COUPLING STRUCTURE OF AL ALLOY PIPE HAVING EXCELLENT AIRTIGHT DURABILITY

摘要

PURPOSE: To provide the coupling structure of an Al allow pipe which is constituted to hold airtightness of coupling fastening for a long period and have excellent durability. CONSTITUTION: In a pipe coupling structure wherein an O-ring 8 is nipped between the bulge processing part 5 of an Al alloy pipe and a first coupling member 2 joined with an entrance piping 1 on the heat-exchanger side. A second coupling member 6 is pressed against a bulge processing part from the opposite side to the bulge processing part and the second coupling member and the first coupling member are intercoupled, a thermoplastic resin layer 7 with a thickness of 50-500μm is formed on the O-ring side of the bulge processing part of at least the Al alloy pipe and the thermoplastic resin layer and the O-ring are adhered together.