| 摘要 |
A coating unit for forming a coat of polymer material about cutbacks along steel cylinders joined by welding and having an extruder (36) including an extrusion outlet (38) facing and close to the cutback (18) for extruding a protective sheet (22) wide enough to overlap coatings (13) adjacent to cutback (18), close to the cutback (18); and means (34, 35, 49) for rotating the extruder (36) and the extrusion outlet (38) about the cutback (18), and keeping the extrusion outlet (38) facing and close to the cutback (18) so as to simultaneously wind said protective sheet (22) about the cutback (18), form said coat (21) of polymer material in a single pass, cover the entire cutback (18), and overlap coatings (13). |
