Abstract:
The invention provides a liquid purification apparatus ( 10 ) adapted to employ the combination of the purifying effects of the heavy metals copper and silver in conjunction with hydrogen peroxide and the catalytic reaction thereof. A body means ( 11, 12 ) defines a flow passage ( 13 ) having a liquid inlet ( 14 ) at one end and a liquid outer ( 16 ) at the other end. Flow passage ( 13 ) has a first electrolytic unit ( 60 ) containing at least one copper based anode ( 22 ) and a second electrolytic unit ( 62 ) containing at least one silver based anode ( 25 ) spaced downstream of first electrolytic unit ( 60 ). An electrical circuit means ( 32 ) supplies operating current thereto and flow passage ( 13 ) includes an inlet ( 34 ) for the controlled introduction of H 2 O 2  from reservoir means ( 51 ) into flow passage ( 13 ) between first ( 60 ) and second ( 62 ) electrolytic units.

Description:
TECHNICAL FIELD OF THE INVENTION 
     This invention relates to liquid purification apparatus and methods of using same. The invention is directed to apparatus for purifying water by the well-known process of heavy metal purification using the bacteriostatic effects of silver, as well as the algaecidal effect of copper, whilst hydrogen peroxide is introduced because of its catalysed decomposition by either one or both of these metals to produce oxygen. The invention will be described in the preferred embodiments in its particular application in destroying disease-carrying bacteria in drinking water, but it will become apparent that the invention is not limited to this particular field of use, with wider and different applications being possible. 
     BACKGROUND OF THE INVENTION 
     As is well known and made the subject of the prior art, the high affinity that Ag+ ions have to —SH and other groups makes it an efficient biocide. If hydrogen peroxide (H 2 O 2 ) is simultaneously added the former causes a catalytic reaction with the H 2 O 2  to increase the efficiency quite considerably as H 2 O 2  is also a biocide. As a result, this process can be used to sterilise drinking water, or water that may be in contact with humans, such as water in pools, spas and the like. 
     Various attempts have been made in the past to devise apparatus and methods for the effective use of metal ions of silver and copper with H 2 O 2 , but for a number of reasons success has not been attained. In consequence, no marketable technology is currently available, due mainly to difficulties in handling the H 2 O 2  , and controlling the dosages required. Many prior proposals have involved usage systems requiring labour intensive packaging in an endeavour to achieve accurate levels of all three additives, namely Ag+, copper and H 2 O 2 . For example, U.S. Pat. No. 2,105,835 of Krause prescribed individual packaging, using tablet form, enclosed in soluble wrappings which gradually dissolve, encased in soluble crystals, powder mixes, adding to ice, and so forth. Likewise, United Kingdom specification No. 432101 of Katadyn A, G, discloses the use of packets, tablets, pills, capsules or ampoules, soluble coating of crystals or gelatine. Thus in the prior art the dosing of metals and H 2 O 2  involved cumbersome procedures and apparatus, with the apparatus also being expensive to manufacture, and in the main only specific predetermined bodies of water could be treated. 
     A major problem with the prior art arose from the fact that the handling of H 2 O 2  to perform the aforementioned functions had been found dangerous and likely to prove harmful to users. The strength of H 2 O 2  required was between 30 to 50% strength, and this made it dangerous bearing in mind that H 2 O 2  at even 8% strength is an irritant to the skin and is corrosive at 20%. To dose any large amount of water, such as 50,000 liters, using 15% strength H 2 O 2  would require a massive volume of hydrogen peroxide, and obviously dosing with H 2 O 2  at 50% strength would pose a serious health threat to the user. 
     OBJECTS OF THE INVENTION 
     The present invention has as its principal object to provide apparatus which will ameliorate at least some of the problems associated with the prior proposals by effectively controlling the dosages of silver ion release and copper ion release, as well as the supply of H 2 O 2  relative to a predetermined and controlled flow of water which is subjected to said dosage, in a manner achieving both safety and increased efficiency of operation. 
     A further object of the invention is to provide apparatus of the type just described which will allow effective control of the dosing of the H 2 O 2  and the metals within an in-line flow passage for the water, regardless of the volume being passed, or the actual flow rate, and regardless of contamination present. 
     Yet another object of the invention is to provide such apparatus and usage methods which will ensure that the opportunity of the H 2 O 2  to come into contact with the user will be eliminated, while at the same time the dosing system will allow the introduction of all and any of the aforesaid elements, while avoiding wastage of any products involved and eliminating the production of chemical by-products eg hydroxides. 
     Other objects and advantages will be hereinafter apparent, such as providing advantages over the prior art in that the apparatus will not be subject to operational difficulties in areas where temperature variations may be extreme. 
     SUMMARY OF THE INVENTION 
     With the foregoing and other objects in view, the invention provides a liquid purification apparatus adapted to employ the combination of the purifying affects of the heavy metals copper and silver in conjunction with hydrogen peroxide and the catalytic reaction thereof, said apparatus including body means defining a flow passage having a liquid inlet at one end and a liquid outlet at the other end, said flow passage containing a first electrolytic unit containing at least one copper based anode, a second electrolytic unit containing at least one silver based anode spaced downstream of said first electrolytic unit, electrical circuit means being provided in association with the electrolytic units for supplying operating current thereto, and said flow passage including an inlet for the controlled introduction of H 2 O 2  from reservoir means into said flow passage between said first and second electrolytic units. 
     The invention has a number of other broad aspects which will be apparent from the later described and illustrated embodiments which serve to show the many variations which may be selected. In a simple form, two identical inverted T-shaped housings may be connected in line so that they have a single inlet at one end and a single outlet at the other for connection to respective supply and delivery lines, with a single flow line therebetween into which the copper and silver electrolytic units extend radially from the upper body parts, both units being fitted in such manner that they may be easily removed when desired. 
     Typically, the silver electrolytic unit will comprise a single anode of silver having a pair of stainless steel cathodes at equal distances on opposite sides, all three suitably being in a radial plane extending longitudinally of the flow line. Similarly the copper electrolytic unit has a single copper anode and two stainless steel cathodes arranged in the same way and the same relative dispositions as just described for the silver unit, all cathodes and anodes being coplanar and having their free ends projecting into the chamber defining the flow line, while the opposite or fixing ends of the cathodes and anodes are connected to each other in each respective unit. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings, wherein: 
     FIG. 1 shows schematically in elevational view the overall general arrangement of a first embodiment of a water purification apparatus according to the invention; 
     FIG. 2 shows in greater detail and in cross-sectional side elevation the two interconnected bodies or housings shown at the bottom of FIG. 1; 
     FIG. 3 shows in greater detail the electrical circuit means for the silver anode and copper anode units; 
     FIG. 4 shows the steel connecting tube for the H 2 O 2  reservoir; 
     FIG. 5 shows an enlarged view of the cutting tip of the steel connecting tube shown in FIG. 4; 
     FIG. 6 is a cross sectional side elevation of two interconnected bodies or housings, similar to that shown in FIG. 2, but showing an alternative arrangement employing three similar electrodes; 
     FIG. 7 is the power supply and wiring circuit diagram for the alternative arrangement shown in FIG. 6; 
     FIG. 8 is a schematic drawing showing the anode distribution and wearing mode provided by the alternative arrangement shown in FIG. 6, when the central electrode is acting as an anode; and 
     FIG. 9 is a similar view to that of FIG. 8 with the central electrode acting as an cathode. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The apparatus shown in the drawings includes a treatment housing  10  having two interconnected bodies  11  and  12  defining a horizontal flow chamber or flow line  13  between an inlet end  14  connected to a supply pipe  15  and an outlet end  16  connected to a delivery pipe  17 . Each body  11  and  12  has a top branch part  18  or  19  fitted with threadedly removable upper assemblies  20  and  21 . The bodies  11 , 12  are preferably made of P.V.C. or other suitable material and have aligned or coaxial cylindrical chambers for the inlet end  14  and outlet end  16 . The top branch parts  18  or  19  are perpendicular to flow line  13  and are fitted with electrodes and electrical connectors. In normal usage disposition of the apparatus, the aligned housings or bodies  11  and  12  have their axes contiguous and horizontal, but the upper parts could also operate if they extended down vertically or at any other convenient angle. 
     The assemblies  20 ,  21  contain electrolytic cells  60 , 62 . It will be seen from FIG. 2 that there are six electrodes comprising a copper anode  22  in association with two stainless steel cathodes  23  and  24  to form cell  60 , and a silver anode  25  in association with two stainless steel cathodes  26  and  27  to form cell  62 , all being spacedly mounted as illustrated for the flow of water therepast. FIG. 2 shows the removable features of the upper parts which support the electrodes so that their fixing ends are interconnected and have respective circuit means  28  and  29  through plug-in means  30  and  31  (see FIG. 2) for connection in circuit to the control box  32 . The control box  32  may receive electrical power from the same source that activates an electrical pump used to pump the water to the supply line or pipe  15 . In turn, current is caused to flow between the electrodes, and at the same time a pump  33  will be actuated to draw H 2 O 2  from a reservoir  51  to an entry port assembly  34  in housing  10 . Entry port assembly  34  may be threadably engaged with flow line  13  so that its inner end is a delivery nozzle within flow line  13  whilst its outer end receives a supply tube, preferably nylon, coupled to pump  33 . Pump  33  is of the peristaltic type but any suitable pump may be substituted. Pump  33  ensures that H 2 O 2  is forced non-returnably into the pressurised water flow line  13 . The operating pressure of pump  33  may be manually adjustable by means of control means  39  in FIG.  1 . Pump  33  may, if required, be replaced by a gravity feed device or solenoid operated valve arrangement. 
     FIGS. 4 and 5 show a self-opening tube  35 , preferably formed from stainless steel. having a lower cutting end  36  with cutting edges  37 . Cutting edges  37  provide a self-drilling or tapping feature which allows tube  35  to be inserted into a sealed container  51  of H 2 O 2 . The cutting end  36  of stainless steel tube  35  is so shaped and designed as to allow full flow and at the same time be capable of performing a self-centring drilling action when turned like an auger. After the drilling has been completed tube  35  may be inserted to the full depth of container  51 . Accordingly, an operator will not be exposed to H 2 O 2  and no skin irritation can occur. Cutting edges  37  will also not impede flow of H 2 O 2  into the tube  35 . Near the H 2 O 2  container  51 , the upper eternally-exposed part of the inserted stainless steel tube  35  has a T-section arm fitted with a needle valve  38  for manual control. From this branch, other liquids that may be required from time to time may also be introduced into the water, such as hydrochloric acid or sodium hydroxide to obtain a pH balance, or to introduce corrosion inhibitors such as polyphosphates. 
     FIG. 1 also shows two current meters  40  and  41  for the copper and silver units, respectively, with manual knobs  42  and  43  for adjustably varying the rheostats  44  and  45  shown in the circuit diagram of FIG.  3 . Numeral  46  indicates the power supply in, and the numerals  47  and  48  indicate the power supply out in respect of the two heavy metal units. The gauges or meters  40  and  41  are also shown in FIG. 3, each having resistor means indicated at  49  and  50 . 
     The manner of operation will now be described. On start up, water flows in through supply pipe  15  and enters treatment housing  10 . Pump  33  will draw H 2 O 2  from container  51  and dispense the H 2 O 2  through entry port assembly  34  into flow line  13 . Electrolytic cells  60 , 62  will be activated to release copper and silver ions respectively into flow line  13 . By placing the copper electrode  22  upstream of silver electrode  25  a synergistic reaction occurs with respect to the copper and silver ions released into the water and the H 2 O 2 . Total catalysation of HO 2  will occur resulting in hyper-oxygenation of the water. This contrasts with the prior art where hydroxyl production can occur. The introduction of the H 2 O 2  after release of the copper ions and prior to the release of the silver ions provides this unexpected optimum hyper-oxygenation. By having silver electrode  25  downstream of copper electrode  22  the tendency of silver ions to silver plate the copper electrode is also substantially reduced and copper ion release is not hindered. This results in more effective use of the silver and a reduction in downtime for cleaning electrodes. The upper assemblies  20 , 21  are readily removed when desired, as will be the need in applications where copper, in particular, may become an electrolysis corrosion problem eg cooling towers. 
     In trialing and field testing the apparatus as aforedescribed, it has become apparent that the commercial viability of the technology therein could be enhanced by improvements relative to service aspects thereof. In this regard two main aspects of servicing have become apparent being regularly occurring problems involving additional manpower and time namely (1) cleaning of the anode and (2) replacing used anodes. 
     Naturally it is not possible to ameliorate the need to replace anodes as they are consumable items, and thus attention was directed to the development of a system which will eliminate the aspect of cleaning the anodes and in consequence extend the service life whereby anodes are replaced less frequently. 
     As FIG. 6 is very similar to FIG. 2 the same reference numerals will be used to show integers identical to those in FIG  2 . As shown in FIG. 6 stainless steel cathodes  23 , 24  of the earlier embodiment have been removed and replaced by copper electrodes  64 , 66 . Electrodes  64 , 66  are of the same size and composition as centre copper anode  22 . Similarly, stainless steel electrodes  26 , 27  are replaced by silver electrodes  68 , 70 . Reference should be made to FIG. 7 which shows the power supply and wiring circuit diagram to supply up to a 6v DC adjustable reversing current to the electrodes  22 , 64 , 66 , 25 , 68 , 70 . An alternating current  72  is supplied through switch  74  and its voltage can be controlled by variable impedance  76 . A transformer  78  reduces the alternating voltage to allow rectification to direct current by bridge rectifier  80 . The direct current is connected to the contacts of a relay  82 . A timer  84  controls relay  82  by switching the sets of contacts between the two illustrated positions. An ammeter  86  may be provided to give a visual indication of the current being drawn. 
     In the position shown in FIG. 7 positive terminal  88  will be connected to the anodes  22 , 25  whilst negative terminal  90  will be connected to the cathodes  64 , 66 , 68 , 70 . As can be seen when timer  84  times out the relay contacts will be shifted causing terminals  88 , 90  to be reversed with terminal  88  becoming negative whilst terminal  90  will become positive. The reversing of the polarity is timed so as to create an even wearing and cleaning of all electrodes. Accordingly, central electrodes  22 , 25  will be anodes with the pairs of outer electrodes  64 , 66 ; 68 , 70  being the cathodes, and when the current is reversed the centre electrodes  22 , 25  will be the cathodes and the outer electrodes  64 , 66 ; 68 , 70  will be the anodes. This will allow cleaning of the anodes which attract different contaminants when acting as anodes. Copper and silver ions can be thus produced continuously in a cleaning mode. In practice, by setting timer  84  to activate the centre electrodes  22 , 25  as anodes for, say, 15 minutes and then reversing the polarity for, say, 30 minutes the outer two electrodes  64 , 66 ; 68 , 70  are activated as anodes, an optimum condition is met. This switching can repeated in a continuous manner. Such a procedure will increase the life of the electrodes by up to three times 
     FIGS. 8 and 9 show how the even wearing of all electrodes will take place. In FIG. 8 central electrodes  22 , 25  are acting as anodes and will release metal ions from two opposing surfaces  92 , 94  at the one time as shown by the arrows. However, once the current is reversed and the outer electrodes  64 , 66 ; 68 , 70  act as anodes (FIG.  9 ), metal ions will be released from only one side  96 , 98  of each electrode  64 , 66 ; 68 , 70 , thus requiring twice as much time to reduce the size of the outer electrodes to the same size as the middle electrodes  22 , 25 , and to produce the same amount of metal ions per minute as when the centre electrodes  22 , 25  acted as anodes. It will be apparent that at no time during the operation of the system will the release of metal ions be restricted. 
     It has been previously mentioned that the invention provides improvements in liquid purification apparatus, and it will be understood that there are many applications for purified water apart from drinking purposes. Not only is purified water desirable in pools and similar bodies of water, but is can be important for water used in hosing down carcasses and food containers for example. Also with increased demand for usage of sewage water for golf courses and golf greens, the invention is capable of disinfecting sewage water which is thereafter sprayed or otherwise applied to the golf greens or fairways, these being examples which further show the wide application of the invention. 
     The invention will be understood to embrace many further modifications as will be readily apparent to persons skilled in the art and which will be deemed to reside within the broad scope and ambit of the invention, there having been set forth herein only the broad nature of the invention and certain specific embodiments by way of example.