Patent ID: 6220344
Filing Date: 2001-04-24
Classification: F28D

Abstract:
A heat-exchanger tube comprising:an inner tube wall centered on an axis, formed with an outwardly projecting helical ridge of predetermined hand and having a helical outer surface, and forming an outwardly open helical groove delimited by the ridge;an outer tube wall centered on an axis, formed with an inwardly projecting helical ridge of the same hand as the inner-tube ridge, having a helical inner surface, and forming an inwardly open helical groove delimited by the outer-tube ridge, the inner tube being coaxially received in the outer tube with the grooves together forming a helical passage having a plurality of turns and the surfaces radially confronting and spaced from each other to form an axial passage for fluid communication between adjacent turns of the helical passage; andmeans for feeding a fluid to one end of the helical passage and withdrawing the fluid from an opposite end with flow of the fluid helically along the helical passage and axially through the axial passage.