Abstract:
A portable water purification device comprises a portable power supply, an ultraviolet light source coupled to the portable power supply, wherein the ultraviolet light source is configured to output ultraviolet light, a container coupled to the ultraviolet light source, wherein the container is configured to hold water, and wherein the container is configured to reflect ultraviolet light, and an indicator configured to output a visual indication when the ultraviolet light source is outputting ultraviolet light.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to water purification. More specifically, embodiments of the present invention relate to a UV-LED water purification system and methods of operation. 
     The inventor of the present invention is aware of different ways to purify water making it safe for human consumption. One method includes using very small pore-sized ultra-filters that can filter out small bacteria and viruses. One drawback to this approach is that such filters are expensive to manufacture and requires frequent replacement, as the pores become clogged. Another method includes immersing Hg-based UV lamps into a bottle of water. Drawbacks to this approach include that such devices are typically relative large in size, and as such, the design of purification systems have design constraints. Other drawbacks include that such devices are often fragile; generally require higher power requirements/voltages; have limited life times; and the like. 
     Additional methods for purifying water include chlorination or other chemical-based systems. Drawbacks to such approaches include introducing potentially toxic chemicals to the water, the resulting water having a chemical taste, and the like, and that the chemicals must be accurately dosed. Other drawbacks include that chemicals are often consumable and must be constantly repurchased. Still other methods require physically large systems that are non-portable, require great power, and the like. 
     From the above, it is desired to have an ultraviolet light source for water purification without the drawbacks described above. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to water purification. More specifically, embodiments of the present invention relate to a UV-LED water purification system and methods of operation. 
     Various embodiments of the present invention include a water purification system (e.g. a “water pitcher”) that uses ultraviolet LEDs to kill bacteria, viruses, and spores in unsanitary water. More particularly, unsanitary water may include water of unknown-safety, pathogen-bearing water, or other types of liquid that if consumed by a human (or other animal) could cause illness or death. 
     In various embodiments, a system may include some or all of the following elements: a) a pre-filter to remove UV-absorbing solids; b) a tube for water to flow into a holding tank; c) a holding tank to contain the water (potentially of a UV reflecting material, such as aluminum); d) a tube for channel for pouring/removing water; e) UV LEDs for emitting and directing UV light into the water to purify it (these could be in the entry tube, the holding tank, or the exit channel); f) a power source—could be a solar cell, or a connection to an external power source (battery, AC), etc.; g) an internal battery, which could be charged and used later to power the device; h) a UV sensitive detector to confirm that UV light was illuminating and penetrating the water; i) an interlock that would detect when unpurified water was entered into the holding tank; j) indicator lights, that would indicate whether the water in the holding tank had been purified or not, or the like. 
     In some embodiments, UV-LEDs have several advantages over existing solutions, including: a) compact size of the UV light source (and/or power source); b) instant on/off (on-demand) water sanitizing; c) frequent on/off cycling capability (without an effect on lifespan); d) low voltage operation (battery powered); e) long life time; f) non-consumable. 
     According to one aspect of the invention, a portable water purification device is disclosed. One device includes a portable power supply and an ultraviolet light source coupled to the portable power supply, wherein the ultraviolet light source is configured to output ultraviolet light. An apparatus includes a container coupled to the ultraviolet light source, wherein the metal container is configured to hold water, and wherein the metal container is configured to reflect ultraviolet light, and an indicator configured to output a visual indication when the ultraviolet light source is outputting ultraviolet light. 
     According to another aspect of the invention, a portable water purification device is disclosed. One device includes a housing, and a battery disposed within the housing, wherein the battery is configured to supply electrical power. An apparatus includes an ultraviolet light source coupled to the battery and disposed within the housing, wherein the ultraviolet light source is configured to output ultraviolet light in response to the electrical power and an initiator circuit coupled to the battery and the ultraviolet light source and disposed within the housing, wherein the initiator circuit is configured to allow electrical power to be provide to the ultraviolet light source in response to an input from a user. One unit includes a UV indicator disposed within the housing, wherein the indicator is configured to provide a visual indication when the ultraviolet light is output, a container coupled to the ultraviolet light source and disposed within the housing, wherein the container is configured to hold water, and wherein the container is configured to reflect ultraviolet light, and a closable, water opening within the housing, wherein the closable, water opening is configured to allow water to be input into the metal container. 
     various additional objects, features and advantages of the present invention can be more fully appreciated with reference to the detailed description and accompanying drawings that follow 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to more fully understand the present invention, reference is made to the accompanying drawings. Understanding that these drawings are not to be considered limitations in the scope of the invention, the presently described embodiments and the presently understood best mode of the invention are described with additional detail through use of the accompanying drawings in which: 
         FIGS. 1A-B  illustrate an example of various embodiments of the present invention; and 
         FIG. 2  illustrates a functional block diagram of various embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1A-B  illustrate an example according to some embodiments of the present invention. In particular,  FIG. 1A  illustrates a possible top view and  FIG. 1B  illustrates a possible side view of a device. 
     As illustrated in  FIG. 1A , a water purification device  100  may include a liquid input and/or output door  100  that allows water or other liquid to be purified into device  100 . In other embodiments, a separate input channel or opening and a separate output channel or opening may be used. In some embodiments, an interlock mechanism may be implemented with door  100  or other water output channel. In various embodiments, the interlock mechanism may selectively inhibit water from being output from device  100  upon certain conditions, e.g. water insufficiently purified. 
     Also illustrated in  FIG. 1A  are a button/switch  120  that allows a user to initiate a liquid (e.g. water) purification process. In various embodiments, one or more status lights  130  and  140  may be provided that provide visual indication to the user of the water purification status. As an example, light  130  may indicate that power is being provided to the UV lights, i.e. the water purification process is currently being performed; light  140  may indicate whether the water has been purified; light  140  may indicate that the water has not been purified; and the like. 
       FIG. 1A  also includes an external power supply mechanism for embodiments of the present invention. As illustrated in  FIG. 1B  it is contemplated that device  100  is a battery-powered device. In some embodiments, a solar cell  150  may be provided to help charge the battery. In other embodiments, the battery may be charged via a user-wind-up crank or by other mechanical means; the battery may be charged via another battery, e.g. USB or other charging port; the battery may be charged by a plug-in wall transformer; the battery may be charged inductively; the battery may be charged via fuel cell, heat, or the like; and the like. 
     In the side-view illustrated in  FIG. 1B , a device  100  may include a filtering mechanism  160 , an electrical control portion  170 , and a holding tank  180 . In this example, holding tank includes one or more high-efficiency, low voltage UV LEDs, currently under development by the assignee of the present patent application. In some examples, a UV detector/indicator  195  may also be provided. 
     In various embodiments, filtering mechanism  160  may include a physical filtration device, for example a filter with pore size of &lt;1 micron, &lt;0.1 micron, or the like. In some embodiments, the pore size may be larger, as filtering mechanism  160  may be used to filter sediments, but not pathogens, e.g. bacteria, or the like. Additionally, in some embodiments filtering mechanism  160  may include chemical treatments, e.g. silver, or the like. In light of the present disclosure, one of ordinary skill in the art will recognize other types of filtration/treatment can be performed before the UV water purification described herein. 
     In some embodiments, filtering mechanism  160  may not be needed as device  100  receives output form a separate water filtration/purification process. Accordingly, device  100  may be used to simply purify the water with UV light. 
     In various embodiments, control portion  170  controls application of electrical power to UV LEDs  190 . Further detail will be given in conjunction with  FIG. 2 . 
     In various embodiments, holding tank  180  is a holding tank  180  that holds water for purification. In various examples, holding tank  180  may be made of a metal that reflects UV light waves, such as coated stainless steel, coated aluminum, glass with an external aluminum coating, glass with a silver coating, or the like. The inventors of the present invention believe that by using a UV reflective coating, the water stored within holding tank  180  can be subject to higher doses of UV light from the UV LED and from reflected UV light from the walls of holding tank  180 . As can be seen in  FIG. 1B , UV LEDs  190  may be placed in more than one location within holding tank  180  to help ensure the water contained therein is fully exposed to UV light. 
     In the example of  FIG. 1B , a separate UV indicator  195  may be provided on holding tank  180 . In various embodiments, UV indicator  195  may visually confirm or indicate to the user that UV purification is occurring. In this example UV indicator  195  may be electrically separate from control portion  170 . In one example, if UV LEDs burn out, or the like, and do not output UV light, although indicator  130  is lit, UV indicator  195  will not “see” UV light in holding tank  180  and will indicate so. In these examples, the user will not drink the water because UV indicator  195  is not lit, for example. In some embodiments, UV indicator  195  may include a blue-LED that is exposed to the water within holding tank  180 . When the blue-LED sees UV light, it will produce a voltage across its leads, which, may power an indicator LED, for example. 
       FIG. 2  illustrates a block diagram according to various embodiments of the present invention. In this diagram, a water purification device  200  includes a battery charger portion  210 , a battery  220 , an initiator/timer portion  230 , and UV LEDs  240 . Also illustrated are a water holding tank  250  including water  260 , and a UV detector  270 . 
     As discussed above in conjunction with  FIG. 1 , battery  220  may be charged by battery charger  210  which may be a solar cell, wind-up/crank generator, external transformer or the like. In other embodiments, battery charger  210  need not be located within device  200 . 
     In various embodiments, circuit  230  is used to receive the user press of button  120 , in  FIG. 1A , for example to initiate exposure of water  260  to UV light. In various implementations, circuit  230  may include a timer mechanism that has pre-stored therein a threshold time for purification of the maximum amount of water  260  in holding tank  250 . In some embodiments, the threshold time may be double the time actually required, to account for particulate contamination, or other sediments in water  260  in holding tank  250 . 
     In some embodiments, the threshold time may dynamically vary based upon a sensed turbidity of the water. For example, another UV sensor may be provided on the opposite side of the holding tank  250  from a UV LED  240 , to sense how much UV is getting through water  260 . If little UV light is transmitted, the UV exposure threshold time may be increased. In other embodiments, the power output of the UV LEDs  240  may also be varied to adjust the duration of the disinfectant time. For example, for clear water, UV LEDs  240  may output half as much UV light as for cloudy water. 
     As discussed above, in  FIG. 2 , by using an opaque material for holding tank  180 , the power of UV LEDs can be increased, compared to embodiments where a transparent holding tank is used. More particularly, because UV light cannot normally escape, the UV light power can be increased, and the UV light that crosses holding tank  180  does not escape, but is redirected into water  260 . Such embodiments are thus believed to enable higher power UV light and shorter water purification times. 
     Further embodiments can be envisioned to one of ordinary skill in the art after reading this disclosure. For example, in other embodiments: a pre-filter may be provided to remove UV-absorbing solids; a tube may be included to allow water to flow into a holding tank; a holding tank to contain the water may include a UV reflecting material, such as aluminum, or the like; a tube may be provided to provide a channel for pouring/removing water; UV LEDs for emitting and directing UV light into the water to purify it may be located in a water entry tube, a holding tank, an exit channel, or the like; a power source may include a solar cell, a connection to an external power source (battery, AC), or the like; an internal battery may be used, which could be charged and used later to power the device; a UV sensitive detector or indicator may provide a user with visual confirmation that UV light is or was illuminating and penetrating the water; an output interlock may be provided that would detect when unpurified water (i.e. non-disinfected water) has entered into the holding tank; indicator lights or the like may indicate whether the water in the holding tank had been purified or not; a manual crank or wind-up generator may be included to power up the UV light sources; and the like. In still other embodiments, a mechanical stirring mechanism may be used within the holding tank to circulate the liquid while being exposed to the UV light source. 
     In other embodiments, combinations or sub-combinations of the above disclosed invention can be advantageously made. The block diagrams of the architecture and flow charts are grouped for ease of understanding. However it should be understood that combinations of blocks, additions of new blocks, re-arrangement of blocks, and the like are contemplated in alternative embodiments of the present invention. 
     The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims.