2008 Volume 57 Issue 2 Pages 89-95
Diagnosis of water quality for polarity reversal in galvanized steel pipes were carried out by using Mahalanobis Distance (MD). Cooling and heating water quality data (109 data of no corrosion trouble and 20 data of corrosion trouble) and coolant water quality data (173 data of no corrosion trouble and 12 data of corrosion trouble) were used for the diagnosis of water quality.
In the diagnosis of cooling and heating water quality, the misjudgment was 1 among 20 troubled data, thus this diagnosis was high accuracy. In diagnosis of coolant water, the misjudgments were 3 among 12 troubled data. Since many kinds of dosing are implemented in coolant water, dosing influenced the water quality remarkably and the accuracy of diagnosis of water quality using MD decreased.