For liquid hydrogen system, Helium purge is required after or before nitrogen purge.
For liquid hydrogen system, Helium purge is required after or before nitrogen purge.
对于液氢系统用氮气吹扫之后，还要用氦气吹扫。
For liquid hydrogen system, Helium purge is required after or before nitrogen purge.
对于液氢系统用氮气吹扫之后，还要用氦气吹扫。