Fastening method of water pipe flange, seal member, and fastening structure of water pipe flange

摘要

PROBLEM TO BE SOLVED: To provide a seal washer capable of restricting droppage of a seal surface from a bolt hole peripheral edge portion without making any large diameter formation of the seal washer.SOLUTION: A seal washer 1 is interposed between seat surfaces 20, 30 of a bolt 2 or a nut 3 and a flange part 40 of a water service pipe 4 and used for tightly sealing a bolt hole 40s formed at the flange part 40. The seal washer 1 has an annular seal member 10 where a seal surface 10f that is used for tightly contacting with a bolt hole peripheral edge portion 40f at an end part becoming a flange part side and having an insertion hole 10s formed by an elastic member to pass through a bolt shaft part 21; and a frame member 11 harder than that of the seal member 10. The peripheral edge part of an insertion hole 10s of the seal member 10 is provided with a fin part 12 protruded from the seal surface 10f in an axial direction under a natural state where any external force may not act and that can be inserted into a clearance between the bolt hole 40s and the bolt shaft part 21.SELECTED DRAWING: Figure 2