| 摘要 |
PURPOSE:To obtain a heat insulating double-layer tube that can be welded without causing flowing out of heat insulating materials and without deteriorating its heat insulating capacity by adhering closely inner and outer tubes at the same time while wrapping an interlayer for heat insulation on the end of the heat insulating double-layer tube. CONSTITUTION:A tube end working jig 3 having tube expanding part 1 of radius of curvature R is thrusted against the end of a heat insulating double layer tube used for the exhaust tube etc. of an automobile. A heat insulating material 12 of the double layer tube is wrapped up in an inner tube 10, and at the same time, expansion and contraction work is performed, and an outer tube 14 is brought into contact with the inner tube. Thus, a heat insulating double-layer tube that does not cause flowing out of heat insulating material and deterioration of heat insulating capacity and warmth keeping capacity. |
