectively between .whichisgripped the co-operating electrode 3 in the form ofa circular plate of Monel metal or other suitable metal or allot, the electrode 3 being insulated from jtheqelectrod'es 1 and 2 by rubber gaskets, or, as shown, a single rubber annular gasket 4 moulded about the periphery of'theelectrode 3, this electrode and the rubber' gasket being formed.with'diametrically opposed lugs 3a and 4a, Fig. 2, respectively, the rubber lugs seating in-diametrically, opposed channels 5 in the flanges 121 and 251 so that the electrode 3 is fully insulated from the electrode constituting, the hollow body part formed by the- electrodes 1 and 2; Hexagonal or other suitable form of hollow bosses 6 are formed on the outer end of the electrodes 1' and 2 for connection to the appropriate pipe line. a

The electrode 3 is formed with a plurality of apertures 7 so astobreak-up the bodyof water into a plurality of streams during its passage through the unit, and the number and'total effective area of these apertures is such as .not to impede-the flow of fluid along the conduitingin which the unitis fitted.

Oneof the lugs 3a, or, as shown, both of them, is, or are, adapted to serveas terminal members for which purpose -each,=or one of them, receives-a terminal screw 8. Actually, convenient to' providetwo in orderthat there is normally always afforded a-reasonably easy point of connection for a lead, this facilitating testing requiring the temporary connection ofa lead to the electrode. Insulation washers 9 are interposed-between the-nuts 10 and the appropriate flange 1a or 2a, and on one face each rubber lug 4a is formed with-a -boss-4bengaging in an aperture in the appropriate'flange 1a or 2:1 so as to insulate the terminal stud from theflange.

One of .the flanges 1a 'or 2a is also fitted with a terminal screw 11 and by meanstof the selected terminal screw 8' and terminal-screw 11 the unit is connected by leads 12 and" 13 to the-source of very low E. M. F. so that an arrangement similar to an electrolytic cell is provided in which theequivalent of the electrolyte is the liquid passing throughthe'unit, although actually the action taking place in the cell is not the normally accepted electrolyte in'which onejofthe electrodes would acquire a deposit ofsalt's, no such deposit occurring with the present device, although'withsointi liquids e. g. in boilers, and boiler lines, where de scaling takes place by reason of theiactior'fset upfbyftheunit 'thescaleand scale forming constituehts willb'tlirowndown as sludge and particles one.:terminal screw is sutficient, but it is a ms 1 2 and 3 arc ,a ymmttital Will] WW! other and each in themselves is of symmetrical configuration, but in the embodiment shown in Figures 4 and 5 whilst the members 1 and 2 are symmetrical with respect to each other each of themselves is of asymmetrical configuration by making their cylindrical outer ends 16 eccentric in relation to their annular flanged inner ends, such outer ends being flanged or otherwise adapted for connection to the appropriate line. The cylindrical outer end of each of the said body parts merges in a substantially flared curvilinear manner into the flange 1a or 2a so that a biased bulbous portion 17 is provided with each member 1 and 2. The advantage of this configuration of outer electrode is that the combined bulbous portion 17 can, in the event of the unit being arranged horizontally form the base thereof, and the part cylindrical upper part which is parallel with the axis of the cylindrical end part 16 will enable a free flow of liquid to pass through the unit without pockets being formed therein in which air and gases can collect, this collection or" air or gases having been found in the past to cause difl'iculties in pipe lines.

The electrode 3 in this embodiment is shown as separated by two separate rubber gaskets 18 the perimeters of which are shaped so as to extend over the terminal pin receiving the lug 3a of the electrode 3.

The parts 1 and 2 with the interposed electrode 3, and likewise the parts 1 and 14 and 14 and 2 of Figure 3 can be secured together by any suitable means, e. g. bolts passed therethrough, or as shown studs passed through co-axial holes in the flanges 1a and 2a and threaded into one of the set of holes.

The E. M. F. applied to the electrodes is such that the potential difference across the electrode 3 and the electrodes 1 and 2 is of an exceedingly low order, i. e. in the range of from 0.1 to 0.3 millivolt.

An important feature of the present invention is the provision across the leads 12 and 13 of a resistance 19, so that the whole unit or cell is shunted with a resistance of which is relatively low when compared with the resistance through the fluid in the pipe unit between the electrodes 3 and the outer casing 1 and 2. This resistance is of an order not higher than 1 ohm.

For example, if the unit or cell is constructed in the manner shown in Figures 1 and 2, with water such as the average water in London which has an electrical resistance of approximately 2,000 ohms per centimeter cube, the cell has an internal resistance of 1,000 ohms and such cell is shunted'with a resistance having a value of 1 ohm the total resistance will be .999 ohm. Should the water increase or decrease in resistance fourfold the resultant total resistances will then be .9997 and .996 ohm respectively. Thus the resultant total resistances are all so close to one another that for all practical purposes they are the same. In this case all that would be necessary to ensure that a constant predetermined potential difference is maintained between the anode and cathode of the cell, would be to suitably regulate, e. g. by a variable resistor or potentiometer 20 and a highly sensitive meter 21, the current of electrical energy, supplied by a suitable source 22, such as a dry cell, flowing through the total resistance to what would be necessary to cause the required potential difference between the terminals of the total resistance. As an example, assume that the total resistance is 1 ohm and that the required potential difference is 2 millivolts, then a current of 2 milliamps flowing through the total resistance will maintain a steady potential difierence of 2 millivolts between the anode and cathode of the cell when vastly differing waters are flowing through the cell. The same principle can be applied to a cell having two or more anodes.

Should flat D. C. electrical energy be adopted, a dry cell would be a convenient source of supply with the necessary series resistance in circuit to adjust the current tltll 1W [Mm/711mm W, A. 6 (lift/[MAC can equally Well be used with such apparatus, attention being given to impedance should periodicity make this necessary. Should it be desired to use such apparatus with high frequency current particular attention must be given to this latter point.

According to the above example, if the fixed resistance is about 1 ohm and a standard dry cell is used as a means for supplying electric treating energy having a voltage of 1.5 volts, it is necessary to drop this voltage by the variable resistance 21 to the required treating voltage of 2 millivolts. Accordingly, the resistance 21 must have a value considerably larger than the resistance 19 shunted across the treating electrodes. From this it follows further that, in providing a desired treating voltage, the current indicated by the meter 21 or the value of the resistance 20 must be such as to produce a voltage drop equal to said treating voltage across the fixed resistance 19, substantially independently of the electric resistance of the liquid between the treating electrodes. In other words, the treating voltage can now be adjusted in advance or the meter 21 or variable resistance 20 calibrated in terms of treating voltage, independently of the type of liquid to be treated. This not only greatly simplifies the manufacture and operation of the device, but insures positive and optimum treating conditions at all times and under all circumstances.

Cases in which the process makes it desirable for the fluid to be subjected to the eifects of two or more diiferent potentials whilst passing through the cell, or cases in which it is desirable to subject the liquid to two or more difierent forms of electrical energy such as flat D. C. and high frequency A. C. or pulsating D. C., can easily be arranged by having two or more anodes disposed inside the cathode, electrically insulated from the cathode and from each other and so arranged that the electrical resistance through the liquid is high in each case. The above mentioned shunting resistances and the necessary source of energy being applied as before in each case.

Whilst the foregoing has described the application of this invention to a unit which fits in a pipe line through which the liquid to be treated is flowing, it can equally well be applied to an open trough or any form of apparatus through which liquid can flow, and in addition to its use for the treatment of hard Water to prevent scale, it can be used for other processes which call for a'liquid to be subjected to the elfects of a low E. M. F., for instance, to treat paper pulp in liquid form to give added strength to the resultant paper, to treat vegetable extracts or pulp in liquid form to improve their flavours and keeping qualities to stabilise or break down emulsions etc.

In constructing the cell mentioned above that would be used in a pipe line, the high resistance necessary between the anode or anodes and the cathode can be brought about in various ways. For instance, by sizing and spacing the various electrodes so that the direct passage of the electrical energy through the liquid between the electrodes is in itself sufliciently high for the required purpose, or if more convenient, the internal surface of the cathode which is in contact with the fluid can be partially coated with a high resistance medium, for instance, vitreous enamel.

The cell may be constructed substantially in the manner described with reference to Figure 3, and have its internal surface insulated. It would then have two electrodes of exactly similar construction inside it and immersed in the liquid, insulated from each other and with terminals brought outside. These immersed electrodes which can be identical perforated discs spaced apart by an intermediate or distance piece cylindrical wall section of the cell and insulated by annular insulation layers betive to the flow of the liquid. One could then be'used as the-anode and the other as the cathode. As they are in al-l respects similar there would be no chemical electrical-potential difference between them and as they are both 'subject to the same rate of flow of the same liquid this will not afiect them either, .One of them could be connectedelectrically tothe outer'casing of the cell by a-lead l5-if it isnecessaryto stabilise one pole of the electrical force with the outer casing which may be ea'rthed. Sucha cell is 'illustr'ated by Figure 3.

In.- the aboveconnexion, component parts of the cell used for the treatment of liquids have been spoken of as electrodes. They are still to be considered as such even though they may be coated, on'the'faces of them incontact with theliquid, with an insulating medium such as vitreous enamel, thus, in the case of an electrode 3,

leaving only the metal edges of the holes 7 exposed for contact'with the water, i. e. obtaining the partial insulating coating foran electrode. 7

In apparatus such as is generally described above, mention has been made ofthe current of electrical energy actually flowing from one electrode to another through.

the fluid. This is because it has" been by such means that the most convenient method has been found to maintain. the electrode immersed in the liquid or anode at a potential diilerence-relative to'the other electrode.

It will be. appreciated from the foregoing that the effective surface area of electrodes can be'con-siderably less than with existing apparatus in use,-because each electrode only, needs that area which the process requires to treat the amountfof liquid which the unit is designed to handle, without having to add to this area solely for the purpose of keeping the ohmic resistance between the electrodes low. 1 I

The apparatus may include fixed or adjustable means to regulate the'rate of liquid flow through one or more of the electrodes so as to establish a uniform flow through all'electr'odes, or at least when two or more perforated treating voltage of a value'substantially-belowthe limit Where electrolysis occurs and means for passinga liquid stream to be treated in exposedcontact with 'said elecrodes, to condition the dissolvedconstituents by the electric force acting thereon and to-thereby affect their subsequent physical and/or chemical behavior; means for supplying electric energy having a-voltage considerably in excess of said treating voltage, a first variable resistance connected in series with-said source and said electrodes, and a further fixed resistance having a value equal to a small fraction of said firstresistance and shunted across said electrodes, said resistances having a total value to cause the current therethrough from said source to be a considerable multipleofthe current between-said electrodes required to produce a voltage drop therebetween equal to said treating voltage for a given liquid to be treated, whereby said fixed resistance producesa constant voltage drop equal to said treating voltage and substantially independent of the electric conductivity of said liquid.

2. In apparatus for electrically treating liquids containing dissolved ionic constituents comprising a pair of spaced electrodes having applied thereto a treating voltage of from a few millivolts to fractions of amillivolt and means for passing a liquid stream to be treated in exposed contact with said electrodes, to condition the dissolved constituents by the electric force acting thereon and to thereby affect their'subsequent physical and/or chemical behavior; a dry cell for supplying electric energy having a voltage which is considerably in'excess of said treating voltage, a firstvariable' resistance connected in" series with said cell and, said electrodes, and'a further fixed resistance of about one ohrn' which is a value equal to a small fractionof said first resistance and shunted across said electrodes, said resistances having a 'total'value to cause the current there'through from-said 'source to be a considerable multiple-of the'current between'said ele'ctrodes reelectrodes are employed, through all-of them, and e. g. a

venturi' device or devices fixed or adjustable, can beincorpo'rated in the apparatus for this purpose. Alterna tively, or in addition, when using reticulated electrodessuchas 3, plugs or other suitable means can be provided forclosing any desired number of perforations, and where necessary'these plugs can be di-electric members so as tobe'inert.

I claim:

1. In apparatus for electrically treating liquids containingdissolved ionic constituents comprising a pair of spaced electrodes having applied thereto a predetermined quired to produce a voltage drop therebetween equal to said treating voltage for agiven'liquid' to be treated, whereby said fixed resistance produces a' constant voltage drop equal-to said treating voltage andsubstantially independent of the electric conductivitybfsaid'liquid.

References Cited in the file ofthis patent UNITED STATES PATENTS

Claims (1)

1. IN APPARATUS FOR ELECTRICALLY TREATING LIQUIDS CONTAINING DISSOLVED IONIC CONSITUENTS COMPRISING A PAIR OF SPACED ELECTRODES HAVING APPLIED THERETO A PREDETERMINED TREATING VOLTAGE OF A VALUE SUBSTANTIALLY BELOW THE LIMIT WHERE ELECTROLYSIS OCCURS AND MEANS FOR PASSING A LIQUID STREAM TO BE TREATED IN EXPOSED CONTACT WITH SAID ELECTRODES, TO CONDITION THE DISSOLVED CONSTITUENTS BY THE ELECTRIC FORCE ACTING THEREON AND TO THEREBY AFFECT THEIR SUBSEQUENT PHYSICAL AND/OR CHEMICAL BEHAVOR; MEANS FOR SUPPLYING ELECTRIC ENERGY HAVING A VOLTAGE CONSIDERABLY IN EXCESS OF SAID TREATING VOLTAGE, A FIRST VARIABLE RESISANCE CONNECTED IN SERIES WITH SAID SOURCE AND SAID ELECTRODES, AND A FURTHER FIXED RESISTANCE HAVING A VALUE EQUAL TO A SMALL FRACTION OF SAID FIRST RESISTANCE AND SHUNTED ACROSS SAID ELECTRODES, SAID RESISTANCE HAVING A TOTAL VALUE TO CAUSE THE CURRENT THERETHROUGH FROM SAID SOURCE TO BE A CONSIDERABLE MULTIPLE OF THE CURRENT BETWEEN SAID ELECTRODES REQUIRED TO PRODUCE A VOLTAGE DROP THEREBETWEEN EQUAL TO SAID TREATING VOLTAGE FOR A GIVEN LIQUID TO BE TREATED, WHEREBY SAID FIXED RESISTANCE PRODUCES A CONSTANT VOLTAGE DROP EQUAL TO SAID TREATING VOLTAGE AND SUBSTA

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