AUTOMATIC CONCENTRATION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an automatic concentration control device which is capable of keeping a solution containing salts composed of an acid and a base substantially or reversibly constant in concentration with the least amount of a replenisher, where at least either the acid or the base is volatile. SOLUTION: A solution contains salts composed of an acid and a base, where the acid and/or the base is volatile. This automatic concentration control device replenishes the above solution with a volatile acid and/or a volatile base.