| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve device which prevents a backup ring for preventing leakage from an abutment joint of a seal ring from being bitten into an inner peripheral wall of a channel.SOLUTION: A backup ring 7 having a ring disk shape and a seal ring 6 are fit into an annular groove 5 of the seal ring 6. Because the backup ring 7 blocks a gap generated by an abutment joint, a sealing property on total closure can be improved. Furthermore, an engagement part 7a which can be engaged with the inner peripheral surface of the seal ring 6 is disposed at the inner periphery of the backup ring 7. Even if a deviation force is applied to the backup ring 7 with respect to the seal ring 6 at valve opening, the engagement part 7a is engaged with the inner peripheral surface of the seal ring 6, and thereby, the "maximum amount of deviation" by which the backup ring 7 deviates radially with respect to the seal ring 6 is regulated. Accordingly, such a failure that the backup ring 7 is bitten into the inner peripheral wall of the nozzle 3 does not occur and the firm adhesion of the valve can be prevented. |
