Flat tube with plurality of holes usable in heat-exchange apparatus and the heat-exchange apparatus containing such tubes

摘要

A multi-bored flat tube (1) has outermost unit passages (11A) located at both ends of the tube (1) and intermediate unit passages (11) between the outermost unit passages. The outermost unit passage (11A) has a circular-based inner surface (12) in cross-section, such as a circumferentially smooth curved shape in cross-section like a perfect circular shape or elliptical shape, or has a circular-based inner surface (12) in cross-section having a plurality of inner fins (15) extending in a longitudinal direction of the tube. The intermediate unit passage (11) has a non-circular based cross-sectional shape, such as rectangular, triangular, trapezoidal, or circular based shape including a plurality of inner fins (15). The tube (1) is strong against being hit by a stone and has a high heat exchanging performance.