| 摘要 |
Plastic pipes (22, 23) are joined by electrothermal welding using a heating mat (10) which covers the entire circumference of the butt joint (26). During welding the heating mat (10) is enclosed and held by a removable, heat resistant and insulating pressure system (28, 29). Preferably the heating mat (10) consists of plastic covered heating wire laid in a zigzag, along the pipes (22, 24). The plastic covering melts as the joint is formed and the outside diameter of the joint is only a little greater than that of the pipes. The mat made in two connected halves, covers the ends of the pipes (22, 24). The mat is retained by a quick release coupling (34), with an optional tightening system. |
