JPS56130598A - Heat exchanger - Google Patents

Abstract

PURPOSE: To increase the thermal efficiency of a heat exchanger without reducing the intervals of fins, by forming slits in the fin, and bending the portions of the fin along the slits for preventing development of temperature boundary layer and promoting detachment of foreign matter attached to the fin surface.

CONSTITUTION: Slits 3 are made in a helical fin 2 to extend radially from the base portion located near a heat transfer pipe 1, and the portion 2b of the fin located at one side of a slit 3 is bent along a bending portion 2c in an axial direction of the pipe 1. Resultantly, the helical fin 2 is divided into a multiplicity of substantially sector-shaped sections and the end portion of the bent portion 2b is located almost at the center of an adjacent passage of external fluid B, so that development of temperature boundary layer can be prevented. Further, since the external fluid B is made to flow dividedly through an original passage and an adjacent passage and the flow of external fluid B is rendered smooth, it is enabled to promote detachment of foreign matter or steam contained in the external fluid B if it is attached to the fin surface.

COPYRIGHT: (C)1981,JPO&Japio