| 摘要 |
PURPOSE:To intercept gas quickly and assuredly by coupling a lock mechanism of a valve shaft indirectly to a movable partition wall through a coupling member with a fixed play and releasing the lock mechanism through a toggle joint when pressure exceeds a tolerance limit. CONSTITUTION:When gas passing a cutoff valve device 1 is supplied to gas apparatus through a governor disposed downstream from the cutoff valve device 1, if the governor abnormally increases in secondary pressure because of some cause, a diaphragm 7 is moved up against a spring 14 by pressure in a lower chamber 2b to which secondary pressure is conducted through a line 12. When the diaphragm 7 rises a fixed amount, an adapter 28 starts to move up in one body, and after the adapter 28 is engaged with a needle 9, a pair of coiled springs 33 of a toggle joint 29 are reversed upward. Thus, the needle 9 is moved up at a stroke and each ball 10 is moved inward to release the lock state of a lock mechanism 8, so that a valve body 25 is rapidly closed by a spring 13. |
