| 摘要 |
PURPOSE:To provide a heat exchanger having no corrosion caused by a acid dew formation water by a method wherein a coating film of zinc is applied to a surface of a heat exchanger made of aluminum base material, an epoxy resin undercoating film is applied to the surface and the surface is applied with a normal temperature set fluorine coating film. CONSTITUTION:As heat absorption fins 3 are heated while fluid is passing in a heat exchanging tube 2, the fluid is circulated while being heated. However, since a drum 1 and the heat absorption fins 3 are partially cooled by fluid flowing within the heat exchanging tube 2, NOX, SOX and CO2 or the like in combustion exhausting gas are dissolved in the dew formation water, resulting in that the water becomes acid dew formation water containing nitric acid, sulfuric acid or the like having a high corrosion characteristic. In turn, an extremity end of each of the heat absorption fins 3 shows a high temperature more than 250 deg.C. However, since the surface of the heat exchanger is provided with a normal temperature set type fluorine type coating film 8, it has a superior heat resistant characteristic capable of sufficiently enduring against a high temperature of more than 300 deg.C and capable of enduring against acids such as nitric acid and sulfuric acid or the like. In turn, even if the normal temperature set type fluorine coating film 8 and the epoxy resin undercoating film 7 are deteriorated, the lower zinc coating film layer 6 may act as a sacrifice anode, resulting in that aluminum base material 4 is anti-corroded. |
