| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure for preventing an outer coating layer of a fireproof two-layer pipe joint from being damaged due to deformation such as heat expansion of a joint inner pipe.SOLUTION: In a fireproof two-layer pipe joint 1 in which an outer coating layer 3 made of mortar is molded by injection molding on the outer surface of a synthetic resin-based joint inner pipe, a tabular separator 4 is buried in a screen manner at a position substantially along a weld line of the outer coating layer, and the outer coating layer at the position is in a separation state. The separator comprises a nonflammable or hardly flammable material, is preferably one having heat expansion property and fire resistance property, and may be pushed and buried right after molding of the outer coating layer.SELECTED DRAWING: Figure 4 |
