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Installation
M588-00-880 Issue E
8. Look at the pressure gauge in the inlet pipeline:
If the pressure is increasing, immediately shut down the dry pumping system and contact Edwards.
If the pressure is decreasing continue at Step 9.
9. Visually check the purge gas rotameter on the rear of the pump to ensure purge gas is being delivered to the
pump. Continue to check the rotameter on a regular basis as the dry pumping system is used.
10.After the dry pumping system is commissioned:
To continue to operate the dry pumping system, refer to Section 4.1.
Otherwise, shut down the dry pumping system, refer to Section 4.4.
3.12 Install additional safety equipment
If the total flow rate of purge gas to the dry pumping system is required to be known for safety reasons, suitable
measurement equipment should be fitted in the purge gas supply pipeline. If fitting a rotameter, ensure that it is
suitable for use with the purge gas and that it is correctly calibrated. The rotameter supplied with the pump is not
intended to perform a safety function, it is not calibrated and must be used for indication only.
Ensure that the installation is configured so that it remains safe if there is a failure of the purge gas supply to the
dry pumping system.
If an alarm condition is detected the dry pumping system will shut down automatically. Ensure that the installation
remains safe if the dry pumping system shuts down automatically.
3.13 Purge gas set up
There are two types of gas module used on GXS dry pumping systems, refer to Section 2.4. The gas module
configuration may be adjusted to suit process demands. Contact Edwards service personnel for instruction on how to
access the gas valves menu (by the PDT) and for process-specific recommendations.
For dry pumping systems using the medium duty gas module, there is an adjustable needle valve fitted to the purge
pipe which enables the adjustment of the level of gas ballast to suit the application.
Use the following procedure to adjust the gas ballast:
1. Remove the left hand side panel of the dry pumping system.
2. Identify the adjustable needle valve on the purge pipe (contact Edwards for guidance).
3. Adjust the needle valve until the required flow is met. Note that the rotameter on the rear of the pump
measures total purge gas flow to the dry pumping system, including shaft seal and exhaust purge as well as gas
ballast. The total purge flow is indicated by the position of the centre of the ball in the rotameter. Refer to
Section 2.4 for purge gas flows.
4. Refit the side panel.
If the control system needs to know the total flow rate of purge gas to the dry pumping system for
safety reasons, install suitable measurement equipment in the purge gas supply pipeline.
If the gas purges are used to dilute dangerous gases to a safe level, ensure that the dry pumping
system shuts down if the purge gas supply to the dry pumping system fails.
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