| 摘要 |
<p>The pipe element is provided with coiled and profiled helical metal strip (1). Each turn of metal strip forms waves (2',2'',20',20'',200',200'') of pipe element and cylindrical extension portion (3,30,300). Adjacent turns of metal strip are joined with each other by using sealing welded seam (6). A cylindrical tube portion (4,40,400) is provided between the adjacent waves of pipe elements so that the sealing welded seam is located in pipe element and extension portion. The waves of pipe elements are provided in frictional contact with the tube portion.</p> |
