Method and apparatus for installing a duct around a longitunal member present at the stretch of installation

Apparatus for installing a tubular element of a kind generally indicated as duct (1) around a longitudinal member (3), the apparatus comprising a duct propelling device (17) including:

• pulling means (43;
• 65) provided with coupling means (19;
• 55;
• 81) for a tension-proof coupling to a free end (9) of the longitudinal member, and
• pushing means (41;
• 63) for pushing the duct over the free end (9) and further portions of the longitudinal member (3),
• wherein
• the duct propelling device (17) comprises a common housing (39;
• 61) provided with a duct transit channel (45;
• 67), the pulling means include electromagnetic, preferably magnetic means provided with a duct transit channel surrounding part (49;
• 69) and a corresponding core member (53;
• 73), and the pushing means include duct transporting means (47;
• 85, 87), the duct transit channel surrounding part and the transporting means having been arranged in the common housing around sections (45.1/2;
• 67.1/2) of the duct transit channel, the core member being provided with coupling means (55;
• 81) for coupling to the free end of the longitudinal member, and the duct transit channel surrounding part being such a way that during operation the free end of the longitudinal member coupled to the core member is maintainable in a substantially fixed position with respect to the transporting means.