| 摘要 |
<p>An improved purge unit is provided for establishing an enclosed zone around a weld area for retaining an inert gas. The purge unit is particularly advantageous when welding a branch pipe or pipe connection to a main pipe or header. The purge unit has a cone-shaped member which is inserted into an opening in the header through the branch pipe or connection and is the expanded to establish the enclosed zone around the inside of the weld area. An inert gas is then applied through the purge unit into the zone and the cone-shaped member is subsequently collapsed and withdrawn after the weld is complete. An expandable tube is employed to expand the cone-shaped member and has a rod extending therethrough and connected to the member to provide greater stability for the purge unit.</p> |
