Patent ID: 8580118

Claim:
A process for regenerating a water softening system, said system of the type that removes multivalent ions from water provided by a hard water source, the water softening system including a softener tank through which the water from the source passes from an upstream end thereof to a downstream end thereof; a brine tank for holding a monovalent regenerating brine solution; a first diverter valve supplying liquid selectively from either the water source or the brine tank to the upstream end of the softener tank; a nanofilter having upstream and downstream sides, and allowing monovalent ions to pass to the downstream side and retaining multivalent ions on the upstream side; a second diverter valve connected to receive liquid from the downstream end of the softener tank and to selectively supply liquid at a first output to a water distribution system and to a second output; a connection between the downstream end of the nanofilter and the brine tank; a pump receiving liquid from the second output of the second diverter valve and supplying pressurized liquid to the upstream side of the nanofilter; a throttling valve connected between the upstream side of the nanofilter and the drain; and a third diverter valve having an input and first and second selectable outputs, said input connected to receive liquid from the second output of the second diverter valve, said first output of the third diverter valve connected to the pump, and said second output of the third diverter valve connected to another destination, said process comprising the steps of: a) operating the first diverter valve to pass brine solution from the brine tank through the softener tank of the water softening system; b) operating the second diverter valve to direct liquid from the downstream end of the softener tank to the second output of the second diverter valve; c) directing liquid on the downstream side of the nanofilter to the brine tank; d) directing liquid on the upstream side of the nanofilter to a drain; e) operating the third diverter valve during a first phase of a regeneration cycle to supply liquid from the second output of the second diverter valve to the first output of the third diverter valve; and f) during a second phase of the regeneration cycle which follows the first phase of the regeneration cycle, operating the third diverter valve to direct liquid from the second diverter valve to the second output of the third diverter valve.