| 摘要 |
PURPOSE:To manufacture a double pipe which has excellent sticking properties, a superior heat quantity flow rate ratio, and superior boundary heat conduction resistance by fitting an internal tube into an external pipe which has a greater coefficient of thermal expansion than the internal pipe and introducing a high- temperature pressurized fluid into the pipe, and thus expanding the both in press contact. CONSTITUTION:An external pipe uses a metal, such as Al, which usefully accelerates heat conduction and is surface-worked easily, and is provided frequently with longitudinal grooves, raised fins, transfer fins, etc., on the external surface for accelerating heat conduction. An internal tube suitably uses a material, such as Ti, which has corrosion resistance and enough hardness to resist mechanical internal pipe surface washing for a countermeasure to contamination, and is reducible in thickness for reduction in cost. As a pressurized fluid, about 250- 400kg/cm<2> pressurized water is used favorably, and working temperature is only about 20-30 deg.C higher than in-use temperature while maximum temperature is determined in accordance with the creep characteristics of the materials with attention paid to work environment and safety. |
