| 摘要 |
PURPOSE:To increase the surface area of heat transmitting face and to prevent the formation of thick liquid film on the surface by performing tooth-form deforming of the outer periphery of fins using a disk tool having gear-shaped outer periphery continuously after manufacture of a low fin tube. CONSTITUTION:A discoidal tool having gear-shaped outer periphery is attached behind a group of discoidal tools for fin forming of a low fin forming machine, and fins are formed by above-mentioned tool group. When deforming is executed on the outer periphery of fins of the low fin tube along its longitudinal direction by using a gear-shaped discoidal tool, crests 1 and troughs 3 as shown in a figure are formed continuously and alternately. Sectional form between facing slope 1' and 1' is as shown in the figure. As the heat transmitting tube obtained by this process often generates burrs and projections, it is desirable to make brushing lightly by using a wire brush. |
