NIB-SEAL on sweat ball valves are shipped unassembled.

在焊接球阀上，NIB-SEAL在装时处于未组装状态。

The condensability of liquid,the Westphal's effect and the continuous flow condition are not only comprehensively considered,but also the dynamic property of the ball valve being established.

结合现场试验,线电机采油泵动特性,综合考体的可压缩性、魏氏效应、体连续流动条件和球阀的动力特性,建立线电机采油泵球阀动规律的精确动微分方程组。