Patent Publication Number: US-2005133431-A1

Title: In-home water treatment system

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a water filtration and ultraviolet light disinfection apparatus and method that are suitable for use as a point-of-entry or point-of-use water treatment system in the home. More particularly, the present invention relates to an improved home water treatment system and method that provides several water treatment stages for improved water quality, including particulate filtration, inorganic and organic contaminant removal, and microorganism inactivation.  
      2. Description of the Related Art  
      Point-of-entry and point-of-use water treatment arrangements for use in homes have been available for some time. Point-of use devices provide localized water treatment at a particular point within the home, such as filters that are attached to faucets. Point-of-entry devices are arranged near the home water-service entry point to provide whole-house water treatment. The point-of-entry devices in common use range from simple particulate filter elements, for filtering larger solid particles that are present in the incoming water, to filter elements that are intended to remove certain chemicals that are present in the incoming water, such as chlorine and organic contaminants. More recently, point-of-entry water treatment units have become available that incorporate ultraviolet lamps for disinfecting the water by exposing it to ultraviolet light in order to inactivate pathogens and other microorganisms that may be present in the incoming water.  
      Typically, separate filter units are available for the removal of the several forms of undesirable contaminants that may be present in water for household use. It is therefore desirable to provide in a unitary vessel a treatment system for removing particulates and chemicals, and for disinfection of microorganisms. Desirably, such a vessel is of a relatively compact size and is one that is adaptable for retrofitting into existing home water distribution systems.  
     SUMMARY OF THE INVENTION  
      Briefly stated, in accordance with one aspect of the present invention, a water treatment system is provided that includes a treatment vessel having an inlet for receiving incoming water from a water source, and having an outlet for discharging treated water. A first filter element carried within the treatment vessel is provided for removing particulates present in the incoming water. A second filter element carried within the treatment vessel is provided for removing chemical compounds present in the incoming water. And an ultraviolet light treatment element carried within the treatment vessel is provided for disinfection of microorganisms present in the incoming water. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a diagrammatic elevational view of one form of an in-home water treatment system in accordance with the present invention;  
       FIG. 2  is a longitudinal cross-sectional view of a water treatment vessel forming part of the system shown in  FIG. 1 ;  
       FIG. 3  is an enlarged, fragmentary cross-sectional view adjacent the base region of the water treatment vessel shown in  FIG. 2 ;  
       FIG. 4  is an enlarged, fragmentary cross-sectional view adjacent the top region of the water treatment vessel shown in  FIG. 2 ;  
       FIG. 5  is a cross-sectional view taken along the line  5 - 5  of  FIG. 2 ;  
       FIG. 6  is a cross-sectional view taken along the line  6 - 6  of  FIG. 2 ;  
       FIG. 7  is a side view of a two-stage filter assembly, partially broken away to show the internal structure;  
       FIG. 8  is a side view of a particulate filter pad of tubular form;  
       FIG. 9  is an end view of the filter pad of  FIG. 8 ;  
       FIG. 10  is a side view, partially broken away, of a carbon cartridge filter of tubular form;  
       FIG. 11  is an end view of the carbon cartridge filter shown in  FIG. 9 ; and  
       FIG. 12  is a top view of the water treatment vessel shown in  FIG. 1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring now to the drawings, and particularly to  FIG. 1  thereof, there is shown a schematic elevational view of a water treatment system  10  that can be utilized in a home, at a school, and in other places. The system shown and described herein is particularly suitable in applications in which the maximum water flow rate is of the order of about 12 gallons per minute, or less.  
      System  10  includes an incoming water supply conduit  12  that is connected with a treatment vessel  14  that can be carried on a stand  16 . If desired, treatment vessel  14  can also be wall-mounted, or it can be supported in other ways. Incoming water, such as is commonly supplied by a municipal water source, or is derived from a groundwater source such as a well or a spring, enters vessel  14  through supply conduit  12 , where it undergoes three treatment stages. The treated water exits from vessel  14  though outlet conduit  18  to be conveyed to the household water distribution system (not shown).  
      Supply conduit  12  includes a supply shutoff valve  20 , and it can also include a flow meter  22  for measuring the rate and amount of water flow. A pressure regulating valve  24  can be provided for controlling the pressure of the water before it enters treatment vessel  14  and the household water system. Flow meter  22  and pressure regulating valve  24  can be positioned downstream of shutoff valve  20  as shown, or one or both of them can be positioned upstream of shutoff valve  20 , if desired.  
      From supply conduit  12  the incoming water enters treatment vessel  14  at vessel inlet  26 . The incoming water flows within vessel  12  and through three successive treatment stages, after which treated water exits from vessel  12  at vessel outlet  28  to enter outlet conduit  18  and to be distributed to the various water usage points within the home.  
      Operation of treatment system  10  is controlled by an electrical control housing  30  that is connected with a standard 120-volt household outlet through a power cord  32 . A leakage current interrupter  34  can be provided in power cord  32 , or connected with an electrical outlet  36 , as a safety measure. Control housing  30  includes a display panel  38  with several suitable switches and indicators. As shown in  FIG. 1 , display panel  38  includes a system on-off switch  40 , a unit-on indicator  42 , which can be a visual indicator, such as a light-emitting diode, or the like, and a treatment element replacement indicator  44 , which can also be a visual indicator, such as light-emitting diode, or the like, to show the need for treatment element replacement. Additionally, control housing  30  can include a clock (not shown) to monitor the treatment system operating time, and a clock reset button  46  to reset the clock after the replacement of a water treatment element within treatment vessel  14 .  
      Control housing  30  also includes a power cable  48  to deliver electrical power to treatment vessel  14 , an electrical conduit  50  that is connected with a solenoid-operated valve  52  in outlet conduit  18 , and pressure conduits  51 ,  53  that are connected to a differential pressure switch  55  within control housing  30 . Valve  52  can be arranged, through suitable control circuitry (not shown), to stop the flow of water from treatment vessel  14  to the household water system in the event of a treatment system malfunction, or in the event of a failure to timely replace a water treatment element that is contained within treatment vessel  14 . Differential pressure switch  55  is utilized to activate visual indicator  47  when a set point differential pressure across the treatment system is exceeded, which indicates that first filter element  84  is clogged with accumulated particulate matter, such as sediment, and requires cleaning or replacement.  
      In addition to its connection with the household water distribution system, vessel outlet  28  is adapted to communicate with a drain conduit  54  in which a manually operable drain valve  56  is provided to allow or to prevent the flow of water from treatment vessel  14  into drain conduit  54 , such as through a drain receptacle  58 .  
      Treatment vessel  14  and its interior elements and structure are shown in longitudinal cross-sectional form in  FIG. 2 . Vessel  14  is a generally tubular housing and can be of cylindrical form, as shown in the drawings. Advantageously, from cost and simplicity of manufacture standpoints, treatment vessel  14  can be an injection-molded structure that can be formed from polypropylene, ABS, polycarbonate, or other polymeric materials suitable for use in pressurized potable water systems. Treatment vessel  14  is defined by an annular vessel sidewall  60 , by a disk-like, closed vessel bottom wall  62 , and by a vessel top opening  64 . Vessel bottom wall  62  includes vessel outlet  28 , which is located at a generally axial position, relative to vessel sidewall  60 , and which communicates with an outlet plenum chamber  66  that serves as a treated water collection well. Vessel inlet  26  is spaced above vessel bottom wall  62  and communicates with an annular inlet plenum chamber  68 . Outlet plenum chamber  66  is separated from inlet plenum chamber  68  by an axially-extending annular separator wall  70  that extends upwardly from vessel bottom wall  62  to a radially-extending divider wall  72  that separates inlet plenum chamber  68  from vessel inner chamber  74 .  
      Vessel top opening  64  is closed by a top end cap  76  that can be removably connected with the upper end of vessel sidewall  60 , such as by a threaded connection, as shown in  FIG. 4 . Top end cap  76  includes several radially-extending, circumferentially-spaced projections that serve as twist-off handles, to allow convenient attachment and removal of top end cap  76  from vessel  14 , as necessary. Top end cap  76  also includes a centrally-positioned opening  80  to receive a power cable connector  82 , and a pressure relief valve  83 .  
      Positioned axially within vessel inner chamber  74  and spaced inwardly of the interior surface of vessel sidewall  60  is a first filter element  84 . Element  84  is in the form of a relatively thin wall, semi-rigid, annular filter pad for filtering sediment and other particulate matter contained in the incoming water to be treated. The radial spacing between vessel sidewall  60  and the outer surface of first filter element  84  defines an outer annular flow channel  85  and can be of the order of from about ¼ to about ½ inch, to allow axial flow of incoming water along the outer periphery of first filter element  84 , and to thereby expose incoming water to a relatively large surface area through which the incoming water can flow radially inwardly toward the center of treatment vessel  14 . The radial thickness of first filter element can be of the order of from about {fraction (1/4)} inch to about {fraction (3/4)} inch, depending upon the porosity of the material that is utilized to form that filter element and the desired cleaning frequency of the filter element. In that regard, first filter element is capable of filtering from the incoming water particulate matter having a particle size of about 5 microns or larger.  
      Second filter elements  86 ,  87  are positioned axially within first filter element  84  and can also be of annular form. Second filter elements  86 ,  87  are rigid, porous carbon block filters for removing from the incoming water that passes therethrough such chemical contaminants as chlorine, chlorinated by-products, and other inorganic and organic compounds that can adversely affect the taste and odor of the water that is to be treated. The radial thickness of each of second filter elements  86 ,  87  is greater than that of first filter element  84  to provide adequate contact time for adsorption of organic contaminants from the water, typically from about ¾/inch to about 1 inch.  
      For larger treatment vessels, such as is shown in  FIG. 2 , two axially-aligned second filter elements can be provided to facilitate removal and replacement of the second filter elements when necessary during use of the apparatus. A key-notch-type orientation arrangement  89  can be provided at the lower end of uppermost filter element  87  and at the top end of lowermost filter element  86  to ensure proper alignment of the second filter elements when they are installed within treatment vessel  14 . Additionally, a tubular-shaped open-lattice plastic connector can be inserted within the interior annular space of both second filter elements to join the two elements together using a compression seal to facilitate the insertion into and the removal from treatment vessel  14  of the joined filter elements.  
      Positioned axially within second filter elements  86 ,  87 , and spaced radially inwardly thereof to define an inner annular flow channel  88  therebetween, is a third water treatment element  90 . Treatment element  90  is in the form of an ultraviolet light treatment reactor for disinfection treatment of the water by exposure of the water to ultraviolet light in order to inactivate microorganisms that may be present within the incoming water. Treatment element  90  includes an ultraviolet lamp  92  that is axially positioned within vessel  14  and is spaced inwardly from and concentric with each of first filter element  84  and second filter elements  86 ,  87 . The ultraviolet light provided by treatment element  90  serves to inactivate pathogenic microorganisms, such as  Cryposporidium, Giardia lambila , bacteria, viruses, and the like, and it avoids the need to use hazardous disinfection chemicals that can produce undesired residual chemical compounds or possibly hazardous byproducts. Treatment element  90  is adapted to provide ultraviolet radiation at wavelengths of about 254 nanometers and can be a standard, low-pressure ultraviolet lamp, for which effective light-based disinfection of waterborne microorganisms can take place. The space between the outer surface of treatment element  90  and the inner surfaces of second filter elements  86 ,  87  defines inner annular flow channel  88 , which serves to allow water that has passed through first filter element  84  and second filter elements  86 ,  87 , and that has been filtered to remove particulates and undesirable chemical compounds, to flow coaxially along the outer surface of treatment element  90  for the final treatment step, which involves inactivation of microorganisms in the water.  
      The structure of vessel  14  and the arrangement of the several treatment elements positioned therewithin are shown in greater detail in  FIGS. 3 and 4 , which are enlarged, fragmentary, cross-sectional views of the several treatment elements, as well as the vessel structure at the bottom and at the top regions, respectively, of vessel  14 . Referring first to  FIG. 3 , the base portion of vessel  14  includes annular inlet plenum chamber  68  that is bounded by vessel bottom wall  62 , by radially-extending divider wall  72  that is spaced axially from bottom wall  62 , by axially-extending separator wall  70  that extends between bottom wall  62  and divider wall  72 , and by vessel sidewall  60 . Inlet plenum chamber  68  communicates with inlet connection  26  to receive the water to be treated, and it serves to distribute the incoming water circumferentially within the interior of vessel  14 . In that regard, a plurality of substantially axially-extending, circumferentially-spaced openings  94  are provided in divider wall  72  adjacent vessel sidewall  60  to provide communication between inlet plenum chamber  68  and outer annular flow channel  85 . The number, spacing, and size of openings  94  are selected to provide the desired flow rate and flow distribution into the treatment section of vessel  14  of the incoming water that is to be treated.  
      Divider wall  72  within vessel  14  includes an annular recess  96  in its upper surface to receive a flexible, annular sealing ring  98  against which rest the lower end surfaces of each of first filter element  84  and second filter elements  86 ,  87 . Sealing ring  98  can be made from neoprene rubber, or the like, and it serves to prevent water flow around the lower ends of the first and second filter elements so that the water is confined to flow through the respective elements rather than bypassing them.  
      Separator wall  70  within vessel  14  is so sized and positioned as to provide a desired volume for outlet plenum chamber  66 , which communicates both with outlet connection  28  and with an inner annular flow channel  100  outside third treatment element  90 . Separator wall  70  can be formed with an internal thread  102 , which is adapted to threadedly receive an end of a tubular housing  104  of cylindrical form that forms part of third treatment element  90 . Housing  104  can be made from stainless steel, or the like, and serves to define the interior surface of intermediate annular flow channel  88  and the outer surface of inner annular flow channel  100 .  
      Axially positioned within housing  104  is tubular ultraviolet lamp  92  that is surrounded by a protective tubular quartz glass sleeve  106 , which is capable of transmitting ultraviolet light with minimal absorbance. Sleeve  106  has an outer diameter that is smaller than the inner diameter of housing  104  to define therebetween inner annular flow channel  100 , through which the water to be treated flows in an axial direction toward outlet plenum  66 . The lowermost end of sleeve  106  carries an annular centralizer ring  108 , which extends between housing  104  and sleeve  106  to position lamp  92  centrally within housing  104 . Centralizer ring  108  need not be fixed to housing  104 , but can be so sized as to provide a snug fit therewith, to allow centralizer ring  108  to slide along the inner surface of housing  104  to facilitate removal of treatment element  90 . Centralizer ring  108  includes a plurality of axially-extending openings  110  to allow water to flow from within inner annular flow channel  100  into outlet plenum  66 . The number, spacing, and size of openings  110  are selected to control the flow rate and the flow distribution of the water within inner annular flow channel  100  into outlet plenum  66 , to achieve a desired exposure time of the water to ultraviolet light.  
       FIG. 4  shows in cross section the upper interior portion of vessel  14 . The upper ends of each of first filter element  84  and second filter elements  86 ,  87  are retained against a flat, annular sealing ring  114  similar to sealing ring  98 . Sealing ring  114 , which can be made from neoprene rubber, or the like, is received in a correspondingly-shaped annular recess  116  formed in the lower surface of top end cap  76 . Sealing ring  114  serves to prevent water flow around the upper ends of first filter element  84  and second filter elements  86 ,  87 , so that the water to be treated is confined to flow from outer flow channel  85  into and through each of the first and second filter elements to intermediate flow channel  88 , rather than bypassing the filter elements. Positioned radially inwardly of ring  114 , and coaxial therewith, is an inner sealing ring  118  that is received within annular recess  120  formed in top end cap  76 . Inner sealing ring  118  is adapted to provide a seal between annular top end connector  122 , which includes an annular body member  124  that is threadedly received at the upper end of tubular housing  104 . Sealing ring  118  serves to prevent water flow between the upper end of tubular housing  104 , top end connector  122 , and top end cap  76 . Connector  122  includes a downwardly-extending, coaxial sleeve  126  that carries on its outer surface a pair of O-rings  128  to sealingly engage with the upper inner surface of tubular sleeve  107 , and an upwardly-extending, coaxial sleeve  130  that carries on its inner surface a pair of O-rings  132  to sealingly engage with ultraviolet lamp cable connector  82  that extends from ultraviolet lamp  92 . Cable connector  82  is retained by an end fastener  134  that threadedly engages with cable connector  82  and top end connector  122  and that abuts the upper outer surface of top end cap  76 . The ultraviolet lamp assembly, which includes cable connector  82  and ultraviolet lamp  92 , can be removed from treatment element  90  by disengaging end fasteners  134  and lifting out the lamp assembly through the opening in top end connector  122 .  
      Top end cap  76  is threadedly received at the uppermost end of vessel  14 . An O-ring  136  provides a seal between vessel sidewall  60  and end cap  76  to prevent water leakage therebetween. A positive, water-tight seal is also provided between top end cap  76  and each of first filter element  84  and second filter element  86 ,  87  by sealing ring  114  and between top end cap  76  and top end connector  122  by inner sealing ring  118 . Each of sealing rings  114  and  118  is at least partially compressed when top end cap  76  is tightened against the upper end of vessel sidewall  60 . Top end cap  76  also includes a central opening to coaxially receive annular sleeve  130  of top end connector  122 . The disclosed structural arrangement allows top end cap to be threadedly engaged with or disengaged from vessel sidewall  60  while top end connector  122  remains stationary and secured to tubular housing  104  of third treatment element  90 .  
      Visible in  FIG. 4  are axial projections  78  that are provided to facilitate attachment to and removal from vessel  14  of end cap  76  for access to the filters and ultraviolet lamp for servicing purposes. Additionally, pressure relief valve  83  is provided in top end cap  76  to allow bleedoff of air that is trapped within vessel  14  after the application of top end cap  76 , and also to allow depressurization of the interior of vessel  14  after incoming water flow has been shut off, at a time when access to the treatment elements contained within vessel  14  is desired.  
       FIG. 4  also shows positioned at an end of tubular housing  104  a plurality of axially-elongated, circumferentially-spaced, openings in the form of slot-like passageways  138  to allow flow of filtered water from intermediate annular flow channel  88  into inner annular flow channel  100  to allow exposure of the filtered water to ultraviolet light for the third, disinfection stage of treatment. Passageways  138  are positioned adjacent the uppermost end of tubular housing  104  to cause the filtered water to enter inner annular flow channel  100  at its uppermost end and to flow axially substantially completely along quartz sleeve  106  for an extended exposure time of the water to ultraviolet light that emanates from lamp  92  for improved disinfection.  
       FIG. 5  is a cross-sectional view through vessel  14  adjacent to the lower end thereof to show the internal arrangement of the first and second filter elements  84 ,  86  and the third, disinfection element  90  including ultraviolet lamp  92 . Also shown are outer annular flow channel  74 , into which incoming water to be treated passes from inlet connection  26 , along with openings  94  in divider wall  72 ; intermediate annular flow channel  88  between second filter elements  86 ,  87  and tubular housing  104 ; and inner annular flow channel  100 , along with openings  110  that lead into outlet plenum  66 .  
       FIG. 6  is a cross-sectional view through vessel  14  between bottom wall  62  and divider wall  72 . As shown, inlet plenum  68  is of annular form and is separated from cylindrically-shaped outlet plenum  66  by axially-extending separator wall  70 .  
       FIG. 7  is a side view, partially broken away, showing first filter element  84  and second filter elements  86 ,  87  in assembled form to provide a unitary, tubular filter structure. Inner, second filter elements  86 ,  87  are surrounded by first filter element  84 , which is a semi-rigid, cylindrical filter pad formed from spun fibers. Tubular first filter element  84  is shown in a side view in  FIG. 8  and in an end view in  FIG. 9 .  
      Second filter elements  86 ,  87  are shown in  FIG. 10  in a side view, partially broken away, and in an end view in  FIG. 11 . As is apparent from  FIGS. 8 through 11 , first filter element  84  and second filter elements  86 ,  87  each have a tubular structure. First filter element  84  is placed around and in contact with the outer surfaces of each of second filter elements  86 ,  87 , providing a snug fit therebetween and assuring proper coaxial alignment of each of the second filter elements.  
       FIG. 12  shows a top view of vessel  14 . In addition to top end cap  76 , also shown in  FIG. 12  are the four axial projections  78  that extend upwardly from top end cap  76  and that define twist-off handles to allow removal of top end cap  76  from vessel  14  for servicing of the interior components that are housed within vessel  14 . Also shown is power cable  48  for supplying electrical power to the ultraviolet lamp.  
      In the operation of the above-described disinfection system, only periodic monitoring of control panel  30  is needed to determine whether the filter elements and ultraviolet lamp need replacement. Generally, for a typical home system that is sized for a maximum flow rate of about 12 gallons per minute and an average flow rate of about 4 gallons per minute, only annual carbon filter and lamp replacement is anticipated. The outer, particulate filter may require more frequent cleaning or replacement, depending upon the quality of the water being treated and the volume of water usage. The standard, low-pressure ultraviolet lamp generally operates at about 60° C. and therefore will not overheat. It can remain on continuously, even if no flow takes place over a number of days or weeks.  
      Although particular embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the present invention. Accordingly, it is intended to encompass within the appended claims all such changes and modifications that fall within the scope of the present invention.