| 摘要 |
PURPOSE:To reduce capacity of a vacuum discharge device, by using a flexible hollow tube for pressing in compressed air, tightly sealing the inside of a pipe- like object to be welded and the atmospheric part, and its outside circumference and the atmospheric part, and reducing the vacuum capacity. CONSTITUTION:Leakage by pipes to be welded 2a, 2b, which have been installed to a vacuum chamber 3 is obstructed by rotary seals 4, 5 provided with hollow tubes 4a, 5a, respectively, and environment for generating an electronic beam B is reduced as less as possible. Compressed ar is pressed into the flexible hollow tubes 4a, 5a from a pipe 10, the atmosphere and the vacuum chamber 3 are sealed in a suitable part of the pipes to be welded 2a, 2b, and the chamber 3 is made vacuum by a pipe 9c. Also, the rotary seal 4 secures a position correctly by a clamping mechanism 4b, prevents displacement by a guide roll 15, and maintains a smooth operation by vacuum drawing of a rotating part by a vacuum discharge pipe 9b. |
