Patent Publication Number: US-2007102357-A1

Title: Heat sanitization for reverse osmosis systems

Description:
BACKGROUND  
      The present invention relates to a system for sanitizing reverse osmosis systems and, more particularly, to a system for utilizing the pure water produced by the reverse osmosis system to sanitize that system by heating that pure water to an elevated temperature and circulating that heated, pure water selectively through flow paths of the reverse osmosis system.  
      Reverse osmosis systems, in general, produce pure water that is used in dialysis. machines, normally with an additive such as sodium bicarbonate. The pure water is circulated through various apparatus, components and conduits and the like in order to provide that pure water to individual dialysis machines. A problem therefore arises in that the apparatus, components and conduits can become contaminated with harmful matter, that is, there can be present bacteria, glucans and the like can affect the pure water circulated therein and downgrade the purity of that water. The bacteria fragments can trigger T-helper cells to create C-reactive proteins that are suspected to lead to cardio-vascular disease, arthritis and carpal tunnel syndrome, among other ailments. It is, therefore, necessary to periodically clean the flow paths through the various apparatuses, components and conduits to eliminate the problem so as to assure that only pure water is produced and circulated through the dialysis machines.  
      One current method of carrying out that cleaning process is to utilize chemical agents that are circulated through the various flow paths of the dialysis system, however, there is also a downside with such method in that it then becomes necessary after the cleaning with chemical agents has been completed, to then rid the flow paths of the chemical agents themselves, since those chemical agents can be a source of contamination and harmful to the supply of the pure water. As such, the use of chemical disinfectants is a procedure that is costly, time consuming and difficult. Accordingly, while the use of chemical agents alleviate the contaminant problem, the chemical agents thereupon become another source of contamination that must be thoroughly removed before the reverse osmosis system can again supply pure water to the dialysis machines.  
      The water being produced by the reverse osmosis system, as stated, is pure and therefore is a good medium to carry out the sanitizing function and, as a standard, such water is capable of producing sufficient cleaning if utilized at a temperature of 80 degrees C. for a period of at least about ½ hour. Some systems have suggested the use of heated water in a pasteurization system to clean components and conduits of a reverse osmosis system, see U.S. Pat. No. 6,251,279 of Peterson et al, however, in such system, only a portion of the system is disinfected and there is no versatility or selection on the part of the user to clean one or more selected flow paths in the system.  
      Accordingly, it would be advantageous to have a system that uses the pure water normally produced by the reverse osmosis system to sanitize the system, either in its entirety or by means of certain selected portions and components of the reverse osmosis system.  
      SUMMARY OF THE INVENTION The present invention relates to a sanitizing system for use with a reverse osmosis system where the water that is purified by the reverse osmosis system is collected in a storage tank. During a sanitizing cycle, the pure water held with the storage is removed, heated to the sanitization temperature and then circulated through one or more selected flow paths in the reverse osmosis system including a path that passes through the reverse osmosis membrane unit, the delivery conduit having connections to supply water to the dialysis machines and the like. The reverse osmosis system as well as the sanitizing system is constructed of materials that are compatible with the high temperatures and pressures used in the sanitizing cycles of the present invention.  
      By the present system, the user can select one or more individual flow paths or there is a control system that can carry out an automatic selection of the flow path or flow paths for the sanitization process by opening and closing the appropriate valves and components to pass the heated, pure water though the selected flow path or flow paths. The control system can also be utilized to operate the sanitizing cycles automatically, such as by a timer that initiates one or more of the sanitizing cycles at a predetermined time of day i.e. when the dialysis machines are likely to be inactive or a predetermined time interval i.e. once a week. The control system can then initiate the sanitizing cycle in any order determined by the user and carried out automatically.  
      In an exemplary embodiment, the heating of the pure water removed from storage tank is carried out at a predetermined maximum rate so that a rapid change of temperature does not create a thermal shock to the system. As such, the heater can heat the pure water at the rate of between about 1-5 degrees C. per minute so that the heating of the water used in the sanitizing cycle is gradually heated up to the sanitizing temperature at a relatively slow, controlled rate. In addition the temperature is controlled to assure that there is a maximum allowed temperature during the sanitizing cycles, preferably about 99 degrees C. such that the particular sanitizing cycle is discontinued prior to adding enough energy to overcome the latent heat of vaporization.  
      With each of the sanitizing cycles for the various flow paths, there is also a cool down cycle, again which may be selective as to a desired flow path or flow paths, that circulates the cooler water through the flow paths to flush and cool the flow paths and which allows the heated water from any of the sanitizing cycles to be discharged into a municipal or other system at a temperature that will be acceptable to that system.  
      These and other features and advantages of the present invention will become more readily apparent during the following detailed description taken in conjunction with the drawings herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic view of a reverse osmosis system illustrating the various components used in that system during the normal function of the system in producing pure water for use in dialysis machines;  
       FIG. 2  is a schematic view of a reverse osmosis system illustrating the heat sanitization tank fill cycle used in the operation of the sanitizing system of the present invention;  
       FIG. 3  is a schematic view of a reverse osmosis system illustrating the loop and dialysis machines heat sanitization cycle used in the operation of the sanitizing system of the present invention;  
       FIG. 4  is a schematic view of a reverse osmosis system illustrating the reverse osmosis and loop sanitization cycle used in the operation of the sanitizing system of the present invention;  
       FIG. 5  is a schematic view of a reverse osmosis system illustrating the reverse osmosis heat sanitization cycle used in the operation of the sanitizing system of the present invention;  
       FIG. 6  is a schematic view of a reverse osmosis system illustrating the loop cool down cycle used in the operation of the sanitizing system of the present invention;  
       FIG. 7  is a schematic view of a reverse osmosis system illustrating the reverse osmosis and loop cool down cycle used in the operation of the sanitizing system of the present invention; and  
       FIG. 8  is a schematic view of a reverse osmosis system illustrating the reverse osmosis cool down cycle used in the operation of the sanitizing system of the present invention 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring now to  FIG. 1 , there is shown a schematic view illustrating the normal operation of a reverse osmosis system having the sanitizing system of the present invention incorporated there into. As can be seen, there is an inlet  10  for water and, in the embodiment shown, the inlet comprises a hot water inlet  12  and a cold water inlet  14  and a mixing valve  16  that receives the water from the hot and cold inlets  12 ,  14  to arrive at a flow of water at a desired temperature, such as 25 degrees C. that enters conduit  18 . A feed pump  20  raises the pressure of the water to about 45 psi and the water is thereafter passed, by means of conduit  22  through a pretreatment section that preferably includes a plurality of carbon filters  24  and a water softener  26 .  
      In the exemplary embodiment, three carbon filters  24  are shown and which allows the normal system to bypass one of the carbon filters so that it will remain dry and available for use in the event of a failure of one of the carbon filters in use or in the event one of the carbon filters  24  is simply scheduled to be out of service for normal maintenance.  
      The thus treated water then passes through an open valve  28 , heater pump  30  and a heater  32  and enters conduit  34  to pass through an open valve  34  where the water, in conduit  38  splits into inlet conduits  40 ,  42  at a tee  44 . As also can be seen there are pair of reverse osmosis units  46  and  48  that are connected, respectively to inlet conduits  40  and  42  through valves  50  and  52 . The reverse osmosis units  46 ,  48  are constructed with the same components and both have inlet conduits  40  and  42 , and outlet conduits  54 ,  56 . Since the components are the same, only one of the reverse osmosis membrane units will be explained and like numbers will be used for the corresponding components.  
      Taking, therefore, the reverse osmosis unit  46 , the water enters via the inlet conduit  38 , valve  50  and passes through a high pressure pump  58  where the pressure of the water is raised to about 235 psi. The pressurized water is then passed through a series of membrane vessels  60 ,  62 ,  64  where the reverse osmosis takes place to purify the water. The materials of the reverse osmosis units as well as other components that are subjected to the elevated temperatures of water used in carrying out the present invention, such as the membranes, membrane housings, pumps, conduits, fittings, valves, instruments and the like are designed to withstand that temperature. For example, the membranes used in the reverse osmosis unite are cast in polyamide material and constructed in a thin film composition configuration and also, to withstand the elevated temperatures, the membranes are manufactured with special adhesives, permeate tubes and connectors.  
      As is known, while three membrane vessels are disclosed in the exemplary embodiment, there may be a greater or lesser number of membrane vessels depending, generally, on the number of dialysis machines that are being supplied with the pure water. Normally, the number of membrane vessels may range from one to about fourteen vessels. The is also, normally a feedback loop  66  in order to maintain a constant flow of water through the membrane vessels  60 ,  62 ,  64 . There is also a drain conduit  68  terminating in a drain  70  for the membrane vessels  60 ,  62 ,  64 .  
      Accordingly, the water is purified as it pass through the membrane vessels  60 ,  62 ,  64  and the pure water is passed to the outlet conduits  54 ,  56  where the pure water enters a dialysis conduit  72  through valves  74 ,  76 , where there are connections  78  for providing fluid connections to individual dialysis machines (not shown). The valves  74 ,  76  enable the system to direct the water from either or both of the reverse osmosis units  46 ,  48  to the dialysis conduit  72 . By such means, either of the reverse osmosis units  46 ,  48  can be on stream while the other can be off stream for maintenance, or the like, so that there is no downtime in the use of the reverse osmosis system during maintenance. Continuing, the water is returned via the dialysis conduit  72  through open valve  80  to the conduit  22  for recirculation.  
      As has now been explained, the reverse osmosis system provides the pure water, as described, in order to supply the pure water necessary for the functioning of the dialysis machines.  
      The sanitizing system therefore can be described and which is utilized to selectively pass heated, pure water through one of more of the previously described paths of water through the reverse osmosis system. The various selective cycles are hereafter described individually. In the operation of al of the following cycles, as well as the overall control of the reverse osmosis system itself, there is a control system  82  having a central processing unit (CPU) that is used to control the various valves, proved a control of power to the components, including pumps and the like and which can be controlled by an input  84  from a user to carry out the settings of valves for all of the cycles to be explained. Thus, the valves hereinafter discussed are controllable by means of an electrical signal that is, in turn, controlled by the control system  82  as well as the operations of the other electrically controlled components.  
     Heat Sanitization Tank Fill Cycle  
      Turning now to  FIG. 2 , taken along with  FIG. 1 , there is shown a schematic view of the various components illustrated in  FIG. 1  that are employed during the heat sanitization tank fill cycle. As can be seen, the use of the pretreatment is similar to the normal functions as described in  FIG. 1 , and the same reference numbers used, that is, the water enters the system in the normal manner and passes through the carbon filters  24  and the water softener  26 . The water continues by passing through the conduit  22 , through the heater pump  30  and the heater  32 , through the conduit  34 , through open valve  36  and through the conduit  38  where the water enters into one of the reverse osmosis units  46  or  48 . Taking the reverse osmosis unit  46  as an example, the water then progresses through the outlet conduit  54 , the open valve  76 , and the dialysis conduit  72 . The water thereafter flows to a storage tank  86  through open valve  88 , it begin noted that valve  80  has now been closed. As such the pure water, having passed through reverse osmosis unit  46  fills the storage tank  86 .  
      The storage tank  86  may, during the normal operation of the reverse osmosis system, be empty so as to conserve water as well as avoid a likely location for the growth of bacteria. However, alternatively, there may be instances where the user wants to collect pure water in the storage tank  86  for other purposes and, as such, the storage tank  86  may initially contain a quantity of pure water. Accordingly, by the use of the heat sanitization tank fill cycle, the storage tank  86  is filled with pure water and the level of the water can be monitored by a sensor, not shown, such that the filling of the storage tank  86  can be automatically terminated when the desired quantity or level of water is present in the storage tank  86 . It should be noted that, during the heat sanitization tank fill cycle, the heater  32  is not energized and the heater pump  30  is also not in operation. In addition, the dialysis machines are disconnected from the connections  78  or otherwise not in fluid connection with the dialysis conduit  72  so that the water does not enter into any of the dialysis machines.  
     Loop and Dialysis Machines Heat Sanitization Cycle  
      Turning now to  FIG. 3 , there is shown a schematic view of a loop and dialysis machine heat sanitization cycle of the present invention. With the storage tank  86  filled to the desired capacity with pure water, the operation of the sanitization cycles of the present invention can be explained. As can be seen, the valve  28  is closed, thereby shutting off the supply of water from the inlet  10 . Valve  90  is opened so that the water can exit the storage tank  86  to be used in the sanitization process. That pure water from the storage tank  86  is pressurized by the heater pump  30  that has been activated and the pressurized water passes through the heater  32  where it is heated to the desired sanitization temperature.  
      As shown, the heater  32  is a separate component, however, the heater  32  can be incorporated into or located within the storage tank  86  so as to heat the water contained within the tank  86  to the sanitization temperature and then routed to the heater pump  30 . The heater  32  itself can be any one of a variety of heaters, such as an electric heater, a steam heater or the like and is, as discussed, controlled by the control system  82 . Accordingly, in the control of the heater  32 , the control system  82  can continuously monitor the temperature of the water leaving the heater and control the temperature to the desired level. In addition, the control system  82  can cause heater  32  to heat the water at a predetermined maximum rate, that is, in order to prevent a rapid change in the water temperatures through the various flow paths in the reverse osmosis system, thereby creating a thermal shock, the heater  32  is controlled so that the temperature of the water is raised at the maximum rate of 5 degrees C. per minute. The control of the ultimate desired temperature, that of about 80 to 85 degrees C. can be controlled by having a temperature sensor at or proximate to the inlet and outlet of the heater  32  so that the control system  82  can sense both temperatures and adjust the heater  32  accordingly to provide the desire heating rate as well as the ultimate temperature of the heated water.  
      Continuing the cycle, the hot, pure water is carried by conduit  34  to valve  36  which is now closed and valve  92  opened such that the water can directly enter the dialysis conduit  72  where it continues through that conduit and returns to the storage tank  86  through the open valve  88 . As such, the heated, pure water has, during that cycle passed through the dialysis conduit  72  to sanitize that flow path through the reverse osmosis system. As indicated, the flow of the heated, pure water is controlled by the control system  82  for a sufficient period of time that the flow path is sanitized by the pure heated water. During this cycle it is also possible to pass the heated, pure water through one or more of the dialysis machines that are fluidly connected to the dialysis conduit  72  through one or more of the connections  78  so that the dialysis machines themselves can be sanitized and the control system  82  can provide a signal to the personnel attending to the dialysis machines to alert that personnel that the dialysis machines can be attached to the connections  78  during this cycle.  
      As described, this cycle circulates the heated, pure water through a selected portion of the flow path or flow paths through the overall reverse osmosis system and the particular flow path can be selected by the user and entered by means of the input  84  to the control system  82  that then opens and closes the various valves to carry out the selective cycle for sanitization of the particular flow path. Thus, as will be seen with the input  84  to control system  82 , the user can select one of the flow paths individually or all of the flow paths simultaneously for circulation of the heated, pure water by means of the control system  82  that operated the particular valves and controls the heating of the pure water in accordance with the user&#39;s input. Alternatively, of course any one or more of the sanitization cycles can be commenced by a timer such that the use merely initiates a sanitization cycle and the system carries out one or more cycles based on a timer.  
      As a still further alternative, even the initiation of the sanitization cycle can be by a timer such that the system undergoes a time sanitization cycle, for example, once a week, without the intervention of the user and such cycling would normally be initiated by the timer at times when the dialysis machines are not normally in use.  
     Reverse Osmosis and Loop Heat Sanitization Cycle  
      Turning now to  FIG. 4 , there is shown a schematic view of the reverse osmosis and loop heat sanitization cycle of the present invention. When this cycle is selected, the reverse osmosis units and the loop having the connections  78  to the dialysis machines are heat sanitized. Again, as with the prior sanitization cycle, the valve  28  is closed, thereby shutting off the supply of water from the inlet  10 . Valve  90  is opened so that the water can exit the storage tank  86  to be used in the sanitization process. That pure water from the storage tank  86  is pressurized by the heater pump  30  that has been activated and the pressurized water passes through the heater  32  where it is heated to the desired sanitization temperature and at the desired rate.  
      Continuing the cycle, the hot, pure water is carried by conduit  34  through the open to valve  36 , valve  92  being closed, such that the water passes along conduit  38  to tee  44  where the water can then pass though both of the inlet conduits  40 , and  42  since both valves  50  and  52  are open so that the heated, pure water can enter and continue through both of the reverse osmosis units  46 ,  48  to heat sanitize those units and the water can continue through the outlet conduits  54 ,  56 , through now opened valves  74  and  76  to enter the dialysis conduit  72  where it continues through that conduit and returns to the storage tank  86  through the open valve  88 . During this cycle, the high pressure pump  58  is not energized since there is no need for the high pressure for the water to pass through the membrane vessels  60 ,  62 ,  64 .  
      As such, the heated, pure water has, during that cycle, passed through the dialysis conduit  72  as well as both of the reverse osmosis units  46 ,  48  to sanitize that flow path through the reverse osmosis system. Again, the flow of the heated, pure water is controlled by the control system  82  for a sufficient period of time that the flow path is sanitized by the pure heated water. During this cycle, as with the prior cycle, it is still possible to pass the heated, pure water through one or more of the dialysis machines to sanitize those dialysis machines in the manner described and with the signal to assert the personnel that the dialysis machines can be attached to the connections  78  during this cycle.  
     Reverse Osmosis Heat Sanitization Cycle  
      Turning now to  FIG. 5 , there is shown a reverse osmosis heat sanitization cycle of the present invention. This further cycle can be carried out, whether initiated manually or automatically, by passing the heated, pure water along a flow path that is only through the reverse osmosis units  46 ,  48 . Again the cycle is carried out by closing the valve  28 , thereby shutting off the supply of water from the inlet  10 . Valve  90  is opened so that the water can exit the storage tank  86  and, again, that water is pressurized by the heater pump  30  and the pressurized water passes through the heater  32  where it is heated to the desired sanitization temperature and at the maximum rate.  
      Continuing the cycle, the heated, pure water is carried by conduit  34  through open valve  36 , valve  92  being closed, such that the water passes along conduit  38  to tee  44  where the water can then pass though both of the inlet conduits  40  and  42  since both valves  50  and  52  are open so that the heated, pure water can enter and continue through both of the reverse osmosis units  46 ,  48  to heat sanitize those units and the water can continue through the outlet conduits  54 ,  56 . With this cycle, however, the valves  74  and  76  are closed and valves  94  and  96  are opened so that the water can continue through the conduits  98 ,  100  and return to the storage tank  86 . As a further path of the water during this cycle, the water that is normally may be drained through drain  70  continues to circulate in conduit  102  to the storage tank  86  for both of the reverse osmosis units  46 ,  48 .  
      Accordingly, as can now be seen, the control system  82  can take the reverse osmosis sanitizing system through various cycles in carrying out the sanitization of differing flow paths in the reverse osmosis system and thus, the user has the flexibility to select a particular flow path, whether in sanitizing the reverse osmosis units, the loop wherein the dialysis machines are fluidly attached or the like. The cycles can each be selected by the user or can be triggered automatically by the control system  82 . In each case, the pure water, that has passed through a reverse osmosis unit and has been accumulated in the storage tank  86 , is, during the particular sanitization cycle, pressurized and pumped through the particular selected flow path in the reverse osmosis system.  
      After each of the above described sanitization cycles, there is a “cool down” cycle that allows the reverse osmosis system to cool down to its normal operating temperatures and the cool down cycles use the lower temperature water that is supplied via the inlet of the reverse osmosis system and which is at the operating temperature of the system. The “cool down” cycles will, therefore be hereafter described.  
     Loop Cool Down Cycle  
      Turning, therefore, to  FIG. 6 , there is shown a schematic view of the loop cool down cycle that is used with the present invention. With this cycle, valve  28  is now opened and valve  90  closed thereby shutting off the water from the storage tank  86  and opening the system to the flow of water from the inlet  10  and which passes through the water pretreatment portion of the reverse osmosis system, that is, the water passes through at least one, preferably two, of the carbon filters  24  and the water softener  26 . That cooler water, normally at about 00 degrees C., then passes through the heater pump  30  that has been inactivated and through the heater  32  which has also been inactivated.  
      Continuing the cycle, the water is carried by conduit  34  through open valve  36 , valve  92  being closed, such that the water can continue along conduit  38  to tee  44  and into the inlet conduit  40  to enter and pass through the reverse osmosis unit  46 . As noted, at tee  44 , the water can pass through either or both of the inlet conduits  40 ,  42  depending on the position of the valves  50 ,  52 . Thus, depending on whether only one or both of the reverse osmosis units  4 ,  46  are to be cooled down, the user can select one or both of the valves  50 ,  52 .  
      Taking, again, the description of the reverse osmosis unit  44 , cooler water can pass through the membrane vessels  60 ,  62 ,  64  and deliver the water to the outlet conduit  54 . Thereafter, since valve  76  is open and valve  94  is closed, the cooler water can pass through the dialysis conduit  72 , past the connections  78  and continue through the open valve  88  (valve  80  is closed) to enter the storage tank  86 . The cooler water thereby cools any remaining heated water remaining in the storage tank  86  after a sanitization cycle so that the water in the storage tank  86  can be reduced to a temperature where it can be discharged safely through the open valve  102  via a drain  104 . As an example, normally at the initiation of the cool down cycle, the storage tank  86  may be three quarters filled with water at a temperature of about 65 degrees C. and the cooler water is introduced into the storage tank  86  at about 25 degrees C. such that the cooler water reduces the temperature of the water in the storage tank  86  to allow that water to be safely drained into a commercial municipal drainage system.  
      Again the flow of the cooler pure water is controlled by the control system  82  for a sufficient period of time that the various flow paths are cooled by the cooler pure water.  
      As described, this cycle circulates the cooler water through a selected portion of the flow path or flow paths of the overall reverse osmosis system and, as with the sanitization cycles, the particular flow path can be selected by the user and entered by means of the input  84  to the control system  82  to control the opening and closing of the various valves to carry out the selective cycle for cooling of the particular conduits and components in the selected flow path. Thus, as will be seen with the input  84  to control system  82 , the user can select one of the flow paths individually or all of the flow paths simultaneously for circulation of the cooler water by means of the control system  82  that operated the particular valves and controls the flow paths of the water in accordance with the user&#39;s input. Accordingly, as now described, this cycle circulates the cooler water from the inlet  10  through at least one of the reverse osmosis units and also through the loop where the dialysis machines are connected.  
     Reverse Osmosis and Loop Cool Down Cycle  
      Turning now to Fig,  7  there is shown a schematic view of the reverse osmosis and loop cool down cycle. With this cool down cycle, the reverse osmosis units and the loop having the connections  78  to the dialysis machines are cooled down. Again, as with the prior cool down cycle, valve  28  is opened and the valve  90  closed thereby allowing the cooler water to enter the reverse osmosis system from the inlet  10 .  
      Continuing the cycle, the cooler water is carried by conduit  34 , through open valve  36 , valve  92  being closed, such that the water passes through conduit  38  to tee  44  where the water can then pass though both of the inlet conduits  40  and  42  since both valves  50  and  52  are open so that the cooler water can enter and continue through both of the reverse osmosis units  46 ,  48  to cool those units. The cooler water can continue through the outlet conduits  54 ,  56 , through now opened valves  74  and  76  to enter the dialysis conduit  72  where the cooler water continues through that conduit and returns to the storage tank  86  through the open valve  88 , valve being  80  closed.  
      As such, the cooler water has, during that cycle, passed through the dialysis conduit  72  as well as both of the reverse osmosis units  46 ,  48  to cool the various conduits and components of the reverse osmosis system. Again, the flow of the cooler water is controlled by the control system  82  for a sufficient period of time that the flow path is cooled by the pure heated water and the admission of the cooler water into the storage tank  86  serves to cool the water in the storage tank  86  down to a temperature where it can be safely discharged via drain  104  into a municipal waste system.  
     Reverse Osmosis Cool Down Cycle  
      Turning finally to  FIG. 8 , there is show a schematic view of a reverse osmosis cool down cycle in accordance with the present invention. Again, this cycle is carried out by opening the valve  28  and closing the valve  90  thereby admitting the cooler water to the inlet  10  to the reverse osmosis system. The cooler water thereafter passes through inactive heater pump  30  and inactive heater  32  to conduit  34  and then through open valve  36 , valve  92  being closed, such that the water passes along conduit  38  to tee  44  where the water can then pass though both of the inlet conduits  40  and  42  since both valves  50  and  52  are open so that the cooler water can enter and continue through both of the reverse osmosis units  46 ,  48  to cool the conduits and components within those units and the water can continue through the outlet conduits  54 ,  56 . With this cycle, however, the valves  74 ,  76  are closed and valves  94 ,  96  are opened so that the water can continue through the conduits  98 ,  100  and return to the storage tank  86 . As a further path of the water during this cycle, the water that normally may be drained through drain  70  continues to circulate in conduit  102  to the storage tank  86  for both of the reverse osmosis units  46  and  48 .  
      Accordingly, as can now be seen, the control system  82  can take the reverse osmosis sanitizing system through various cool down cycles in carrying out the cool down of differing flow paths in the reverse osmosis system subsequent to a sanitization cycle and thus, the user has the flexibility to select a particular flow path, whether in cooling the reverse osmosis units, the loop wherein the dialysis machines are fluidly attached or the like. The cool down cycles can each be selected by the user or can be triggered automatically by the control system  82 . In each cycle, however, by the use of the cooler water, the ultimate water that is discharged into a municipal sanitation system is at an acceptable temperature for such discharge.  
      Those skilled in the art will readily recognize numerous adaptations and modifications which can be made to the sanitization system for a reverse osmosis system of the present invention which will result in an improved sanitization thereof, yet all of which will fall within the scope and spirit of the present invention as defined in the following claims. Accordingly, the invention is to be limited only by the following claims and their equivalents.