Table of Contents
Advertisement
riicWARCS
A419-00-880 Issue K
3.
6
Nitrogen purge
(EPX
N series pumps)
WARNING
The EPX pump should not be used to pump pyrophoric gases or explosive mixtures.
WARNING
Dilute flammable gases to less than 25% of the
LEL
(Lower Explosive Limit) before the pump inlet.
The responsibility for ensuring the correct dilution of the pumped gas lies with the operator.
WARNING
The flow switch is set to 12 slm and therefore provides an indication that a flow in excess of 12 slm
is
present,
but gives no guarantee that there is sufficient flow to prevent condensation or to
provide sufficient dilution of the process gas to safe levels.
WARNING
The flow switch is not a guaranteed
interlock.
To ensure dilution of the process gas to safe
levels,
the system installer must fit appropriate interlocked hardware to ensure correct nitrogen purge
flow and
monitoring.
The following instructions apply to EPX N series pumps. They are not applicable to
EPX
L series pumps.
A 1
I
4 inch compression fitting is provided on the
pump,
marked 'N
2
Inlet'. Connect the nitrogen purge supply to the
nitrogen purge inlet connection using 1
I
4
inch
00
tube,
(refer to
Figure
6,
item
4).
Ensure that the nitrogen supply is stable to guarantee that the nitrogen purge
flow
is maintained. The nitrogen purge
gas should
comply
with the specifications detailed in
Table
10.
3.
7
Leak test the system
WARNING
Leak test the system and seal any leaks found to prevent the leakage of dangerous substances out
of the system and leakage of air into the
system.
Note:
If the exhaust
extraction
system
is
unrestricted,
and so cannot be sealed for leak test
purposes,
leak
test
the system before connecting to the pump
outlet.
Leak test the system, t hen
seal
any leaks found. Substances
which leak
from the system may be dangerous to people
,
and t here may be a danger of explosion if air leaks into the system.
As
supplied,
the
leak
rate of the EPX pump is tested to be less than 1
x
10·
5
mbar
l s·
1
(1
x
10·
3
Pal s·
1 ,
2.1 x
10·
8
atm
ft
3
min-
1 )
.
The required
leak
rate for the system will depend on t he safety and
process
requirements.
©
Edwards Limited
2017.
All rights
reserved.
Page 31
Edwards and the Edwards logo are trademarks of Edwards
Limited.
::J
V')
r-t'
QJ
-- --
QJ
r-t'
-·
0
::J
Advertisement
Table of Contents
