| 摘要 |
<p>Method for providing a rigid duct (1) with an annular seal located on the inner surface of a mouth of the same rigid duct (1) or the outer surface thereof. In a first step of the method the seal, comprising at least two annular members (10, 20), is made through injection-moulding in a mould (100); parts (102, 104, 110) of such mould are then removed so as to expose the moulded seal, while enabling it to stay attached to a pedestal (73), belonging to a stationary part (120) of the mould, along one (20) of said annular members thereof, whereas a second annular member (10) is free and is brought close to the duct (1); and, finally, between the free surface of the seal and the surface of the duct (1) there is provided, through injection-moulding, at least an annular attachment member (30) that makes the seal firmly joined to, i.e. integral with the duct.</p> |
