Patent ID: 7258159

Claim:
A heat exchanger, comprising: a plurality of flat tubes stacked in layers, including each of the plurality of the flat tubes having a pair of tube sheets facing each other and joined together, the tube sheets have a flat part, a depressed recess part having end portions and extending in a longitudinal direction, and a cylindrical tank protruding from the end portions of the recess part, the tube sheet being one of a first tube sheet and a second tube sheet, the first tube sheet having a first type of tank positioned at each end thereof, the second tube sheet having the first type of tank at one end portion of the recess part and a second type of tank at the other end portion of the recess part, identifiers provided at each end of the second tube sheet, the identifiers distinguishing the second tube sheet from the first tube sheet when viewed externally of the stacked flat tubes, and a mark provided at one of the identifiers of the second tube sheet.