WO1997006108A1

WO1997006108A1 - Portable water sterilizer

Info

Publication number: WO1997006108A1
Application number: PCT/CA1996/000529
Authority: WO
Inventors: Walter Edmond Petrowich
Original assignee: International Water-Guard Industries Inc.
Priority date: 1995-08-04
Filing date: 1996-08-02
Publication date: 1997-02-20
Also published as: AU6652296A; CA2201706A1

Abstract

A portable water purifier comprises a housing including a waterproof container and a power supply. The container includes an upper chamber with a water entry porthole, a water exit porthole and a replaceable filter. A lower chamber includes a UV source and an enclosure for the electrical components. The filter cartridge, when in place, partitions the upper chamber from the lower chamber and separates a pre-sterilization area in the upper chamber from a post-sterilization area.

Description

PORTABLE WATER STERILIZER

FIELD OF THE INVENTION

The present invention relates to portable water purifiers and sterilizers and, in particular, to devices capable of portable ultra-violet sterilization. BACKGROUND OF THE INVENTION

Obtaining pure drinking water in many foreign countries is difficult, if npt impossible, from the local water supply. Travellers, therefore, are often plagued with various sicknesses caused by microorganisms and pathogens, such as coliform bacteria, endemic to those countries and against which they have no immunity. In addition to travellers, those partaking in rural activities such as camping, hiking and backpacking require a clean, safe water supply. The bacteriological content of water supplies in rural areas may be very high due to the local animal population.

Sterilizing tablets are known but their efficacy is questionable and they often impart an unpleasant taste to the water. It is known that ultra-violet("uv") radiation can be used to kill organic contamination within water supplies and it is on this basis that a number of sterilizing devices have been developed.

US Patent No. 4755292 to Merriam describes a battery powered uv sterilizer having a water reservoir in a bottom housing and a top housing or lid encasing a uv lamp and the batteries. This device is simple, but there is no means by which particulate matter or inorganic contaminants may be removed.

US Patent No. 4762613 to Snowball discloses a portable sterilizer with a uv lamp forming the core of a first chamber which is connected to a water reservoir chamber. The water passes by the uv lamp as it is being poured. There are numerous difficulties with this device. Firstly, there is a significant risk of re-contamination of the sterilized water as it may How back through the horizontal passage connecting the two chambers. Secondly, this design does not seem to afford an appropriate uv exposure time for the water to ensure pathogen destruction.

US Patent No. 4849 100 to Papandrea describes a briefcase style sterilization unit comprising, in series, a plurality of filters and a uv chamber. The briefcase itself is the main chamber into which the water to be sterilized is poured. The water is then pumped from chamber to chamber via a series of conduits or delivery lines. The main problem with this type of arrangement is contamination as water remaining in these conduits during periods of non-use may contain bacteria, which will grow and then recontaminatethe subsequent water cycle. The only solution to this problem is chemical disinfection of the unit prior to each use which is time consuming, inconvenient and costly.

US Patent No. 5 106495 to Hughes discloses a solar-powered system using uv light as an ozone generator. The device comprises, among other components, a venturi means, an ozonation means including the uv source and a circulation pump. As with the patent to Papandrea described above, this product is at risk of contamination due to the nature of the pumping and circulation system.

US Patent No. 4 151 085 to Malik describes a device, the crux of which appears to be a control mechanism to regulate water flow through the purification system.

None of these devices provides a simple, effective and reliable uv sterilization unit which is truly portable and which is not at constant risk of recontamination.

It is an object of the present invention to obviate or mitigate the above disadvantages.

SUMMARY OF THE INVENTION The present invention provides a portable water purifier which comprises a housing including a waterproof container and a power supply, said container comprising an upper chamber having a water entry portal, a water exit portal and a replaceable filter cartridge and a lower chamber in which is disposed a uv source and an enclosure for the electrical components. The filter cartridge, when in place, selectively partitions the upper chamber from the lower chamber and separates, in the upper chamber, a pre-sterilization area adjacent the entry portal from a post-sterilization area adjacent the exit portal.

Water is thereby passable via the entry portal to the pre-sterilization area and through a first part of the filter cartridge to the lower chamber where it is exposed to uv radiation for a pre¬ determined length of time, and then, on disposing the container to the pouring position, the water is removed by passage through a second part of the filter cartridge and finally through the exit portal.

The present invention also provides various types of replaceable filter cartridges for use in the purifier as described herein. The filter cartridge, in a most desirable form, comprises a base plate on which is disposed a first, entry filter, a second, exit filter and a partition to separate the first filter from the second filter.

The water purifier of the present invention is compact and effective and may be used under any conditions in which pure, clear water is required. Pumps and conduits, which are breeding grounds for bacteria, are not necessary. Without limiting the generality of the foregoing, the purifier may be readily carried by travellers, both business and pleasure, to locales in which the water supply is suspect. It may also be used by campers, hikers or backpackers in areas of potentially high coliform counts. In addition, the purifier is ideal for rural worksites such as mines, logging camps and construction areas. Lastly, it is contemplated that the purifier may be of particular use as part of emergency preparedness programs for earthquakes, fires, tornadoes, hurricanes, etc., in both consumer and corporate contexts.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a water purifier and sterilizer with the housing in the closed position;

Figure 2 is a perspective view of a water purifier and sterilizer with the housing in the open position to show its contents;

Figure 3 is an exploded perspective view of the container component of a water purifier and sterilizer showing an upper chamber, a filter cartridge, a lower chamber, a uv lamp and some electrical components;

Figure 4 is a cross sectional view of a container; and

Figure 5 is a perspective view of a filter cartridge.

PREFERRED EMBODIMENTS OF THE INVENTION Referring to Figure 1 , there is provided generally at 10 a water purification and sterilization unit. Housing 12 is depicted in a closed position suitable for transportation, with handle 14 disposed at the top of the housing.

Figure 2 depicts unit 10 with housing 12 opened about a hinge (not shown) to expose a removable container 16, a power supply 18 and a container securing means 20. This securing means includes any type of arrangement which reasonably holds the container within the housing when not in use. Preferably, the securing means may be a belt, strap, mesh or fabric cover arrangement or it may comprise a set of retractable arms. Most preferable, the securing means comprises a set of fabric or plastic straps connectable by velcro strips. It is to be understood, however, that depending on the shape of the housing, a securing means may not be necessary. Figure 2 depicts container 16 in a position "removed" from cradle 22 and thereby ready for operation as described further hereinbelow. Cradle 22 may additionally comprise an insert made of, for example, foam or rubber, to protect the container from movement of the housing during transportation. As may be seen in Figure 2, but more particularly in Figure 3, container 16 comprises upper chamber 24 which is removably connected to lower chamber 26. In a preferred form, the upper chamber forms a "lid" of container 16. Upper chamber 24 includes an entry portal 28 (shown in Figure 4) adjacent pre-sterilization zone 29 and exit portal 30 adjacent post-sterilization zone 31. A cap 32 is provided for removable sealing of exit portal 30. A hinged door or cap 33 is provided for removable sealing of entry portal 28. These caps may be either integral with the body of upper chamber 24, hinged to upper chamber 24 or they may be separate and distinct parts.

Lower chamber 26 includes water reservoir 34, uv lamp 36 and enclosure 38 for storage of the electrical components including receptacle or socket 40 through which uv lamp 36 may be connected to power supply 18. This connection is enabled by, for example, connector cable 42. UV lamp 36, which is preferably mercury, is encased within a vacuum sealed quartz sheath or other means by which contact between the water and the uv lamp is avoided.

Removable filter cartridge 44 is engagable within upper chamber 24. This filter cartridge selectively partitions upper chamber 24 from lower chamber 26 and within the upper chamber itself, defines pre-sterilization zone 29 and post-sterilization zone 31 , which zones are distinct when the filter cartridge is in place. In a preferred embodiment, upper chamber 24 comprises partition 46 which separates pre-sterilization zone 29 from post-sterilization zone 31. As shown best in Figure 5, filter cartridge 44 preferably comprises platform 48 which is divided into two filtration regions. The first filtration region is indicated at 50 and may comprise any general particulate filter which enables removal of large debris and matter such as sand, silt and sludge from the water. Most preferably, region 50 includes a sediment or turbidity screen formed of a porous fabric, mesh, cellulose or plastic. When filter cartridge 44 is in place within upper chamber 24, filtration region 50 is adjacent and below pre-sterilization zone 29.

A second filtration region is indicated at 52 and provides, when the device is in operation, a filtering system after uv sterilization. Filtration region 52 includes a compartment within post-sterilization zone 31 for different types of purification media so that a wide range of pollutants may be eliminated. Filtration region 52 may include wall 53 between pre- sterilization zone 29 and post-sterilization zone 31 abutting partition 46 of upper chamber 24. Media within filtration region 52 may be selected to target specific inorganic or organic contaminants. In a preferred form, the media within filtration region 52 may be selected from activated carbon or granular activated charcoal (GAC) for the removal of trace chemicals such as chlorine and trace organic compounds and ion exchange chelate resins or zeolite for the removal of trace metals such as lead and copper. An exhaustive list of resins is not provided herein as appropriate ones are well known and documented in the art. For example in US Patent No. 5 174879, which is incorporated herein by reference, a number of nitrate-specific anion exchange resins are disclosed. Similarly, there are many disclosures of cationic resins used in water purification.

Preferably, the activated carbon is a blend of high grade activated carbons including bituminous and coconut shell carbons. These carbons may be blended for the optimal reduction of organic chemicals, herbicides, pesticides and. industrial solvents. The average grain size of the activated carbon, in a preferred form, is between 5 to 100 meshes, more preferably between 8 to 60 meshes.

Optionally, the GAC may be silver impregnated to retard growth of bacteria within the filter. For the most part, however, this precaution will not be required as the design of the unit of the present invention ensures uv sterilization prior to exposure of the water to GAC thereby killing the bacteriological contaminants.

The exact selection of media to be incorporated within filtration region 52 depends on the context in which the unit will be used. For example, if water is to be purified in a rural area (i.e. camping, worksites, etc.) the user will primarily be concerned with the removal of bacteriological contaminants via uv sterilization. In this context, the focus may not be on the removal of trace chemicals and trace metals. Accordingly, the filter cartridge which may be chosen need not necessarily include the secondary filter components in filtration region 52. Conversely, if tap water from an industrialized urban area is to be purified, the selection of GAC and/or resins within the cartridge becomes more important. In a deluxe version of the filter cartridge, filtration region 52 is internally apportioned to contain several different types of purification media as described herein.

Filter cartridge 44 may be easily removed and replaced. It is contemplated that the user of the unit of the present invention will purchase replacement filter cartridges as required and select the cartridge for each use based on the media disposed therein. In the embodiment of the invention depicted in the figures, filtration region 52 includes an outlet orifice 54 which is functionally aligned with exit portal 30 when filter cartridge 44 is in place.

Power supply 18 comprises at least one rechargeable battery operatively connected to a battery charging array which can function at 12 V DC, 115 V AC or 220 V AC. Power supply 18 additionally comprises a printed circuit board (PCB) which provides, through a step down transformer, 12 V DC to the unit. In a preferred form, a rectifier within the transformer raises the voltage to the 115 V generally necessary for the operation of uv lamp 36 when the unit is supplied with either an AC or DC power source. Preferably, the transformer is a Class 2 transformer. The battery may be any cadmium or deep charge acid lead variety which is preferably 12 V DC. Power supply 18 is arranged either to power the uv lamp directly through an electronic circuit or to charge the battery when the unit is not in use but plugged in via electrical outlet connector 56 (shown in ghost outline in Figure 2).

The PCB is powered by the battery within power supply 18 and is designed to activate the uv lamp when switch 58 (which is preferably pressure sensitive) is depressed. The circuitry contained with power supply 18 is generally known in the art and is described only briefly herein. In a most preferred form, the activation and operation of uv lamp 36 is signalled by a light emitting diode (LED) indicator (preferably green). The PCB may additionally comprise a timer circuit which indicates the completion of one, typically 10 second cycle. The timer circuit then activates an audible alarm (by way of an amplifier circuit) or a visual alarm, preferably an LED. The circuitry may be designed to automatically turn off the uv lamp at a predetermined time after the completion of one cycle i.e. 5 to 10 seconds, to conserve battery power.

In another preferred embodiment, a series of LED indicators operatively connected to the PCB and indicatedat 60 in Figure 2, are provided on the casing of power supply 18, one of which indicates the charging level of the battery (eg: green for fully charged; yellow for 60% power; red for 50% power), another of which indicates that the battery is being recharged and another of which indicates that the uv lamp is in operation.

In operation, and with reference to Figure 4, assuming that the battery has been properly charged, the unit of the present invention may be carried in baggage, knapsacks, briefcases and the like to remote areas at which there may be no available electrical power supply, and used to purify and sterilize water. Recharging the battery prior to use is simple and convenient. Voltage is applied to power supply 18 through electrical outlet connector 56 using an AC outlet or DC source. Alternately, if an electrical power supply is available, the battery can be bypassed by connecting the power supply directly to an electrical outlet, for example in a vehicle cigarette lighter. If the electrical power supply is not 12 V DC, a suitable adapter may be required.

Container 16 is removed from cradle 22 in preparation for purification and sterilization of the water. Connector plug 42 is removed from enclosure 43 within the power supply casing and attached to both container 16 and power supply 18. Wateris poured through entry portal 28 to pre-sterilization zone 29. Gravity flow directs the water through first filtration region 50 of filter cartridge 44 for the removal of large debris and particulate matterto reservoir 34 in lower chamber 26. Within the reservoir, the water is exposed to uv radiation for a predetermined time period once the user activates the PCB through switch 58. On most occasions, a 10 second cycle of uv radiation generating a dosage of approximately 30 000 MWScm2 will be sufficient. The user may, out of an abundance of caution, repeat the cycle for an additional 10 seconds thereby generating a total dosage of 60000 MWScm2. Once the cycle(s) are completed, container 16 is disposed in a pouring position thereby allowing the water to pass through second filtration region 52 of filter cartridge 44 to post-sterilization zone 31 and finally out of the container via exit portal 30. Connector plug 42 and electrical outlet connector 56 may then be stored within enclosure 43 and container 16 returned to cradle 22.

It is suggested that after continued operation, the unit may be cleaned by passing bleach (one or two teaspoons) therethrough. Such a cleaning is not, however, required after each use.

The uv lamps which may be used in accordance with the present invention generally have a lifespan of approximately 5000 to 7000 running hours. It is recommended that the uv lamp be replaced accordingly. The design of the unit described herein allows simple and convenient removal of the uv lamp from socket 40.

In a preferred form, housing 12, container 16 and filter cartridge 44 may be made of any suitable polymer based material such as plastic. It is not essential that the housing be rigid i.e. it may be made of a soft, yet padded material not unlike a camera case.

The housing and containermay be of any reasonably portable size and dimension. In a preferred form, the reservoir in the container holds approximately 13 oz of water.

Claims

WE CLAIM:

1. A portable water purifier which comprises a housing, said housing including a removable container and a power supply, said container comprising an upper chamber having a water entry portal, a water exit portal and a replaceable filter cartridge, and a lower chamber comprising a uv source and an enclosure for electrical components, said filter cartridge, when in place, selectively partitioning the upper chamber from the lower chamber and in the upper chamber, separating a pre- sterilization area adjacent the entry portal from a post-sterilization area adjacent the exit portal, whereby, in operation, water is passable through the entry portal into the pre- sterilization area, through a first part of the filter cartridge to the lower chamber where the water is exposed to uv radiation for a pre-determined length of time, and as the container is disposed in the pouring position, the water is passable through a second part of the filter cartridge to the post-sterilization area and through the exit portal.

2. The purifier of claim 1 wherein the upper chamber is a removable lid of the container.

3. The purifier of claim 1 wherein the first part of the filter cartridge comprises a sediment screen.

4. The purifier of claim 1 wherein the second part of the filter cartridge comprises granular activated charcoal.

5. The purifier of claim 1 wherein the second part of the filter cartridge comprises a resin.

6. The purifier of claim 1 wherein the second part of the filter cartridge comprises activated carbon.

7. The purifier of claim 1 wherein the second part of the filter cartridge comprises any combination of granular activated charcoal, resin and activated carbon.

8. The purifier of claim 1 wherein the power supply comprises a battery.

9. The purifier of claim 1 wherein the power supply comprises at least one battery operatively connected to a battery charging array.

10. The purifier of claim 1 further including a timer means for intermittently operating said uv source for pre-determined time periods.

11. The purifier of claim 1 further including a timer means for intermittently operating said uv source for pre-determined time periods and an alarm means operatively connected to said timer means for indicating the end of the pre-determined time periods.

12. The purifier of claim 1 wherein the power supply comprises a battery and the housing includes a signal means to indicate the level of performance of the battery.

13. The purifier of claim 1 wherein the power supply comprises a battery and the housing includes a signal means which comprises a plurality of coloured light emitting diodes, said signal means indicating the level of performance of the battery.

14. A filter cartridge for use in a portable water purifier comprises a base platform on which is disposed a first filter, a second filter and a water-impermeable partition to separate the first filter from the second filter.

15. The filter cartridge of claim 14 wherein the first filter comprises a sediment screen.

16. The filter cartridge of claim 14 wherein the second filter comprises granular activated charcoal .

17. The filter cartridge of claim 14 wherein the second filter comprises resin.

18. The filter cartridge of claim 14 wherein the second filter cartridge comprises activated carbon.

19. The filter cartridge of claim 14 wherein the second filter cartridge comprises any combination of granular activated charcoal, resin and activated carbon.