Patent ID: 7559355

Claim:
A heat exchanger tube comprising: a flat body having predetermined lengths in longitudinal, vertical and lateral directions, respectively; and a plurality of refrigerant passages formed through the body in the longitudinal direction and arranged in the lateral direction, wherein each of the refrigerant passages comprises: upper and lower circular passages formed in upper and lower sides of the body in the vertical direction with predetermined radii R 1 and R 2 , respectively; a connecting passage for connecting the upper and lower circular passages in a communicating fashion; and turbulence generating portions projected from laterally opposed inside wall portions of the connecting passage with predetermined radii of curvature R 3 and R 4 , respectively, wherein the turbulence generating portions have a projected ratio ranging from 0.1 to 0.43, wherein the projected ratio is obtained by dividing a projected length ‘F’ of the turbulence generating portions which is a distance between an outer common tangential line of the upper and lower circular passages and a tangential line of the turbulence generating portions parallel to the outer common tangential line with a maximum value ‘E’ of diameters of the upper and lower circular passages.