Abstract:
A water filtration system includes a filter for receiving water to be filtered and having an output. A water storage vessel is connected to receive water from the filter output; and water is removed from the storage vessel and supplied back to the input of the filter, whereupon filtered water to be utilized is obtained solely from the output of the filter.

Description:
BACKGROUND 
   The present invention relates to water filtration systems for filtering water from the source of water prior to delivering that water for utilization. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram of an embodiment of the invention; 
       FIG. 2A  is a block diagram of another embodiment of the invention; 
       FIG. 2B  is a block diagram of a variation of the embodiment of  FIG. 2A ; 
       FIG. 3  is a block diagram incorporating the embodiment of  FIG. 1  in a Reverse Osmosis Filtration System utilizing an automatic shut-off valve as a control element; 
       FIG. 4  is a block diagram incorporating the embodiment of  FIG. 1  in a Reverse Osmosis Filtration System utilizing a differential pressure switch as a control element; 
       FIG. 5  is a block diagram incorporating the embodiment of  FIG. 1  in a Reverse Osmosis Filtration System with a permeate pump utilizing a differential pressure switch as a control element; and 
       FIG. 6  is a block diagram incorporating the embodiment of  FIG. 1  in a Reverse Osmosis Filtration System with a permeate pump utilizing an automatic shut-off valve as a control element. 
   

   DETAILED DESCRIPTION 
   Reference now should be made to the drawings in which the same reference numbers are used in the various figures to designate the same or similar components.  FIG. 1  is a water filter system where water from a suitable source is applied through an input pipe at 9 to a control valve  11 . The valve  11  either may be manually operated or electrically operated, depending upon the particular environment in which the system is used. In the embodiment of  FIG. 1 , the valve  11  functions to supply water to a filter  18  when the valve is open. 
   The source of water supplied to the input  9  typically is obtained from a municipal water source, a well, or a cistern. The particular origin of the water supplied to the input  9  is not important; and it can be obtained from any suitable conventional source. 
   As shown in  FIG. 1 , the water passing through the filter  18  is supplied to one or the other of two paths. One of these paths is through an on/off water utilization valve  26  coupled to an output  28 . The output  28  is supplied to any desired utilization system, such as a drinking water tap or the like. This supply occurs when the valve  26  is open. 
   When the valve  26  is closed, however, the output flow from the filter  18 , as supplied by the input pipe  9 , passes through a check valve  20  to the input of a storage vessel  22 . In the embodiment shown in  FIG. 1 , the storage vessel is indicated as a captive air storage vessel of the type which uses an air pressure bladder tank to receive water from a source (in this case, the output of the filter  18  through the check valve  20 ) until a predetermined pressure is reached, at which time water flow into the pressure vessel is terminated by any suitable conventional means. 
   As is apparent from the description provided thus far, storage of the water in the storage vessel  22  is effected through a first filtration of that water through the filter  18 ; so long as the valve  11  is opened. When the valve  11  is closed (typically after the storage vessel desired pressure is reached), the system remains in a static condition of operation as long as the output valve  26  also is closed. Opening of the output valve  26  at some subsequent time, however, then allows the water in the pressure storage vessel  22  to be supplied through another check valve  24  back to the input of the filter  18 . The check valve  20  closes to prevent flow from the storage vessel  22  back into the output side of the filter  18 . 
   The water flow from the storage vessel  22  through the check valve  24  and the filter  18  then passes outwardly through the open output valve  26  to the utilization output at 28. It is to be noted that all of the water supplied out of the storage vessel is filtered by the filter  18  a second time, providing a dual pass of water through the filter  18 . The first pass through the filter  18  is from the output of the input valve  11 , which supplies the water to the storage vessel  22  initially. The second passage of water through the filter  18  is whenever the storage vessel  22  supplies that water through the check valve  24  for utilization at 28, when the valve  26  is opened. 
   By providing this second filtration of the water supplied from the storage vessel  22 , any stagnancy or contamination of the water which may occur in the storage vessel  22  is filtered by the unidirectional flow of water through the filter  18  prior to supplying that water to the output  28 . The system is a very simple system, not requiring any recirculating pump or similar provisions to ensure that the water supplied at the output  28  always is filtered. 
   Reference now should be made to  FIG. 2A , which is a modification of the system shown in  FIG. 1  and which includes additional components. In the system of  FIG. 2A , the water input at 9 is obtained in the same manner, from the same types of sources described above in conjunction with  FIG. 1 . The system shown in  FIG. 2A  is substantially identical to the one of  FIG. 1 , and operates in the same manner as described above in conjunction with  FIG. 1 . In the system of  FIG. 2A , however, the filter  18  of  FIG. 1  has been shown as being replaced by three different stages, including an ultraviolet or U.V. sterilizer  21  of conventional configuration for sterilizing the water prior to applying it to the input of the carbon block filter  23 . The output of the filter  23  then is supplied through a device  25  for adding desired additives to the water, such as calcium (or other desired additives, depending upon the ultimate use of the water produced b the system). In all other respects, the system shown in  FIG. 2A  operates in the same manner as the system shown in  FIG. 1 , with the filter  18  being replaced with the combination of the U.V. sterilization stage  21 , carbon filter  23 , and mineral additive stage  25 . 
     FIG. 2B  is a variation of the system shown in  FIG. 2A , and again, operates basically in the same manner as described above in conjunction with the system shown in  FIG. 1 . In  FIG. 2B , however, the filter  18  of  FIG. 1  has been replaced with a U.V. sterilization stage  21 , similar to the one shown in  FIG. 2A . The output of this stage then is supplied through a carbon filter  27 , which in turn has its output connected to the input of an ion exchange stage  29 . Again, the three-stage filtering component comprising the stages  21 ,  27  and  29  is substituted for and replaces the filter  18  of  FIG. 1 . 
   Reference now should be made to  FIG. 3 , which incorporates the system shown in  FIG. 1  in a Reverse Osmosis (RO) system. In the system of  FIG. 3 , water input at 10 is obtained in the same manner, from the same types of sources described above in conjunction with  FIG. 1 . This water input is shown as supplied through an automatic shut-off valve  34  to the input of a reverse osmosis filter  14 . 
   After passing from the output of the reverse osmosis filter  14 , the water is then supplied through a check valve  32 , and the through the automatic shut-off valve  34  to the input of the pressure storage vessel  24  (through the filter  18 ) in the same manner described above in conjunction with  FIG. 1 , whenever the output valve  26  is closed. Whenever water is provided from the storage vessel  22  through the check valve  24  to the input of the filter  18 , it is blocked by the check valve  32  from passage into the reverse osmosis filter  14 . Control of the water flow into the reverse osmosis filter  14  of  FIG. 2 , however, is automatically effected by means of the automatic shut-off valve  34 . Waste concentrate from the reverse osmosis filter  14  is supplied through a conventional flow restrictor  30 . In all other respects, however, the operation of the system of  FIG. 2  is the same as the one described above in conjunction with  FIG. 1 . 
   Reference now should be made to  FIG. 4 , which also incorporates the system shown in  FIG. 1  in another configuration of a reverse osmosis system. In the system of  FIG. 4 , the water input at 10 is obtained in the same manner, from the same types of sources described above in conjunction with  FIG. 1 . This water is shown as supplied through an electrical control valve  12  and through a pressure boosting pump  13  to the input of the reverse osmosis filter  14 . 
   In  FIG. 4 , the valve  12  is an electrically controlled valve which is controlled by a differential pressure switch  36  located near the input of the filter  18 . The switch  36  monitors the pressure of the storage vessel  22 . The differential pressure switch  36  also controls the operation of the pressure boosting pump  13 . The pump  13  may not always be needed; and it can be eliminated if it is not used. 
   After passing from the output of the reverse osmosis filter  14 , the water is supplied through the check valve  32 , and then through the filter  18  to the input of the pressure storage vessel  22  in the same manner described above in conjunction with  FIG. 1 , whenever the output valve  26  is closed. Again, whenever water is provided from the storage vessel  22  through the check valve  24  to the input of the filter, it is blocked by the check valve  32  from passage back into the reverse osmosis filter  14 . Control of water flow into the input of the reverse osmosis filter  14  of  FIG. 4 , however, automatically is effected by means of the electric valve  12 . In all other respects, the operation of the system of FIG.  4  is the same as the one described above in conjunction with  FIG. 1 . 
   Reference now should be made to  FIG. 5 , which is a modification of the system shown in  FIG. 4 . In the system of  FIG. 5 , water input at 10 is obtained in the same manner and from the same types of sources as described above in conjunction with  FIGS. 1 and 4 . The water is shown as supplied through an electric valve  12  and through an optional pressure boosting pump  13  to the input of the reverse osmosis filter  14 . As in the system shown in  FIG. 4 , the valve  12  is controlled by a differential pressure switch  36  located near the input of the filter  18  to monitor the pressure of the storage vessel  22 . As mentioned in conjunction with the system of  FIG. 4 , the pressure boosting pump  13  may not always be needed; and it can be eliminated if it is not used. 
   After passing from the output of the reverse osmosis filter  14 , the water is supplied through a permeate pump  38  to the input of the floater  18 , and ultimately, to the pressure storage vessel  22  in the same manner described above in conjunction with  FIG. 1 . This occurs whenever the output valve  26  is closed. Whenever water is provided from the storage vessel  22  through the check valve  24  to the input of the filter  18 , it is blocked by the permeate pump  38  from passage into the reverse osmosis filter  14 . The manner of operation of such a permeate pump is standard and well known; so that no details of that operation are considered necessary here. Again, as in the case of the system of  FIG. 4 , control of water into the reverse osmosis filter  14  of  FIG. 5  is automatically effected by means of the electric valve  12 . 
   Reference now should be made to  FIG. 6 , which is a further variation of the system employing a reverse osmosis filter  14 , and incorporating some of the features of  FIGS. 3 and 5 . In the system of  FIG. 6 , the water input at 10 is obtained in the same manner, from the same types of sources described above in conjunction with  FIGS. 1 through 5 . This water is shown as supplied through an automatic shut-off valve  34  coupled to the input of the reverse osmosis filter  14 . 
   After the water passes from the output of the reverse osmosis filter  14 , it is supplied through the automatic shut-off valve  34  and then through the permeate pump  38  to the input of the pressure storage vessel  22 , through the filter  18 , in the same manner described above in conjunction with  FIG. 1 . This occurs whenever the output valve  26  is closed. Whenever water is provided from the storage vessel  22  through the check valve  34  to the input of the filter  18 , it is blocked by the permeate pump  38  from passage into the reverse osmosis filter  14 . The operation of the system shown in  FIG. 6  essentially is a combination of the operation of the features of the system shown in  FIG. 3  using an automatic shut-off valve  34 , and the system of  FIG. 5  using a permeate pump  38 . Again, control of the water flow into the reverse osmosis filter  14  of  FIG. 6  automatically is effected by means of the shut-off valve  34 . In all other respects, the operation of the system of  FIG. 6  is one which incorporates the operation of the basic double pass filter system of  FIG. 1 . 
   It should be noted that the double filtration of water effected by the filter  18 , utilizing the system concept shown in  FIGS. 1 ,  2  and  3  in particular, takes place whether the water input in the first instance is from another filter, such as the reverse osmosis filter  14 , or is from an original un-filtered water source. If a filter such as the reverse osmosis filter  14  is not needed, it simply is eliminated; and the output of the valve  11  or  12  may be connected through an additional check-valve  16 , or the water supply may be supplied through such an additional check-valve  16  without incorporating either of the valves  11  or  12 , to supply water to the input of the filter  18  in the manner described above in conjunction with  FIG. 1 . For maximum purity of the water, however, it is desirable to have an input filter stage such as the reverse osmosis filter  14  shown in FIGS.  3 , 4 , 5  and  6 . It further should be noted, however, that even if two filters (such as the filter  14  and filter  18 ) are employed, the reverse osmosis filter  14  may be replaced by some other suitable type of input stage filter, if the particular environment in which the system is used does not require a reverse osmosis filter  14 , and another type of filter would be suitable. 
   An application where the various embodiments of the invention which have been described above are particularly useful is in conjunction with water systems which are de-ionization systems. In such systems, there is an ion exchange which takes place in the water stored in the storage vessel  22 . When such water is stored over a period of time, however, ion exchange resins in the water contaminate the water; but the second pass of the stored water through the check-valve  24  and through the filter  18  (or filter strings  21 , 23 , 25  of  FIG. 2A  or  21 , 27 , 29  of  FIG. 2B ) purify the stored water, removing the effects of stagnation from it prior to the water being supplied through the valve  26  to the output  28 . In addition, the overall system is very compact, employing a low component count, and in the most basic form described above, it does not require any electrical connections. 
   The foregoing description of the preferred embodiments of the invention is to be considered as illustrative, and not as limiting. Various changes and modifications will occur to those skilled in the art for performing substantially the same function, in substantially the same way, to achieve substantially the same result without departing from the true scope of the invention as defined in the appended claims.