| 摘要 |
To join two tubular parts (10) made of plastic, such as polyvinylidene fluoride, polypropylene, polyethylene or similar, and having the same diameter, undercuts (14) are made in the abutting surfaces (12, 13) and said surfaces are then heated to a uniform depth in the area of the abutting surfaces. When the two surfaces are subsequently joined and consolidated, there is practically no passage of softened material into the inner space area of the tubular parts, due to the undercuts. This is of particular advantage when forming the inner surface of the bonded parts to encourage flow. A tool for said heating and for softening or melting open the tube walls in the area of said abutting surfaces is fitted with rings (21-24) of polytetrafluorethylene, having surfaces corresponding to the undercut or recess, enabling said softening of the tube wall to a uniform depth to be achieved in an axial direction. |
