| 摘要 |
PURPOSE:To seal the weld point of an electric welded tube and the neighborhood thereof from the atmosphere by making internal sealing members for said tube expandable and contractable like an umbrella in a radial direction. CONSTITUTION:A cylinder 9 is actuated by a remote operation to slide a movable member 6 which expands or contracts a sealing member 4 like an umbrella. The members 4 provided before and behind the weld point 3 are expanded radially by the operation of the cylinders 9 to contact slidingly with the inside circumferential wall of a blank tube 1 by which the inside of the tube including the point 3 is shielded from the atmospheric air. The members 4 consisting of a rubber-like elastic material and do not damage the inside wall of the tube. Since the circumferential edges of the members 4 are bent in the advance direction of the tube 1, the inside of the tube is sealed positively against the minute fluctuation in the shape of the tube. |
