WO2011055133A2

WO2011055133A2 - Water purification apparatus and method

Info

Publication number: WO2011055133A2
Application number: PCT/GB2010/051737
Authority: WO
Inventors: Nigel Emery; Alan Denton Mortimer
Original assignee: Veolia Water Solutions & Technologies Support
Priority date: 2009-11-06
Filing date: 2010-10-15
Publication date: 2011-05-12
Also published as: WO2011055133A3; GB0919477D0

Abstract

A water purification apparatus comprising at least: (a) one or more water purification components (40, 43, 44, 45, 46) and water pathways (26, 28) to provide an ultrapure purified water stream from one or more water outlets, the purified water stream preferably having a conductivity of less than lμS/cm; and (b) one or more UV LED units (30,30a) located around at least one of the water pathways, a point of dispense of one of the water outlets, or both. The relatively small size of UV LED units (30, 30a) makes it possible to use them to provide local irradiation at various locations in and around a water purification apparatus, and particularly at a point of dispense (i.e. where the purified water leaves the apparatus), to prevent/inhibit microbial contamination at the air/water interface, during dispense, more particularly during periods of non-dispense.

Description

Water Purification Apparatus and Method

The present invention relates a water purification apparatus and method comprising one or more UV LED units and optionally photoreactive material, particularly, but not exclusively for providing purified laboratory water.

Water purification systems and apparatus for use in laboratories and healthcare facilities are well known. Generally they involve the reduction and/or removal of contaminants and impurities to low levels. They typically contain a variety of technologies that remove particles, colloids, micro-organisms, ionic species and organic substances and/or molecules. The control of micro-organisms in water purification systems and apparatus is a challenge to the designers of such equipment to produce pure water. Within the equipment, several techniques/technologies are utilised to control or eliminate micro-organisms and/or biologically active cell products and debris such as endotoxins and nucleases. These technologies can include reverse osmosis, ultrafiltration, micro-filtration, fluorescent UV irradiation, etc. In addition to these, recirculation and sanitisation techniques are also employed.

Despite these various activities, contamination of pure, purified or ultrapure water by opportunist organisms is frequently experienced. In many instances, such organisms access the purified water via the air/water interface at the apparatus outlet, as this is usually where the purified water comes into contact with the local environment. This contamination can reside in the outlet but could also attach and grow on the walls of the outlet and may also be able to back contaminate the whole unit by passage or growth back through valves and filters and spread through the unit via the flow paths.

In order to prevent or minimise this contamination, a number of techniques have been employed, such as a 'point of use' filter with a pore size in the sub-micron range designed to prevent passage of micro-organisms.

Other techniques include placing the purified water dispenser in a heated holster, so that during periods of non-use, the environment local to the water dispenser is maintained at an elevated temperature in order to inhibit/prevent growth of micro-organisms. Whilst effective, this technique has the disadvantage of being energy-expensive to maintain the required temperature. It also heats the water in the water recirculation system, which is undesirable for various reasons.

Another technique used for this purpose is the irradiation of the dispense nozzle with short wavelength UV from a separate UV light source.

Although beneficial, the cost of this method is also high due to the use of expensive plastics required that do not degrade in the short wavelength UV spectrum, but which can still transmit a reasonable portion of the UV light generated.

It is an object of the present invention to provide a water purification apparatus which has an easier and more adaptable UV light source available at lower cost and with smaller dimensions.

According to one aspect of the present invention, there is provided a water purification apparatus comprising at least: (a) one or more water purification components and water pathways to provide an ultrapure purified water stream from one or more water outlets, the purified water stream preferably having a conductivity of less than 1 pS/cm; and

(b) one or more UV LED units located around at least one of the water pathways, a point of dispense of one of the water outlets, or both.

The relatively small size of UV LED units makes it possible to use them to provide local irradiation at various locations in and around a water purification apparatus, and particularly at a point of dispense (i.e. where the purified water leaves the apparatus), to prevent/inhibit microbial contamination at the air/water interface, during dispense, more particularly during periods of non-dispense. The use of ultraviolet light in the treatment of water for decomposing organic compounds or substances in water is well known in the art.

Generally, ultraviolet light is able to decompose many organic compounds and substances that are contained or are residues in generally available water, by oxidising them to form ionic species.

Conventional ultraviolet light sources are also well known in the art, and typically involve emitting ultraviolet light from one or more U V longitudinal fluorescent tubes in an area or space through which the water passes. However, UV longitudinal fluorescent tubes are cumbersome and delicate, and are not easily adaptable for use in other locations around or in a water purification apparatus, in particular in and around one or more water outlets and points of dispense. The present invention takes advantage of the adaptability of UV LED units to be more flexible in their location, being smaller and more robust than fluorescent tubes, and therefore be practically useable in and around any relevant part of a water outlet to prevent or minimise contamination by organisms in the local environment of the purified water provided or to be provided by the water purification apparatus, the walls of the water outlet, the water purification unit, etc.

The decontamination or germicidal effect provided by the or each UV LED unit is useable over any time period or periods, ranging from being permanently active, generally when the water purification apparatus is active, to intermittent use such as during purified water dispense, and/or intermittently during non-dispense periods of the apparatus. The invention is not limited by the time of operation of the or each UV LED unit.

For example, there could be a UV LED unit located around the point of dispense of a water outlet which is operational intermittently, usually periodically, during periods of non-dispense of purified water, and automatically active during periods of water dispense.

There could be a UV LED unit located around other water parts or passages in or through which water passes, particularly intermittently and/or which are inactive when water is not being dispensed. This can involve 'stagnant areas', more likely to give time and space for microbial activity and build up. For example, just after any valve when not dispensing, especially after an outlet valve, or at locations in or around a water storage area or tank, in particular in corners thereof, etc.

Such UV LED units could be provided separately or integrally with such parts, components, etc.

Thus, the present invention extends to a component or part of a water purification apparatus as defined herein, wherein the component comprises one or more of the following: pumps, meters, oxidisers, de- ionisers, valves, pipes, piping, drains, controllers, control units, control mechanisms, outlets, taps, reservoirs, recirculation loops, filters and membranes; having one or more UV LED units therewith, preferably integrally therewith.

The activity of the or each UV LED unit may be controlled manually, automatically by the water purification apparatus, or a combination of both. For example, the or each control for the dispense of purifying water from a water outlet may include a manual activator such as a button so that a user is able to control activation of a UV LED unit during dispense of a purified water stream, and optionally control its activation in advance of and/or after such dispense. Control may also be triggered on replacement of a moveable dispenser, such as a handset, into its locating point, such as a holster, integral to the water purification unit.

The shape, size and design of the or each UV LED unit is not limited in the present invention, and the adaptability of LEDs in general is such that the or each UV LED unit can be added separately and/or be integral with a part of the water purification apparatus to provide direct and immediate UV radiation thereto. Thus, the use of UV-radiation from UV LEDs avoids the need for providing optical transmission of UV radiation from a source separate from the place of use, and avoids the need for considering specialised materials through which UV-radiation from previous UV sources had to pass. This significantly simplifies the use of UV-radiation in water purification apparatus, increasing the flexibility of the use of UV- radiation, particularly at and around one or more water outlets to prevent and/or minimise contamination of such outlets at their point of contact with the local environment, which includes contamination by users (usually by touch) as well as air-borne organisms. According to another embodiment of the present invention, the apparatus includes at least one photoreactive material able to provide hydroxyl radicals upon exposure to UV radiation from one or more of the UV LED units of the apparatus.

The photoreactive material may be any suitable material, such as titanium dioxide, ΤΊΟ2. Photoreactive materials are known, for example as described in US 6117337 and US 7396459 B2.

Thus, to further enhance the effectiveness of the UV LED unit, a piece, plate, sheet, lining or other area of titanium dioxide (T1O2), tin dioxide

(Sn02), and/or another anti-microbial material, can be placed on the interior surface of the valve, outlet, tank or other water pipework, etc. near to the UV LED unit. Exposure of the T1O2 or similar coating to the UV radiation induces catalytic oxidation, releasing hydroxyl (OH^~) radicals that effectively inactivate aqueous bacteria and other pathogens. In particular, a Ti0₂ lining increases the antimicrobial activity near the walls of irregularly shaped vessels when activated by the UV light. The hydroxyl radicals can also be provided into pipework or tubing that connects the water components of the water purification apparatus. The hydroxyl radicals, having super oxidative properties, reduce or eliminate

microorganism and biofilm build-up. The hydroxyl radicals also break up harmful chemical compounds that may be in the water supply incidentally.

Purified water provided by the water purification apparatus of the present invention is created by the reduction and/or removal of any or one or more of the contaminants and impurities in a supply water stream, by the water purification components of the apparatus. This can involve the reduction and/or removal of one or more of the following: particles, colloids, bacteria, micro-organisms, microbial by-products, ionic species, organic substances and organic molecules.

Preferably, at least one of the water purification components is a de- ioniser, and where there are more than one water purification components, they include at least one de-ioniser, and optionally one or more

conventional oxidisers such as an ultraviolet light emitter. The or each oxidiser can be provided as a distinct component, typically a separable component such as a replaceable cartridge, having an ultraviolet emitter therein around which the water stream passes from an inlet to an outlet. The purification of water in the present invention may involve one or more oxidisers, being in series, parallel or both.

Ionic species in the feedwater (and those created by any oxidiser(s)) are generally removed from the water stream to provide purified water by the use of one or more de-ionisers such as ion-exchangers and reverse osmosis units. Many types and forms of de-ionisers are known in the art, and include, but are not limited to, one or more of the following;

(electro)deionisation apparatus or units, reverse osmosis (RO) units or apparatus, resins and zeolites. The action and operation of de-ionisers is well known in the art, and they are not further described in detail herein.

A water purification apparatus or unit may comprise a plurality of de- ionisers, including one or more "pre-treatment" de-ionisers upstream of any oxidiser, as well as one or more de-ionisers downstream of any oxidiser.

In general, the water purification apparatus of the present invention at least comprises: a water inlet, a pump, a de-ioniser, and a water outlet having at least one point of dispense for dispense of the purified water from the outlet.

At least one water outlet of the apparatus of the present invention comprises a point of dispense of purified water, either for direct collection by a user or for provision to one or more other apparatus or systems. Such water outlet(s) may include a nozzle, spout, tip or other such device to provide a point of dispense, and the invention does not specify between these: the term "nozzle" is used herein to cover all such terms.

Thus, at least one of the water outlets of the water purification apparatus of the present invention may include at least one nozzle and/or may include at least one valve. According to another embodiment of the present invention, there is at least one UV LED unit providing UV-radiation to at least one nozzle or at least one valve or both.

According to one embodiment of the present invention, the apparatus comprising a housing, a handset, and at least one water outlet from the handset. The handset may be moveable between a suspended position on the housing and a suspended position beyond the housing, preferably in a hand-holdable position by a user. At least one control of the purification of the water in the housing could be operative on the handset, which handset is useable either in its supported position on the housing or in its suspended position beyond the housing, whichever is most convenient to the user. The suspended position of the handset may allow the handset to be in a 'free' position in general. Alternatively, it may be desired and/or required that the handset in its suspended position is in a hand-holdable position by a user.

The housing of a water purification apparatus for the present invention may be of any suitable shape, size and design. The housing may be adapted to be self-supporting, and/or be able to be mounted on a wall or other suspended position. The housing preferably includes all the physical water purification components for providing an ultrapure purified water stream from the water purification apparatus, which physical components provide the reduction and/or removal of contaminants and impurities as discussed herein.

The housing may also include a holster for the handset. The holster may have any suitable size, shape and design, usually being complementary to the shape, size and design of the handset. For example, the holster may have one or more optionally tapering sleeves, arms, grooves or ridges, which locate with corresponding surfaces, arms, grooves or ridges on or around the handset. Such a holster could provide the supported position of the handset on the housing.

According to one embodiment of the present invention, the holster includes one or more UV LED units adapted to prevent and/or minimize contamination of the point of dispense of the water outlet such as at the nozzle of the handset with the local environment by emitting UV radiation onto the nozzle surfaces and/or air water interface at the point of dispense at the end of the nozzle.

Any handset may be integral with the housing by being permanently connectable therewith. In one embodiment of the present invention, there is provided a neck, preferably a flexible neck, between the housing and the handset. The neck preferably provides the ability of the handset to be moveable between its supported position on the housing and its

suspended position beyond the housing. The flexible neck may comprise one or more conduits, optionally being one or more water conduits and one or more electrical conduits. Where the handset includes a purified water dispense, or point of use, the neck preferably comprises at least one water conduit. Where the handset includes a water pathway for the purified water, such that non-dispensed purified water can be returned to the housing, the neck preferably comprises two or more water conduits, generally being a first conduit for flow of purified water into the handset, and a second water conduit for return flow of non-dispensed purified water back to the housing. The flexible neck may also comprise at least one electrical conduit able to provide electrical communication between the or each water purification control on the handset and the one or more water purification components in the housing. Preferably, the holster or the handset or both includes a handset location identifier to identify the location of the handset in the holster. For example, the holster and/or the handset may include a mechanism or switch, such as an electrical, magnetic, etc. contact(s), to identify or confirm the action of location or re-location of the handset in the holster. This mechanism could allow control of the UV LED unit by, for example, initiating the UV

LED unit for a set time period, intermittently or continuously, on re-location of the handset within the holster.

According to another embodiment of the present invention, the handset, the flexible neck or both may comprise one or more UV LED units around a water pathway therein adapted to prevent and/or minimize

contamination of water passing therethrough, especially recirculated water during periods of non-dispense of purified water from the water outlet(s). Purified water may be dispensed from the water purification apparatus from one or more further and/or different outlets or dispense points, optionally via one or more other dispense points on the housing or remote therefrom. Any handset as described hereinbefore may include a display. The display may have any suitable size, shape and configuration, and generally comprises one or more display portions and/or cells, able to provide visual information to a user. Such information may include one or more figures and/or parameters concerning the operation of one or more parts or components of the water purification apparatus, including at least one UV LED unit. Such information could include one or more readings and/or measurements of a parameter such as purity, conductivity, restistivity, flow, speed, temperature of the water purification apparatus and/or of one or more of the water purification components in the housing. This could include the efficiency, activity and/or operation of at least one UV LED unit, and the purification effect provided thereby.

According to another embodiment of the present invention, at least one water pathway of the water purification apparatus comprises a water recirculation line. One or more UV LED units may be located around such a water pathway, to assist in the maintenance of the water purification during recirculation of water within the apparatus during periods of non- dispense. At least one, generally the or each, UV LED unit useable in the present invention comprises one or more UV LEDs able to emit UV radiation at a wavelength able to provide a germicidal effect. Such wavelengths may be in the range 400-1 OOnm, preferably <300nm, such as at a wavelength of 280-285nm, but including shorter wavelengths such as <200nm. Such units are available from Sensor Electronic Technology, Inc. of Columbia, SC, USA, with wavelengths of such as 240nm, 200-255nm and 280nm.

According to another embodiment of the present invention, at least one user interface of the water purification apparatus includes one or more water purification controls able to operate at least one UV LED unit.

According to a second aspect of the present invention, there is provided a method of cleaning a water purification apparatus as defined hereinbefore and comprising one or more UV LED units located around at least one of the water pathways, one of the water outlets, or both, wherein the at least one UV LED unit UV-radiates the at least one of the water pathways, the point of dispense of one of the water outlets, or both, to clean same. Preferably, the at least one UV LED unit UV-radiates intermittently or non- continuously at least one of the water pathways, a point of dispense of one of the water outlets, or both. Such radiation may be pre-determined and/or based on one or more of the parameters including time, sensor levels, temperature, pump activation or the like.

According to one embodiment, the water purification apparatus includes a handset and a housing, and the method of the present invention includes at least one UV LED unit being activated following variation of the location of the handset relative to the housing. For example, the housing may include a holster for the handset, and location of the handset in the holster could activate a UV LED unit in one of the handset or the holster or both, possible by activation of a handset location identifier as described hereinabove. The term water purification apparatus includes a water distribution apparatus which may comprise any number of purified water distribution components, as well as other devices, parts, lines, etc, including but not limited to one or more of the following: pumps, meters, (additional or supplementary) oxidisers and/or de-ionisers, outlets, tanks, valves, drains, controllers, taps, filters, membranes.

Such water distribution apparatus are generally units connected to water purification apparatus to distribute the purified water stream provided therefrom to one or more separate, usually remote, locations. Thus, they are generally independent and/or mobile units having one or more water outlets and dispense points. They are intended to provide a purified water stream only, such stream not being in combination with any other substance or compound. The term "user" as defined herein relates to a person (being singular or plural) desiring to obtain a dispense of the purified water stream from the water purification apparatus for subsequent use of the purified water in an operation or process. The water purification apparatus of the present invention may comprise any number of water purification components, as well as other devices, parts, lines, etc, including but not limited to one or more of the following: pumps, meters, oxidisers, de-ionisers, valves, sensors, drains, controllers, control units, control mechanisms, taps, reservoirs, recirculation loops, filters and membranes. One or more of such components may be integral with the water purification apparatus, such as a pump, and one or more of such components may be separable from the water purification apparatus, such as an ion-exchange cartridge. Water purification apparatus are known in the art, and are generally intended to provide purified water, preferably as a purified water stream, having a conductivity of less than 1 pS/cm, preferably less than 0.1 pS/cm, more preferably less than 0.067 pS/cm, at 25°C. This can be equated to the purified water stream having a resistivity of at least 1 ΜΩ-cm, preferably at least 10 ΜΩ-cm, more preferably at least 15 Ω-cm.

Additionally, purity specifications can be made for organic species to content levels of less than 500ppb of total organic carbon (TOC), preferably less than 50ppb; bacteria to levels less than 100 colony forming units (cfu) per millilitre, preferably less than 1 cfu/ml; and for dissolved oxygen and/or particles.

Such water purification apparatus generally only provide up to 1000 litres of purified water per hour, such as up to 5 l/min. Such water purification apparatus are generally 'stand alone' units, generally only requiring connection to nearby water and electricity supplies to be operable. Thus, they are generally independent and/or moveable units operating in or at a specific location such as a laboratory. Preferably, at least the majority of the purification actions or processes occur within a housing. They are intended to provide a purified water stream only, such stream not being in combination with any other substance or compound.

The water purification apparatus may comprise a plurality of ion- exchangers, including one or more "pre-treatment" ion exchangers upstream of any oxidiser, as well as one or more ion-exchangers downstream of any oxidiser.

The dispense of at least a portion of the purified water from the water purification apparatus can be provided through any form or type of outlet or outlets, optionally being co-ordinated or separate.

The water purification apparatus may have a dispense mode or other such form of operation, and a recirculation mode. Preferably, the or each point of dispense of the purified water involves at least one valve, more preferably operable between a dispense position and a recirculating position. One or more valves may also provide control over the volume and/or rate of flow of the purified water at the dispense. The movement of water through a water purification apparatus is generally provided by the use of one of more pumps known in the art, and the nature and operation of a pump is not further discussed in detail herein.

The present invention encompasses all combinations of various embodiments or aspects of the invention described herein. It is

understood that any and all embodiments of the present invention may be taken in conjunction with any other embodiment to describe additional embodiments of the present invention. Furthermore, any components of an embodiment may be combined with any and all other components from any of the embodiments to describe additional embodiments.

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a front view of a first water purification apparatus according to one embodiment of the present invention;

Figure 2 is a schematic layout of components for the water purification apparatus of Figure 1 ;

Figure 3 is a cross-sectional view of the end of the outlet nozzle of Figure 2; Figure 4 is a view of Figure 3 with photoreactive material therewith;

Figure 5 is a cross-sectional view of a valve in the apparatus of Figure 2;

Figure 6 is a schematic diagram of a second water purification apparatus according to an embodiment of the present invention having a water reservoir.

Referring to the drawings, Figure 1 shows a first water purification apparatus 10 comprising a housing 12 and a handset 16. Within the housing 12 are one or more water purification components such as those described hereinabove. Such components may be integral and/or separable from the housing 12.

The water purification apparatus 10 is typically intended to be located on or near a work bench, optionally supported thereby or self-supporting. A water purification apparatus may include one or more water inlets, generally from a single source such as a tap or other potable water supply, and to provide one or more water dispense points. Figure 2 shows a single water dispense point with the water purification apparatus 10 by way of example only. Water dispense points can be movable relative to the housing 12, and/or located in remote locations such as through water supply piping or conduits such as a ring main to one or more remote locations, such as a separate room, workbench or laboratory. Figure 2 shows a number of possible components within the housing 12, such as: a water inlet 26 passing into a reverse osmosis unit 40, generally having a reverse osmosis cartridge therein, towards a tank 41. Water from the tank 41 can be pumped around the water purification apparatus 10 by a pump 42, followed by one or more water purifying components such as an organic absorption cartridge 43, an ion exchange cartridge 44, and a membrane micro-filtration cartridge 45, followed by a line cell 46 adapted to provide information to a controller (not shown) prior to passage into the handset 16. The operations of water purification components are well known to those skilled in the art, and are generally intended to reduce and/or remove contaminants and impurities in water provided from the water input 26, so as to provide a purified water stream from the water dispense point. Water purification components can include physical, magnetic, electrical and/or light-based components in any arrangement known in the art.

Figure 1 shows the handset 16 connected to the housing 12 via a flexible neck 14 with an interface 1 . The outlet nozzle 34 of the handset 16 provides the actual point of dispense of the water outlet from the handset 16. Figure 2 shows the handset 12 having an internal valve 39 able to control the dispense of purified water from the handset 16 through the outlet nozzle 34, optionally controlled by a valve controller such as a button 22 at an opposing end of the handset 16 from the outlet nozzle 34. Figure 2 also shows a recirculation line 28 able to recirculate purified water back to the tank 41 from the handset 16 when not required or not being dispensed in a manner known in the art. The nature and operation of a recirculation line with or in connection with a water purification apparatus is well known in the art, and generally allows the water purification apparatus to maintain a level or quality of water purification during times of non-dispense, avoiding water in the water purification apparatus becoming static, and therefore possibly stagnant as known in the art.

The outlet nozzle 34 of the handset 6 is locatable within a recess 17 of a holster 18 attached to and/or integrally formed with the housing 12.

Around the recess 17 are located a plurality of UV LEDs 30 provided in the form of one or more UV LED units and able to provide UV-radiation to the outlet nozzle 34 when it is located in the recess 17, in particular the air/water interface at the end of the outlet nozzle 34.

The operation of the UV LEDs 30 may be periodical and/or intermittent, such as for example only during the location of the outlet nozzle 34 in the recess 17, optionally with an additional time period such as a few minutes after placement of the outlet nozzle 34 into the recess 17; or during operation of the button 22; or for a pre-determined time period after operation of the button 22, such as a few minutes after the end of a water dispense from the handset 16; or otherwise without limitation, such as permanently.

One or more of the above operations could be initiated or otherwise activated by a handset location identifier, such as corresponding electrical solenoids or contacts 35a and 35b on or in the holster 18 and handset 16 respectively, whose proximity as the handset 16 is located or re-located into the holster 18 activates a switch or the like to provide said

operation(s), particularly after the end of a water dispense when remaining water in the outlet nozzle 34 may remain static for a time in the nozzle 34, and/or periodically thereafter during continuing non-use of the handset 16.

Figure 2 also shows the location of three UV LEDs 30a which could be provided in the form of a UV LED unit alongside the recirculation line 28. This arrangement can provide UV-radiation to recirculated purified water passing through the recirculation line 28 so as to assist decontamination of purified water after passing through the handset 16. Such UV LEDs 30a may be located within the flexible neck 14 between the handset 6 and the housing 12, and/or within a static part of the recirculation line 28 within the housing 12. Such is the flexible use of UV LEDs. Similarly UV LEDs may be located in other lines such as from the tank, 41 to the pump, 42, or from the line cell, 46 to the valve, 39.

Figure 3 shows an enlarged cross-sectional view of the end of the outlet nozzle 34 in Figure 2 having a central passageway 36 for the passage of dispensed water therethough. Based on another embodiment of the present invention, UV LEDs can be provided that are sufficiently small to also be formed singularly or as a multiple unit within the walls of the end of the outlet nozzle 34 around the central passageway 36, so as to provide direct UV-radiation into the dispensed water as it passes through the central passageway 36.

The UV LEDs 38 could be formed integrally with the outlet nozzle 34 to provide a component for the water purification apparatus 10 comprising one or more UV LEDs according to another embodiment of the present invention. Figure 4 shows a second enlarged cross-sectional view of the end of the outlet nozzle 34 shown in Figure 3, with the addition of a photoreactive strip 48 comprising a photoreactive material like titanium dioxide, according to another embodiment of the present invention. UV-radiation from the two UV LED units 38 can impact on the photoreactive strip 48 to create hydroxyl radicals from the dioxide, whose oxidative properties can further enhance oxidation of microbes and the like in the water being dispensed through the central passageway 36. Such free radicals can sanitise an area by convection, as well as the UV-radiation.

Figure 5 shows a valve assembly 50 for use in a path of any suitable line, pipeline or other pipe 52 that could be in any part of the water purification apparatus 10. The valve assembly 50 comprises a valve head 54 movable into and out of a valve seat 56 in a manner known in the art to control the flow of a liquid, generally water, passing through the pipe 52, and in particular in the restricted passageway 58 between the valve head 54 and valve seat 56, which restricted passageway 58 can be varied according to the height of the valve head 54 to change the flow rate through the valve assembly 50 in a manner known in the art.

When the valve assembly 50 is closed, water can remain stationary or static upstream and/or downstream thereof, and it is possible for microbial activity to begin in any static water. Thus, Figure 5 shows, according to another embodiment of the present invention, the location of two UV LED units 60a upstream of the valve assembly 50 and two UV LED units 60b downstream of the valve assembly 50 so as to UV-irradiate static water both before and after the valve assembly 50, particularly when it is closed.

Figure 5 also shows the two photoreactive strips 61a, 61 b like that shown in Figure 4, such that UV-radiation from the respective UV LED units 60a, 60b can impact on the photoreactive strips 61 a,b to create hydroxyl radicals from the dioxide material, whose oxidative properties can further enhance oxidation of microbes upstream and downstream of the valve assembly 50 as described above.

Indeed, Figure 5 is only one example of the numerous possible locations of UV LED units in and around a water purification apparatus, especially component inlets, outlets and parts with high surface areas where stationary or static water may exist, and more especially when any pump is not active in the apparatus to provide movement of the water therein. To minimise and hopefully prevent microbial activity in any such static water locations, UV LED units can be conveniently located in, around or otherwise next to or nearby such locations. Such UV LED units could be fitted, including retro-fitted, to existing components and apparatus, or be integrally formed during manufacture of such components and apparatus, without significant alteration to conventional manufacturing processes for such components and apparatus.

Figure 6 shows a further embodiment of the present invention based on a second water purification apparatus 62 having an inlet 64, one or more water purification components 66, and a holding reservoir or tank 68 able to hold purified water provided by the one or more purification components 66 in a holding location prior to dispense from an outlet 70. Figure 6 also shows a recirculation path 72 for recirculation of water during periods of non-dispense.

The holding tank 68 in Figure 6 may have one or more interior positions or locations or areas where water can be static. Such water may be static during periods of non-dispense, and/or also be static during water flow through the tank 68, particularly in one or more quiescent locations in the holding tank 68. It is known that holding tanks in water purification apparatus can include one or more such quiescent areas, possibly as a result of restrictions in the tank manufacturing process, which areas can quickly lead to microbial activity, etc.

Figure 6 shows the location of the a number of UV LED units 74 and associated photoreactive strips 76 in nominal positions, but which could be located, particularly integrally formed, at any location in or on the interior surface of the holding tank 68, so as to particularly focus on any quiescent areas therein.

Example 1 (dipped tips)

Two nozzles, usable as water outlets in a water purification apparatus such as that shown in Figures 1 and 2, and having an internal diameter 3.5 mm and outside diameter 6.0 mm, were immersed into a standard solution of water containing a bacterial level of approximately 4000 colony forming units (cfu)/ml so that water was held within the nozzle to a depth of 2.5mm. One of the nozzles was irradiated for 1 minute by a UVTOP270 TO39FW UV LED unit as supplied by Sensor Electronic Technology Inc, SC, USA; and the other nozzle was not irradiated. The two nozzles were then immersed and rinsed with 10 ml of sterile water to provide rinse water samples.

The two rinse water samples were then filtered through 0.2μηη membrane disc filters as supplied by mdi Advanced Microdevices Ltd, India, placed onto R2A agar plates and incubated at 27°C for 4 days. After 4 days the bacterial colonies were counted.

Results:- UV-irradiated - 0 colonies; Not irradiated - 127 colonies Example 2 (coated tips)

Two similar nozzles to those described above in Example 1 , and having internal diameter 3.5 mm and outside diameter 6.0 mm, were immersed into a standard solution of water containing a bacterial level of

approximately 4000cfu/ml so that water coated the nozzles to a depth of 2.5mm. One of the nozzles was irradiated for 1 minute by a UVTOP260 TO18FW UV LED unit as supplied by Sensor Electronic Technology Inc, SC, USA; and the other nozzle was not irradiated. The two nozzles were then immersed and rinsed with 10 ml of sterile water to provide rinse water samples.

The two rinse water samples were then filtered through 0.2μιτι membrane disc filters as supplied by mdi Advanced Microdevices Ltd, India, placed onto R2A agar plates and incubated at 27°C for 4 days. After 4 days the bacterial colonies were counted.

Results:- UV-irradiated - 0 colonies; Not irradiated - 13 colonies

The examples of the invention and of certain embodiments shown and described above illustrate the ability of UV LED units to be fitted into components and devices which may by design or necessity have a limited hygienic design, with dead or static zones or areas. The UV LED units are clearly effective in inhibiting microbial contamination on water outlet nozzles to prevent bacterial infection during periods of non-use of the water outlet.

It will be appreciated that although specific embodiments of the invention have been described herein for the purposes of illustration, various modifications may be made without deviating from the spirit of the scope of the invention.

Claims

1. A water purification apparatus comprising at least: (a) one or more water purification components and water pathways to provide an ultrapure purified water stream from one or more water outlets, the purified water stream preferably having a conductivity of less than 1 pS/cm; and (b) one or more UV LED units located around at least one of the water pathways, a point of dispense from one of the water outlets, or both.

2. A water purification apparatus as claimed in claim 1 wherein at least one of the water purification components is a de-ioniser.

3 A water purification apparatus as claimed in claim 1 of claim 2 wherein the water purification apparatus further includes at least one photoreactive material able to provide hydroxyl radicals upon exposure to UV radiation from one or more of the UV LED units of the apparatus.

4. A water purification apparatus as claimed in claim 3 wherein the photoreactive material is ΤΊΟ₂. 5. A water purification apparatus as claimed in any one of the preceding claims wherein at least one water outlet comprises a handset

6. A water purification apparatus as claimed in claim 5 further comprising a housing, and wherein the handset is moveable between a suspended position on the housing and a suspended position beyond the housing, preferably in a hand-holdable position by a user.

7. A water purification apparatus as claimed in claim 6 wherein the housing includes a holster for the handset, and the holster includes one or more UV LED units.

8. A water purification apparatus as claimed in claim 7 wherein the holster or the handset or both includes a handset location identifier to identify the location of the handset in the holster.

9. A water purification apparatus as claimed in any one claims 5 to 8 wherein the handset includes a water pathway for purified water. 0. A water purification apparatus as claimed in any one of claims 5 to 9 wherein the handset comprises one or more UV LED units.

11. A water purification apparatus as claimed in any one of the preceding claims wherein at least one of the water outlets includes at least one nozzle as the point of dispense.

12. A water purification apparatus as claimed in any one of the preceding claims wherein at least one of the water outlets includes at least one valve.

13. A water purification apparatus as claimed in claim 11 or claim 12 wherein at least one UV LED unit provides UV-irradiation to at least one nozzle or at least one valve or both.

14. A water purification apparatus as claimed in any one of the preceding claims wherein at least one water pathway comprises a water recirculation line. 15. A water purification apparatus as claimed in any one of the preceding claims wherein at least one UV LED unit comprises one or more UV LEDs able to emit UV radiation at a wavelength able to provide a germicidal effect. 16. A water purification apparatus as claimed in any one of the preceding claims wherein at least one water outlet includes one or more water purification controls able to operate at least one UV LED unit.

17. A component or part for a water purification apparatus as defined in any one of claims 1 to 16, wherein the component or part comprises one or more of the following: pumps, meters, oxidisers, de-ionisers, outlets, valves, pipes, piping, drains, tanks controllers, control units, control mechanisms, taps, reservoirs, recirculation loops, filters and membranes; having one or more LED UV units therewith, preferably integrally therewith. 8. A method of cleaning a water purification apparatus as defined in any one of claims 1 to 16 and comprising one or more UV LED units located around at least one of the water pathways, one of the water outlets, or both, wherein at least one UV LED unit UV-radiates the at least one of the water pathways, a point of dispense of one of the water outlets, or both to clean same.

19. A method as claimed in claim 18 wherein the at least one UV LED unit UV-radiates intermittently or non-continuously at least one of the water pathways, a point of dispense of one of the water outlets, or both. 20. A method as claimed in claim 19 wherein the water purification apparatus includes a handset and a housing, and the method includes at least one UV LED unit being activated following variation of the location of the handset relative to the housing.