XA02751C
2-Pack/3-Pack TDLAS Gas Analyzer
18
Hauser
1.
Isolate the analyzer from the bypass following the procedure → 17.
2.
Close the sample supply shut-off valve to the SCS.
3.
Allow the sample bypass to flow until all residual gas has dissipated
from the lines as indicated by no flow on the sample bypass flow
meter.
4.
Close the low pressure flare or atmospheric vent header shut-off valve
for the effluent from the sample bypass.
5.
Turn off power to the analyzer.
Although the pressure reducing regulator at the process
sample tap is designed for “bubble-tight” shut off, this
condition may not occur after the system has been in
operation for an extended period. Isolation of the SCS from
the field pressure regulator will discontinue sample flow and
may cause the pressure at the outlet of the field pressure
regulator to slowly increase if “bubble-tight” shut off of the
pressure regulator does not occur. The slow pressure
increase will continue until the pressure setpoint of the relief
valve is reached and the excess pressure is vented by the
relief valve. Although this situation is not intended, it does
not cause a significant problem if the SCS is only isolated for
a short period. Only a small amount of process sample will be
vented when the relief valve opens because the pressure
regulator will continue to act as a flow restriction.
If the system will not be out of service for an extended period,
it is advised that power remain applied to the sample
transport line electric tracer, if applicable, and the sample
system enclosure heater.
Summary of Contents for 2-Pack TDLAS
Page 35: ......
