Fluid treatment system employing electrically reconfigurable electrode arrangement

Page 1 — bibliographic record

Page 2

Drawing sheet — no readable text.

Page 3

Drawing sheet — no readable text.

Page 4

Drawing sheet — no readable text.

Page 5

Drawing sheet — no readable text.

Page 6

Drawing sheet — no readable text.

Page 7

Drawing sheet — no readable text.

Page 8

Drawing sheet — no readable text.

Page 9

Drawing sheet — no readable text.

Page 10

Drawing sheet — no readable text.

Page 11

Drawing sheet — no readable text.

Page 12

INITIALIZE

STARTUP

MONITOR w ow no wa t s a wo w t s al u s co V s M ow

CURRENT

NO THRESHOLD

EXCEEDED

YES

RECONFICURE ( 152

ELECTRODES

CURRENT

THRESHOLD

EXCEEDED

YES f 64 7 Recovircur RECONFIGURE ELECTRODES ELECTRODES

MONITOR MONITOR CURRENT CURRENT

THRESHOLD YES THRESHOLD EXCEEDED EXCEEDED

YES

FIG. 1 1. 70

Page 13

control circuits of both systems are relatively complex.

FLUID TREATMENT SYSTEM EMPLOYING Because the Paschakarnis et al. circuit introduces an ELECTRICALLY RECONFIGURABLE additional resistance into the current path, it is also ELECTRODE ARRANGEMENT relatively inefficient. The Saito circuit, in turn, disad

FIELD OF THE ENVENTION

vantageously requires reference measurements to be made for subsequent use in controlling the voltage ap

This invention relates generally to electrolytic fluid plied to the electrodes.

treatment systems and, more particularly, to electrode An alternative method of handling variations in arrangements used in such systems. water conductivity is to ensure that the system is ex 10 posed to a relatively constant load resistance, regardless

BACKGROUND OF THE INVENTION of variations in water resistivity. U.S. Pat. No. 4,769,119 Electrolytic fluid treatment systems are widely used (Grundler) discloses a water ionizing device, including to, for example, remove impurities and contaminants several electrodes, that employs this approach. If the from fluids. In such systems, the fluid to be treated is resistivity of the water being ionized is relatively low, a passed between one or more pairs of electrodes. An 15 relatively high resistance is introduced in series with the electric potential applied to the electrodes establishes an electrodes. On the other hand, if the water's resistivity electric current between the electrodes. As a result, is relatively high, a relatively low resistance is intro impurities in the fluid migrate and adhere to the elec duced in series with the electrodes. In either case, by trodes, biological materials in the fluid are killed, and 20 keeping the system's total resistive load constant, a the fluid's chemical composition may be altered. constant current flow is maintained between the elec One fluid that is commonly processed by electrolytic trodes.

fluid treatment systems is water. The electrolytic treat U.S. Pat. No. 4,986,906 (Dadisman) describes another ment of water is, however, complicated by the widely variation of this approach. The Dadisman water purifi varying water characteristics encountered from one cation system includes a constant current control circuit water source to another. In that regard, the resistivity of 25 water, which is inversely proportional to conductivity, in which changes in water resistance cause opposing changes in the effective resistance of a field-effect tran commonly varies over a range extending from 30 to sistor (FET) included in the circuit. These changes in 1400 ohm-meter. Such resistivity variations may signifi FET resistance offset the changes in water resistance, cantly alter the performance of an electrolytic filter allowing the current to be kept substantially constant. system. 30

More particularly, the interelectrode resistance is tain limitations. MoreDadisman

The Grundler and systems also have cer particularly, the Grundler and dependent upon the resistivity of the water flowing Dadisman circuits both increase circuit resistance to between the electrodes. With a fixed electric potential offset decreases in water resistance. As a result, energy applied to the electrodes, current flow between the electrodes will vary in inverse proportion to the water's 35 is dissipated in circuit components rather than being resistance. If water resistivity is relatively high, the used to filter water, making the circuit relatively ineffi current may be too low to achieve the desired treatment are cient. In addition, the Grundler and Dadisman circuits of the water. On the other hand, if water resistivity is also both relatively complex. relatively low, the current may be so high as to damage Yet another technique proposed to handle variations or otherwise decrease the life of system components. in water resistivity is described in U.S. Pat. No. A variety of different systems have been developed 3,691,050 (Sayre). The Sayre water treatment cell in that attempt to accommodate such variations in water cludes electrodes whose separation is mechanically resistivity. For example, electronic control circuits adjustable. If the cell is to be used with water having a have been designed to allow water purification and ion relatively high resistivity, the operator physically ad generation systems to maintain constant current flows, 45 justs the electrodes so that they are closer together. substantially independent of variations in water resistiv Alternatively, if the system is to be used with water ity. having a relatively low resistivity, the operator adjusts In that regard, U.S. Pat. No. 4,119,520 (Paschakarnis the electrodes so that they are more widely spaced. In et al.) discloses a water purification unit that includes either event, the interelectrode resistance is kept uni such a current control circuit. The current to be con form, ensuring a constant current flow. trolled flows through a resistor, as well as between the As will be appreciated, the Sayre system has several electrodes. A differential amplifier and transistor coop shortcomings. First, the operator is required to make eratively control the current by keeping the voltage independent assessments of the water's resistivity. In drop across the resistor equal to the reference potential addition, the system is relatively complicated and the across a diode. As a result, the current flowing between 55 necessary adjustments are relatively time consuming to the electrodes is kept constant. perform. Finally, because the system does not automati Similarly, U.S. Pat. No. 5,055,170 (Saito) discloses an cally respond to variations in water resistivity, it may ionic water generator that accounts for variations in fail to achieve the desired regulation in many instances. water resistivity. The Saito system employs a central As will be appreciated from the foregoing remarks, it processing unit that calculates the appropriate voltage would be desirable to provide a electrolytic filter sys to be applied to the electrodes for the water being pro tem that is substantially free from the influence of water cessed. This voltage is computed by multiplying some resistivity variations, while remaining relatively effi voltage corresponding to the desired ion concentration cient, simple, and easy to operate.

by a factor equal to the resistance of the water actually SUMMARY OF THE INVENTION being processed divided by the resistance of some refer 65 ence water. In accordance with this invention, an electrolytic As will be appreciated, the Paschakarnis et al. and fluid treatment system is described for treating a fluid. Saito systems exhibit several shortcomings. First, the The filter system includes a plurality of electrodes and a

Page 14

support structure for physically supporting the elec FIG. 6 is a flow chart depicting the operation of the trodes. An electrical reconfiguration circuit is included control circuit of FIG. 4;

for providing electrically reconfigurable connections to FIG. 7 is a graph depicting some potential current the plurality of electrodes. The system also includes a adjustments made by the control circuit of FIG. 4; sensor for producing an output representative of the FIG. 8 is another graph depicting various modes of resistivity of the fluid. The reconfiguration circuit pro operation of the control circuit of FIG. 4 as a function vides the electrically reconfigurable connections to the of water resistivity;

plurality of electrodes in response to the sensor's out FIG. 9 is an illustration of an alternative mechanical put. arrangement and construction of the electrodes of FIG. In accordance with an additional aspect of this inven 10 3;

tion, the reconfiguration circuit is for electrically con FIG. 10 is a schematic diagram of the electrodes necting different electrodes for use as anodes and cath included in the arrangement of FIG.9, with a switching odes when the sensor output is representative of a fluid circuit used to alter the connection of the electrodes; resistivity above some threshold level. The circuit may and reconfigure the connections of selected electrodes for 15 FIG. 11 is a flow chart depicting the operation of the use as charged and uncharged electrodes and for recon control circuit to regulate the electrode connections of figuring the connections of charged electrodes for use FIG. 10.

as anodes and cathodes when the output is representa tive of a fluid resistivity below some threshold. The DETAILED DESCRIPTION OF THE circuit may also reconfigure the connections of eight 20 PREFERRED EMBODIMENT adjacent electrodes for use as an anode, neutral elec Referring now to FIG. 1, a fluid system 10 con trode, neutral electrode, neutral electrode, cathode, structed in accordance with the invention is depicted. neutral electrode, neutral electrode, and neutral elec Fluid system 10 includes a fluid source 12 that provides trode, respectively, when the output is representative of fluid to a supplied environment 14 via an electrolytic a fluid resistivity below some threshold. 25 fluid treatment system, such as filter system 16. As will In accordance with another aspect of the invention, a method is disclosed of electrolytically treating a fluid, be described in greater detail below, the electrolytic filter system 16 is designed to remove contaminants and that is responsive to variations in the resistivity of the impurities fluid. The method includes the steps of evaluating the manner thatfrom is the fluid in an efficient and effective not adversely impacted by variations in resistivity of the fluid to be treated and electrically 30 fluid's resistivity.

connecting a plurality of electrodes together in a partic theBefore ular configuration responsive to the evaluated resistiv system 10 discussingin greater the construction and operation of detail, the physics involved will be ity of the fluid. briefly reviewed. In that regard, conventional electro In accordance with an additional aspect of this inven lytic filter systems pass electric current between at least tion, an electrolytic filter system for filtering a fluid is 35 one pair of electrodes to effect the desired filtration of disclosed. In one arrangement, the system includes a fluids located between the electrodes. The ability of the plurality of electrodes physically supported relative to system to cause impurities to migrate to the electrodes, one another and a circuit for electrically connecting the kill biological material, and alter the chemical composi electrodes to define one or more active electrodes whose effective separation is dependent upon the resis of tion of the fluids depends, in part, upon the magnitude the current flow between the electrodes.

tivity of the fluid. In another arrangement, the system Assuming that a fixed voltage V is applied across two includes a plurality of electrodes, each of which in electrodes, the magnitude of the current I flowing be cludes a plurality of individual elements, and a circuit tween the electrodes varies substantially in accordance for electrically connecting the electrode elements to define one or more active electrodes whose effective 45 with the expression:

area is dependent upon the resistivity of the fluid. I-V/R (1)

BRIEF DESCRIPTION OF THE DRAWINGS

where R is the resistance of the fluid between the elec

The foregoing aspects and many of the attendant trodes. The resistance R of the fluid can be determined advantages of this invention will become more readily 50 in accordance with the expression:

appreciated as the same becomes better understood by reference to the following detailed description, when R=pL/A (2) taken in conjunction with the accompanying drawings, wherein: where p is the resistivity of the fluid, L is the separation FIG. 1 is a block diagram of an electrolytic filter 55 of the two electrodes, and A is the cross-sectional area system constructed in accordance with the present in of the fluid path between the electrodes. The resistivity vention; p, in turn, varies in accordance with the expression: FIG. 2 is an illustration of an electrolytic cell in cluded in the filter system of FIG. 1 and employing a p=p1+a(T-To)) (3) plurality of electrically reconfigurable electrodes;

FIG. 3 is a perspective view of an electrode assembly where po is the resistivity of the fluid at some tempera included in the electrolytic cell of FIG. 2, with parts ture To, T is the actual temperature of the fluid and a is shown in exploded relationship; a temperature coefficient. As a result, the resistivity FIG. 4 is a block diagram of a control circuit included and, hence, resistance of the fluid defining the current in the filter system of FIG. 1; 65 path between electrodes changes in response to both FIG. 5 is a schematic diagram of the electrodes in fluid and temperature fluctuations.

cluded in the assembly of FIG.3 and a switching circuit With a fixed voltage applied between the two elec used to alter the connection of the electrodes; trodes, the magnitude of the current I flowing therebe

Page 15

tween thus depends upon the fluid resistance R. As from the channel piece 40 and exhibits a tapered cross noted previously, the resistivity p (and its reciprocal, section. A semicircular opening 54, hidden in FIGS. 2 conductivity o) of the fluid may vary considerably with and 3, is provided at the end of inlet piece 52 to form time. These variations may be attributable to differences one half of a fluid inlet.

in the composition of the fluid as well as its temperature. The sides 44 and 46 of the first section 32 of housing In any event, such changes alter the interelectrode resis 26 further include the front portions of wiring conduits tance R and current and potentially impact the filter's 56 and 58, respectively. As illustrated in FIG. 2, con effectiveness. duits 56 and 58 are roughly L shaped, rectangular in As will be described in greater detail below, by alter cross section, and include openings positioned adjacent ing the effective separation L of the electrodes and/or 10 to the opening 48 in panel 42. These openings are pro the cross-sectional area A of the fluid flow path, these vided in a longitudinally staggered configuration that variations in resistivity can be accommodated to main allows the electrical wiring 30 received within the con tain a relatively constant interelectrode resistance and duits to be attached to the various electrodes in a rela current. The embodiments of the electrolytic filter sys tively streamlined fashion described in greater detail tem 16 described below achieve the desired corrections 15 below. The conduits 56 and 58 also terminate in open in these alternative manners. ings adjacent the end of inlet piece 52, from which the Addressing now the construction of the various com electrical wiring 30 extends to the control circuit 20. ponents of system 10 individually, the fluid source 12 The front portions of conduits 56 and 58 extend axi may take any of a variety of forms. Typically, the fluid ally along the open or back side of first section 32, and source 12 will include a fluid supply or reservoir, as are also open to the back of first section 32. As will be well as some arrangement for providing fluid to the described in greater detail below, the front portions are filter system 16 in a controllable and pressurized man closed by backportions provided on section in arrange ner. To that end, the fluid source 12 may include, for ment that makes it easier to form sections 32 and 34, and example, a pump and various valves. to run wiring 30 through conduits 56 and 58. One common example of a fluid source 12 is a munici 25 The second section 34 of housing 26 mirrors the first pal water supply. As will be appreciated, the water section 32, with the exceptions that the opening 48 is available from many such supplies may exhibit widely eliminated and the back, rather than front, portions of varying characteristics. For example, it is not uncom conduits 56 and 58 are provided. More particularly, the mon for the resistivity of water from different munici second section 34 includes a channel piece 60 having a palities to range between 30 to 1400 ohm-meter. 30 panel 62 and two sides 64 and 66. A plurality of elec Like the fluid source 12, supplied environment 14 trode retention grooves 68 are provided on the inside of may take a variety of different forms. Examples of sup panel 62 for receiving the electrodes 28. A tapered inlet plied environments 14 include swimming pools, water piece 70 extends from the channel piece 60 and includes heaters, and drinking water dispensers. In some in a semicircular opening 72, which, in cooperation with stances, although not shown in FIG. , the supplied 35 opening 54, defines a fluid inlet. As shown, the back environment 14 may use the fluid and return it to the portions of conduits 56 and 58 project substantially source 12 for treatment. In other instances, the supplied normal to the sides 64 and 66 and, as noted above, seat environment 14 may represent the ultimate destination against the front portions to form conduits 56 and 58 of the fluid. when the housing 26 is assembled. The heart of fluid system 10 is the electrolytic filter As will be appreciated, the relative size, shape, con system 16. As indicated in FIG. 1, filter system 16 in struction, and materials of the housing 26 can be altered cludes an electrolytic cell 18 and control circuit 20. As as desired. In the currently preferred arrangement, will be described in greater detail below, the electro however, housing 26 is generally rectangular in cross lytic cell 18 processes fluid flowing from source 12 to section and defines an electrode chamber 36 that is the supplied environment 14. The control circuit 20 45 roughly 20.5 centimeters by 5.4 centimeters by 5.1 cen provides electrical energy to the cell 18 in a controlled timeters. The electrode retention grooves 50 and 68 are fashion, allowing cell 18 to effect the desired filtration roughly 0.06 centimeters wide, spaced apart by a dis of the fluid substantially independent of variations in tance of roughly 0.2 centimeters and may extend the full fluid resistivity. length of the electrode plates or be shorter and spaced Reviewing these two primary components of filter 50 apart to support the electrode plates at several points. system 16 in greater detail, as shown in FIG. 2, the The inlet chamber 38 is roughly 8.1 centimeters long electrolytic cell 18 includes an electrode assembly 22 and tapers to a cross section of roughly 4.8 centimeters positioned within a reservoir 24. The electrode assem by 4.5 centimeters. When the first section 32 and second bly 22, which is shown in greater detail in FIG. 3, in section 34 are joined, the semicircular openings 54 and cludes as its primary components a housing 26, a plural 55 72 define a fluid inlet of roughly 23.5 square centime ity of electrodes 28, and electrical wiring 30. The hous ters. Similarly, the open upper end of housing 26, de ing 26 includes a first section 32 and second section 34, fined by the first section 32 and second section 34, pro which cooperatively define an electrode chamber 36 vides a square fluid outlet of roughly 25.6 square centi and inlet chamber 38 therebetween. meters. Sections 32 and 34 are preferably molded from Addressing the construction of the first section 32 of 60 a fluid-impervious plastic, such as polyethylene tere housing 26 in greater detail, the portion of the first phthalate glycol (PETG).

section 32 that defines the electrode chamber 36 in Having reviewed the construction of housing 26, the cludes a channel piece 40 formed by a panel 42 and sides construction of electrodes 28 will now be considered in 44 and 46. A rectangular opening 48 is provided in panel greater detail. As shown in FIG.3, seventeen electrodes 42, midway between its two ends, and a plurality of 65 28 are preferably employed. Each electrode 28 includes longitudinally-extending, electrode retention grooves a substantially rectangular body 78 that is positioned 50 are provided on the inside of panel 42. The first within housing 26 to contact the fluid to be filtered. A section 32 also includes an inlet piece 52, which extends connection tab 80, aligned in the same plane as elec

Page 16

trode body 78, projects from one edge of the electrode fluid impervious plastic such as spun fiber glass (rein body 78. As will be described in greater detail below, forced), acrylonitrite butadiene styrene (ABS). The the connection tabs 80 are designed to extend through reservoir 24 preferably is roughly 0.6 centimeters thick, opening 48 in the first section 32 of housing 26 to allow 100 centimeters long and 40.6 centimeters in diameter. electrical connections to be made to the electrodes 28. The fluid inlet 74 of electrode assembly 22 extends The electrodes 28 are preferably made of an electri through the base of reservoir 24, defining a fluid inlet cally conductive, fluid impervious material, such as a into reservoir 24. A fluid outlet 88 is provided in the top ceramic. The electrode body 78 is roughly 20.3 centi of reservoir 24. As will be appreciated, the reservoir meters by 6.0 centimeters by 0.06 centimeters. Connec may be equipped with a removable cover, in which the tion tab 80 is, for example, roughly 0.6 centimeters by 10 outlet 88 would be provided, allowing access to the 0.5 centimeters by 0.06 centimeters. As shown in FIG. electrode assembly 22.

3, the location of the connection tab 80 between the two Having reviewed the basic construction of electro ends of the electrode body 78 varies from electrode to lytic cell 18, a more detailed discussion of the control electrode.

Reviewing the relative location of the connection control20circuit

circuit will now be provided. As shown in FIG. 4, 20 includes, for example, a DC power tabs in greater detail, the electrodes 28 are separately supply 90, current designated 28a through 28q in FIG. 3. The tabs 80 on controller 98. sensor 92, switching circuit 94, and a electrodes 28a, 28b, 28f 28i, 28i, 28n, and 28g are all Reviewing these components of control circuit 20 spaced roughly 8.3 centimeters from one end of their individually, the DC power supply 90 may be of any respective electrode bodies 78, with the orientation of 20 conventional design electrodes 28a, 28i, and 28g being reversed from that of electrolytic cell 18. Insuitable that for providing energy to the regard, power supply 90 may electrodes 28b, 28f, 28i, and 28n. The tabs 80 on elec trodes 28c, 28g, 28k, and 28o are spaced midway be include a transformer for converting a source of AC tween the two ends of their respective electrode bodies input voltage from one level to another, for example, reduced level. A rectifier circuit may also be included 78. Finally, the tabs 80 on the remaining electrodes 28d, 25 to convert the transformed AC voltage to a suitable DC 28e, 28h, 28.l., 28m, and 28p are spaced roughly 9.2 centi voltage. Finally, a regulation and filtration circuit may meters from one end of their respective electrode bodies be included to ensure that the rectified voltage has the 78, with the orientation of electrodes 28d, 28h, 28, and desired DC characteristics.

28p being reversed from that of electrodes 28e and 28m.

As shown in FIG. 3, the varied location of the electrode 30 The current sensor 92 is coupled to the output of DC tabs 80 effects a staggered alignment that makes it easier power supply 90 to monitor current flow to cell 18. to provide electrical connections to individual elec Current sensor 92 may be, for example, an ammeter capable of producing outputs representative of currents trodes.

With the first section 32 and second section 34 of ranging from one to thirty amperes. The outputs of housing 26 secured together by epoxy or other fasteners 35 current sensor 92 are provided to controller 96, while (not shown), the electrodes 28 are retained in slots 50 the current flowing through current sensor 92 is pro and 68 and the tabs 80 on the various electrodes 28 vided to the electrolytic cell 18 via switching circuit 94. project from the opening 48 in housing 26, allowing The switching circuit 94 is illustrated in greater detail electrical connections to be made thereto. These con in FIG. 5 and is responsible for electrically reconfigur nections are made by the electrical cables 30, which are ing the electrode assembly 22, as described in greater separately identified in FIG.3 as cables 82and84. Cable detail below. Switching circuit 94 may include, for 82 is a stranded wire cable positioned within wiring example, an electromechanical relay 98 with six pairs of conduit 56 and has one end connected to the connection contacts A, B, C, D, E, and F that can be independently tabs 80 of electrodes 28a, 28c, 28e, 28g, 28i, 28k, 28m, opened and closed. The relay 98 receives inputs from 28o, and 28g by, for example, soldering or fastening 45 controller 96, which determines which of the varied hardware (not shown). The other end of cable 82 termi contact pairs A, B, C, D, E, and F will be open and nates at the control circuit 20. Similarly, cable 84 is a closed.

stranded wire cable received within wiring conduit 58. Contact pairs A, B, and C are coupled in parallel and One end of cable 84 is coupled to the connection tabs 80 are used to control which electrodes will be operated as of electrodes 28b, 28d, 28f 28h, 28i, 28.l., 28n, and 28p 50 anodes. As shown in FIG. 5, one side of contact pair A and the other end terminates at the control circuit 20. is coupled to the positive output of power supply 90, Once the housing sections 32 and 36 have been fas while the other side is coupled to electrodes 28e and tened together and the appropriate connections made 28m. Similarly, one side of contact pair B is coupled to between cables 82 and 84 and the various electrodes 28, the positive output of power supply 90, while the other the connection tabs 80, electrical connections between 55 side is coupled to electrodes 28a, 28i, and 28g. In addi cables and tabs, and the opening 48 are enclosed by an tion, one side of contact pair C is coupled to the positive encapsulant, such as an epoxy. As a result, the electrical output of power supply 90, while the other side is cou connections are insulated from one another and pro pled to electrodes 28c, 28g, 28k, and 28o. tected from environmental contaminants. Further, by Contact pairs D, E and F are similarly coupled in closing the opening 48, fluid flow through the electrode parallel and used to control which electrodes will be assembly 22 is confined to a path traversing substan used as cathodes. As shown in FIG. 5, one side of tially the full length of the spaced-apart electrodes 28. contact pair D is coupled to the negative output of As noted previously, the electrode assembly 22 is power supply 90, while the other side is coupled to positioned in, and axially aligned with, reservoir 24. electrodes 28b, 28d, 28f 28h, 28i, 28.l., 28n, and 28p. One The reservoir 24 is employed to store fluid processed by 65 side of contact pair E is coupled to the negative output the electrode assembly 22 before it is provided to the of power supply 90, while the other side is coupled to supplied environment 14. The reservoir 24 may, for electrodes 28c, 28g, 28k, and 28o. Finally, one side of example, be a roughly cylindrical structure made of a contact pair F is coupled to the negative output of

Page 17

power supply 90, while the other side is coupled to acceptable threshold T preprogrammed into ROM 99 electrodes 28e and 28m. or stored in RAM 101 via an operator input. If the Turning now to a discussion of the controller 96, microprocessor determines that the current is above the controller 96 is responsible for directing the desired acceptable threshold T at time t1, the microprocessor 97 electrical reconfiguration of the electrode assembly 22 causes the switching circuit to reconfigure the elec by switching circuit 94, as well as other tasks described trodes at block 108 to achieve a greater active electrode below. In one embodiment, the controller 96 includes a separation. Specifically, relay 98 is actuated to close microprocessor 97, read only memory (ROM) 99 for contacts A, B, and E, while contacts C, D, and F are storing program instructions to be executed by micro open. As a result, electrodes 28a, 28e, 28i, 28m, and 28g processor 97, random access memory (RAM) 101 for 10 are connected as cathodes d and electrodes 28c, 28g, storing data processed by microprocessor 97, and suit 28k, and 28o are connected as anodes. As a result, the able interfaces 103 for allowing microprocessor 97 to distance between adjacent active electrodes in this sec communicate with the remaining components of the ond mode of operation is doubled from its initial value. control circuit 20. As will be appreciated, these compo Likewise, the interelectrode resistance is doubled and nents are each of conventional design. 15 the current, in turn, drops to roughly one-half its previ Having reviewed the basic construction of electro ous value.

lytic cell 18 and control circuit 20, their cooperative As indicated in FIGS. 6 and 7, some time t2, prefera operation to achieve the desired fluid treatment, rela bly on the order of 0.01 seconds after to, the micro tively independent of variations in water resistivity, will processor 97 in controller 96 monitors the current at now be described in conjunction with the flow chart of 20 block 110 and compares the current output of sensor 92 FIG. 6. In that regard, the ROM 99 is preprogrammed to the acceptable threshold Tat block 112. In the event with instructions for use by the microprocessor 97 in that the current still exceeds threshold T, the micro controlling the operation of cell 18, as described in processor 97 causes switching circuit 94 to reconfigure greater detail below. A variety of external inputs I are the electrical connections to the various electrodes at also received from the operator and stored in RAM 101 25 block 114. Specifically, an output is provided to relay 98 to initialize operation of circuit 20, as indicated by block to close contacts B and F, leaving contacts A, C, D and 100. These external inputs, which also may be altered by E open. As a result, electrodes 28a, 28i, and 28q are the operator during use, include the various current connected for use as anodes, while electrodes 28e, and threshold levels and time intervals employed by the 28m are connected for use as cathodes. The separation control circuit 20. 30 between active electrodes is, thus, increased to four At start-up, block 102, the microprocessor 97 pro times its original value in this third mode of operation, vides an output to the DC power supply 90, causing the making the interelectrode resistance four times as high power supply to apply a predetermined voltage of, for and the current roughly one-fourth its original level. example, sixty volts to the switching circuit 94 via cur The current is then monitored again at block 116 and rent sensor 92. This occurs at time to, shown graphically 35 a third, and final, current comparison is performed by in FIG. 7. The controller 96 also provides an output to microprocessor at time t3. Specifically, the output of relay 98, which causes contact pairs A, B, C, and D to current sensor 92 is evaluated at block 118 to determine close and contact pairs E and F to open. As a result, whether the current still exceeds the acceptable thresh electrodes 28a, 28c, 28e, 28g, 28i, 28k, 28m, 28o, and 28q old. If the threshold T is exceeded, the system is shut off are connected to the positive output of supply 90 for use at block 120 to prevent damage to the control circuit as anodes. Electrodes 28b, 28d, 28f 28h, 28i, 28, 28n, due to the high currents provided to the relatively low and 28p, on the other hand, are connected to the nega resistivity water. As will be appreciated, the interval of tive output of supply 90 for use as cathodes. As will be time between to and t3 is kept sufficiently short so that, appreciated, the effective separation between active even with relatively high currents drawn, the circuit anodes and cathodes in this first mode of operation is 45 will not be damaged.

therefore roughly 0.2 centimeters. Another way of protecting the control circuit 20 Next, at block 104, the microprocessor 97 is in from high currents while the desired electrode configu structed to monitor the output of current sensor 92. As ration is being established is to lower the voltage ap will be appreciated, the output of current sensor 92 plied between active electrodes. For example, rather represents the current flowing through cell 18 as a 50 than using the sixty volt "filtering” potential, a lower, whole. If desired, the microprocessor 97 may also di six volt "test” potential can be advantageously applied vide this total current by the number of active electrode across active electrodes during this initial phase of oper pairs to determine the current flowing through each ation. The current flowing between active electrodes electrode for use in future evaluations. This initial deter will then be reduced to one-tenth the level that would mination of current at block 104 is performed at some 55 otherwise be experienced. With threshold T similarly time t1 after to. In the preferred arrangement, t1 will be established at one-tenth the desired current level, the on the order of 0.01 seconds and no longer than 0.05 microprocessor 97 is then able to control switching seconds after to. circuit 94 to produce an electrode configuration that Assume that water applied to cell 18 from source 12 will achieve the desired current level when sixty volt has a relatively low resistivity and that, for the elec operation is restored. To that end, once the appropriate trode area and separation described above, the resis electrode arrangement has been established, micro tance R of the water between the adjacent active elec processor 97 would then initiate the application of the trodes is on the order of 0.5 ohms. The current between higher potential to cell 18. the electrodes will then be on the order of 120 amperes. In addition to allowing a suitable configuration for This relatively high current level is depicted graphi 65 the electrodes 28 to be initially established in response cally in FIG. 7. to the particular water characteristics experienced, the At block 106, the microprocessor 97 in controller 96 control circuit 20 may, in some circumstances, also compares the total or pre-electrode current to some allow the electrodes to be reconfigured during opera

Page 18

tion of the system 10 in response to fluctuations in water 12, and 118 and different time limits to, t1, t2, and t3 can resistivity. In that regard, suppose that the microproces be employed as desired.

sor 97 determines that the threshold T is not exceeded at As noted previously, the spacing of the active elec any one of blocks 106, 112, or 118. The configuration of trodes is only one of the variables that influence the the electrodes is, in that situation, suitably matched to 5 interelectrode resistance and, hence, the current flow the water resistivity and a current of less than 30 an ing between the electrodes for a particular voltage ap peres is applied between the electrodes. The operation plied thereto. For example, the interelectrode resistance of the microprocessor 97 is then returned to the preced is also inversely proportional to electrode area. In that ing current monitor block 104, 110, or 116, as shown. regard, FIG. 9 illustrates an alternative construction of There, the current is monitored again and compared to 10 electrodes that can be reconfigured by a control circuit the threshold T to maintain the same electrode configu to allow the effective area, rather than their separation, ration as long as the threshold T is not exceeded. The of the electrodes to be altered as a function of water operation would then be restored to block 104 (as indi resistivity.

cated by the broken lines in FIG. 6) to allow a closer For simplicity, FIG. 9 illustrates only three electrode active electrode spacing to be established, if possible, 15 assemblies 124, 126, and 128. As will be described in without exceeding the acceptable current threshold greater detail below, additional electrode assemblies level T. (e.g., seventeen total) can be employed and alterna As will be appreciated, however, it may be undesir tively reconfigured as anodes and cathodes in the man able to perform this type of “running' adjustment under ner previously described in connection with FIGS. 2 some circumstances. For example, if a low “test' volt 20 through 8.

age is used during the electrode configuration process Each electrode assembly 124, 126, and 128 includes to avoid potentially damaging currents, the electrode four electrodes 130, 132, 134, and 136. These electrodes configuration can not be tested without interrupting the are made of an electrically conductive, fluid impervious higher voltage "electrolytic' operation of the cell. Al material, such as a ceramic, and have dimensions of ternatively, if the higher electrolytic voltage is used to 25 roughly 10 centimeters by 2.85 centimeters by 0.06' perform running tests of the electrode arrangement, the centimeters. The electrodes 130, 132, 134, and 136 are control circuit or cell may be damaged by the relatively supported in a common plane by a grid 138 formed of a high currents. dielectric material, which electrically and mechanically Recapping the foregoing discussion, substantially isolates adjacent electrodes, while allowing the faces of constant current operation of the cell 18 will be main 30 the electrodes to be exposed to the fluid. In the pre tained independent of one thousand fold changes in the ferred arrangement, the grid is molded around the elec water's resistivity, due, for example, to differences in trodes. Separate electrical connections 140 are then water supplies, variations in water composition, and provided to each of the electrodes by, for example, water temperature fluctuations. A chart comparing the soldering or fasteners.

various modes of operation described above as a func 35 The electrode assemblies 124, 126, and 128, as well as tion of water resistivity is provided in FIG. 8. As de any additional electrode assemblies employed, are re picted, the system could be constructed so that, in the ceived within the electrode retention grooves 50 and 68 event the water's resistivity is above 100 ohm-meter, the of a housing 26 of the type previously described. The system will operate in the first mode, in which the elec resultant electrolytic cell can then be operated by the trode spacing is smallest. In the event the resistivity is previously described control circuit 20 with several between 10 and 100 ohm-meter, the system would then modifications to the switching circuit 94 and the pro operate in the second mode, in which an intermediate gram instructions stored in ROM 99.

electrode separation is achieved. Further, in the event In that regard, the electrical connection of the vari the resistivity is between 1 and 100 ohm-meter, the ous electrode assemblies 124, 126, and 128 to the control system would operate in the third mode, in which the 45 circuit 20 is illustrated in FIG. 10. As shown, the active electrode separation is greatest. Finally, if the switching circuit 94 includes a relay 142 having eight resistivity is below 1 ohm-meter, the system will operate pairs of contacts A, B, C, D, E, F, G, and H. Contact in the shut-off mode in which current is no longer pro pairs A, B, C, and D are activated to control the elec vided to the electrolytic cell. The relationship between trode assemblies to be used as anodes and contact pairs the various resistivities and modes of operation given 50 E, F, G, and H are activated to control the electrode above will, of course, depend upon the construction and assemblies to be used as cathodes. operation of the system. More particularly, one side of each of the contact As will be appreciated, a variety of alternative con pairs A, B, C, and D is coupled to the positive output of figurations and operations of the electrolytic cell 18 and power supply 90. The other sides of contact pairs A, B, control circuit 20 can be employed. In that regard, 55 C, and D are connected to electrodes 136, 134, 132, and additional tests and connections of the seventeen elec 130, respectively, of electrode assemblies 124 and 128. trodes 28 could be employed. For example, the control Similarly, one side of each of the contact pairs E, F, G, circuit 20 could reconfigure the electrodes to operate and H is connected to the negative output of power electrodes 28a and 28g as anodes and electrode 28i as a supply 90, while the other sides of contact pairs E, F, G, cathode, to increase interelectrode resistance by eight 60 and H are connected to electrodes 134, 136, 132, and times its original value and decrease current by eight 130, respectively, of electrode assembly 126. The micro times its original value. A greater or lesser number of processor 97 controls the operation of the contact pairs electrodes than seventeen could alternatively be en in the following manner.

ployed. Seventeen electrodes are, however, currently Referring now to FIG. 11, the control circuit is ini preferred because they allow several different reconfig 65 tialized at block 144. Then, the microprocessor 97 acti urations of the electrodes to be achieved while always vates the power supply 90 at block 146 and sends an maintaining a charge on the outermost electrodes. Also, output to the relay 142 in switching circuit 94 to close different thresholds T can be employed at blocks 106, each of switches A, B, C, D, E, F, G, and H. As a result,

Page 19

all four electrodes of assemblies 124 and 128 are con additional electrode assemblies can be employed. Fur nected for use as an anode and all four electrodes of ther, more or less electrodes can be included in the assembly 126 are connected for use as a cathode. Thus, different assemblies. The arrangements depicted in the active area of electrode assemblies 124, 116, and 128 FIGS. 5 and 10 can also be combined to provide a sys is at a maximum, equal to roughly 115 square centime tem in which both the effective area and separation of ters. the electrodes can be altered by electrically reconfigur At block 148, the microprocessor 97 monitors the ing the electrodes to provide even greater control over current. If the resistivity of the water is low, the current current level and response to conductivity variations in may exceed the acceptable threshold T. The micro the water.

processor 97 makes this evaluation at time t1 and block O Those skilled in the art will recognize that the em 150 and, with the threshold T exceeded, reconfigures bodiments of the invention disclosed herein are exem the electrodes at block 152. Specifically, the micro plary in nature and that various changes can be made processor 97 provides outputs to relay 142 of switching therein without departing from the scope and the spirit circuit 94 to open contract pairs A and F. As a result, of the invention. In this regard, the invention can be electrodes 134, 130, and 132 of assemblies 124 and 128 15 employed in the treatment of fluids other than water will be connected for use as anodes and electrodes 134, used, for example, in lubrication, hydraulic, and pneu 132, and 130 of electrode assembly 126 will be con matic systems. Similarly, with appropriately selected nected for use as a cathode. Thus, the area of the elec sensors, the system can be made responsive to water trode assemblies is effectively reduced by one-fourth, characteristics other than resistivity increasing the interelectrode resistance and decreasing 20 Because of the above and numerous orother conductivity. variations the current.

and modifications that will occur to those skilled in the

At time t2, the microprocessor 97 again monitors the art, the following claims should not be limited to the output of current sensor 92 at block 154. A comparison embodiments illustrated and discussed herein. to threshold T is then performed at block 156 to deter mine whether the current has been decreased suffi 25 The embodiments of the invention in which an exclu ciently. In the event that it remains above the accept sive property or privilege is claimed are defined as able level, the microprocessor 97 again provides outputs follows:

to switching circuit 94 at block 158 to further open 1. Electrolytic fluid treatment apparatus for treating a switches B and E. As a result, electrodes 132 and 130 of fluid, said apparatus comprising several electrodes ex assemblies 124 and 128 are connected as a cathode and 30 posed to the fluid, support means for physically sup only electrode 130 of assembly 126 is connected as an porting said electrodes, electrical reconfiguration anode. At this point, the effective area of the electrode means for providing electrically reconfigurable inter assemblies is one-half its original value, further increas connections of a plurality of said electrodes with each ing the interelectrode resistance and decreasing the other, and sensing means for producing an output repre current. 35 sentative of a characteristic of the fluid, said electrical At time t3, the microprocessor 97 again monitors the reconfiguration means including means responsive to output of current sensor 92 at block 160. A comparison said output for automatically reconfiguring the inter to threshold T is then performed at block 162 to deter connection of the plurality of electrodes in response to mine whether the current has been decreased suffi said output during treating of the fluid. ciently. In the event that it remains above the accept 2. The apparatus defined in claim 1, in which the able level, the microprocessor 97 again provides outputs sensing means includes means for producing an output to switching circuit 94 at block 164 to further open representative of the resistivity of the fluid. switches C and G. As a result, only electrodes 130 of 3. The apparatus defined in claim 2, including energy assemblies 124 and 128 will be connected as cathodes source means for providing electrical current to the and only electrode 130 of assembly 126 will be con 45 electrodes, the electrical reconfiguration means includ nected as an anode. At this point, the effective area of ing means for controlling the flow of current between the electrode assemblies is one-fourth its original value, the electrodes actuated by the energy source means, the further increasing the interelectrode resistance and de sensing means including means for sensing the magni creasing the current. tude of current between the electrodes indicative of the Finally, the microprocessor 97 again monitors the SO resistivity of the fluid.

output of current sensor 92 at some time t, as indicated 4. The apparatus defined in claim 3, in which the at block 166. A test is performed at block 168 to deter support means supports the electrodes in a fixed physi mine whether the current has been reduced to an ac cal arrangement, the electrical reconfiguration means ceptable level. In the event that it has not, the micro including means for reconfiguring the interconnection processor 97 provides outputs to switching circuit 94 at 55 of the plurality of electrodes so as to adjust the effective block 170, opening all the contact pairs and preventing distance between electrodes powered by the energy further operation of the cell and damage to the system. SOCC leaS.

As with the previously described arrangement, in the 5. The apparatus defined in claim 4, in which the event that a particular electrical reconfiguration is de electrical reconfiguration means includes means for termined to be successful in achieving the desired cur reconfiguring the interconnection of the plurality of rent levels at blocks 150, 156, 162, or 168, the operation electrodes so as to change the effective area of the elec of the microprocessor 97 continues to loop through the trodes powered by the energy source means as a func test reconfigurations depicted in FIG. 6. As a result, the tion of the resistivity of the fluid. circuit can be used to adaptively respond to changes in 6. The apparatus defined in claim 3, in which the water resistivity with source, time and temperature. 65 electrical reconfiguration means includes means for As will be appreciated, the arrangement of FIGS. 9 electrically interconnecting a first set of the electrodes and 10 can also be altered as desired. In that regard, as as anodes and a second set of the electrodes as cathodes indicated previously and by the dotted lines in FIG. 10, when the output of the sensing means is representative

Page 20

of fluid resistivity above a predetermined threshold 16. The apparatus defined in claim 1, in which the level. support means encircles the electrodes and defines a 7. The apparatus defined in claim 3, in which the fluid path through the electrodes.

electrical reconfiguration means includes means for 17. The apparatus defined in claim 1, in which the electrically interconnecting a first set of the electrodes electrodes are plates having opposite edge portions, the for use as anodes and a second set of the electrodes for support means including a shell having a plurality of spaced grooves for receiving said edge portions of the use as cathodes when the output of the sensing means is plates.

representative of fluid resistivity below a predetermined threshold level. 18. Electrolytic fluid treatment apparatus for treating 8. The apparatus defined in claim 7, in which the 10 a fluid, said apparatus comprising an electrical power several electrodes include eight electrodes supported supply, several electrodes each for acting as different side-by-side, and in which the electrical reconfiguration types of electrodes including anodes, cathodes and neu means includes means for configuring the eight elec electrodestral electrodes depending on the connection of said with said power supply, means for intercon trodes, respectively, as anode, neutral, neutral, neutral, 15 necting selected cathode, neutral, neutral, neutral, when the output of said interconnecting ones of said electrodes with each other, the sensing means is representative of fluid resistivity tively reconfiguring the means including means for selec below a predetermined threshold. interconnections of said elec trodes with each other so that different sets of elec 9. The apparatus defined in claim 3, in which the electrical reconfiguration means includes means for 20 trodes are interconnectable to act as the same type of electrode, and sensing means for producing an output controlling the number of individual electrodes be representative of a characteristic of the fluid, said inter tween which current flows. connecting means being responsive to said output for 10. The apparatus defined in claim 1, in which the automatically reconfiguring the interconnections of said electrodes includes a multiplicity of electrode plates, electrodes in response to said output during treating of each of said plates having a connection edge and a con 25 the fluid.

nection tab projecting therefrom, each connection tab 19. A method of electrolytically filtering a fluid being roughly centered on its connection plate. which comprises passing the fluid between several elec 11. The apparatus defined in claim 10, in which the trodes, charging the electrodes to generate a current electrode plates are supported by the support means through the fluid between the electrodes, automatically with the connection edges substantially aligned in a 30 evaluating a variable characteristic of the fluid, and common plane. automatically changing the interconnection of the elec 12. The apparatus defined in claim 10, in which the trodes with each other based on the evaluation of the support means includes a shell having an internal cavity characteristic of the fluid.

and a pair of external channels, the connection tabs of 35 20. The method defined in claim 19, in which the the electrode plates projecting from said shell, and in characteristic of the fluid is resistivity. cluding several wires electrically connected to the con 21. The method defined in claim 20, in which the step nection tabs and positioned in said channels. of evaluating the resistivity of the fluid is performed by 13. The apparatus defined in claim 12, in which each monitoring the current applied between at least two of the electrodes.

of the external channels includes an electrode end, said 22. The method defined in claim 19, including arrang electrode ends of the channels being staggered relative ing the electrodes in spaced, side-by-side relationship, to the connection tabs of the connection tabs projecting and automatically changing the interconnection of the from the shell.

14. The apparatus defined in claim 1, in which the tanceelectrodes with each other to adjust the effective dis between charged electrodes as a function of the electrical reconfiguration means includes a switching 45 evaluated characteristic of the fluid. circuit for providing a plurality of switchable electrical 23. The method defined in claim. 19, in which several interconnections between the electrodes. of the electrodes include a plurality of individual ele 15. The apparatus defined in claim 14, in which the ments, and automatically changing the interconnection electrical reconfiguration means includes a micro of the electrode elements to adjust the effective charged processor for controlling the switching circuit to pro 50 area of at least one of the electrodes as a function of the vide the electrically reconfigurable interconnections evaluated variable characteristic of the fluid. between the electrodes. k k ce : k

Page 21

UNITED STATES PATENT ANDTRADEMARK OFFICE

CERTIFICATE OF CORRECTION

INVENTOR(S) : R. K. Erickson, et al.

It is certified that error appears in the above-indentified patent and that said Letters Patent is hereby Corrected as shown below:

Title page, item 56 - under Refs. Cited, insert --4,917,782 4/1990 Davies . . . . . . . . . . .204/152 and 5,062,940 li / 1991 Dacies. . . . . . . . 204/228 Title Page, item 57), Abstract, "source (12) should read --source (12)-- "cell(18) should read -cell (18)--.

"circuit (120)." should read -circuit (20)-

Signed and Sealed this

Ninth Day of May, 1995

BRUCELEBMAN

Attesting Officer Commissioner of Patents and Trademarks