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A301-51-880 Issue T
The EH1200, EH2600 and EH4200 ATEX compliant EH pumps that have a T160 temperature classification are
suitable for pumping flammable materials that have an auto-ignition temperature greater than 160
The EH1200, EH2600 and EH4200 ATEX compliant pumps that have a T4 classification are suitable for
o
pumping flammable materials that have an auto-ignition temperature greater than 135
C.
Refer to
Section 2
of this manual for the necessary EH pump operating conditions, to the ATEX Instruction Manual,
and to your system manual for specific details of the system in which the EH pump is fitted.
1.3.4
Hydrokinetic drive/gearbox purge
WARNING
When using the EH ATEX compliant booster in either a Edwards ATEX compliant system or in your
own certified ATEX vacuum pumping system you must ensure that the gearbox purge is connected
to your booster and the Nitrogen supply is guaranteed. Please refer to
Section 2.7
for operating
conditions.
A pipeline connector is provided on the oil filler of the hydrokinetic drive/gearbox of all of the chemical and ATEX
compliant EH pumps. You can connect a suitable purge gas supply to this connector, to provide for purge of the
hydrokinetic drive with nitrogen at positive pressure. This will purge the shaft-seals, and prevent the entry of
corrosive or toxic vapours into the hydrokinetic drive and gear-cover.
A fixed restrictor in the connector ensures that the correct amount of nitrogen is allowed to flow into the
hydrokinetic drive/gearbox.
1.3.5
After-cooler
On the EH2600C, EH2600T3X, EH2600T160/T4X, EH4200C, EH4200T3X, EH4200T160/T4X chemical and ATEX
compliant EH pumps, the nickel-plated after-cooler is resistant to corrosive vapours which may condense on it during
pump operation (depending on the application).
1.3.6
Normal operation
WARNING
The ATEX compliant EH pumps rely on the principle of constructional safety to pump flammable
gases and vapours safely. Process deposits (which could form due to condensation of process
vapours) do not normally occur in booster pumps. However, to conform with constructional safety
requirements, it is your responsibility to ensure that process deposits do not occur in the ATEX
compliant EH pump (see below).
WARNING
The ATEX compliant EH pumps rely on the principle of constructional safety to pump flammable
gases and vapours safely. You must protect the ATEX compliant EH pump from the ingress of
particles that could cause an ignition of flammable gas or vapour in the pump. If particles could
enter the ATEX compliant EH pump during system commissioning, you must fit a suitable inlet filter
or screen, which you should then remove before process operation (refer to
Section
3.9).
The ATEX compliant EH pumps rely on the pump's constructional safety for the safe pumping of flammable materials.
In normal operation, as defined by this manual, the ATEX compliant EH pumps are safe for the pumping of flammable
materials where there is no risk that the build-up of process deposits could reduce the operating clearances of the
pump mechanism, and so cause a potential ignition hazard.
Where there is no such risk, the ATEX compliant EH pumps can be used to pump flammable materials from gas group
IIA, IIB and IIC within the normal parameter defined in this manual.
© Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
A301-51-880 Issue T
2
Technical Data
2.1
Operating and storage conditions
Notes:
1. For operation between -20 ºC and 5 ºC, we recommend that the EH pump is operated continuously
except when shut-down is necessary for maintenance purposes. Note also the cooling-water
requirements given in
Section
2.8.
2. Because of the flexibility of the hydrokinetic drives, there is a wide range of backing pumps which are
suitable for use with the EH Mechanical Booster pumps. However, note the restrictions for chemical and
ATEX compliant EH pump critical backing pressure given in
Section
2.2. If necessary, contact Edwards
for advice.
Table 1 - Operating and storage conditions
Ambient operating temperature range
-20 to 40 ºC
Ambient storage temperature range
-20 to 80 ºC
Maximum ambient operating humidity
90% RH
Protection degree (as defined by IEC 529)
IP44
Recommended backing pumps
See Note above
2.2
Critical backing pressure
WARNING
For ATEX compliant EH pumps, which have been sold to you on their own and not as part of an
approved Edwards ATEX system (which are fitted with flameproof motors), the outlet pressure of
the ATEX compliant EH pump must not exceed the critical backing pressure at zero flow, as
specified below. If this critical pressure is exceeded, internal temperatures in the ATEX compliant
EH pump may exceed the temperature classification (refer to
Section
1.3.3) and render it invalid.
This can result in an internal ignition of the pumped gases/vapours.
If you fit an isolation valve between the ATEX compliant EH pump and the backing pump, you must
interlock the operation of the valve with the operation of the ATEX compliant EH pump, so that
closure of the valve results in shut-down of the ATEX compliant EH pump.
If this critical backing pressure is exceeded, the pump rotors have to do additional compressive work against the
backing pressure, which can cause the rotor temperature to exceed the temperature classification limits, as there is
no flow of cooling gas through the pump. The critical backing pressure at zero flow is equivalent to the ultimate
pressure of the backing pump, when an isolation valve upstream of the ATEX compliant EH pump is closed.
The critical backing pressure at zero flow for your EH booster pump depends on the temperature classification (please
refer to
Section 1.3.3
Temperature Classification) of the mechanical booster pump. The following critical backing
pressures apply for different temperature classifications for standalone boosters which haven't been sold as part of
an approved Edwards ATEX system:
Table 2 - Temperature classifications
Temperature Classification
Critical backing pressure [mbar]
T3
40
T160
30
T4
20
If you want to use the EH booster outside the critical backing pressure specified above, please contact Edwards for
advice.
© Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
o
C.
Page 7
Page 9
A301-51-880 Issue T
1.3.7
Abnormal operation
WARNING
Misuse of the chemical and ATEX compliant EH pump as described below is strictly prohibited:
Pumping gases with temperatures greater than the system temperature classification (see
Section
Pumping hydrocarbon oxides.
Pumping pyrophoric gases.
Pumping gases that tend to self-decompose, or that are chemically unstable.
Pumping peroxides or oxygen enriched atmospheres with ATEX certified pumps. For non-ATEX applications
PFPE versions of the pumps can be offered for oxygen enriched atmospheres and peroxides.
Use of the chemical and ATEX compliant EH pump with materials which have auto-ignition temperatures
below the defined temperature rating of the chemical EH pump.
Pumping of, or use of the ATEX compliant EH pump in the presence of, explosive dust atmospheres.
Use of the ATEX compliant EH pump in ambient conditions other than those specified in
Section
2.1.
1.3.8
Electrostatic charges
Pure gas doesn't create electrostatic charges. There is a danger of electrostatic charges when the gas pumped
contains droplets or particles.
Always ensure that the pump is earthed so there is no danger of igniting flammable gases due to electrostatic
discharges.
Page 8
© Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
A301-51-880 Issue T
In addition, the pressure ratio between the EH mechanical booster pump and the backing pump has to be kept within
certain limits to ensure that the temperature limits are not exceeded.
The following general pressure ratio figures apply in relation to the temperature class of your vacuum pumping
system:
Table 3 - Pressure ratio figures
Pressure ratio at duty point
Temperature class of vacuum system
3:1
T3
2.5: 1
T160
2:1
T4
If you want to use your booster outside these limits, please contact Edwards for advice.
The following tables show possible combinations of Edwards EH mechanical booster pump with Edwards DPS Chemical
Dry pump.These systems are Edwards approved ATEX systems.
Please note that the following tables refer to 50 Hz operation only.
For Edwards EH mechanical booster/ DPS dry pump combinations depending on temperature class of the system:
Table 4 - DPS dry pump and EH mechanical booster pump combinations for T3
Dry Pump
Booster Pump
DPS 80
DPS 160
DPS 250
DPS400
EH250 T3
EH500 T3
EH1200 T3
EH2600 T3
*
*
EH4200 T3
*
*
*
Do not require extra protection
*
Consult Edwards for advice
Table 5 - DPS dry pump and EH mechanical booster pump combinations for T160
Dry Pump
Booster Pump
DPS 80
DPS 160
DPS 250
DPS400
EH250 T160
EH500 T160
EH1200 T160
EH 2600 T160
*
*
EH 4200 T160
*
*
*
Do not require extra protection
*
Consult Edwards for advice
Page 10
© Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
1.3.3).
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