空系的英文

empty set

• 空:    leave empty or bla ...
• 系:    system; series
• 抽真空系统:    pumped vacuum syst ...

例句与用法

1. Flanges in the pipeline have to be aligned in parallel and clearance has to be reserved for putting the valve in
   管路法兰必须平行对正并且必须预留空系使阀门能放入。