| 摘要 |
PURPOSE:To eliminate the need for exchanging a seal with the stepless change in the outside diameter of a long-sized pipe and to improve the yield of pressurizing gas with a device which supplies the gas under pressure to the inside of the long-sized pipe and seals hermetically the same by specifying the enaging and welding of a welding chamber and the long-sized pipe. CONSTITUTION:A long-sized pipe 1 attached with plugs 2, 3 at both ends is held by a chuck 8 and the end face 3b on the outside circumference of the small hole 3a of the plug 3 is pressed to the surface of a seal 7 attached to the gas feed port 4b of a welding chamber 4. The seal 7 is formed of a pressure and heat resistant elastic material which prevents leakage of the pressure when gas is supplied under pressure from the chamber 4 to the pipe 1. The end face 3b is tapered to increase the contact area with the seal 7. The bore of the port 4b is smaller than the bore of the seal 7 and is eventually smaller than the outside diameter of the pipe 1. The air in the pipe 1 and the chamber 4 is evacuated through a piping 5 then the gas is in turn supplied under pressure through the pipe 5 into said pipe and chamber and thereafter a laser is applied through an output lens 9 and a transmission window 10 to the hole 3a to weld and seal hermetically the hole. The need for exchanging the seal 7 is thus eliminated and the inside volume of the chamber 4 is made smaller. |
