To provide a water softener which prevents a pH decrease of treated soft water with a low-cost constitution and facilitates regeneration of a cation-exchange resin.
The water softener includes a water softening means 5 incorporating a cation-exchange resin 4, an electrolysis means 2 separated into a cathode chamber 12 and an anode chamber 11 connected to the water softening means 5 on the downstream side to electrolyze water, an acidic water tank 3 for storing acidic water, and a circulating pump 8 for supplying the acidic water in the acidic water tank 3 to the water softening means 5 during the regeneration of the cation-exchange resin 4. When soft water is used, acidic water of the anode chamber 11 is stored in the acidic water tank 3, and alkaline water of the cathode chamber 12 is supplied to the water softening means 5. When soft water is used, acidic water having a high hydrogen ion concentration is generated in the anode chamber 11 without wastefully using swill water, and the alkaline water whose pH is increased in the cathode chamber 12 is made to pass through the water softening means 5 to prevent the pH decrease of treated soft water. When the cation-exchange resin 4 is regenerated, the regeneration is efficiently performed with the acidic water of the acidic water tank 3.
OKETA TAKEMI
Hiroki Naito
Daisuke Nagano