| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a heat exchanger, in which production efficiency can be improved by efficiently oxidizing the inside surface of a copper tube. SOLUTION: In a brazing furnace 11, respective zones for a heating action in a non-oxidizing atmosphere, a cooling action in a non-oxidizing atmosphere, and an oxidizing action in an oxidizing atmosphere are provided successively in the direction for transferring an object to be brazed. The object X, in which a copper tube for passing water is to be brazed on a water-heater body, is transferred to the heating action zone for the brazing process. The brazed object X is transferred to the cooling action zone in the non-oxidizing atmosphere for cooling, and it is further transferred to the oxidizing action zone in an oxidizing atmosphere. A fluid is pressure-fed into the copper tube in the brazed object X to wash out oxidation products in the inside of the tube. |
