Chapter 15: Vacuum Systems

15.1Introduction3
15.1.1Vacuum equipment related important references3
15.1.2Vacuum Definition3
15.1.2.1Vacuum measurement4
15.1.2.2Industrial vacuum systems5
15.2Vacuum equipment terminology7
15.2.1Suction pressure7
15.2.2Discharge pressure8
15.2.3Capacity of the unit8
15.2.4Air leakage8
15.3Types of Vacuum producing equipment8
15.4Vacuum pump selection10
15.4.1Time required to reach maximum vacuum11
15.4.2Vacuum at high altitudes12
15.4.3Mechanical Vacuum Pumps12
15.4.3.1Gas Transfer Pumps14
15.4.3.2Entrapment (Capture) Vacuum Pump35
15.4.4Jet Pumps and Ejectors39
15.4.4.2Gas-Gas Ejectors42
15.4.4.3Liquid-Gas Ejectors42
15.4.4.4Ejectors for Mass Transfer43
15.4.4.5Steam Ejectors43
15.4.4.6Estimating the Number of Stages54
15.4.4.7Water Vapour Associated with NC Gases54
15.4.4.8Estimation of Steam Consumption of Jets55
15.4.4.9Estimation of Water Consumption of Jets55
15.4.4.10Capacity of Steam Jets for Evacuation57
15.5Air leakage in vacuum vessels60
15.5.1Estimation of air leakage during design stage61
15.6Ejector Efficiency70
15.6.1Staging Ejectors71
15.7.2Ejector Ratings72
15.7.3Effect of MW and Temperature75
15.7.4Discharge Pressure76
15.7.5Changes in Steam Flow76
15.7.6Multi-stage Ejector Design77
15.8Control77
15.9Writing the Specifications80
15.10Process specification sheet85
15.11Go-by P&ID and layout86
15.12Glossary88
15.13References90