| 摘要 |
PURPOSE:To improve the heat transfer performance of the title heat transfer pipe by providing in a heat transfer pipe for a condenser in a low heat fall power plant, a plurality of peripherally directed saw-tooth shaped rib projections on the inner surface of said pipe and a plurality of vertical grooves each of which has a corrugated section on the outer surface thereof. CONSTITUTION:A strip-like plate material 1 consisting of a corrosion-resisting material such as titanium or stainless steel is subjected to plastic working using rolling roll thereby to form a plurality of saw-tooth shaped rib projections 3 rectangularly with respect to the longitudinal direction of the pipe and a plurality of flat portions in the longitudinal direction thereof. The plate material 1 used in the inner side of the pipe is bent in a cylindrical shape and joints are welded thereby to fabricate a laterally grooved saw-tooth shaped pipe 4. A vertical groove pipe 5 made of a material having a good workability such as aluminum, brass or the like is fabricated by drawing. Into the inside of the pipe 5 the pipe 4 is inserted. The thus formed dual pipe is inserted into dies having on the inner surface a final vertical groove shape and is filled at the inner part with a filler made of natural rubber, and pressure is applied to the pipe from both ends thereof the press-fit the pipe to complete a heat transfer pipe 6. |
