| 摘要 |
PROBLEM TO BE SOLVED: To quickly and easily perform the quantitative evaluation of fouling state of a metal surface and to easily perform the online monitoring of corrosion thereof by heating a metal to a temperature causin easy adhesion of scale and slime, and measuring the scale or slime adhesion quantity to the metal. SOLUTION: A metal piece 2a is heated by a heater to 30-45 deg.C suitable for adhesion of slime. A metal piece 2a is heated by a heater to 70 deg.C or higher suitable for scale precipitation and sensitive to stress corrosion cracking. The potential change of each metal piece 2a, 2b is simultaneously measured by use of a potential measuring apparatus 4 using a reference electrode 3. After dipping for a fixed time, the fouling adhesion quantities of the metal pieces 2a, 2b are determined by use of a specified expression. The excessive addition of an oxidant into a cooling water system is assumed when both the potentials of the metal pieces 2a, 2b rise to the noble side, and the slime obstacle generation when 2a rises to the nozzle side but 2b does not rise. Further, the danger of microbial corrosion is assumed when the potential of 2a suddenly transfers to the base side, and the danger of clearance corrosion and stress corrosion cracking when the potential of 2b suddenly transfers to the base side.
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