Abstract:
An exemplary device and method for removing undesired substances from original water comprises a cooling circuit for cooling the original water to or below approximately Zero degrees Celsius, whereby the saturation level of the undesired substances in the original water is exceeded, thereby causing segregation of the original water into purified ice, undesired precipitated solids, and a waste liquid containing the remaining undesired substances (soluble salts). Means for removing the waste liquid from the purified ice, a heating circuit for melting the purified ice into purified water, a reservoir having an inlet for receiving the original water and an outlet for dispensing the purified water, and a first water purity monitor disposed adjacent the outlet for monitoring a first purity level of the purified water are provided.

Description:
RELATED APPLICATION 
       [0001]    This application is a Continuation of, and claims the benefit of, pending U.S. Provisional application Ser. No. 61/114,079, filed Nov. 13, 2008, and the entire teachings of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The field of the present invention includes water purification. More specifically, the field includes devices, systems, and methods for purifying salty, hard, or otherwise impure water. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention may be embodied as a device, system, or method for producing purified water from salty, hard, or otherwise impure original water through a freezing and thawing process employing a closed refrigeration circuit. The refrigeration circuit may be, but is not limited to, a heat pump refrigeration circuit such as those used in an in-home refrigerators. Such a system may operate on household electricity to best enable its use as an in-home appliance. The device and method of the exemplary embodiment disclosed herein allows alteration of the purification process according to the qualities of the original water and desired purpose for the resulting water. 
         [0004]    The invention may be embodied in a device for removing undesired substances from original water comprising a cooling circuit for cooling the original water to or below approximately Zero degrees Celsius whereby the saturation level of the undesired substances in the original water is exceeded, thereby causing segregation of the original water into purified ice, undesired precipitated solids, and a waste liquid containing the remaining undesired substances (soluble salts). 
         [0005]    The device may have means for removing the undesired precipitated solids and the waste liquid from the purified ice, a heating circuit for melting the purified ice into purified water, and a reservoir having an inlet for receiving the original water and an outlet for dispensing the purified water. 
         [0006]    The device may have a first water purity monitor disposed adjacent the outlet for monitoring a first purity level of the purified water, a controller for controlling the cooling and heating circuits according to the first purity level, and a second water purity monitor disposed adjacent the inlet for monitoring a second purity level of the original water, and a controller for controlling the cooling and heating circuits according to the second purity level. The controller may further control the cooling and heating circuits according to a comparison of the first and second purity levels. 
         [0007]    The device may further have a selector for selecting a desired value of the first purity level, wherein the controller controls the cooling and heating circuits to cause the purified water to be dispensed at the desired value. The device may have a mechanical filter in communication with the outlet to filter remaining impurities from the purified water. The device may have a diverter for selectably causing the purified water to be dispensed either directly from the outlet or through the mechanical filter. 
         [0008]    The invention may be embodied as a method for removing undesired substances from original water to produce purified water comprising the steps of;
       providing a reservoir having an inlet for receiving the original water and an outlet for dispensing the purified water;   providing a first water purity monitor disposed adjacent the outlet; cooling the original water in the reservoir to or below approximately Zero degrees Celsius whereby the saturation level of the undesired substances in the original water is exceeded, thereby causing segregation of the original water into purified ice, undesired precipitated solids, and a waste liquid containing the undesired substances;   removing the waste liquid from the purified ice; melting the purified ice into the purified water; and   monitoring a first purity level of the purified water with the first water purity monitor.       
 
         [0013]    The method may further comprise providing a controller for controlling the cooling and heating, and controlling the cooling and heating with the controller according to the first purity level. The method may further comprise providing a second water purity monitor disposed adjacent the inlet, and monitoring a second purity level of the original water with the second water purity monitor. 
         [0014]    The method may further comprise controlling the cooling and heating with the controller according to the second purity level. The method may further comprise controlling the heating and cooling with the controller according to a comparison of the first and second purity levels. The method may further comprise providing a selector for selecting a desired value of the first purity level, selecting the desired level of the first purity level with the selector, and controlling the cooling and heating with the controller to cause the purified water to be dispensed at the desired value. 
         [0015]    The method may further comprise providing a mechanical filter in communication with the outlet, and filtering remaining impurities from the purified water with the mechanical filter. The method may further comprise providing means for selectably causing the purified water to be dispensed either directly from the outlet or through the mechanical filter, and actuating the means to select between causing the purified water to be dispensed directly from the outlet or causing the purified water to be dispensed through the mechanical filter. 
         [0016]    The invention may further be embodied as a device for removing undesired substances from original water using a closed-loop refrigeration circuit and comprising a cooling portion of the closed-loop refrigeration circuit for cooling the original water to or below approximately Zero degrees Celsius whereby the saturation level of the undesired substances in the original water is exceeded, thereby causing segregation of the original water into purified ice, undesired precipitated solids, and a waste liquid containing the undesired substances. 
         [0017]    The device may have means for removing the undesired precipitated solids and the waste liquid from the purified ice, a heating portion of the closed-loop refrigeration circuit for melting the purified ice into purified water, a reservoir having an inlet for receiving the original water and an outlet for dispensing the purified water, and a first water purity monitor disposed adjacent the outlet for monitoring a first purity level of the purified water. 
         [0018]    The device may further comprise a controller for controlling the cooling and heating portions according to the first purity level. The device may further comprise a second water purity monitor disposed adjacent the inlet for monitoring a second purity level of the original water. The device may further comprise a controller for controlling the cooling and heating portions according to the second purity level. The controller may further control the cooling and heating portions according to a comparison of the first and second purity levels. 
         [0019]    The device may further comprise a selector for selecting a desired value of the first purity level, wherein the controller controls the cooling and heating portions to cause the purified water to be dispensed at the desired value. The device may further comprise a mechanical filter in communication with the outlet to filter remaining impurities from the purified water. The device may further comprise means for selectably causing the purified water to be dispensed either directly from the outlet or through the mechanical filter. 
         [0020]    The closed-loop refrigeration circuit may contain a refrigerant and the heating portion may comprise a compressor for heating the refrigerant by compression thereof to melt the purified ice, and the cooling portion may comprise an expansion coil for cooling the refrigerant by allowing the expansion thereof to cool the original water. 
       BACKGROUND  
       [0021]    There exists a continuing need to reduce the salinity of sea water, to increase the softness of hard water, or to increase the purity of impure water, for various purposes. Such purposes include, but are not limited to, the production of clean water for washing and household use, the production of potable water for cooking, the production of pure water for drinking, and the production of ultra-pure water for certain industrial and medical uses. Each of these purposes requires a resulting water of a different level of purity. 
         [0022]    The purification of water from sea water or hard water is a time-consuming and expensive task. There is a benefit to reducing the time and expense of such purification. However, the purity of the resulting water and the expense of producing it are directly proportional to the time of the purification process. Resulting water purity and expense are reduced with a reduction in the purification time. But simply reducing the time and thereby producing a resulting water of insufficient purity for the desired purpose is not acceptable. 
         [0023]    Additionally, the time and expense of purification of water from sea water, hard water, or otherwise impure water, regardless of the desired purpose, is directly proportional to the salinity, hardness, or impurity level of the original water. It simply takes more time to purify water to any desired level when it is originally saltier, harder, or more impure than when it is originally less salty, less hard, or less impure. 
         [0024]    Many devices and systems for attempting to purify salty or hard water are known, but have a variety of drawbacks and failings. As examples, U.S. Pat. Nos. 4,164,854, 3,587,240, 3,630,042, 3,367,123, 3,069,864, and 1,931,347 describe various desalinization systems and methods having no ability to allow alteration of the purification process according to the qualities of the original water or the desired purpose for the resulting water. 
         [0025]    There exists the need, and such is an object of the present invention, for a water purification system or process that allows alteration of the purification process according to the qualities of the original water, for reasons including the minimization of the time and expense to only what is needed according to the instant need. 
         [0026]    There exists the need, and such is an object of the present invention, for a water purification system or process that allows alteration of the purification process according to the desired purpose for the resulting water, for reasons including to minimization of the time and expense to only what is needed according thereto. 
         [0027]    There exists the need, and such is an object of the present invention, for a water purification system or process that allows alteration of the purification process according to the qualities of the original water and the desired purpose of the resulting water, for reasons including the minimization of the time and expense to only what is needed according thereto. 
         [0028]    There exists the need, and such is an object of the present invention, to provide a more effective and efficient home appliance capable of purifying original water such as sea water, hard water, or otherwise impure water. 
         [0029]    There exists the need, and such is an object of the present invention, to provide an effective and efficient home appliance capable of purifying original water such as sea water, hard water, or otherwise impure water that allows alteration of the purification process according to the qualities of the original water, for reasons including the minimization of the time and expense to only what is needed according thereto. 
         [0030]    There exists the need, and such is an object of the present invention, to provide an effective and efficient home appliance capable of purifying original water such as sea water, hard water, or otherwise impure water that allows alteration of the purification process according to the desired purpose for the resulting water, for reasons including to minimization of the time and expense to only what is needed according thereto. 
         [0031]    There exists the need, and such is an object of the present invention, to provide an effective and efficient home appliance capable of purifying original water such as sea water, hard water, or otherwise impure water that allows alteration of the purification process according to both the qualities of the original water and the desired purpose of the resulting water, for reasons including the minimization of the time and expense to only what is needed according thereto. 
         [0032]    There exists the need, and such is an object of the present invention, to provide a more effective and efficient method for purifying original water such as sea water, hard water, or otherwise impure water. 
         [0033]    There exists the need, and such is an object of the present invention, to provide an effective and efficient method for purifying original water such as sea water, hard water, or otherwise impure water that allows alteration of the purification process according to the qualities of the original water, for reasons including the minimization of the time and expense to only what is needed according thereto. 
         [0034]    There exists the need, and such is an object of the present invention, to provide an effective and efficient method for purifying original water such as sea water, hard water, or otherwise impure water that allows alteration of the purification process according to the desired purpose for the resulting water, for reasons including to minimization of the time and expense to only what is needed according thereto. 
         [0035]    There exists the need, and such is an object of the present invention, to provide an effective and efficient method for purifying original water such as sea water, hard water, or otherwise impure water that allows alteration of the purification process according to the qualities of the original water and the desired purpose of the resulting water, for reasons including the minimization of the time and expense to only what is needed according thereto. 
         [0036]    Further objects and advantages of the invention will become apparent in view of the following disclosure of an exemplary embodiment thereof and drawings related thereto. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]      FIG. 1  shows an apparatus according to an exemplary embodiment of the invention; 
           [0038]      FIG. 2  is a schematic diagram of the apparatus of  FIG. 1 ; 
           [0039]      FIG. 3A  is a diagram of a typical Heat Pump operating in cooling mode; 
           [0040]      FIG. 3B  is a diagram of a typical Heat Pump operating in heating mode; 
           [0041]      FIG. 4  is a graph of the conductivity of output water according to the brine conductivity during a purification cycle using the apparatus of  FIG. 1 ; 
           [0042]      FIG. 5  is a chart of process information for various purification cycles using the apparatus of  FIG. 1 ; and 
           [0043]      FIG. 6  shows a cascaded arrangement connecting components of the apparatus of  FIG. 1  in series. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0044]    A first exemplary embodiment for practicing an apparatus and method for producing potable water in accordance with the invention is now described and shown in  FIGS. 1 and 2 , where there is shown purification system  100 . 
         [0045]    The main components of system  100  are a process water holding tank  102 , a heating and cooling system  104 , and a purified water holding tank  106 . Additional components of the exemplary embodiment include a waste water holding tank  108 , a controller  110 , a micro filter  148 , and a mobile cart  112 . 
         [0046]    The process water holding tank  102  is preferably constructed of stainless steel, with a capacity of approximately 30 litres. A process water inlet  114  is disposed adjacent the top of the tank and an outlet  116  is disposed at the base of the tank. 
         [0047]    The cooling and heating system  104  is preferably a reversible heat pump similar to those used in certain home refrigerators, allowing the reversal of the refrigerant in order to switch between the cooling and heating modes. The heat pump includes a compressor/evaporator unit  118  disposed remotely from the process water holding tank  102  and in communication with a thermal transfer coil  122  disposed within the process water holding tank  102 . No dangerous flames or chemicals need be used and the heating, no fumes are created or exhausted, and cooling requires only a household electricity supply. 
         [0048]    An explanatory description of the heat pump process is provided by the Singapore National Energy Efficiency Committee and published at
       http://www.nccc.gov.sg/building/heat_pump.shtm,
 
which is excerpted below with reference to  FIGS. 3A and 3B ;
       
 
         [0050]    Heat Pumps
       Heat pumps are commonly used in temperate countries to provide premises with cooling in summer and heating in winter. It employs the concept of reversing the refrigerating cycle as detailed below.       
 
         [0052]    Working Principles of Heat Pumps
       Both heating and cooling modes of heat pumps do exactly the same thing. They “pump” the heat from one location to another. In these examples the heat in the air is moved out of or into the space.       
 
         [0054]    Cooling Mode
       A heat pump is essentially an air conditioner with a few additions, namely a reversing valve, two thermal expansion valves and two bypass valves. The reversible selection allows the unit to provide both cooling and heating.  FIG. 3A  shows a heat pump in cooling mode. The unit operates as follows:   The compressor compresses the refrigerant vapor and pumps it to the reversing valve.   The reversing valve directs the compressed vapor to flow to the outside heat exchanger (condenser) where the refrigerant is cooled and condensed to liquid.   The air blowing through the condenser coil removes heat from the refrigerant.   The liquid refrigerant bypasses the first thermal expansion valve and flows to the second thermal expansion valve at the inside heat exchanger (evaporator) where it expands into the evaporator and become vapor.   The refrigerant picks up heat energy from the air blowing across the evaporator coil and cool air comes out at the other side of the coil. The cool air is ducted to the occupied space as air-conditioned air.   The refrigerant vapor then goes back to the reversing valve to be directed to the compressor to start the refrigeration cycle all over again.       
 
         [0062]    Heating Mode;
         FIG. 3B  shows the heat pump in heating mode. The difference between the two diagrams is the reversing valve directs the compressed vapor refrigerant to the inside heat exchanger first. This makes the inside heat exchanger to act as the condenser and gives out the heat energy. The heat is transferred to the air that blows across the coil and the heated air is ducted to the occupied space. The outside heat exchanger now becomes the evaporator. The liquid refrigerant bypasses the second thermal expansion valve and flows to the first thermal expansion valve where it expands into the evaporator. It becomes vapor and absorbs heat from the outside air. When the heat from inside coil is used to increase the temperature of water in a storage tank, the heat pump acts as a hot water generator. This can be achieved by using a heat exchanger to absorb heat from the inside coil with water circulating through it or by placing the inside coil in the storage tank.       
 
         [0064]    In the instant application of heat pumping, the “occupied space” is replaced by the process water within tank  102  and the “inside heat exchanger” and associated air blower are replaced by the thermal transfer coil  122  in direct contact with the process water. 
         [0065]    Controller  110  monitors and controls functions of the system, including the operation of valves, timing, sensing process conditions, and heating/cooling in cooperation with the sensed conditions, or according to time. 
         [0066]    Tank  102  is filled with process water through inlet  114 . The process water may be one or a combination of sea water, brine, hard water, or water containing other impurities which will drop out of solution as the process water is cooled to the approximately Zero degrees Celsius. Upper conductivity sensor  126  is disposed adjacent inlet  114  and measures the conductivity of the incoming process water, thereby establishing its impurity level, and communicates the same to the controller  110 . 
         [0067]    Lower thermal sensor  128  is positioned within a lower portion of tank  102  and communicates the temperature of the process water there-at to the controller  110 . Mid-level thermal sensor  132  is positioned within a mid-level portion of tank  102  and communicates the temperature of the process water there-at to the controller  110 . Upper thermal sensor  134  is positioned within an upper portion of tank  102  and communicates the temperature of the process water there-at to the controller  110 . 
         [0068]    Lower conductivity sensor  136  is disposed within a lower portion of tank  102  approximate outlet  116  and measures the conductivity of the process water there-at, thereby establishing its impurity level, and communicates the same to the controller  110 . 
         [0069]    After filling of tank  102  with process water is complete, controller  110  causes the cooling heating and cooling system  104  to initiate cooling of the process water. As the process water temperature drops below approximately Four degrees Celsius thermal stratification will occur, causing the cooler water to rise within the tank. Stratification is recognized by mid-level thermal sensor  132 . Ice will form within the process water in the upper portion of tank  102 , mostly from the water component thereof, as the lower thermal sensor  128  detects temperatures of Zero to Four degrees Celsius. At this point, thermal sensors  128  and  134  will sense temperatures at or below approximately Zero degrees Celsius and report the same to controller  110 . The impurities within the process water will become insoluble and accumulate within a more and more concentrated solution, hereafter referred to as “brine”, in the bottom portion of tank  102 , sensed by conductivity sensor  136  and reported to controller  110 . 
         [0070]    When the conductivity at sensor  136  reaches the pre-selected value, or when a predetermined time has elapsed, controller  110  terminates the cooling process and opens outlet valve  140  and brine valve  142 , while maintaining pure water valve  144  in a closed state, to allow the undesired precipitated solids and the concentrated brine to drain directly into waste water holding tank  108 . The ice crystals and a pre-calculated volume of the concentrated brine remaining inside tank  102  are comprised of a somewhat purified water of the desired conductivity. 
         [0071]    Upon draining of the brine, the controller causes closure of valve  140  and reversal of the heating and cooling system  104  to the heating mode to melt the ice into a liquid water that is less impure than the original process water. Once the ice is fully melted, as sensed by sensor  128 , its conductivity is reported to controller  110  by sensor  136 . If the conductivity indicates that the process water has been purified to the desired level, controller  110  causes closing of valve  142  and opening of valves  140  and  144  to allow the purified water to flow through an optional 0.2 μm filter  148  for removal of impurities not already removed and into purified water holding tank  106  where it may be used as desired. 
         [0072]    The temperature sensed at sensor  128  and the conductivity sensed at sensor  136  are used by controller  110 , as adjusted by the user to regulate the heating and cooling process according to the desired output water quality. The process may be manually controlled by setting the controller to allow the user to determine values such as output water purity, reduction of purity from the input process water, or the volume of purified water desired. The amount of time required to purify input water of various conductivities and temperatures into output water of various purity levels can be predetermined and the system can be timed to operate accordingly. 
         [0073]    Alternatively, the controller can be set such that the output quality and volume of both the brine and purified water may be controlled automatically by comparison of the conductivity and/or temperature of the incoming process water to the desired purity of the purified water using the measured parameters from the sensors. Thus, the system can more efficiently operate according to the qualities of the original process water and/or desired qualities of the purified water according to its own measurements and control. 
         [0074]    All working conditions are regulated by the controller  110  according to the readings of the thermal sensors  128 ,  132 , and  134  and conductivity sensors  126  and  136 . 
         [0075]      FIG. 4  is a graph depicting the conductivity (reciprocal of purity) of output water according to the brine conductivity of actual purification cycles using the apparatus. For this demonstration, the initial conductivity of the water was 1500 μs/cm. ten litres of brine with conductivities shown on the horizontal axis were removed from the tank after each purification cycle. The vertical axis shows the conductivity of the produced drinkable water. To obtain the lower conductivities of the output water and the greater conductivities of the removed brine, a greater process time is of course required. Initial conductivity of the water was 1500 μs/cm. 
         [0076]      FIG. 5  is a chart of process information for various purification cycles using the apparatus and incoming process water having a conductivity of 1500 μs/cm. 
         [0077]    As can be seen, the final purity of output water is flexible and regulated according to the needs of the use. In situations where water higher volume is needed and water quality can be sacrificed, such as for washing or toilet use, the system can automatically alter parameters accordingly so that time and energy are not wasted and water volume is not lost unnecessarily. In cases where maximum water purity is needed, such as for drinking or medical applications, the controller can be set to repeat the cooling/draw-off/heating cycle continuously until the needed purity level is reached, at the expense of water volume and energy consumption. 
         [0078]    As shown in  FIG. 6 , a second embodiment of the invention is shown in system  200  having multiple quantities of components from apparatus  100  of the first embodiment configured in a cascaded arrangement, using a common controller, to continuously purify water in a staged process. The first process water holding tank  102 A is used for a primary conductivity reduction, then sends its water to a second process water holding tank  102 B rather than a purified water holding tank for a secondary conductivity reduction, and so on to Nth process water holding tank  102 N. Some water may be drawn off at outlets  106 A through  106 N for use according to various needs. In this way a continuous supply of waters of increasing purity is always available instantly at the expense of energy consumption and system cost. 
         [0079]    It should be understood that, while  FIG. 6  shows a cascading of three stages, it is intended that any number of stages may be cascaded, with the “Nth” stage being the final stage, for instance, in a system that has three stages as specifically depicted, the Nth stage is the third stage; stage C. If the system was to have ten stages, those would be designated A through J with the Nth stage being the tenth stage; stage J. 
         [0080]    While a reduction of microbiological flora of more than ninety-five percent is realized without secondary filtration, the optional use of 0.2μ filter  148  at the final outlet of the first or second embodiments secures further water sterilization. 
         [0081]    While the disclosed embodiments are meant to demonstrate key features and functions of the invention, it should be understood that these embodiments are merely exemplary and that the invention should not be limited according thereto, but only according to the following claims including all equivalent interpretation entitled thereto.