Edwards EXT255H Series - Default Chapter; Table of Contents

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Contents
B722-20-880 Issue D
Contents
Section Page
1 Introduction ....................................................................................... 1
1.1 Scope and definitions ................................................................................................... 1
1.2 General description ..................................................................................................... 2
1.3 Vent options and vent control ......................................................................................... 2
2 Technical data .................................................................................... 5
2.1 General .................................................................................................................... 5
2.2 Pumping media ........................................................................................................... 5
2.2.1 Pumps without gas purge ............................................................................................... 6
2.2.2 Pumps with gas purge (EXT255H 24 V and EXT255Hi 24 V only) .................................................. 6
2.3 Vent gas specification and vent control data ....................................................................... 6
2.4 Purge gas specification (EXT255H 24 V and EXT255Hi 24 V only) ................................................ 9
2.5 Cooling-water ............................................................................................................ 9
2.6 Materials exposed to gases pumped .................................................................................. 9
3 Installation ....................................................................................... 15
3.1 Unpack and inspect .....................................................................................................15
3.2 Typical installation .....................................................................................................15
3.3 Connect to the vacuum system .......................................................................................18
3.3.1 Inlet-screen ..............................................................................................................18
3.3.2 Mechanical fixing .......................................................................................................18
3.3.3 Base mounting ...........................................................................................................19
3.3.4 Inlet connection and orientation .....................................................................................19
3.3.5 Backing connection .....................................................................................................20
3.3.6 Interstage connection ((EXT70Hi 24 V and EXT255Hi 24 V only) ................................................ 20
3.4 Vent-valve connection and control .................................................................................. 20
3.5 Purge gas connection (EXT255H 24 V and EXT255Hi 24 V only) ..................................................21
3.5.1 Connect the purge gas .................................................................................................21
3.5.2 Recommended purge gas flow ........................................................................................21
3.6 Electrical installation ..................................................................................................21
3.6.1 EXDC drive module .....................................................................................................21
3.6.2 Earth (ground) connections ...........................................................................................22
3.7 Cooling ...................................................................................................................22
3.7.1 Introduction .............................................................................................................22
3.7.2 Forced-air cooling ......................................................................................................22
3.7.3 Water-cooling ...........................................................................................................23
4 Operation ........................................................................................ 25
4.1 Start-up ..................................................................................................................25
4.2 Shut-down ................................................................................................................25
4.3 Shut-down due to pump under or over-speed ......................................................................26
4.4 Bakeout ...................................................................................................................26
5 Maintenance ..................................................................................... 27
5.1 Introduction .............................................................................................................27
5.2 Bearing life ..............................................................................................................27
5.3 Rotor life .................................................................................................................27
5.4 Clean the pump .........................................................................................................27
5.5 Fault finding .............................................................................................................28
ITR 22317