Edwards EXT555H User manual

B777-00-880
Issue E Original
Instruction Manual
EXT Compound Turbomolecular Pumps:
EXT555H, EXT555Hi and EXT555Hf
Description Item Number
EXT555H / ISO160 B777-01-000
EXT555H / ISO160 (fine) B777-11-000
EXT555H / 160CF B777-02-000
EXT555Hi / ISO160 B777-05-000
EXT555Hf / ISO160 B777-07-000
EXT555Hf / 160CF B777-08-000

Declaration
ofConformity
we, Edwards,
ManorRoyatj
C.awtey,
West
Sussex
RH10
9LW,UK
decLareunderoursoteresponsibititythatthemachine(s)
EXT555HCompoundTurbo-molecutarPumps:
EXT555HEtSO160 NRB-432-000
EXT555HElSO160
(fine) NRB-433-000
EXT555HE160CF NRB-434-000
EXT555HFEtSO160 NRB"435-000
EXT
555HFE
160CF NRB"436-000
towhichthisdectarationretatesisinconformitywiththefotlowingstandard(s)
orothernormativedocument(s)
EN(|SO)12100-2:2003 safetyofMachinery:BasjcConcepts,
GeneratPrjncipLes
forDesign.
TechnicalPrinciptes.
EN
1012-211997 Safety
Requirements,
Vacuum
Pumps.
EN61010-1: 2001 gfety RequirementsforEtectricalEquipment
forMeasurement,
Control
and
LaboratorylJse.'
EN61326:1997 ELectricat
equipment
formeasurement,controtandlaboratory
use
-
+A1:
1998
+A2:
2001 EICrequirements.
t
IndustriaI
tocation,
ClassBemissions
CAN/CSA-C22.2No.61010.1-04 SafetyRequirementsforEtectricatEquipment
forMeasurement,Controt,
AndLaboratoryuse,Part1:GeneraL
Requirements.
r
uLstdNo.
61010-1
(2"d
Edition) Safety RequirementsforEtectricalEquipmentforMeasurement,
Controt,
AndLaboratoryljse,Part1:GeneraL
Requirements.
r
' Thepumps
comptywith EN61010-1: 2001wheninstalledin accordance
with the
instruction
manualsupptied.
r Generic
standardclassdependanton Controller
{see
Controtter
manualfor detaits)
T Pumps
onLycomptywith the CanadianStandardsAuthorityandUnderwriters
Laboratorywhenusedwith EXDC80Vfamityof controllers,EXC100Eand
EXC'100Lcontrolters.
foLtowing
the provisions of
2N6195/EC LowVottageDirective
2O04l108lEC EtectromagneticCompatibitityDirective
98/77/EC MachinerySafetyDirective
6i,-- :.-fE*D----Ze(
4
B.D.Brewster,
Technicall^anager,
BurgessHill Products
cluez,eJ t Ht \--L-
Dote and Ploce
tEowaF EE

© Edwards Limited 2008. All rights reserved. Page i
Edwards and the Edwards logo are trademarks of Edwards Limited.
Contents
B777-00-880 Issue E
Contents
Section Page
1 Introduction .......................................................................................1
1.1 Scope and definitions ................................................................................................... 1
2 Technical Data ....................................................................................3
2.1 General .................................................................................................................... 3
2.2 Pumping media ........................................................................................................... 3
2.2.1 Pumps without gas purge ............................................................................................... 4
2.2.2 Pumps with gas purge ................................................................................................... 4
2.3 Vent gas specification and vent control data ....................................................................... 5
2.4 Purge gas specification ................................................................................................. 5
2.5 Water cooling ............................................................................................................. 5
2.6 Materials exposed to gases pumped .................................................................................. 6
3 Installation .........................................................................................9
3.1 Unpack and inspect ...................................................................................................... 9
3.2 Typical installation .....................................................................................................11
3.3 Connection to the vacuum system ...................................................................................11
3.3.1 Inlet screens (supplied fitted) ........................................................................................11
3.3.2 Inlet connection .........................................................................................................13
3.3.3 Backing connection .....................................................................................................13
3.3.4 Interstage connection (Hi pump variants only) ....................................................................13
3.4 Vent options, vent valve connection and control ..................................................................14
3.5 Purge gas connection ...................................................................................................15
3.5.1 Connect the purge gas .................................................................................................15
3.5.2 Recommended purge gas flow ........................................................................................15
3.6 Electrical installation ..................................................................................................15
3.7 Cooling ...................................................................................................................17
3.7.1 Introduction .............................................................................................................17
3.7.2 Forced air cooling .......................................................................................................17
3.7.3 Water cooling ............................................................................................................17
3.8 Magnetic Fields ..........................................................................................................18
4 Operation ........................................................................................ 19
4.1 Start up ...................................................................................................................19
4.2 Stand-by ..................................................................................................................19
4.3 Shut-down ................................................................................................................19
4.4 Safety interlocks and control system ................................................................................20
4.5 Bakeout (conflat only) .................................................................................................20
5 Maintenance ..................................................................................... 21
5.1 Introduction .............................................................................................................21
5.2 Bearing maintenance ...................................................................................................21
5.3 Clean the pump .........................................................................................................21
5.4 Fault finding .............................................................................................................22
6 Storage and disposal ........................................................................... 25
6.1 Storage ...................................................................................................................25
6.2 Disposal ...................................................................................................................25
dcs/8108/08/08

B777-00-880 Issue E
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Edwards and the Edwards logo are trademarks of Edwards Limited.
Contents
7 Service, spares and accessories .............................................................. 27
7.1 Introduction .............................................................................................................27
7.2 Service ....................................................................................................................27
7.3 Spares .....................................................................................................................27
7.3.1 ISX inlet-screen .........................................................................................................27
7.3.2 Inlet-strainer (EXT555Hi pump only) .................................................................................28
7.3.3 Inlet-flange seals ........................................................................................................28
7.4 Accessories ...............................................................................................................28
7.4.1 Installation ...............................................................................................................28
7.4.2 EXC controller ...........................................................................................................28
7.4.3 Pump-to-controller cable ..............................................................................................30
7.4.4 EXDC drive modules ....................................................................................................30
7.4.5 BX bakeout band (conflat only) .......................................................................................30
7.4.6 FL20K foreline trap .....................................................................................................30
7.4.7 TAV vent-valve and vent-port adaptor ..............................................................................31
7.4.8 ACX air-cooler ...........................................................................................................31
7.4.9 WCX water-cooler ......................................................................................................31
7.4.10 Vibration isolators ......................................................................................................31
7.4.11 PRX purge-restrictor ....................................................................................................32
7.4.12 VRX vent-restrictor .....................................................................................................32
For return of equipment, complete the HS Forms at the end of this manual.
Illustrations
Figure Page
1 Typical pumping system ...............................................................................................10
2 Diagram of inlet screen - remove screws 'A' in order to remove the inlet screen.
Do not remove screws 'B' 12
3 Maximum rate of pressure rise when venting ......................................................................14
4 Dimensions and features of EXT555H pumps .......................................................................16
5 Installation of EXT555H optional accessories and spares .........................................................29

© Edwards Limited 2008. All rights reserved. Page iii
Edwards and the Edwards logo are trademarks of Edwards Limited.
Contents
B777-00-880 Issue E
Tables
Table Page
1 General information ..................................................................................................... 3
2 Vent gas and vent control data ........................................................................................ 5
3 Purge gas specification ................................................................................................. 5
4 Cooling water specification ............................................................................................ 5
5 Technical data ........................................................................................................... 6
6 List of items supplied ................................................................................................... 9
7 Vent restrictor orifice diameter (with atmospheric pressure at the inlet) ....................................15
8 Fault finding .............................................................................................................22
9 ISX inlet-screen .........................................................................................................27
10 Inlet-strainer (EXT555Hi pump only) .................................................................................28
11 Inlet-flange seals ........................................................................................................28
12 EXC controller ...........................................................................................................28
13 Pump-to-controller cable ..............................................................................................30
14 EXDC drive modules ....................................................................................................30
15 BX bakeout band ........................................................................................................30
16 FL20K foreline trap .....................................................................................................30
17 TAV vent-valve and vent-port adaptor ..............................................................................31
18 ACX air-cooler ...........................................................................................................31
19 WCX water-cooler ......................................................................................................31
20 Vibration isolators ......................................................................................................31
21 PRX purge-restrictor ....................................................................................................32
22 VRX vent-restrictor .....................................................................................................32
Associated publications
Publication title Publication number
EXC120/120E/300/300M Turbomolecular Pump Controllers D396-14-880
EXC250E/250L Turbomolecular Pump Controllers D396-36-880
EXDC Turbomolecular Pump Drive Modules D396-40-880

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B777-00-880 Issue E
Page iv © Edwards Limited 2008. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.

© Edwards Limited 2008. All rights reserved. Page 1
Edwards and the Edwards logo are trademarks of Edwards Limited.
Introduction
B777-00-880 Issue E
1Introduction
1.1 Scope and definitions
This manual provides installation, operation, maintenance and storage instructions for the Edwards EXT555H
compound turbo-molecular pumps. Please read and follow all the instructions in this manual.
The EXT555H pump is designed for use with a Edwards EXC or EXDC controller. Read this manual and the instruction
manual supplied with your controller before you attempt to install or operate the equipment. The controller manual
contains details of electrical installation.
Important safety information in this manual is highlighted as WARNING and CAUTION instructions. Please obey these
instructions. The use of warnings and cautions is defined below.
CAUTION
Cautions are given where failure to observe the instruction could result in damage to the equipment, associated
equipment or process.
In accordance with the recommendations of EN61010, the following warning symbols may appear on the pump or its
accessories:
The units used throughout this manual conform to the SI system of units of measurement. Also, throughout this
manual, wherever flow rates are specified, the abbreviation 'sccm' is used to mean standard cm3min-1: this is a flow
of 1 cm3min-1 at an ambient temperature of 0 °C and a pressure of 1013 mbar (1.013 x 105Pa).
WARNING
Warnings are given where failure to observe the instruction could result in injury or death to
people.
Warning - refer to accompanying documentation.
Warning - risk of electric shock.
Warning - hot surfaces.
Warning - Large attractive forces will be experienced when the pump is subjected to magnetic fields.

B777-00-880 Issue E
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This page has been intentionally left blank.

© Edwards Limited 2008. All rights reserved. Page 3
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Technical Data
B777-00-880 Issue E
2TechnicalData
2.1 General
2.2 Pumping media
CAUTION
Do not use an EXT555H pump to pump gases containing more than 20% oxygen unless a bearing purge is applied
as stated in Section 2. If you do the lubricant will be damaged and the pump will fail prematurely.
Table 1 - General information
General items Reference data
Performance See Table 5
Dimensions and features See Figure 4
Maximum inlet flange temperature 80 °C
Maximum magnetic field
EXT555H DN160CF 3 mT horizontal, 5 mT vertical
EXT555H ISO160 2.5 mT horizontal, 5 mT vertical
EXT555HF ISO and CF variants 50mT in any orientation
Installation category EN61010 part 1, category 1
Pollution degree CAN/CSA, UL, EN61010 part 1, category 2
Equipment type Fixed equipment, for indoor use only
Operating altitude up to 2000 m
Ambient temperature 5 °C - 35 °C (air cooled)
5 °C - 40 °C (water cooled)
Relative humidity 10 – 90% non condensing
Electrical supply 80 V
WARNING
Vent dangerous gases and gas mixtures safely. Do not expose people to these gases.
WARNING
Do not use EXT555H pumps to pump explosive gas mixtures as the pumps are not suitable
for this purpose.
WARNING
On an Hi variant, gas pumped through the interstage port will mix with gas pumped through
the pump inlet. Ensure that the gases will not react or combine to form dangerous gases
and substances.

B777-00-880 Issue E
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Technical Data
CAUTION
Do not use the EXT555H pump to pump mercury vapour, and do not allow mercury to come into contact with
the pump. If you do, the rotor may corrode and fail.
Note: Concentrations of gases may be modified by the compression of the pump.
2.2.1 Pumps without gas purge
The pumps are designed to pump the following residual gases normally used in high vacuum systems:
zair
znitrogen
zcarbon dioxide
zcarbon monoxide
zkrypton
zhelium
zneon
zargon
zhydrogen
zethane
zpropane
zbutane
zmethane
You can use the pumps to pump oxygen and water vapour subject to the following conditions:
zOxygen
The oxygen concentration must be less than 20% by volume unless a bearing purge is applied as detailed in
Section 2.2.2.
zWater vapour
You must ensure that vapour does not condense inside the pump - refer to Section 3.7.3.
If you wish to pump a gas not previously listed, contact your supplier for advice. If you do not contact your supplier
you may invalidate the warranty on the pump.
The pumps are not suitable for pumping aggressive or corrosive gases.
2.2.2 Pumps with gas purge
When purged with an inert gas the pumps can be used to pump oxygen in concentrations above 20% by volume.

© Edwards Limited 2008. All rights reserved. Page 5
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Technical Data
B777-00-880 Issue E
2.3 Vent gas specification and vent control data
Although the pump may be vented to atmosphere, relatively high air humidity may greatly increase the subsequent
pump-down time. To reduce pump-down times you should vent the pump with dry, clean gases.
2.4 Purge gas specification
2.5 Water cooling
The following water cooling specification corresponds to a typical high quality drinking water specification. Check
with your water supply authority if you are in doubt about the quality of your supply.
Table 2 - Vent gas and vent control data
Vent gas system items Reference data
Vent gas Dry air, nitrogen, argon or other inert gases
Maximum dew point at atmospheric pressure -22 °C
Maximum size of particulate 1 micron
Maximum concentration of oil 0.1 parts per million
Time for rotational speed to reach 50% >15 seconds
Maximum allowed rate of pressure rise see Figure 3
Table 3 - Purge gas specification
Purge gas system items Reference data
Purge gas Dry nitrogen, argon or other inert gases
Maximum dew point at atmospheric pressure -22 °C
Maximum size of particulates 1 micron
Maximum concentration of oil 0.1 parts per million
Allowable purge gas flow (when required) 20 to 150 sccm (0.33 to 2.48 mbar l s-1,
33 to 248 Pa l s-1)
Recommended purge gas flow 25 sccm (0.42 mbar l s-1, 42 Pa l s-1)
Maximum allowable purge gas supply pressure 2 bar gauge (29 psig, 3 x 105Pa)
Table 4 - Cooling water specification
Cooling water system items Reference data
Quality Mechanically clean and optically with no deposits
or turbidity
pH value 6.0 to 8.0
Maximum calcium carbonate concentration 75 parts per million
Maximum chloride concentration 100 parts per million
Minimum oxygen concentration 4 parts per million
Recommended water cooling flow rate (at 15 °C) 15 l hr-1
Water temperature See Table 5
Maximum water pressure 5 bar (gauge), 73.5 psig, 6 x 105Pa
Materials exposed to cooling water Copper, brass, braise

B777-00-880 Issue E
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Technical Data
2.6 Materials exposed to gases pumped
The following materials and component types are exposed to the gases pumped: aluminium alloys, stainless steels,
fluoroelastomer and nitrile 'O' rings, hydrocarbon lubricant, rare earth magnets, silicon nitride, phenolic resin and
carbon fibre epoxy resin.
Table 5 - Technical data
Parameter EXT555H Notes
Mass EXT555H ISO160 13.4 kg
Mass EXT555H DN160CF 21.2 kg
Main inlet flange DN160ISO-K/DN160CF
Outlet flange DN25NW
Interstage port (Hi variants) DN25NW
Vent port 1/8 inch BSP
Purge port 1/8 inch BSP
Inlet pumping speed *
N2540 l s-1
He 580 l s-1
H2500 l s-1
Ar 510 l s-1
Interstage pumping speed *
N28 l s-1
He 6 l s-1
H28 l s-1
Ar 10 l s-1
Inlet compression ratio †
N2>1010 Pb < 20 mbar
He 108Pb < 12 mbar
H2106Pb < 7 mbar
Ar >1010 Pb < 20 mbar
Critical backing pressure ‡
N2> 20 mbar
He 20 mbar
H29 mbar
Ar > 20 mbar
Ultimate pressure
CF <10-10 mbar
ISO <2 x 10-9 mbar
Minimum backing pump
displacement 12 m3 h-1
Recommended backing pump RV12

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Technical Data
B777-00-880 Issue E
Maximum continuous inlet pressure
(light gas pumping) **
Forced air cooled, 30 °C ambient 1 x 10-3 mbar
Forced air cooled, 35 °C ambient 5 x 10-4 mbar
Water cooling at 15 °C 2 x 10-3 mbar
Maximum continuous inlet pressure
(argon pumping) **
Forced air cooled, 30 °C ambient 2 x 10-4 mbar
Forced air cooled, 35 °C ambient 2 x 10-4 mbar
Water cooling at 15 °C 1 x 10-3 mbar Water cooling while pumping high
concentrations of argon is not
recommended
Maximum continuous backing
pressure (light gas pumping) **
Forced air cooled, 30 °C ambient 12 mbar
Forced air cooled, 35 °C ambient 7.5 mbar
Water cooling at 15 °C 15 mbar
Maximum continuous backing
pressure (argon) **
Forced air cooled, 30 °C ambient 5 mbar
Forced air cooled, 35 °C ambient 3.5 mbar
Water cooling at 15 °C 8 mbar Water cooling while pumping high
concentrations of argon is not
recommended
Operating attitude Any
Nominal rotational speed 50000 rpm
Start time to 90% speed:
EXC250 < 8 minutes
EXC300 < 8 minutes
EXDC160 < 8 minutes
Cooling method forced air / water
Ambient air temperature for forced
air cooling 0 °C - 35 °C
Minimum cooling water flow rate
(water at 15 °C) 15 l h-1
Water temperature 10 °C - 20 °C
Noise level at 1 metre <60 dBA
Recommended controllers EXC250, EXC300, EXDC160
Quiescent power consumption 35 W
*Pumping speeds are without inlet screen or inlet strainer (EXT555Hi)
The coarse and fine inlet screens/strainers reduce the pumping speed by 11% and 17% respectively.
†Pb = backing pressure
‡Pumping speed has dropped by 10%
** Above this pressure the rotational speed of the pump drops below nominal and light gases refer to those
with a rmm <28amu
Table 5 - Technical data (continued)
Parameter EXT555H Notes

B777-00-880 Issue E
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© Edwards Limited 2008. All rights reserved. Page 9
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Installation
B777-00-880 Issue E
3 Installation
3.1 Unpack and inspect
CAUTION
Do not damage the envelope surface of the HF variant as this may cause corrosion and a reduction in
performance. In this event the pump must be returned to your nearest service centre.
Take care when you unpack the pump to avoid excessive shocks which could damage the bearings and reduce the life
of the pump. The pump is supplied with the inlet and the outlet sealed to prevent entry of dust and vapour. Do not
remove these seals until you are ready to install the pump on your vacuum system.
Remove all the outer cardboard packaging and check the pump. If the pump is damaged, notify your supplier and
carrier in writing within three days; state the item number of the pump together with your order number and your
supplier's invoice number. Retain all the packing materials for inspection. Do not use the pump if it is damaged.
Check that your package contains the items listed in Table 6. If any of these items is missing, notify your supplier in
writing within three days.
If the pump is not to be used immediately, store the pump in suitable conditions as described in Section 6.1.
It is advised that you retain all packing materials for use should you return the pump for service.
WARNING
The EXT555H DN160CF pump variant weighs 21 kg. Take care when handling the pump and ensure
that you grip it firmly by the inlet flange when manoeuvring it.
Table 6 - List of items supplied
Qty Description
1 EXT555H turbomolecular pump
1Inletscreen(fitted)
1 Inlet seal (trapped 'O' ring, co-seal or copper compression gasket)
1 Inlet strainer (EXT555Hi only, fitted in the interstage port)

B777-00-880 Issue E
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Edwards and the Edwards logo are trademarks of Edwards Limited.
Installation
Figure 1 - Typical pumping system
1. Alternative position for
vent-valve
2. Vacuum system
3. High-vacuum gauge
4. Inlet-screen
5. EXT pump
6. Backing valve
7. Vacuum gauge
8. Flexible bellows
9. Foreline trap
10.Rotary backing pump
11.Mist filter
12.Cooling water connectors
13.EXC controller
14.Air cooler
15.PRX10 purge restrictor
16.Regulated purge gas supply
17.Vent-valve

© Edwards Limited 2008. All rights reserved. Page 11
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Installation
B777-00-880 Issue E
3.2 Typical installation
A typical pump system with an EXT555H pump is shown in Figure 1.
The accessories available for the EXT555H pump are detailed in Section 7.4. The accessories are shown in Figure 5.
3.3 Connection to the vacuum system
Carefully remove the pump from packaging media and connect to the vacuum system.
3.3.1 Inlet screens (supplied fitted)
CAUTION
Removal of inlet screens could allow debris to fall into the pump, which could cause serious damage to the pump.
Do not remove inlet screens unless you can be sure that there is no danger that debris can fall into the pump. If the
inlet screens are removed, the pumping speed through the inlet will increase by 11% for a coarse and 17% for a
fine screen.
To remove the inlet screen, undo the three screws ('A') which hold it down (Figure 2). If you need to replace the inlet
screen, do so by undoing these screws, changing the inlet screen, and replacing the screws. Ensure that screws are
firmly tightened.
CAUTION
Do not remove the three screws which retain the locking plate ('B' in Figure 3). If you do so the pump settings
may change and the pump may cease to operate or have a shortened life.
WARNING
Install the pump on the vacuum system before you connect the controller to the power supply.
This will ensure that the pump cannot operate and injure people during installation.
WARNING
Removal of inlet screens will expose people to the risk of injury from sharp edges.

B777-00-880 Issue E
Page 12 © Edwards Limited 2008. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Installation
Figure 2 - Diagram of inlet screen - remove screws 'A' in order to remove the inlet screen.
Do not remove screws 'B'

© Edwards Limited 2008. All rights reserved. Page 13
Edwards and the Edwards logo are trademarks of Edwards Limited.
Installation
B777-00-880 Issue E
3.3.2 Inlet connection
Ensure that the EXT555H pump is securely fixed to the vacuum system following the instructions below.
Make sure that the pump inlet and all components fitted to the pump inlet are clean and dust free. If the pump inlet
is not kept clean the pump down time may be increased.
Use the vacuum seal provided with the pump.
If you are using an EXT555H ISO160 pump, connect it to the vacuum system using an ISO160 rotatable flange with a
full complement of bolts. Alternatively use at least 8 claw clamps.
If you are using an EXT555H DN160CF, use a full complement of 20 M8 bolts to attach the pump to your
vacuum system.
If the inlet flange of the EXT555H is not connected to a rigid, firmly fixed vacuum system, ensure that the base of
the pump is fixed to a firm support. Remove the four feet and secure the pump using eight M8 screws through the
tapped fixing holes in the base of the pump. If you are using a WCX555 water cooling accessory, mount through the
cooling plate into the tapped holes on the base of the pump.
If the pump inlet is connected to the vacuum system using a vibration isolator, use the tapped fixing holes in the base
of the pump to secure the pump to a firm support as described above. Alternatively, fit suitable restraints to prevent
movement of the pump and fracture of the vibration isolator in the unlikely event of a seizure of the pump rotor.
The pump can be mounted in any orientation. If it is mounted off-vertical, ensure that the backing port points
downwards to reduce the risk of contamination from backing pump oil.
3.3.3 Backing connection
Use suitable vacuum tubing and connectors to connect the NW flange of the backing port to your backing pump. If
necessary use flexible pipe or bellows to reduce the transmission of vibration from the backing pump to the
EXT555H pump.
We recommend that you use a Edwards RV backing pump. The minimum size of the backing pump required is given
in Table 5. You may have to use a larger backing pump if you run the pump at a high inlet pressure or high throughput,
or if you purge the pump.
CAUTION
If you back the EXT555H pump with the interstage of another turbomolecular pump, make sure that the backing
pressure does not fall below 5 x 10-4 mbar (5 x 10-2 Pa). Lower backing pressures will increase the evaporation
rate of the lubricant and so will reduce the life of the bearings.
3.3.4 Interstage connection (Hi pump variants only)
Use suitable vacuum tube and connectors to connect the interstage port to your vacuum system or to the outlet
flange of another turbomolecular pump. Leave the inlet strainer in the interstage port unless you are sure that debris
cannot be drawn into the interstage port.
WARNING
Ensure that the EXT555H pump is securely fixed to the vacuum system following the instructions
below. If you do not, and the pump seizes, the stored energy of the rotor can cause rapid
movement of the pump, which may cause injury to people and further damage to equipment.

B777-00-880 Issue E
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Edwards and the Edwards logo are trademarks of Edwards Limited.
Installation
3.4 Vent options, vent valve connection and control
To maintain the cleanliness of your vacuum system we recommend that, whenever you switch the pump off, you vent
the pump or the vacuum system when the speed of the EXT555H pump is between full rotational speed and 50% of
full rotational speed. At and above 50% of full rotational speed the rotor spins fast enough to suppress any
hydrocarbon oil from your backing pump. Venting may be accomplished by one of the following methods:
zUse a TAV5 or TAV6 solenoid vent valve accessory (see Section 7) in place of the manual vent valve.
zUse a TAV5 or TAV6 solenoid vent valve connected to a convenient flange on your vacuum system.
zUse an alternative valve connected to your vacuum system.
The maximum rate of pressure rise is given in Figure 3.
Figure 3 - Maximum rate of pressure rise when venting
CAUTION
If you vent the pump when it is at full rotational speed and the rate of pressure rise is too high the pump bearing
life may be reduced.
When using the manual vent valve supplied you must only open the vent valve when the rotational speed of the
EXT555H pump has fallen to 50% of full rotational speed.