Patent ID: 7892429

Claim:
A batch reverse osmosis system in fluid communication with a fluid reservoir comprising: a pressure vessel having an elongated liner with a first end and a second end, a membrane disposed within the second end having a membrane inlet, a membrane outlet disposed at the second end and a permeate outlet wherein the liner and the pressure vessel have fluid clearance therebetween whereby brine fluid from the membrane recirculates to the first end through the fluid clearance; a recirculation piston disposed proximate the first end, said recirculation piston defining a fluid volume between the recirculation piston and the membrane adjacent to the membrane inlet; a plunger disposed within a housing that is coupled to the pressure vessel, said housing and said plunger defining a chamber, said plunger coupled to an actuator; said housing having a first one-way inlet valve in fluid communication with the fluid reservoir; and a hollow pipe coupled to the actuator, whereby the plunger, the hollow pipe and the piston move in response to the actuator, said hollow pipe having a port, said hollow pipe communicating fluid between said chamber within the housing and said fluid volume within the pressure vessel.