| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat exchanger in which cathodic protection effectively functions even when a long time has elapsed after the combustion is stopped and the evaporation of condensed water has advanced and a method and device for cathodically protecting the heat exchanger. SOLUTION: An electrode section 60 is positioned near the cathodically protected part to be protected front corrosion by condensed water of a heat exchanger 50 for recovering latent heat and applies a prescribed voltage across the anode of the electrode section 60 and the cathodically protected part of the heat exchanger 50 which works as a cathode from a constant-voltage power source 81. The voltage is continuously applied even after the combustion is stopped. When the current value detected by means of a current detector 82 exceeds a prescribed value, a water spray control section 84 discriminates that the condensed water is concentrated and sprays water upon the heat exchanger 50 by opening a stop cock 72. Consequently, the action of cathodic protection can be maintained continuously for a long period, because the condensed water is diluted and washed away and, at the same time, the heat exchanger 50 is maintained in a wet state. |
