| 摘要 |
PURPOSE:To reserve a heat-shrinkable tube under a condition at it is and apply an O-ring effectively by a method wherein the end of the main tube of crosslinking plastic is heated and a wedge is forced into the inside of the tube to expand and correct the ununiform section thereof when the tube of the crosslinking plastic has the ununiform section, thereafter, the end section of the tube is sealed by the O-ring. CONSTITUTION:In case a heat-shrinkable main tube 20 has an ununiform section when a clearance between a fitting 34 and the main tube 20 is to be sealed, the end section of the tube 20 is heated by a burner 50 to a temperature higher than the melting point thereof and the ununiform section is corrected while expanding the tube by forcing a wedge 52 into the tube 20. Generally, the crosslinking polyethylene is not fluidized under a temperature higher than the melting point thereof and shows a rubber elasticity only. When the heated tube is expanded by the wedge 52 to orientate it and is continued to be cooled under a condition that a strain is being provided, the tube is frozen and fixed under a condition at it is due to re-crystallization. Accordingly, an O-ring may be employed effectively. |
