| 摘要 |
In a type of combined throttle and trip valve structure, the valve stem has threaded engagement with half nuts; the valve is opened by manual rotation of the stem. Operation of the trip mechanism effects lateral movement of the half nuts out of engagement with the stem and the valve is moved into closed position by spring means. The invention has to do with mechanism to automatically limit the extent of movement of the valve from the valve seat to prevent any jamming of the valve assembly, and to permit the valve to be closed by the spring when the trip mechanism is actuated. |
