| 摘要 |
PROBLEM TO BE SOLVED: To achieve perfect sealing without making a reaction product attach to a sealing surface by providing a valve disc having a seal in contact with the sealing surface of a valve part of an exhaust pipe and providing in place of the valve disc a protective member in contact with the sealing surface of the valve part of the exhaust pipe. SOLUTION: An exhaust pipe 26 has a valve part 32 having an annular sealing surface 32a. A cutoff valve 30 is provided with a valve disc 34 and a protective member 36. The valve disc 34 and the protective member 36 are the same each other and have an external shape corresponding to the cross-sectional shape of the valve part 32 of the exhaust pipe 26. The valve disc 34 has a solid structure so that it cuts off the flow of a gas and has an annular seal 34a which can be in contact with the sealing surface 32a of the valve part 32 of the exhaust pipe 26. The protective member 36 has an opening 38 to allow the flow of the exhaust gas, and has an annular seal 36a which can be in contact with the sealing surface 32a of the valve part 32 of the exhaust pipe 26. |
