| 摘要 |
A heat exchanger comprising opposed parallel header tubes having circumferentially spaced grooves along he length thereof with inclined sides and a base on the external surface of the groove and spaced annular ribs on the inner surface opposite the grooves. Each groove has a transverse slot therein for receiving open ends of an elongated flat tube. Each header tube is made by performing a rolling operation to form the grooves and ribs. Thereafter, the grooved tubes are punched to form the transverse slots in the base of the grooves. |
