Estimation of minimum power consumption and pumps cost for the differential pumping system

The air-to-air vacuum sealing device is composed of evacuated multi stages and the differential pumping system to maintain the pressure of the deposition chamber at 5 10ÿ2 Pa. The differential pumping system is adopted to evacuate the deposition chamber with minimum power consumption and pumps cost through the estimation of air ¯ow rate and pressure. The air ¯ow rate of each stage (Q) and pressure (P) is calculated accurately in region of viscos ¯ow, viscos slip ¯ow, transient ¯ow, molecular ¯ow based on the experimental results. # 2001 Elsevier Science B.V. All rights reserved.