PURPOSE: To prevent the corrosion of a dew water discharge pipe and the like by a method wherein bypass air for combustion and drops of dew water generating from a combustion gas are brought into contact with each other to a sufficient degree at an opening provided in a dew water collecting section.
CONSTITUTION: The water contained in the combustion gas generating at the time of absroption of heat from the gas by a condensing heat exchanger 3 is collected in the dew water collecting section 6, and the dew water drops down into a dew water receiving section 8 from the opening 7 provided in the dew water collecting section 6. In this case, the drops of dew water are brought into full contact with the bypass air for combustion sucked from the opening 7 so that CO2 contained in the dew water is removed. As a consequence, the pH of the dew water changes from 4 to neutral and the corrosion of the discharge pipe 9 due to the dew water is prevented.
TANAKA EIICHI
INDOU MASAHIRO
FUJISHITA KAZUO
