Patent Application
20150021243
The present invention relates to the field of personal water purification devices. More particularly, the invention can provide an electrolytic disinfectant generator, a solar powered charging circuit, and a filtration device.
Effective water treatment generally comprises two processes, filtration and disinfection. The United States Environmental Protection Agency and the regulatory agencies of many countries require that drinking water meet limits for clarity, typically measured by the cloudiness of the water and measured as Nephelometric Turbidity Units (NTU), and also that the water have an active disinfectant all the way to the drinking water tap. The active disinfectant standard since disinfection began in 1908 is chlorine. Many programs and devices have been employed to treat water at the municipal level, as well as at the individual level. There are currently 1.2 billion people on the planet who do not have access to safe drinking water, and many of these people are at the bottom of the economic pyramid (BOP). Many treatment strategies have been attempted at the BOP, but they all suffer from the inability to be sustainable. They all require a consumable component that requires periodic replenishment by the user. Users at the BOP typically do not have the economic resources to continue the treatment protocol due to the on-going cost and logistics to support the treatment protocol.
There is a need to provide improved and low cost point-of-use (POU) and point-of-entry (POE) water treatment systems that filter the water and disinfect the water, and that are completely sustainable and do not require an on-going cost to operate.
According to the World Health Organization, more than 5,000 children in the world die every day from water-borne diseases. More than 1.2 billion people do not have access to safe drinking water. Many grass roots level campaigns have been conducted by agencies such as the World Health Organization, the Pan American Health Organization, the Center for Disease Control and Prevention (CDC), UNICEF, US AID, many non-governmental organizations (NGOs), private non-profit organizations, and private industries to try and solve this problem. Most of the current schemes involve some form of treatment technology that includes a consumable component. These solutions include distribution of bleach such as the Safe Water Program by the CDC, filtration systems by various organizations, distribution of sachets that contain flocculant aids and disinfectants (aka Pur® sachets), devices that utilize ultraviolet (UV) light as a disinfectant (which do not maintain a disinfectant residual), and various other schemes. One thing they all have in common is that they require a consumable component, and a logistics train to support continued use of the product. They typically require some continued recurring cost to the end user—end users who often cannot afford even the basic fundamentals in life. The present invention preferably does not require a significant consumable for continued use and instead uses common salt, which is considered universally available, and has a shelf life of 10 years or greater. Once a device according to the present invention is distributed, continued use of the device does not require a new logistics train or consumables (other than common salt) and would be highly sustainable at the BOP.
The MSR/MIOX Purifier has been commercialized since approximately 2003. This device is patented under U.S. Pat. No. 6,261,464 to Herrington, et al., entitled Portable Water Disinfection System. This device uses non-rechargeable batteries to electrolyzes salt water brine solution to convert the chloride to chlorine in an electrolysis process. While this device has had significant commercial sales, user feedback indicates that this device suffers from several shortcomings in the commercial marketplace, including: 1) battery replacement requirement, 2) chlorine taste, 3) wait time, 4) lack of particulate removal, 5) complexity of instructions, and 6) high price point.
Example embodiments of the present invention can address all of these shortcomings with new innovations, configurations, and operating parameters.
In an example embodiment, the device comprises an electrolytic cell with a circuit for measuring and controlling the amount of oxidant produced in order to ensure the proper disinfectant dose to the water being treated. The device can be configured to treat different volumes based on the water container volume the end user is using. In an example embodiment, the primary electrical power source is a rechargeable battery that utilizes a solar panel as one means of recharging the battery. Additionally or alternatively, the battery can be recharged from an external power source via a USB port, as an example. In an example embodiment, the on-board rechargeable batteries can also be utilized to power other external devices such as a cell phone, GPS system, a flashlight, or other rechargeable devices. In an example embodiment, the on-board solar panel can be utilized to also re-charge other external devices such as cell phones or GPS devices, as an example.
In an example embodiment of the device, a cell phone or personal digital assistant (PDA) or computer can utilize a downloadable application to utilize either a tethered cable between the devices, or a wireless communication link (e.g., Bluetooth) between the devices to select the appropriate settings on the electrolytic device and activate the electrolytic device, as well as transmit pertinent operating parameters to the cell phone, PDA, or computer to display operating parameters of the electrolytic device such as battery life, electrolyte conductivity, or charging state, among others.
In an example embodiment of the present invention, the device incorporates a novel compact brine generator that utilizes a salt compartment that fits side to side with an electrolysis compartment. The salt compartment holds common sodium chloride salt that can be stored in sufficient quantity to treat many liters of water before the compartment has to be refilled with salt. To generate brine, the electrolysis cell is filled with water then sealed, for example by fitting a cap on top of the electrolysis cell. A water dam is located between the electrolysis cell and the salt compartment so that water placed in the electrolysis cell does not readily enter the salt compartment. As the device is rotated, for example about 90 degrees, the water from the electrolysis compartment flows over the dam to the salt compartment. The user can then shake the device to make salt water brine in the salt compartment. The device is then rotated, e.g. about 90 degrees in the opposite direction, to allow the salt water brine to flow over the dam and in to the electrolysis chamber. The circuit is then activated to convert the brine solution to the appropriate amount of chlorine based oxidant solution via electricity flowing through the controlling circuitry.
Many software applications have been developed for personal digital assistants (PDAs), or cell phones. Applications include GPS-based driving directions, music selections, measuring devices, and thousands of other applications. Applications such as the “Lake Finder” app have been developed by the Department of Natural Resources in Minnesota to help people find recreational lakes. The “Water Water Everywhere” app has been developed in England to help people find tap water sources in London in order to avoid the consumption of bottle water. In an example embodiment of the present invention, a water treatment device can incorporate display, such as a touch screen display, for using a “Water Finder” software application such as those mentioned above. To support the “Water Finder” application, the treatment device can also incorporate a global positioning system (GPS) sensor to identify the location of the user, as well as the location of all water sources on the planet. The application can show the user information such as the location of water sources in the vicinity of the user, the distance to each water source, the type of water at that source, the probability of water at that location based on meterological data, the quality of the water based on historical or seasonal data, and other data that would assist the user to find and treat the water to drinking water standards with the treatment device. A database in the “water finder” application can be developed and updated by users of the system to indicate previous successful treatment scenarios for each of the water sources.
In an example embodiment of the device, the personal purifier can also comprise a compact or folding filtration mechanism that is integral to the device, or additionally or alternately can be removed from the device when being used. Origami (the art of folding paper into complex shapes) techniques can be utilized to develop a folding filter that is in the shape of a cone or cup, but can be folded flat for storage in the device. There are a variety of filter materials that can be suitable, as an example a filter material that adsorbs all of the microorganisms in the raw water, and also destroys all of the microorganism on contact with the filter media, can be suitable. The disinfection characteristics of the filter can also ensure that biofilm does not accumulate on the filter media during storage.
Note that the following discussion refers to a number of publications and references. Discussion of such publications herein is given for more complete background of the scientific principles and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
Electrolytic technology utilizing dimensionally stable anodes (DSA) has been used for years for the production of chlorine and other mixed-oxidant solutions. Dimensionally stable anodes are described in U.S. Pat. No. 3,234,110 to Beer, entitled “Electrode and Method of Making Same,” whereby a noble metal coating is applied over a titanium substrate.
An example of an electrolytic cell with membranes is described in U.S. Patent RE 32,077 to deNora, et al., entitled “Electrode Cell with Membrane and Method for Making Same,” whereby a circular dimensionally stable anode is utilized with a membrane wrapped around the anode, and a cathode concentrically located around the anode/membrane assembly.
An electrolytic cell with dimensionally stable anodes without membranes is described in U.S. Pat. No. 4,761,208 to Gram, et al., entitled “Electrolytic Method and Cell for Sterilizing Water.”
Various commercial electrolytic cells that have been used routinely for oxidant production can utilize a flow-through configuration, pressurized or not, that is adequate to create flow through the electrolytic device. Examples of cells of this configuration are described in U.S. Pat. No. 6,309,523 to Prasnikar, et al., entitled “Electrode and Electrolytic Cell Containing Same,” and U.S. Pat. No. 5,385,711 to Baker, et al., entitled “Electrolytic Cell for Generating Sterilization Solutions Having Increased Ozone Content,” and many other membrane-type cells.
In other configurations, the oxidant is produced in an open-type cell or drawn into the cell with a syringe or pump-type device, such as described in U.S. Pat. No. 6,524,475 to Herrington, et al., entitled “Portable Water Disinfection System.” This device utilizes batteries and an internal circuit to measure electrical current being delivered to the electrolytic cell. Various electronic components and software in the electrical circuit alarm for low salt and low battery condition, and ensure that adequate power is provided to the electrolytic cell to ensure that the oxidant generated by the device has maximum disinfection efficacy.
U.S. Pat. No. 6,736,966 to Herrington, et al., entitled “Portable Water Disinfection System”, which is incorporated herein by reference, describes disinfection devices that utilize, in one instance, a cell chamber whereby hydrogen gas is generated during electrolysis of an electrolyte, and provides the driving force to expel oxidant from the cell chamber through restrictive check valve type devices. In this configuration, unconverted electrolyte is also expelled from the body of the cell as hydrogen gas is generated. In an alternate configuration in the same application, hydrogen gas pressure is contained in a cell chamber during electrolysis, but the pressure within the cell chamber is limited by the action of a spring loaded piston that continues to increase the volume of the cell chamber as gas volume increases. Ultimately, a valve mechanism opens, and the spring-loaded piston fills the complete volume of the cell chamber forcing the oxidant out of the cell chamber.
In electrolytic cells utilizing titanium substrates with noble metal coatings as the anode, the pH at the surface of the anode is typically low, on the order of approximately 3. With sufficiently high brine concentration in the electrolyte, and sufficiently low voltage potential at the anode surface, oxygen generated at the anode surface reacts to form hypochlorous acid and other chlor-oxygen compounds with no oxygen gas liberated. Typical cathodes in these electrolytic cells can be composed of titanium, noble metal coated titanium, catalyst coated titanium, nickel based allows such as Hastalloy, stainless steel, and other conductive materials impervious to high pH conditions. As the cathode, hydrogen is liberated at the cathode surface with a localized high pH value at the cathode surface. During electrolysis, the metal comprising the cathode is not oxidized or otherwise damaged during electrolysis despite the production of hydrogen at the cathode surface. Over time, titanium hydride can form at the surface of a bare titanium cathode which can cause stress concentrations in the cathode surface. To preclude this hydride formation, noble metal or catalyst coatings can be applied to the cathode surface to prevent titanium hydride from forming on the cathode surface when the cathode substrate comprises titanium.
Alternately, anode and cathode electrodes can comprise boron doped nanocrystalline or ultra nanocrystalline diamond electrodes. U.S. Pat. No. 7,144,753 to Swain, et al, entitled Boron Doped Nanocrystalline Diamond describes electrodes for electrolysis. In an alternative embodiment, electrodes can be constructed of boron doped ultra nanocrystalline diamond. One advantage of diamond electrodes is the capability to carry much higher current densities than conventional dimensionally stable anodes (DSA) which facilitates smaller and lower cost anodes for the same chlorine production capacity as DSA anodes. Diamond electrodes are also able to sustain reverse polarity which is useful in decontaminating the electrodes.
An electrolytic disinfection device can utilize sodium chloride as a salt that is converted to brine and is electrolyzed to form sodium hypochlorite or chlorine based mixed oxidants as the disinfectant. Alternately, the device can use some other form of halogen to produce a disinfectant such as sodium hypochlorite, chlorine dioxide, bromine, or other such disinfectant that can be used for disinfection. In an example embodiment, the natural chlorides that are in most waters can be utilized to make chlorine for introduction to the water to be treated. The circuit to power the electrolytic cell can comprise a rechargeable battery and an electric circuit to measure power entering the electrolytic cell chamber and thereby converting chloride and water in the electrolyte to chlorine and oxygen based oxidant components. Said electrical circuit also can integrate over-voltage, under-voltage, over-current, and/or under-current protection circuits to ensure the device is not damaged during charging or discharging of electrical power. Said circuit also can ensure that electrical conditions at the electrolytic cell are adequate to produce oxidant that is effective for the purpose of disinfection.
A rechargeable battery can be recharged using a solar panel. Alternately, the energy storage device can be a super capacitor. The device can also optionally incorporate other devices such as light emitting diodes (LEDs) or light bulbs for light generation (to monitor operation in a dark setting) or signaling, electrical terminals for providing an electrical potential to heat a resistance circuit to generate heat or flame, a global positioning system (GPS) location identification device, an electronic compass, a radio device, an emergency beacon transponder, a cell phone, a digital clock, a camera, a voice or music recorder, a data storage device, or other such electronic components. The device can also be configured to utilize the on-board solar panel or the integral storage devices (battery or supercapacitors, as examples) to charge external devices such as cell phones, PDAs, or other devices that have rechargeable batteries. Control features can also include a tethered or wireless connection to a PDA with a downloadable application that can operate and monitor the features of the disinfection device.
In an example embodiment of the current system, the device is sealed to prevent water intrusion to the inside of the device, and can include waterproofing of any external electrical connections to prevent damage from contact with water. The device can also incorporate a soft exterior band to protect the device from damage due to a drop to a solid surface such as concrete.
In an example embodiment of the present invention, for treating highly contaminated surface water or high turbidity source waters, the system comprises an on-board, or separable, filter to provide pre-filtration of the water to be disinfected. In an example embodiment, the filtration material can comprise a porous sheet to provide physical filtration of suspended particles or microorganisms. Additionally, the filter material can be prepared by incorporating a biocidal material or coating to minimize contamination of the filtration media.
In an example embodiment of the present invention, for treating highly contaminated surface water or high turbidity source waters, the system comprises an on-board (or separable) filter to provide pre-filtration of the water to be disinfected. U.S. Pat. No. 7,901,660 to Xie, et al, entitled Quaternary oxides and catalysts containing quaternary oxides', describes nitrogen doped titanium oxide nano-particles that are effective as disinfectants by producing hydroxyl radicals photochemically when exposed to a light source (including sunlight). By applying these materials to the appropriate substrate filter material, the filter material physically absorbs microorganisms in the filter material and the hydroxyl radicals generated by the doped titanium oxide material proceed to inactivate all of the microorganisms that have been captured by the fabric material. This is achieved without significant pressure loss by simply pouring water through the filter material.
In an example embodiment of the present invention, for treating highly contaminated surface water or high turbidity source waters, the system comprises an on-board, or separable, filter to provide pre-filtration of the water to be disinfected. A paper published Linnea Ista, et al, published in the American Chemical Society journal Applied Materials and Interfaces entitled “Conjugated-Polyelectrolyte-Grafted Cotton Fibers Act as ‘Micro Flypaper’ for the Removal and Destruction of Bacteria”, describes conjugated polyelectrolytes (CPE) that are bonded to a fabric substrate which becomes effective as disinfectant by producing singlet oxygen when exposed to visible light. By applying the CPE to the appropriate substrate filter material, the filter material adsorbs the microorganisms and the light induced singlet oxygen proceeds to inactivate all of the microorganisms that have been captured by the fabric material. This is achieved without significant pressure loss in the filter material.
In order to provide compact storage, yet a useful shape (i.e. cup-shape) for filtering source water, an example embodiment of this invention incorporates origami folding techniques to design an appropriate filter that can be repeatedly folded and unfolded for use or storage in a compact configuration.
Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or can be learned by practice of the invention. The objects and advantages of the invention can be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The accompanying drawings, which are incorporated into and form a part of the specification, illustrate example embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating a preferred embodiment of the invention and are not to be construed as limiting the invention. In the drawings:
The present invention provides a solar power recharged electrolytic device, optionally powered by an energy storage device such as a rechargeable battery or supercapacitor, which can be used to produce disinfectant solution to make water safe to drink. Embodiments of the present invention can further comprise a recharging port, such as a USB port, in addition to the on-board solar panel. Said recharging port can recharge the internal battery in the device from an external power source, and can additionally or alternately be used as a connection port to utilize the internal battery to charge other external devices such as cell phones, GPS receivers, flashlights, or other devices that have rechargeable energy storage capabilities. Common, and low cost, rechargeable batteries typically come in two voltage configurations, 3.7 volts and 1.5 volts DC. USB chargers provide a power source of 5 VDC. A battery must be recharged with a voltage source that is greater than the nominal battery voltage. That is why a typical cell phone charger produces 5 VDC to recharge cell phone batteries, most of which have been standardized at a nominal voltage of 3.7 volts DC. Also, the nominal voltage to produce effective disinfectant needs to be supplied to the electrodes at a voltage of greater than that supplied by a single 3.7 VDC battery. Accordingly, two 3.7 VDC cell phone batteries can be used in series to produce the necessary voltage for the electrolysis process which would then be conditioned by the circuit to send the correct voltage to the electrolytic cell. In an example embodiment of the present invention, four 1.5 VDC rechargeable batteries can be utilized in series to produce 6 VDC which is sufficient voltage to provide power to the electrolysis process, and also sufficient power to recharge batteries in external devices after conditioning by the circuit. In order to recharge the internal batteries in the disinfection device, they can be recharged in a parallel circuit from an external charger providing approximately 5 VDC, or from an on-board solar panel that can be configured to supply approximately 5 VDC. Circuitry on the printed circuit board (PCB) in the device can be utilized to connect the internal batteries in a series configuration during electrolysis or during the time that the internal batteries will be utilized to charge external devices.
Production of disinfectant solutions via electrolysis is well documented in the literature. In the simplest embodiment, the process utilizes an anode electrode and a cathode electrode with a brine solution between the electrodes. Electrical energy is applied to the anode and cathode and transmitted to the brine solution, converting the brine solution to a disinfectant. In a typical electrolysis process, sodium chloride (salt) is added to water in an electrolytic cell chamber. The amount of disinfectant produced is typically a direct function of the amount of energy applied to the brine solution, and is typically independent of the concentration and volume of the brine solution. This feature is fortuitous from an operational standpoint because the operator does not need to closely control how much water is added to the electrolytic cell chamber, nor how much salt is added.
After electrolysis of the salt water solution, the disinfectant produced in the process is added to a container of water to disinfect the water. Unconverted salt in the disinfectant solution is simply added to the water to be treated, thereby increasing the total dissolved solids (TDS) concentration in the treated water. Typically, the amount of unconverted salt added to the treated water is well below the taste threshold. An important aspect of the electrolysis process is control of the voltage and total current applied to the brine solution from the power source, as this effects the quality and strength of the oxidant generated. Fortunately, these characteristics can be controlled by an electrical circuit in the disinfectant device. The electrical circuit can comprise a microcircuit and/or a microcontroller that can be small and low cost.
The electrical circuit is can be capable of conditioning the applied voltage such that the rechargeable battery is properly recharged. The electrical circuit can also cease charging the rechargeable battery when it has become fully charged. Many batteries today are already supplied with this circuitry on-board. Whether the circuitry is supplied with the battery or on the circuit board can be determined as a matter of economics. A full recharge can be indicated by a light emitting diode (LED) or other signaling device. One or more LEDs can also be utilized to provide various indication functions for the device. For example, LEDs can be utilized to indicate salinity that is too low or too high, that the battery voltage is too low to run the cell, or to indicate completion of the electrolysis cycle.
In the operational mode, the electrical circuit can ensure that the proper electrical conditions exist for the electrolysis process. During electrolysis, the voltage applied to the anode and cathode electrodes can be maintained constant throughout the entire process to facilitate production of the proper strength oxidant. Low strength oxidant can result in less than optimum disinfection performance. The electrical circuit can monitor and measure the appropriate voltage and amperage, and can provide an alarm to the user if performance is not within a specified range. Similarly, if low amperage draw is detected due to low brine concentration in the electrolytic cell, the circuit can provide an indication of a low salt condition (e.g., if the user did not add enough salt to the electrolytic cell).
In the example embodiment of the present invention shown in
After the energy in the rechargeable battery is partially or fully depleted, energy can be restored to the rechargeable battery(ies) (or other energy storage device) from solar panel 40 via the electrical circuit. In an example embodiment of the present invention, the battery(ies) can also be recharged from external power sources via USB inlet port 34. The presence of power feeding the onboard battery(ies) is indicated by illumination of charge indicator LED 36. Charge indicator LED 36 can indicate continuous charge whether the onboard battery(ies) are being charged from solar panel 40 or from an external source via USB inlet port 34. In an example embodiment of the present invention, USB outlet port 38 can be utilized to deliver power from onboard solar panel 40 to other external rechargeable devices such as cell phones, GPS devices, flashlights, etc. This can be especially valuable to users in the military on reconnaissance or for disaster relief personnel, or for individuals who might find themselves lost in the outdoors. This feature is not suggested in the prior art related to hand held water purification devices. To further provide utility for disinfection device 20, the complete assembly can be hermetically sealed so that disinfection device 20 can be immersed under water or exposed to other harsh environments without damaging the device. Sealed disinfection device 20 can be buoyant to avoid loss of disinfection device 20 in a body of water. To ensure water tight sealing of disinfection device 20, USB inlet port 34 as well as USB outlet port 38 can also incorporate elastomer covers. In an alternative embodiment of the current invention, light emitting diode (LED) 32 can be activated by LED activation switch 30. This feature allows the operator to operate the device in the dark, or to use disinfection device 20 as a flashlight. For military applications, LED 32 can be omitted, in order to avoid exposing the operator to hostile action, or made in a red light configuration, to preserve night vision of the user.
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For users at the bottom of the economic pyramid (BOP), local economics and philanthropic organizations demand that the electrolytic disinfection device be as low cost as possible. To be viable at the bottom of the economic pyramid the device must also be sustainable, a feature that no other electrolytic purifier device on the market can claim. In that sense, there must be no consumables such as replacement batteries. In an example embodiment of the current invention shown in
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The present invention can also incorporate other devices or electronic components, including but not limited to a compass, a position finding device, a location beacon transmitter, a cell phone, a camera, a clock, a timer, and/or a reflection mirror. The device can also incorporate a Bluetooth circuit to link to a cell phone, personal digital assistant (PDA) or other device that can include a software application (app) to indicate the charge condition of the solar purifier or other data such as the GPS and water location functions described above.
In an example embodiment of the present invention shown in
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As an alternative to utilizing brine bottle 256, the correct concentration of salt can be produced in cell chamber 260 by utilizing a salt applicator. The salt applicator is used to add a predetermined amount of halogen salt to water in the cell chamber 260, thereby creating brine in situ. In one example embodiment, the salt applicator can be comprised of a rod or brush that would first be wetted with water, and then placed in salt storage container 278, allowing salt to stick to the water that is adhered to the applicator. In another embodiment, the salt applicator would comprise a handle and scoop or other measuring device. In yet another embodiment, the salt applicator would comprise a handle and a porous matrix that is pre-impregnated with a halogen salt (e.g. sodium chloride.) The salt applicator would be designed to hold the correct amount of salt that is needed for one charge of brine for cell chamber 260. After cell chamber 260 is filled with water, the salt applicator would be stirred in cell chamber 260 until all of the salt is dissolved.
Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US12/23063 | 1/30/2012 | WO | 00 | 7/19/2014 |
