| 摘要 |
1422754 Coupling pipes P O SUNDIN 25 Feb 1974 [10 April 1973] 8389/74 Heading F2G [Also in Division H5] Pipes 1 and 2 of polyethylene are joined by a connecting piece also of polyethylene and having tubular sections 3, 4 fitting over the pipes 1, 2 and a bellows fold 5 which will take up movement due to temperature variations after the sections 3, 4 have been fixed to the pipes 1, 2 by welds 6. Apparatus for forming the welds 6 is described this being shown in part section in Fig. 4 and comprises an annular body formed of two ring halves, as 10, hinged together and lockable in place about the pipe 1 and connector section 3 by a clasp (not shown). Each ring half is provided with an electric resistance heating element 13 and its inner surface is composed of surfaces 20, 22 to rest on the pipe 1 and connector section 3 respectively and joined by a surface 21 to form the outer face of the weld. After heating pressure is applied axially by means of handles 19 attached to load distributing rings 18 on the ring halves, as 10, or attached directly to the ring halves, and this axial pressure forms the weld. Further material can be added to the weld if desired. In an alternative construction the handles are mounted on the resistance heating elements before they enter into the appropriate ring half. |
