Man263.pub
Chapter: Troubleshooting
Topic: LeakChecking your GC
If the pressure does not dropat
all, or drops very slowly, then the
entire system is leak-tight. In
someways, this is thebest way to
check for leaks, because one test
verifies that every connection in
the system is holdingpressure.
Witha complex gas system, or
onewhere some of the fittings are
in-accessibleor hot itmay bediffi-
cult touse the leak check liquid or
meter. Also, the pressure drop
test can detect leaks that are too
small for theothermethods to see.
If the pressure does drop quickly,
there is a leak in the system. To
locate the sourceof the leak,
move the plug from theendof the
pneumatic system to the next fit-
tingupstreamand repeat the test.
If the systemnowholds pressure,
then the leakmust be somewhere
between the location of theprevi-
ous plugand the current plug.
Bymoving the plug location step
by step upstream, eventually it will
be obviouswhere the leakmust
be.
Plug thepneumatic system off at theendof the
gas flowpath. Youhave to knowwhere thegas
exits to theatmosphere
Injector
Detector
Column
PLUG
Directionof gas flow
Move theplug to the next fitting upstream in the
pneumatic system and repeat thepressure drop
test
Injector
Detector
Column
PLUG
Directionof gas flow
Againmove the plug to the next point upstream
and repeat the test. When the system does hold
pressure, youhavepassed the leak location
Injector
Detector
Column
PLUG
Directionof gas flow
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