METHOD FOR ADJUSTING SPECIFIC RESISTANCE OF ULTRAPURE WATER AND PURE-WATER MAKING APPARATUS USING THE SAME

摘要

PROBLEM TO BE SOLVED: To stably adjust the specific resistance value of ultrapure water constant over a long period of time without using carbon dioxide by bringing ultrapure water showing specific resistance into contact with a bicarbonate ion type strong basic anion exchange resin or an ammonium ion type strong acidic cation exchange resin. ;SOLUTION: Raw water such as industrial water is sent to a primary pure water making apparatus 1 by a liquid sending pump and, herein, flocculation filtering or deionizing treatment is performed to make pure water with specific resistance of about 10 MΩ.cm or more. Next, treated water is primarily stored in a pure water tank 2 and subsequently sent to a secondary pure water making apparatus 3 and, herein, ultrapure water with specific resistance of about 18 MΩ.cm or more from which impurities are removed to the utmost is made. The obtained ultrapure water is sent to a specific resistance adjusting apparatus 4 packed with a bicarbonate ion type strong basic anion exchange resin or an ammonium ion type strong acidic cation exchange resin. by a branch pipe 7 and the specific resistance of ultrapure water is adjusted.;COPYRIGHT: (C)1999,JPO