离心式低温液体泵多采用充气迷宫密封,密封气为(),气体压力要高出低温泵的叶轮背压()左右
A:氧气,0.02MPa
B:仪表空气,0.01MPa
C:仪表空气,0.02MPa
D:高压氮气,0.01MPa
出自:空分操作工