M588-00-880 Issue E
Page 50 © Edwards Limited 2015. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Operation
Notes: 1. If monitoring the state of the solvent that exits the pump to determine whether the pump is clean take
special care because solvent solution initially exits the pump as steam and then as hot liquid with typical
temperature of 75 °C.
2. The exhausted liquid will never run clear. Exhausted liquid from a ‘clean’ pump has a similar viscosity
to water (not thick and viscous) and is a light rust colour when seen exiting the exhaust.
3. Depending on the application, the solvent flush process may need to be repeated, contact Edwards for
advice.
4. If the pump takes an abnormally long time to draw in fluids, there may be a problem with the high flow
purge and solvent flush kit. A blocked orifice or leaks in the solvent suction pipe or pneumatic gas line
are the most likely causes. Investigate the problem and rectify before continuing to use the solvent flush
procedure. If in doubt, contact Edwards.
Once the DP clean time has elapsed, the dry pumping system will return back to Green Mode/Standby mode settings.
The pump can then be put back on-process.
To stop the solvent flush process whilst it is running, enter the DP Clean menu again using the PDT and select ‘DP
Clean off’. The pneumatic valve will shut, stopping the flow of solvent into the pump. If DP Clean has been configured
to run an inlet purge cycle after the clean cycle, sending a ‘DP Clean off’ command will initiate the purge cycle. To
stop the purge cycle as well, the PDT must be used to select 'DP Clean off' for a second time.
The DP clean procedure can be configured to suit the user’s application, refer to Appendix A2.9.
4.10 Pump speed control and PID
For some applications it is important to be able to adjust the speed of the pump whilst it is on-process, either to a
set speed or to control the speed continuously to maintain a process pressure. The GXS dry pumping system has
capability to run both the dry pump and booster at various speeds whilst on-process and it is possible to configure
these speeds by a number of different methods. Refer to Appendix A2.10 for more information about how to set up
speed control options.
The GXS dry pumping system has a built-in Proportional-Integral-Derivative (PID) controller. When the PID function
is enabled and the pump is on-process, the PID controller continually adjusts the speed of the pump so that a user-
determined pressure is maintained at the chosen pressure sensor.
For more information about enabling and setting up the PID controller, refer to Appendix A2.11.
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