Edwards EXT250 Series, Instruction Manual, Page: 3 / 42

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Contents
B722-01-880 Issue K
Contents
Section Page
1 Introduction ....................................................................................... 1
1.1 Scope and definitions ................................................................................................... 1
1.2 Description ................................................................................................................ 2
1.3 Vent options and vent control ......................................................................................... 5
2 Technical data .................................................................................... 7
2.1 Operating conditions .................................................................................................... 7
2.2 Mechanical data .......................................................................................................... 7
2.3 Performance .............................................................................................................. 8
2.4 Pumping media ..........................................................................................................10
2.4.1 EXT70 and EXT250 pumps without gas purge .......................................................................10
2.4.2 EXT250 pumps with gas purge ........................................................................................10
2.5 Vent gas specification and vent control data ......................................................................11
2.6 Purge gas specification (for EXT250 only) ..........................................................................12
2.7 Cooling-water ...........................................................................................................12
3 Installation ....................................................................................... 15
3.1 Unpack and inspect .....................................................................................................15
3.2 Typical installation .....................................................................................................15
3.3 Connect to the vacuum system .......................................................................................17
3.3.1 Inlet-screen ..............................................................................................................17
3.3.2 Mechanical fixing .......................................................................................................17
3.3.3 Base mounting ...........................................................................................................18
3.3.4 Inlet connection and orientation .....................................................................................18
3.3.5 Backing connection .....................................................................................................19
3.4 Vent-valve connection and control ..................................................................................19
3.5 Purge gas connection (EXT250 only) .................................................................................20
3.5.1 Connect the purge gas .................................................................................................20
3.5.2 Recommended purge gas flow ........................................................................................20
3.6 Electrical installation ..................................................................................................20
3.7 Cooling ...................................................................................................................20
3.7.1 Cooling methods ........................................................................................................21
3.7.2 Forced-air cooling ......................................................................................................21
3.7.3 Water-cooling ...........................................................................................................21
4 Operation ........................................................................................ 23
4.1 Start-up ..................................................................................................................23
4.2 Stand-by ..................................................................................................................23
4.3 Shut-down ................................................................................................................24
4.4 Safety interlocks and control system ................................................................................24
4.5 Bakeout ...................................................................................................................24
5 Maintenance ..................................................................................... 25
5.1 Introduction .............................................................................................................25
5.2 Bearing life ..............................................................................................................25
5.3 Rotor life ................................................................................................................. 25
5.4 Clean the pump .........................................................................................................25
5.5 Fault finding .............................................................................................................26
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