摘要 |
A heat exchange unit includes first and second plates, which are identical in configuration in a central irregularity pattern section, but different in configuration in a peripheral area. The first plate has first terraced sections projecting outward relative to a remaining part having a first flat section. The second plate has a second terraced section projecting outward relative to a remaining part having a second flat section. The first and second plates are placed alternately one upon another so that surfaces of said irregularity pattern sections face a same direction. The first terraced sections of the first plates come into contact with the second flat sections of the second plates and the first flat sections of the first plates come into contact with the second terraced sections of the second plates. The first and second plates are welded to each other at contact areas.
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