Emerson 540VDC manual Vacuum System, Vacuum system operation

System Overview

5.1.11Vacuum System

During manufacture, the vacuum chambers are evacuated and baked to remove water vapor. The vac- uum system is then permanently sealed off to prevent any air entering the system and to remove the possibility of accidental loss of vacuum. The Liebert FS does not require an external vacuum pump to maintain a suitable vacuum level; the vacuum system instead relies on absorbers to maintain a rough vacuum within the upper chamber. A zero-maintenance molecular drag pump acts with the flywheel shaft to maintain a high-vacuum in the lower chamber, as shown in Figure 41. Vacuum levels of much less than 100 microTorr (10-7 atmosphere) are maintained in the lower chamber. The absorber material only needs to be recharged or changed, once every 15 years.

Figure 41 Vacuum system operation

Air and Water Vapor

Upper Chamber

Molecular Drag Pump

Rotating Shaft

Lower Chamber

40	DISCONTINUED
	PRODUCT