| 摘要 |
PURPOSE:To prolong the life of tubes and to enable expanding of hundreds of heat transmitting tubes by using tubes made of shape memory alloy as tubes for expanding. CONSTITUTION:A cylindrical expanding tube 15 made of shape memory alloy such as ''Nichinol '' is placed on the outer periphery of expanded part of a heat transmitting tube 6 of a mandrel 14, and stares a state of cold working to true roundness not to touch the heat transmitting tube 6. A space 16 is formed at the inside of this tube 15 for tube expansion and a supporting member 18 in which many through-holes 17 are pierced is placed therein. A fluid channel 19 pierced in the axial direction of the mandrel 14 is opened in the supporting member 18. Then, the mandrel 14 is inserted to a specified position of the heat transmitting tube 6, and pressure oil is poured in from the fluid channel 19. The pressure oil passes through through-holes 17 in the supporting member 18 and flows in between the supporting member 18 and the tube 15 for tube expansion, and presses the tube 15 for tube expansion outward, and expands the heat transmitting tube 6. |
