A705-61-880 Issue M
Page 26 © Edwards Limited 2012. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Operation
When the pump has warmed up to its operating temperature, you can start process pumping. In the first 30 seconds
of pumpdown, open the inlet isolation-valve slowly if there is liquid in the inlet pipeline, in order to minimize the
ingress of liquid (entrained in the process gas stream) into the pump.
4.3 Check the purge pressures and flows
Do the following checks immediately after pump start and regularly during pump operation:
1. Check that the pressure of your shaft-seals purge air or nitrogen supply is correct and adjust if necessary
(refer to Section 2.7).
2. If fitted, check that the pressure of your gas-ballast nitrogen supply is correct and adjust if necessary.
3. If necessary, open the gas-ballast flow valve (Figure 1, item 10) to achieve the required gas-ballast flow into
the pump.
4.4 Shut down the pump
Purge the pump before you shut it down. If you do not, process vapours may condense in the pump and corrode
or damage it.
Note: If the pump will be shut down for a long time in an environment where the temperature is close to freezing,
we recommend that you drain the cooling-water from the pump to prevent damage to the pump: refer to
Section 6.1.
1. Isolate the pump-inlet from the process gases.
2. Refer to Figure 1. Purge the pump of contaminants: operate the pump with full gas-ballast (that is, with the
gas-ballast flow valve (10) open) for at least 15 minutes. Alternatively, use one of the following methods:
Operate the pump for at least 45 minutes.
Operate the pump at or close to atmospheric pressure for at least 15 minutes; this is the recommended
method for dusty processes.
Operate the pump with full inlet purge (if fitted) for at least 15 minutes.
3. Close the gas-ballast flow valve (10), or switch off inlet purge (if fitted).
4. Switch off the pump.
5. When the pump has cooled down, turn off the cooling-water supply.
6. Switch off the shaft-seals purge nitrogen supply (if fitted).
Ensure that you do not touch the pump-body when you adjust the gas-ballast flow valve. During
operation, parts of the pump can become hot.
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