| 摘要 |
PURPOSE:To stably and accurately measure pH in a wide temp. range without receiving the effect of water quality, by calculating the elution speed of a metal ion in the metal in a solution to be measured and calculating pH of the solution to be measured on the basis of said speed. CONSTITUTION:Flow passage valve 1, 21 are opened by the operation of a valve control device 7 receiving the control signal of the main control device 8 of a pH measuring apparatus and the temp. of sample water branched from the flow passage system of high temp. water is measured by the thermometer 2 of a measuring line 42. Further, the concn. of dissolved oxygen is measured by dissolved oxygen densitometer 3 for high temp. and the temp. of sample water and the concn. of oxygen are applied to the control device 8. Next, electric conductivity is measured by an electric conductivity meter 5 and sample water is made to flow to an elution column 4 packed with metal oxide and metal ion corresponding to pH is eluted from a metal. The conductivity of sample water when the metal ion is eluted is measured by an electric conductivity meter 10 and the measured value is outputted to the control device 8. The metal ion is collected by a high temp. filter 6 and, thereafter, high temp. water is returned to the flow passage system 41 to accurately measure pH.
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