Method and system for operating a shut-off valve of a filtration system

1. A system comprising:

a filtration assembly having a feed water line, a concentrate line, and a permeate line;

a shut-off valve coupled between the permeate line and the feed water line, the shut-off valve opening the feed water line when a faucet that is connected to the permeate line is opened and closing the feed water line when the faucet that is connected to the permeate line is closed; and

an energy storage member positioned within a container located within the permeate line, said container including a permeate inlet and a permeate outlet, said member enclosing a space not fluidly communicating with the permeate line, the energy storage member configured to compress when the faucet is closed and expands when pressure within the permeate line drops below a certain level causing the shut-off valve to fully close.

2. The system of claim 1 , wherein the energy storage member includes a compressible member.

3. The system of claim 1 , wherein the energy storage member includes an air-filled elastomeric member.

4. The system of claim 1 , wherein the energy storage member includes an air-filled hollow compressible member which is located in the permeate line and has an internal pressure of between about 2 psi and about 10 psi.

5. A system comprising:

a water filtration assembly including a feed water line, a concentrate line, and a permeate line;

a shut-off valve between the permeate line and the feed water line, wherein the shut-off valve opens when a pressure differential level between the permeate line and the feed water line is less than a first level and closes when the pressure differential level between the permeate line and the feed water line is greater than a second level which is higher than the first level; and

a compressible member positioned within a container located in the permeate line, said container including a permeate inlet and a permeate outlet, said member enclosing a space not fluidly communicating with the permeate line, the compressible member configured to expand to increase the pressure differential between the permeate line and the feed water line above the second level causing the shut-off valve to fully close.

6. The system of claim 5 , wherein the compressible member contracts after a faucet that is coupled to the permeate line is closed.

7. The system of claim 5 , further comprising a check valve within the permeate line that maintains pressure within the permeate line above the second level as long as a faucet that is coupled to the permeate line remains closed.

8. The system of claim 5 , wherein the compressible member includes an air-filled elastomeric member.

9. The system of claim 5 , wherein the compressible member contracts before the compressible member expands.

10. A system comprising: a water filtration assembly including a feed water line, a concentrate line, and a permeate line;

a shut-off valve between the permeate line and the feed water line, wherein the shut-off valve opens when a pressure differential level between the permeate line and the feed water line is less than a first level and closes when the pressure differential level between the permeate line and the feed water line is greater than a second level which is higher than the first level; and

a member positioned within a container located in the permeate line, said container including a permeate inlet and a permeate outlet, said member enclosing a space not fluidly communicating with the permeate line, the member configured to compress and then to expand increasing the pressure differential between the permeate line and the feed water line above the second level causing the shut-off valve to fully close.

11. The system of claim 10 , wherein the member includes an air-filled elastomeric member.