CI Troubleshooting 3
69
Figure 4 Schematic of CI flow control module
Gas A
(methane)
supply
Gas B
(other gas)
supply
Gas A
select valve
Gas B
select valve
Mass
flow
controller
Calibration
valve
Restrictor
Calibration
vial
Shutoff valve
GC/MSD
interface
GC column
CI ion
source
Tab le 7 Flow module valve state diagram
Result
Gas A flow
Gas B flow
Purge
with Gas A
Purge
with Gas B
Pump out
flow module
Standby,
vented, or
EI mode
Gas A Open Closed Open Closed Closed Closed
Gas B Closed Open Closed Open Closed Closed
MFC On (at setpoint) On (at setpoint) On (at 100%) On (at 100%) On (at 100%) Off (at 0%)
Shutoff valve Open Open Open Open Open Closed