| 摘要 |
<p>PROBLEM TO BE SOLVED: To allow a seal lip 32 tightly adhered to a bellows cap 22 at a movable end of a bellows 20 to certainly prevent introduction of pressure in a pipe into a pressure chamber A, when the bellows 20 extends to a limit extending length by decrease of the pressure in the pipe introduced into the pressure chamber A. SOLUTION: The bellows gap 22 is disposed at the movable end of the bellows 20 separating inside the outer shell 10 the pressure lead-in chamber A and a gas chamber B. In the outer shell 10, a step surface 22b formed on the bellows cap 22 tightly adhered to the seal lip 32 prevents the seal lip 32 of a seal member 30 positioned on the outer periphery of the inner end of a pressure hole C from inverting to the inner peripheral side due to flow pressure of the fluid upon dropping of the pipe pressure and differential pressure between the pressure chamber A and the pressure hole C. A self sealing function of the seal lip 32 certainly shuts between the pressure chamber A and the pressure hole C.</p> |
