| 摘要 |
<p>PCT No. PCT/GB94/01566 Sec. 371 Date Mar. 12, 1996 Sec. 102(e) Date Mar. 12, 1996 PCT Filed Jul. 19, 1994 PCT Pub. No. WO95/03162 PCT Pub. Date Feb. 2, 1995An electrofusion coupler is slid over one of two thermoplastic pipes, each having a layer or layers of reinforcing fibers between the center of the wall of the pipe and the outside surface of the pipe. The end surfaces are trimmed in a butt fusion machine and the resulting end surfaces are forced against a heater plate. The plate is removed and the end surfaces are forced together. Internal and external beads involving inward and outward flow of material result, the outward flow ensures that there is at the welded joint an inner layer which is free from reinforcement fibers. The external bead is removed and the coupler is slid over the butt fused welded joint and energized to cause it to become fusion welded to the outside of the pipe.</p> |
