Abstract:
The invention consists in a disposable module ( 31 ) for purifying a fluid, in particular water, adapted to form part of a thud purification system and comprising fluid purification means ( 25, 28 ), a housing ( 35 ) in which the purification means are housed, and means for removably connecting the purification module ( 31 ) to the purification system to establish fluid communication between the purification system and the purification module ( 31 ), characterized in that the housing ( 35 ) contains from the outset a cleaning agent ( 36 ) disposed to come into contact with the fluid caused to circulate inside the housing ( 35 ) to clean at least a portion of the purification system, it also consists in the purification system and corresponding fabrication and cleaning methods.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/249,713, filed Sep. 30, 2011, which issued as U.S. Pat. No. 8,551,261, on Oct. 8, 2013, and which is a divisional of U.S. patent application Ser. No. 10/571,738, filed Mar. 14, 2006, which is a 371 of PCT/IB12004/003724 filed on Oct. 2, 2004, which claims priority of French Patent Application No. 0312675, filed on Oct. 29, 2003, the disclosures of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to cleaning a system for purifying a fluid, in particular water, to which at least one module for purifying the fluid is connected or this purpose. 
     It is aimed more particularly at systems combining means for effecting a purification pretreatment of the fluid, such as activated charcoal, polyphosphates or front filtration members, and means for effecting a purification treatment of the fluid by tangential filtration, such as reverse osmosis or ultrafiltration cartridges housed in one or more modules arranged in series in the system. 
     BACKGROUND OF THE INVENTION 
     To guarantee correct operation of the system, it is necessary to clean, and in particular to disinfect, the component parts regularly, in particular the purification means employing tangential filtration. 
     In one prior art arrangement, using a message displayed on a screen, the system regularly prompts the user to introduce a cleaning agent into the system via an orifice of the system communicating with a pipe through which the fluid passes or an orifice formed in the receptacle of a purification module that may be recycled, i.e. a module in which the purification means housed in the receptacle, such as the reverse osmosis cartridge, for example, are replaced periodically. 
     On this occasion, the user is obliged to handle the cleaning products, for example tablets containing soda or chlorine, which are generally harmful to humans because of their caustic, irritant, toxic, etc. nature. 
     Another prior art system described in U.S. Pat. No. 6,074,551 is provided with a device which, during a cleaning cycle, automatically injects an acidic or basic solution into a recycling pipe supplying one or more reverse osmosis modules with water to be purified. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention aims generally to improve the systems referred to above. One particular object of the present invention is an arrangement for ensuring the safety of the user at the lowest cost. 
     To be more precise, a first aspect of the present invention consists in a disposable module for purifying a fluid, in particular water, adapted to form pan of a fluid purification system and comprising fluid purification means, a housing in which the purification means are housed, and means for removably connecting the purification module to the purification system to establish fluid communication between the purification system and the purification module, characterized in that the housing contains from the outset a cleaning agent disposed to come into contact with the fluid caused to circulate inside the housing to clean at least a portion of the purification system. 
     In other words, the invention exploits the possibility of using, disposable modules, and this of replacing them periodically, to introduce a cleaning agent into the fluid purification system to clean at least part thereof. 
     As a result, the fluid purification system is cleaned by applying very simple measures, with the benefit accost reduction. 
     Furthermore, the cleaning process may be effected safely since the module supplied to the user already contains the cleaning agent. 
     This results in a module that not only purifies the fluid but also distributes the cleaning agent into at least a portion of the module itself and/or at least a portion of the remainder of the fluid purification system. 
     According to preferred, and where applicable combined, features of modules conforming to the invention: 
     the housing may not be demounted; 
     the cleaning agent is disposed between an inlet for fluid to be treated formed in the housing and the purification means or between the latter and a purified fluid outlet thrilled in the housing; 
     the cleaning agent is housed in a space created for this purpose in the housing, in particular a recess in a raised portion of the housing; 
     said space is delimited by retaining means for the cleaning agent preferably taking the form of a cage, in particular an added cage; 
     the housing contains tangential filtration purification means, in particular purification means employing reverse osmosis, nanofiltration, ultrafiltration or microfiltration; 
     the housing contains fluid purification pretreatment means upstream of the purification processing means, where applicable tangential filtration purification processing means, and the cleaning agent is disposed between the pretreatment means and the purification treatment means or between the later and a purified fluid outlet formed in the housing; 
     the pretreatment means are selected from the group comprising ion exchanger activated supports or resins, activated charcoal, chlorine reduction agents, in particular alloys such as copper-zinc formulations (in particular of the KDF® type from FLUID TREATMENT INC.), front filtration members, tartar formation reduction agents, in particular polyphosphates, and combinations of the above; 
     the cleaning agent comprises a chemical compound or an association of chemical compounds for destroying a biofilm and/or having a bactericidal effect and/or for eliminating organic and/or mineral soiling. 
     The invention has the farther advantage of enabling the use of cleaning agents taking forms as diverse as powders, crystals, granules, tablets, where applicable coating or constituting the contents of capsules or sachets that dissolve or split in contact with the fluid, or in the form of a liquid constituting the content of an enclosure that is split in contact with the fluid. 
     The cleaning agent is preferably a chlorinated product, an organochlorinated product, an oxidizing product, an acid, a base or a disinfectant solution. 
     In practice, the cleaning agent is preferably bleach, a chloramine, hypochloric acid, hypochlorous acid, citric acid, tartaric acid, acetic acid, perchloric acid, peracetic acid, a salt of any of the above acids, sodium hydroxide, potassium hydroxide, potassium permanganate, potassium dichromate or to disinfectant solution containing hydrogen peroxide and peracetic acid or organic complexes including silver salts. 
     Furthermore, the arrangement of the invention advantageously lends itself to an improvement whereby the casing comprises means allowing the module to be identified by the fluid purification system, whereby the latter may, for example, start a cleaning cycle automatically, i.e. without the user having to start the cycle manually, for example by pressing a key of control means of the system. 
     The invention also consists in it system for purifying a fluid including, at least one fluid purification module as defined above. 
     It further costs in a method of fabricating the above kind of module, including mounting purification means in a casing, characterized in that it further includes placing, a cleaning agent inside the casing before closing it. 
     The invention further consists in a method of cleaning at least a portion of a fluid purification system, characterized in that it includes the steps of connecting a disposable fluid purification module as defined above to the fluid purification system and then starting a system cleaning procedure, where applicable starting said cleaning procedure automatically following identification of the module by the system by means of the identification means. 
    
    
     
       The features and advantages of the invention will emerge further from the following description, which is given by way of example and with reference to the appended diagrammatic drawings, in which: 
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic representation of the configuration of a fluid purification system using a fluid purification module according to the invention, and 
         FIGS. 2 to 5  represent other embodiments of a fluid purification module of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the embodiment shown, a water purification system  10  according to the invention for purifying water comprises, in a manner that is known in the art, a pretreatment module  11  and a reverse osmosis module  12  downstream of the pretreatment module  11 . 
     The reverse osmosis module  12  is not in itself relevant to the present invention and is not described in detail here. 
     Suffice to say that, in the embodiment shown, it is of the same kind as the TW30 module from DOW CHEMICAL®. 
     In practice, in this kind of reverse osmosis module  12 , the flow of water to be purified is continuous and tangential relative to dense membranes of the module, so that the water to be purified is divided at the membranes into two portions with different concentrations: 
     a portion that passes through the membranes and is known as the permeate, and 
     a portion that does not pass through the membranes, is known as the retentate, and contains ions, molecules or particles retained by the membranes, in particular mineral ions. 
     Thus the water produced by a system  10  of the above kind may be considered to have a very low level of dissolved salts (i.e. to be ultrapure water). 
     In the embodiment shown, the water to be purified comes from the drinking water main, for example, and is fed to the pretreatment module  11  via an inlet pipe  13 . The water leaving the pretreatment module  11 , after undergoing a purification pretreatment therein, is fed to the reverse osmosis module  12  via a supply pipe  14  of the latter. This is also known in the art. 
     At the outlet from the reverse osmosis module  12 , the permeate (i.e. the ultrapure water) is evacuated via an evacuation pipe  15  and the retentate is fed to the outlet of the water purification system  10  via a retentate (i.e. rejected water) evacuation pipe  16 . 
     The evacuation pipe  16  comprises a restriction  17 , i.e. a component reducing the water flowrate and creating a pressure drop in the vicinity of the outlet of the evacuation pipe  16 . This is also known in the art. If necessary, the restriction  17  may be bypassed by means of a bypass pipe  18  provided with a shunt valve  19 . 
     As is the case in the embodiment shown, in accordance with the invention, the water purification pretreatment module  11  comprises a housing  20  containing purification pretreatment means, which here take the form of grains of activated charcoal  21 , and a cleaning agent  22  disposed between the pretreatment means  21  and the outlet  23  of the module, to which the supply pipe  14  of the reverse osmosis module  12  is connected. 
     To be more precise, the water purification pretreatment module  11  comprises a housing  24  in which the cleaning agent is placed from the outset so that it is in the flow path of water inside the casing  20  and therefore dissolves in contact with the water and thus cleans all of the portion of the water purification system  10  that is downstream of the water purification pretreatment module  11 , in particular the reverse osmosis module  12 . 
     To this end, in the embodiment shown, the cleaning agent  22  in practice takes the form of a chlorinated tablet, as is known in the art, whose role is to destroy bacteria and prevent their proliferation downstream of the pretreatment module  11 , and in particular in the reverse osmosis module  12 , that is to say, more generally, to disinfect this portion of the water purification system  10 . 
     It should also be noted that the casing  20  comprises means, not shown, for identification of the module  11  by the water purification system  10 , which enables the latter to start a cleaning cycle automatically after connection of the pretreatment module  11  to the remainder of the water purification system  10  and recognition of the module  11  by the system  10 . 
     The cleaning agent may be placed elsewhere, for example in other embodiments of the water purification module, and in particular: 
     1) As shown in  FIG. 2 , downstream of a filter cartridge  25  of the kind comprising a perforated tube  26  surrounded by an annular layer  27  of filter material and preceded by a mass  28  of filter material, activated charcoal grains in this example, with which there is fluid communication via a passage  29  formed in the bottom  30  of the module  31 . The mass of filter material  28  is retained by separator members  32  and is in fluid communication with an inlet  33  for fluid to be purified that is provided in a cover  34  of the cylindrical casing  35  of the purification module  31  shown in  FIG. 2 . Here the cover  34  is welded or stuck to the casing  35  so that it may not be removed. 
     The cleaning agent tablet  36 , which is also a chlorinated tablet here, is disposed in a housing  37  especially provided for this purpose in the housing  35  between the cartridge  25  and a purified fluid outlet  38  formed in the cover  34  of the housing  15 . It is clamped in place between the upper end of the tube  26  of the filter cartridge  25  and the cover  34  of the housing  35 . 
     An O-ring  39  provides a seal between the inlet and the outlet of the filter cartridge  25 . 
     2) In the embodiments shown in  FIGS. 3 and 4 , the module is similar to that shown in  FIG. 2 , but the module  40  or  41  contains only one cartridge of the kind shown in  FIG. 2 , and it may be seen that a cleaning agent tablet, also of the kind shown in  FIG. 2 , may be placed either (i) in an existing free space  42  in the module  40 , either in the immediate vicinity of the inlet  43  for water to be purified ( FIG. 3 , tablet  44 ) or further downstream in the water flow passage ( FIG. 3  tablet  45 , sandwiched between the bottom end of the cartridge  46  and the bottom  47  of the housing  48  of the module  40 ), or (ii) in a free space  49  between the upper end of the cartridge  50  and an outlet  51  for water to be purified from the housing  52  of the module  41  ( FIG. 4  tablet  53 ). 
     In connection with  FIG. 3 , it should be noted that a plurality of tablets may be placed in the same module. 
     What is more, in the embodiments shown in  FIGS. 3 and 4 , it is interesting to note that the tablets are held in place by the existing structural members of the housing and, where applicable, by the member that it contains. 
     Finally, in the embodiment shown in  FIG. 5 , a tablet  54  is placed in the passage  55  for the flow of water coming from the pretreatment means  56  there grains of activated charcoal) and entering a reverse osmosis cartridge  57 . It is placed in a space  58  created for this purpose that is simply molded in one piece with the housing  59  of the module  60 , which has cost benefits. 
     In further embodiments, the tablet may be disposed in a recess formed in an upstanding portion of the housing, in a cage added to or separate from the housing, etc. 
     Note further that the means for connecting the modules removably to the purification system, for them to form an integral part thereof and to establish water communication between the latter and the module and vice-versa, are not shown in the figures. For example, they may be means of the kind described in European patent application EP-A-0 818 228 in the name of Niermeyer et. al. 
     In all other respects, these modules are of conventional structure: they are therefore not described in more detail here. 
     As may be seen in  FIGS. 1 to 5 , none of the housings  20 ,  35 ,  48 ,  52  and  59  described here has an opening for introducing cleaning agent into the interior thereof subsequent to its production. 
     It must further be noted that in practice all the modules that have just been described may be equipped with means for identification of the module by the fluid purification system, thanks to which the latter may, for example, start a cleaning cycle automatically after connection of the module to the system and identification thereof by the system. 
     Finally, it should also be timed that chlorinated tablets may be replaced by any other type of cleaning agent of the kind defined hereinabove and that the treatment and pretreatment means used hi the embodiment shown in  FIGS. 2 to 5  may equally be replaced by other, corresponding means, also of the kind defined above. 
     Of course, the present invention is not limited to the embodiments described and shown, and encompasses any variant execution thereof.