Handwheel torque or actuator force provides positive seat-knife closure. During closure, the stem slides down pushing the knife into contact with the two bottom lugs.

• 手轮扭矩或执行机构扭力是正阀座-闸刀关闭的动力源。在关闭期间，阀杆向下滑动推动闸刀向下抵住两个底部凸耳。