The heat transfer tubes that are improved with the grooved inner surface

摘要

At the same time the tube (10) the inside, the main fin (12) group and the main fin (12) the territory between (24) the intermediate fin which is arranged with specified angle the main fin (12) vis-a-vis (26) it possesses with group. The intermediate fin (26) in order to bring the appearance of lattice condition the main fin (12) vis-a-vis, it is arranged in the concrete example where the inside of pipe surface design is desirable. Group of the 1st roller the main fin (12) and the intermediate fin (26) the board forms the design, at least on side of one side. Furthermore it raises efficiency and it is possible also to use the group of the 2nd roller for the sake of. The pattern which is designed after being copied on the board by the roller, the board is formed by the tube, and is welded, in this way, the internal design of the tube which is obtained includes the intermediate fin which is intended at least, by this invention.