| 摘要 |
An induction pre-heating apparatus for use in welding a first object to the exterior surface of a second object is described. The apparatus comprises at least one elongate electrical conductor having at least one active length with a non-circular transverse cross-section. The non-circular cross-section is typically a flattened cross-section, with a height shorter than its width. The first and second objects may typically be pipes, and the induction pre-heating apparatus may be used in a subsea, hot-tapping procedure. The apparatus may also include an EM field focussing means (typically comprised of a plurality of laminations), which serves to direct the EM field to a required area, which may be adjacent to the induction pre-heating apparatus as opposed to underneath it. Advantages include that the pre-heating can be applied directly to the weld zone, whilst preventing over-heating of other neighbouring areas. |
