Fluid treatment system

1. A reverse osmosis system comprising:

a system control assembly including a housing, said control assembly defining an inlet for feed water to be treated and an output from which permeate is discharged;

a reverse osmosis membrane cartridge, external to and removably attached to said housing, said membrane cartridge adapted to receive feed water from said housing and to discharge permeate to said housing; and

a membrane flushing system located within said housing, said flushing system including a permeate accumulator located within said housing and having separate feed water and permeate storage chambers separated by an elastomeric member such that pressurization of said feed water chamber is operative to urge permeate from said permeate chamber under predetermined conditions, and a flush pilot valve assembly that initiates a flush cycle in response to sensing a predetermined permeate pressure in a permeate storage tank, and during said flush cycle said flush pilot valve assembly operative to disconnect feed water from said cartridge and supply permeate from said accumulator to said cartridge to flush said membrane.

2. The reverse osmosis system of claim 1 wherein said membrane flushing system comprises a flush servo valve assembly that is actuated by said flush pilot valve assembly during a flush cycle to supply feed water to said feed water storage chamber of said permeate accumulator to force said permeate out of said permeate accumulator.

3. The reverse osmosis system of claim 1 wherein at the end of said flush cycle, said pilot valve assembly routes permeate from said cartridge to said permeate storage chamber of said accumulator and said flush servo valve assembly connects said feed water storage chamber of said accumulator to a drain to refill said accumulator with permeate for a next flushing cycle.

4. The reverse osmosis system of claim 1 wherein said storage tank stores permeate discharged by said reverse osmosis membrane cartridge and comprises:

a tank housing;

an elastomeric bladder contained within said housing in which permeate from said reverse osmosis membrane cartridge is stored; and

wherein an exterior surface of said bladder and an interior surface of said tank housing define a pressurizing region;

and wherein said system control assembly defines an outlet for feed water and an inlet for permeate and contains a control valve assembly responsive to the opening of a dispensing device to place said pressurizing region in communication with feed water to force said permeate from said bladder to said dispensing device when said dispensing device is open.

5. The reverse osmosis system of claim 4 wherein said control valve assembly includes a tank pilot valve that, when said dispensing device is closed, moves a tank servo valve to a position that places said pressurization region in communication with a drain to allow said bladder to be filled with permeate from said reverse osmosis membrane cartridge.

6. The reverse osmosis system of claim 1 further comprising:

a tank housing;

an elastomeric bladder contained within said tank housing in which permeate from said reverse osmosis membrane cartridge is stored; and

wherein an exterior surface of said bladder and an interior surface of said tank housing define a pressurizing region;

and wherein said system control assembly defines an outlet for feed water and an inlet for permeate and contains a control valve assembly responsive to the opening of a dispensing device to place said pressurizing region in communication with feed water to force said permeate from said bladder to said dispensing device when said dispensing device is open.

7. A reverse osmosis system comprising:

a system control assembly including a housing, said control assembly defining an inlet for feed water to be treated and an output from which permeate is discharged;

a reverse osmosis membrane cartridge, external to and removably attached to said housing, said membrane cartridge adapted to receive feed water from said housing and to discharge permeate to said housing; and

a membrane flushing system located within said housing, said flushing system including a permeate accumulator located within said housing and having separate feed water and permeate storage chambers separated by an elastomeric member such that pressurization of said feed water chamber is operative to urge permeate from said permeate chamber under predetermined conditions, and a flush pilot valve assembly that initiates a flush cycle in response to sensing a predetermined permeate pressure in a permeate storage tank, and during said flush cycle said flush pilot valve assembly operative to disconnect feed water from said cartridge and communicate feed water to said feed water chamber of said permeate accumulator whereby permeate from said accumulator is supplied to said cartridge to flush said membrane;

a tank housing in which permeate from said reverse osmosis membrane cartridge is stored;

an elastomeric bladder contained within said tank housing

a pressurizing region defined at least in part by said elastomeric bladder;

and wherein said system control assembly defines an outlet for feed water and an inlet for permeate and contains a control valve assembly responsive to the opening of a dispensing device to place said pressurizing region in communication with feed water to force said permeate from said tank housing to said dispensing device when said dispensing device is open.

8. The reverse osmosis system of claim 1 wherein said storage tank stores permeate discharged by said reverse osmosis membrane cartridge and comprises:

a tank housing in which permeate from said reverse osmosis membrane cartridge is stored;

an elastomeric bladder contained within said tank housing

a pressurizing region defined at least in part by said elastomeric bladder;

and wherein said system control assembly defines an outlet for feed water and an inlet for permeate and contains a control valve assembly responsive to the opening of a dispensing device to place said pressurizing region in communication with feed water to force said permeate from said tank housing to said dispensing device when said dispensing device is open.