求助一句话的理解? Slag tapping is in "manual-run" mode, all burner double-block and vent valves are powered-up and shut with their vents open with the exception of the nitrogen double-block and vent system (YV 4420, YV 4430 & YV 4440) which is open, as is the main air/nitrogen flow control valve, FC4380. 请问这句话应该怎么理解?? 查看更多6个回答 . 1人已关注