Patent ID: 7124805

Claim:
An elongated flattened tube use in a heat exchanger having a header with a tube slot for receiving the tube, the tube comprising: a pair of oppositely facing broad side walls joined by a pair of oppositely facing convex edge walls to define a uniform transverse cross section over the length of the tube, said cross-section conforming to said tube slot to be received therein, at least one interior flow path enclosed by said walls to direct a fluid flow through the tube; and a pair of localized concave dimples at a desired location spaced from an end of the tube to disrupt said uniform cross section at said location, one of said pair of localized dimples formed in one of said edge walls, the other of said pair of localized dimples in the other of said edge walls, each of said dimples creating a pair of bulges that interfere with the tube slot to limit an insertion depth of said end of the tube into the tube slot.