Abstract:
A method of water purification by submicron filtration deploys a 6-way valve to periodically flush or clean the tubules in a predetermined selection of cleaning steps, some of which optionally introduce and then flush out chemical cleaning agents. The tubules are cleaned without disassembly of the filtration cartridge.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority to the US provisional patent application of the same title, filed on Apr. 23, 2007, having Application. Ser. No. 60/913,522, which is incorporated herein by reference. 
     
    
     BACKGROUND OF INVENTION 
       [0002]    The present invention relates to water purification by micro-filtration, and more specifically to a method of cleaning and using a micro-filtration system. 
         [0003]    When water is purified by micro-filtration it is pumped through a semi-porous membrane that has filter pore sizes small enough to block particulate mater that includes bacteria, yet permits water to pass through. A common configuration for such membranes is in the form of fibers or tubules that are hollow and have porous walls. Such tubules are assembled into bundles with a portion of the intervening space between them sealed at a top and bottom portion to form a common chamber. Typically this assembly is organized concentrically about a much larger hollow center tube with macro-perforations in the walls and packages in a cylindrical cartridge. In one configuration termed, “inside-to-outside” flow, water to be purified enters the tubules from above the upper seal at the top of the cartridge such that pure water then flows into the center tube, with the contaminants trapped inside the tubules. Alternatively, water can be pumped through the central tube against the outside of the tubes such that and the clean water is collected from inside the tubules after it flows into the portion of the cartridge above the upper seal, which is termed “outside-to-inside” flow. The flow type is usually specified by the cartridge manufacturer and can be dependent on the specific membrane configuration. The use of the term cartridge refers to both the exterior pressure vessel that contains fluid as well as the tubule array within, although the latter is frequently sold as a separate unit that interchanges in different pressure vessels. 
         [0004]    Eventually such micro-filtration systems become fouled when contaminants fill or plug the pores in the tubules and the tubules resist the flow of water there through. Prior methods of cleaning fouled micro-filtration cartridges involve using the flow of water along the tubules, on either the inside (for inside-to-outside” flow) or the outside (for “outside-to-inside” flow) to remove particulate to flush or hydro-dynamically push the particulate of the same side of the filter elements. Frequently some combination of a chemical attack of the fouling matter or particulate is used, which usually requires removal of the filter cartridge. 
         [0005]    Removing the filter for such cleaning is labor intensive, time consuming and requires the installation of either spare cartridges or a back up system. Fouling generally limits the use of micro-filtration to water that is already relatively consistently generally free of particulate. 
         [0006]    It would also be desirable to have a more effective means to clean fouling matter from the filter tubules. 
         [0007]    It would be desirable to provide a means of the micro-filtration of water that does not require the removal of the cartridges for cleaning. 
         [0008]    It is therefore a first object of the present invention to provide a means to clean the filtration element in situ without removal of the cartridge. 
       SUMMARY OF INVENTION 
       [0009]    In the present invention, the first object is achieved by providing a multi-way valve and distribution system that allows for flushing in the reverse direction of treatment, which is through the central outlet tube into the tubules. 
         [0010]    A second aspect of the invention is characterized in that chemical cleaning agent are introduced into the flushing effluent automatically in a controlled fashion without the need for additional pumps. 
         [0011]    The above and other objects, effects, features, and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1  is a schematic illustration of first embodiment of the submicron filtration system or apparatus. 
           [0013]      FIGS. 2A  and B illustrate processes of use of the apparatus of  FIG. 1  with different valve states. 
           [0014]      FIGS. 3A  and B illustrate alternative processes of use of the apparatus of  FIG. 1  with different valve states. 
           [0015]      FIG. 4  illustrates another alternative process of use of the apparatus of  FIG. 1  with different valve states. 
           [0016]      FIG. 5  A is a top plan view of the adapter  500 . 
           [0017]      FIG. 5B  is an exterior elevation of the adapter  500 . 
           [0018]      FIG. 5C  is a bottom plan view of the adapter  500 . 
           [0019]      FIG. 6  is a schematic illustration of an alternative embodiment of a micro-filtration system. 
           [0020]      FIG. 7A  is a top plan view of the plug/coupling used with the valve in  FIG. 6 . 
           [0021]      FIGS. 7B  and C illustrate the other orthogonal views of  FIG. 7A . 
           [0022]      FIG. 7D  is a top plan view of the plug/coupling used with the valve in  FIG. 8-13 .  FIGS. 7E  and F illustrate the other orthogonal views of  FIG. 7D . 
           [0023]      FIG. 8  is a schematic illustration of another alternative embodiment of the invention using two filter cartridges in which the first filter is operative while the second cartridge is in a stand-by mode. 
           [0024]      FIG. 9  is a schematic illustration of another mode of using the alternative embodiment of the invention of  FIG. 8  in which the second filter cartridge is operative while the first cartridge is being cleaned by a backwashing process. 
           [0025]      FIG. 10  is a schematic illustration of another mode of using the alternative embodiment of the invention of  FIG. 8  in which the second filter cartridge is operative while the first cartridge filter is being cleaned by a process that includes a chemical cleaning agent. 
           [0026]      FIG. 11  is a schematic illustration of another mode of using the alternative embodiment of the invention of  FIG. 8  in which the second filter cartridge is operative while the first cartridge filter is being cleaned by a rapid rinsing process. 
           [0027]      FIG. 12  is a schematic illustration of another mode of using the alternative embodiment of the invention of  FIG. 8  in which the second filter cartridge is operative while the first cartridge filter is in stand-by showing the process of refilling or making up the chemical cleaning agent used in  FIG. 10 . 
           [0028]      FIG. 13  is a schematic illustration of another mode of using the alternative embodiment of the invention of  FIG. 8  in which the second filter cartridge is operative while the first cartridge filter is in a stand-by mode. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Referring to  FIGS. 1 through 13 , wherein like reference numerals refer to like components in the various views, there is illustrated therein a new and improved method and apparatus for the purification of water and other fluids by sub-micron filtration and the cleaning/regeneration of associated sub-micron filtration membranes, generally denominated  100  herein. 
         [0030]    It should be understood that the term sub-micron filtration is intended to embrace the following terminologies and the attended particle size ranges listed in parenthesis: 1) Microfiltration (0.06-2.00 microns); 2) Ultrafiltration (0.02-0.2 microns); Nanofiltration (0.02-0.002 microns) and the like. 
         [0031]    In accordance with the present invention  FIG. 1  illustrates the inventive apparatus that comprises a controller  105 , multi-directional distribution valve  110 , adapter  500  and filtration unit  115 . The filtration unit  115  an inlet port  122  and an outlet port  121 . Filtration unit  115  has a central tube  116  that is in fluid communication with the space between filtration tubules  119  via holes  109 . Filtration tubules  119  are assembled to form a generally removable and replaceable filter cartridge or canister  117 . In the normal mode of operation of water purification for “inside-to-outside” flow, water to be purified arrives via inlet port  122  into the head space or sub chamber  118  above the opening to the filtration tubules  119 . Purified water passing through the sides of filtration tubules  119  passes into central tube  116  and out of filtration unit  115  via outlet port  121 . Adapter  500 , shown in  FIG. 5  provides the physical connection of source port  201  and product outlet port  202  to the distribution valve  110 . The multi-distribution valve  110  has a plurality of portals for inlet of water to be purified source port  201 , outlet of purified water or product  202 . Inlet  204  provides chemical cleaning agents, whereas port  203  is an outlet drain. It will be understood by one of ordinary skill in the art that the following description while specifically relating to “inside-to-outside” flow, is equally applicable to “outside-to-inside” flow, by reversing the inlet and outlet ports in the following descriptions and figures. 
         [0032]      FIG. 2-4  illustrates the states of the valves used in the water purification and regeneration processes.  FIG. 2A  illustrates the normal operation process  301 . In process  301 , controller  105  is operative to modulate the position of the valves in multi-distribution valve  110  such that water to be purified is directed by multi-distribution valve  110  from source port  201  to inlet port  122  and when purified from outlet port  121  to product outlet port  202  to be delivered as a product of the process. 
         [0033]    A multi-direction distribution valve  110  has a least four ports wherein 2 independent fluid streams flow through the valve at one time and operation of the valve between at least a first and second state redirects the independent fluid stream to alternative ports. 
         [0034]      FIG. 2B  illustrates a back wash process  302  with treated water. In process  302 , controller  105  is operative to modulate the position of the valves in distribution valve  110  such that fluid is directed by distribution valve  110  from source port  201  to outlet port  121  and from inlet port  122  to outlet drain  203 . This is deemed the most efficient means to remove debris form the porous wall of tubules  119 , as it is the reverse of the flow direction that eventually clogs the tubules. Filtered or treated water can be introduced into outlet port  121  for this cleaning process by turning 3-way valve  210  to admit pure water from a source  211  as shown by the adjacent arrow. It should be noted that the 3-way valve can be part of distribution valve  110 , or distribution valve can provide a similar function as is shown in the Figures. 
         [0035]      FIG. 3A  illustrates a first chemical cleaning process  303 . The specific type of cleaning chemicals will in large part depend on the primary nature of the membrane fouling material to be removed, as well as the chemical compatibility of membrane media and other filter components to cleaning chemicals, as is known to those of ordinary skill in the art. Typically such chemical cleaning agent may include without limitation; 1) caustic (NaOH) to increase solubility of solutes by hydrolysis and solubilization, 2) oxidants (such as NaOC 1 , H 2 O 2 , peroxyacetic acid) to oxidize natural organic material (NOM) and increase hydrophilicity by increasing the amount of oxygen containing functional groups such as carboxyl and phenolic groups, 3) acids (such as citric acid or nitric acid) and chelating agents like EDTA for the removal of scale compounds and metal oxides though solubilization and chelating, as well as 4) various proprietary formulations that may use these and other agents in combination, as well as surfactants and detergents. 
         [0036]    In process  303 , deemed down-flow chemical cleaning, controller  105  is operative to modulate the position of the valves in distribution valve  110  such that fluid is directed by distribution valve  110  from source port  201  to inlet port  122  and from outlet port  121  to outlet drain  203 . Thus, chemical cleaning solution is drawn into inlet port  122  from 204 by the Venturi effect. 
         [0037]      FIG. 3B  illustrates a second chemical cleaning process  304 . In process  303 , deemed up-flow chemical cleaning, controller  105  is operative to modulate the position of the valves in distribution valve  110  such that fluid is directed by distribution valve  110  from source port  201  to outlet port  121  and from inlet port  122  to outlet drain  203 . 
         [0038]      FIG. 4  illustrates rapid cleaning process  305 . In process  305 , controller  105  is operative to modulate the position of the valves in distribution valve  110  such that fluid is directed by distribution valve  110  from source port  201  to inlet port  122  and from outlet port  121  to outlet drain  203 . Thus, filtered/treated water is introduced into source port  201  via valve  210  from source  211 , such that is flows first through the tubules in the normal manner in  FIG. 2A , however now the effluent from outlet port  121  is directed to the drain. 
         [0039]      FIG. 5  illustrates the coupling adapter  500  that connects the distribution valve  110  to filtration unit  115 . Coupling adapter  500  has a central circular channel  505  surrounded by a separate co-axial cylinder having a plurality of holes  504  through coupling adapter  500 . The upper threaded fitting  501  screws into a conventional control valve distribution valve  110  used in automated water softening equipment, while in contrast the lower neck  502  and the flange  503  are adapted to couple and seal with conventional filtration unit  115 . Specifically, lower neck  502  seals the central circular channel  505  with central tube  116  to isolate the fluid communicate from sub chamber  118 . Flange  503  seals with filtration unit  115  to provide fluid communication from distribution valve  110  to sub chamber  118  via the plurality of holes  504  in Flange  503 . 
         [0040]    Thus, the use of adapter  500  with conventional and commercial distribution valve  110 ,  105  and filtration unit  115  to form device  100  permits cleaning and in particular chemical cleaning automating without removing canister  117  of filtration tubules  119 , the controller can be used to automatically clean the filtration tubules  119  on a periodic basis depending on the contaminant and nature of the particulate matter in the water to be treated. Thus, in such a mode process  301  may run for hundreds of hours with cleaning processes  302 ,  303 ,  304  and/or  305  periodical running for just a few hours as needed to clean and or rejuvenate filtration tubules  119 . Anticipated use/cleaning sequences are  301 / 302 / 303  (and/or  304 )/ 305 . Alternatively, the sequence  301 / 302 / 303  (and/or  304 )/ 302 / 305  is also anticipated to provide the benefits of increasing the available time for process  301 , water purification, with minimum non-productive time in processes  302 - 305 . 
         [0041]      FIG. 6  is a more preferred embodiment of the invention using a Pentair Fleck  9100 . The controller  105  (not shown in this figure) is operative to direct fluid in the multiple directions illustrated in  FIG. 1-5 . Additional ports to valve  110  are covered by plugs  207 . 
         [0042]      FIG. 7A-C  illustrate in orthogonal isometric views plug  207  shown in  FIG. 6 .  FIG. 7D-E  illustrate in orthogonal isometric views the threaded adapter  208  used to connect the portal  205  and  206  of the first multi-directional distribution valve  110  to the portal  202 ′ and  201 ′ respectively of the second distribution valve  110 ′, as shown in  FIG. 8 . 
         [0043]    In accordance with another embodiment of the present invention,  FIG. 8  is a system configured for continuous operation where one cartridge is always in operation when the other is being cleaned, regenerated or replaced. 
         [0044]    As in  FIG. 1  and  FIG. 6  second filtration unit  115 ′ has an adapter  500  such that it is in variable fluid communication with distribution valve  110  via a second distribution valve  110 ′. Distribution valve  110  has a second exit portal  205 , and a second inlet portal  206 . The exit portal  205  of distribution valve  110  is connected to the inlet portal  201 ′ of distribution valve  110 ′. The second inlet portal  206  is connected to the exit portal  202  ‘of the second distribution valve  110 ′. 
         [0045]    In  FIG. 8  distribution valve  110  is operative to close portal  205  and  206  so that cartridge  115 ′ is in a “stand-by” mode, with cartridge  115 ′ operative in the same fashion as described with respect to previous embodiments, that is raw water enters distribution valve  110  via portal  201  and pure water exits via portal  202 . 
         [0046]      FIG. 9-13  Illustrate alternative modes of using dual filtration unit system of  FIG. 8 . X shows the conditions when a portal is closed by the distribution valve  110  or  110 ′ and arrow show the direction of fluid flow between the portals, the cartridges  115  and  115 ′ and outside connections. 
         [0047]    In  FIG. 9 , cartridge  115 ′ continuously filters incoming raw water via portal  201 ′, returning purified water or fluid via portal  202 ′ to distribution valve  110 , via portal  205 . Simultaneously cartridge  115  is cleaned by backwashing as distribution valve  110  is operative to direct incoming raw water from portal  201  to  201 ′, and purified water from portal  202 ′ to portal  202 . However, the distribution valve  110  is also operative to divert a portion of the purified water from portal  205  to outlet port  121 , with the backwashed water exiting portal  202  via drain  203 . 
         [0048]    In  FIG. 10 , chemical cleaning agent is drawn into cartridge  115  from chemical cleaning agent tank  238  while cartridge  115 ′ is in service. The distribution valve  110  is operative to direct a portion of purified water from portal  205  to outlet port  121 , while at the same time opening the connection to the chemical feed tank  238  via portal  204  such that stream of fluid into outlet port  121  downstream of portal  205  draws fluid from the cleaning tank via a Venturi effect into cartridge  115 . The fluid exiting cartridge  115  is then diverted by distribution valve  110  to  203 . 
         [0049]    In  FIG. 11 , cartridge  115 , it is rapidly rinsed after chemical cleaning while cartridge  115 ′ is in service. This is achieved by closing off the flow from portal  204 , such that a portion of the purified water flowing from portal  205  to portal  202  is feed into cartridge  115  via inlet port  122 . 
         [0050]    In  FIG. 12 , the chemical feed tank  238  is partially filled with water to dilute the cleaning solution to its working concentration. A concentrated chemical cleaning solution or solid agent is placed in tank  238  before connection to portal  204 . 
         [0051]    In  FIG. 13 , cartridge  115 ′ is operative, while cartridge  115  is in standby mode, having been cleaned by the procedures shown in  FIG. 8-12 . 
         [0052]    While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be within the spirit and scope of the invention as defined by the appended claims.