Patent ID: 6655451
Filing Date: 2003-12-02
Classification: B01D,F28F

Abstract:
A falling film type heat transfer tube for exchanging heat between a liquid film formed by liquid dripping onto an external surface of the tube and a fluid flowing through the tube, comprising:a tube body; a plurality of separate projections formed on an external surface of the tube; and a ridge formed on an internal surface of the tube, the ridge having a convex shape and extending spirally; wherein said projections are divided into a plurality of projection groups; in each projection group, a plurality of uniformly shaped projections are arranged spirally so that pitches between adjacent projections are uniform; the longitudinal directions of said projection groups are in parallel to one another; and a shape of or pitch for said projections forming at least one projection group is different from shapes of or pitches for said projections forming other projection groups.