AU2006101074A4 - Chilled Water Apparatus - Google Patents

Description

INO

O FIELD OF THE INVENTION O The present invention relates to a chilled water dispensing apparatus. In some embodiments, the present invention more particularly relates to a chilled water dispensing Sapparatus for dispensing filtered water or pre-treated bottled water.

BACKGROUND TO THE INVENTION Municipal water supplies are designed to provide safe, potable water to domestic and industrial users. Typical municipal water supply treatments include filtration Sthough sand filters to remove bulk particles, flocculation to remove colloidal particles and chlorination to kill bacteria in the water. The treated water leaving the municipal water supply treatment plants then passes through a water distribution pipeline network for distribution to end users.

The water supply pipeline network of municipal water supplies almost invariable provides a source of potential contamination of the treated water. In particular, it has been found that the inner surfaces of the pipeline supply network become coated in a biofilm that contains slime, algae and microbial growth. Such bio-films have the potential to cause contamination of the water flowing through the pipeline network.

The chlorine compounds used in municipal water supply treatments kill bacteria present in the water at the point of injection of the chlorine compounds at the water treatment plant. The chlorine compounds also persist in the water and continue to kill bacteria in the water as the water flows through the pipeline supply network to the end users. In this fashion, potable water having essentially no bacterial contamination can be supplied to the end users of the water.

Unfortunately, it is impossible to guarantee the correct functioning of the water treatment plants at all times. Incorrect functioning of the water treatment plants can have serious consequences. For example, the water may be inadequately disinfected leading to microbial growth in the water, such as cryptosporidium and giardia. Both organisms have the potential to cause serious illness. For example, a cryptosporidium outbreak in the city of Milwaukee, Wisconsin in 1993 caused the deaths of more than 100 people, with 400,000 (in a city having a population of approximately 1.3 million) becoming ill. Cryptosporidium and giardia scares have also occurred in Sydney, Australia.

-2- An increasing number of people are also concerned about continually ingesting treated water that contains one or more chlorine compounds. Such chlorine containing compounds arise from injection of the disinfecting chemicals into municipal water supplies.

OThe increasing concerns over the safety of municipal water supplies has led to a significant increase in the use of water dispensers that dispense treated water. Such water dispensers can dispense chilled water, hot water, or both. Such dispensers usually fall into two 0 categories: 0 a) dispensers that dispense bottled water, which bottled water has been taken from a natural spring source or which has been pretreated prior to bottling to remove N 10 microorganisms and chemicals; or b) dispensers that include water treatment systems that remove microorganisms and chemicals.

Bottled water that is supplied to the dispensers described in above is typically prepared by processing the water in a manufacturing facility to remove microorganisms and water treatment chemicals. Such processing will typically include a combination of filtration, micro-filtration, ultra-filtration, absorption through activated carbon beds or carbon blocks, UV radiation, reverse osmosis and the like. The treated water is then placed into sterilised bottles and the bottles are sealed with appropriate closures. The bottles are then typically transported at ambient temperature to another site where the bottle is stored (usually at ambient temperature) before being inserted into a refrigerated water dispensing unit.

Once inserted into the water dispensing unit, the water contained into the bottle passes into the dispensing unit where it is stored at temperatures of typically between 2 0 C and 6 0 C and for what can be a period of time ranging from one hour to many weeks, or even months.

During the manufacturing process of a bottle of water as described above, random sampling and chemical and bacteriological testing may occur to ensure that both the manufacturing process itself and the product produced by the manufacturing process meet all mandatory health standards. Despite this, studies have shown that microbial contamination of bottle water can occur. In particular, the containers and closures used for water bottling are a potential source for bacteriological contamination, especially for multi-service bottles to be fitted into a water dispensing unit. Further, once the bottled water has been delivered to an end user, there is no further quality control procedure required of, or applied by, the manufacturer.

O A further problem arises in that the storage reservoirs or tanks in the water dispensing units themselves can sustain bio-films. Such bio-films comprise a layer of microorganisms d contained in a matrix (usually a slime layer). The bio-films form on surfaces in contact with water or other liquids. Incorporation of pathogens in bio-films can protect the pathogens from C 5 concentrations of biocides that would otherwise kill or inhibit these organisms if they were freely suspended in water.

Other water dispensing units, such as those described in above, include water treatment systems. These water dispensing units are typically connected to the municipal ID water supply. Pressurised water from the municipal water supply passes though the water treatment system to remove the water treatment chemicals and microorganisms. A typical water treatment system used in such water dispensing units may include a filter bank connected in series and comprising a sediment filter, a pre-carbon filter, an ultra-filtration filter, a postcarbon filter and a pi-water filter (which is water-energising and mineral element filter). The treated water emanating from the water treatment system is then passed to storage reservoirs.

The storage reservoirs may include a chilled water reservoir and a hot water reservoir.

Appropriate taps are used to control the flow of water from the reservoirs. The units may be provided with appropriate control systems to ensure that the water reservoirs are maintained at an appropriate water level.

The water dispensing units may also or alternatively include reverse osmosis treatment systems.

In alternative water dispensing units, rather than being connected to the municipal water supply, the water dispensing units may include a dehumidifier that acts to condense water from the atmosphere, with the condensed water being collected, subject to appropriate treatment and sent to water reservoirs such as chilled water reservoirs and hot water reservoirs. These devices may include similar water treatment systems as described above, optionally with the addition of a UV treatment chamber in which the water is irradiated with ultraviolet light in order to kill any microorganisms in the collected water.

It has been assumed that the water that is sent to the reservoirs of water dispensing units as described above is essentially free from contaminant microorganisms and chemicals. Therefore, it is also been assumed that the water reservoirs are also free from contaminant microorganisms and water treatment chemicals. Studies conducted by the present inventor have shown that hot water reservoirs in water dispensing units, particularly those hot Swater reservoirs that are operated at a temperature of >90'C, do remain essentially free from Smicrobial contamination.

SIt is also been thought that the lower temperatures of the water in the chilled Swater reservoirs (which typically operate at between 2 0 C and 7 0 C) would minimise or suppress the growth of microorganisms. However, studies conducted by the present inventor have found that this is not, in fact, the case and that significant microbial contamination can be detected in chilled water reservoirs of water dispensing units. Further studies conducted by the inventor discovered that bacteria could grow in a bio-film formed on the inside surfaces of the ID chilled water reservoir, with the bio-film and bacterial growth occurring even at the low temperatures maintained in the chilled water reservoir.

To rid a chilled water reservoir of a water dispensing unit of bacteria present in the reservoir would normally require complete disassembly of all internal plumbing, water or fluid recirculation paths, and components, followed by a strong disinfection treatment of the water dispensing unit systems using chlorine based disinfectants or other approved biocides.

As there is no provision for a secondary or residual disinfection treatment in any water dispensing unit currently manufactured, the problem of bacterial contamination is likely to reoccur quickly after such a decontamination process has taken place. Further, because the main goal of using a water dispensing unit is to provide consumers with the purest and safest dispensed water, the use of chemical disinfection treatments normally associated with water treatment is undesirable. This is particularly save for refrigerated liquids stored in the chilled water reservoir. These liquids have already undergone extremely rigorous filtration and other treatments specifically targeted at removal of all biological matter and chemicals known to be harmful to human health (such as organochlorines, pesticides, heavy metals etc). It is anomalous to contemplate introducing chemical disinfection compounds into the chilled liquids after they have been processed to such a high standard.

BRIEF DESCRIPTION OF THE INVENTION In a first aspect, the present invention provides a water dispensing apparatus including a chilled water dispenser, the apparatus comprising a chilled water reservoir, a water outlet in fluid communication with the chilled water reservoir for dispensing water therefrom, flow control means for controlling the flow of water through the water outlet, an ozone generator for treating air passed to the ozone generator to partially convert oxygen in the air to ozone to form a mixture of air and ozone, and injection means for injecting the mixture of air Cand ozone into the chilled water reservoir.

The chilled water reservoir may receive water from a pre-treated supply of Swater. For example, the chilled water reservoir may receive pre-treated water from a bottle of water. In this case, the bottled water is suitably pre-treated at a bottled water manufacturing Splant and the bottles of water delivered to the site of the water dispensing apparatus.

Alternatively, the apparatus may further include water treatment means for treating water, said water treatment means being located upstream of the chilled water reservoir Osuch that water flows through the water treatment means prior to flowing into the chilled water N 10 reservoirs.

The water treatment means may include one or more of a sediment filtration unit, a pre-carbon filtration unit, an ultra-filtration unit, a post-carbon filtration unit, a pi-water filter, a reverse osmosis apparatus, an ultraviolet light flow chamber, or indeed any other water treatment system known to the person skilled in the art. Suitably, the water treatment means removes chemicals from the water (including organic chemicals and chlorine-containing chemicals). The water treatment means also suitably removes or kill microorganisms present in the water. The water treatment means may also remove heavy metals and other dissolved components from the water.

The water treatment means may be supplied with water from a municipal water supply. Alternatively, the water treatment means may receive water from a condenser that condenses water from the atmosphere. It will also be appreciated that the water treatment means may receive water from a bore, a well, a dam, a stream or river, or indeed any other source of water.

The ozone generator used in the water dispensing apparatus of the present invention partially converts oxygen in the air to ozone to form a mixture of air and ozone.

Preferably, the ozone generator includes a corona discharge. In this embodiment, the water dispensing unit suitably further includes an air supply means for supplying air to the ozone generator. The air supplied to the ozone generator is exposed to a corona discharge which causes some of the oxygen in the air to be converted into ozone. A mixed stream containing air having a quantity of ozone therein is removed from the ozone generator.

0 In some embodiments of the present invention, the ozone content in the mixture of gases leaving the ozone generator falls within the range of 200 to 400 ppm. Surprisingly, the present inventors have found that this level of ozone, which is significantly lower than the ozone levels typically used to treat water, is adequate to successfully suppress growth of microorganisms in the water being treated and to kill micro-organisms in the water.

In some embodiments of the present invention, an amount of 8-10 litres of water Ois treated with the gaseous mixture of air and ozone that is supplied at a flow rate of from 500 O to 1500 cm 3 /minute. Treatment times are suitably at least one minute, more preferably at least IND two minutes, even more preferably at least 5 minutes.

N 10 The air supply means may supply pressurised air supply means may supply pressurised air to the ozone generator. In this embodiment, the air supply means may be an air pump or an air compressor. The air pump or air compressor may be connected to the ozone generator by appropriate conduits or piping.

The injection means for injecting the gaseous mixture of air and ozone into the chilled water reservoir may include a pressurised diffuser having an outlet in the chilled water reservoir, said pressurised diffuser receiving gaseous ozone from the ozone generator.

Suitably, the pressurised diffuser creates a bubble column within the chilled water reservoir.

This is useful in that the bubble column causes agitation of the water in the chilled water reservoir, which ensures that all of the water in the chilled water reservoir is adequately mixed with ozone.

The chilled water reservoir may include a vent for venting to the atmosphere.

The vent is provided so that excess gas supplied to the chilled water reservoir can be vented from the chilled water reservoir. Suitably, the vent is provided with a microbial filter. In this fashion, microbial contamination cannot occur by microbes travelling down through the vent.

The vent may be a pressure equalisation vent. The vent may be operative to cause the chilled water reservoir to operate at a temperature that is above atmospheric pressure. In this way, atmospheric air is unlikely to be drawn into the chilled water reservoir. The present inventor has found that supplying the gaseous mixture of air and ozone into the chilled water reservoir washes the exposed internal walls, fittings, lid and seals of the reservoir before venting to atmosphere. The advantages are that all exposed components within the tank are disinfected by contact with the ozone and the bio-film growth of bacteria on exposed surfaces not covered by liquid contents is arrested.

-7- The water dispensing unit in the present invention may be further provided with Cat least one return check-valve between the chilled water reservoir and the ozone generator.

This assists in ensuring that back siphoning of contents of the chilled water reservoir to the ozone generator does not occur. Suitable non-return check-valves will be well known to persons skilled in the art and need not be described further.

The water dispensing unit may further include a flow path between the ozone Ogenerator and the chilled water reservoir that is arranged in such a manner so as to create an air Olock between the ozone generator and the chilled water reservoir when positive pressure in the I ozone supply line is reduced or terminated.

r 10 In other embodiments, the water dispensing unit of the present invention may also include a hot water reservoir. The hot water reservoir may receive water that has been treated with the mixture of air and ozone from the cold water reservoir. Alternatively, the hot water reservoir may also receive the mixture of air and ozone from the ozone generator in an analogous fashion to the chilled water reservoir.

In a second aspect, the present invention provides a method for treating water in a water dispensing apparatus including a chilled water dispenser, the method comprising passing air through an ozone generator to partially convert oxygen in the air to ozone to form a mixture of air and ozone and injecting the mixture of air and ozone into the chilled water reservoir.

In some embodiments of the method of the present invention, the ozone content in the mixture of gases leaving the ozone generator falls within the range of 200 to 400 ppm.

Surprisingly, the present inventors have found that this level of ozone, which is significantly lower than the ozone levels typically used to treat water, is adequate to successfully suppress growth of micro-organisms in the water being treated and to kill micro-organisms in the water.

In some embodiments of the method of the present invention, an amount of 8-10 litres of water is treated with the gaseous mixture of air and ozone that is supplied at a flow rate of from 500 to 1500 cm 3 /minute.

In other embodiments, the mixture of air and ozone is added to the water at a rate of from 50 to 200 cm 3 /minute/litre of water. Treatment times are suitably at least one minute, more preferably at least two minutes, even more preferably at least 5 minutes.

BRIEF DESCRIPTION OF THE DRAWINGS

O

Figure 1 shows a schematic diagram of a water dispensing unit in accordance with an embodiment of the present invention.

_DETAILED DESCRIPTION OF THE DRAWINGS The drawings attached to this specification have been provided for the purpose of illustrating preferred embodiments of the present invention. Thus, it will be understood that the present invention should not be considered to be limited to the features as shown in the accompanying drawings.

Figure 1 shows a schematic diagram of a water dispensing unit in accordance with an embodiment of the present invention. It will be appreciated that the water treatment apparatus shown schematically in Figure 1 will typically be enclosed in a cabinet or other aesthetically pleasing enclosure. This cabinet or other enclosure is not shown in Figure 1.

The water dispensing apparatus shown in Figure 1 is of the type in which water is condensed from the atmosphere, with the condensed water subsequently being treated before being received in the water storage reservoirs. Therefore, the apparatus shown in Figure 1 includes a condenser, shown schematically at 10, which condenses water from the atmosphere.

The condensed water is collected and sent via pipeline 12 to a condensed water storage tank 14. Condensed water storage tank 14 includes a float valve 16 that operates to control the operation of the condenser 10. When the water level in storage tank 14 falls below a preset level, float valve 16 sends a signal to turn on the condenser 10 to thereby condense water from the atmosphere. If the water level in tank 14 rises above a preset level, the float valve 16 sends a signal to turn off the condenser The tank 14 has an outlet connected to conduit 18. Pump 20 is used to cause water to flow from tank 14 to second storage tank 22. Second storage tank 22 includes a float valve 24 that is used to control the water level in tank 22. When the water level in tank 22 falls below a preset level, float valve 24 sends a signal to pump 20 to cause water to flow from first tank 14 to second tank 22. When the water level in second tank 22 exceeds a preset level, float valve 24 sends a signal to turn off pump O The water in second water tank 22 flows via pump 24 to the water treatment Ssystem 26. Water treatment system 26 includes a sedimentation filter 28, a pre-carbon filter d 30, an ultrafiltration filter 32 and a post carbon filter 34. Filters 28, 30, 32 and 34 are connected in series so that the water sequentially passes through each one. The sedimentation filter 28 removes large particles. The pre-carbon filter 30 removes organic molecules and heavy metals from the water. The ultrafiltration filter desirably has pore sizes down to 0.01 microns and acts to remove bacteria, protozoa and some viruses. Post carbon filter 34 acts to remove any remaining organic molecules, heavy metals and the like.

IDThe water treatment system 26 also includes a UV chamber 36. In UV chamber 36, water is exposed to ultraviolet light to inactivate any micro-organisms that pass through ultrafiltration filter 32.

The water leaving UV chamber 36 passes via conduit 38 to a chilled water reservoir 40. Chilled water reservoir 40 is suitably cooled to a temperature of between 2°C and 7°C by use of any known refrigeration apparatus. Chilled water reservoir 40 includes a level control 42 to control the level of water in that reservoir. Reservoir 40 includes a first outlet 44 that is connected to a hot water reservoir 46 such that water from the chilled water reservoir passes into the hot water reservoir. Chilled water reservoir 40 also includes a second outlet 48 that is connected to a dispensing tap 50 for dispensing chilled water therefrom.

Similarly, hot water reservoir 46 includes an outlet 52 that is connected to a dispensing tap 54 for dispensing hot water therefrom.

The chilled water reservoir 40 is suitably made from food grade stainless steel.

It is suitably made such that the reservoir 40 is seamless. Furthermore, the reservoir is sealed except for the various inlets and outlets shown in Figure 1.

The water dispensing unit further includes an ozone generator 56, which is a corona discharge ozone generator. An air pump 58 pumps atmospheric air through conduit into ozone generator 56 to thereby generate a mixture of ozone and air. This mixture suitable contains around 200 to 400 ppm ozone. The mixture of ozone and air generated in ozone generator 56 is a pressurised mixture. The mixture of ozone and air from ozone generator 56 travels via conduit 62 and through a non-return check valve 64 and via conduit 66 into the chilled water reservoir 40. The outlet of conduit 66 is positioned in the lower part of chilled water reservoir 40. The end of conduit 66 is provided with a known pressurised diffuser which r O creates a bubble column of ozone and air in the chilled water reservoir 40. This causes good C mixing between the water in reservoir 40 and the mixture of air and ozone to ensure that the d ozone in the mixture disinfects the water in reservoir SReservoir 40 is also provided with a vent 68, which acts to vent excess gas from chilled water reservoir 40 (it being appreciated that chilled water reservoir 40 is a largely sealed reservoir. Vent 68 includes a microbial filter 70 that is effective to prevent any microorganisms gaining ingress to the chilled water reservoir 40 via vent 68.

In operation of the water dispensing unit shown in Figure 1, a mixture of pressurised air and ozone is supplied into the sealed and vented chilled water storage reservoir C 10 40. The ozone acts to disinfect and sterilise the water held in chilled water reservoir 40. The ozone also washes the exposed internal walls, fittings, lid and seals of the chilled water reservoir 40 before venting to the atmosphere via the pressure equalisation vent 68 fitted with microbial filter 70. As a result, all exposed components within the tank are disinfected by the ozone and any biofilm growth of bacteria on exposed surfaces not covered by the liquid contents is arrested. In poreferred embodiments of the present invention, the particular levels of ozone used in the mixture of air and ozone added to the reservoir (200 to 400 ppm) are significantly lower than previously thought suitable for killing micro-organisms. However, the inventors have surprisingly found that this level of ozone can kill micro-organisms. As the ozone levels are low, concerns regarding the safety or deleterious effects of adding ozone to water adverse taste outcomes) are minimised.

Furthermore, as the water that is supplied to the hot water reservoir 46 comes from the chilled water reservoir 44, that water has been treated with the mixture of air and ozone, thereby ensuring sterility of that water. Further, the high temperatures in the hot water reservoir 46 maintains stability.

The present invention provides a water dispensing unit that assures good quality water being dispensed. The distribution and concentration of ozone gas in the chilled water reservoir occurs in such a manner so as to provide for a safe, chemical-free, disinfection system harmless to both the hot or refrigerated contents of the water storage reservoirs and to any consumer of the dispensed output of the hot or refrigerated contents of the storage reservoirs.

In some embodiments of the present invention, the ozone generator may be provided with an electrical timing circuit or switching mechanism arranged such that the ozone -11 generator may be activated at a predetermined or variable time and for a predetermined or variable duration.

As a further feature of the present invention, the conduit 66 that supplies the pressurised mixture of air and ozone to the chilled water reservoir 40 is arranged so that the (,i flow path of pressurised air containing ozone occurs in such a manner as to create an air lock between the atmosphere and the contents of the reservoir 40 when positive pressure in the Oair/ozone supply is reduced or terminated. This assists in preventing microbial contamination Ogetting into the chilled water reservoir 40 via the ozone feed lines when the ozone generator is Sinoperative.

The present invention provides a further level or consumer and operator protection if any of the bacteriological filter systems, ultraviolet flow chamber systems, components, or mechanical systems in a water dispensing unit fail. In the case of such failure, three basic mechanisms govern the occurrence of pathogenic micro-organisms: The microbes break through the treatment process from the source liquid or water supply; Any microbes regrow quickly from very low levels, typically in biofilms; or the organisms result from a recontamination of the treated water or liquid within the water dispensing unit itself.

The present invention provides a final barrier which can duplicate any or all of the bacteria removal capabilities of any succeeding processing steps. In this way, the present invention provides a sufficient back up system to permit continuous operation of the water dispensing unit in the face of any normal or abnormal mechanical or component failure, or in any failure in carrying out manufacturer specified equipment servicing at correct intervals.

Although the embodiment shown in Figure 1 relates to a water dispensing unit which sources water from condensation from the atmosphere, the source of water may be from bottled water (in which case the water treatment system 26 may be dispensed with).

Alternatively, the water dispensing unit may receive its water supply from a municipal water supply.

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ID

O It will also be appreciated that the particular components of the water treatment system 26 may be varied from that shown in Figure 1.

SThe amount of ozone supplied to the chilled water reservoir can vary between Srelatively wide limits, with suitable ozone concentrations being from 0.000001 to 400ppm.

The various components of the water dispensing unit are suitably made from materials which are acceptable for use in food manufacture and suitably resistant to ozone.

Examples include glass, PTFE coated materials and stainless steels (300 series and above).

IsN Those skilled in the art will appreciate that the present invention may be subject to variations and modifications other than those specifically described. The present invention encompasses all such variations and modifications that fall within its spirit and scope.

Claims (4)

1. A water dispensing apparatus including a chilled water dispenser, the apparatus comprising a chilled water reservoir, a water outlet in fluid communication with the chilled water reservoir for dispensing water therefrom, flow control means for controlling the flow of water through the water outlet, an ozone generator for treating air passed to the ozone generator to partially convert oxygen in the air to ozone to form a mixture of air and ozone, and Sinjection means for injecting the mixture of air and ozone into the chilled water reservoir.

2. A water dispensing apparatus as claimed in claim 1 wherein the ozone 10 content in the mixture of gases leaving the ozone generator falls within the range of 200 to 400 ppm.

3. A water dispensing apparatus as claimed in claim 1 or claim 2 wherein the mixture of air and ozone is supplied to the water at a rate equivalent to treating an amount of 8-10 litres of water with the gaseous mixture of air and ozone that is supplied at a flow rate of from 500 to 1500 cm 3 /minute.

4. A method for treating water in a water dispensing apparatus including a chilled water dispenser, the method comprising passing air through an ozone generator to partially convert oxygen in the air to ozone to form a mixture of air and ozone and injecting the mixture of air and ozone into the chilled water reservoir, wherein the ozone content in the mixture of gases leaving the ozone generator falls within the range of 200 to 400 ppm. A method as claimed in claim 4 wherein the mixture of air and ozone is added to the water at a rate of from 50 to 200 cm 3 /minute/litre of water. DATED this 2 0 th day of December 2006 Konia Australia Pty Ltd By their Patent Attorneys CULLEN CO.