Curved tubes of a heat exchanger

A tube matrix for a heat exchanger having two spaced ducts to which the tube matrix is connected for conveying a fluid from one duct to the other, said tube matrix comprising at least one row of spaced heat exchange tubes, each of said tubes having first and second ends at which the tubes are respectively fixedly secured to the two ducts so that said row of tubes lies in a common plane, each said tube being bent to form a generally S-shape in said plane, each said tube having two peaks with points of maximum offset and an intermediate point between said peaks, and successive spacer means at each said point of maximum offset and at said intermediate point for keeping adjacent tubes spaced from one another and fixedly secured at said points, each said tube including respective contiguous sections between said spacer means at said two points of maximum offset and said first and second tube ends, each said section being free and unsupported between respective spacer means and including two bent portions of opposite but the same curvature, said two bent portions of each contiguous section of the tube being substantially equal in length, and defining a point of inflection midway of said contiguous section, each said tube having tangents at said first and second ends and at said points, said tangents extending substantially parallel to one another.