| 摘要 |
PURPOSE: To prevent particles from intruding into a vacuum space by disposing a drive for a valve head outside of the vacuum space. CONSTITUTION: A housing 1 houses an upper 2 and a lower flange connection 3, and gas flowing therein. A valve head 4 connects with a rod 7 and has packing 5 that cooperates with a valve face 6 about the flange connection 3. For movement control or vertical movement of the rod 7 and valve head 4, the housing 1 accommodates a piston 9 movable in a cylinder space 10 in an arrow direction 25 and in the opposite direction. When the pressure space 10 is pressurized, the piston 9 moves in the arrow direction 25 and a transverse bolt 16 slides down along an inclined guide 17 to move the piston 9 up until the valve head 4 is opened. As a spring 12 functions to move the piston 9 slantly downward in the opposite direction to the arrow direction 25, an accordingly compressed cylinder space 10 closes the valve head 4. |
