At this point the upper stem has lost contact with the diaphragms. The valve should be opened to this point but not back seated.
在此时，上阀杆已经失去了同横膈膜的接触。阀门应该开启到这一点，但不能反向固定。
A step on the stem has now been back-seated against the upper portion of the valve body.
阀杆上的台阶现在已经坐落在阀体的上面部分上。
A step on the stem has now been back-seated against the upper portion of the valve body.
阀杆上的台阶现在已经坐落在阀体的上面部分上。
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