抄録
In the process of manufacturing aluminum heat exchangers, they usually are brazed in the furnace filled with nitrogen below 20ppm oxygen concentration. This paper proposes a new method to make the environment above. Firstly, the chamber (as a model of the furnace) is evacuated to a certain pressure. Secondary, it is filled with nitrogen gas. And then, it is evacuated again to 20ppm oxygen concentration. This method is found to reduce the amount of nitrogen gas consumption and the time until the oxygen concentration falls enough.
