| 摘要 |
597,116. Coiling helical tubes ; corrugating ; welding. METALLSCHLAUCHFABRIK AKT.-GES. Aug. 10, 1945, No. 20536. Convention date, Aug. 12, 1944. [Classes 83 (ii) and 83 (iv)] In making corrugated tubes by winding profiled strip on a smooth mandrel with an electrode wire filling the crests of the tube and welding the seam, the tube is first made with small corrugations and intermediate straight portions are then rolled to provide deeper corrugations. Strip 3 is coiled on a mandrel 1 and the seam is welded by a roller electrode 4, an inserted wire 2 forming the other electrode. The tube is further corrugated by rollers 6 or by a rotary disc, |
