Patent ID: 6056048
Filing Date: 2000-05-02
Classification: F28D,F28F

Abstract:
A falling film type heat exchanger tube for promoting a heat exchange between a liquid film on an external surface of a tube and a liquid flowing through inside the tube, comprising:ribs formed as a protrusion on an internal surface of the tube and extending spirally with a suitable distance between adjacent ribs;concavities formed on the external surface of the tube and extending spirally with a suitable distance between adjacent concavities; anda plurality of independent projections formed on the external surface of the tube and laid out spirally, at least one of said projections having a recess formed on its upper surface in such a way that an area of said at least one projection is aligned with said ribs on the internal surface of the tube is lower than another area of said at least one of projection which is aligned with an area between the ribs.