When the hand wheel rotation, through the stem-driven plunger in the middle from KER to bottom hole reciprocating movement to complete the valves open and close function.
当手轮旋转，通过阀杆带动柱塞在孔架中间上下往复运动来完成阀门的开启与关闭功能。
2
When the hand wheel rotation, through the stem-driven plunger in the middle from top to bottom hole reciprocating movement to complete the valves open and close function.