Abstract:
A portable water purifier ( 10 ) is disclosed herein. The portable water purifier ( 10 ) includes a container ( 11 ) for containing the liquid and mates with an ultraviolet light source ( 18 ) for purifying the liquid with ultraviolet radiation.

Description:
The present invention relates generally to a water purification apparatus and, more particularly, to a portable water purifying and germicidal disinfecting system that utilizes ultraviolet radiation to prepare water for human consumption. 
     BACKGROUND OF THE INVENTION 
     Natural water supplies can be contaminated by any number of disease-carrying microorganisms, from bacteria to protozoa to viruses. Consuming water that contains these organisms can lead to cramps, vomiting, diarrhea and even more serious medical problems. For water to be safe to drink, these microorganisms must be either rendered inactive or removed. 
     There exists a need for portable water treatment systems for providing water suitable for human consumption at remote locations. This need exists, for example, in rural areas where sophisticated water treatment facilities are not present, and in the aftermath of disasters such as earthquakes and hurricanes where the local water supply has been contaminated or disrupted. While enjoying recreational activities of extended periods of time, such as hiking or camping, there is a need for water to be purified in relatively small quantities. In these instances, some effective method of treating local water supplies becomes necessary. 
     Various devices have been developed to disinfect water using irradiation of infected water with certain frequencies of electromagnetic radiation such as those in the ultra-violet range. U.S. Pat. No. 4,849,100 issued to Papandrea discloses a portable water purifier which shuts off the water flow therethrough upon sensing that the ultraviolet light intensity has fallen below a predetermined level, in an attempt to ensure that all of the water is sufficiently purified. U.S. Pat. No. 4,755,292 issued to Merriam discloses a portable ultraviolet water sterilizer with ultraviolet reflective sidewalls, in an attempt to shield the user from harmful ultraviolet radiation and cause the water to be efficiently exposed to ultraviolet light. 
     The devices used heretofore have generally proved to be unsatisfactory for one or more reasons. Most irradiation water purification devices have been designed to remain stationary, having the water flow through as it is exposed to ultraviolet light, and thus require the use of a pump. Certain apparatuses of this type become coated with materials opaque to ultraviolet light after repeated use, and thus prevents satisfactory disinfection. Other devices do not provide a sufficient duration or intensity of ultraviolet light to-fully disinfect the water. Many of the portable devices fail to provide a sufficient amount of ultraviolet light, as to do so might cause the ultraviolet bulb to overheat and become inoperable. Other devices have relied on the tendency of ultraviolet light to catalyze the formation of ozone from oxygen. However, these devices require a great deal of power to be consumed, and if portable, a bulky power source to be attached. 
     A portable water system must be compact, lightweight, and convenient to use. In addition to these requirements, a portable water purification system must be effective in purifying water to a suitable quality. It is also desirable that such a system not require the addition of chemicals and the like to be added to the water which either may lessen the quality of the treated water or require additional supplies. 
     High levels and prolonged exposure to ultraviolet light has been shown in recent years to cause various skin cancers, defects relating to human eyes, and the breakdown of human deoxyribonucleic acid. Therefore, it is desirable for the ultraviolet radiation utilized by the device to be prevented from escaping the device and effecting those who wish to benefit from the device&#39;s water purification. 
     A number of portable ultraviolet water purification devices have attempted to fulfill this need. U.S. Pat. No. 4,849,100 issued to Papandrea discloses a portable water purifier which shuts off the water flow therethrough upon sensing that the ultraviolet light intensity has fallen below a predetermined level, in an attempt to ensure that all of the water is sufficiently purified. U.S. Pat. No. 4,755,292 issued to Merriam discloses a portable ultraviolet water sterilizer with ultraviolet reflective sidewalls, in an attempt to shield the user from harmful ultraviolet radiation and cause the water to be efficiently exposed to ultraviolet light. However, these devices fall short of providing an efficient, durable, convenient, reliable portable purification device for drinking water. For example, the Merriam device is not shaped to be carried but is more of a bucket, the light source does not secure or seal to the container, the container does not seal, and there is no provision for cooling the light source. The Papandrea device requires water to flow therethrough making it poorly suited to portable use. 
     SUMMARY OF THE INVENTION 
     These problems of past devices have been overcome by the present invention, a portable water purification system. The portable water purification system of the present invention includes a container in which water is to be placed. Attached to the container is an ultraviolet light source which irradiates the water, the inside surfaces of the top and side portions of the container are coated with an ultraviolet reflective material. The entire container is made of a material opaque to ultraviolet light. A battery is provided in order to provide power to the ultraviolet light source. Additionally, a sensor is provided in order to determine when the water being purified has received an adequate dose of ultraviolet radiation. Upon this determination the operator of the purification device is notified and the ultraviolet light source of the present invention is automatically shut off. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention will be had upon reference to the following detailed description when read in conjunction with the accompanying drawings, wherein like reference characters refer to like parts throughout the several views, and in which: 
     FIG. 1 is an elevated view of a first preferred embodiment of the present invention; 
     FIG. 2 is an elevated view of a second preferred embodiment of the present invention; 
     FIG. 3 is an elevated exploded view of an alternative embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     First referring to FIG. 1, a portable liquid purification system according to the present invention is there shown. The portable liquid purification system  10  includes a container surface  12 , which generally defines the boundaries of a liquid container  11 . Water, or another liquid intended for human consumption may be poured into the container  11 . A lid  14  is then placed on the container  11  so as to seal the purification system  10  from being in liquid communication with its surroundings. 
     An ultraviolet light source  18  is removably secured to the bottom of the container surface  12  in order to provide the liquid inside the container  11  with ultraviolet radiation. The ultraviolet radiation is provided by an ultraviolet bulb of a type well known to those skilled in the art, an integral component of the ultraviolet light source  18 . The ultraviolet bulb may be a deuterium lamp, or a high-pressure gas-filled arc lamp containing argon, xenon, or mercury, as is known in the art. The ultraviolet bulb may be powered by a power supply such as a battery, AC adapter, or solar cell. The power supply  17  and the bulb  19  are shown schematically in FIG.  4 . 
     The ultraviolet bulb is contained in the ultraviolet light source  18  by a lens  22  and a source wall  20 . The lens  22  is generally transparent with respect to ultraviolet light, and may be formed from quartz, fused silica, or a high tensile plastic resistant to discoloration and degradation. Preferably the container  11  does not have a bottom wall, but instead the source  18  seals off the bottom of the container when it is inserted into the recess  24 . This provides the benefit of allowing heat from the source  18  to conduct directly to the liquid in the container, thereby cooling the source. The lack of a bottom wall also allows a user to thoroughly clean the inside of the container  11  when the source is removed, thereby removing buildup from the inner surface. As is clear to those of skill in the art, there are many ways in which the source  18  may be sealed to the bottom of the container  11 . For example, it may snap into place and seal off the bottom. When the source  18  is removed, a cover may be provided for sealing the bottom of the container  11  so that water may be sterilized and stored without tying up the source. In this way, the source  18 , may be used with multiple containers. Alternatively, the container may have a transparent-to-ultraviolet bottom wall so that the container  11  will hold a liquid when the source  18  is removed without the need for a cover. Either way, because ultraviolet radiation passes from the source, through the lens  22 , and into the container  11 , the ultraviolet radiation generated by the ultraviolet bulb is allowed to effect the liquid in the container  11 . 
     The container surface  12 , as well as the source wall  20 , are substantially opaque to ultraviolet radiation. Additionally, the device will preferably shutoff, or not turn on, if the lid  14 , also made of a material substantially opaque with respect to ultraviolet light, is not secured to the container surface  12 . These characteristics protect the user from harmful ultraviolet radiation, which has been shown, in substantial doses, to deteriorate human health. 
     In order to increase efficiency, a reflective coating  16  is provided along the inner surface of container surface  12 . The reflective coating  16  is substantially reflective with respect to ultraviolet light so as to cause the liquid in the container to absorb a maximum amount of the ultraviolet radiation emitted by the ultraviolet bulb. 
     With reference now to FIG. 2, a second purification system  10  according to the present invention is there shown. This embodiment is similar to that illustrated in FIG.  1 . However, this, embodiment additionally includes an ultraviolet sensor  26 . The ultraviolet sensor  26  determines when a sufficient amount of ultraviolet radiation has been emitted to the liquid for the liquid to be safe for consumption. Upon making such a determination, the ultraviolet sensor  26  preferably causes the ultraviolet bulb to stop emitting ultraviolet light. Additionally, or alternatively, the user is notified in some manner that the purification of the liquid has been completed. This ultraviolet sensor  26  may be a photo voltaic cell, phototube, photo multiplier tube, or silicon diode, as is well known in the art. Obviously, the sensor  26  may be used with other embodiments of the present invention. As is known to those of skill in the art, the output of an ultraviolet light source  18  may degrade over time due to aging. Also, the amount of ultraviolet reaching the liquid may drop if the transparency of the lens  22  drops or sedimentation occurs. The sensor  26  allows a user to compensate for this effect and to make sure the liquid is ready to drink. As the light source  18  ages, the sensor will take longer to trigger, thereby increasing the useful life of the source  18 . It also avoids over use of the light source  18 , preventing premature battery discharge. 
     FIG. 2 also shows that the ultraviolet light source  18 , as well as the bottom portion of the container surface  12  may be threaded so as to allow the ultraviolet light source  18  to be screwed into abutment with the container surface  12 . Obviously, the ultraviolet light source  18  may also be removed in an opposite manner. This screw together arrangement is an alternative to the snap together arrangement of FIG.  1 . The screw together arrangement works well for containers with circular cross sections, as shown, but would be unsuitable for a container with an elliptical cross section. Another preferred embodiment of the present invention has an elliptical cross section to make the container easier to wear on a user&#39;s belt. Other shapes are also possible. 
     Yet another embodiment of the present invention is illustrated in FIG.  3 . In this embodiment, the ultraviolet bulb  28  protrudes into the container  11  where the liquid is housed. The ultraviolet bulb is surrounded by a lens  22  similar to that of the first two embodiments, of an appropriate shape. 
     The configuration displayed in FIG. 3, as well as similar configurations which fall in the scope of the present invention, allow for greater heat transfer between the ultraviolet bulb  28  and the liquid housed within the container  11 . Ultraviolet bulbs of the type utilized in this invention may become very hot during operation and burn out. By providing a greater surface area of contact between the lens  22  and ultraviolet bulb  28 , and the liquid, the ultraviolet bulb, will be allowed to cool more easily, and thus avoid burning out. Additionally, the container surface  12  may be formed from a substantially thermal conductive material to indirectly allow the ultraviolet bulb  28  to be cooled more efficiently. 
     In some embodiments of the present invention, a liner  29 , as shown in FIG. 3, formed of a rigid, liquid impermeable material reflective of ultraviolet light may line the inside of the container  11 . 
     Additionally, though not shown in the figures, a mechanical filter of a type well known to those skilled in the art may be attached to the container surface where the liquid is initially poured into the container  11 . In this manner, particulate contaminants may be removed prior to irradiation by ultraviolet light. 
     Ultraviolet light can act as a catalyst in the formation of ozone from oxygen molecules, readily available in ambient air. Ozone, like ultraviolet light, is an effective water sterilizing agent, Therefore, by allowing air to come into contact with the liquid being purified by ultraviolet radiation, the sterilizing action of ozone may also be utilized. 
     Having described my invention, however, many modifications thereto will become apparent to those skilled in the art to which it pertains without deviation from the spirit of the invention as defined by the scope of the appended claims.