| 摘要 |
PURPOSE:To cheaply prevent the leakage of heat transfer medium between a sheet metal and tubes with good result by a method wherein tubes locating in the neighborhood of both ends in the longitudinal direction of the sheet metal are soldered to the sheet metal with high tin solder and the remaining tubes are soldered to the sheet metal with low tin solder. CONSTITUTION:The tubes 1 located in the neighborhood of both ends or in regions b and c at the left and right ends in the longitudinal direction of the sheet metal 4 viewing them on the plane of the sheet metal 4 are soldered to the sheet metal 4 with high tin solder and the remaining tubes located in a region d are soldered to the sheet metal 4 with low tin solder. A cheap heat exchanger with no leakage trouble is obtained by using high tin solder, which has excellent soldering property and as well as is valuable, only in the regions b and c or the regions, at which the leakage of heat transfer medium is apt to occur, and as well as by using low tin solder in the remaining region d in such a manner as mentioned above. |
