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Refer to
clean dry air are suitable purge gases for the dry pumping systems. To use a different
purge gas, contact us.
Check visually that the dial pressure gauge and rotameter (if installed) is not damaged
when installing the dry pumping system.
Note:
Refer to
5.6.1 Flammable/pyrophoric materials
WARNING:
Obey the instructions and take note of any precautions given below to ensure that
pumped gases do not enter their flammable ranges.
When flammable or pyrophoric materials are present within the pump there may be
additional risks that you are responsible for assessing and managing as part of the entire
process system installation. The severity of the risks and the necessary control measures
will depend largely on whether the process system exhaust is in the flammable region, if
this is part of normal operation, or if it might only occur under rare conditions. The
additional risks arise because all dry pumps must be considered as a potential source of
ignition due to the heat of compression, or possibly friction. If ignition occurs then the
following may happen:
▪
High pressures could occur within the pump and may not be contained.
▪
A flame front could travel back up the foreline.
▪
A flame front could travel downstream from the exhaust of the pump.
Industry best practice suggests that the following measures will reduce the risks of
pumping flammable mixtures and pyrophoric materials, but it is your responsibility to
carry out a risk assessment and take appropriate measures:
▪
Do not allow air to enter the equipment.
▪
Ensure that the dry pumping system is leak‑tight.
▪
Ensure that gases in the pump do not enter the flammable range. This may be
achieved by diluting gases in the pump by supplying sufficient inert gas purge. For
example, dilution with nitrogen to below one quarter Lower Explosive Limit (LEL)
or, if that is not practical, to below 60% Limiting Oxidant Concentration (LOC).
▪
The gas module supplied with the pump is not intended to perform a safety
function. You may need to consider adding appropriate measures to monitor the
flow of purge gas (for example, external sensors).
For further information refer to publication number P40040100, applications note
'Pumping Flammable Gases' P4100090 or contact us.
A41870880_A
A41870880_A - Installation
Rear view
on page 12 for the location of the purge gas connection. Nitrogen and
Purge data
on page 18 for the purge gas supply requirements.
Page 38
07/2021 - ©Edwards Limited
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