Abstract:
Reverse osmosis filtration systems that are self contained and easily converted from above the counter use to below the counter use. The systems feature a simple construction, including a two piece manifold assembly to which filters, including a reverse osmosis filter, a product water storage tank and a control valve connect, all without separate fasteners. The manifold assembly provides all water connections within the system, and includes connections to connect to a water supply, a drain, two dispensers and to an auxiliary water storage tank. The system pressurizes squeeze water for product water dispensing, providing maximum efficiency, maximum storage capacity for a given tank size and maximum pressure for dispensing product water. Various embodiments are disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/711,837 filed Aug. 26, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to the field of reverse osmosis filtration systems.  
         [0004]     2. Prior Art  
         [0005]     Reverse osmosis water filtration systems pressurize one side of an appropriate membrane with source water, causing the water to slowly pass through the membrane, leaving impurities therein on the source water side of the membrane for flushing away by controlled flow of excess source water past the membrane. The filtered or product water passing through the membrane is accumulated in a storage tank having a flexible bladder separating the storage tank into a product water storage area and a squeeze water area. Normally when the product water storage tank area defined by the bladder is filled, the bladder lies flat against the tank wall. Now when the product water is to be dispensed, squeeze water is coupled to the region between the bladder and the tank wall. However, because the bladder is flat against the tank wall, it takes a moment for the squeeze water to seep between the bladder and the tank wall. Therefore there is an initial hesitation in squeeze water flow, and accordingly in product water pressurization, providing an undesired hesitation and uncertainty in the initial product water dispensing.  
         [0006]     In addition to the storage tank and the reverse osmosis membrane, other components are also required, such as conventional source water filters and activated charcoal filters to remove chlorine from the water prior to the reverse osmosis membrane, a control valve to control operation of the system, and plumbing to connect the various elements and to provide a source water inlet, one or more product water outlets, and a drain outlet. While these components can be coupled together with conventional hose fittings and the like, such an arrangement tends to be a bit kludgy and labor intensive to assemble and service, and tend to be larger than necessary.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIGS. 1 through 4  present a first end view, a first side view, a second side view and a bottom view, respectively of one embodiment of the present invention.  
         [0008]      FIG. 5  is a cross section of a tank assembly in accordance with a preferred embodiment of the present invention.  
         [0009]      FIG. 6  is a view looking directly into the upper shell  22  of the embodiment of  FIG. 5   
         [0010]      FIG. 7  is a cross section similar to that of  FIG. 5 , but with the bladder shown in the right side of the Figure.  
         [0011]      FIG. 8  is a perspective view of the final tank assembly of the preferred embodiment.  
         [0012]      FIG. 9  is a perspective view of one of the filter cartridges.  
         [0013]      FIGS. 10, 11  and  12  are a top perspective view, a top face view and a bottom view, respectively, of the lower manifold plate.  
         [0014]      FIGS. 13 and 14  are bottom and top face views, respectively, of the upper manifold plate.  
         [0015]      FIG. 15  is a perspective view of support members for further support of the product water storage tank.  
         [0016]      FIGS. 16 through 20  and  24  illustrate the construction of a typical filter cartridge.  
         [0017]      FIGS. 21 and 22  illustrate the mounting of the control valve.  
         [0018]      FIG. 23  is a cross section illustrating the mounting of the water storage tank to the rest of the assembly.  
         [0019]      FIG. 25  is a diagram of an exemplary system in accordance with the present invention.  
         [0020]      FIGS. 26 through 29  illustrate the various stages of operation of the control valve used in the preferred embodiment of the present invention.  
         [0021]      FIGS. 30 and 31  are diagrams illustrating the convertability of the systems of the present invention from above the counter use to below the counter installations.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     The present invention comprises integrated reverse osmosis filtration systems of a compact design having a minimum number of parts and easily connected and serviced, and suitable for use above or below a counter. An embodiment of the present invention may be seen in  FIGS. 1 through 4 .  FIG. 1  is a first end view of one embodiment reverse osmosis filtration system of the present invention,  FIG. 2  is a first side view,  FIG. 3  is a second side view, and  FIG. 4  is a bottom view. In  FIG. 1 , the main components that are visible are the storage tank for the storage of product water, generally indicated by the numeral  20 , and a top plate assembly, generally indicated by the numeral  48 . As shall subsequently be seen, the top plate assembly is a manifold assembly providing all water interconnections required within the system. In  FIGS. 2 and 3 , also visible are cartridges  52 ,  54  and  56  that contain a conventional filter, a reverse osmosis filtration membrane and an activated charcoal filter, respectively. Visible in  FIG. 2  are two connections  58  to the outside world, and in  FIG. 3 , an additional four connections  60  to the outside world are shown. Four of these connections provide connections for the source water input, the membrane flush water and squeeze water output to drain, and two product water outputs to accommodate simultaneous connection to a dispensing tap and to an icemaker. Obviously, if the system is only used to provide tap water, the icemaker output is merely capped off. The additional two connections are a product water connection for connecting to an extra storage tank, if used, and a squeeze water connection for such an extra tank. These, too, would be capped off unless such an extra tank was in fact used. These connections are subsequently described in greater detail.  
         [0023]     Also visible in  FIGS. 2 and 3  is a control valve  62  that provides hydraulic control for the entire system. The control valve used in the preferred embodiment is in accordance with U.S. Pat. No. 6,110,360, the disclosure of which is hereby incorporated by reference. However, valves of other designs could be adapted for use with the present invention as desired.  
         [0024]     As may be seen in  FIG. 5 , the storage tanks  20  of the preferred embodiment are manufactured from upper and lower injection molded shells  22  and  24 , with the lower shell  24  having a hollow circular base  26  for support of the finished tank  20  on a flat surface.  FIG. 5 , being a cross-section of the tank, shows the ribs or protrusions  28  and  30  in the upper and lower tank shells  22  and  24 , respectively. These ribs are rib-like protrusions integrally molded on the inside surface of the tank shells, the function of which shall be subsequently described.  FIG. 6  is a view looking into the upper shell  22  providing a face view of the ribs.  
         [0025]     Also shown in  FIG. 5  is a top member  32  providing a central opening  34  for product water into and out of a bladder that will be placed within the tank, and a plurality of peripheral openings  36  for squeeze water to selectively pressurize the product water for dispensing purposes. In the preferred embodiment, the two tank shells  22  and  24  are spin welded together to provide a strong and permanent joining of the two members to define a substantially spherical inner surface interrupted primarily by the ribs just described.  
         [0026]     Now referring to  FIG. 7 , the left side of the Figure shows the same cross-section as  FIG. 5 , with the right side of the Figure showing the cross-section of the tank after bladder  38  has been installed. Bladder  38  is preferably a spherical blow molded bladder of any flexible material conventionally used for reverse osmosis filtration storage tank bladders, and has a neck that fits over downward protrusion  40  of member  32  and is sealed with respect thereto. As may be seen in the lower part of  FIG. 7 , ribs  30  locally hold the bladder away from the wall of shell  24 , with ribs  28  shown in  FIG. 5  doing the same with respect to shell  22  at other positions around the inner periphery of the shell. In that regard, the relative angular orientation of the two shells  22  and  24  is not relevant, and need not be controlled. The ribs provide a squeeze water flow path around a filled bladder, eliminating any delay or hesitation in fully pressurizing the bladder for pressurized product water dispensing upon opening of a valve on a product water outlet.  
         [0027]     A perspective view of the finished assembly of the preferred embodiment may be seen in  FIG. 8 . As shown therein, in the preferred embodiment the top  42  of the upper shell  22  has a form of bayonet-type connector  44  which will fasten the top  42  of the tank to the rest of the reverse osmosis filtration system assembly, with an O-ring in O-ring groove  46  (see  FIGS. 1 and 2 ) sealing the product water connection and an O-ring fitting within the inner periphery of the top  42  sealing against that inner periphery to prevent leakage against squeeze water, particularly when pressurized. This assembly will be described in greater detail later herein.  
         [0028]     In operation, during filtration, the squeeze water region between the bladder  38  and the inner periphery of the tank  20  is vented to drain so that the product water passing through the reverse osmosis membrane will accumulate in the interior of the bladder. Thus the bladder will essentially fill with product water, displacing most of the squeeze water out to drain. However the ribs  28  and  30  on the inner periphery of the tank hold the bladder locally away from the inner wall of the tank to leave flow passages through ports  36  to these regions around the ribs. Consequently when the bladder is full and the system shuts off, these flow passages at each side of the ribs will remain. Now when product water is called for, such as by the opening of a faucet or the turning on of an ice maker valve, and the system pressurizes the squeeze water, the squeeze water is free to flow into the region between the bladder  38  and the inner periphery of the tank, pressurizing the product water substantially immediately for dispensing purposes. Consequently, the tank of the present invention is easily injected molded and spin welded and has the further advantage of eliminating the hesitation and uncertainty in the initial dispensing of product water from a full storage tank.  
         [0029]     In the preferred embodiment, ribs are disposed on the interior surface of the tank to define flow paths for the initial inflow of squeeze water. Alternatively, similar depressions could be used in the tank wall, but are not preferred, as they weaken the tank, requiring a somewhat thicker average wall thickness for the tank, adding expense. As further alternatives, however, the ribs do not need to run throughout the inner surfaces of the tank, or be circumferentially oriented, but at least should emanate from the squeeze water connection to the tank. Each “rib” also could be in the form of two raised areas adjacent each other, thereby defining another squeeze water flow path between the raised areas. Similarly, the tank shells may define an interior other than spherical, and/or may be assembled other than by spin welding, though spin welding is preferred as providing a very inexpensive manufacturing technique that provides a weld strength substantially as strong as the molded material itself.  
         [0030]     Now referring to  FIG. 9 , a perspective view of the filter cartridges  52  and  56  may be seen. These cartridges are comprised of a molded body  66  with a molded top cap  68  having an upward projecting bayonet-type mechanical connector. In the final assembly, water flow into and out of the cartridges is provided through opening  70  and through annular area  72 , with the filter cartridges being sealed with respect to the final assembly by O-rings in O-ring grooves  74  and  76 . It will be noted that the bayonet connector on member  68 , preferably spin welded to the body  66 , is a six element bayonet connector rather than a typical two element connector, which provides for seating and locking of the cartridges in the final assembly with only a minor rotation of the canisters.  
         [0031]     The top plate assembly of  FIGS. 1 through 4 , as stated before, provides all of the required manifolding for interconnection of the water flow paths within the system. This top plate assembly  48  is comprised of two manifold plates, which in the preferred embodiment are hot-plate welded together. The lower manifold plate, generally indicated by the numeral  78 , may be seen in  FIG. 10 , with a face view of the top of that plate being shown in  FIG. 11 .  FIG. 10  shows one of the receptacles  80  for the filter cartridge  56  ( FIG. 3 ). Also visible are the mating connectors  82  for the bayonet connector on the filter cartridges and the mating bayonet connector  84  for the product water storage tank  20  ( FIGS. 1 through 3 ). Finally, also visible in  FIG. 10  are four of the six external connections  60  ( FIG. 3 ) hereinbefore described.  FIG. 12  is a bottom view of the lower manifold plate of  FIGS. 10 and 11  showing, in essence, the receptacle for the filter cartridges and for connection to the water storage tank, as well as fluid connections  86  to the control valve  62  ( FIGS. 2 and 3 ) hereinbefore described.  
         [0032]     The bottom of the upper manifold plate  88  of the manifold assembly may be seen in  FIG. 13 , with the top of the upper manifold plate  88  being shown in  FIG. 14 . As may be seen in  FIG. 13 , the flow passages in the lower surface of the upper manifold plate  88  essentially replicate the flow passages defined in the top of the lower manifolding plate  78  shown in  FIG. 10 . Accordingly, when the two plates are hot welded together, the assembly provides all of the manifolding required for the system.  
         [0033]     Once the subassemblies are completed, the assembly of the reverse osmosis water filtration unit is simply a matter of mounting the control valve  62  ( FIGS. 2 and 3 ) and attaching the water tank  20  and the filter canisters  52 ,  54  and  56  to the top plate assembly using the bayonet connectors. To provide extra stability for the storage tank  20 , three support members  90  shown in  FIG. 15  are used to provide further support for the tank, the support members having an upper tab  92  for hooking through openings  94  ( FIG. 12 ) in the lower manifold plate  78  and also snapping under a lip provided in the lower tank shell of tank  20 , as may be seen in  FIGS. 1 through 4 . The lower circular base  26  on the tank  20  provides a stand for the entire assembly, with the six water connections hereinbefore referred to readily accommodating the attachment of a local or remote faucet, as well as supply and drain lines, so as to be readily used as an above-counter unit or as a below-counter unit, as desired.  
         [0034]      FIGS. 16 through 20  and  24  show filter enclosure details, most of which are common to filters  52 ,  54  and  56  ( FIGS. 2 and 3 ). Each filter has an injection molded body  66  with a cap  68  spin welded thereto. Entrapped within this assembly is a spacer member  104  (see also  FIG. 24 ) that centers the upper end of filter element  106  while providing a flow path between fingers  108  from port  110  to region  112  around the periphery of the filter element  106 . The spacer member  104  also defines a central port in fluid communication with the inner diameter of the filter element  106  through a protrusion  114 , with O-rings  116  and  118  sitting against the inner diameters of protrusions  110  and  112  in the lower manifold plate  78  (see  FIG. 12 ). The bottom end of filter element  106  is centered by protrusion  118  at the bottom center of body  66 . Thus for assembly purposes, the filter element  106  is dropped in position, spacer member  104  placed thereover, then cap member  68  placed over that assembly and spin welded to the body  66  to complete the assembly, except for the O-rings  116  and  118 .  
         [0035]     As may be seen in  FIG. 17 , the cap  68  has protrusions  120  thereon, in its preferred embodiment a total of six such protrusions, which together with inward projecting protrusions  122  on the lower manifold plate  78  (see  FIG. 12 ) form a bayonet type connector. This connector allows rotation in a first direction as if screwing the filter onto the lower manifold plate with conventional screw threads until the leading lip  124  on each of protrusions  120  slips past the upper end of the inward projections  122 , at which time the filter cartridge will lock in place in a sort of snap action caused by the combination of the absence of a further longitudinal motion of the filter and the elastic deflection of O-rings  116  and  118 . The use of four or more such projections allows at least four starting positions for the filters, and rapid locking in place with limited rotation of the filters.  
         [0036]     When the filters are rotated in the opposite direction, protrusions  120  will be rotated until they engage the lower surface of inward projections  122 , thereby forcing the filter downward with respect to the lower manifold plate  78 . In the preferred embodiment, the protrusions forming the bayonet connector are configured so that the screw type action of the bayonet connector pulling the filter cartridge into position with respect to the lower manifold plate  78  will begin before any forcible engagement of O-rings  116  and  118  with the circular protrusions on the lower manifold plate  78  begin. This allows the screw action to forcibly engage the O-rings, a far more convenient action than trying to simply force the filter longitudinally upward to engage the O-rings. Similarly, the bayonet connectors are configured so that on rotation to unscrew a filter from the lower manifold plate  78 , the bayonet connector will force a sufficient separation between the filter and the lower manifold plate  78  to forcibly disengage the O-rings  116  and  118  before reaching the end of the screw type action. This is illustrated generally with respect to  FIG. 18 , generally illustrating the beginning position of a filter for engagement purposes, or alternatively, the ending position of a filter after being disengaged,  FIG. 20  illustrating the relative position of the filter and the lower manifold plate  78  when the filter is in its mounted position. In  FIG. 20 , ports  77  appear small in the Figure, though are actually 4 arc segments providing a much larger flow area than is apparent from the Figure.  
         [0037]     The reverse osmosis filter cartridge  54  (see  FIGS. 2 and 3 ) has an identical bayonet type connection to the lower manifold plate  78  as just described. It differs, however, in that three concentric inlet ports are provided, one for a raw water inlet, one for product water outlet and the third for a waste water outlet. See for instance the connections on the lower manifold plate  78  shown in  FIG. 12 .  
         [0038]     Now referring to  FIGS. 21 and 22 , the mounting in the control valve  62  of the preferred embodiment may be seen. In these Figures, only the body of control valve  62  is shown, though the complete control valve is shown in  FIGS. 2 and 3 , and is in accordance with U.S. Pat. No. 6,110,360 as previously mentioned. The body of control valve  62  has four ports thereon extending away from the body, two of which ports  126  and  128  may be seen in  FIG. 21  and one of which port  126  may be seen in  FIG. 22 . The port shown on  FIG. 2  is a restricted port for waste water, the other three ports having a much larger opening for substantially unrestricted flow therethrough. The four ports have O-rings  130  thereon which seal between the ports in the underside of the lower manifold plate  78 , as illustrated in  FIG. 22 . The body of the control valve has two projections  132  integral therewith which snap through cooperatively disposed opening  134  in the lower manifold plate  78  to retain the control valve in the assembly. Accordingly assembly of the control valve to the next assembly is simply a matter of placing the O-rings in position and snapping the valve into position, not requiring the use of any tools, etc. In the event removal of the control valve  62  is ever required, openings  134  are provided in the upper manifold plate  88  (see  FIGS. 13, 14  and  22 ), facilitating the use of a screwdriver or a pair of screwdrivers to release the control valve  62  from the assembly.  
         [0039]     Now referring to  FIG. 23 , details of the manner of attachment of the water storage tank  20  (see also  FIGS. 1 through 5 ) may be seen. The lower manifold plate  78  includes two inward projecting flanges  136  (see also  FIG. 12 ) in the form of approximately 90° arc segments around a center port  138  in the lower manifold plate  78 . The water storage tank has outward projecting flanges  44  (see also  FIG. 8 ) so that the water storage tank may be assembled to the rest of the assembly by simply placing the storage tank in position and rotating the same 90° with respect to the rest of the assembly.  
         [0040]     Pressed within the top of the storage tank  20  is an insert member  140  defining a central port aligned with port  138  in the lower manifold plate  78  and spaced apart ports  36  around the periphery thereof. Ports  36  provide communication for the squeeze water from manifold region  144  to the outside of the bladder in the water storage tank  20 , whereas the central port  138  is in communication with the manifold region  146  for the product water. Sealing of these ports is by O-rings  148  and  150 .  
         [0041]     Having now described the general construction of the present invention, the manifolding defined by the upper and lower manifold plates  88  and  78  may be traced with the aid of  FIGS. 2, 3 ,  10 ,  11  and  12 . For this purpose, two of the six ports for connection to the outside world are labeled  58   1  and  58   2  in  FIG. 2 , and the other four labeled  60   1  through  60   4  in  FIG. 3 . That labeling may be seen in  FIG. 12  and some of the labeling seen in  FIG. 10 . For clarity, connections to those ports shown in  FIG. 11  also have the same labeling, though it should be understood that as shown in  FIG. 11 , these connections, though in communication with the ports to the outside world, are actually fluid connections to the internal manifold defined by the upper and lower manifold plates. The raw water inlet port is port  58   1 , with the manifolding directing the raw water to filter  52  ( FIG. 2 ). After the water passes through the filter the manifolding directs the water to the outside of the RO filter element in filter  54 , with product water going to the outside periphery of the charcoal filter element in filter  56  and to the central port of the storage tank  20 . Also, after passing through the charcoal filter the product water is available on product water outlet ports  60   2  and  60   3 . In that regard, two such ports are provided in the preferred embodiment, one for connection to a dispenser and one for connection to an ice cube maker. Port  60   4  is also coupled to the center port on the storage tank  20  and is connectable to an auxiliary storage tank, if desired. In that regard, squeeze water for pressurizing the product water in the storage tank for dispensing purposes is also coupled to port  58 . 2  for coupling to the squeeze water connection of an auxiliary tank, if used. If not used, ports  58   2  and  60   4  are simply blocked off. Finally, port  60   1  is the wastewater outlet port.  
         [0042]     The control valve  62  responds to operating conditions to control the water filtering and dispensing processes. In particular, when not dispensing and when the storage tank  20  is not full of product water, the control valve couples the raw water inlet through the filter  52  to the reverse osmosis membrane in filter  54 , at the same time venting squeeze water and waste water to the waste water outlet. When the pressure in the product water storage tank increases, indicating that the tank is full, the wastewater will be shut off. When a valve coupled to one of the outlets  60   2  and  60   3  opens, the pressure drop will cause the control valve to couple the raw water inlet to the squeeze volume around the membrane in the product water storage tank to pressurize the same for dispensing through the respective outlet port. Consequently, the system is self-activating, shutting off all raw water flow once the product water storage tank  20  is full, thereby using no more water for operation of the system than necessary. Also the dispensing of product water by pressurizing the product water storage tank allows the system to be mounted on a counter with its own dispensing valve and decorative enclosure, or mounted below the counter to deliver product water to a remote faucet or ice cube maker on demand.  
         [0043]     A diagram of an overall system may be seen in  FIG. 25 . The filter  52 , preferably a combined fabric and carbon filter, is connected to a source of raw water  160 , preferably through a dedicated shutoff valve  162 . The outlet of filter  52  is coupled to the inlet of the reverse osmosis filter  54 , with the product water thereof being coupled to the inlet of carbon filter  56  and to a product water storage tank  20 . The waste water outlet for reverse osmosis filter  54  is coupled to port  1  of valve  62 . The squeeze water connection for the storage tank  20  is coupled to port  2  of valve  62 , with port  3  being coupled to a drain and port  4  being coupled to the product water output line prior to the dispenser (or ice cube maker or other product water utilization means) valve  164 .  
         [0044]      FIG. 25  does not include the additional product water and squeeze water connections for a remote storage tank, and for the purposes of this Figure, assumes that such connections are not available or have been sealed off. Also shown in this Figure are check valves  166  and  168  in the product water outlet of filters  54  and  56 , respectively. These check valves, not shown in the other Figures, are small check valves in the outlet ports of these filters, allowing one-way flow as shown in  FIG. 25 , but preventing flow in the opposite direction. Check valve  166  prevents pressurizing the inner diameter of the reverse osmosis filter element when the outer diameter is not pressurized.  
         [0045]     The four states of the control valve  62  are shown in  FIGS. 25 through 28 . The body assembly  170  of the control valve includes various O-rings for sealing against a two diameter piston  172 , which is free to slide back and forth within the body assembly  170  in response to various pressures thereon. The body assembly  170  includes a throttling screw  174  that can allow for restricted flow between ports  1  and  2  through passage  176  and the narrow annular passage around the throttling screw, depending on the position of the piston  172 .  
         [0046]      FIG. 26  shows the control valve with the piston  172  in an at rest position. This would represent the condition existing when no product water is being dispensed and the water storage tank  20  is full of product water. Product water pressure through port  4 , at or near raw water pressure and acting against the larger end of piston  172 , forces the piston  172  to the rightmost position against the waste water pressure in port  1 , also substantially equal to a raw water inlet pressure on line  160 . In this position, waste water flow through port  1  and passage  176  is blocked, squeeze water flow through port  2  is blocked and any flow to port  3 , the drain, is blocked. Thus all water flow is shut off.  
         [0047]     When a dispensing valve  164  is opened, pressure of the product water drops. Now the waste water pressure in line  1  is adequate to overcome the product water pressure on port  4 , causing the piston  172  to move to the leftmost position as shown in  FIG. 27 . In this position, port  1  of the valve is coupled to port  2 , coupling the waste water from the reverse osmosis filter  54  to the water storage tank  20  as squeeze water to pressurize the product water for dispensing. In this position, port  3  of the control valve  62  is blocked so that no water passes to drain. However, given a substantial product water flow to the dispenser or ice cube maker, the waste water flow past the outside of the reverse osmosis filter element in filter  54  is relatively fast, thereby acting to clean the reverse osmosis filter element by this high rate of flow. In that regard, the reverse osmosis filter  54  in the preferred embodiment is configured to provide a relatively high flow velocity of waste water past the raw water side of the filter element (i.e., configured for a small flow area) for good cleaning of the outer surface of the element.  
         [0048]     When dispensing stops, the pressure in the dispensing line will recover, increasing the pressure on the large end of piston  172  until the force caused by that pressure on the larger end of the piston overcomes the force of the waste water pressure on port  1  of the valve, forcing the piston  172  toward the right as shown in  FIG. 28 . When the right end of the piston seals with respect to the rightmost O-ring, waste water port  1  is sealed off from squeeze water port  2 , except for a small flow path around the throttling screw  174  to port  2 . Accordingly, once the piston  172  relatively rapidly moves to this position, the squeeze water flow rate grossly reduces so that the final recovery of product water pressure provided to port  4  slowly further increases. This slowly forces piston  172  toward the right until port  2  is coupled to port  3 , i.e., until squeeze water is coupled to drain. This is shown in  FIG. 29 . Coupling squeeze water to drain eliminates the pressure on the product water, though check valve  168  maintains the volume of water at the left end of piston  172  so that the piston cannot move toward the left again, in spite of the drop in product water pressure. Since pressure is always applied to the raw water side of the reverse osmosis filter  54 , filtering again begins with the product water produced being added to storage tank  20 , displacing the now unpressurized squeeze water through port  2  to port  3 , the drain port. At the same time, there is a low flow rate of waste water from port  1  past throttling screw  174  and through passage  176  to port  2 , and thus to port  3 , to drain. In a preferred embodiment, the flow rate of this waste water is set to approximately equal the filtration rate, that is, the rate at this product water is produced. Consequently, for each volume of product water produced, an approximately equal volume of waste water slowing flushing the reverse osmosis filter element is produced, and in addition, an additional equal volume of waste water is produced by the displacement of unpressurized squeeze water to drain. Consequently, in the present invention system approximately one third of the water used by the system is provided as product water, with the system maintaining the same efficiency whether the water storage tank  20  is nearly full or nearly empty. This is to be compared with captive air systems wherein the efficiency steadily decreases as more product water is produced. This is because of the increase in air pressure in the product water storage tank with an increase in the amount of product water stored, all while the waste water flow rate is constant, thereby continuously decreasing the efficiency of the system until the system is shut off. While the efficiency in terms of product water produced compared to total water used, in a preferred embodiment, is approximately one third or 33%, this could be varied by changing the throttling screw  174 , and may vary somewhat with raw water pressure if not regulated, though preferably is set to be at least 20%, and more preferably at least 25%. The high efficiency not only conserves water, very important in itself, but also reduces the demands on the filter on the raw water side of the reverse osmosis filter, thereby allowing the use of a smaller filter and/or longer durations between filter changes.  
         [0049]     When the product water storage tank  20  is filled the product water pressure will rise toward the pressure of the raw water on line  160 . When the product water pressure exceeds the pressure of the product water previously trapped in the line going to port  4  of the control valve, check valve  168  will open, allowing the pressure to increase on the left end of piston  172 , forcing the piston back to the position shown in  FIG. 26  to shut off all water flow until a dispenser or ice cube maker valve (or some other product water output valve) is again opened.  
         [0050]     Another aspect of the present invention is its adaptability for either above counter or under counter use, and its adaptability for a multitude of cosmetic embellishments. By way of example,  FIGS. 30 and 31  present artist renditions of exemplary enclosures for both above counter or under counter use, each having its own distinctive appearance even though all would house the same basic reverse osmosis water filtration chassis.  FIGS. 30   a  and  30   c  show the system of an embodiment of the present invention configured for above counter use, wherein a base  178 , a decorative enclosure  180  and a moveable back cover  182  house a system, with a top assembly  184  connecting to or sealing the various ports and providing a manually operable dispensing head  186 . The removable cover  182  provides access to the filters of the system when the same need to be changed. Water supply and drain lines  188  are provided out the back of the system for connection as required. The same system, however, may also be used under the counter by replacing the cover  184  with cover  190  and connecting the various lines as required, including a connection to an above the counter dispenser and/or ice cube maker or other device using the product water. In that regard, as used herein, the phrase “under the counter” is used in the general sense to mean remote from the product water dispensing valve manually operated or automatically operated by other devices.  
         [0051]      FIG. 31   a  through  FIG. 31   c  show an alternate housing configuration for the present invention. Here, a base  194 , decorative cover  196  and removable back cover  198  are provided. In this embodiment, various water inlet and outlets are connected internally to connections  200 , which in turn, may be connected and/or sealed as required for under the counter use. Alternatively, a dispensing head  202  may be connected thereto to, itself connecting to or sealing the appropriate connections on the system. In such a configuration, the raw water supply and connection to drain are brought out through the back of the system.  
         [0052]     The ability to convert the system of the present invention from an above the counter to a below the counter system is highly advantageous. In particular, below the counter systems typically have had a separate storage tank, and accordingly, do not facilitate use of the same on the countertop. On the other hand, for evaluation purposes, people may want to use the system on the countertop for a while before permanently installing the system below the counter with a hole through the counter for the dispenser, etc. The present invention allows the easy installation of the system on a counter top, and a minimal change of the system for installation of the same system below the counter, typically at a later date after the user of the system becomes comfortable with the system and committed to its continued use. Thus there is a great marketing advantage to being able to first install and use the system above the counter and then later use the same system with only a minor modification as a below the counter system by removing the dispensing head and making appropriate connections for under the counter use. This avoids having to install one system above the counter, and then later have to swap systems when a below the counter installation is desired.  
         [0053]     It should be noted that exemplary embodiments of the system of the present invention have been disclosed herein, though various sub-combinations of the system may also be advantageously used if desired. Thus while certain preferred embodiments of the present invention have been disclosed and described herein for purposes of illustration and not for purposes of limitation, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.