| 摘要 |
PROBLEM TO BE SOLVED: To stably reduce water controlled with a desired specific resistivity. SOLUTION: Raw water is pretreated in a pretreatment step, and part of it is deionized by a deionizing means 5. The remainder is combed with deionized water without being deionized. By measuring the specific resistivity C2 of the combined water and controlling the amount of the non-deionized water to be combined with the deionized water without being deionized according to the measured value, water of a specified resistivity can be obtained. Further, by pouring a carbon dioxide gas into the non-deionized water according to the measured value C1 of the resistivity of the raw water, its resistivity is roughly controlled. By finely controlling the resistivity by pouring carbonic acid solution from a carbonic acid dissolution tank 6, water of a specified controlled resistivity can be stably produced from raw water of a markedly fluctuating resistivity.
|
