| 摘要 |
A portion 9 of a pig or carrier 7 is rotatable above a longitudinal axis and carries a scissors-type extendible linkage 10 having a platform 11. By rotation of the portion 9, displacement of the carrier 7, and extension of the linkage 10, service means eg. an inflatable plug 15 or cutter 31 on the platform 11 can be maneouvred to be located in a branch conduit 2. The plug 15 includes a metallic part (eg ring 16, Figure 3 not shown) which a metal detector can detect through a lining (Figures 4,5 not shown) which is fitted in a main 1 to determine the position at which a port has to be cut in the lining to coincide with the branch conduit 2. The plug 15 may be provided with a spring-loaded extension (16a, Figure 5) to facilitate detection when a lining (21) spaced a larger distance from the wall of the main 1 is used. <IMAGE> |
