| 摘要 |
PURPOSE: To realize coupling of large-diameter pipes by forming a coupler having an open-end hollow body of a non-conductive crosslinked polyolefin material to allow the couple to have a first minimum inner diameter before heating and a second minimum inner diameter smaller than the first inner minimum diameter after heating. CONSTITUTION: A coupler 10 is made of a polyolefin, for example, polypropylene, polybutylene or the like. The coupler 10 and polyethylene pipes 12, 14 arranged by matching their ends to be bonded integrally with each are assembled, and a heating element 18 is wound in a slot in a saw-tooth outer surface of the coupler 10. A gap 22 exists between an outer surface of the pipe 14 and the minimum inner diameter of the coupler 10 having an inner thread 20. Heating is carried out with the heating element 18, and outer surface temperatures of the coupler 10 and one of the pipes 12, 14 are monitored. The coupler 10 contracts above the pipes 12, 14, and the saw-tooth inner surface of the coupler 10 bites into the outer surfaces of the pipes 12, 14 and mechanically locked with bonding surfaces. |
