SAWYER, Scott (6/10 Kortum Drive, Burleigh Heads QLD 4220, AU)
KNIPE, Mark (6/10 Kortum Drive, Burleigh Heads QLD 4220, AU)
SAWYER, Scott (6/10 Kortum Drive, Burleigh Heads QLD 4220, AU)
1. Apparatus for sanitizing a stream of water comprising a first electrolysis cell which produces ions with algaecidal and bactericidal properties and a second electrolysis cell which oxidizes water to produce hydrogen peroxide.
2. The apparatus of claim 1 in which the first cell has copper electrodes and the second cell has titanium electrodes with an electrocatalytic coating. 3. The apparatus of claim 1 in which air is introduced into the stream prior to entering the electrolysis ceils.
4. The apparatus of claim 3 in which the air is introduced by means of a venturi inlet.
5. The apparatus of claim 3 in which the air is introduced by a compressor.
6. The apparatus of claim 2 in which the polarity of the electrodes is periodically reversed at a frequency of from three to nine minutes.
7. The apparatus of claim 2 in which the second cell contains an ultrasonic pulse generator.
8. The apparatus of claim 1 which is controlled by a centra! programmable controller.
9. The apparatus of claim 1 in which the cells are generally cubic hollow bodies with opposing inlet and outlet pipes into which U shaped electrolysis plates are slotted through an opening transverse to the flow and made watertight by a screw top.
10. The apparatus of claim 9 in which one cell has an ultrasonic pulse generator built into its base.
11. The apparatus of claim 9 in which terminals carrying power to the electrolysis plates pass through the screw top and are sealed with grommrts.
FIELD OF THE INVENTION This invention relates to apparatus for keeping water clean and free of disease carrying organisms, especially for use in swimming pools.
BACKGROUND OF THE INVENTION Patent Application PCT/AU2004/103912 discloses apparatus comprising ionization means to produce ions having an algaecidal or bactericidal effect into the liquid, ultrasonic cleaning means to introduce sound waves into the liquid and electronic oxidation means to increase the oxidation reduction potential of the liquid, wherein the ionization means, the ultrasonic cleaning means and the electronic oxidation means are operated simultaneously for a period to clean and sanitise the liquid in the absence of added salt, chlorine or other chemicals.
The ionization means comprises electrodes of the alloy 85% copper, 10% zinc and 5% silver and is claimed to generate ions which have an algaecidal or bactericidal effect. In addition the copper and silver ions are claimed to maintain the conductivity of the water without the addition of chemicals, particularly chlorine, and without the operation of a salt water chiorinatton device.
However the inventors of the present invention have found that this prior art apparatus does require the addition of salt for effective operation. Further they have found that acid must be added to the water to lower pH which rises to unacceptable levels with the operation of the system. Accordingly a pool using this apparatus requires constant monitoring with the addition of chemicals to keep it free of living organisms and in pH balance. It has also been found that the configuration of the ionization cell following the electrolysis cell in the direction of flow as disclosed in PCT/AU2004/103912 is not optimum in relation to the sanitation process. OBJECT OF THE INVENTION
It is therefore an object of the present invention to provide water cleaning and sanitizing apparatus which does not require the addition of chemicals or at least reduces the use of chemicals in a swimming pool.
STATEMENT OF THE INVENTION
According to the present invention apparatus for sanitizing a water stream comprises a first electrolysis ceil which produces ions with algaecidal and bactericidal properties and a second electrolysis cell which oxidizes water to produce hydrogen peroxide.
Preferably the first cell has copper electrodes and the second cell has titanium electrodes coated with electrocatalytic metal oxides.
Preferably the polarity of the electrodes of both ceDs is periodically reversed at a frequency of from three to nine minutes. Preferably air is introduced into the water prior to entering the electrolysis cells.
Preferably the air is introduced by means of a venturi intake.
Alternatively compressed air may be injected by a compressor.
Preferably the second cell contains an ultrasonic pulse generator.
Preferably the operation of the electrolysis cells and the ultrasonic pulse generator are controlled by a central programmable controller.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention is now described by way of example only with reference to the accompanying drawings in which:
Fig 1 is schematic of a swimming pool cleaning and sanitizing apparatus and Fig 2 is an isometric view of an electrolysis cell of the apparatus.
DETAILED DESCRIPTION OF THE INVENTION
The schematic Fig 1 shows a pump 5 drawing water from a swimming pool (not shown) and pumping it through a sand filter 6. The latter filter 6 uses a glass filtration medium which removes dead algae, bacteria and dirt from the water which then passes through two electrolysis cells 2 and 3 connected in series and back to the pool. A venturi air intake is located in the flow at 17 prior to cell 2.
Cell 2 contains two pure copper electrodes the operating anode of which releases from .3 to .5 ppm of copper ions Cu++ into the water to control algae and bacteria. Cell 3 contains two pure titanium electrodes with electrocatalytic metal oxide coating which in operation generate hydrogen (H+), oxygen (0-) and hydroxy! (OH-) ions from water (H2O) molecules. Hydrogen peroxide (H 2 0 2 ), which is a powerful sanitizing agent, is formed from the reduction of dissolved oxygen in the water. Hydrogen Peroxide is specifically formed as a reduction product at the cathode of cell 3 by the electrocatalytic reduction of dissolved oxygen with water to form
Chlorine may also be formed in small amounts and this will occur especially when salt is added in increasing proportion. However cells 2 and 3 are
specifically configured to favor the generation of hydrogen peroxide which is also enhanced by the introduction of air into the flow at 17. The electrolysis process in cells 2 and 3 is controlled by controller 1 which draws power from a 240 volt mains supply 4 to provide direct current to cells 2 and 3 via cables 7 and 8. Circuit breaker 9 isolates controller 1 from supply 4 in the event of an electrical fault occurring. Controller 1 is programmed to reverse the polarity of both the copper and platinum electrodes in six minute cycles of operation. This cyclic reversal eliminates mineral build up on the electrode plates and increases their life.
An extension 10 at the base of cell 3 houses a generator (not shown) which pulses ultrasonic pressure waves through the water flowing in cell 3. Operation of the generator is controlled by controller 1 via cable 8 which can vary frequency and intensity of the ultrasonic waves to optimize destruction of parasites such as giardia and Cryptosporidium. Fig 2 shows the construction of cells 2 and 3 which have a generally cubic hollow body 11 with entry pipe 12 and exit pipe 13. The top of cells 2 and 3 is formed as a threaded necked opening and mating collar 14 screws onto it thereby retaining transparent cover 15. U shaped electrolysis plates (not visible) slot into body 11 and electrical terminals (not shown) extend from the plates through holes 16 in cover 15. Collar 14 forms a water tight seal with body 11 and holes 16 are sealed with rubber grommits around the terminals. Accordingly cells 2 and 3 are water tight and pool water does not leak from them.
Although the system operates effectively without the addition of chemicals, it is advantageous to add small amounts of magnesium and potassium salts. The latter have a "softening" effect on the water and magnesium and potassium chloride produce residual chlorine by ionization in the electrolysis cells for countries where a minimum chlorine content is required in pool water.
Test 1. One thousand litres of municipal supply water with a chloride
concentration of <10 ppm was recycled using a typical swimming pool pump through the subject apparatus comprising catalytic coated titanium electrodes and ultrasonic cell in series. After 2 hours a residual of 1 ppm H 2 0 2 was achieved.
Test 2. One thousand litres of municipal supply water with a chloride
concentration of <10 ppm was recycled using a typical swimming pool pump through ttie subject apparatus comprising catalytic coated titanium electrodes and ultrasonic cell in series. Air was introduced at low flow (~ 20 l/minute) through an inlet prior to passage of the water through the electrolysis and ultrasonic cells. After 3 hours a residual of 2 ppm H 2 0 2 was achieved.
Test 3. One thousand litres of municipal supply water with a chloride
concentration of <10 ppm was recycled using a typical swimming pool pump through the subject apparatus comprising catalytic coated titanium electrodes and ultrasonic cell in series. 167 ppm of Sodium Bicarbonate, and 500 ppm of Magnesium Chloride were added to the solution. Air was introduced at low flow (~ 20 l/minute) through an inlet prior to passage of the solution through the electrolysis and ultrasonic cells. After 40 minutes a residual of 1 ppm H 2 0 2 , and 0.6 ppm Chlorine was achieved. It will be obvious that the apparatus of the present invention requires minimal addition of chemicals to pool water which results in lower maintenance costs than prior art systems. Further since hydrogen peroxide is a highly effective and odorless oxidising agent, water treated by the system will be freer of contaminating organisms than those systems which rely on residual chlorine which has an unpleasant odor. VARIATIONS tt will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth. Throughout the description and claims of this specification the words "comprise" and variations of that word such as
"comprises" and "comprising" are not intended to exclude other additives components integers or steps.