Super pure water production device and production mannered null primary pure water

摘要

PROBLEM TO BE SOLVED: To obtain a total carbonic acid concentration measuring apparatus by which a carbonic acid concentration in pure water or ultrapure water can be detected simply and with high accuracy, by a method wherein a total carbonic acid concentration is computed on the basis of the measured value of the conductivity or the resistivity of the pure water. ;SOLUTION: A resistivity sensor 6A is installed on the entrance side of a mixed-bed ion exchange apparatus 4, and the resistivity of water flowing into the exchange apparatus 4 is measured by a resistivity meter 7A. On the other hand, a resistivity sensor 6B is installed on the exit side of the exchange apparatus 4, and the resistivity of water which flows out is measured by a resistivity meter 7B. Its measurement can be performed instantaneously. Consequently, even when a change in the resistivity is large, the measurement can be performed continuously, stably and with high accuracy. Measured values including a water passage amount by a flowmeter 8 are inputted to a computing device 9. By using a specific calculating expression, the total carbonic acid concentration of the water which flows into and total carbonic acid concentration of the water which flows out are computed. In addition, also the carbonic acid load amount of the exchange apparatus 4 and the carbonic acid load factor (the utilization factor) of an ion-exchange resin can be found. As a result, it is possible to estimate the time in which the ion-exchange resin reaches a breakthrough, i.e., the replacement time or the regeneration time of the ion-exchange apparatus 4.;COPYRIGHT: (C)1999,JPO