| 摘要 |
<p>A method of laying roofing felt containing bitumen which is solid at ambient temperature and softens at an increased temperature, in which method lengths (7, 8) are brought to overlap each other in overlap zones (11), and welded together by heating the bitumen to the softening temperature. According to the invention an electric current, which is generated by induction, is caused to pass through an electrically conducting heat-emitter (1) arranged within the overlap zone (11), to generate heat in the heat-emitter (1) and emit heat to opposing portions (17, 18) of the lengths (7, 8) so that the bitumen is brought to its softening temperature and the lengths (7, 8) are welded together at the opposing portions (17, 18) to form a tight, continuous overlap joint. A means for welding the lengths is also described for the purpose of which it includes one or two induction apparatus (21; 33) in addition to said heat-emitter (1).</p> |
