CA1059291A - Water purification system - Google Patents

Abstract

ABSTRACT

A housing has an interior casing receiving a coolant. This casing is associated with a forced cooling system and has open ended tubular portions therethrough formed of electrically conducting metal. Glass ozone generating tubes are removably supported in the tubular portions by axial movement and are held in spaced ozone generating position by spacers on the tubes. The tubes have an electrically conducting silver coating on the interior surface and have an interior band engageable with the coating for admitting high voltage to the tube from a conductor leading into the tube.
A treatment tank associated with the ozone generating system has a recirculating conduit operably connected with the housing for the ozone generating tubes. An additional conduit extends from the treatment tank to a storage tank and a filter for filtering out coagulated material is provided in this conduit. The invention further includes a process for treating water to purify it for various purposes such as for removing impurities and removing metal ions in aqueous solution. The water is subjected to ozone to destroy virus and bacteria therein and to form coagulants from a combination of positive metal ions and negative ozone ions.
The water is also filtered to remove filterable material.

Description

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WATER PURIFICATION SYSTE~
This invention relates to a process and apparatus of treat-ing water.
It is often desirable to treat water to remove impurities such as for making distilled water. Ozone has heretofore been employed since it is well known that ozone destroys virus and bacteria. Ozone, however, has not met with wide usage since it is difficult to safely subject water thereto or to provide the necessary and practical detention time to destroy the virus and bacteria. It is also desirable at times to treat water for the purpose of removing metal precipitates from solution, for reasons hereinafter set forth, but in many cases the precipitates are too small to be picked up by filters which are economically feasible to use. Accordingly, it is a primary objective of the invention ~
to provide a process and apparatus of treating water having a broad !
range of usage so as to be useful for many purposes. -One example of use of the instant invention is in association ;
with making distilled water and another example is in association with electroplating processes wherein it is used to purify rinse solutions thereof. In both cases, it has been found that the de-sired purification can be obtained by treatment with ozone by the present process and apparatus. Also, in connection with electro-plating, rinse water therefrom after being treated with the present process and apparatus can be discharged into conventional water-ways or sewers. Such has not heretofore been possible under exist-ing regulations, since such rinse material if discharged in a waterway causes contamination and if discharged in a sewer destroys the necessary bacteria. It has not been possible heretofore to economically filter out the impurities in the rinse solution for re-using the solution because the impurities, which comprise left-over portions of metal in solution, are too small to be picked up by a common and inexpensive filter.

As a part of the invention, it has been found that to treat an electroplating rinse solution with ozone allows the rinse B

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~5{.~ 9~-~olution to be filtered sconom~cally, namely, by mean~ Or ~ ~and rllter of ~ to 7 micron ~ize, to remove impurltle~ which compri~e mostly metal ln olution. Without ~uch treatment the lmpLrltle3 cannot be removed ~rlthout complex filterlng apparatus5 reverse 5 riltering, or other ~eans llvhich are not economlcally feasible.
The rln~ ~ater rrom the electroplating process a~t~r being treated by the ln~tant inventlon can be used over and over. Th~
thoory Or operation i~ 8.9 follo~ra:
The dls~ l~ed or negative oxygen which e cists in ~ater make-P0 up has a negative pol~rity, attracting the po~ltlve lons o~ metalR, such aY copper $ons, into tha plating s41ution and locking them in suspen~ion where they stay until an electric potentlal i~ applied.
~uch potential and current drlves the mets.l ions out Or 9u9pen-sion ~d onto the work or ¢athode. The thickness Or the layer 15 depositêd i on the ~ork depends on the strength o~ the electric cur-rent and on the duration of the bath and the number of platlng applicatlorls.
As ~tated above, the electric potential separates the metal rroD. the solution. This formA positive ions or catlons and nega-~LO tive ions or anions, ~nd it is the3e ions that acoomplish the coat-lng. Aq an e$ample, in a soluble copper ~alt solutio~, a precipltate -characteristlc of a copper ~ulphate solution upen electrolys~ 9 i~l cu~ ~ so4 It is to be noted that the positive copper ions are eparated 25 and are rree in the solution, ~uch being hsld there andlocked in solution by negative o~cygen. Similarly, a solution of any other soluble sulphate or chlorlde will give the same reactlon, regard-less o~ the particular cation pre~ent ln the solution. Thus, it appear~ clear that the metal ions in electrop~at~ng solutions 30 are po3itive in nature. In a zi~nc solution, ~1~ another e~cample, metal passes into solution as po~it~ve ion~ upon electrolysis as represented by the equation ~tt +t Zn ~ 2~I ~ Zn ~ H2 1(~5~
The production o~ positiv~ metal ione appears t~ be accom-plished upon the metal salts being di~solved in acid or cyanlde in water ~n other metals al~o, ~uch a~ chromium, silver, nlckel, and the llke.
In connection with the above, lt is a known ~act that ozone or 03 i9 negative in it~ makeup. The ozone being negatlve ~111 thu~ comblne wlth the negative dlssolved oxygen to increa~e the magnetic rleld and attract the positlve metal ions ln the rinse water of an electroplating proces~ solutlon to ~orm the molecules, and as ~tated above it has been ~ound that the molecules ~ormed ln such combination nQmely, in a comblnatlon Or the metal lons and the negatlve ozone ions, are Or an enlarged coagulant slze ~uch that they can be riltered out. Without the ozone treatment, there 18 no ine~pens1~e or at lea3t economically reasible filter or proce~q 1~ that can pick up these impurities.
~8 ~tated, the ~lter used with the lnventlon ma~ 8i~ply comprise the usual sand ~ilters. A ~lter o~ ~ to 7 ml¢ron size ~ill e~fectively rilter out the molecules ln the used electrol~ti~
solutlon ~hlch has been treated wlth ozone.
As one example o~ the process, a bath Or 800 gallons rlnse 901ut~ on at room temperature ~as treated ~ith 20 grams o~ ozone by interjecting ozone treated air into the rinse ~ater. Such treatment was continuous ~nd the flltering li~ewise was contlnu-OU8 with a 5 micron ~ize ~ilter, it belng ~ound that the treat~ent according to the invention maintained the rinse solution in a con-dition such that it could be reused continuously. The riltered out molecules can be reclaimed for further use Or metal ex~sting therein.
The drawings hereof sho~ ~tructure by ~ean~ Or whlch the process is carried out.
Figure 1 i9 a diagrammatic ~ie~ Or electroplating apparatus ~n combination with the pre~ent l~vention~

Flgure 2 1~ an enlarged detall longitudinal sectional view Or mixing nozzle asse~bly for mixing ozone with the electroplatlng rinse ~olution;

~0~9'~91 Figure 3 i~ a diagramm~tlc view of a modified appa~tus included in the lnvention;
Figure 4 i~ an enlarged deta~l longitudinal sect~onal view Or another embodiment Or mi~ing nozzle;
Flgure 5 is an enlarged roreshortened longltudin~l sectional Vi8W Or an ozone generating unit incorporated in the invention;
F~guro 6 1~ an enlarged frsgmentary elevatlonal view o~ an ozone generating tube included in the ozone generating unit;
Figure 7 i8 an enlarged cross ~ectional view tak0n on the line 7-7 of Figure ~; and Figure 8 iB a cros~ sectional view taken on the line 8-8 of Figure 6~
With particular reference first to Figures 1 and 2 of the dra~ings, an electropl~ting process is shown wherein the numerals 10 designate rinse tanks which receive rinse solutlons rrom one or more plating tanks of convention~l con3truction, not shown, wherein upon supplying eleotric current to opposite terminal~J metal ln solution is deposited on the surface Or the articles. A~ter the articles ha~e been treated they are dipped in the rinse tank~ 10.
Accordlng to the present invention, a conduit 12 e~tends ~rom these tanks to a recel~ing tank 14. Leading fro~ thi~ latter t~nk i8 a conduit 16 di~charglng into aga~hering tan~ 18. Conduit 16 contains a pump 20 therein ~or pro~iding flow rrom tank 14 to tank 18.
One or more ozone gener~tors 22 haYe outlet communication with the conduit 16 by mesns o~ conduit~ 24 and tes connectlons 26.
Ozone is dra~n into the conduit 16 through nozzle members 28 dis-posed in the tee fittings 26 shown ih det~il in Figure 2. Each tee fitting 26 has screw threaded connect~on~ 30 between sections of :
the conduit 16, and the nozzle member 28 thereor has a scr~w thread-ed connection 32 ~ith a lateral 34 Or the tee. The nozzle member 28 has an outwardly opening ~ocket 36 for receiving the conduit 24 ~ and also has an elongated hollow shank portion 38 which upon thread-ed mounting Or the nozzle member in the later~l 34 profects ~nto the ~(~s~z9~
main pass&geway Or ths tee. The shank portlon 38 of the nozzle member i8 closed at lts inner end by a wall 40 and ha~ a plurality Or aperture~ 42 in its side walls.
Thorough mixing of th~ rinse ~olution with ozone take~ place in the area of shank portion 38 and al 90 in downstream portion~
Or the conduit 16. In fact, lt ha~ been found that a detention tlme i9 preferable, and for thi~ purpo~e the treated solution i8 passed through an elongated conduit, such as, for example, a con-duit up to 150 feet in length or even longer. Such elongatlon Or the condult provides an ~dequate detention tlme. It has been ~ound that a good detention time is about si~teen minutes. Also, it is preferred that the conduit 16 include 8 static mi~er ~ of well known constructlon therein to further effect erficlent ad-mixture o~ the ozone with the solution, Leading fro~ the gatherlng tank 18 18 a conduit 46 in which a pump 48 i9 lncorporated. Condu~t 46 lead~ to an assembly of fllter 50 connectHd in parullel and having an outlet conduit 52 leading b~c~ to the rinse tanX~ lO. Filters 50 are preferably of about 5 to 7 micron ~ ze to accomplish good filtering of the metal precipitate~.
In the operatlon of the present system, tha pumps 20 and 48 operate contlnually to circulste the rinse solution rrOm tanks lO
through tan~ 14, mixing nozzles 28, gathering tank 18, and filters 50. The ozone being mixed with the rinse solution combines with the positive lon~ to form a coagulant of a size which can be caught in filters 50~ In a preferred arrangement, the aperture~
42 are qulte small ln size and are great in number so that there i~ a good diffusion o~ the ozone ln the solution~
As an example of the proces~ wherein ln flltering a rinse ~olutlon of an electroplat~ng process which wa~ not treated w~th ozone through a fllter of about 5 to 7 micron slze, no appreciable amount of metal~ ln solution were picked up in the ~ilter. ~ow-ever, by treatlng approxlmately 1666 gallon~ of the rinse solution for ~our hours with 20 grams of ozone a spectographic analysis o~

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rnaterial backwa~hed from the fllter of about 5 to 7 micron ~lze was as follo~s:

Element Percent_of A~h mg/l ~n orlglnal sample (~ X 630) Iron 35 220 Zinc 20 130 Sillca 15 90 Aluminum 6 40 Phosphorus 3.5 22 Calcium 2.5 16 Chromlum 5 3o Nickel 2 12 Copper 1.5 9 1~ Magneslum 1.7 10 Cadmium 0.75 Potassium 0.7 4 ~`

Boron o.5 3 Tin 0.25 2 Lead o.o8 o.5 Vanadium 0.0~ 0.2 Titaniu~ 0.04 0.3 Barium 0.02 0.1 Zirconlum 0~02 0.1 Manganese 0.02 0.1 Molybdenum 0.01 0.05 Cobalt 0.01 0.05 Strontium 0.01 0.05 Silver 0.001 0.005 . .
~he le~t-hand column shows percent o~ ash and the right-hand column shows mg/l o~ metal coagulants that were caught in the ~ilter after ozone treatment, the total impurities caught thu~
; being a combination shown in the two columns.
Although the pX ~alues may vary somewhae in di~ferent rinse 3~ solutions of electroplating processes, the particular pH of such solutions does not materially enter into the e~foct of operation of the ozone on the solutionsO
By means o~ the above described apparatu~ ~or treating rins-ing solut~on~ for electroplating processesJ such solutlons can be 40 used over and over continuou~ly. Also, another advantage Or the present system is that the ozone ~ill o~idize the cyanide to cyanate and with continuou3 o~idation by ozone the c~anate will separate off as harmless gas.

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A~ stated hereinbe~ore, the pre~ent proce~ may al~o be used to treat sea water for the purpose of removing the po3itive sodium ion or salt therefrom. That i~, using the ~ame theory ex-plained above in connectlon with ths electrop~ ting, the treatment thereof ~ith ozone combines them with the negative lons to form molecules of a size which can be flltsred out economically. The trsatment of sea water ~ay be accomplished general~y by the appara-tu~ de~crlbed in connection with the electroplatin~ process.
Another embodiment Or the apparatus is shown in Figures 3-8.
This apparatus is not illustrated specifically in connection with an electroplating process but illustrates that the concept can have broader usage ~uch as for di~tilling water Hnd other purpoQes whlch may require purl~icatlon Or ~ater. The inlet 54 sho~n in thi~
embodiment may thu~ comprise an intake from any source of water to be treated ~uGh as tap water to be distilled, ~tagnant water to be treated, electroplat~ng solution to be treated, etc. A pump 56 1J disposed in the inl~t 54 and moves the water through ~ filter 58 communlcatlng by mean~ of a conduit 60 with a top portion of a treatment tank 62. An outlet conduit 64 extends from a bottom por-tion o~ treatment tank 62 to a bottom portion o~ a storage tank66. Movement of the ~ate~ from treatment tank 62 to the ~torage tank i8 aceomplished by a pump 68 in the conduit 64, and ~uch con-duit also has a filter 70 lncorporated therein tog~ther with con-trol ~alves 72 and 74 on opposite sldes of the ~`ilter and a check valve 76 on the upstream ~ide of the filter. Storage tank 66 has an outlet 78 ln ~hich is incorporated a pressure regulated valve 80 arranged to operate the pump 68 in a ~ell known manner ~hen" a aelected quantlty o~ ~ater i8 drawn off from the storage tank 66, thus maintainin8 the water in ths ctorage tan~ at a selected level.
It i~ deslred also that the treatment tank 62 be maintained at a selected level, and for this purpose a pressure opsrated sensor 82, or other suitable ssnsor, is in a circult 84 with a solenoid operated valve 86 controlling flow of water in the conduit 60. Upon emptying o~ tank 62 to a selected level ~lth relation to 1(~5~
the ~ensor 82, additlonal water ls pumped in through the inlet.
A tr~ or~r 8B may be employed ln the clrcuit 84 to proYid~ a low voltage ~y~tem for the sensor 82 in a well ~nown m~nner.
Treatment tank 62 has a vent 89 whlch prererably leads to an out~ide ~rea.
F~k~ing between the bottom of treatment tank 62 and the top thereor i~ a conduit 90 ha~ing a pump 92 therein. An ozone generator 92, to be descrlbed, has an outlet conduit g6 connected into conduit 90 by means o~ a tee connection 98, a check val~e 100 being di~posed in the conduit 96 to provide one way flow of ozone.
Tee connection 98, Figure 4, has a pair o~ nipple~ 102 and 104 threadedly connected to it and provlding threaded connection in the conduit 90. Nipple 102 has a venturi or throat 106 inter-mediate it~ snd~ as well as a flared i ~ t 108 at its inner end.
~ipplo 104 ha~ a nozzle 110 mounted on its inner end, and the tip end of this nozzls projects into the ~lared inlet end of the nipple 102. By the nozzle arrangement shown in Figure 4, pre~-sured ~low of fluid in the conduit 90 from the bottom of the tank to the top, namely, in the direction of arrows 112 in Figure 4, ozone i~ drawn in rrom the generator in the direction Or arrows 114 and intermi~ed with water being circulated through condult 90.
Thorough mixing of the ozone with the water and suitable intake is accompli~hed by the venturi action existing in the nipple 106.
Condult 90 has sultable pressure meter~ 116 therein together with one or more operating valves 118.
Tho ozone generator 94, Figures 5 and 7, comprises a tubular housing ha~ing a rear wall 120 and a removable front ~all 122.
Thi~ housing is substantially air tlght to confine generated ozons ln its clrcuit. A conduit 124 leads from the ~ront wall 120 to a 3 ~llter 126, Figure 3, o~ a suitable type ~hlch remo~e~ moisture from the outside alr that i~ to be drawn lnto the generator 94.
Such a filter may utilize for example silica ~el as the filtering medium. The u~e of ~uch a filter preYent~ the formation o~ nitric o~id~ within the generator.

1~59Z9l Formed integrally within the generator i~ an lnnar ¢asing 12~ forming a ~ater tight area through the medium o~ the tubular wall o~ the ca~ing 94 togethcr ~ith a rear wall 130 and a front wall 132. Inner cas~ng 128 comprises a cooling chamber ror gener-at~ng tubes to be described and i9 fllled with a cooling mediumsuch a3 water or other appropriate ~ummer-winter coolant. The coolant is circulated through a radlator 134, Figure 3, in a conduit 136 leading ~rom an upper forward portlon of the inner caslng 128 to a lower rearward portion of such caslng. A pump 138 is incorporated in the conduit 136 to provide clrculatlon, and an expanslon chamber 140 i9 provided at the upper connection ; of t~e conduit into the casln~ to prevent air lock. Conduit 136 has one or more suitable control valves 142 therein.
With partioular re~erence to Figures 5 and 7, inner casing 128 ha~ a plurality o~ longitudinally axtending tubular open-ended socket portion~ 1 ~ therein each receiving an ozone generating tube 146. Socket portions 144 are constructed Or an electrically eonducting material to form the condensing action with the tubes to form the ozone. Tubes 146 are constructed of glass and have outwardly pro~octing beads 148 on their exterior sur~ace which provide ~upport for the tubes in the ~ocket port~ons 1 ~ and provlde ~paclng of the outer surface of the tubes 146 with their 'r~spe,c~ive,, socket portions 1 ~ to proYide the neceYsary encirc-ling conden~ng space 150 around the tubes. Beads 148 are secured to the outer surface of the tubes and particularly are not formed by indentations from the glass, whereby the inner surface of the glass is unlnterrupted for proper condensing action.
With particular reference to Figures 5-8, tubes 146 comprise hermetically sealed tubular glass members having an input wire 150 pa~sing through the rront end of the tube in sealed relation~
Wlre~ 150 are connected to an insulator 152 mounted on the top wall of the generator housing and thèn~xtend to a source of high voltage. The hou~ing 94 ig grounded at 154, Figure 1. The input wlre 150 ror eaah tube supports a glass tube 156 and is connected ~US~

at its inner end to a ~pri~g band 158 ~hich ln e~panded ~or~ i8 arranged to clamp rlrmly hgainqt the inner surf~ce of the tube 146. The outer qurface of band 1~8 integrally support~ a eon-ductor material 160 such a~ copper gauze. Thi~ gauze i~ connected electrically to the wire 150. Such electrical connection ls accomplished by con~tructing the band 158 from an electrlcally conducting material, although if de~ired it i9 apparent that the uire end can lt~elf be ~ecured to the copper gauge band 1600 The inner surface of the tubes 146 has an el~ctrically con-ducting coating 162 such as silver, and thls coating extend~ allthe way around the inner periphery o~ the tube ~rom the rearward end of the latter to a point just forward of the copper band 160.
The numeral 164 designates the ~orward edgs of thls coating ~n Figure 6. Tubes 146 are filled ~ith nitrogen to prevent oxidiza-tion of fittings therein.
The tubes are in3erted i~ the open ended sockets 144 to thee~tent that the end edge 164 of the silver coating 162 i~ disposed ~n~ardly of the ~ront w~ll 132 of the housing. Upon the appllca-tion of a high voltage to the silver coating, the condenslng action ~hich exi~t~ between ~uch coating and the metal compartment 128 produoes ozone. The front ~all 132 i3 shown in phantom ln Figure 6 to sho~ the lnserted posltion of the tubes. Glass tube 156 has a length to e~tend rearwardly of the ~all 132 in the ln-serted positlon of the tube to pr~vent arcing between any e~po3ed posit~on of the ~ire 150 and the casing 128.
In the operation of the syste~ of Figures 3-8, raw water to be treated is admitted into the treatment tank 62 and is held at a level as dstermined by the sensor 82. With the pump 92 in oper-ation to continuously ¢irculate the ~ater from the bottom of treatment tan~ 62 arou~d to the top thereof, and ~ith the ozone generator 94 in operation, outside alr is dra~n ~n through ~llter 126 and ozone produ¢ed in the gener~tor 94 and then discharged through the mixing val~e 98. As 3tated hereinb0~0re, the pressure flo~ of the water through the nozzle 110 draws the ozone into the f~9~

mi~ing valve and produces thorough mixing thereor in the water.
Repeatad clrculation of the water through the treatment tank 62 and around the condult 90 providas for adequ~te treatment by ozon~ to destroy the ~irus and bacteria in the wQter and to rorm 5 the metal coagulants capable of being removed by the rilter 70.
Thi~ filter as well as lilter 58 m~y comprlse a ~and rllter ~uch a~ a 5-7 micron size ~and filter. The re~ultlng ~olution reaching the ~torage tank 66 thus comprlse~ water which can be commerclally used as distilled water or in other cases where it i9 desired to merely run o~f the water suoh a~ into a waterway or sewer system such as for the discharge of rinse water in an electroplating process, the ~ater meet~ the requirements of environmental regu-lations. The pressure regu~ tor 80 maintains the storage tank at a selected level by operatlon Or the p~u~p 6B a~ descr1bed herein-be~ore.
The clrculation of th~ water around through conduit 90 isat a selected rste of movement and the input from the ozone gener-ator 94 is sufricient to saturate the water with ozone. In an exemplary arrangement ~hereln the treatment tank comprised an 85 gallon tank and after initial treatment of the water circulatlng through conduik 90, 13 gallons could be drawn o~f every five minutes. Greater output could of course be obtained by enlarging the system.

Claims (6)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An ozone generating system comprising a housing having a closed interior with a removable end wall, a hollow casing in said housing including means to receive a coolant, the interior of said casing being isolated in sealed relation from the interior of said housing, a forced cooling system associated with said inner casing for circulating a coolant therethrough, at least one open-ended tubular portion extending through said inner casing, said tubular portion being formed of electrically con-ducting metal, at least one glass ozone generating tube having a diameter smaller than said tubular portion, an electrically con-ducting silver coating on the interior surface of said tube, a conductor leading into said tube for admitting high voltage into said tube, an electrically conducting band secured to said conductor and engageable with the coating around the interior of said tube, said ozone generating tube being removably supported in said tubular portion by axial movement thereof, spacer means holding said ozone generating tube centered in said tubular portion in circumferentially spaced relation thereto whereby said ozone generating tube upon a high voltage input being applied there-to operates with the metal in said tubular portion to provide ozone, the space between said ozone generating tube and said tubular portion communicating with the interior of said housing, and inlet and outlet means in said housing for receiving inlet-air and discharging generated ozone, respectively.

2. The ozone generating system of claim 1 wherein said spacer means comprises glass beads projecting from the outer surface of said tube.

3. The ozone generating system of claim 1 wherein said electrically conducting band comprises a spring band.

4. The ozone generating system of claim 1 comprising a treatment tank, means connecting said tank to a source of liquid to be treated with ozone, first conduit means located outside of said treatment tank extending from a bottom portion of said tank to a top portion thereof, pump means in said conduit for pressured pumping of water in said conduit, and second conduit means connecting the outlet means of said housing with said first conduit means whereby ozone from said hous-ing is drawn into said first conduit means and admixed with the liquid by the pressure flow of water past the point of entry of the ozone into said first conduit means.

5. The ozone generating system of claim 4 including a storage tank, third conduit means extending from said treat-ment tank to said storage tank, and filter means in said conduit between said treatment tank and said storage tank, said filter means comprising a 5 to 7 micron size filter.

6. The ozone generator of claim 1 comprising conduit means communicating angularly with said outlet means of said housing, a Venturi portion in said conduit means having a re-stricted throat with a cupped inlet, an intake nozzle projecting into said cupped inlet, and means arranged to move a solution to be treated with ozone under pressure through said conduit means, whereby pressured movement of the solution in said Venturi portion intermixes said ozone with said solu-tion.