Patent ID: 8235098
Filing Date: 2012-08-07
Classification: F28D,F28F

Abstract:
1. A tube stack for a heat exchanger, comprising: a plurality of flat tubes stacked one upon another, each flat tube having substantially flat opposite faces and a plurality of spaced-apart dimples formed on each of the faces, the dimples projecting outwardly away from an interior passage of each tube, a height of the dimples being defined by outermost surfaces of the dimples, at least some of the dimples on each face having an elongate plan shape as viewed perpendicular to the respective face such that each elongate dimple has a length along a major axis greater than a width of the dimple along a minor axis, at least some of the elongate dimples being obliquely oriented with the major axes forming oblique angles with a longitudinal axis of the tube, wherein the obliquely oriented elongate dimples are positioned such that the obliquely oriented elongate dimples on opposing faces of the tubes contact one another to space the opposing faces apart and the major axes of each contacting pair of elongate dimples are non-parallel to each other, wherein the elongate dimples of each flat tube are arranged on each face in a plurality of rows extending parallel to the longitudinal axis and spaced apart in a width direction of the flat tube, wherein the elongate dimples in one of the rows on each face have the major axes oriented substantially parallel to the longitudinal axis of the tube, and the elongate dimples in other rows on each face have the major axes oriented obliquely to the longitudinal axis, and wherein the obliquely oriented elongate dimples in one of the rows on each face have the major axes inclined in an opposite direction from the longitudinal axis in comparison to the obliquely oriented elongate dimples in another of the rows.