US Patent 8741148 Water treatment system

A water treatment system including a reverse osmosis module and a control valve controlling communication between a water source and the module. A feedwater biased storage tank stores permeate and its pressurization by feedwater is controlled by a feedwater control valve. Flow of signal pressure to a signal pressure chamber of the feedwater control valve is restricted to reduce the rate at which a fluid generated force is applied. A check valve in parallel with the restriction allows relatively unrestricted flow out of the signal chamber when signal pressure is terminated. A tank pressurization control valve controls the operation of the feedwater control valve and controls the pressurization of a feedwater biasing chamber in the storage tank. Per-meate is stored in an accumulator for flushing the reverse osmosis module when the storage tank reaches a predetermined limit. Cleaning substances or additives can be introduced into the system.