Gas Purges; Leak-Test The System; Electrical Supply - Edwards iXH100 Instruction Manual

3.5.2

Gas purges

If you use inert gas purges to dilute dangerous gases to a safe level, ensure that the pump is shut
down if an inert gas supply fails.
Switch on the inert gas purge to remove air from the pump and the exhaust pipeline before the process starts. Switch
off the purge flow at the end of the process only after the remaining flammable gases or vapours have been purged
from the exhaust pipeline.
If liquids that produce flammable vapours could be present in the pump foreline, then the inert gas purge to the dry
pumping system should be left on all the time this liquid is present. Flammable liquids could be present in the foreline
as a result of condensation or may be carried over from the process.
When calculating the flow rate of inert gas required for dilution, consider the maximum flow rate for the flammable
gases/vapours that could occur. For example, if a mass flow controller is being used to supply flammable gases to
the process, you should assume a flow rate for flammable gases that could arise if the mass flow controller is fully
open.
Continually measure the inert gas flow rate: if the flow rate falls below that required, then the flow of flammable
gases or vapours to the pump must be stopped.
3.6

Leak-test the system

Leak test the system after installation and seal any leaks found to prevent leakage of dangerous
substances out of the system and leakage of air into the system.
Note: If you need further information on leak-testing, contact your supplier or Edwards for advice.
3.7

Electrical supply

Ensure that the electrical installation of the pumping system conforms with your local and national
safety requirements. It must be connected to a suitably fused and protected electrical supply and
a suitable earth (ground) point.
This equipment is suitable for Installation Category II as defined in IEC 60664-1. The dry pumping
system must be connected to an isolator that disconnects all current carrying conductors and can
be locked out in the off position (LOTO). The isolator must be in close proximity to the equipment,
within easy reach of the operator and identified as the disconnect device for the equipment.
Isolate the electrical supply before you disconnect the electrical supply cable from the dry
pumping system.
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M561-00-880 Issue C
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